liu-wei (exact): 1000 papers, Hirsch index 16, Hirsch ratio 0.016.adsauthor "Liu, Wei; Liu, W." abstract

@--------------------------------------------------------------------Title: Investigation of the humping formation in the high power and high speed laser weldingAuthors: Ai, Yuewei; Jiang, Ping; Wang, Chunming; Mi, Gaoyang; Geng, Shaoning; Liu, Wei; Han, ChuBibliographic Code: 2018OptLE.107..102A

AbstractHigh power and high speed laser welding is as an attractive way to achieve the higher productivity in practical production. The weld periodical appearance defect, humping, is frequently generated in the high speed welding process. The weld quality is sequentially deteriorated severely due to the formed humping defect, which greatly limits the improvement of welding efficiency. In this paper, the keyhole and weld pool dynamic behaviors in the normal welding and high power high speed welding are investigated in the welding process of 304 stainless steel using 3-9 kW fiber laser at different welding speeds. The complex keyhole evolution, metal flow and metallic vapor are recorded by the high speed video camera and described in schematic illustration. The weld pool behaviors in normal welding and high power welding are compared and their effects on the humping formation are discussed in details. The results show that the tilted angle of keyhole, narrow and long molten pool, collision of fluid flow are the main factors for humping formation. Moreover, both of the microstructure characteristics of pre-humping and humping welds induced by molten pool behaviors are further analyzed and compared based on the SEM images, which is essential for reducing welding defects and achieving high quality welding with high efficiency.

@--------------------------------------------------------------------Title: Stochastic dynamics and stable equilibrium of evolutionary optional public goods game in finite populationsAuthors: Quan, Ji; Liu, Wei; Chu, Yuqing; Wang, XianjiaBibliographic Code: 2018PhyA..502..123Q

AbstractContinuous noise caused by mutation is widely present in evolutionary systems. Considering the noise effects and under the optional participation mechanism, a stochastic model for evolutionary public goods game in a finite size population is established. The evolutionary process of strategies in the population is described as a multidimensional ergodic and continuous time Markov process. The stochastic stable state of the system is analyzed by the limit distribution of the stochastic process. By numerical experiments, the influences of the fixed income coefficient for non-participants and the investment income coefficient of the public goods on the stochastic stable equilibrium of the system are analyzed. Through the numerical calculation results, we found that the optional participation mechanism can change the evolutionary dynamics and the equilibrium of the public goods game, and there is a range of parameters which can effectively promote the evolution of cooperation. Further, we obtain the accurate quantitative relationship between the parameters and the probabilities for the system to choose different stable equilibriums, which can be used to realize the control of cooperation.

@--------------------------------------------------------------------Title: The influence on the performance of CVD diamond coatings by the treatment of hydrogen peroxideAuthors: Liu, Wei; Man, Weidong; Cao, Yang; Lyu, Jilei; Sun, Jie; Yu, Jinghong; Dai, DanBibliographic Code: 2018Vacuu.152...91L

Abstract

@--------------------------------------------------------------------Title: Effect of nanohydroxyapatite on cadmium leaching and environmental risks under simulated acid rainAuthors: Zhao, Chenchen; Ren, Shuxia; Zuo, Qingqing; Wang, Shutao; Zhou, Yapeng; Liu, Wei; Liang, ShuxuanBibliographic Code: 2018ScTEn.627..553Z

Abstract

@--------------------------------------------------------------------Title: Investigating the efficiency of microscale zero valent iron-based in situ reactive zone (mZVI-IRZ) for TCE removal in fresh and saline groundwaterAuthors: Xin, Jia; Tang, Fenglin; Yan, Jing; La, Chenghong; Zheng, Xilai; Liu, WeiBibliographic Code: 2018ScTEn.626..638X

Abstract

@--------------------------------------------------------------------Title: A novel atmospheric tritium sampling systemAuthors: Qin, Lailai; Xia, Zhenghai; Gu, Shaozhong; Zhang, Dongxun; Bao, Guangliang; Han, Xingbo; Ma, Yuhua; Deng, Ke; Liu, Jiayu; Zhang, Qin; Ma, Zhaowei; Yang, Guo; Liu, Wei; Liu, GuiminBibliographic Code: 2018NIMPA.892..127Q

AbstractThe health hazard of tritium is related to its chemical form. Sampling different chemical forms of tritium simultaneously becomes significant. Here a novel atmospheric tritium sampling system (TS-212) was developed to collect the tritiated water (HTO), tritiated hydrogen (HT) and tritiated methane (CH3T) simultaneously. It consisted of an air inlet system, three parallel connected sampling channels, a hydrogen supply module, a methane supply module and a remote control system. It worked at air flow rate of 1 L/min to 5 L/min, with temperature of catalyst furnace at 200 C for HT sampling and 400 C for CH3T sampling. Conversion rates of both HT and CH3T to HTO were larger than 99%. The collecting efficiency of the two-stage trap sets for HTO was larger than 96% in 12 h working-time without being blocked. Therefore, the collected efficiencies of TS-212 are larger than 95% for tritium with different chemical forms in environment. Besides, the remote control system made sampling more intelligent, reducing the operator's work intensity. Based on the performance parameters described above, the TS-212 can be used to sample atmospheric tritium in different chemical forms.

@--------------------------------------------------------------------Title: Structure and thermoelectric property of Te doped paracostibite CoSb1-xTexS compoundsAuthors: You, Yonghui; Su, Xianli; Liu, Wei; Yan, Yonggao; Fu, Jiefei; Cheng, Xin; Zhang, Cheng; Tang, XinfengBibliographic Code: 2018JSSCh.262....1Y

AbstractParacostibite (CoSbS), a newly developed thermoelectric material, has aroused lots of interest due to its highly earth abundant and inexpensive constituent elements and potential application for thermoelectric power generation in the intermediate temperature range. Herein, a series of CoSb1-xTexS (x = 0-0.09) compounds were prepared by vacuum melting and annealing followed by SPS processing, and the effects of Te doping on the structure and thermoelectric properties were systematically investigated. Doping Te on the Sb site increases the carrier concentration up to 7.24 1020 cm-3 for CoSb0.93Te0.07S compound which is several orders of magnitude higher than that of un-doped CoSbS, and enhances the power factor. The maximum power factor of 14.07 muW cm-1 K-2 is attained at 900 K. Concomitantly, doping with Te on the Sb site leads to effective scattering of heat carrying phonon, accompanying with a strong suppression of the thermal conductivity with the increase of Te content, resulting in an increase of the ZT. A maximum ZT of 0.43 at 900 K is attained for CoSb0.93Te0.07S compound, which is 139% higher than that of un-doped CoSbS compound.

@--------------------------------------------------------------------Title: Solar photolysis of soluble microbial products as precursors of disinfection by-products in surface waterAuthors: Wu, Jie; Ye, Jian; Peng, Huanlong; Wu, Meirou; Shi, Weiwei; Liang, Yongmei; Liu, WeiBibliographic Code: 2018Chmsp.201...66W

Abstract

@--------------------------------------------------------------------Title: The role of temperature ramp-up time before barrier layer growth in optical and structural properties of InGaN/GaN multi-quantum wellsAuthors: Xing, Yao; Zhao, Degang; Jiang, Desheng; Liu, Zongshun; Zhu, Jianjun; Chen, Ping; Yang, Jing; Liu, Wei; Liang, Feng; Liu, Shuangtao; Zhang, Liqun; Wang, Wenjie; Li, Mo; Zhang, Yuantao; Du, GuotongBibliographic Code: 2018SuMi..117..228X

AbstractIn InGaN/GaN multi-quantum wells (MQWs), a low temperature cap (LT-cap) layer is grown between the InGaN well layer and low temperature GaN barrier layer. During the growth, a temperature ramp-up and ramp-down process is added between LT-cap and barrier layer growth. The effect of temperature ramp-up time duration on structural and optical properties of quantum wells is studied. It is found that as the ramp-up time increases, the Indium floating layer on the top of the well layer can be diminished effectively, leading to a better interface quality between well and barrier layers, and the carrier localization effect is enhanced, thereby the internal quantum efficiency (IQE) of QWs increases surprisingly. However, if the ramp-up time is too long, the carrier localization effect is weaker, which may increase the probabilities of carriers to meet with nonradiative recombination centers. Meanwhile, more nonradiative recombination centers will be introduced into well layers due to the indium evaporation. Both of them will lead to a reduction of internal quantum efficiency (IQE) of MQWs.

@--------------------------------------------------------------------Title: High-energy sodium-ion capacitor assembled by hierarchical porous carbon electrodes derived from EnteromorphaAuthors: Liu, Xiao; Wang, Huanlei; Cui, Yongpeng; Xu, Xiaonan; Zhang, Hao; Lu, Gaofei; Shi, Jing; Liu, Wei; Chen, Shougang; Wang, XinBibliographic Code: 2018JMatS..53.6763L

Abstract

@--------------------------------------------------------------------Title: Preparation and surface characteristics of Re3W matrix scandate cathode: An experimental and theoretical studyAuthors: Lai, Chen; Wang, Jinshu; Zhou, Fan; Liu, Wei; Hu, Peng; Wang, Changhao; Wang, Ruzhi; Miao, NaihuaBibliographic Code: 2018ApSS..440..763L

AbstractThe Scandia doped thermionic cathodes have received great attention owing to their high electron emission density in past two decades. Here, Scandia doped Re3W matrix scandate (RS) cathodes are fabricated by using Sc2O3 doped Re3W powders that prepared by spray drying method. The micromorphology, surface composition and chemical states of RS cathode are investigated with various modern technologies. It reveals that the reduction temperature of RS powders is dramatically increased by Sc2O3. On the surface of RS cathode, a certain amount of Sc2O3 nanoparticles and barium salt submicron particles are observed. According to the in situ Auger electron spectroscopy analysis, the concentration ratio of Ba:Sc:O is determined to be 2.9:1.1:2.7. The X-ray photoelectron spectroscopy data indicates that low oxidation state of Sc is clearly observed in scandate cathodes. The high atomic ratio of Ba on RS cathode surface is suggested due to the high adsorption of Re3W to Ba. Moreover, RS cathode shows better adsorption to Sc by comparison with conventional tungsten matrix scandate cathode. For RS cathode, the main depletion of Sc is suggested to -OSc desorbing from RS cathode surface. RS cathode is expected to be an impressive thermionic cathode with good emission properties and ion anti-bombarding insensitivity.

@--------------------------------------------------------------------Title: Simultaneous determination of Magnolol and Honokiol by amino acid ionic liquid synchronous fluorescence spectrometryAuthors: Liu, Wei; Zhu, XiashiBibliographic Code: 2018AcSpA.196..141L

AbstractA novel method based on amino acid ionic liquids (AAILs) as an additive synchronous fluorescence spectrometry is proposed for simultaneous determination of magnolol (MN) and honokiol (HN) in traditional Chinese medicine Houpu. The overlapping fluorescence spectrum of MN and HN could be completely separated in the AAILs medium. Experiment parameters (the type and concentration of AAILs, pH values and temperature) were discussed. The detection limits of MN and HN reached 1.46 ng/mL, 0.92 ng/mL and the recovery rates ranged from 98.6%-100.7%, 99.7%-100.6%, respectively. This methods was successfully employed for simultaneously determination of MN and HN in real samples. No significant differences could be found in the results of this method and the pharmacopoeia of People's Republic of China 2015 (Ch.P.2015). The experiment mechanisms were discussed by the Gaussian simulation and fluorescence quantum yield.

@--------------------------------------------------------------------Title: Effects of water and nitrogen addition on ecosystem respiration across three types of steppe: The role of plant and microbial biomassAuthors: Liu, Wei; L, Xiaotao; Xu, Wenfang; Shi, Huiqiu; Hou, Longyu; Li, Linghao; Yuan, WenpingBibliographic Code: 2018ScTEn.619..103L

Abstract

@--------------------------------------------------------------------Title: Performance analysis for minimally nonlinear irreversible refrigerators at finite cooling powerAuthors: Long, Rui; Liu, Zhichun; Liu, WeiBibliographic Code: 2018PhyA..496..137L

AbstractThe coefficient of performance (COP) for general refrigerators at finite cooling power have been systematically researched through the minimally nonlinear irreversible model, and its lower and upper bounds in different operating regions have been proposed. Under the tight coupling conditions, we have calculated the universal COP bounds under the chi figure of merit in different operating regions. When the refrigerator operates in the region with lower external flux, we obtained the general bounds (0 < epsilo 1.74 W m-1 K-1) are in general higher than those previously reported. Based on these findings, our study implies that the lattice thermal conductivity values of doped and pure single-crystalline SnSe were underestimated.

@--------------------------------------------------------------------Title: XOSS Transient Discovery Report for 2018-03-09Authors: Xu, J.; Zhang, M.; Zhang, X.; Zhao, J.; Liu, W.; Gao, J. R. A. X.Bibliographic Code: 2018TNSTR.326....1X

Abstract

@--------------------------------------------------------------------Title: A study for anticorrosion and tribological behaviors of thin/thick diamond-like carbon films in seawaterAuthors: Ye, Yewei; Jia, Shujuan; Zhang, Dawei; Liu, Wei; Zhao, HaichaoBibliographic Code: 2018SuTMP...6a4004Y

AbstractThe thin and thick diamond-like carbon (DLC) films were prepared by unbalanced magnetron sputtering technique on 304L stainless steels and (100) silicon wafers. Microstructure, mechanical, corrosion and tribological properties were systematically investigated by SEM, Raman, nanoindenter, scratch tester, modulab electrochemical workstation and R-tec multifunctional tribological tester. Results showed that the adhesion force presented a descending trend with the growth in soaking time. The adhesion force of the thin DLC film with high residual compressive stress (-3.72 GPa) was higher than that of the thick DLC film (-2.96 GPa). During the corrosion test, the thick DLC film showed a higher impendence and a lower corrosion current density than the thin DLC film, which is attributed to the barrier action of large thickness. Compared to bare 304L substrate, the friction coefficients and wear rates of DLC films in seawater were obviously decreased. Meanwhile, the thin DLC film with ideal residual compressive stress, super adhesion force and good plastic deformation resistance revealed an excellent anti-wear ability in seawater.

@--------------------------------------------------------------------Title: High-precision binocular measuring method considering three-dimensional distortionAuthors: Zhang, Yang; Zhao, Haiyang; Liu, Wei; Zhang, Zhiyuan; Di, Hongtu; Liang, Bing; Xing, Hongwen; Jia, ZhenyuanBibliographic Code: 2018SPIE10710E..1WZ

AbstractThe traditional vision measurement model has difficulty in guaranteeing the accuracy of measurement in the depth of field. And in this way, high-precision measurement of large components parts in three-dimensional large scale space can hardly be realized. To solve this problem, a binocular measuring method based on 3D image distortion compensation is proposed. Considering the rule of image distortion in the three-dimensional space, and combining with binocular vision measurement principle, a new binocular vision measurement model, based on 3D image distortion compensation, is established in the paper. And the model is based on the rule of image distortion in the three-dimensional space, and combined with binocular vision measurement principle. Besides, a new calibration method is proposed. This method is for the distortion parameters of the model and the intrinsic parameters of the cameras. Experimental results show that the proposed binocular vision measurement method in this paper is much more effectively than the traditional method. The results indicate that the proposed method largely improves the measurement accuracy under the condition of large depth of field. Meanwhile, this method also significantly improves the measurement accuracy in the three-dimensional space.

@--------------------------------------------------------------------Title: Local high precision 3D measurement based on line laser measuring instrumentAuthors: Zhang, Renwei; Liu, Wei; Lu, Yongkang; Zhang, Yang; Ma, Jianwei; Jia, ZhenyuanBibliographic Code: 2018SPIE10710E..1LZ

AbstractIn order to realize the precision machining and assembly of the parts, the geometrical dimensions of the surface of the local assembly surfaces need to be strictly guaranteed. In this paper, a local high-precision three-dimensional measurement method based on line laser measuring instrument is proposed to achieve a high degree of accuracy of the three-dimensional reconstruction of the surface. Aiming at the problem of two-dimensional line laser measuring instrument which lacks one-dimensional high-precision information, a local three-dimensional profile measuring system based on an accurate single-axis controller is proposed. First of all, a three-dimensional data compensation method based on spatial multi-angle line laser measuring instrument is proposed to achieve the high-precision measurement of the default axis. Through the pretreatment of the 3D point cloud information, the measurement points can be restored accurately. Finally, the target spherical surface is needed to make local three-dimensional scanning measurements for accuracy verification. The experimental results show that this scheme can get the local three-dimensional information of the target quickly and accurately, and achieves the purpose of gaining the information and compensating the error for laser scanner information, and improves the local measurement accuracy.

@--------------------------------------------------------------------Title: Associations of urinary phthalate metabolites with residential characteristics, lifestyles, and dietary habits among young children in Shanghai, ChinaAuthors: Liao, Chenxi; Liu, Wei; Zhang, Jialing; Shi, Wenming; Wang, Xueying; Cai, Jiao; Zou, Zhijun; Lu, Rongchun; Sun, Chanjuan; Wang, Heng; Huang, Chen; Zhao, ZhuohuiBibliographic Code: 2018ScTEn.616.1288L

Abstract

@--------------------------------------------------------------------Title: A self-powered nano-photodetector based on PFH/ZnO nanorods organic/inorganic heterojunctionAuthors: Li, Xiaoyun; Liu, Wei; Li, Peigang; Song, Jia; An, Yuehua; Shen, Jingqin; Wang, Shunli; Guo, DaoyouBibliographic Code: 2018ResPh...8..468L

AbstractPFH/ZnO nanorods heterojunctions were fabricated by spin-coating p-type Poly (9,9-dihexylfluorene) (PFH) on n-type vertically aligned ZnO nanorod arrays grown by a facile hydrothermal method on indium tin oxide (ITO) transparent conductive glass. A typical p-n junction behavior was observed in the fabricated heterojunction. The current of heterojunction increases and decreases dramatically by switching the illumination on and off at zero bias, showing potential self-powered photodetector applications. The heterojunction were capable of generating negative current when illuminated under an appropriate wavelength. The photoresponse properties of the heterojunction can be tuned by the applied bias. In vacuum, the rectifying behavior disappeared, and show only simple semiconductor behavior. Band structure of the heterojunction was schematic drawn and explain the mechanism of the properties of PFH/ZnO nanorods heterojunctions.

@--------------------------------------------------------------------Title: Observation of High Transformer Ratio of Shaped Bunch Generated by an Emittance-Exchange Beam LineAuthors: Gao, Q.; Ha, G.; Jing, C.; Antipov, S. P.; Power, J. G.; Conde, M.; Gai, W.; Chen, H.; Shi, J.; Wisniewski, E. E.; Doran, D. S.; Liu, W.; Whiteford, C. E.; Zholents, A.; Piot, P.; Baturin, S. S.Bibliographic Code: 2018PhRvL.120k4801G

AbstractCollinear wakefield acceleration has been long established as a method capable of generating ultrahigh acceleration gradients. Because of the success on this front, recently, more efforts have shifted towards developing methods to raise the transformer ratio (TR). This figure of merit is defined as the ratio of the peak acceleration field behind the drive bunch to the peak deceleration field inside the drive bunch. TR is always less than 2 for temporally symmetric drive bunch distributions and therefore recent efforts have focused on generating asymmetric distributions to overcome this limitation. In this Letter, we report on using the emittance-exchange method to generate a shaped drive bunch to experimentally demonstrate a TR &ap;5 in a dielectric wakefield accelerator.

@--------------------------------------------------------------------Title: Chromium-induced ferromagnetism with perpendicular anisotropy in topological crystalline insulator SnTe (111) thin filmsAuthors: Wang, Fei; Zhang, Hongrui; Jiang, Jue; Zhao, Yi-Fan; Yu, Jia; Liu, Wei; Li, Da; Chan, Moses H. W.; Sun, Jirong; Zhang, Zhidong; Chang, Cui-ZuBibliographic Code: 2018PhRvB..97k5414W, eprint = 1802.09715

AbstractTopological crystalline insulator is a recently discovered topological phase of matter. It possesses multiple Dirac surface states, which are protected by the crystal symmetry. This is in contrast to the time-reversal symmetry that is operative in the well-known topological insulators. In the presence of a Zeeman field and/or strain, the multiple Dirac surface states are gapped. The high-Chern-number quantum anomalous Hall (QAH) state is predicted to emerge if the chemical potential resides in all the Zeeman gaps. Here, we use molecular-beam epitaxy to grow 12 double-layer (DL) pure and Cr-doped SnTe (111) thin film on heat-treated SrTi O3 (111) substrate using a quintuple layer of insulating (Bi0.2Sb0.8 ) 2T e3 topological insulator as a buffer film. The Hall traces of Cr-doped SnTe film at low temperatures display square hysteresis loops indicating long-range ferromagnetic order with perpendicular anisotropy. The Curie temperature of the 12 DL S n0.9C r0.1Te film is 110 K. Due to the chemical potential crossing the bulk valence bands, the anomalous Hall resistance of 12 DL S n0.9C r0.1Te film is substantially lower than the predicted quantized value (1 /4 h /e2 ). It is possible that with systematic tuning the chemical potential via chemical doping and electrical gating, the high-Chern-number QAH state can be realized in the Cr-doped SnTe (111) thin film.

@--------------------------------------------------------------------Title: Performance analysis of coherent free space optical communications with sequential pyramid wavefront sensorAuthors: Liu, Wei; Yao, Kainan; Chen, Lu; Huang, Danian; Cao, Jingtai; Gu, HaijunBibliographic Code: 2018OptLT.100..332L

AbstractBased-on the previous study on the theory of the sequential pyramid wavefront sensor (SPWFS), in this paper, the SPWFS is first applied to the coherent free space optical communications (FSOC) with more flexible spatial resolution and higher sensitivity than the Shack-Hartmann wavefront sensor, and with higher uniformity of intensity distribution and much simpler than the pyramid wavefront sensor. Then, the mixing efficiency (ME) and the bit error rate (BER) of the coherent FSOC are analyzed during the aberrations correction through numerical simulation with binary phase shift keying (BPSK) modulation. Finally, an experimental AO system based-on SPWFS is setup, and the experimental data is used to analyze the ME and BER of homodyne detection with BPSK modulation. The results show that the AO system based-on SPWFS can increase ME and decrease BER effectively. The conclusions of this paper provide a new method of wavefront sensing for designing the AO system for a coherent FSOC system.

@--------------------------------------------------------------------Title: Compact sub-kilohertz low-frequency quantum light source based on four-wave mixing in cesium vaporAuthors: Ma, Rong; Liu, Wei; Qin, Zhongzhong; Su, Xiaolong; Jia, Xiaojun; Zhang, Junxiang; Gao, JiangruiBibliographic Code: 2018OptL...43.1243M, eprint = 1803.02882

AbstractUsing a nondegenerate four-wave mixing (FWM) process based on a double-{\Lambda} scheme in hot cesium vapor, we demonstrate a compact diode-laser-pumped quantum light source for the generation of quantum correlated twin beams with a maximum squeezing of 6.5 dB. The squeezing is observed at a Fourier frequency in the audio band down to 0.7 kHz which, to the best of our knowledge, is the first observation of sub-kilohertz intensity-difference squeezing in an atomic system so far. A phase-matching condition is also investigated in our system, which confirms the spatial-multi-mode characteristics of the FWM process. Our compact low-frequency squeezed light source may find applications in quantum imaging, quantum metrology, and the transfer of optical squeezing onto a matter wave.

@--------------------------------------------------------------------Title: Kinematics Control and Analysis of Industrial RobotAuthors: Zhu, Tongbo; Cai, Fan; Li, Yongmei; Liu, WeiBibliographic Code: 2018MS&E..320a2004Z

AbstractThe robot's development present situation, basic principle and control system are introduced briefly. Research is mainly focused on the study of the robot's kinematics and motion control. The structural analysis of a planar articulated robot (SCARA) robot is presented,the coordinate system is established to obtain the position and orientation matrix of the end effector,a method of robot kinematics analysis based on homogeneous transformation method is proposed, and the kinematics solution of the robot is obtained.Establishment of industrial robot's kinematics equation and formula for positive kinematics by example. Finally,the kinematic analysis of this robot was verified by examples.It provides a basis for structural design and motion control.It has active significance to promote the motion control of industrial robot.

@--------------------------------------------------------------------Title: Experiment Analysis and Modelling of Compaction Behaviour of Ag60Cu30Sn10 Mixed Metal PowdersAuthors: Zhou, Mengcheng; Huang, Shangyu; Liu, Wei; Lei, Yu; Yan, ShiweiBibliographic Code: 2018MS&E..317a2011Z

AbstractA novel process method combines powder compaction and sintering was employed to fabricate thin sheets of cadmium-free silver based filler metals, the compaction densification behaviour of Ag60Cu30Sn10 mixed metal powders was investigated experimentally. Based on the equivalent density method, the density-dependent Drucker-Prager Cap (DPC) model was introduced to model the powder compaction behaviour. Various experiment procedures were completed to determine the model parameters. The friction coefficients in lubricated and unlubricated die were experimentally determined. The determined material parameters were validated by experiments and numerical simulation of powder compaction process using a user subroutine (USDFLD) in ABAQUS/Standard. The good agreement between the simulated and experimental results indicates that the determined model parameters are able to describe the compaction behaviour of the multicomponent mixed metal powders, which can be further used for process optimization simulations.

@--------------------------------------------------------------------Title: Mg-MOF-74/MgF2 Composite Coating for Improving the Properties of Magnesium Alloy Implants: Hydrophilicity and Corrosion ResistanceAuthors: Liu, Wei; Yan, Zhijie; Ma, Xiaolu; Geng, Tie; Wu, Haihong; Li, ZhongyueBibliographic Code: 2018Mate...11..396L

Abstract

@--------------------------------------------------------------------Title: Oxidation Pathways for Ferrous Iron Smectites on Mars and the Redox Evolution of Gale CraterAuthors: Chemtob, S. M.; Rivera-Banuchi, V. B.; Catalano, J. G.; Nickerson, R. D.; Morris, R. V.; Agresti, D. G.; Liu, W.; Yee, N.Bibliographic Code: 2018LPI....49.2821C

AbstractOxidation of ferrous smectites produces nontronite and iron oxides. We discuss implications for the hematite-phyllosilicate facies of the Murray Formation.

@--------------------------------------------------------------------Title: Ultraviolet Photooxidation of Fe2+ --- Smectites and Implications for MarsAuthors: Rivera-Banuchi, V. B.; Liu, W.; Yee, N.; Glotch, T. D.; Legett, C.; Chemtob, S. M.Bibliographic Code: 2018LPI....49.2550R

AbstractPartial oxidation by UV radiation is shown for ferrous smectites, providing another alteration pathway for the production of ferric smectites on Mars.

@--------------------------------------------------------------------Title: Moderate Deviations for the Langevin Equation with Strong DampingAuthors: Cheng, Lingyan; Li, Ruinan; Liu, WeiBibliographic Code: 2018JSP...170..845C, eprint = 1703.03033

AbstractIn this paper, we establish a moderate deviation principle for the Langevin dynamics with strong damping. The weak convergence approach plays an important role in the proof.

@--------------------------------------------------------------------Title: Artificial twin-layer configurations of Zn(O,S) films by radio frequency sputtering in all dry processed eco-friendly Cu(In,Ga)Se2 solar cellsAuthors: Liu, Wei; Fan, Yu; Li, Xiaodong; Lin, Shuping; Liu, Yang; Shi, Sihan; Wang, He; Zhou, Zhiqiang; Zhang, Yi; Sun, YunBibliographic Code: 2018JPhD...51j5502L

AbstractCu(In,Ga)Se2 thin film solar cells are of great interest for research and industrial applications with their high conversion efficiencies, long-term stability and significant lifetimes. Such a solar cell of a p-n junction consists of p-type Cu(In,Ga)Se2 films as a light absorber and n-type CdS as a buffer layer, which often emerges with intrinsic ZnO. Aimed at eco-friendly fabrication protocols, a large number of strategies have been investigated to fabricate a Cd-free n-type buffer layer such as Zn(O,S) in Cu(In,Ga)Se2 solar cells. Also, if the Zn(O,S) films are prepared by coevaporation or sputtering, it will offer high compatibility with the preferred mass production. Here, we propose and optimize a dry method for Zn(O,S) deposition in a radio frequency sputtering. In particular, the strategy for the twin-layer configurations of Zn(O,S) films not only greatly improve their electrical conductance and suppress charge carrier recombination, but also avoid degradation of the Zn(O,S)/Cu(In,Ga)Se2 interfaces. Indeed, the high quality of such twin Zn(O,S) layers have been reflected in the similar conversion efficiencies of the complete solar cells as well as the large short-circuit current density, which exceeds the CdS reference device. In addition, Zn(O,S) twin layers have reduced the production time and materials by replacing the CdS/i-ZnO layers, which removes two fabrication steps in the multilayered thin film solar cells. Furthermore, the device physics for such improvements have been fully unveiled with both experimental current-voltage and capacitance-voltage spectroscopies and device simulations via wxAMPS program. Finally, the proposed twin-layer Zn(O,S)/Cu(In,Ga)Se2 interfaces account for the broadening of the depletion region of photogenerated charge carriers, which greatly suppress the carrier recombination at the space charge region, and eventually lead to the more efficient collection of charge carriers at both electrodes.

@--------------------------------------------------------------------Title: On the possibility of universal interstitial emission induced annihilation in metallic nanostructuresAuthors: Li, Xiangyan; Xu, Yichun; Duan, Guohua; Sun, Jingjing; Hao, Congyu; Zhang, Yange; Liu, Wei; Liu, C. S.; Fang, Q. F.Bibliographic Code: 2018JNuM..500..199L

AbstractNano-structured metals have been explored as self-healing materials for radiation damage due to vacancy-interstitial recombination at interfaces, such as grain boundaries (GBs) in nanocrystals (NCs) and free surfaces in nanoporous metals (NPs). The annihilation in copper was recently proposed to be via the interstitial-emission (IE) from the GB. However, whether the IE is applied as a possibly universal mechanism in other NPs and NCs deserves further investigation. The interstitial is often considered to overcome a large binding energy with the GB/surface to migrate out of the GB/surface and induce annihilation. In this work, with emphasis on the IE in tungsten where the interstitial is exceptionally tightly bound to the tungsten GB/surface, we found that the interstitial only needed to migrate over a small distance from the GB/surface to recombine with the vacancy nearby at a small energy barrier. During the process, the annihilation region around a static interstitial at the GB/surface propagated or extended greatly to the adjacent bulk area. The annihilation was found to be via the IE from the GB/surface or coupled vacancy hop with the IE. The ratio of the interstitial-GB/surface binding energy to the trapping-radius of the GB/surface for the interstitial was proposed to be a better qualitative indicator for the difficulty in the IE than the binding energy. Given that the IE works in the investigated NPs and NCs tungsten, iron and copper where the interstitials of distinct configurations bind with the GBs/surfaces at diverse levels, the IE mechanism may work universally in various nano-structured metals.

@--------------------------------------------------------------------Title: Processing and Characterization of Ag-Cu-Sn Brazing Alloy Prepared by a Mechanical Alloying MethodAuthors: Liu, Wei; Zheng, Miao; Wang, Xiaorong; Fan, Zhonghua; Yu, Dingkun; Chen, Rong; Shen, Hangyan; Guo, Jiayu; Guo, Bing; He, PengBibliographic Code: 2018JMEP...27.1148L

AbstractMechanical alloying was used to prepare an Ag-Cu-Sn brazing alloy with the low amounts of intermetallic compounds. X-ray diffraction and differential scanning calorimetry were carried out to investigate the phase transformation of the as-milled samples. It seemed that the intermetallic compounds experienced the stage of synthesis-decomposition-resynthesis in the ball milling process. By controlling the ball milling time and tin contents, the solid solution phases of Ag (Cu, Sn) and Ag (Cu) were achieved in the 60Ag30Cu10Sn sample after milling for 40 h. Although the intermetallic compound will be generated during the brazing process, the improvement of their distributed morphology is beneficial for the good bonding interface of the joint with stainless steel substrate.

@--------------------------------------------------------------------Title: BER Analysis of Coherent Free-Space Optical Communication Systems with a Focal-Plane-Based Wavefront SensorAuthors: Cao, Jingtai; Zhao, Xiaohui; Liu, Wei; Gu, HaijunBibliographic Code: 2018JKPS...72..555C

AbstractA wavefront sensor is one of most important units for an adaptive optics system. Based on our previous works, in this paper, we discuss the bit-error-rate (BER) performance of coherent free space optical communication systems with a focal-plane-based wavefront sensor. Firstly, the theory of a focal-plane-based wavefront sensor is given. Then the relationship between the BER and the mixing efficiency with a homodyne receiver is discussed on the basis of binary-phase-shift-keying (BPSK) modulation. Finally, the numerical simulation results are shown that the BER will be decreased obviously after aberrations correction with the focal-plane-based wavefront sensor. In addition, the BER will decrease along with increasing number of photons received within a single bit. These analysis results will provide a reference for the design of the coherent Free space optical communication (FSOC) system.

@--------------------------------------------------------------------Title: Discrimination and Measurements of Three Flavonols with Similar Structure Using Terahertz Spectroscopy and ChemometricsAuthors: Yan, Ling; Liu, Changhong; Qu, Hao; Liu, Wei; Zhang, Yan; Yang, Jianbo; Zheng, LeiBibliographic Code: 2018JIMTW.tmp..401Y

AbstractTerahertz (THz) technique, a recently developed spectral method, has been researched and used for the rapid discrimination and measurements of food compositions due to its low-energy and non-ionizing characteristics. In this study, THz spectroscopy combined with chemometrics has been utilized for qualitative and quantitative analysis of myricetin, quercetin, and kaempferol with concentrations of 0.025, 0.05, and 0.1 mg/mL. The qualitative discrimination was achieved by KNN, ELM, and RF models with the spectra pre-treatments. An excellent discrimination (100% CCR in the prediction set) could be achieved using the RF model. Furthermore, the quantitative analyses were performed by partial least square regression (PLSR) and least squares support vector machine (LS-SVM). Comparing to the PLSR models, the LS-SVM yielded better results with low RMSEP (0.0044, 0.0039, and 0.0048), higher Rp (0.9601, 0.9688, and 0.9359), and higher RPD (8.6272, 9.6333, and 7.9083) for myricetin, quercetin, and kaempferol, respectively. Our results demonstrate that THz spectroscopy technique is a powerful tool for identification of three flavonols with similar chemical structures and quantitative determination of their concentrations.

@--------------------------------------------------------------------Title: Wide Bandwidth and Enhanced Gain of a Low-Profile Dipole Antenna Achieved by Integrated Suspended MetasurfaceAuthors: Syed Nasser, Srien Sithara; Liu, Wei; Chen, Zhi NingBibliographic Code: 2018ITAP...66.1540S

Abstract

@--------------------------------------------------------------------Title: Repair of articular cartilage defects with acellular cartilage sheets in a swine modelAuthors: Xue, Jixin; He, Aijuan; Zhu, Yueqian; Liu, Yu; Li, Dan; Yin, Zongqi; Zhang, Wenjie; Liu, Wei; Cao, Yilin; Zhou, GuangdongBibliographic Code: 2018BioMa..13b5016X

AbstractAcellular cartilage sheets (ACSs) have been demonstrated as a good biomaterial for cartilage regeneration as a result of their natural cartilage matrix components, cartilage-specific structures, and good biocompatibility. However, it remains unknown whether allogeneic ACSs could promote cartilage regeneration and repair cartilage defects in a large animal model. The current study explored the feasibility of repairing articular cartilage defects using ACS scaffold with or without autologous bone marrow stromal cells (BMSCs) in a swine model. According to the current results, ACSs retained natural cartilage structure, primary cartilage matrices, and cartilage-specific growth factors. After cell seeding, ACSs presented good biocompatibility with BMSCs, which produced abundant extracellular matrix (ECM) proteins to cover the lacuna structures. In vivo results indicated that ACSs alone could induce endogenous host cells to regenerate cartilage and achieve generally satisfactory repair of cartilage defects at 6 months post-operation, including good interface integration and cartilage-specific ECM deposition. After combination with autologous BMSCs, BMSC-ACS constructs achieved more satisfactory repair of cartilage defects even without in vitro pre-induction of chondrogenesis. More importantly, all defects in both BMSC-ACS and ACS-only groups showed enhanced cartilage regeneration compared with BMSC--polyglycolic acid and blank groups, which mainly exhibited fibrogenesis in defect areas. Collectively, the current results indicate that ACSs can efficiently repair articular cartilage defects by promoting chondrogenic differentiation of BMSCs or inducing endogenous chondrogenesis in situ, thus serving as a good cartilage regeneration scaffold for recovery of articular function.

@--------------------------------------------------------------------Title: Adversarial Spatio-Temporal Learning for Video DeblurringAuthors: Zhang, Kaihao; Luo, Wenhan; Zhong, Yiran; Ma, Lin; Liu, Wei; Li, HongdongBibliographic Code: 2018arXiv180400533Z, eprint = 1804.00533

AbstractCamera shake or target movement often leads to undesired blur effects in videos captured by a hand-held camera. Despite significant efforts being devoted to video-deblur research, two major challenges remain: 1) how to model the spatio-temporal characteristics across both the spatial domain (i.e. image plane) and temporal domain (i.e. neighboring frames), and 2) how to restore sharp image details w.r.t. the conventionally adopted metric of pixel-wise error. In this paper, to address the first challenge, we propose a DeBLuRring Network (DBLRNet) for spatial-temporal learning by applying a modified 3D convolution to both spatial and temporal domains. Our DBLRNet is able to capture jointly spatial and temporal information encoded in neighboring frames, which directly contributes to improved video deblur performance. To tackle the second challenge, we use the developed DBLRNet as a generator in the GAN (generative adversarial network) architecture, and employ a content loss in addition to an adversarial loss for efficient adversarial training. The developed network, which we name as DeBLuRring Generative Adversarial Network (DBLRGAN), is tested on two standard benchmarks and achieves the state-of-the-art performance.

@--------------------------------------------------------------------Title: Gated Fusion Network for Single Image DehazingAuthors: Ren, Wenqi; Ma, Lin; Zhang, Jiawei; Pan, Jinshan; Cao, Xiaochun; Liu, Wei; Yang, Ming-HsuanBibliographic Code: 2018arXiv180400213R, eprint = 1804.00213

AbstractIn this paper, we propose an efficient algorithm to directly restore a clear image from a hazy input. The proposed algorithm hinges on an end-to-end trainable neural network that consists of an encoder and a decoder. The encoder is exploited to capture the context of the derived input images, while the decoder is employed to estimate the contribution of each input to the final dehazed result using the learned representations attributed to the encoder. The constructed network adopts a novel fusion-based strategy which derives three inputs from an original hazy image by applying White Balance (WB), Contrast Enhancing (CE), and Gamma Correction (GC). We compute pixel-wise confidence maps based on the appearance differences between these different inputs to blend the information of the derived inputs and preserve the regions with pleasant visibility. The final dehazed image is yielded by gating the important features of the derived inputs. To train the network, we introduce a multi-scale approach such that the halo artifacts can be avoided. Extensive experimental results on both synthetic and real-world images demonstrate that the proposed algorithm performs favorably against the state-of-the-art algorithms.

@--------------------------------------------------------------------Title: Multi-label Learning with Missing Labels using Mixed Dependency GraphsAuthors: Wu, Baoyuan; Jia, Fan; Liu, Wei; Ghanem, Bernard; Lyu, SiweiBibliographic Code: 2018arXiv180400117W, eprint = 1804.00117

AbstractThis work focuses on the problem of multi-label learning with missing labels (MLML), which aims to label each test instance with multiple class labels given training instances that have an incomplete/partial set of these labels. The key point to handle missing labels is propagating the label information from provided labels to missing labels, through a dependency graph that each label of each instance is treated as a node. We build this graph by utilizing different types of label dependencies. Specifically, the instance-level similarity is served as undirected edges to connect the label nodes across different instances and the semantic label hierarchy is used as directed edges to connect different classes. This base graph is referred to as the mixed dependency graph, as it includes both undirected and directed edges. Furthermore, we present another two types of label dependencies to connect the label nodes across different classes. One is the class co-occurrence, which is also encoded as undirected edges. Combining with the base graph, we obtain a new mixed graph, called MG-CO (mixed graph with co-occurrence). The other is the sparse and low rank decomposition of the whole label matrix, to embed high-order dependencies over all labels. Combining with the base graph, the new mixed graph is called as MG-SL (mixed graph with sparse and low rank decomposition). Based on MG-CO and MG-SL, we propose two convex transductive formulations of the MLML problem, denoted as MLMG-CO and MLMG-SL, respectively. Two important applications, including image annotation and tag based image retrieval, can be jointly handled using our proposed methods. Experiments on benchmark datasets show that our methods give significant improvements in performance and robustness to missing labels over the state-of-the-art methods.

@--------------------------------------------------------------------Title: Tagging like Humans: Diverse and Distinct Image AnnotationAuthors: Wu, Baoyuan; Chen, Weidong; Sun, Peng; Liu, Wei; Ghanem, Bernard; Lyu, SiweiBibliographic Code: 2018arXiv180400113W, eprint = 1804.00113

AbstractIn this work we propose a new automatic image annotation model, dubbed {\bf diverse and distinct image annotation} (D2IA). The generative model D2IA is inspired by the ensemble of human annotations, which create semantically relevant, yet distinct and diverse tags. In D2IA, we generate a relevant and distinct tag subset, in which the tags are relevant to the image contents and semantically distinct to each other, using sequential sampling from a determinantal point process (DPP) model. Multiple such tag subsets that cover diverse semantic aspects or diverse semantic levels of the image contents are generated by randomly perturbing the DPP sampling process. We leverage a generative adversarial network (GAN) model to train D2IA. Extensive experiments including quantitative and qualitative comparisons, as well as human subject studies, on two benchmark datasets demonstrate that the proposed model can produce more diverse and distinct tags than the state-of-the-arts.

@--------------------------------------------------------------------Title: Bidirectional Attentive Fusion with Context Gating for Dense Video CaptioningAuthors: Wang, Jingwen; Jiang, Wenhao; Ma, Lin; Liu, Wei; Xu, YongBibliographic Code: 2018arXiv180400100W, eprint = 1804.00100

AbstractDense video captioning is a newly emerging task that aims at both localizing and describing all events in a video. We identify and tackle two challenges on this task, namely, (1) how to utilize both past and future contexts for accurate event proposal predictions, and (2) how to construct informative input to the decoder for generating natural event descriptions. First, previous works predominantly generate temporal event proposals in the forward direction, which neglects future video context. We propose a bidirectional proposal method that effectively exploits both past and future contexts to make proposal predictions. Second, different events ending at (nearly) the same time are indistinguishable in the previous works, resulting in the same captions. We solve this problem by representing each event with an attentive fusion of hidden states from the proposal module and video contents (e.g., C3D features). We further propose a novel context gating mechanism to balance the contributions from the current event and its surrounding contexts dynamically. We empirically show that our attentively fused event representation is superior to the proposal hidden states or video contents alone. By coupling proposal and captioning modules into one unified framework, our model outperforms the state-of-the-arts on the ActivityNet Captions dataset with a relative gain of over 100% (Meteor score increases from 4.82 to 9.65).

@--------------------------------------------------------------------Title: Regularizing RNNs for Caption Generation by Reconstructing The Past with The PresentAuthors: Chen, Xinpeng; Ma, Lin; Jiang, Wenhao; Yao, Jian; Liu, WeiBibliographic Code: 2018arXiv180311439C, eprint = 1803.11439

AbstractRecently, caption generation with an encoder-decoder framework has been extensively studied and applied in different domains, such as image captioning, code captioning, and so on. In this paper, we propose a novel architecture, namely Auto-Reconstructor Network (ARNet), which, coupling with the conventional encoder-decoder framework, works in an end-to-end fashion to generate captions. ARNet aims at reconstructing the previous hidden state with the present one, besides behaving as the input-dependent transition operator. Therefore, ARNet encourages the current hidden state to embed more information from the previous one, which can help regularize the transition dynamics of recurrent neural networks (RNNs). Extensive experimental results show that our proposed ARNet boosts the performance over the existing encoder-decoder models on both image captioning and source code captioning tasks. Additionally, ARNet remarkably reduces the discrepancy between training and inference processes for caption generation. Furthermore, the performance on permuted sequential MNIST demonstrates that ARNet can effectively regularize RNN, especially on modeling long-term dependencies. Our code is available at: https://github.com/chenxinpeng/ARNet

@--------------------------------------------------------------------Title: Reconstruction Network for Video CaptioningAuthors: Wang, Bairui; Ma, Lin; Zhang, Wei; Liu, WeiBibliographic Code: 2018arXiv180311438W, eprint = 1803.11438

AbstractIn this paper, the problem of describing visual contents of a video sequence with natural language is addressed. Unlike previous video captioning work mainly exploiting the cues of video contents to make a language description, we propose a reconstruction network (RecNet) with a novel encoder-decoder-reconstructor architecture, which leverages both the forward (video to sentence) and backward (sentence to video) flows for video captioning. Specifically, the encoder-decoder makes use of the forward flow to produce the sentence description based on the encoded video semantic features. Two types of reconstructors are customized to employ the backward flow and reproduce the video features based on the hidden state sequence generated by the decoder. The generation loss yielded by the encoder-decoder and the reconstruction loss introduced by the reconstructor are jointly drawn into training the proposed RecNet in an end-to-end fashion. Experimental results on benchmark datasets demonstrate that the proposed reconstructor can boost the encoder-decoder models and leads to significant gains in video caption accuracy.

@--------------------------------------------------------------------Title: CNN in MRF: Video Object Segmentation via Inference in A CNN-Based Higher-Order Spatio-Temporal MRFAuthors: Bao, Linchao; Wu, Baoyuan; Liu, WeiBibliographic Code: 2018arXiv180309453B, eprint = 1803.09453

AbstractThis paper addresses the problem of video object segmentation, where the initial object mask is given in the first frame of an input video. We propose a novel spatio-temporal Markov Random Field (MRF) model defined over pixels to handle this problem. Unlike conventional MRF models, the spatial dependencies among pixels in our model are encoded by a Convolutional Neural Network (CNN). Specifically, for a given object, the probability of a labeling to a set of spatially neighboring pixels can be predicted by a CNN trained for this specific object. As a result, higher-order, richer dependencies among pixels in the set can be implicitly modeled by the CNN. With temporal dependencies established by optical flow, the resulting MRF model combines both spatial and temporal cues for tackling video object segmentation. However, performing inference in the MRF model is very difficult due to the very high-order dependencies. To this end, we propose a novel CNN-embedded algorithm to perform approximate inference in the MRF. This algorithm proceeds by alternating between a temporal fusion step and a feed-forward CNN step. When initialized with an appearance-based one-shot segmentation CNN, our model outperforms the winning entries of the DAVIS 2017 Challenge, without resorting to model ensembling or any dedicated detectors.

@--------------------------------------------------------------------Title: Life in the "Matrix": Human Mobility Patterns in the Cyber SpaceAuthors: Hu, Tianran; Luo, Jiebo; Liu, WeiBibliographic Code: 2018arXiv180308251H, eprint = 1803.08251

AbstractWith the wide adoption of the multi-community setting in many popular social media platforms, the increasing user engagements across multiple online communities warrant research attention. In this paper, we introduce a novel analogy between the movements in the cyber space and the physical space. This analogy implies a new way of studying human online activities by modelling the activities across online communities in a similar fashion as the movements among locations. First, we quantitatively validate the analogy by comparing several important properties of human online activities and physical movements. Our experiments reveal striking similarities between the cyber space and the physical space. Next, inspired by the established methodology on human mobility in the physical space, we propose a framework to study human "mobility" across online platforms. We discover three interesting patterns of user engagements in online communities. Furthermore, our experiments indicate that people with different mobility patterns also exhibit divergent preferences to online communities. This work not only attempts to achieve a better understanding of human online activities, but also intends to open a promising research direction with rich implications and applications.

@--------------------------------------------------------------------Title: Global Robust Practical Output Regulation for Nonlinear Systems in Output Feedback Form by Output-Based Event-Triggered ControlAuthors: Liu, Wei; Huang, JieBibliographic Code: 2018arXiv180301694L, eprint = 1803.01694

AbstractIn this paper, we study the event-triggered global robust practical output regulation problem for a class of nonlinear systems in output feedback form with any relative degree. Our approach consists of the following three steps. First, we design an internal model and an observer to form the so-called extended augmented system. Second, we convert the original problem into the event-triggered global robust practical stabilization problem of the extended augmented system. Third, we design an output-based event-triggered control law and a Zeno-free output-based event-triggered mechanism to solve the stabilization problem, which in turn leads to the solvability of the original problem. Finally, we apply our main result to the tracking problem of the controlled hyper-chaotic Lorenz systems.

@--------------------------------------------------------------------Title: Facile and green preparation of novel adsorption materials by combining sol-gel with ion imprinting technology for selective removal of Cu(II) ions from aqueous solutionAuthors: Ren, Zhongqi; Zhu, Xinyan; Du, Jian; Kong, Delong; Wang, Nian; Wang, Zhuo; Wang, Qi; Liu, Wei; Li, Qunsheng; Zhou, ZhiyongBibliographic Code: 2018ApSS..435..574R

AbstractA novel green adsorption polymer was prepared by ion imprinted technology in conjunction with sol-gel process under mild conditions for the selective removal of Cu(II) ions from aqueous solution. Effects of preparation conditions on adsorption performance of prepared polymers were studied. The ion-imprinted polymer was prepared using Cu(II) ion as template, N-[3-(2-aminoethylamino) propyl] trimethoxysilane (AAPTMS) as functional monomer and tetraethyl orthosilicate (TEOS) as cross-linker. Water was used as solvent in the whole preparation process. The imprinted and non-imprinted polymers were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), atomic force microscope (AFM), Brunauer, Emmett and Teller (BET) and zeta potential. Three-dimensional network structure was formed and functional monomer was successfully cross-linked into the network structure of polymers. Effects of adsorption conditions on adsorption performance of prepared polymers were studied too. The pH value is of great influence on adsorption behavior. Adsorption by ion-imprinted polymer was fast (adsorption equilibrium was reached within 60 min). The adsorption capacity of Cu(II) ion-imprinted polymer was always larger than that of non-imprinted polymer. Pseudo-second-order kinetics model and Freundlich isotherm model fitted well with adsorption data. The maximum adsorption capacity of Cu(II) ion-imprinted polymer was 39.82 mgg-1. However, the preparation conditions used in this work are much milder than those reported in literatures. The Cu(II) ion-imprinted polymer showed high selectivity and relative selectivity coefficients for Pb(II), Ni(II), Cd(II) and Co(II). In addition, the prepared ion-imprinted polymer could be reused several times without significant loss of adsorption capacity.

@--------------------------------------------------------------------Title: Synthesis and studies of axial chiral bisbenzocoumarins: Aggregation-induced emission enhancement properties and aggregation-annihilation circular dichroism effectsAuthors: Chen, Shaojin; Liu, Wei; Ge, Zhaohai; Zhang, Wenxuan; Wang, Kunpeng; Hu, ZhiqiangBibliographic Code: 2018AcSpA.193..141C

AbstractAxial chiral bisbenzocoumarins were synthesized for the first time by converting naphthanol units in 1,1'-binaphthol (BINOL) molecule to the benzocoumarin rings. The substitute groups on 3,3'-positions of bisbenzocoumarins showed significant influence on their aggregation-induced emission enhancement (AEE) properties. It was also found that BBzC1 with ester groups on 3,3'-positions exhibit an abnormal aggregation-annihilation circular dichroism (AACD) phenomenon, which could be caused by the decrease of the dihedral angle between adjacent benzocoumarin rings in the aggregation state. The single crystal structure of BBzC1 showed that the large dihedral angle in molecule prohibited the strong pi-pi stacking interactions, which could be main factors for its AEE properties.

@--------------------------------------------------------------------Title: Influence of in doping in GaN barriers on luminescence properties of InGaN/GaN multiple quantum well LEDsAuthors: Wang, Xiaowei; Yang, Jing; Zhao, Degang; Jiang, Desheng; Liu, Zongshun; Liu, Wei; Liang, Feng; Liu, Shuangtao; Xing, Yao; Wang, Wenjie; Li, MoBibliographic Code: 2018SuMi..114...32W

AbstractRoom-temperature photoluminescence (RT PL) spectra of InGaN/GaN multiple quantum well (MQW) structures grown by metalorganic chemical vapor deposition (MOCVD) was investigated. It is found that with increasing In content in GaN barriers, the FWHM and emission intensity decreases, and the emission wavelength is first red shift and then blue shift. The shrinkage of FWHM and emission wavelength blue shift can be attributed to the reduction of piezoelectric field, and the lower height of potential barrier will make carrier confinement weaker and ground state level lower, which resulting in emission intensity decreasing and wavelength red shift. In addition, doping the barrier with In will induce more inhomogeneous and deeper localized states in InGaN QWs, which also contribute to a red shift of PL emission wavelength.

@--------------------------------------------------------------------Title: Improved CORF model of simple cell combined with non-classical receptive field and its application on edge detectionAuthors: Sun, Xiao; Chai, Guobei; Liu, Wei; Bao, Wenzhuo; Zhao, Xiaoning; Ming, DelieBibliographic Code: 2018SPIE10608E..0RS

AbstractSimple cells in primary visual cortex are believed to extract local edge information from a visual scene. In this paper, inspired by different receptive field properties and visual information flow paths of neurons, an improved Combination of Receptive Fields (CORF) model combined with non-classical receptive fields was proposed to simulate the responses of simple cell's receptive fields. Compared to the classical model, the proposed model is able to better imitate simple cell's physiologic structure with consideration of facilitation and suppression of non-classical receptive fields. And on this base, an edge detection algorithm as an application of the improved CORF model was proposed. Experimental results validate the robustness of the proposed algorithm to noise and background interference.

@--------------------------------------------------------------------Title: Household environmental exposures during gestation and birth outcomes: A cross-sectional study in Shanghai, ChinaAuthors: Liu, Wei; Huang, Chen; Cai, Jiao; Wang, Xueying; Zou, Zhijun; Sun, ChanjuanBibliographic Code: 2018ScTEn.615.1110L

Abstract

@--------------------------------------------------------------------Title: A duodecennial national synthesis of antibiotics in China's major rivers and seas (2005-2016)Authors: Li, Si; Shi, Wanzi; Liu, Wei; Li, Huimin; Zhang, Wei; Hu, Jingrun; Ke, Yanchu; Sun, Weiling; Ni, JinrenBibliographic Code: 2018ScTEn.615..906L

Abstract

@--------------------------------------------------------------------Title: A sub-pixel method for estimating planting fraction of paddy rice in Northeast ChinaAuthors: Liu, Wei; Dong, Jie; Xiang, Kunlun; Wang, Sen; Han, Wei; Yuan, WenpingBibliographic Code: 2018RSEnv.205..305L

Abstract

@--------------------------------------------------------------------Title: Experimental Investigation of Spectra of Dynamical Maps and their Relation to non-MarkovianityAuthors: Yu, Shang; Wang, Yi-Tao; Ke, Zhi-Jin; Liu, Wei; Meng, Yu; Li, Zhi-Peng; Zhang, Wen-Hao; Chen, Geng; Tang, Jian-Shun; Li, Chuan-Feng; Guo, Guang-CanBibliographic Code: 2018PhRvL.120f0406Y

AbstractThe spectral theorem of von Neumann has been widely applied in various areas, such as the characteristic spectral lines of atoms. It has been recently proposed that dynamical evolution also possesses spectral lines. As the most intrinsic property of evolution, the behavior of these spectra can, in principle, exhibit almost every feature of this evolution, among which the most attractive topic is non-Markovianity, i.e., the memory effects during evolution. Here, we develop a method to detect these spectra, and moreover, we experimentally examine the relation between the spectral behavior and non-Markovianity by engineering the environment to prepare dynamical maps with different non-Markovian properties and then detecting the dynamical behavior of the spectral values. These spectra will lead to a witness for essential non-Markovianity. We also experimentally verify another simplified witness method for essential non-Markovianity. Interestingly, in both cases, we observe the sudden transition from essential non-Markovianity to something else. Our work shows the role of the spectra of evolution in the studies of non-Makovianity and provides the alternative methods to characterize non-Markovian behavior.

@--------------------------------------------------------------------Title: Megawatt peak power tunable femtosecond source based on self-phase modulation enabled spectral selectionAuthors: Chung, Hsiang-Yu; Liu, Wei; Cao, Qian; Song, Liwei; Krtner, Franz X.; Chang, GuoqingBibliographic Code: 2018OExpr..26.3684C

Abstract

@--------------------------------------------------------------------Title: Effect of carrier transfer process between two kinds of localized potential traps on the spectral properties of InGaN/GaN multiple quantum wellsAuthors: Liu, Wei; Zhao, Degang; Jiang, Desheng; Shi, Dongping; Zhu, Jianjun; Liu, Zongshun; Chen, Ping; Yang, Jing; Liang, Feng; Liu, Shuangtao; Xing, Yao; Zhang, Liqun; Wang, Wenjie; Li, Mo; Zhang, Yuantao; Du, GuotongBibliographic Code: 2018OExpr..26.3427L

Abstract

@--------------------------------------------------------------------Title: TEM and STEM Studies on the Cross-sectional Morphologies of Dual-/Tri-layer Broadband SiO2 Antireflective FilmsAuthors: Wang, Shuangyue; Yan, Hongwei; Li, Dengji; Qiao, Liang; Han, Shaobo; Yuan, Xiaodong; Liu, Wei; Xiang, Xia; Zu, XiaotaoBibliographic Code: 2018NRL....13...49W

AbstractDual-layer and tri-layer broadband antireflective (AR) films with excellent transmittance were successfully fabricated using base-/acid-catalyzed mixed sols and propylene oxide (PO) modified silica sols. The sols and films were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), transmission electron microscope (TEM), and scanning transmission electron microscope (STEM). FTIR and TEM results suggest that the PO molecules were covalently bonded to the silica particles and the bridge structure existing in PO modified silica sol is responsible for the low density of the top layer. The density ratio between different layers was measured by cross-sectional STEM, and the results are 1.69:1 and 2.1:1.7:1 from bottom-layer to top-layer for dual-layer and tri-layer films, respectively. The dual-layer film demonstrates good stability with 99.8% at the central wavelength of 351 nm and nearly 99.5% at the central wavelength of 1053 nm in laser system, and for the tri-layer AR film, the maximum transmittance reached nearly 100% at both the central wavelengths of 527 and 1053 nm.

@--------------------------------------------------------------------Title: Erythrocyte membrane-coated gold nanocages for targeted photothermal and chemical cancer therapyAuthors: Zhu, Dao-Ming; Xie, Wei; Xiao, Yu-Sha; Suo, Meng; Zan, Ming-Hui; Liao, Qing-Quan; Hu, Xue-Jia; Chen, Li-Ben; Chen, Bei; Wu, Wen-Tao; Ji, Li-Wei; Huang, Hui-Ming; Guo, Shi-Shang; Zhao, Xing-Zhong; Liu, Quan-Yan; Liu, WeiBibliographic Code: 2018Nanot..29h4002Z

AbstractRecently, red blood cell (RBC) membrane-coated nanoparticles have attracted much attention because of their excellent immune escapability; meanwhile, gold nanocages (AuNs) have been extensively used for cancer therapy due to their photothermal effect and drug delivery capability. The combination of the RBC membrane coating and AuNs may provide an effective approach for targeted cancer therapy. However, few reports have shown the utilization of combining these two technologies. Here, we design erythrocyte membrane-coated gold nanocages for targeted photothermal and chemical cancer therapy. First, anti-EpCam antibodies were used to modify the RBC membranes to target 4T1 cancer cells. Second, the antitumor drug paclitaxel (PTX) was encapsulated into AuNs. Then, the AuNs were coated with the modified RBC membranes. These new nanoparticles were termed EpCam-RPAuNs. We characterized the capability of the EpCam-RPAuNs for selective tumor targeting via exposure to near-infrared irradiation. The experimental results demonstrate that EpCam-RPAuNs can effectively generate hyperthermia and precisely deliver the antitumor drug PTX to targeted cells. We also validated the biocompatibility of the EpCam-RAuNs in vitro. By combining the molecularly modified targeting RBC membrane and AuNs, our approach provides a new way to design biomimetic nanoparticles to enhance the surface functionality of nanoparticles. We believe that EpCam-RPAuNs can be potentially applied for cancer diagnoses and therapies.

@--------------------------------------------------------------------Title: Electrochemical behavior and localized corrosion of X65 steel in high salt concentration brines with CO2 saturatedAuthors: Sun, Jianbo; Yang, Liying; Liu, Wei; Lu, MinxuBibliographic Code: 2018MRE.....5b6503S

AbstractThe electrochemical characteristics and localized corrosion of X65 steel were investigated in CO2-saturated brines as a function of salt concentration employing electrochemical techniques and immersion tests. The results show that, as salt concentration increases, the corrosion mechanism changes from electrochemical steps control to the mixed control of mass transfer and electrochemical steps. The higher the salt concentration is, the more obvious the mass transfer control will be. The corrosion rate firstly increases and then decreases with salt content. There is a maximum corrosion rate somewhere between 60 and 120 g l-1 salt content. The salting-out effect may play a crucial role in steel corrosion in CO2-bearing systems with higher salt concentrations. Chloride ions account for the decrease of the surface layer thickness and make them non-adherent, thereby promoting the initiation and development of localized corrosion at salt concentration above 120 g l-1.

@--------------------------------------------------------------------Title: Influence of InGaN layer growth temperature on luminescence properties of InGaN/GaN multiple quantum wellsAuthors: Wang, Xiaowei; Yang, Jing; Zhao, Degang; Jiang, Desheng; Liu, Zongshun; Liu, Wei; Liang, Feng; Liu, Shuangtao; Xing, Yao; Wang, Wenjie; Li, MoBibliographic Code: 2018MRE.....5b5906W

AbstractOptical investigation was performed on InGaN/GaN multiple quantum well (MQW) structures grown by metalorganic chemical vapor deposition (MOCVD) with different temperatures. It is found that the emission intensity decreases abruptly when the growth temperature of InGaN QW decreases from 710 to 670 C. The XRD measurements show that a poorer quality interface between the QW layers could decrease the emission quite a bit when the growth temperature is lower. In addition, due to the weakening surface mobility of adatoms, the localization states accompanied with defects are distributed more inhomogeneous at lower growth temperature, which is also responsible for the low emission intensity.

@--------------------------------------------------------------------Title: A source-depleted Early Jurassic granitic pluton from South China: Implication to the Mesozoic juvenile accretion of the South China crustAuthors: Zhou, Zuo-Min; Ma, Chang-Qian; Wang, Lian-Xun; Chen, Shu-Guang; Xie, Cai-Fu; Li, Yong; Liu, WeiBibliographic Code: 2018Litho.300..278Z

AbstractSource-depleted granites were rarely reported in South China. Hereby we identified such a granitic pluton, the Tiandong pluton, at Northeastern Guangdong province in Southeastern (SE) China. Whole-rock Sr-Nd and zircon Hf isotopes of the Tiandong granites both revealed obviously depleted source signatures, with initial isotopic values of initial 87Sr/86Sr = 0.7032-0.7040, epsiloNd(t) = 1.1-1.5, and epsiloHf(t) = 6-13, respectively. Zircon U-Pb dating implied the granite was intruded in Early Jurassic (188 Ma). The dominant minerals of the Tiandong granite consist of K-feldspar, plagioclase, quartz and biotite, with accessory mineral assemblage of apatite + zircon + magnetite. Based on the mineralogy and the depleted isotopic signature, the granites chemically show I-type affinity such as low Zr + Nb + Ce + Y (131.6 to 212.2), 104 Ga/Al (2.12-2.27), A/CNK values < 1.1 (0.97-1.03), corundum molecule < 1 (0-0.55) and extremely low P2O5 contents (0.05 wt%). The one-stage and two-stage depleted mantle Nd model ages (TDM = 0.89 to 0.84 Ga, T2DM = 0.88 to 0.85 Ga) are consistent. TDM(Hf) values of 0.31-0.63 Ga are also indistinguishable from T2DM(Hf) values of 0.35-0.75 Ga. The Nd and Hf isotopic compositions confirm that the Tiandong granites are juvenile crustal accretion but decoupled Nd-Hf isotopic systems. The juvenile crust is likely to originate from a mixed source of the primary asthenospheric mantle and the subordinate EMII. Combined with early studies of adjacent rocks, we propose that the early Jurassic ( 200-175 Ma) magmatism as evidenced by the Tiandong granites might be driven by upwelling of asthenosphere and subsequent underplating of mafic melts in an intra-plate extensional setting as a response to far-field stress during early stage subduction of the paleo-pacific plate.

@--------------------------------------------------------------------Title: Spectral property optimization for a narrow-band-filtered superfluorescent fiber sourceAuthors: Liu, Wei; Ma, Pengfei; Zhou, Pu; Jiang, ZongfuBibliographic Code: 2018LaPhL..15b5103L

AbstractThe spectral broadening properties of a narrow-band-filtered superfluorescent fiber source (SFS) with different spectral shapes and spectral widths are analyzed numerically for the first time. Similar to other types of incoherent light, it is revealed that there exists a spectral broadening saturation phenomenon for the narrow-band-filtered SFS, and the output spectral width plus the stimulated Raman scattering effect could be reduced through using an active fiber with a higher group-velocity dispersion coefficient. Besides, both the spectral shapes and spectral widths have a significant effect on the spectral broadening property and the stimulated Raman scattering threshold of the narrow-band-filtered stimulated Raman scattering, and the filtered SFS with narrower spectral width will broaden faster during amplification. The results help to optimize the spectral properties of the filtered SFS to obtain a narrower spectral width at a specified output power.

@--------------------------------------------------------------------Title: Leak-off mechanism and pressure prediction for shallow sediments in deepwater drillingAuthors: Tan, Qiang; Deng, Jingen; Sun, Jin; Liu, Wei; Yu, BaohuaBibliographic Code: 2018JOUC...17...65T

AbstractDeepwater sediments are prone to loss circulation in drilling due to a low overburden gradient. How to predict the magnitude of leak-off pressure more accurately is an important issue in the protection of drilling safety and the reduction of drilling cost in deep water. Starting from the mechanical properties of a shallow formation and based on the basic theory of rock-soil mechanics, the stress distribution around a borehole was analyzed. It was found that the rock or soil on a borehole is in the plastic yield state before the effective tensile stress is generated, and the effective tangential and vertical stresses increase as the drilling fluid density increases; thus, tensile failure will not occur on the borehole wall. Based on the results of stress calculation, two mechanisms and leak-off pressure prediction models for shallow sediments in deepwater drilling were put forward, and the calculated values of these models were compared with the measured value of shallow leak-off pressure in actual drilling. The results show that the MHPS (minimum horizontal principle stress) model and the FIF (fracturing in formation) model can predict the lower and upper limits of leak-off pressure. The PLC (permeable lost circulation) model can comprehensively analyze the factors influencing permeable leakage and provide a theoretical basis for leak-off prevention and plugging in deepwater drilling.

@--------------------------------------------------------------------Title: Effects of neutron irradiation on resistivity of reactor pressure vessel steelAuthors: Li, Chengliang; Shu, Guogang; Liu, Yi; Huang, Yili; Chen, Jun; Duan, Yuangang; Liu, WeiBibliographic Code: 2018JNuM..499..446L

AbstractThe embrittlement of reactor pressure vessel (RPV) steel owing to fast-neutron irradiation is one of its primary failure mechanisms. In this work, neutron irradiation tests were performed on an RPV steel at a high temperature (565 K) using a neutron irradiation test reactor. In addition, resistivity measurements were performed on the RPV steel both before and after irradiation in a hot laboratory using the four-probe method. The results showed that the resistivity of the RPV steel exhibits nonlinear behaviour with respect to the radiation fluence and that the nonlinearity becomes more pronounced with an increase in the radiation fluence. For instance, when the radiation fluence is 0.1540 dpa and the excitation current is increased from 0.2 mA to 200 mA, the resistivity of the RPV steel decreases by as much as 67.12%. During irradiation embrittlement, the resistivity increases with the fluence. When the radiation fluence is greater than 0.116 dpa, the increase in the resistivity accelerates. When the radiation fluence is less than 0.116 dpa and when an excitation current of 2 mA or 20 mA is used, the relationship between the resistivity and the radiation fluence for the RPV steel is a quadratic one, whereas that between the rate of change in the resistivity and the radiation fluence is a linear one. Thus, the resistivity of RPV steel can be used to characterise its degree of irradiation embrittlement, and resistivity measurements can be employed as a nondestructive evaluation technique for monitoring the degree of irradiation damage experienced by in-service RPV steel.

@--------------------------------------------------------------------Title: Mediating exchange bias by Verwey transition in CoO/Fe3O4 thin filmAuthors: Liu, X. H.; Liu, W.; Zhang, Z. D.; Chang, C. F.Bibliographic Code: 2018JAP...123h3903L

AbstractWe report the tunability of the exchange bias effect by the first-order metal-insulator transition (known as the Verwey transition) of Fe3O4 in CoO (5 nm)/Fe3O4 (40 nm)/MgO (001) thin film. In the vicinity of the Verwey transition, the exchange bias field is substantially enhanced because of a sharp increase in magnetocrystalline anisotropy constant from high-temperature cubic to low-temperature monoclinic structure. Moreover, with respect to the Fe3O4 (40 nm)/MgO (001) thin film, the coercivity field of the CoO (5 nm)/Fe3O4 (40 nm)/MgO (001) bilayer is greatly increased for all the temperature range, which would be due to the coupling between Co spins and Fe spins across the interface.

@--------------------------------------------------------------------Title: A new surface-potential-based compact model for the MoS2 field effect transistors in active matrix display applicationsAuthors: Cao, Jingchen; Peng, Songang; Liu, Wei; Wu, Quantan; Li, Ling; Geng, Di; Yang, Guanhua; Ji, Zhouyu; Lu, Nianduan; Liu, MingBibliographic Code: 2018JAP...123f4501C

AbstractWe present a continuous surface-potential-based compact model for molybdenum disulfide (MoS2) field effect transistors based on the multiple trapping release theory and the variable-range hopping theory. We also built contact resistance and velocity saturation models based on the analytical surface potential. This model is verified with experimental data and is able to accurately predict the temperature dependent behavior of the MoS2 field effect transistor. Our compact model is coded in Verilog-A, which can be implemented in a computer-aided design environment. Finally, we carried out an active matrix display simulation, which suggested that the proposed model can be successfully applied to circuit design.

@--------------------------------------------------------------------Title: Integrated Participatory and Collaborative Risk Mapping for Enhancing Disaster ResilienceAuthors: Liu, Wei; Dugar, Sumit; McCallum, Ian; Thapa, Gaurav; See, Linda; Khadka, Prakash; Budhathoki, Nama; Brown, Sarah; Mechler, Reinhard; Fritz, Steffen; Shakya, PujaBibliographic Code: 2018IJGI....7...68L

Abstract

@--------------------------------------------------------------------Title: A Fast V_{th} Measurement (FVM) Technique for NBTI Behavior CharacterizationAuthors: Yu, Xiao; Cheng, Ran; Liu, Wei; Qu, Yiming; Han, Jinghui; Chen, Bing; Lu, Jiwu; Zhao, YiBibliographic Code: 2018IEDL...39..172Y

Abstract

@--------------------------------------------------------------------Title: Carbon nanostructures/Mg hybrid materials for hydrogen storageAuthors: Liu, W.; Setijadi, E.; Crema, L.; Bartali, R.; Laidani, N.; Aguey-Zinsou, K. F.; Speranza, G.Bibliographic Code: 2018DRM....82...19L

Abstract

@--------------------------------------------------------------------Title: Suppression of electron and hole overflow in GaN-based near-ultraviolet laser diodesAuthors: Xing, Yao; Zhao, De-Gang; Jiang, De-Sheng; Li, Xiang; Liu, Zong-Shun; Zhu, Jian-Jun; Chen, Ping; Yang, Jing; Liu, Wei; Liang, Feng; Liu, Shuang-Tao; Zhang, Li-Qun; Wang, Wen-Jie; Li, Mo; Zhang, Yuan-Tao; Du, Guo-TongBibliographic Code: 2018ChPhB..27b8101X

Abstract

Project supported by the Science Challenge Project, China (Grant No. Z2016003), the National Key R & D Program of China (Grant Nos. 2016YFB0400803 and 2016YFB0401801), the National Natural Science Foundation of China (Grant Nos. 61674138, 61674139, 61604145, 61574135, 61574134, 61474142,