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31篇 您的检索式:作者名="WANG Zexin"
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1Effects of electric parameters on microstructure and properties of MAO coating fabricated on ZK60 Mg alloy in dual electrolyte显示文摘Micro-arc oxidation (MAO) process was carried out in a dual electrolyte system of NaAlO 2 and Na 3 PO 4 on ZK60 Mg alloys to explore the effect of electric parameters including current density, frequency, duty cycle and oxidation time on the evolution of coatings and other characteristics. The microstructural characteristics of coatings were observed by scanning electron microscopy (SEM) combined with the analysis of voltage-time responses during MAO process. Test of weight loss was conducted at a 3.5% NaCl solution to assess the resistance to corrosion. The results indicate that the current density and duty cycle play key roles on the coating quality. The peak voltage during MAO process increased with the increase in current density but the coating would be more easily detached when the current density was beyond a critical value. Voltage during MAO and microstructure of the coating were affected remarkably by duty cycle, and corrosion resistance was improved greatly when duty cycle was 40%. By means of single variable experiments, MAO process with optimized electric parameters was developed, which corresponds to the current density of 20 A dm 2 , frequency of 500 Hz, duty cycle of 40% and oxidation time of 15 min.Chen, Jing Wang, Zexin Lu, Sheng 2012Rare Metals2012,31,2:9
2Iterative freeform lens design for optical field control显示文摘It is still very challenging to determine a freeform lens for converting a given input beam into a prescribed output beam where not only the irradiance distribution but also the phase distribution hardly can be expressed analytically.Difficulties arise because the ray mapping from the input beam to the output beam is not only intertwined with the required double freeform surfaces but also intertwined with the output phase distribution,whose gradient represents the directions of the output rays.Direct determination of such a problem is very difficult.Here,we develop a special iterative wavefront tailoring(IWT)method to tackle this problem.In a certain iteration,the current calculation data of the double freeform surfaces and the output phase gradient are used to update the coefficients of a Monge–Ampère equation describing an intermediate wavefront next to the entrance freeform surface.The solution to the wavefront equation could lead to an improved ray mapping to be used to update the corresponding phase gradient data and reconstruct the double freeform surfaces.In a demonstrative example that deviates much from the paraxial or small-angle approximation,the new IWT method can generate a freeform lens that performs much better than that designed by a conventional ray mapping method for producing two irradiance distributions in the forms of numerals'1'and'2'on two successive targets,respectively.ZEXIN FENG DEWEN CHENG YONGTIAN WANG 2021Photonics Research2021,9,9:7
3In-situ surface decoration of RuO_(2) nanoparticles by laser ablation for improved oxygen evolution reaction activity in both acid and alkali solutions显示文摘Improving the OER activity of noble metal-based materials is of profound importance to minimize the usage of noble metals and lower the cost.Here,we report considerable improvement on the catalytic activity of RuO_(2) particles for OER in both alkali and acid environments.The RuO_(2) nanoparticles were treated with a method of pulse laser ablation.Numerous Ru and RuO_(2) clusters were generated at the surface of RuO_(2) nanoparticles after the laser ablation,forming a lychee-shaped morphology.The larger pulse energy RuO_(2) nanoparticles are treated with,the better the OER activity can be.DFT calculations shows that the surface tension induced by the lychee-shaped morphology benefits the OER performance.Our best sample gives an overpotential of 172 mV(at 10 mA cm^(-2))and a Tafel slope of 53.5 mV dec^(-1) in KOH,while an overpotential of 219 mV and a Tafel slope of 44.9 mV dec^(-1) in H_(2)SO_(4),which are of topclass results.This work may inspire a new way to develop high-performance electrocatalysts for OER.Zongpeng Wang Beibei Xiao Zhiping Lin Shijie Shen Aijiao Xu Zexin Du Yuchao Chen Wenwu Zhong 2021Journal of Energy Chemistry2021,30,3:4
4Hierarchical protection control system of smart substations显示文摘This paper analyzes the problems of the relay protections and secondary circuits of traditional substations,and introduces the hierarchical protection and control system of smart substations based on the technologies like IEC 61850 Standard,electronic instrument transformer,process level network,and wide area optical fiber communication network,etc.The hierarchical protection and control system includes three levels:local area protection,substation area protection and control,and wide area protection and control.These three levels are combined to solve the problems of the relay protections in traditional substations,thus improving protection performance and control capability of the system.Yuping ZHENG Delin WANG Zexin ZHOU Tuanjie CAO 2014Journal of Modern Power Systems and Clean Energy2014,2,3:3
5Intensification of the East Asian Monsoon in Southern China at about300-400 kaBP Inferred from Eolian Deposits in the Middle-lower Reaches of the Yangtze River显示文摘In the East Asian monsoon region,eolian deposits widely distributed in the middle-lower reaches of the Yantgze River are among the best materials available for studies on Quaternary climate change in the subtropical zone of Southern China.Typical eolian deposits in this region include upper Xiashu Loess(XL) and underlying Vermiculated Red Soil(VRS) layers.In this paper,chronological and paleoclimatic studies are conducted on an eolian deposit sequence near Jiujiang(JJ) city in northern Jiangxi province.A magnetostratigraphic study,combined with optically stimulated luminescence(OSL) dating,is conducted on the JJ section and provides further evidence that eolian deposits in the middle-lower reaches of the Yangtze River have been formed since the late Early Pleistocene,and that the boundary age between the XL and VRS layers is about 300-400 kaBP.In grain-size records of the JJ section,the median grain-size and content of the >30 μm size fraction increase sharply after 300-400 kaBP,representing an East Asian winter monsoon intensification event.Further pollen analysis reveals differing pollen assemblages before and after 300-400 kaBP:there is an evident increase in plants adapted to grow in a warm humid environment after 300-400 kaBP,implying an increase in precipitation caused by intensification of the East Asian summer monsoon.Global ice volume and uplift of the Tibet Plateau(TP) are regarded as crucial factors influencing variations of the East Asian monsoon on a long-term scale.The deep-sea δ^(18)O record,which reflects variations in global ice volume,shows no obvious change after 300-400 kaBP.Moreover,the influence of global ice volume changes on the East Asian summer and winter monsoons is inverse;the global ice volume increase(decrease) implies a strengthened(weakened) winter monsoon and weakened(strengthened) summer monsoon.We therefore interpret the coupled intensifications of the East Asian summer and winter monsoons at about 300-400 kaBP to the uplift of the TP in the Middle Pleistocene.This climate event is also documented in eolian deposits from the southern margin of the Chinese Loess Plateau(CLP) and from the desert-loess transitional belt.However,it is not recorded in the loess-paleosol sequences from the central part of the CLP,thereby indicating differing climate responses to TP uplift in different regions,which requires further study.QI Lin QIAO Yansong LI Yuehui WANG Yan PENG Shasha HE Zexin YANG Shuaibin HAN Chao ZHANG Xujiao 2017Acta Geologica Sinica(English Edition)2017,91,3:3
6Iterative freeform lens design for prescribed irradiance on curved target显示文摘Current freeform illumination optical designs are mostly focused on producing prescribed irradiance distributions on planar targets.Here,we aim to design freeform optics that could generate a desired illumination on a curved target from a point source,which is still a challenge.We reduce the difficulties that arise from the curved target by involving its varying z-coordinates in the iterative wavefront tailoring(IWT)procedure.The new IWT-based method is developed under the stereographic coordinate system with a special mesh transformation of the source domain,which is suitable for light sources with light emissions in semi space such as LED sources.The first example demonstrates that a rectangular flat-top illumination can be generated on an undulating surface by a spherical-freeform lens for a Lambertian source.The second example shows that our method is also applicable for producing a non-uniform irradiance distribution in a circular region of the undulating surface.Zexin Feng Dewen Cheng Yongtian Wang 2020Opto-Electronic Advances2020,3,7:2
7Research on the Impact of Distributed Generation on Relay Protection and Its Standards显示文摘Distributed generation(DG) will change characteristics of power flow and faults of traditional distribution network as well as the network operation mode, especially the operation of relay protection and automatic circuit breaker re-closing. In this paper, the characteristics and influences of several types of distributed generation and connection pattern, relay protection and automatic circuit breaker re-closing are analyzed. Standards of relay protection when distributed generation access to distribution network are discussed as well.Yang Guosheng Zhou Zexin Li Wei Liu Yu Liu Yadong Wang Xiaoyang Wang Wenhuan 2014Electricity2014,25,5:2
8Two vs three cycles of neoadjuvant sintilimab plus chemotherapy for resectable non-small-cell lung cancer:neoSCORE trial显示文摘Dear Editor,Lung cancer is the predominant cause of cancer-related deaths globally,with non-small cell lung cancer(NSCLC)accounting for 85%of all cases.1 The five-year overall survival(OS)after surgery remains poor because of the high rate of postoperative recurrence and metastasis.Recently,immune checkpoint inhibitors(ICIs)have shown promising efficacy in resectable NSCLC.Miner Shao Jie Yao Yunke Wang Lufeng Zhao Baizhou Li Lili Li Zuqun Wu Zexin Chen Junqiang Fan Fuming Qiu 2023Signal Transduction and Targeted Therapy2023,8,5:1
9Structural optimization of 2-D array probe for ACFM显示文摘CHEN Guoming LI Wei WANG Zexin 2007NDT&E International2007,40,6:1
10Structural optimazation of 2-D array probe for alternaing current field measurement显示文摘Chen Guoming Li Wei Wang Zexin 2007NDT&E International2007,40,6:1
11Structural optimization of 2-D array probe for alternating current field measurement显示文摘CHEN Guoming LI Wei WANG Zexin 2007NDT&E International2007,40,6:1
12Structural optimization of 2D array probe for alternating current field measurement显示文摘Chen Guoming Li Wei Wang Zexin 2007NDT&E International2007,40,:1
13Sturctural optimization of2-D array probe for ACFM显示文摘CHEN Guoming LI Wei WANG Zexin 2007NDT&EInternational2007,40,6:1
14Onboard actuator model-based Incremental Nonlinear Dynamic Inversion for quadrotor attitude control:Method and application显示文摘This paper addresses the robust attitude control problem for quadrotors subject to model mismatch and disturbances.A dynamic inversion based attitude control scheme is proposed,which consists of an outer loop attitude controller and an inner loop angular acceleration controller.The attitude controller is designed based on the Nonlinear Dynamic Inversion(NDI)to precisely linearize the nonlinear dynamics between the angular acceleration and the attitude.An onboard actuator model-based Incremental Nonlinear Dynamic Inversion(INDI)controller is designed in the angular acceleration control loop to improve the robustness against the model mismatch and disturbances.Meanwhile,the onboard actuator model with a modified structure eliminates the oscillation phenomenon when the sampling rate of the controller is higher than that of the actuator.Numerical simulations and flight tests demonstrate the effectiveness and robustness of the proposed controller in comparison with the PID controller.Zexin WANG Jiang ZHAO Zhihao CAI Yingxun WANG Ningjun LIU 2021Chinese Journal of Aeronautics2021,34,11:1
15Patterning thin polymer films by surface- directed dewetting and pattern transfer 显示文摘Zexin Zhang Zhe Wang 2003Plomyer2003,44,:1
16Calculations of lattice constants, energies of cohesion, and compressibilities of G@C_(60) (G= He, Ne, Ar ) molecular crystals显示文摘SINCE the discovery and subsequent macroscopic synthesis of fullerenes,due to their unusualstructure and widely potential applications,many theoretical and experimental scientists havedone a lot of work on fullerenes.Fullerenes are the hollow cage molecules,the large,closedspheroidal shapes suggest that they could hold a variety of small guest atoms and/orLIU Fengling, WANG Zexin and JIANG YunshengShandong Normal University, Jinan 250014, China 1997Chinese Science Bulletin1997,42,13:1
17Structural Optimization of 2-D Array Probe for ACFM 显示文摘CHEN Guoming LI Wei WANG Zexin 2007NDT&E International (S0963-8695)2007,40,6:1
18Kidney function change after transcatheter aortic valve replacement in patients with diabetes and/or hypertension显示文摘Aortic stenosis(AS)is a progressive heart valve disease occurring predominantly in older patients.According to a survey in a western country,the prevalence of AS is nearly 6.4%in patients over 75 years old(Carabello and Paulus,2009).Transcatheter aortic valve replacement(TAVR)is an alternative method for AS patients.Previous studies have described how up to 66%of TAVR patients have concomitant baseline kidney dysfunction(Ferro et al.,2015;Gargiulo et al.,2015).The majority of patients can benefit from the TAVR procedure with the recovery of kidney function.Jiaqi FAN Changjie YU Kaida REN Wanbing LIN Stella NG Zexin CHEN Xinping LIN Lihan WANG Qifeng ZHU Yuxin HE Jubo JIANG Xianbao LIU Jian'an WANG 2021Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)2021,22,3:1
19Simultaneous enhancement of strength and ductility in friction stir processed 2205 duplex stainless steel with a bimodal structure:experiments and crystal plasticity modeling显示文摘Achieving excellent strength-ductility synergy is a long-lasting research theme for structural materials.However,attempts to enhance strength usually induce a loss of ductility,i.e.,the strength-ductility trade-off.In the present study,the strength-ductility trade-off in duplex stainless steel(DSS)was overcome by developing a bimodal structure using friction stir processing(FSP).The ultimate tensile strength and elongation were improved by 140%and 109%,respectively,compared with those of the asreceived materials.Plastic deformation and concurrent dynamic recrystallization(DRX)during FSP were responsible for the formation of bimodal structure.Incompatible deformation resulted in the accumulation of dislocations at the phase boundaries,which triggered interpenetrating nucleation between the austenite and ferrite phases during DRX,leading to a bimodal structure.The in situ mechanical responses of the bimodal structure during tensile deformation were investigated by crystal plasticity finite element modeling(CPFEM).The stress field distribution obtained from CPFEM revealed that the simultaneous enhancement of strength and ductility in a bimodal structure could be attributed to the formation of a unique dispersion-strengthened system with the austenite and ferrite phases.It is indicated that the present design of alternating fine austenite and coarse ferrite layers is a promising strategy for optimizing the mechanical properties of DSSs.Yanying Hu Zexin Fang Yongbing Peng Weiqi Yang Xianfeng Ma Jinglong Li Yunqiang Zhao Biao Wang 2022Science China(Physics,Mechanics & Astronomy)2022,65,2:0
20Fully Decoupled Branch Energy Balancing Control Method for Modular Multilevel Matrix Converter Based on Sequence Circulating Components显示文摘The modular multilevel matrix converter(M3C)is a potential frequency converter for low-frequency AC transmission.However,capacitor voltage control of high-voltage and largecapacity M3C is more difficult,especially for voltage balancing between branches.To solve this problem,this paper defines sequence circulating components and theoretically analyzes the influence mechanism of different sequence circulating components on branch capacitor voltage.A fully decoupled branch energy balancing control method based on four groups of sequence circulating components is proposed.This method can control capacitor voltages of nine branches in horizontal,vertical and diagonal directions.Considering influences of both circulating current and voltage,a cross decoupled control is designed to improve control precision.Simulation results are taken from a low-frequency transmission system based on PSCAD/EMTDC,and effectiveness and precision of the proposed branch energy balancing control method are verified in the case of nonuniform parameters and an unbalanced power system.Zexin Zhao Weijiang Chen Zhichang Yang Guoliang Zhao Bin Han Yunfei Xu Nianwen Xiang Shulai Wang 2024CSEE Journal of Power and Energy Systems2024,10,1:0
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