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17篇 您的检索式:作者名="Zichen Wei"
    题名 作者 年代 出处 被引量
1Coupling effects of tungsten and molybdenum on microstructure and stress-rupture properties of a nickel-base cast superalloy显示文摘In order to comprehensively understand the forming mechanism of abnormal phases solidified in a nickel-base cast superalloy with additives of tungsten and molybdenum, the coupling effects of W and Mo on the microstructure and stress-rupture properties were investigated in this paper. The results indicated that the precipitation of primary α-(W, Mo) phase depended tremendously on the amount of W and Mo addition. When the total amount of W and Mo was greater than 5.79 at%, α-(W, Mo) phase became easily precipitated in the alloy.With increasing of Mo/W ratio, the dendrite-like α-(W, Mo) phases were apt to convert into small bars or blockylike phases at the vicinities of γ′/γ eutectic. The morphological changes of α-(W, Mo) phase can be interpreted as the non-equilibrium solidification of W and Mo in the alloy. Since the large sized α-(W, Mo) phase has detrimental effects on stress-rupture properties in as-cast conditions, secondary cracks may mainly initiate at and then propagate along the interfaces of brittle phases and soft matrix. During exposing at 1100 ℃ for 1000 h, the α-(W, Mo) phases transformed gradually into bigger and harder M_6C carbide, which results in decreasing of stress-rupture properties of the alloy. Finally, the alloy with an addition of 14W-1Mo(wt%) maintained the longest stress lives at high temperatures and therefore it revealed the best microstructure stability after 1100 ℃/1000 h thermal exposure.Tongjin Zhou Wei Feng Huibin Zhao Yu Meng Huaxia Zhang Hongsheng Ding Zichen Wang 2018Progress in Natural Science:Materials International2018,28,1:7
2Regulating Mechanical Properties of Polymer-Supramolecular Double-Network Hydrogel by Supramolecular Self-assembling Structures显示文摘Main observation and conclusion Polymer-supramolecular double-network hydrogels(PS-DN hydrogels)often show much improved recovery rates than conventional double-network hydrogels because of the fast self-assembling properties,making them attractive candidates for tissue engineering and flexible electronics.However,as the supramolecular network is dynamic and susceptible to break under low strains,the overall mechanical properties of PS-DN hydrogels are still limited.Here,we report the mechanical properties for PS-DN hydrogels can be significantly improved by tuning the supramolecular network structures.A single amino acid change of the self-assembling peptide can tune the assembled structures from nanofiber to nanoribbon.Such a microscopic structural change can greatly increase the Young's modulus(107.4 kPa),fracture stress(0.48 MPa),and toughness(0.38 MJ·m^(–3))of the PS-DN hydrogels.Moreover,the structural change also leads to slightly faster recovery rates(<1 s).We propose that such dramatically different mechanical properties can be understood by the impact of individual peptide rupture events on the overall network connectivity in the two scenarios.Our study may provide new inspirations for combining high mechanical strength and fast recovery in double network hydrogels by tuning the supramolecular network structures.Tiankuo Wang Yu Zhang Zichen Gu Wei Cheng Hai Lei Meng Qin Bin Xue Wei Wang Yi Cao 2021Chinese Journal of Chemistry2021,39,10:4
3High-Performance Photo-Modulated Thin-Film Transistor Based on Quantum dots/Reduced Graphene Oxide Fragment-Decorated ZnO Nanowires显示文摘In this paper, a photo-modulated transistor based on the thin-film transistor structure was fabricated on the flexible substrate by spin-coating and magnetron sputtering. A novel hybrid material that composed of Cd Se quantum dots and reduced graphene oxide(RGO) fragment-decorated ZnO nanowires was synthesized to overcome the narrow optical sensitive waveband and enhance the photo-responsivity. Due to the enrichment of the interface and heterostructure by RGO fragments being utilized, the photo-responsivity of the transistor was improved to 2000 AW^(-1) and the photo-sensitive wavelength was extended from ultraviolet to visible. In addition, a positive back-gate voltage was employed to reduce the Schottky barrier width of RGO fragments and ZnO nanowires. As a result, the amount of carriers was increased by 10 folds via the modulation of back-gate voltage. With these inherent properties, such as integrated circuit capability and wide optical sensitive waveband, the transistor will manifest great potential in the future applications in photodetectors.Zhi Tao Yi-an Huang Xiang Liu Jing Chen Wei Lei Xiaofeng Wang Lingfeng Pan Jiangyong Pan Qianqian Huang Zichen Zhang 2016Nano-Micro Letters2016,8,3:2
4The complex multi-symplectic scheme for the generalized sinh-Gordon equation显示文摘In this paper,the complex multi-symplectic method and the implementation of the generalized sinhGordon equation are investigated in detail.The multi-symplectic formulations of the generalized sinh-Gordon equation in Hamiltonian space are presented firstly.The complex method is introduced and a complex semi-implicit scheme with several discrete conservation laws(including a multi-symplectic conservation law(CLS),a local energy conservation law(ECL) as well as a local momentum conservation law(MCL)) is constructed to solve the partial differential equations(PDEs) that are derived from the generalized sinh-Gordon equation numerically.The results of the numerical experiments show that the multi-symplectic scheme has excellent long-time numerical behavior and high accuracy.HU WeiPeng DENG ZiChen HAN SongMei FAN Wei 2009Science China(Physics,Mechanics & Astronomy)2009,52,10:2
5(k, n) halftone visual cryptography based on Shamir' s secret sharing显示文摘(k,n) halftone visual cryptography( HVC) is proposed based on Shamir's secret sharing( HVCSSS),and through this method a binary secret image can be hided into n halftone images,and the secret image can be revealed from any k halftone images. Firstly,using Shamir's secret sharing,a binary secret image can be shared into n meaningless shares; secondly,hiding n shares into n halftone images through self-hiding method; and then n extracted shares can be obtained from n halftone images through self-decrypt method; finally,picking any k shares from n extracted shares,the secret image can be revealed by using Lagrange interpolation. The main contribution is that applying Shamir's secret sharing to realize a(k,n) HVC,and this method neither requires code book nor suffers from pixel expansion. Experimental results show HVCSSS can realize a(k,n) HVC in gray-scale and color halftone images,and correct decoding rate( CDR) of revealed secret image can be guaranteed.Ding Haiyang Li Zichen Bi Wei 2018The Journal of China Universities of Posts and Telecommunications2018,25,2:1
6Projected Runge-Kutta methods for constrained Hamiltonian systems显示文摘Projected Runge-Kutta(R-K) methods for constrained Hamiltonian systems are proposed.Dynamic equations of the systems,which are index-3 differential-algebraic equations(DAEs) in the Heisenberg form,are established under the framework of Lagrangian multipliers.R-K methods combined with the technique of projections are then used to solve the DAEs.The basic idea of projections is to eliminate the constraint violations at the position,velocity,and acceleration levels,and to preserve the total energy of constrained Hamiltonian systems by correcting variables of the position,velocity,acceleration,and energy.Numerical results confirm the validity and show the high precision of the proposed method in preserving three levels of constraints and total energy compared with results reported in the literature.Yi WEI Zichen DENG Qingjun LI Bo WANG 2016Applied Mathematics and Mechanics(English Edition)2016,37,8:1
7Targeted minicircle DNA delivery using folate–poly(ethylene glycol)–polyethylenimine as non-viral carrier显示文摘Chao Zhang Shijuan Gao Wei Jiang Song Lin Fusheng Du Zichen Li Wenlin Huang 2010Biomaterials2010,,23:1
8The influence of surfacemodification on the structure and properties of a calciumcarbonate filled poly(ethylene terephthalate)显示文摘Gao Wei Ma Xiaoyu Wang Zichen 2011Colloids andSurfaces A:Physicochemical and Engineering Aspects2011,389,23:1
9Pressureless two-step sintering of ultrafine-grained refractory metals:Tungsten-rhenium and molybdenum显示文摘The challenge of sintering ultrafine-grained refractory metals and alloys to full density is hereby addressed by pressureless two-step sintering in tungsten-rhenium alloy and pure molybdenum. Using properly processed nano powders(~50 nm average particle size), we are able to sinter W-10Re alloy to 98.4% density below 1200 ℃ while maintaining a fine grain size of 260 nm, and sinter molybdenum to 98.3% density below 1120 ℃ while maintaining a fine grain size of 290 nm. Compared to normal sintering,two-step sintering offers record-fine grain sizes and better microstructural uniformity, which translates to better mechanical properties with higher hardness(6.3 GPa for tungsten-rhenium and 4.0 GPa for molybdenum, both being the highest in all pressurelessly sintered samples of the respective material system)and larger Weibull modulus. Together with our previous demonstration in tungsten, we believe that twostep sintering is a general effective method to produce high-quality fine-grained refractory metals and alloys, and the lessons learned here are transferable to other materials for powder metallurgy.Zhongyou Que Zichen Wei Xingyu Li Lin Zhang Yanhao Dong Mingli Qin Junjun Yang Xuanhui Qu Ju Li 2022Journal of Materials Science & Technology2022,,31:1
10Development and validation of a predictive model for endocervical curettage in patients referred for colposcopy:A multicenter retrospective diagnostic study in China显示文摘Objective:This study aimed to develop a nomogram that can predict occult high-grade squamous intraepithelial lesions or worse(HSIL+)and determine the need for endocervical curettage(ECC)in patients referred for colposcopy.Methods:This retrospective multicenter study included 4,149 patients who were referred to any one of six tertiary hospitals in China for colposcopy between January 2020 and November 2021 because of abnormal screening results.ECC data were extracted from the medical records.Univariate and multivariate logistic regression analyses were performed to identify factors that could predict HSIL+on ECC.Patients were randomly assigned to a training set or to an internal validation set for performance and comparability testing.The model was externally validated and tested in patients from two additional hospitals.The nomogram was assessed in terms of discrimination and calibration and subjected to decision curve analysis.Results:HSIL+was found on ECC in 38.8%(n=388)of cases.Our predictive nomogram included age group,cytology,human papillomavirus(HPV)status,visibility of the cervix and colposcopic impression.The nomogram had good overall discrimination,which was internally validated[area under the receiver-operator characteristic(AUC),0.839;95%confidence interval(95%CI),0.773-0.904].In terms of external validation,the AUC was 0.843(95%CI,0.773-0.912)for the consecutive sample and 0.843(95%CI,0.783-0.902)for the comparative sample.Calibration analysis suggested good consistency between predicted and observed probabilities.Decision curve analysis suggested this nomogram would be clinically useful with almost the entire range of threshold probabilities.Conclusions:This internally and externally validated nomogram can be easily applied and incorporates multiple clinically relevant variables that can be used to identify patients with occult HSIL+who need ECC.Peng Xue Bingrui Wei Samuel Seery Qing Li Zichen Ye Yu Jiang Youlin Qiao 2022Chinese Journal of Cancer Research2022,34,4:1
11The influence of surface modification on the structure and properties of a calcium carbonate filled poly (ethylene terephthalate)显示文摘GAO Wei MA Xiaoyu WANG Zichen 0,,:1
12Superconductivity in ThMo_2Si_2C with Mo_2C square net显示文摘We report the superconductivity of a new quaternary compound ThMo_(2)Si_(2)C, synthesized with the arc-melting technique. The compound crystallizes in a tetragonal CeCr_(2)Si_(2)C-type structure with cell parameters of a = 4.2296A and c = 5.3571 A. An interlayer Si–Si covalent bonding is suggested by the atomic distance. The electrical resistivity and magnetic susceptibility measurements indicate a Pauli-paramagnetic metal with dominant electron-electron scattering in the normal-state. Bulk superconductivity at 2.2 K is demonstrated with a dimensionless specific-heat jump of △C/γnT = 0.98. The superconducting parameters of the critical magnetic fields, coherence length, penetration depth, and superconducting energy gap are given.ZiChen Liu BaiZhuo Li YuSen Xiao QingChen Duan YanWei Cui YuXue Mei Qian Tao ShuLi Wei ShuGang Tan Qiang Jing Qing Lu YuPing Sun YunYan Liu ShengGui Fu Hao Jiang Zhi Ren ZhuAn Xu Cao Wang GuangHan Cao 2021Science China(Physics,Mechanics & Astronomy)2021,64,7:1
13Laser tracking leader-follower automatic cooperative navigation system for UAVs显示文摘Currently,small payload and short endurance are the main problems of a single UAV in agricultural applications,especially in large-scale farmland.It is one of the important methods to solve the above problems of UAVs by improving operation efficiency through multi-UAV cooperative navigation.This study proposed a laser tracking leader-follower automatic cooperative navigation system for multi-UAVs.The leader in the cluster fires a laser beam to irradiate the follower,and the follower performs a visual tracking flight according to the light spot at the relative position of the laser tracking device.Based on the existing kernel correlation filter(KCF)tracking algorithm,an improved KCF real-time spot tracking method was proposed.Compared with the traditional KCF tracking algorithm,the recognition and tracking rate of the optimized algorithm was increased from 70%to 95%in indoor environment,and was increased from 20%to 90%in outdoor environment.The navigation control method was studied from two aspects:the distance coordinate transformation model based on micro-gyroscope and navigation control strategy.The error of spot position was reduced from the maximum(3.12,−3.66)cm to(0.14,0.12)cm by correcting the deviation distance of the spot at different angles through a coordinate correction algorithm.An image coordinate conversion model was established for a complementary metal-oxide-semiconductor(CMOS)camera and laser receiving device at different mounting distances.The laser receiving device was divided into four regions,S0-S3,and the speed of the four regions is calculated using an uncontrollable discrete Kalman filter.The outdoor flight experiments of two UAVs were carried out outdoors using this system.The experiment results show that the average flight error of the two UAVs on the X-axis is 5.2 cm,and the coefficient of variation is 0.0181.The average flight error on the Z-axis is 7.3 cm,and the coefficient of variation is 0.0414.This study demonstrated the possibility and adaptability of the developed system to achieve multi-UAVs cooperative navigation.Rui Ming Zhiyan Zhou Zichen Lyu Xiwen Luo Le Zi Cancan Song Yu Zang Wei Liu Rui Jiang 2022International Journal of Agricultural and Biological Engineering2022,15,2:0
14Investigation of the Focus Characteristics of a Triode Structure in FED显示文摘ZHANG Zichen LEI Wei ZHANG Xiaobing WANG Baoping YIN Hanchun TU Yan 2009Chinese Journal of Electronics2009,18,1:0
15Near-infrared fluorophores with absolute aggregation-caused quenching and negligible fluorescence re-illumination for in vivo bioimaging of nanocarriers显示文摘Environment-responsive fluorophores with aggregation-caused quenching(ACQ)properties have been applied to track nanocarriers with reduced artefacts caused by unbound or free fluorophores but suffer from incomplete fluorescence quenching and significant re-illumination,which undermine bioimaging accuracy.Herein,through structural modifications to reinforce the hydrophobicity,planarity and rigidity of fluorophores with an aza-BODIPY framework,probes featuring absolute ACQ(aACQ)and negligible re-illumination are developed and evaluated in various nanocarriers.aACQ probes,FD-B21 and FD-C7,exhibit near-infrared emission,high quantum yield,photostability,water sensitivity,and negligible re-illumination in blood,plasma and 1%Tween-80 in contrast to ACQ probe P2 and conventional probe DiR.All nanocarriers can be labeled efficiently by the tested fluorophores.Polymeric micelles(PMs)labeled by different aACQ probes manifest similar biodistribution patterns,which however differ from that of DiR-labeled PMs and could be ascribed to the appreciable re-illumination of DiR.Significantly lower re-illumination is also found in aACQ probes(2%-3%)than DiR(20%-40%)in Caco-2,Hela,and Raw264.7 cells.Molecular dynamics simulations unravel the molecular mechanisms behind aggregation and re-illumination,supporting the hypothesis of planarity dependency.It is concluded that aACQ fluorophores demonstrate excellent water sensitivity and negligible fluorescence re-illumination,making themselves useful tools for more accurate bioimaging of nanocarriers.Yifan Cai Xin Ji Yunsen Zhang Chang Liu Zichen Zhang Yongjiu Lv Xiaochun Dong Haisheng He Jianping Qi Yi Lu Defang Ouyang Weili Zhao Wei Wu 2023Aggregate2023,4,2:0
16Zeolite-based Fenton-like catalysis for pollutant removal and reclamation from wastewater显示文摘Wastewater treatment and reclamation from wastewater are essential for the sustainable use of water resource.Zeolite-based heterogeneous catalysis shows great potential in circumventing the current limitations on pollutant removal and transformation to useful chemicals,inspiring advancements towards practical water treatment.This paper summarizes the methods for synthesizing zeolite-based catalyst,and the corresponding advantages and disadvantages.In comparison with traditional Fenton-like reaction,the superiority of zeolite-based catalysis lies in less sludge,wide pH range and easy recyclability.Accordingly,applications of zeolite-based Fenton-like catalysis(ZFCs)in pollutant removal and reclamation of wastewater were reviewed.Emphasis was placed on the methodological strategies in improving ZFCs,including the combination of external driving force(e.g.,photocatalysis or electrochemistry),as well as the introduction of various transition metals into zeolite-based catalyst.Possible challenges and future perspectives for ZFCs were proposed.Zichen Shangguan Xingzhong Yuan Longbo Jiang Yanlan Zhao Lei Qin Xuerong Zhou Yan Wu Jia Wei Chew Hou Wang 2022Chinese Chemical Letters2022,33,11:0
17Development of UAV-based shot seeding device for rice planting显示文摘In order to realize the high-quality row seeding operation with unmanned aerial vehicle(UAV)in paddy field,a shot seeding device that can sow five rows of pelleted rice seeds at the same time was designed.The shot seeding device mainly consists of an external grooved wheel seed metering device and five shot seeding modules.The designed external grooved wheel seed metering device can take the seeds out of the seed box and divide the seeds into five parts.The shot seeding module can accelerate the pelleted rice seeds to reduce the impact of the UAV wind on the direction of seed movement.Furthermore,an angle adjustment mechanism for the shot seeding module was used to change the row spacing.The seed metering device test verified that when the speed of the seed metering wheel was 15 r/min,the coefficient of variation of the discharge rate of each row(C.V1)and total seed discharge rate stability(C.V2)were 1.70%and 1.04%,respectively.Image processing technique was used to test the UAV seeding performance.The distribution characteristics of seeds on the ground showed that the number of seeds in each row gradually increased from both sides to the middle in the width direction.According to the statistics,there were 60%-70%of the seeds in each row in the 100 mm width range.The field test showed that when the working height was 1.5 m and the seeding quantity was 38.56 kg/hm^(2),the performance of sowing in rows was obvious,the deviation rate of seeding quantity was 1.89%.After 16 d of sowing,the seeds’emergence rate was stable,and the average emergence rate was 82.63%and the yield was 6775.50 kg/hm^(2).Wei Liu Shuaishuai Zou Xuelang Xu Qingyu Gu Weizhuo He Jun Huang Junhao Huang Zichen Lyu Jianqin Lin Zhiyan Zhou Rui Jiang Xiwen Luo 2022International Journal of Agricultural and Biological Engineering2022,15,6:0
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