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Photoinduced self-stability mechanism of CdS photocatalyst:The dependence of photocorrosion and H_(2)-evolution performance 被引量:2
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作者 Yuxiao Chen Wei Zhong +3 位作者 Feng Chen Ping Wang Jiajie Fan Huogen Yu 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2022年第26期19-27,共9页
CdS photocorrosion is one of the most important factors that greatly affect the photocatalytic H_(2)-production rate and long-time stability.However,the reported works about CdS photocorrosion are mainly focused on th... CdS photocorrosion is one of the most important factors that greatly affect the photocatalytic H_(2)-production rate and long-time stability.However,the reported works about CdS photocorrosion are mainly focused on the surface oxidation by photogenerated holes,while the possible reduction of lattice Cd^(2+) by photogenerated electrons is usually ignored.In this work,the lattice Cd^(2+) reduction by photogenerated electrons during CdS photocorrosion were carefully investigated to reveal its potential effect on the microstructure change and photocatalytic H_(2)-production performance of CdS photocatalyst based on the two typical Na_(2)S-Na_(2)SO_(3) and lactic acid H_(2)-evolution systems.It was found that many isolated metallic Cd nanoparticles(5–50 nm)were produced on the CdS surface in the Na_(2)S-Na_(2)SO_(3) system,causing its serious destroy of CdS surface and a gradually decreased photocatalytic activity,while only a metallic Cd layer(2-3 nm)is homogeneously coated on the CdS surface in the lactic acid system,leading to an increased H-evolution rate.In fact,once a certain amount of metallic Cd was produced on the CdS surface,the resulting CdS-Cd composites can present a stable photocatalytic H_(2)-production activity and excellent stability for the final CdS-Cd photocatalysts.Hence,a photoinduced self-stability mechanism of CdS photocatalyst has been proposed,namely,the spontaneously produced metallic Cd contributes to the transformation of unstable CdS into stable CdS-Cd structure,with the simultaneous realization of final stable H_(2)-evolution performance. 展开更多
关键词 Photocatalysis H_(2)evolution CDS PHOTOCORROSION self-stability
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超空泡射弹的结构优化与稳定性分析
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作者 王康健 伍友利 +1 位作者 郝双鹏 荣光 《哈尔滨工程大学学报(英文版)》 CSCD 2023年第3期527-544,共18页
Stability is the key issue for kinetic-energy supercavitating projectiles.Our previous work established a six degrees of freedom(DOF)dynamic model for supercavitating projectiles.However,the projectile’s structure di... Stability is the key issue for kinetic-energy supercavitating projectiles.Our previous work established a six degrees of freedom(DOF)dynamic model for supercavitating projectiles.However,the projectile’s structure did not meet our current design specifications(its sailing distance could reach 100 m at an initial speed of 500 m/s).The emphasis of this study lies in optimizing the projectile’s configuration.Therefore,a program was developed to optimize the projectile’s structure to achieve an optimal design or the largest sailing distance.The program is a working optimal method based on the genetic algorithm(GA).Additionally,the convergence standard and population producing strategy were improved,which greatly elevated the calculation speed and precision.To meet design specifications,the improved GA was combined with the 6DOF model,which establishes a dynamic optimization problem.The new projectile’s structure was obtained by solving this problem.Then,the new structures’dynamic features were compared with the ideals proposed in this paper.The criterion of stability,which is called weakened self-stability,was redefined based on the results.The weakened self-stability is the optimal stability for an actual kinetic projectile motion,and it is instructive for the design of supercavitating projectiles in the future. 展开更多
关键词 Structural optimization self-stability tendency Supercavitating projectile Dynamic features Projectile stability
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Accuracy Analysis of Low Altitude Photogrammetry with Wide-angle Camera 被引量:5
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作者 Zongjian LIN Feifei XIE Guozhong SU 《Journal of Geodesy and Geoinformation Science》 2018年第1期30-38,共9页
Firstly,the relationship between the accuracy of low altitude aerial photogrammetry and the field angle of camera is made by a quantitative analysis from the theory.The conclusion that the low altitude photogrammetry ... Firstly,the relationship between the accuracy of low altitude aerial photogrammetry and the field angle of camera is made by a quantitative analysis from the theory.The conclusion that the low altitude photogrammetry should use wide-angle camera as much as possible is done.Then,the limitation of the single lens camera to expand field angle and the combined wide-angle camera existing on the market not suitable for light load of low altitude UAV(Unmanned Aerial Vehicle)due to excessive weight are pointed out.The characteristics of combined wide-angle low altitude light camera with self-calibration and self-stabilization developed by the author are described,especially the principle of self-calibration for the combination of static error and dynamic error.Based on the practice of large scale mapping,a technical procedure in aerial photography by taking with wide-angle camera and large overlap simultaneously for improving the accuracy of low altitude photogrammetry is proposed.The typical engineering produced data is used to verity the above theoretical analysis.A technical route for increasing accuracy of low altitude photogrammetry with combined wide-angle camera is expounded. 展开更多
关键词 low attitude PHOTOGRAMMETRY composed WIDE-ANGLE CAMERA computational reproduced IMAGERY SELF-CALIBRATION self-stability accuracy analysis
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THE SELF-STABLE REGION APPROACH FOR SECOND ORDER SYSTEMS 被引量:3
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作者 HUANG Yi HAN Jingqing(Institute of Systems Science, Academia Sinica, Beijing 100080, China) 《Systems Science and Mathematical Sciences》 SCIE EI CSCD 1999年第3期238-245,共8页
In this paper, an inherent property that second order systems, which can bestable, have the Self-Stable Regions (SSRs) is proposed. Based on this property, a newsynthesis method-the Self--Stable Region approach is sug... In this paper, an inherent property that second order systems, which can bestable, have the Self-Stable Regions (SSRs) is proposed. Based on this property, a newsynthesis method-the Self--Stable Region approach is suggested for a class of second-ordernonlinear uncertain systems. The global stability of the closed-loop systems is proved.Lastly, the advantages of the SSR approach are analyzed. 展开更多
关键词 NONLINEAR UNCERTAIN SYSTEMS synthesis method the Self-Stable Region(SSR)
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Orbital radius keeping of floating partial space elevator in cargo transposition
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作者 Gefei Shi Zheng H.Zhu 《Astrodynamics》 CSCD 2023年第3期259-269,共11页
A floating partial space elevator(PSE)is a PSE with a floating main satellite.This work aims to keep the orbital radius of the main satellite of a floating PSE in cargo transposition without the use of thrusts.A six-d... A floating partial space elevator(PSE)is a PSE with a floating main satellite.This work aims to keep the orbital radius of the main satellite of a floating PSE in cargo transposition without the use of thrusts.A six-degree-of-freedom two-piece dumbbell model was built to analyze the dynamics of a floating PSE.By adjusting the climber’s moving speed and rolling of the end body,the main satellite’s orbital radius can be kept.A novel control strategy using a proportional shrinking horizon model predictive control law containing a self-stability modified law is proposed to stabilize both the orbital and libration states to regulate the speed of only the climber.Simulation results validated the proposed control strategy.The system provides a successful approach to the desired equilibrium by the end of the transposition. 展开更多
关键词 floating partial space elevator(PSE) self-stability modified law shrinking horizon model predictive control
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Stability analysis of large-scale stope using stage subsequent fillingmining method in Sijiaying iron mine 被引量:15
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作者 Zhiqiang Yang Shuhua Zhai +1 位作者 Qian Gao Maohui Li 《岩石力学与工程学报》 EI CAS CSCD 北大核心 2015年第1期87-94,共8页
To improve mining production capacity, a stage subsequent filling mining(SSFM) method is employed for Sijiaying iron mine. The height of the stage stope is approximately 100 m. As there are farmlands and villages on t... To improve mining production capacity, a stage subsequent filling mining(SSFM) method is employed for Sijiaying iron mine. The height of the stage stope is approximately 100 m. As there are farmlands and villages on the surface of the mine, the surface deformation should be controlled when the ore is mined out for the purpose of stope stability and minimizing surface subsidence. In this paper, according to the site-specificgeological conditions, the self-stability of the stagefi lling body was analyzed, and the failure mechanism of back filling body was defined. Thus the relationship between the exposed height of filling body and the required strength was obtained. Next, the stability of back filling body and the characteristics of surface subsidence due to mining of 450 m level were analyzed using physical modeling.Finally, a three-dimensional numerical model was established using FLAC3 D, with which the surface subsidence and the stability of stope were achieved. The results show that the stope basically remains stable during the two-step recovery process. The maximum magnitude of the incline is 10.99 mm/m, a little larger than the permissible value of 10 mm/m, and the horizontal deformation is 5.9 mm/m,approaching the critical value of 6.0 mm/m, suggesting that the mine design is feasible for safety mining. 展开更多
关键词 STAGE subsequent FILLING mining (SSFM)method self-stability analysis of FILLING body Physical modeling Three-dimensional numerical mode
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Analysis and design for the second order nonlinear continuous extended states observer 被引量:66
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作者 Yi Huang Jingqing Han 《Chinese Science Bulletin》 SCIE EI CAS 2000年第21期1938-1944,共7页
The extended state observer (ESO) is a novel observer for a class of uncertain systems. Since ESO adopts the continuous non-smooth structure, the classical observer design theory is hard to use for ESO analysis. In th... The extended state observer (ESO) is a novel observer for a class of uncertain systems. Since ESO adopts the continuous non-smooth structure, the classical observer design theory is hard to use for ESO analysis. In this note, the self-stable region (SSR) approach, which is a nonlinear synthesis method for nonlinear uncertain systems, will be used for ESO design and its stability analysis. The advantages of the non-smooth structure in ESO for improving the convergence properties and the estimation precision will be shown. 展开更多
关键词 EXTENDED state observer (ESO) CONTINUOUS NON-SMOOTH structure self-stable region (SSR) method.
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Reactive poly(divinyl benzene-co-maleic anhydride) nanoparticles:Preparation and characterization 被引量:1
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作者 Jian He Dong Chen +3 位作者 Xu-Meng Fan Li-Wei Wang Jian-Yuan Deng Wan-Tai Yang 《Chinese Chemical Letters》 SCIE CAS CSCD 2013年第11期970-974,共5页
Polymeric nanoparticles(NPs)have drawn great interest in the past few years due to their potential applications in the felds of biomedical and optical technologies.However,it is still a challenge to prepare function... Polymeric nanoparticles(NPs)have drawn great interest in the past few years due to their potential applications in the felds of biomedical and optical technologies.However,it is still a challenge to prepare functional polymeric NPs,especially for particle diameters smaller than 50 nm.In this work,we demonstrate a one-pot method to fabricate reactive poly(divinyl benzene-co-maleic anhydride)NPs(PDVBMAH NPs)through a self-stable precipitation polymerization process.The size and morphology of these PDVBMAH NPs were characterized in detail by scanning electronic microscopy,and their chemical structure was determined by IR.The results showed that these NPs were highly cross-linked and their diameter was about 30 nm with narrow distribution.Additionally,the DVB and MAH endow the NPs with reactive surface anhydride and pendant vinyl groups,and these particles could be further functionalized through reaction of these groups.A plausible pathway was proposed for the formation of PDVBMAH NPs. 展开更多
关键词 Reactive polymeric nanoparticles Self-stable precipitation polymerizarion Anhydride groups Pendant carbon55carbon double bond Cross-linked
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