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Ratchet motion and current motors in pulsating reversal of coupled Brownian symmetric potentials

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Frontiers of physics 2017年第4期12卷 197-206页

作者： chen-pu li Hong-Bin chen Zhi-Gang Zheng Department of Physics Beijing Normal University Beijing 100875 China College of Science Hebei University of Architecture Zhangjiakou 075000 China Institute of Systems Science (ISS) Huaqiao University Xiamen 361021 China College of Information Science and Engineering Huaqiao University Xiamen 361021 China

In this study, we investigate the collective directed transport of coupled Brownian particles in spatially symmetric periodic potentials under time-periodic pulsating modulations. We find that the coupling between two particles can induce symmetry breaking and consequently collective directed motion. Moreover, the direction of motion can be reversed under certain conditions. The dependence of directed current on various parameters is systematically studied, reverse motion can be achieved by modulating the coupling free length and the phase shift of tile pulsating potential. The dynamical mechanism of these transport properties is understood in terms of the effective-potential theory and the space-time transformation invariance. The directed transport of coupled Brownian motors can be maniplflated and optimized by adjusting the coupling strength, pulsating frequency, or noise intensity.

关键词： coupled Brownian motors ratchet effective potential symmetric periodic potential noise

Rotation-translation coupling of a double-headed Brownian motor in a traveling-wave potential

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Frontiers of physics 2021年第3期16卷 165-175页

作者： Wei-Xia Wu chen-pu li Yan-li Song Ying-Rong Han Zhi-Gang Zheng Science Education Department Beijing Institute of Graphic CommunicationBeijing102600China College of Science Hebei University of ArchitectureZhangjiakou075000China School of Science Tianjin UniversityTianjin300072China School of Science Hebei University of TechnologyTianjin300401China Institute of Systems Science and College of Information Science and Engineering Huaqiao UniversityXiamen361021China

Considering a double-headed Brownian motor moving with both translational and rotational degrees of freedom,we investigate the directed transport properties of the system in a traveling-wave *** is found that the traveling wave provides the essential condition of the directed transport for the system,and at an appropriate angular frequency,the positive current can be optimized.A general current reversal appears by modulating the angular frequency of the traveling wave,noise intensity,external driving force and the rod *** transforming the dynamical equation in traveling-wave potential into that in a tilted potential,the mechanism of current reversal is *** both cases of Gaussian and Lévy noises,the currents show similar dependence on the ***,the current in the tilted potential shows a typical stochastic resonance *** external driving force has also a resonance-like effect on the current in the tilted *** the current in the traveling-wave potential exhibits the reverse behaviors of that in the tilted ***,the currents obviously depend on the stability index of the Lévy noise under certain conditions.

关键词： Brownian motor rotation-translation coupling traveling-wave potential current reversal

Depression of the Thoracolumbar Posterior Vertebral Body on the Estimation of Cement Leakage in Vertebroplasty and Kyphoplasty Operations

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Chinese Medical Journal 2015年第23期128卷 3158-3162页

作者： Hao chen pu Jia li Bao Fei Feng He Yang Jin-Jun li Hai Tang Department of Orthopaedics Beijing Friendship Hospital Capital Medical University Beijing 100050 China

Background： The cross-section ofthoracolumbar vertebral body is kidney-shaped with depressed posterior boundary. The anterior wall of the vertebral canal is separated from the posterior wall of the vertebral body on the lateral X-ray image. This study was designed to determine the sagittal distance between the anterior border of the vertebral canal and the posterior border of the vertebral body （DBCV） and to analyze the potential role of DBCV in the estimation of cement leakage during percutaneous vertebroplasty （PVP） or percutaneous kyphoplasty （PKP）. Methods： We retrospectively recruited 233 patients who had osteoporotic vertebral compression fractures and were treated with PVP or PKP. Computed tomography images of T11-L2 normal vertebrae were measured to obtain DBCV. The distance from cement to the posterior wall of the vertebral body （DCPW） of thoracolumbar vertebrae was measured from C-arm images. The selected vertebrae were divided into two groups according to DCPW, with the fracture levels, fracture grades and leakage rates of the two groups compared. A relative operating characteristic （ROC） curve was applied to determine whether the DCPW difference can be used to estimate the degree of cement leakage. The data were processed by statistical software SPSS version 21.0 using independent sample t-test and Chi-square tests. Results： The maximum DBCV was 6.40 mm and the average DBCV was 3.74 ± 0.95 mm. DBCV appeared to be longer in males than in females, but the difference was not statistically significant. The average DCPW of type-B leakage vertebrae （2.59 ±1.20 ram） was shorter than that of other vertebrae （7.83 ±2.38 mm, P 〈 0.001）. The leakage rate of group DCPW ≤6.40 mm was lower than that of group DCPW 〉6.40 mm for type-C and type-S, but much higher for type-B. ROC curve revealed that DCPW only has a predictive value for type-B leakage （area under the curve： 0.98, 95% confidence interval： 0.95-0.99, P 〈 0.001）, and when the cut-ott＇value was 4.05 mm, the di

关键词： C-arm Image Complications Kyphoplasty Vertebrae Vertebroplasty

Real-time Energy Management Method for Electric-hydrogen Hybrid Energy Storage Microgrids Based on DP-MPC

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 324-336页

作者： Qi li Xueli Zou Yuchen pu Weirong chen School of Electrical Engineering Southwest Jiaotong UniversityChengdu 611756China

With the increasing presence of intermittent energy resources in microgrids,it is difficult to precisely predict the output of renewable resources and their load *** order to realize the economical operations of the system,an energy management method based on a model predictive control(MPC)and dynamic programming(DP)algorithm is *** method can reasonably distribute the energy of the battery,fuel cell,electrolyzer and external grid,and maximize the output of the distributed power supply while ensuring the power balance and cost optimization of the *** on an ultra-shortterm forecast,the output power of the photovoltaic array and the demand power of the system load are *** offline global optimization of traditional dynamic programming is replaced by the repeated rolling optimization in a limited period of time to obtain power values of each unit in the energy storage *** with the traditional DP,MILP-MPC and the logic based real-time management method,the proposed energy management method is proved to be feasible and effective.

关键词： Electric-hydrogen hybrid energy economic energy management improved dynamic programming microgrid model predictive control

Two-stage Scheduling for Island CPHH IES Considering Plateau Climate

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CSEE Journal of Power and Energy Systems 2024年第4期10卷 1775-1786页

作者： Yuchen pu Qi li Yibin Qiu Xueli Zou Weirong chen School of Electrical Engineering Southwest Jiaotong UniversityChengdu 611756China

In this paper,an island integrated energy system(IES)combining power,heat and hydrogen(CPHH)is built,and optimal power-heat-hydrogen scheduling is studied under actual plateau meteorological *** the comprehensive demands of residents,an IES including renewable energy sources(RESs),fuel cell,electrolyzer,electric boiler,thermal energy storage device and new energy vehicles is established and *** the first stage of operation,according to the prediction of RESs and demands,day-ahead optimization is carried out which aims to minimize operation cost,while electric vehicles(EVs)are considered as special demand response(DR)*** the second stage of operation,ultra-short-term prediction is implemented to provide prediction data for model predictive control(MPC),realizing real-time *** as a CPHH system,the fuel cell and electrolyzer collaborate to meet various needs of the plateau residential area with high *** addition,the method and IES structure proposed in this paper is compared with other options.

关键词： CPHH feul cell hydrogen island IES scheduling

Engineering FeOOH/Ni(OH)_(2) heterostructures on Ni_(3)S_(2)surface to enhance seawater splitting

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Rare Metals 2024年第5期43卷 1989-1998页

作者： chen Yang Ya-Dong li li-Juan Cao Xi-Long Wang Han-pu liang Qingdao Institute of Bioenergy and Bioprocess Technology Chinese Academy of SciencesQingdao 266101China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Sino-Danish College University of Chinese Academy of SciencesBeijing 100049China

The construction of highly stable and efficient electrocatalysts is desirable for seawater splitting but remains challenging due to the high concentration of Cl-in ***,FeOOH/Ni(OH)_(2)heterostructure supported on Ni_(3)S_(2)-covered nickel foam(Fe–Ni/Ni_(3)S_(2)/NF)was fabricated by hydrothermal and etching methods,as well as anodic oxidation *** electronic structure of FeOOH and Ni(OH)_(2)could be modulated after depositing FeOOH nanoparticles on Ni(OH)_(2)nanosheet,which greatly boosted the catalytic *** the catalyst used as an electrode for oxygen evolution reaction(OER),it needed low overpotentials of 266 and 368 m V to achieve current densities of 100 and 800 m A·cm^(-2),respectively,in 1 mol·L^(-1)KOH+seawater *** can operate continuously at 100 m A·cm^(-2)for 400 h without obvious ***,in situ generated SO_(4)^(2-)from inner Ni_(3)S_(2)during electrolysis process would accumulate on the surface of active sites to form passivation layers to repel Cl^(-),which seemed to be responsible for superior *** study not only synthesizes an OER catalyst for highly selective and stable seawater splitting,but also gives a novel approach for industrial hydrogen production.

关键词： Anodic oxidation Heterostructure Oxygen evolution reaction Seawater splitting

Analysis of Pathological data of renal biopsy at one single center in China from 1987 to 2012

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Chinese Medical Journal 2014年第9期127卷 1715-1720页

作者： Zhang Xueguang liu Shuwen Tang li Wu Jie chen pu Yin Zhong li Minxia Xie Yuansheng Cai Guangyan Wei Ribao Qiu Qiang Wang Yuanda Shi Suozhu chen Xiangmei Department of Nephrology State Key Laboratory of Kidney Diseases (2011DAV00088) National Clinical Medical Research Center for Kidney Disease (2013BAI09B05) Chinese People's Liberation Army General Hospital Beijing 100853 China

Background In China,the prevalence of chronic kidney disease has increased *** studies shows that the spectrum of kidney disease had changed in recent *** retrospectively analyzed the pathological types of renal biopsy and its spectrum change at the General Hospital of the Chinese People＇s liberation Army from December 1987 to December 2012,in order to offer new supporting evidences for further specifying the distribution of renal pathological types in *** According to the ＂Revised Protocol for the Histological Typing of Glomerulopathy＂（WHO,1995）,pathological diagnosis of renal biopsy was classified,detection rate of each pathological type was summarized （i.e.,percentage of total renal biopsy cases）,study period was divided at an interval of 5 years,and age-stratified distribution change of main pathological types was *** The proportion of pathological types in 11 618 cases of renal biopsy was as follows：primary glomerulonephritis （PGN,70.7％）,secondary glomerulonephritis （SGN,20.7％）,tubular-interstitial nephropathy （4.0％）,hereditary/rare nephropathy （0.3％）,end-stage renal disease （0.9％）,and unclassified renal disease （3.3％）.Among PGN,there was IgA nephropathy （IgAN,37.0％）,membranous nephropathy （MN,11.8％）,mesangial proliferative glomerulonephritis （MsPGN,8.9％）,minimal change disease （MCD,6.6％）,and focal segmental glomerulosclerosis （3.9％）.Among SGN there was lupus nephritis （LN,5.5％）,Henoch-Sch（o）nlein purpura glomerulonephritis （5.3％）,hepatitis B virus-associated nephritis （HBVAN,3.03％）,diabetic nephropathy （2.2％）,and hypertension/malignant hypertension-associated renal damage （1.9％）.Pathological data were analyzed from 1987-1992 to 2008-2012 （after age adjustment）.Detection rate of IgAN tended to rise （P ＜0.001）.Detection rates of MN and MCD rose significantly （P ＜0.001）,but detection rate of MsPGN dropped significantly （P ＜0.001）.Among SGN,detection rate of HBVAN tended to drop （P ＜0.001）.Conclusion In China,PGN was the

关键词： renal biopsy kidney disease detection rate

Propagation form of internal cracks induced by continuous casting soft reduction and control strategy for internal quality

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Journal of Iron and Steel Research International 2024年第3期31卷 622-633页

作者： pu Wang liang chen Qun-wei Tang Wei-tao li Shao-xiang li Jia-quan Zhang School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China Weifang Special Steel Group Co..Ltd. Weifang 262400ShandongChina School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China

The propagation form of internal cracks induced by continuous casting soft reduction and the control strategy for enhancing the internal quality of 45 steel through industrial trials and a three-dimensional flow-heat transfer-solidification coupling model were *** results showed that the internal cracks induced by soft reduction exhibited a characteristic of being"coarse in the middle and fine at both ends",and displayed an elliptical arc distribution on the loose side of the strand cross *** cracks originated within the brittle temperature range and propagated inward to the liquid impenetrable temperature and outward to the zero ductility temperature or *** control strategy for enhancing the internal quality of the 45 steel strand through soft reduction is to adjust the casting speed or the reduction zone appropriately,ensuring that the central solid fraction of the reduction zone falls within the range of *** this point,a reasonable reduction amount is allocated to eliminate the center shrinkage cavities and center segregation,even if it results in minor reduction-induced cracks.

关键词： Continuous casting Soft reduction Crack propagation Internal quality Control strategy

Research on aiming methods for small sample size shooting tests of two-dimensional trajectory correction fuse

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Defence Technology（防务技术） 2024年第3期33卷 506-517页

作者： chen liang Qiang Shen Zilong Deng Hongyun li Wenyang pu lingyun Tian Ziyang lin School of Mechatronical Engineering Beijing Institute of TechnologyBeijing 100081China

The longitudinal dispersion of the projectile in shooting tests of two-dimensional trajectory corrections fused with fixed canards is extremely large that it sometimes exceeds the correction ability of the correction fuse *** impact point easily deviates from the target,and thus the correction result cannot be readily ***,the cost of shooting tests is considerably high to conduct many tests for data *** address this issue,this study proposes an aiming method for shooting tests based on small sample *** proposed method uses the Bootstrap method to expand the test data;repeatedly iterates and corrects the position of the simulated theoretical impact points through an improved compatibility test method;and dynamically adjusts the weight of the prior distribution of simulation results based on Kullback-Leibler divergence,which to some extent avoids the real data being"submerged"by the simulation data and achieves the fusion Bayesian estimation of the dispersion *** experimental results show that when the simulation accuracy is sufficiently high,the proposed method yields a smaller mean-square deviation in estimating the dispersion center and higher shooting accuracy than those of the three comparison methods,which is more conducive to reflecting the effect of the control algorithm and facilitating test personnel to iterate their proposed structures and algorithms.;in addition,this study provides a knowledge base for further comprehensive studies in the future.

关键词： Two-dimensional trajectory correction fuse Small sample size test Compatibility test KL divergence Fusion bayesian estimation