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Numerical analysis of magnetization AC losses in high-temperature superconducting slabs subjected to uniform strains

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Science China(Technological Sciences) 2014年第4期57卷 765-772页

作者： xia Jing zhou Youhe Key Laboratory of Mechanics on Disaster and Environment in Western China attached to the Ministry of Education of China and Department of Mechanics and Engineering Sciences College of Civil Engineering and Mechanics Lanzhou University

high-temperature superconductors in superconductor apparatuses are subjected to mechanical strains under operating *** strains cause the degradation of the critical current densities and influence AC losses in the *** on the dynamic process of thermomagnetic interaction,we report the results of numerical analysis of AC losses in an infinite high-temperature superconducting slab subjected to a uniform in-plane strain in an alternating external magnetic field parallel to the sample *** numerical analysis shows the details of electromagnetic phenomena in the slab and the dependences of AC loss on various external parameters including the uniform strain in the slab and the amplitude and frequency of the external magnetic *** this paper,we find that whether the magnetic field fully penetrates the superconductor is the key factor that influences the features of AC *** the magnetic field cannot fully penetrate the superconductor,the loss rises with.increasing strain or decreasing *** the magnetic field can fully penetrate the superconductor,the feature is just *** also analyze the effects of periodic strain on AC *** is interesting to find that when the periodic strain frequency equals the external magnetic field frequency,the AC loss reaches the maximum,regardless if the magnetic field fully penetrates the superconductor or not.

关键词： high-temperature superconducting slab AC loss strain

Estimated conditional score function for missing mechanism model with nonignorable nonresponse

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Science China Mathematics 2017年第7期60卷 1197-1218页

作者： CUi xia zhou Yong School of Economics and Statistics Guangzhou University Academy of Mathematics and Systems Science Chinese Academy of Sciences School of Statistics and Management Shanghai University of Finance and Economics

Missing data mechanism often depends on the values of the responses,which leads to nonignorable *** such a situation,inference based on approaches that ignore the missing data mechanism could not be valid.A crucial step is to model the nature of *** specify a parametric model for missingness mechanism,and then propose a conditional score function approach for *** approach.imputes the score function by taking the conditional expectation of the score function for the missing data given the available *** procedure is then followed by replacing unknown terms with the related nonparametric estimators based on the observed *** proposed score function does not suffer from the non-identifiability problem,and the proposed estimator is shown to be consistent and asymptotically *** also construct a confidence region for the parameter of interest using empirical likelihood *** studies demonstrate that the proposed inference procedure performs well in many *** apply the proposed method to a data set from research.in a growth hormone and exercise intervention study.

关键词： conditional score function empirical likelihood missing data nonignorabe nonresponse

PhASE TRANSiTiON iN SEQUENCE UNiQUE RECONSTRUCTiON

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Journal of Systems Science & Complexity 2007年第1期20卷 18-29页

作者： Li xia Chan zhou Theoretical Life Science Research Center Fudan University Shanghai 200433 China James D. Waston institute of Genome Sciences Zhejiang University Hangzhou 310008 China.

in this paper, sequence unique reconstruction refers to the property that a sequence is uniquely reconstructable from all its K-tuples. We propose and study the phase transition behavior of the probability P（K） of unique reconstruction with regard to tuple size K in random sequences （iid model）. Based on Monte Carlo experiments, artificial proteins generated from lid model exhibit a phase transition when P（K） abruptly jumps from a low value phase （e.g. 〈 0.1） to a high value phase （e.g. 〉 0.9）. With a generalization to any alphabet, we prove that for a random sequence of length L, as L is large enough, P（K） undergoes a sharp phase transition when p ≤ 0.1015 where p = P （two random letters match）. Besides, formulas are derived to estimate the transition points, which may be of practical use in sequencing DNA by hybridization. Concluded from our study, most proteins do not deviate greatly from random sequences in the sense of sequence unique reconstruction, while there are some ＂stubborn＂ proteins which only become uniquely reconstructable at a very large K and probably have biological implications.

关键词： Phase transition probability protein sequence SBh unique reconstruction

On Stability Discrimination of Limit Cycles for Piecewise Smooth Systems

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Acta Mathematica Sinica,English Series 2024年第7期40卷 1785-1803页

作者： Mao An hAN xia Yu zhou School of Mathematical Sciences Zhejiang Normal UniversityJinhua321004P.R.China

This paper is concerned with the problem of stability discrimination of limit cycles for piecewise smooth *** first establish the Poincaré map near a periodic orbit,and deduce the first order derivative of the map for general piecewise smooth systems on the ***,we obtain a sufficient condition for determining the stability of limit cycles for these systems.

关键词： Piecewise smooth system limit cycle stability

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The role of magnetic damping in the r-mode evolution of accreting neutron stars

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Science China(Physics,Mechanics & Astronomy) 2015年第3期58卷 90-95页

作者： CAO GuoJie zhou xia WANG Na Xinjiang Astronomical Observatory Chinese Academy of Sciences University of Chinese Academy of Sciences Key Laboratory of Radio Astronomy Chinese Academy of Sciences

The magnetic damping rate was introduced in the evolution equations of r-modes,which shows that r-modes can generate strong toroidal magnetic fields in the core of accreting millisecond pulsars inducing by differential *** consideration of the coupling evolution of r-modes,spin and thermal evolution,we investigated the influence of the magnetic damping on the differential rotation of nonlinear r-modes of accreting neutron *** derived the coupling evolution equations of the star involving the magnetic damping rate in the framework of second-order r-mode *** numerical results show that the magnetic damping suppressed the nonlinear evolution of r-modes since the saturation amplitude is reduced to a great *** particular,because of the presence of the generated toroidal magnetic field,the spin-down of the stars is terminated and the viscous heating effects are also ***,we could obtain a stronger generated toroidal magnetic field in the second-order r-mode *** gravitational radiation may be detected by the advanced laser interferometer detector LiGO if the amount of differential rotation is small when the r-mode instability becomes active and the accretion rate is not very high.

关键词： neutron stars r-mode instability differential rotation gravitational waves

Metal-organic frameworks with dinuclear metal centers for synergistically boosting CO2 photoreduction

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Science China Chemistry 2025年第01期 201-208页

作者： h.i-Feng Wang Wen-Jie Shi Yu-Xin Yang Bao-xia Dong Tong-Bu Lu Di-Chang Zhong School of Chemistry and Chemical Engineering Yangzhou University institute for New Energy Materials and Low Carbon Technologies School of Materials Science and Engineering Tianjin University of Technology

Dinuclear metal synergistic catalysis （DMSC） has been proved powerful in boosting CO2reduction,while this has not been achieved in heterogeneous catalysts with long-range order *** this study,we,by introduction of metal catalytic centers into an indium-based metal-organic framework （MOF）,obtained a series of isostructural in-MOFs,including three MOFs with mononuclear metal catalytic center （M-in）,three MOFs with dinuclear homometallic catalytic centers （MM-in）,and three MOFs with dinuclear heterometallic catalytic centers (MM’-in,M/M’=Co（ii）,Ni（ii）,Zn（ii）).it was found that all these MOFs can serve as catalysts for photochemical CO2reduction to *** with M-in,the catalytic activities of MM-in were obviously enhanced,and that of MM’-in was further significantly *** example,the CO yield of Co Zn-in reaches a record value of 12,700μmol g-1h-1,which.is 4.0,8.1,9.4,and 18.6-fold higher than that of Co Co-in,Zn Zn-in,Co-in,and Zn-in,***,the catalytic activities of Co Ni-in and Ni Zn-in also show different fold increase than those of corresponding dinuclear homometallic and mononuclear metallic *** results of control experiments and theoretical calculation reveal that the higher catalytic activities of MM-in over M-in can be ascribed to the DMSC effect,and the higher catalytic activity of MM’-in over MM-in can be ascribed to the strengthened DMSC *** work reveals the relationship between DMSC effect and bimetal centers in CO2reduction,which provides new insights into the DMSC and paves a new way to design highly active catalysts for photochemical CO2reduction.

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Design of integral sliding mode guidance law based on disturbance observer

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Journal of Systems Engineering and Electronics 2024年第1期35卷 186-194页

作者： zhou Jianping ZhANG Wenjie zhou hang Li Qiang xia Qunli School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China School of informatic Engineering Mianyang Techers’CollegeMianyang 62100China Beijing institute of Electronic System Engineering Beijing 100854China Beijing institute of Space Long March Vehicle Beijing 100076China

With the increasing precision of guidance,the impact of autopilot dynamic characteristics and target maneuvering abilities on precision guidance is becoming more and more *** order to reduce or even eliminate the autopilot dynamic operation and the target maneuvering influence,this paper suggests a guidance system model involving a novel integral sliding mode guidance law(iSMGL).The method utilizes the dynamic characteristics and the impact angle,combined with a sliding mode surface scheme that includes the desired line-ofsight angle,line-of-sight angular rate,and second-order differential of the angular *** the same time,the evaluation scenario considere the target maneuvering in the system as the external disturbance,and the non-homogeneous disturbance observer estimate the target maneuvering as a compensation of the guidance *** proposed system’s stability is proven based on the Lyapunov stability *** simulations reveale that iSMGL effectively intercepted large maneuvering targets and present a smaller miss-distance compared with traditional linear sliding mode guidance laws and trajectory shaping guidance ***,iSMGL has a more accurate impact angle and fast convergence speed.

关键词： disturbance observer pilot dynamics integral sliding mode impact angle constraint maneuvering target

Not vegetation itself but mis-revegetation reduces water resources

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Science China Earth Sciences 2021年第3期64卷 404-411页

作者： Guoyi zhou Jun xia Ping zhou Tingting Shi Lin Li institute of Ecology and School of Applied Meteorology Nanjing University of Information Science&TechnologyNanjing210044China State Key Laboratory of Water Resources and hydropower Engineering Science Wuhan UniversityWuhan430072China Research Center of Water Resources Chinese Academy of SciencesBeijing100101China Guangdong Open Laboratory of Geospatial information Technology and Application Guangzhou Institute of GeographyGuangdong Academy of SciencesGuangzhou510070China

increasing greening of planet Earth to slow down the rise of atmospheric CO_(2) concentrations is certainly desirable;however,its consequences on water resources are less affirmative and thus are a matter of wide ***,as the largest and most successful country of the world in terms of artificial revegetation,is naturally the focus of the concerns and *** on previous studies,we analyzed the mechanism for the effects of climate and watershed characteristics on water resources,explained various hydrological results and phenomena,and considered the ways in which water consumption by artificial revegetation projects can be ***,some guidelines are suggested for artificial revegetation at watershed scale with consideration of water resource *** findings of this study high.ight the need for more top-down approaches when studying the mechanism of"forest and water".

关键词： Greening Climate Revegetation Water resources Top-down approaches

基于混合蝙蝠智能算法优化PLSR的柑橘叶片氮含量预测方法

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西南大学学报（自然科学版） 2025年第2期47卷 160-170页

作者：刘霞周凌霄夏心杰韩如婷吕强谢让金易时来西南大学柑桔研究所/国家柑桔工程技术研究中心/国家数字种植业(柑橘)创新分中心重庆400712

高光谱成像技术具有快速、无损检测的特点,尤其在农作物生长监测方面具有广阔的应用前景。叶片氮含量是评估作物生长状况的重要指标之一,对诊断作物生长状况和制定精准施肥策略至关重要。通过获取柑橘叶片高光谱和检测叶片氮含量,探索... 详细信息

高光谱成像技术具有快速、无损检测的特点,尤其在农作物生长监测方面具有广阔的应用前景。叶片氮含量是评估作物生长状况的重要指标之一,对诊断作物生长状况和制定精准施肥策略至关重要。通过获取柑橘叶片高光谱和检测叶片氮含量,探索二者的数学关系与模型,旨在建立柑橘叶片氮含量高光谱监测技术。为提升高光谱数据建模的精度,采用了标准正态变量变换(SNV)、平滑滤波函数(SG)等方法去除光谱数据中的噪声。利用竞争自适应加权采样法(CARS)和连续投影算法(SPA)筛选出与叶片氮含量关联度高的特征波段,结合偏最小二乘回归(PLSR)、支持向量机回归(SVR)、基于遗传算法(GA)和蝙蝠算法(BA)等对PLSR进行智能优化(O-PLSR)后预测叶片氮含量。结果表明:与SVR模型相比,PLSR模型呈现更高的精度;结合GA和BA算法对PLSR模型进行优化处理,进一步提高了建模精度,相较原始PLSR模型,决定系数(R^(2))最高提高了14.8%,且经SG滤波、CRAS特征波段选取、O-PLSR优化后的模型(SG-CRAS-O-PLSR)表现出最优的估算性能,其R^(2)、均方根误差分别为0.94和0.55。由此可见,建立的SG-CARS-O-PLSR模型具有较高的精度,可为今后推进实施果园信息化与智能化精准高效施肥管理提供理论依据和技术支持。

关键词：柑橘高光谱成像技术叶片氮含量偏最小二乘回归