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2000-2020年山西省植被生长状态对气象干旱的响应

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自然资源遥感 2025年第1期37卷 221-231页

作者：赵富王莉马禹昂蒋瑞霞河南理工大学测绘与国土信息工程学院焦作454003

基于2000—2020年标准化降水指数(standardized precipitation index,SPI)与植被状态指数(vegetation condition index,VCI),采用变分模态分解(variational mode decomposition,VMD)、Mann-Kendall趋势分析、Pearson相关系数等方法,分析了山西省不同植被类型下气象干旱变化趋势,量化了植被生长状态对气象干旱的响应时间。结果表明:①20世纪以来,山西省整体气象干旱逐步缓解,但季尺度上呈现由春至冬旱情加重区不断扩大的态势;②不同植被类型下气象干旱均得到缓解,且随着时间尺度增长,态势越发显著,而季尺度上由春至冬缓解态势渐弱,加重态势渐强;③植被生长状态受气象干旱影响显著,年尺度上主要以正相关为主,季尺度上高相关性区域由春至冬逐渐收缩至西北部和东北部,而响应时间呈现出春冬长于秋夏的特征;④不同植被类型下植被生长状态对气象干旱的响应均在夏季最为迅速,且耕地是对气象干旱最敏感的地类。

关键词： SPI VCI 气象干旱响应关系山西省

焊接热输入对不同Nb含量AH36钢粗晶热影响区组织和力学性能的影响

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精密成形工程 2025年第1期17卷 134-143页

作者：潘楠王纳赵孚张宇江苏省(沙钢)钢铁研究院江苏张家港215625

目的研究大热输入条件下不同Nb含量AH36钢的焊接性能。方法使用光学显微镜、场发射扫描电镜、透射电镜、维氏硬度仪和冲击试验机,研究了热输入对不同Nb含量AH36钢粗晶热影响区(CGHAZ)微观组织、维氏硬度和常温冲击韧性的影响。采用气电... 详细信息

目的研究大热输入条件下不同Nb含量AH36钢的焊接性能。方法使用光学显微镜、场发射扫描电镜、透射电镜、维氏硬度仪和冲击试验机,研究了热输入对不同Nb含量AH36钢粗晶热影响区(CGHAZ)微观组织、维氏硬度和常温冲击韧性的影响。采用气电立焊试验评价了工业试制的AH36钢板的焊接性能。结果随着热输入的增大,原奥氏体晶粒尺寸逐渐增大,侧板条铁素体含量与贝氏体含量逐渐下降,晶界铁素体不断粗化,硬度呈现下降趋势。当热输入为140 kJ/cm时,CGHAZ的常温冲击功高于热输入80 kJ/cm时的常温冲击功,但相近于热输入200 kJ/cm时的常温冲击功。在同等热输入下低Nb钢CGHAZ的贝氏体含量小于高Nb钢的。因此,低Nb钢CGHAZ的硬度低于高Nb钢硬度,常温冲击韧性优于高Nb钢的。气电立焊接头各区域的冲击功均满足船级社要求。结论低Nb含量AH36钢的焊接性能优于高Nb含量AH36钢的。工业试制的AH36钢板具有良好的焊接性能。

关键词： Nb微合金化粗晶热影响区冲击韧性针状铁素体气电立焊

Stimulation Study of Gene Pyramiding inAnimals by Marker-Assisted Selection

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Journal of Integrative Agriculture 2012年第11期11卷 1871-1876页

作者： zhao fu-ping ZHANG Qin National Center for Molecular Genetics and Breeding of Animal Institute of Animal Sciences Chinese Academy of Agricultural Sciences Beijing 100193 P.R.China Key Laboratory of Animal Genetics Breeding and Reproduction Ministry of Agriculture/College of Animal Science and Technology China Agricultural University Beijing 100193 P.R. China

This gene pyramiding strategy is based on the idea of efficiently pyramiding genes of interest by crosses and selection to obtain a population with favorable alleles from different breeds or lines, which is called an ideal population. We investigate impacts of some factors on the pyramiding efficiencies by simulation. These factors include selection strategies （the breeding value selection, the molecular scores selection and the index selection）, proportion selected （2, 10 and 20%）, recombination rates between adjacent target genes （0.1, 0.3 and 0.5） and different mating types （the random mating and the positive assortative mating avoiding sib mating）. The results show that：（1） The more recombination rate and the lower proportion male selected, the better pyramiding efficiency; （2） the ideal population is obtained via various selection strategies, while different selection strategies are suitable for different breeding objectives. From the perspective of pyramiding target genes merely, the molecular scores selection is the best one, for the purpose of pyramiding target genes and recovering genetic background of the target trait, the index selection is the best one, while from the saving cost point of view, the breeding value selection is the best one; （3） the positive assortative mating is more efficient for gene pyramiding compared with the random mating in the terms of the number of generations of intercross for getting the ideal population.

关键词： gene pyramiding pyramiding efficiency selection strategies mating types

FBFN-based adaptive repetitive control of nonlinearly parameterized systems

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Journal of Systems Engineering and Electronics 2013年第6期24卷 1003-1010页

作者： Wenli Sun Hong Cai fu zhao School of Aerospace Science and Engineering National University of Defense Technology Beijing Aerospace Control Device Institute

An adaptive repetitive control scheme is presented for a class of nonlinearly parameterized systems based on the fuzzy basis function network （FBFN）. The parameters of the fuzzy rules are tuned with adaptive schemes. To attenuate chattering effectively, the discontinuous control term is approximated by an adaptive PI control structure. The bound of the discontinuous control term is assumed to be unknown and estimated by an adaptive mechanism. Based on the Lyapunov stability theory, an adaptive repetitive control law is proposed to guarantee the closed-loop stability and the tracking performance. By means of FBFNs, which avoid the nonlinear parameterization from entering into the adaptive repetitive control, the controller singularity problem is solved. The proposed approach does not require an exact structure of the system dynamics, and the proposed controller is utilized to control a model of permanent-magnet linear synchronous motor subject to significant disturbances and parameter uncertainties. The simulation results demonstrate the effectiveness of the proposed method.

关键词： adaptive control nonlinear parameterization repetitive control fuzzy basis function network (FBFN) permanentmagnet linear synchronous motor (PMLSM)

Magnetic Actuated Shape-memory Helical Microswimmers with Programmable Recovery Behaviors

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Journal of Bionic Engineering 2021年第4期18卷 799-811页

作者： fu zhao Weibin Rong Lefeng Wang Lining Sun State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin150080China

Inspired by bacterial flagella in nature,magnetic helical microswimmer is an ideal model to perform complex task in a low Reynolds number *** Memory Polymers(SMPs)with desirable properties are considered as one of the most preferred options for the development of small-scale ***,fabricating and programming strategies are still ***,we report an approach to fabricate helical microswimmers based on thermoplastic SMP(polylactic acid).Melt-spun polylactic acid fibers containing magnetic particles were enwound to form helical *** shape recovery behaviors were programmed by annealing and *** forms of helical microswimmers(constant-helix-angle conical helix,constant-pitch conical helix,and straight helix)with controlled morphological parameters were *** obtained microswimmers showed 3D locomotion capability under rotating magnetic *** maximum swimming velocity of microswimmers was nearly six body lengths per second,and the near-wall swimming of conical helixes along their sharp end exhibited a smaller ***,we demonstrated programmed shape-switching processes(spring-like contraction and elongation,coiling and uncoiling)and self-repairing of the *** demonstrations of potential applications,tasks of mobile microstent,cargo delivery,and minimally invasive injection were carried *** multifunctional shape-memory microswimmers have immense potential in a variety of applications.

关键词： helical microrobot magnetic actuation Shape Memory Polymer(SMP) polylactic acid magnetic particles

Existence and Uniqueness of Positive Solutions for Some Singular Boundary Value Problems with Linear functional Boundary Conditions

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Acta Mathematica Sinica,English Series 2011年第10期27卷 2073-2084页

作者： Zeng Qin zhao fu Shan LI School of Mathematical Sciences Qufu Normal University Qufu 273165 P. R. China

By using the upper and lower solution method and fixed point theory, we investigate some nonlinear singular second-order differential equations with linear functional boundary conditions. The nonlinear term f（t, u） is nonincreasing with respect to u, and only possesses some integrability. We obtain the existence and uniqueness of the C[0, 1] positive solutions as well as the C1 [0, 1] positive solutions.

关键词： Linear functional boundary condition decreasing function positive solution upper and lower solution method fixed point theorem

Integral sliding mode control of time-delay systems with mismatching uncertainties

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Journal of Systems Engineering and Electronics 2010年第2期21卷 273-280页

作者： fu zhao Yu Liu Xiuming Yao Baoku Su Space Control and Inertial Technology Research Center Harbin Institute of Technology Harbin 150001 R R. China

A linear matrix inequality （LMI）-based sliding surface design method for integral sliding mode control of uncertain time- delay systems with mismatching uncertainties is proposed. The uncertain time-delay system under consideration may have mis- matching norm bounded uncertainties in the state matrix as well as the input matrix, A sufficient condition for the existence of a sliding surface is given to guarantee asymptotic stability of the full order slJdJng mode dynamics. An LMI characterization of the slid- ing surface is given, together with an integral sliding mode control law guaranteeing the existence of a sliding mode from the initial time. Finally, a simulation is given to show the effectiveness of the proposed method.

关键词： linear matrix inequality integral sliding mode control uncertain time-delay systems mismatching uncertainties.

Robust H_∞ filtering for discrete-time systems with Markovian switching and time-delays

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Journal of Systems Engineering and Electronics 2009年第5期20卷 1072-1080页

作者： Yao Xiuming zhao fu Ling Mingxiang Wang Changhong Space Control and Inertia Technology Research Center Harbin Inst. of Technology Harbin 150001 P. R. China School of Science and Engineering North China Electric Power Univ. Beijing 102206 P. R. China

The robust H∞ filtering problem for uncertain discrete-time Markovian jump linear systems with mode- dependent time-delays is investigated. Attention is focused on designing a Markovian jump linear filter that ensures robust stochastic stability while achieving a prescribed H∞ performance level of the resulting filtering error system, for all admissible uncertainties. The key features of the approach include the introduction of a new type of stochastic Lyapunov functional and some free weighting matrix variables. Sufficient conditions for the solvability of this problem are obtained in terms of a set of linear matrix inequalities. Numerical examples are provided to demonstrate the reduced conservatism of the proposed approach.

关键词： discrete-time Markovian jump linear system robust H∞ filtering mode-dependent delay linear matrix inequality.

The Historical Re-Brightening and Distance Recheck of SN 1006

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Chinese Journal of Astronomy and Astrophysics 2007年第2期7卷 325-328页

作者： Shi-Yang Jiang fu-Yuan zhao National Astronomical Observatory Chinese Academy of Sciences Beijing 100012

We presume the re-brightening of SN 1006 in AD 1016 as recorded in the ancient Chinese literature to be true and the re-brightening was caused by the encounter either of photons or the shock wave from the SN outburst with the circumstellar thin envelope materials. Based on these considerations, and combining the observational results on the optical proper motion of the N-W limb and the radio observations of the other parts of the supernova remnant G327.6＋14.5, we re-determine the distance to SN 1006. For the photon-encounter model, the average radius of the envelope material would be 101y; and for the shock waveencounter model, the radius would be about 1 ly. We then set up four equations to solve for the distance of the SN, the initial shock speed, the expansion index for two different parts of the supernova remnant, and the real original radius of the thin envelope nebula. It is indicated that only the case of photon-encounter will lead to a reasonable result. We derived a distance of 5074 ly （1.56 kpc）, an original shock expansion velocity of 0.07 1c, an expansion index of 0.72 for the N-W limb of the SNR, and 0.76 for the other parts. We deem that the SNR evolution is still in the stage of reverse shock.

关键词： supernova supernova remnant -SN 1006 distance- Zhou-Bo Star -plan-etary nebula