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Spatiotemporal dynamics of the urban sprawl in a typical urban agglomeration： a case study on Southern Jiangsu, China （1983-2007）

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Frontiers of Earth Science 2014年第4期8卷 490-504页

作者： Yongxue LIU Jieli CHEN wangyu cheng Chao SUN Saishuai ZHAO Yingxia PU School of Geographic and Oceanographic Sciences Nanjing University Nanjing 210093 China Changzhou Land and Resources Administration Wujin District Branch Changzhou 213161 China

China has experienced urbanization at an unprecedented rate over the past decades. Against this background, this paper demonstrates the multi-level spatiotemporal urban sprawl process from 1983 to 2007 on the perspective of urban agglomeration with a case study in Southern Jiangsu. Based on a combination of eight rounds of satellite images from 1983 to 2007, the presented results suggest the following three main findings：（1） At the prefecture-city level, the urban sprawl in Southern Jiangsu has presented significantly divergent growth patterns, with more than half of this vast growth occurring in the Suzhou prefecture-level city. （2） At the county level, clear spatial differentiations exist in the direction of the urban sprawl. The centroids of all county seats in the Suzhou and Wuxi prefecture-level cities have an eastward tendency （Shanghai oriented）, while those of the county seats in the Changzhou prefecture-level city tend to be westward （Nanjing oriented）. （3） At the township level, two convergent groups have gradually formed over time; namely, the low density urban zone in the western hilly land and the high density urban zone around the three central downtown areas. The urban areas close to urban cores tend to merge, showing a high-density convergent growth pattern, as do the western and southwestern townships in Southern Jiangsu, showing a low-density convergent growth pattern. All of these findings may be valuable for researchers and local authorities in providing reference for regional coordinated growth, environmental management, and urban planning decision-making.

关键词： Southem Jiangsu urban sprawl spatiotemporal dynamics rapid urbanization areas

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基于Landsat遥感影像的海上油气平台提取与监测

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热带地理 2017年第1期37卷 112-119页

作者：赵赛帅孙超王海江成王玉宁波市阿拉图数字科技中心浙江宁波315040 南京大学中国南海研究协同创新中心南京210023 宁波市测绘设计研究院浙江宁波315040 国家测绘地理信息局第一航测遥感院陕西西安710054

监测海上油气平台的开发有着巨大的经济和军事意义。针对可见光遥感影像数据源丰富的特性,提出了一种适用于Landsat系列中等分辨率的光学影像的海上油气平台的提取监测方法。首先将TM/ETM+/OLI影像进行几何校正、辐射校正、图像增强以... 详细信息

监测海上油气平台的开发有着巨大的经济和军事意义。针对可见光遥感影像数据源丰富的特性,提出了一种适用于Landsat系列中等分辨率的光学影像的海上油气平台的提取监测方法。首先将TM/ETM+/OLI影像进行几何校正、辐射校正、图像增强以及区域掩膜等系列预处理,其次采用多滑动窗口动态阈值遍历影像初步识别疑似油气平台,然后应用相邻时期3景影像基于像素级别的叠合判定以去除薄云以及舰船的虚警干扰,筛选出最终的油气平台,以马来西亚与文莱交界的南海海域为实验区,通过1991―2016年共21景Landsat影像,动态监测该区域近25 a来油气平台开发的历史过程,共检测66个油气平台,通过与ALOS PALSAR数据人工识别的油气平台进行对比验证,结果表明:该方法提取的检测率为82.67%,正确率达到86.11%。监测结果显示:该海域油气平台开发主要集中在20世纪90年代之前,而后近海油气新增开发平台较少,开发主要向远离陆地的深海方向扩展。

关键词：遥感油气平台影像识别滑动窗口南海海域

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Bilinear magnetoelectric resistance induced by spin Hall effect

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Science China Materials 2025年第2期68卷 687-688页

作者： Ruiyue Chu cheng Song School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China

Magnetoresistance(MR)is a fundamental transport phenomenon crucial for reading magnetic *** also plays a key role in understanding how time-reversal symmetry breaking affects electrical *** discoveries of anisotropic MR[1],giant MR[2],tunneling MR[3],and spin Hall magnetoresistance[4]have driven the development of diverse spintronic devices used in data storage,computing,and sensing ***,these MR effects do not scale linearly with the electric field(and thus,electric current).Recently,nonlinear MR,which scales specifically with the electric current(Ic),has been *** magnetic/non-magnetic bilayers,unidirectional spin Hall magnetoresistance(USMR)[5]shows a linear dependence on Ic,with voltage scaling quadratically with the applied electric field,due to interfacial spin-dependent and electron-magnon scattering mechanisms.

关键词： breaking symmetry linearly

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Control of Corner Separation for a Linear Compressor Cascade via Bionic Slanting Riblets at the Endwall

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Journal of Thermal Science 2025年第1期34卷 129-144页

作者： ZHANG Peng LI Yonghong cheng Rixin Key Laboratory of Civil Aircraft Airworthiness Technology Civil Aviation University of ChinaTianjin 300300China College of Aeronautical Engineering Civil Aviation University of ChinaTianjin 300300China

A new passive control approach,utilizing bionic slanting riblets,is employed to mitigate the flow close to the blade endwall in a linear cascade,and its effectiveness and mechanism in controlling corner separation are investigated through numerical *** slanting riblets are positioned at the endwall upstream of the cascade channel,and the influence of riblet height,yaw angle and relative position on the control of corner separation is *** findings indicate that the application of slanting riblets can efficiently counteract corner separation across the stable operational ***,the introduction of riblets with a height of merely 0.1 times the boundary layer thickness results in a significant reduction in total pressure loss by up to 14.53%,while simultaneously enhancing the static pressure coefficient by 21.74%.Flow analysis reveals that minute vortices produced within the riblet channels tend to coalesce,forming a potent large-scale vortex near the boundary layer's base *** phenomenon results in reduced additional losses compared to conventional vortex ***,the induced vortex promotes enhanced mixing between the mainstream flow and boundary layer,inhibiting the lateral displacement of low-energy fluids within the endwall boundary ***,this delays the onset of separation vortex formation and eliminates vortex rings in the corner region,ultimately enhancing the aerodynamic efficiency of the cascade.

关键词： corner separation compressor cascade slanting riblets additional losses vortex generator

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Theoretical calculation on degradation mechanism of novel copolyesters under CALB enzyme

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Journal of Environmental Sciences 2025年第3期149卷 242-253页

作者： Yuanyang Ren Zhiwen cheng Luwei cheng Yawei Liu Mingyue Li Tao Yuan Zhemin Shen School of Environmental Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China State Environmental Protection Key Laboratory of Environmental Health Impact Assessment of Emerging Contaminants Shanghai 200240China Shanghai Institute of Pollution Control and Ecological Security Shanghai 200092China

Poly(butylene succinate-co-furandicarboxylate)(PBSF)and poly(butylene adipateco-furandicarboxylate)(PBAF)are novel furandicarboxylic acid-based biodegradable copolyesters with great potential to replace fossil-derived terephthalic acid-based copolyesters such as poly(butylene succinate-co-terephthalate)(PBST)and poly(butylene adipate-co-terephthalate)(PBAT).In this study,quantum chemistry techniques after molecular dynamics simulations are employed to investigate the degradationmechanism of PBSF and PBAF catalyzed by Candida antarctica lipase B(CALB).Computational analysis indicates that the catalytic reaction follows a four-step mechanism resembling the ping-pong bibi mechanism,with the initial two steps being acylation reactions and the subsequent two being hydrolysis ***,the first step of the hydrolysis is identified as the rate-determining ***,by introducing single-point mutations to expand the substrate entrance tunnel,the catalytic distance of the first acylation step ***,energy barrier of the rate-determining step is decreased in the PBSF system by site-directed mutations on key residues increasing hydrophobicity of the enzyme’s active *** study unprecedently show the substrate binding pocket and hydrophobicity of the enzyme’s active site have the potential to be engineered to enhance the degradation of copolyesters catalyzed by CALB.

关键词： Poly(butylene succinate-co-furandicarboxylate) Poly(butylene adipate-co-furandicarboxylate) Candida antarctica lipase B Degradation mechanism Site-directed mutations

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The shadow and gamma-ray bursts of a Schwarzschild black hole in asymptotic safety

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Communications in Theoretical Physics 2025年第2期77卷 121-131页

作者： Yuxuan Shi Hongbo cheng Department of Physics East China University of Science and Technology The Shanghai Key Laboratory of Astrophysics

The effects and rules of the dimensionless parameter ξ on neutrino annihilation v+■→e-+e+dominated gamma-ray bursts are analysed and investigated within the context of black holes in asymptotic *** also computationally model photon orbits around black holes,as photons and neutrinos have the same geodesic equations near black *** show that the black hole shadow radius decreases with increasing ξ.Calculations are made to determine the temperature of the accretion disk surrounding the black hole and the ratio ■Newtof energy deposition per unit time and compared to that of the Newtonian *** accretion disk temperature peaks at a higher temperature due to quantum gravity corrections,which increases the probability of neutrino emission from the black *** is interesting to note that larger quantum gravity effects cause the ratio value to significantly *** the neutrinoantineutrino annihilation process,the energy deposition rate is sufficient even while the energy conversion is inhibited because of quantum ***-ray bursts might originate from the corrected annihilation ***,we examine the derivative d■/dr about the star radius *** findings demonstrate that the ratio is lowered by the black hole's quantum *** neutrino pair annihilation grows weaker the more prominent the influence of quantum gravity.

关键词： quantum gravity black hole gamma-ray burst

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Mode-switching cooperative defense strategy for the orbit pursuit-evasion-defense game

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Defence Technology(防务技术) 2025年第2期44卷 272-286页

作者： Yongshang Wei Tianxi Liu cheng Wei School of Aerospace Harbin Institute of TechnologyHarbin150000China

This paper presents a mode-switching collaborative defense strategy for spacecraft pursuit-evasiondefense *** these scenarios,the pursuer tries to avoid the defender while capturing the evader,while the evader and defender form an alliance to prevent the pursuer from achieving its ***,the behavioral modes of the pursuer,including attack and avoidance modes,were established using differential game *** modes are then recognized by an interactive multiple model-matching algorithm(IMM),that uses several smooth variable structure filters to match the modes of the pursuer and update their probabilities in real *** on the linear-quadratic optimization theory,combined with the results of strategy identification,a two-way cooperative optimal strategy for the defender and evader is proposed,where the evader aids the defender to intercept the pursuer by performing luring *** results show that the interactive multi-model algorithm based on several smooth variable structure filters perform well in the strategy identification of the pursuer,and the cooperative defense strategy based on strategy identification has good interception performance when facing pursuers,who are able to flexibly adjust their game objectives.

关键词： Cooperative policy Differential games Orbit pursuit-evasion-defense game Mod recognition

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On Halmos'third problem on Banach spaces

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Science China Mathematics 2025年第2期68卷 399-420页

作者： Lixin cheng Junsheng Fang Chunlan Jiang School of Mathematical Sciences Xiamen UniversityXiamen 361005China School of Mathematical Sciences Hebei Normal UniversityShijiazhuang 050016China

In 1970,Halmos posed ten open problems in Hilbert *** third problem asks:If an intransitive operator T has an inverse,is its inverse also intransitive?This question is closely related to the invariant subspace *** Enflo's celebrated counterexample on l_(1)provided a negative answer to the invariant subspace problem,the Banach space version of Halmos'third problem has attracted increasing *** this paper,we provide an affirmative answer to this problem under certain spectral *** an application,we show that for an invertible operator T with Dunford's property(C),if T-1is intransitive and there exists a connected componentΩof intσ(T-1)^(^)off the origin and satisfiesΩ∩ρF(T-1)≠φ,then T is also ***,we show that a necessary and sufficient condition for the existence of a bounded linear operator without nontrivial invariant subspaces on the infinite-dimensional space L1(Ω,Σ,μ)(resp.C(K),the space of bounded continuous functions on a complete metric space K)is that(Ω,Σ,μ)isσ-finite(resp.K is compact).

关键词： invariant subspace bounded linear operator Banach space

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Three-dimensional fracture of UO_(2)ceramic pellets by phase field modeling

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Science China(Physics,Mechanics & Astronomy) 2025年第1期68卷 165-176页

作者： Wei Xiong Xuan Ye Hongzhang cheng Xiaoming Liu Institute of Nuclear and New Energy Technology Collaborative Innovation Center of Advanced Nuclear Energy TechnologyKey Laboratory of Advanced Reactor Engineering and Safety of Ministry of EducationTsinghua UniversityBeijing 100084China State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China

Fracture is the primary failure type for the UO_(2)ceramic pellets,which are operated under irradiation and thermal processes,and physically confined by the *** this work,by combining closely coupled physical processes of heat conduction,heat transfer,and mechanical deformation with the cohesive phase field framework,we proposed a high-precision modeling of quasistatic cracking of three-dimensional(3D)UO_(2)ceramic fuel pellets under high temperature and *** simulation results agree well with the experimental results,indicating that the proposed method has the potential to capture 3D crack modes in the interested time ***,we studied the relation of the 3D fracture patterns of fuel pellets with the peak power *** was found that the power level plays a critical role in determining the competition between radial and circumferential cracks,as well as transverse penetrating cracks.

关键词： phase field method nuclear fuel pellet coupled thermo-mechanical model thermal fracture

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Axial emission characteristics of an ionic liquid electrospray thruster with a circular emitter

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Chinese Journal of Aeronautics 2025年第1期38卷 297-305页

作者： cheng YANG Jiawei LUO Xiangbei WU Yan SHEN School of Aeronautics and Astronautics Sun Yat-sen UniversityShenzhen 518107China Shenzhen Key Laboratory of Intelligent Microsatellite Constellation Shenzhen 518107China

Ionic Liquid Electrospray Thrusters(ILETs)are well suited for micro-nano satellite applications due to their small size,low power consumption,and high specific ***,the limited thrust of a single-emitter ILET restricts its use in space *** optimize the performance of ILETs and make them suitable for a wider range of space missions,we designed a Circular-emitter ILET(CILET)to convert a one-dimensional(point)emission into a twodimensional(line)*** CILET can self-organize multiple Taylor cones *** cones were photographed and the axial emission currents were measured under different voltage and pressure difference conditions with a CILET experimental *** emission can be divided into two stable states and one unstable state based on the flow and current *** current in Stable state Ⅰ increases non-linearly with the voltage,while that in Stable state Ⅱ is nearly linear with respect to the *** number of cones increases with the voltage in stable states,while the cones become short and crowded under high-voltage *** variation law of the number of cones can be explained with the self-organization *** variation in the current exhibits a good correlation with the number of *** study demonstrates the feasibility of circular emitters and experimentally indicates that the emission current is improved by approximately two orders of magnitude compared to that of a single capillary.

关键词： Electrospray Ionic liquid thruster Self-organize Emitter Taylor cone

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