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Spatial-temporal heterogeneity of ecological quality changes across the Qinghai-Tibet Plateau under the influence of climate factors and human activities

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Research in Cold and Arid Regions 2024年第3期16卷 129-140页

作者： ZiPing Zhang YuWei Cui WenJia Tang sen li Qinghai Province Ecological and Environmental Monitoring Center XiningQinghai 810007China Key Laboratory of Desert and Desertification Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhouGansu 730000China University of Chinese Academy of Sciences Beijing 100049China

Over the last few decades,the ecological quality of the Qinghai–Tibet Plateau(QTP)has significantly changed due to climate warming,humidification,and increasing human ***,evaluating this region's ecological quality and dominant factors is crucial for sustainable *** this study,the changes in the ecological quality on the QTP from 2000 to 2020 were evaluated based on aggregated indices and sen–MK trend analyses,and the dominant factors affecting the ecological quality of the QTP were quantitatively analyzed using decision tree *** results revealed that(1)the ecological quality of the QTP exhibited an overall high trend in the east and a low pattern in the west;(2)the ecological quality of the QTP significantly increased from 2000 to 2020,and human activities were the dominant factors causing this change;and(3)the changes in the ecological quality and dominant factors exhibited obvious spatiotemporal *** area with an improved ecological quality occurred mainly in the northern QTP *** was governed by human activities and *** contrast,the area with a deteriorated ecological quality occurred largely in the southern QTP region and was dominated by human activities and *** 2000–2010 period was the most significant period of heterogeneity regarding of ecological quality and its driving factors.(4)The change in the ecological quality was mainly affected by the synergistic relationship between human activities and climate change in this region,which encompassed multiple dominant *** study provides important information on the spatiotemporal heterogeneity of ecological quality change and its dominant factors on the QTP and offers systematic guidance for the planning and implementation of ecological protection projects.

关键词： Remote sensing-based ecological index(RSEI) Dominant factors Synergies and trade-offs Qinghai‒Tibet Plateau

Multi-Level Image Segmentation Combining Chaotic Initialized Chimp Optimization Algorithm and Cauchy Mutation

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Computers, Materials & Continua 2024年第8期80卷 2049-2063页

作者： Shujing li Zhangfei li Wenhui cheng Chenyang Qi linguo li School of Computer and Information Engineering Fuyang Normal UniversityFuyang236041China

To enhance the diversity and distribution uniformity of initial population,as well as to avoid local extrema in the Chimp Optimization Algorithm(CHOA),this paper improves the CHOA based on chaos initialization and Cauchy ***,Sin chaos is introduced to improve the random population initialization scheme of the CHOA,which not only guarantees the diversity of the population,but also enhances the distribution uniformity of the initial ***,Cauchy mutation is added to optimize the global search ability of the CHOA in the process of position(threshold)updating to avoid the CHOA falling into local ***,an improved CHOA was formed through the combination of chaos initialization and Cauchy mutation(CICMCHOA),then taking fuzzy Kapur as the objective function,this paper applied CICMCHOA to natural and medical image segmentation,and compared it with four algorithms,including the improved Satin Bowerbird optimizer(ISBO),Cuckoo Search(ICS),*** experimental results deriving from visual and specific indicators demonstrate that CICMCHOA delivers superior segmentation effects in image segmentation.

关键词： Image segmentation image thresholding chimp optimization algorithm chaos initialization Cauchy mutation

Flame-retardant ammonium polyphosphate/MXene decorated carbon foam materials as polysulfide traps for fire-safe and stable lithium-sulfur batteries

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Journal of Energy Chemistry 2024年第2期89卷 313-323,I0008页

作者： Yang li Yong-cheng Zhu Sowjanya Vallem Man li Seunghyun Song Tao Chen Long-cheng Tang Joonho Bae Department of Physics Gachon UniversitySeongnam-siGyeonggi-do 13120South Korea Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education College of MaterialChemistry and Chemical EngineeringHangzhou Normal UniversityHangzhou 311121ZhejiangChina Key laboratory of Advanced Energy Materials Chemistry(Ministry of Education) College of ChemistryNankai UniversityTianjin 300071China School of Materials Engineering Changzhou Vocational Institute of Industry TechnologyChangzhou 213164JiangsuChina

lithium-sulfur(li-S)batteries are one of the most promising modern-day energy supply systems because of their high theoretical energy density and low ***,the development of high-energy density li-S batteries with high loading of flammable sulfur faces the challenges of electrochemical performance degradation owing to the shuttle effect and safety issues related to fire or explosion *** this work,we report a three-dimensional(3D)conductive nitrogen-doped carbon foam supported electrostatic self-assembled MXene-ammonium polyphosphate(NCF-MXene-APP)layer as a heat-resistant,thermally-insulated,flame-retardant,and freestanding host for li-S batteries with a facile and costeffective synthesis ***,through the use of NCF-MXene-APP hosts that strongly anchor polysulfides,the li-S batteries demonstrate outstanding electrochemical properties,including a high initial discharge capacity of 1191.6 mA h g^(-1),excellent rate capacity of 755.0 mA h g^(-1)at 1 C,and long-term cycling stability with an extremely low-capacity decay rate of 0.12%per cycle at 2 *** importantly,these batteries can continue to operate reliably under high temperature or flame attack ***,this study provides valuable insights into the design of safe high-performance li-S batteries.

关键词： Flame-retardant MXene Ammonium polyphosphate Safety lithium-sulfur battery

Iron oxide/CNT-based artificial nacre for electromagnetic interference shielding

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Nano Research 2024年第7期17卷 6560-6566页

作者： cheng-Xin Yu Yu-Feng Meng Bo Yang Jun Pang Xiang-sen Meng Zi-Ye Zhao Qing-Yue Wang li-Bo Mao Zhi-Kun Wu Shu-Hong Yu Institute of Physical Science and Information Technology Anhui UniversityHefei 230601China Key Laboratory of Materials Physics Anhui Key Laboratory of Nanomaterials and NanotechnologyCAS Center for Excellence in NanoscienceInstitute of Solid State PhysicsHFIPSChinese Academy of SciencesHefei 230031China Department of Chemistry New Cornerstone Science LaboratoryInstitute of Biomimetic Materials&ChemistryAnhui Engineering Laboratory of Biomimetic MaterialsDivision of Nanomaterials&ChemistryHefei National Research Center for Physical Sciences at the MicroscaleUniversity of Science and Technology of ChinaHefei 230026China

Biological structural materials,despite consisting of limited kinds of compounds,display multifunctionalities due to their complex hierarchical *** some biomimetic strategies have been applied in artificial materials to enhance their mechanical stability,the simultaneous optimization of other functions along with the mechanical properties via biomimetic designs has not been thoroughly ***,iron oxide/carbon nanotube(CNT)-based artificial nacre with both improved mechanical and electromagnetic interference(EMI)shielding performance is fabricated via the mineralization of Fe_(3)O_(4)onto a CNTincorporated *** micro-and nano-structures of the artificial nacre are similar to those of natural nacre,which in turn improves its mechanical *** alternating electromagnetic wave-reflective CNT layers and the wave-absorptive iron oxide layers can improve the multiple reflections of the waves on the surfaces of the reflection layers,which then allows sufficient interactions between the waves and the absorption ***,compared with the reflection-dependent EMI-shielding of the non-structured material,the artificial nacre exhibits strong absorption-dependent shielding behavior even with a very low content of wave-absorptive *** to the high mechanical stability,the shielding effectiveness of the artificial nacre that deeply cut by a blade is still maintained at approximately 70%−96%depending on the incident wave *** present work provides a new way for designing structural materials with concurrently enhanced mechanical and functional properties,and a path to combine structural design and intrinsic properties of specific materials via a biomimetic strategy.

关键词： artificial nacre electromagnetic interference shielding biomineralization biomimetic material hierarchical structure

Complex-frequency waves:beat loss and win sensitivity

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light(Science & Applications) 2024年第2期13卷 181-183页

作者： Qingqing cheng Tao L School of Optical-Electrical and Computer Engineering University of Shanghai for Science and TechnologyShanghai200093China Department of Respiratory Diseases and Critical Medicine Quzhou Hospital Affiliated to Wenzhou Medical UniversityQuzhou324000China National Laboratory of Solid State Microstructures College of Engineering and Applied SciencesNanjing UniversityNanjing210093China

Recent experiments have demonstrated that synthesized complex-frequency waves can impart a virtual gain to molecule sensing systems,which can effectively restore information lost due to intrinsic molecular *** enhancement notably amplifies the signal of trace molecular vibrational fingerprints,thereby substantially improving the upper limit of sensitivity.

关键词： thereby Complex limit

Thyristor-inserted MMC Sub-module Topology with DC Fault Blocking Capability

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CSEE Journal of Power and Energy Systems 2024年第5期10卷 2221-2229页

作者： cheng Peng Rui li Xu Cai Key Laboratory of Control of Power Transmission and Conversion Shanghai Jiao Tong UniversityMinistry of EducationShanghai Jiao Tong UniversityShanghai 200240China.

Modular multilevel converter(MMC)is increasingly being applied to high voltage direct current(HVDC)***,dc short circuit situations restrain the application of a conventional half bridge MMC *** this paper,a new sub-module topology with inserted thyristor can help the MMC system clear a dc side *** states and devices voltage stress of the proposed topology are analyzed and the conduction loss comparison between the proposed topology with several existing topologies with dc fault blocking capability is carried *** show the proposed topology is superior to other topologies in terms of conduction loss while using the same voltage rating ***,compared with traditional half bridge topology,only thyristors and diodes are added in the proposed ***,cost of the proposed topology can be lower than conventional hybrid MMC *** last,the fault blocking capability of the proposed topology is verified in the simulation.

关键词： Fault current limiting high voltage direct current(HVDC)transmission modular multilevel converter(MMC)

Double stabilizations and convergence analysis of a second-order linear numerical scheme for the nonlocal Cahn-Hilliard equation

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Science China Mathematics 2024年第1期67卷 187-210页

作者： Xiao li Zhonghua Qiao cheng Wang Department of Applied Mathematics The Hong Kong Polytechnic UniversityHong KongChina Department of Mathematics The University of MassachusettsNorth DartmouthMA 02747USA

In this paper,we study a second-order accurate and linear numerical scheme for the nonlocal CahnHilliard *** scheme is established by combining a modified Crank-Nicolson approximation and the Adams-Bashforth extrapolation for the temporal discretization,and by applying the Fourier spectral collocation to the spatial *** addition,two stabilization terms in different forms are added for the sake of the numerical *** conduct a complete convergence analysis by using the higher-order consistency estimate for the numerical scheme,combined with the rough error estimate and the refined *** regarding the numerical solution as a small perturbation of the exact solution,we are able to justify the discrete?^(∞)bound of the numerical solution,as a result of the rough error ***,the refined error estimate is derived to obtain the optimal rate of convergence,following the established?∞bound of the numerical ***,the energy stability is also rigorously proved with respect to a modified *** proposed scheme can be viewed as the generalization of the second-order scheme presented in an earlier work,and the energy stability estimate has greatly improved the corresponding result therein.

关键词： nonlocal Cahn-Hilliard equation second-order stabilized scheme higher-order consistency analysis rough and refined error estimate

Formation of Superthin Galaxies in IllustrisTNG

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Research in Astronomy and Astrophysics 2024年第7期24卷 235-248页

作者： Jianhong Hu Dandan Xu cheng li Department of Astronomy Tsinghua UniversityBeijing 100084China

Superthin galaxies are observed to have stellar disks with extremely small minor-to-major axis *** this work,we investigate the formation of superthin galaxies in the TNG100 *** trace the merger history and investigate the evolution of galaxy properties of a selected sample of superthin galaxies and a control sample of galaxies that share the same joint probability distribution in the stellar-mass and color *** making comparisons between the two galaxy samples,we find that present-day superthin galaxies had similar morphologies as the control sample counterparts at higher redshifts,but have developed extended flat“superthin”morphologies since z~*** this latter evolution stage,superthin galaxies undergo an overwhelmingly higher frequency of prograde mergers(with orbit-spin angleθ_(orb)≤40°).Accordingly the spins of their dark matter halos have grown significantly and become noticeably higher than those of their normal disk *** further results in the buildup of their stellar disks at larger distances much beyond the regimes of normal disk *** also discuss the formation scenario of those superthin galaxies that live in larger dark matter halos as satellite galaxies therein.

关键词： Galaxies formation-Galaxies evolution-Galaxies interactions-Galaxies star formation

Current status of early gastric cancer screening research

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Cancer Biology & Medicine 2024年第3期21卷 218-222页

作者： Can Hu li Yuan Xiangdong cheng Department of Gastric surgery Zhejiang Cancer HospitalHangzhou Institute of Medicine(HIM)Chinese Academy of SciencesHangzhouZhejiang 310022China Key Laboratory of Prevention Diagnosis and Therapy of Upper Gastrointestinal Cancer of Zhejiang ProvinceHangzhou 310022China Zhejiang Provincial Research Center for Upper Gastrointestinal Tract Cancer Zhejiang Cancer HospitalHangzhou 310022China

Gastric cancer is a predominant threat to the health and well-being of China's residents. Data from the World Health Organization(WHO) in 2020 revealed that gastric cancer in China notably accounted for 44.0% of new c... 详细信息

关键词： cancer Gastric gastric