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Preparation of Self-limiting Heating Cables with Excellent Processability, Mechanical Properties and PTC Effect via Thermal and Electrical Treatments

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Chinese Journal of Polymer Science 2024年第4期42卷 511-520页

作者： tian-Hao Yang Tong wu Qiang Fu State Key Laboratory of Polymer Materials Engineering College of Polymer Science and EngineeringSichuan UniversityChengdu610065China State Key Laboratory of Polymer Materials Engineering Polymer Research Institute of Sichuan UniversityChengdu610065China

Polymer/conductive filler composites have been widely used for the preparation of self-limiting heating cables with the positive temperature coefficient (PTC) effect. The control of conductive filler distribution and network in polymer matrix is the most critical for performance of PTC materials. In order to compensate for the destruction of the filler network structure caused by strong shearing during processing, an excessive conductive filler content is usually added into the polymer matrix, which in turn sacrifices its processability and mechanical properties. In this work, a facile post-treatment of the as-extruded cable, including thermal and electrical treatment to produce high-density polyethylene (HDPE)/carbon black (CB) cable with excellent PTC effect, is developed. It is found for the as-extruded sample, the strong shearing makes the CB particles disperse uniformly in HDPE matrix, and 25 wt% CB is needed for the formation of conductive paths. For the thermal-treated sample, a gradually aggregated CB filler structure is observed, which leads to the improvement of PTC effect and the notable reduction of CB content to 20 wt%. It is very interesting to see that for the sample with combined thermal and electrical treatment, CB particles are agglomerated and oriented along the electric field direction to create substantial conductive paths, which leads to a further decrease of CB content down to 15 wt%. In this way, self-limiting heating cables with excellent processability, mechanical properties and PTC effect have simultaneously been achieved.

关键词： Self-limiting heating cables Positive temperature coefficient Thermal treatment Electrical treatment

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Optimal Risk Sharing for Maxmin Choquet Expected Utility Model

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Acta Mathematicae Applicatae Sinica 2024年第2期40卷 430-444页

作者： De-jian tian Shang-ri wu School of Mathematics China University of Mining and TechnologyXuzhou 221116China

This article analyzes the Pareto optimal allocations,agreeable trades and agreeable bets under the maxmin Choquet expected utility(MCEU)*** provide several useful characterizations for Pareto optimal allocations for risk averse *** derive the formulation descriptions for non-existence agreeable trades or agreeable bets for risk neutral *** build some relationships between ex-ante stage and interim stage on agreeable trades or bets when new information arrives.

关键词： maxmin Choquet expected utility model Pareto optimal allocation agreeable trade agreeable bet

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Cycling performance of layered oxide cathode materials for sodium-ion batteries

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International Journal of Minerals,Metallurgy and Materials 2024年第7期31卷 1720-1744页

作者： Jinpin wu Junhang tian Xueyi Sun Weidong Zhuang School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China Beijing Key Laboratory for Green Recovery and Extraction of Rare and Precious Metals University of Science and Technology BeijingBeijing 100083China

Layered oxide is a promising cathode material for sodium-ion batteries because of its high-capacity,high operating voltage,and simple *** performance is an important criterion for evaluating the application prospects of ***,facing challenges,including phase transitions,ambient stability,side reactions,and irreversible anionic oxygen activity,the cycling performance of layered oxide cathode materials still cannot meet the application ***,this review proposes several strategies to address these ***,bulk doping is introduced from three aspects:cationic single doping,anionic single doping,and multi-ion ***,homogeneous surface coating and concentration gradient modification are *** addition,methods such as mixed structure design,particle engineering,high-entropy material construction,and integrated modification are ***,a summary and outlook provide a new horizon for developing and modifying layered oxide cathode materials.

关键词： sodium-ion battery layered oxide materials cycling performance bulking doping surface coating concentration gradient mixed structure high-entropy

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Characteristics and potential analysis of Madagascar hydrocarbon-bearing basins

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China Geology 2019年第1期2卷 56-66页

作者： da-tian wu Johanne Iomimalala Ramaniraka Feng-ming Xu Jian-bo Shao Yong-heng Zhou Yuan-dong Zhao Bruno Ralison Shenyang Center China Geological SurveyMinistry of Natural ResourcesShenyang 110034China China University of Geosciences Wuhan 430074China Departement des Sciences de la Terre Faculte des SciencesUniversite d’AntananarivoAntananarivo 101Madagascar

Madagascar becomes a large isolated island after its dislocation from East Africa at its western part during the opening of the Mozambique Channel and its separation from India at its eastern part during the opening of the basin of the Mascarene. From a stratigraphic point of view, Karroo of Madagascar shares substantial similarities with the stratigraphic strata of East *** oil companies have taken a liking to the basins of East Africa, they also turn to the basins in the western part of Madagascar especially after the discovery of large oil fields at Tsimiroro and Bemolanga. According to the study of their geological history, the basins of Madagascar contain huge hydrocarbon potential. The western basins, which is more developed than the east coast of the island, have been the subject of many in-depth studies by numerous researchers. The cross-referencing of bibliographic data with geological studies, and knowledge of hydrocarbon formation and maturation stages, carried out in this study served to determine the nature of source rocks, reservoir rocks, bedrock and eventual trapping system of hydrocarbons in Madagascar. This study identified the properties of Madagascar source rocks, reservoir rocks, bedrock and the final oil and gas trap system by cross-referencing the literature and geological research, oil and gas formation and maturity stages, and shows that Madagascar has considerable hydrocarbon potential.

关键词： Madagascar Hydrocarbon-bearing basins Characteristics of Malagasy basins Potential analysis Geology and stratigraphy

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Flame Synthesis of Zr/ZSM-5 Catalysts with Tunable Acidity for the Oxidative Dehydrogenation of Propane to Propene

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Journal of Thermal Science 2024年第1期33卷 268-283页

作者： daNIEL Samuel FONZEU MONGUEN Cedric Karel wu Lingnan tian Zhenyu Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Tuning the surface acidity of ZSM-5 catalyst is essential to achieve desired propene selectivity and *** several ratios of Zr were utilized to modify ZSM-5 via flame spray pyrolysis technique coupled with a pulse spray evaporation *** interaction between Zr and ZSM-5 in the flame influenced the physicochemical and acidity properties of the Zr/*** increasing Zr ratio in ZSM-5 shows coated layers of irregular nano-sized Zr with an increase in crystallite sizes due to the synergetic effect between Zr and *** surface chemical analysis revealed increased lattice oxygen on the Zr modified ZSM-5(1:4) sample compared to other *** acidity analysis revealed the Lewis and Br?nsted acid distribution in the weak and medium acid sites on the catalyst ***,the increase in Zr loading decreased the concentration of Br?nsted acid sites and tuned the catalyst surface to more Lewis acidity,promoting propene selectivity and hindering the over-oxidation of *** modified ZSM-5 catalysts were examined in a fixed bed reactor within 300℃-700℃ at a gas hourly space velocity(GHSV) of 6000 mL·g(catalysts)^(-1)·h^(-1) for the oxidative dehydrogenation of propane(ODHP) to *** the catalysts,Zr/ZSM-5(1:4) exhibited the best propene yield, with 57.19% propane conversion and 75.54% selectivity to propene and the highest *** work provides a promising strategy for tuning the surface acidity of ZSM-5 with Zr for ODHP applications.

关键词： flame synthesis Zr modified ZSM-5 catalyst ODHP surface acidity lattice oxygen

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Synthesis of covalent organic framework materials and their application in the field of sensing

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Nano Research 2024年第1期17卷 162-195页

作者： Weiyu Zhang Shiwei Liu Qihua Sun Ning tian Zhaofeng wu Xinjiang Key Laboratory of Solid-State Physics and Devices Urumqi 830046China School of Physics Science and Technology Xinjiang UniversityUrumqi 830046China

Covalent organic frameworks(COFs)are an emerging type of porous crystalline polymers formed by combining strong covalent bonds with organic building *** to their large surface area,high intrinsic pore space,good crystallization properties,high stability,and designability of the resultant units,COFs are widely studied and used in the fields of gas adsorption,drug transport,energy storage,photoelectric catalysis,electrochemistry,and *** recent years,the rapid development of the Internet of Things and people’s yearning for a better life have put forward higher and more requirements for sensors,which are the core components of the Internet of ***,this paper reviews the recent progress of COFs in synthesis methods and sensing applications,especially in the last five *** paper first introduces structure,properties,and synthesis methods of COFs and discusses advantages and disadvantages of different synthesis ***,the research progress of COFs in different sensing fields,such as metal ion sensors,gas sensors,biomedical sensors,humidity sensors,and pH sensors,is introduced *** and prospects are also presented in order to provide a reference for researchers concerned with COFs and sensors.

关键词： covalent organic framework materials structural design and synthesis sensing application gas sensors

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Visible Light-Induced Collapse of Molecular Microcrystals into Droplets by E-to-Z Photoisomerization and Melting Phase Transition

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CCS Chemistry 2024年第4期6卷 1071-1084页

作者： tian-Yi Xu Min Cui Chengxi Zhao Shang-wu Zhou tian-Le Zhang Hui-Yao Lin Fei Tong da-Hui Qu Key Laboratory for Advanced Materials and Feringa Nobel Prize Scientist Joint Research Center School of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai 200237

Harnessing photoresponsive behavior in organic crystals,such as shape and morphology deformation,on multiple scales is intriguing with respect to precise spatiotemporal operation,because dynamic deformations are promising in fabricating future intelligent ***,we synthesized a new photoresponsive molecular crystal composed of dimethyl(E)-2-(3-(naphthalen-1-yl)allylidene)malonate((E)-DNAM)that undergoes E-to-Z photoisomerization accompanied by photoinduced crystal-to-liquid melting phase transition when exposed to visible *** of expanding in bulk polycrystals,single-crystal(E)-DNAM rectangular microplates in an aqueous solution rapidly collapsed into liquid droplets,showing a remarkable drastic reduction in surface area of more than 97%after light *** deduce that the unique microscopic morphology of microplates with high aspect ratios of length-tothickness reaching up to 1000 is mainly responsible for the photoinduced melting leading to drastic *** addition,the cohesive forces of liquid photoproduct facilitate the overall deformations and *** have shown a facile way to achieve the remarkable collapse of molecular crystals into droplets by photochemical reaction and phase transition.

关键词： molecular crystals crystal-to-liquid transition extreme deformations photochemistry crystal engineering flexible crystals

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Low-permittivity LiLn(PO_(3))_(4)(Ln=La,Sm,Eu)dielectric ceramics for microwave/millimeter-wave communication

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Journal of Advanced Ceramics 2024年第5期13卷 602-620页

作者： Huanrong tian Xiaohan Zhang Zidong Zhang Yao Liu Haitao wu Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education) Shandong UniversityJinan 250061China School of Materials Science and Engineering Shandong UniversityJinan 250061China School of Environmental and Material Engineering Yantai UniversityYantai 264005China

The development of dielectric materials with low permittivity and low loss is a great challenge in wireless *** this study,LiLn(PO_(3))_(4)(Ln=La,Sm,Eu)ceramic systems were successfully prepared using the traditional solid-state method.X-ray diffraction analysis indicated that the LiLn(PO_(3))_(4)ceramics crystallized in a monoclinic structure when sintered at 850–940℃.The characteristic peak shifted to higher angles with variations in the Ln element,which was ascribed to a reduction in the cell *** analysis by structure refinement revealed that the reduction in the cell volume resulted from the decrease in chemical bond lengths and the compression of[LiO_(4)]and[PO_(4)]***,the LiLn(PO_(3))_(4)ceramic system displayed exceptional performance at low sintering temperatures(910–925℃),including a high quality factor(Q·f)of 41,607–75,968 GHz,low temperature coefficient of resonant frequency(τ_(f))ranging from−19.64 to−47.49 ppm/℃,low permittivity(ε_(r))between 5.04 and 5.26,and low density(3.04–3.26 g/cm^(3)).The application of Phillips–van Vechten–Levine(P–V–L)theory revealed that the increased Q·f value of the LiLn(PO_(3))_(4)systems can be attributed to the enhanced packing fraction,bond covalency,and lattice energy,and the stability of τ_(f) was associated with the increase in the bond ***,a prototype microstrip patch antenna using LiEu(PO_(3))_(4) ceramics was *** measurement results demonstrated excellent antenna performance with a bandwidth of 360 MHz and a peak gain of 5.11 dB at a central frequency of 5.08 ***,low-εr LiLn(PO_(3))_(4)ceramic systems are promising candidates for microwave/millimeter-wave communication.

关键词： low permittivity LiLn(PO_(3))_(4) microwave dielectric properties Phillips-van Vechten-Levine(P-V-L)theory microstrip patch antenna

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daIS: a method for identifying spatial domains based on density clustering of spatial omics data

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Journal of Genetics and Genomics 2024年第8期51卷 884-887页

作者： Qichao Yu Ru tian Xin Jin Liang wu College of Life Sciences University of Chinese Academy of SciencesBeijing 100049China BGI Research ShenzhenGuangdong 518083China BGI ResearchChongqing 401329China BGI Research ShenzhenGuangdong 518083China BGI Research Chongqing 401329China

In multicellular organisms,the spatial arrangement of cells profoundly influences the biological functions of tissues,underscoring the importance of identifying spatial domains in *** advancements in spatial omics,particularly spatial transcriptomics(ST)(Bressan et al.,2023),have enhanced our understanding of tissue spatial organization(Zhang et al.,2022;tian et al.,2023).

关键词： arrangement identifying domains

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Image Steganography by Pixel-Value Differencing Using General Quantization Ranges

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Computer Modeling in Engineering & Sciences 2024年第10期141卷 353-383页

作者： da-Chun wu Zong-Nan Shih Department of Computer and Communication Engineering National Kaohsiung University of Science and TechnologyKaohsiung824005Taiwan

A new steganographic method by pixel-value differencing(PVD)using general quantization ranges of pixel pairs’difference values is *** objective of this method is to provide a data embedding technique with a range table with range widths not limited to powers of 2,extending PVD-based methods to enhance their flexibility and data-embedding rates without changing their capabilities to resist security ***,the conventional PVD technique partitions a grayscale image into 1×2 non-overlapping *** entire range[0,255]of all possible absolute values of the pixel pairs’grayscale differences in the blocks is divided into multiple quantization *** width of each quantization range is a power of two to facilitate the direct embedding of the bit information with high embedding *** using power-of-two range widths,the embedding rates can drop using conventional embedding *** contrast,the proposed method uses general quantization range widths,and a multiple-based number conversion mechanism is employed skillfully to implement the use of nonpower-of-two range widths,with each pixel pair being employed to embed a digit in the multiple-based *** the message bits are converted into a big multiple-based number whose digits can be embedded into the pixel pairs with a higher embedding *** experimental results showed the feasibility of the proposed method and its resistance to security *** addition,implementation examples are provided,where the proposed method adopts non-power-of-two range widths and employsmultiple-based number conversion to expand the data-hiding and steganalysis-resisting capabilities of other PVD methods.

关键词： Steganography pixel-value differencing multiple-based number conversion general quantization range

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