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Recent progress and strategies of cathodes toward polysulfides shuttle restriction for lithium-sulfur batteries

Rare Metals 2024年第9期43卷 4132-4161页

作者： Xing-You Rao shuang-fei xiang Jian Zhou Zhen Zhang xiang-Yu Xu Yuan-Yuan Xu Xin-Chi Zhou Zheng-Dao Pan Su-Chong Tan Shi-Xing Dong Zhou-Lu Wang Yu-Tong Wu Yun-Lei Zhou xiang Liu Yi Zhang Shan Jiang School of Energy Sciences and Engineering Nanjing Tech University School of Materials Science and Engineering and Institute of Smart Fiber Materials Zhejiang Sci-Tech University JiangSu Sailboat Petrochemical Co. Ltd Hangzhou Institute of Technology Xidian University

Lithium-sulfur batteries(LSBs) have already developed into one of the most promising new-generation high-energy density electrochemical energy storage systems with outstanding features including high-energy density, low cost, and environmental friendliness. However, the development and commercialization path of LSBs still presents significant limitations and challenges, particularly the notorious shuttle effect triggered by soluble longchain lithium polysulfides(LiPSs), which inevitably leads to low utilization of cathode active sulfur and high battery capacity degradation, short cycle life, etc. Substantial research efforts have been conducted to develop various sulfur host materials capable of effectively restricting the shuttle effect. This review firstly introduces the fundamental electrochemical aspects of LSBs, followed by a comprehensive analysis of the mechanism underlying the shuttle effect in Li–S batteries and its profound influence on various battery components as well as the overall battery performance. Subsequently, recent advances and strategies are systematically reviewed, including physical confinement, chemisorption, and catalytic conversion of sulfur hosts for restricting LiPSs shuttle effects. The interplay mechanisms of sulfur hosts and LiPSs are discussed in detail and the structural advantages of different host materials are highlighted. Furthermore, key insights for the rational design of advanced host materials for LSBs are provided, and the upcoming challenges and the prospects for sulfur host materials in lithium-sulfur batteries are also explored.

关键词： Host Lithium-sulfur batteries Polysulfides Shuttle effect

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Reduction of unactivated alkyl chlorides enabled by light-induced single electron transfer

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Science China Chemistry 2024年第2期67卷 471-481页

作者： Lei Dai Zhao-fei Zhang xiang-Yu Chen School of Chemical Sciences University of the Chinese Academy of SciencesBeijing100049China Institute of Chemistry Chinese Academy of SciencesBeijing100190China Binzhou Institute of Technology Weiqiao-UCAS Science and Technology ParkBinzhou256606China

Alkyl chlorides are abundant and easily accessible starting ***,due to the high reduction potentials associated with unactivated alkyl chlorides,achieving their single electron reduction remains a persistent *** challenge has spurred the exploration of efficient activation methods to overcome this *** recent years,photocatalysis has emerged as a mild and potent tool for the single electron reduction of unactivated alkyl chlorides,opening up new possibilities in this *** the rapid advancements in this area,a comprehensive review that provides a conceptual understanding of this emerging field,with a specific focus on reaction design and catalytic mechanisms,would be timely and highly ***,we present an overview of various synthetic techniques for photoinduced single electron reduction of unactivated alkyl ***,we also discuss the limitations of the present methods and future directions that lie ahead in this field.

关键词： photocatalysis unactivated alkyl chlorides single electron transfer radical reactions

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Practical cloud storage auditing using serverless computing

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Science China(Information Sciences) 2024年第3期67卷 33-47页

作者： fei CHEN Jianquan CAI Tao xiang Xiaofeng LIAO College of Computer Science and Software Engineering Shenzhen University College of Computer Science Chongqing University

Cloud storage auditing research is dedicated to solving the data integrity problem of outsourced storage on the cloud. In recent years, researchers have proposed various cloud storage auditing schemes using different techniques. While these studies are elegant in theory, they assume an ideal cloud storage model;that is, they assume that the cloud provides the storage and compute interfaces as required by the proposed schemes. However, this does not hold for mainstream cloud storage systems because these systems only provide read and write interfaces but not the compute interface. To bridge this gap, this work proposes a serverless computing-based cloud storage auditing system for existing mainstream cloud object storage. The proposed system leverages existing cloud storage auditing schemes as a basic building block and makes two adaptations. One is that we use the read interface of cloud object storage to support block data requests in a traditional cloud storage auditing scheme. Another is that we employ the serverless computing paradigm to support block data computation as traditionally required. Leveraging the characteristics of serverless computing, the proposed system realizes economical, pay-as-you-go cloud storage auditing. The proposed system also supports mainstream cloud storage upper layer applications(e.g., file preview) by not modifying the data formats when embedding authentication tags for later auditing. We prototyped and open-sourced the proposed system to a mainstream cloud service, i.e., Tencent Cloud. Experimental results show that the proposed system is efficient and promising for practical use. For 40 GB of data, auditing takes approximately 98 s using serverless computation. The economic cost is 120.48 CNY per year, of which serverless computing only accounts for 46%. In contrast, no existing studies reported cloud storage auditing results for real-world cloud services.

关键词： cloud storage auditing serverless computing object storage usability

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Temperature prediction model in multiphase flow considering phase transition in the drilling operations

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Petroleum Science 2024年第3期21卷 1969-1979页

作者： Yang Zhang Yong-An Li xiang-Wei Kong Hao Liu Teng-fei Sun College of Mechanical and Electrical Engineering Beijing University of Chemical TechnologyBeijing 100027China School of Petroleum Engineering Yangtze UniversityWuhan430000HubeiChina

The study considers gas compression properties,gas slippage,back pressure(BP),phase transition(PT),well depth,and differences in gas-liquid physical properties.A new temperature model for multiphase flow is proposed by considering phase transition in the drilling *** mathematical model of multiphase flow is solved using the finite difference method with annulus mesh division for grid nodes,and a module for multiphase flow calculation and analysis is *** results indicate that the temperature varies along the annulus with the variation of gas influx at the bottom of the *** the process of controlled pressure drilling,as gas slips along the annulus to the wellhead,its volume continuously expands,leading to an increase in the gas content within the annulus,and consequently,an increase in the pressure drop caused by gas *** temperature increases with the increase in BP and decreases in gas influx rate and wellbore *** gas influx,the thermal conductivity coefficient for the gas-drilling mud two phases is significantly weakened,resulting in a considerable change in temperature along the *** the context of MPD,the method of slightly changing the temperature along the annulus by controlling the back pressure is feasible.

关键词： Managed pressure drilling Phase transition Temperature Gas-drilling mud two phase

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Effect of rare earth on primary carbides in H13 die steel and their addition method:a review

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Journal of Iron and Steel Research International 2024年第3期31卷 531-551页

作者： Jing-feng Wang Lin-zhu Wang Chao-yi Chen xiang Wang fei Zhao School of Materials and Metallurgy Guizhou UniversityGuiyang 550025GuizhouChina Zhengzhou Railway Vocational and Technical College Zhengzhou 450000HenanChina Guizhou Provincial University Key Laboratory of High Performance Battery Materials Guizhou UniversityGuiyang 550025GuizhouChina Shougang Guiyang Special Steel Co. Guiyang 550005GuizhouChina

Larger-sized primary carbides lead to stress concentration during the application of H13 hot-work die steel,resulting in microcracks and fatigue *** earth was usually added to modify the carbides and *** existing literature is reviewed on the effect of rare earth on primary carbides in H13 steel.A comprehensive review on the effect of rare earth on the characteristics of primary carbides,i.e.,number,size,morphology,and thermal stability in H13 steel,was *** precipitation mechanism and nucleation of primary carbides with rare earth were *** position and form of rare earth in steel and their effects on alloying elements segregation were *** addition techniques of rare earth in H13 steel were compared,and the prospects for other uncommon rare earth and emerging technology were *** on the current references,it can be known that adding rare earth facilitated refined and dispersed primary *** size of primary carbides would be reduced,and their morphology would be improved because the rare earth inclusions formed in H13 steel can act as nucleation cores forγ-Fe orδ-Fe,refining the dendritic ***,the number of primary carbides at grain boundaries would be significantly ***,rare earth had little impact on thermal *** nucleation of primary carbides tended to be inhibited due to the modification of inclusions by rare earth which were likely to be nucleation cores for primary *** earth had been reported to affect the mechanism and process of primary carbide ***,the addition of rare earth can inhibit the segregation of alloying elements and carbon diffusion by ***,laboratory experiments and theoretical calcu-lations need to be conducted to study the states and evolution of rare earth steels.

关键词： Rare earth H13 die steel Primary carbide Nucleation Dendritic structure

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Could the EU carbon border adjustment mechanism promote climate mitigation?An economy-wide analysis

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Advances in Climate Change Research 2024年第3期15卷 557-571页

作者： Kun ZHANG Yun-fei YAO xiang-Yan QIAN Yu-fei ZHANG Qiao-Mei LIANG Yi-Ming WEI College of Economics and Management Beijing University of TechnologyBeijing 100124China Center for Energy and Environmental Policy Research Beijing Institute of TechnologyBeijing 100081China School of Management and Economics Beijing Institute of TechnologyBeijing 100081China Beijing Key Laboratory of Energy Economics and Environmental Management Beijing 100081China Sinopec Research Institute of Petroleum Engineering SinopecBeijing 100101China College of Economics and Management Nanjing Agricultural UniversityNanjing 210095China

Due to concerns about carbon leakage and sectoral competitiveness,the European Union(EU)proposed implementing the carbon border adjustment mechanism(CBAM).The effectiveness and potential negative consequences of CBAM have aroused extensive *** the perspective of the economy-wide analysis,this study uses a global computable general equilibrium model to explore the rationality of CBAM from the aspects of socioeconomic impact and the effects of promoting climate ***,the potential alternative mechanism of CBAM is *** results show that CBAM can reduce the EU's gross domestic product(GDP)loss;however,the GDP loss in all other regions ***,CBAM raises household welfare losses in most regions,including the ***,although CBAM can reduce the marginal abatement cost in eight regions,it comes at the cost of greater economic ***,the economic and household welfare cost of raising emissions reduction targets in regions like the USA and Japan is substantially higher than the impact of passively accepting the CBAM;therefore,CBAM's ability to drive ambitious emission reduction initiatives may be ***,for the potential alternative mechanism,from the perspective of reducing economic cost and household welfare losses,the EU could implement domestic tax cuts in the short-term and promote global unified carbon pricing in the long-term.

关键词： Border adjustment mechanism Computable general equilibrium model Carbon price Climate policy Global carbon pricing

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Intelligent responsive self-assembled micro-nanocapsules: Used to delay gel gelation time

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Petroleum Science 2024年第4期21卷 2433-2443页

作者： Chuan-Hong Kang Ji-xiang Guo Dong-Tao fei Wyclif Kiyingi Unconventional Petroleum Research Institute China University of Petroleum

In the application of polymer gels to profile control and water shutoff,the gelation time will directly determine whether the gel can "go further" in the formation,but the most of the methods for delaying gel gelation time are complicated or have low *** is an urgent need for an effective method for delaying gel gelation time with intelligent *** by the slow-release effect of drug capsules,this paper uses the self-assembly effect of gas-phase hydrophobic SiO2in aqueous solution as a capsule to prepare an intelligent responsive self-assembled *** capsule slowly releases the cross-linking agent under the stimulation of external conditions such as temperature and pH value,thus delaying gel gelation *** the pH value is 2 and the concentration of gas-phase hydrophobic SiO2particles is 10%,the gelation time of the capsule gel system at 30,60,90,and 120℃ is12.5,13.2,15.2,and 21.1 times longer than that of the gel system without containing capsule,*** with other methods,the yield stress of the gel without containing capsules was 78 Pa,and the yield stress after the addition of capsules was 322 *** intelligent responsive self-assembled micronanocapsules prepared by gas-phase hydrophobic silica nanoparticles can not only delay the gel gelation time,but also increase the gel *** slow release of cross-linking agent from capsule provides an effective method for prolongating the gelation time of polymer gels.

关键词： Profile control and water shutoff Polymer gel Delayed gelation time Intelligent response Self-assembled Micro-nanocapsules

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Spark plasma sintering of tungsten-based WTaVCr refractory high entropy alloys for nuclear fusion applications

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International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 146-154页

作者： Yongchul Yoo xiang Zhang fei Wang Xin Chen Xing-Zhong Li Michael Nastasi Bai Cui Department of Mechanical&Materials Engineering University of Nebraska-LincolnLincolnNE 68588USA Nebraska Center for Materials and Nanoscience University of Nebraska-LincolnLincolnNE 68588USA Department of Nuclear Engineering Texas A&M UniversityCollege StationTX 77843USA

W-based WTaVCr refractory high entropy alloys (RHEA) may be novel and promising candidate materials for plasma facing components in the first wall and diverter in fusion reactors. This alloy has been developed by a powder metallurgy process combining mechanical alloying and spark plasma sintering (SPS). The SPSed samples contained two phases, in which the matrix is RHEA with a body-centered cubic structure, while the oxide phase was most likely Ta2VO6through a combined analysis of X-ray diffraction (XRD),energy-dispersive spectroscopy (EDS), and selected area electron diffraction (SAED). The higher oxygen affinity of Ta and V may explain the preferential formation of their oxide phases based on thermodynamic calculations. Electron backscatter diffraction (EBSD) revealed an average grain size of 6.2μm. WTaVCr RHEA showed a peak compressive strength of 2997 MPa at room temperature and much higher micro-and nano-hardness than W and other W-based RHEAs in the literature. Their high Rockwell hardness can be retained to at least 1000°C.

关键词： refractory high entropy alloy plasma-facing material fusion reactor spark plasma sintering

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Recent progress in hair follicle stem cell markers and their regulatory roles

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World Journal of Stem Cells 2024年第2期16卷 126-136页

作者： Yi-Zhan Xing Hai-Ying Guo fei xiang Yu-Hong Li Department of Cell Biology Army Medical UniversityChongqing 400038China Institute of Burn Research Southwest HospitalArmy Medical UniversityChongqing 400038China

Hair follicle stem cells(HFSCs)in the bulge are a multipotent adult stem cell *** can periodically give rise to new HFs and even regenerate the epidermis and sebaceous glands during wound *** increasing number of biomarkers have been used to isolate,label,and trace HFSCs in recent *** more detailed data from single-cell transcriptomics technology,we mainly focus on the important HFSC molecular markers and their regulatory roles in this review.

关键词： Hair follicle stem cells Bulge Secondary hair germ Marker Single-cell RNA-sequencing

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Extraction of fractures in shale CT images using improved U-Net

Energy Geoscience

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Energy Geoscience 2024年第2期5卷 240-248页

作者： xiang Wu fei Wang Xiaoqiu Zhang Bohua Han Qianru Liu Yonghao Zhang College of Geology Engineering and Geomatics Chang'an UniversityXi'anShaanxi710054China Qinghai Oilfield Exploration and Development Research Institute DunhuangGansu736202China China Petroleum Logging Co.Ltd. Xi'anShaanxi710077China

Accurate extraction of pores and fractures is a prerequisite for constructing digital rocks for physical property simulation and microstructural response ***,fractures in CT images are similar in grayscale to the rock matrix,and traditional algorithms have difficulty to achieve accurate segmentation *** this study,a dataset containing multiscale fracture information was constructed,and a U-Net semantic segmentation model with a scSE attention mechanism was used to classify shale CT images at the pixel level and compare the results with traditional *** results showed that the CLAHE algorithm effectively removed noise and enhanced the fracture information in the dark parts,which is beneficial for further fracture *** Canny edge detection algorithm had significant false positives and failed to recognize the internal information of the *** Otsu algorithm only extracted fractures with a significant difference from the background and was not sensitive enough for fine *** MEF algorithm enhanced the edge information of the fractures and was also sensitive to fine fractures,but it overestimated the aperture of the *** U-Net was able to identify almost all fractures with good continuity,with an MIou and Recall of 0.80 and 0.82,*** the image resolution increases,more fine fracture information can be extracted.

关键词： CT slices Fracture segmentation Shale U-Net Deep learning

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