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Hydrogen generation from NaBH_(4) for portable proton exchange membrane fuel cell

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Materials Reports(Energy) 2024年第1期4卷 69-78页

作者： Bingxue sun Xingguo Li jie Zheng Beijing National Laboratory for Molecular Sciences(BNLMS) College of Chemistry and Molecular EngineeringPeking UniversityBeijing100871PR China

Sodium borohydride(NaBH_(4)) is considered as the most potential hydrogen storage material for portable proton exchange membrane fuel cells(PEMFC)because of its high theoretical hydrogen ***,the slow and poor kinetic stability of hydrogen generation from NaBH_(4) hydrolysis limits its *** are two main factors influencing the kinetics stability of hydrogen generation from NaBH_(4).One factor is that the alkaline byproducts(NaBO_(2)) of the hydrolysis reaction can increase the pH of the solution,thus inhibiting the reaction *** mainly happens in the NaBH_(4) solution hydrolysis *** factor is that the monotonous increase in reaction temperature leads to uncontrollable and unpredictable hydrolysis rates in the solid NaBH_(4) hydrolysis *** is due to the excess heat generated from this exothermic reaction in the initial reaction of NaBH_(4) *** this perspective,we summarize the latest research progress in hydrogen generation from NaBH_(4) and emphasize the design principles of catalysts for hydrogen generation from NaBH_(4) solution and solid state NaBH_(4).The importance of carbon as catalyst support material for NaBH_(4) hydrolysis is also highlighted.

关键词： NaBH_(4)hydrolysis Hydrogen generation Catalyst Kinetics Carbon support materials

Experimental and simulation research on hollow AZ31 magnesium alloy three-channel joint by hot extrusion forming with sand mandrel

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Journal of Magnesium and Alloys 2024年第1期12卷 98-109页

作者： Shi Shengnan Wang Hongyu Teng Fei Jiang Lei sun Juncai sun jie Zhang Shunhu Transportation Engineering College Dalian Maritime UniversityDalianLiaoning 106026China State Key Laboratory of Rolling and Automation Northeastern UniversityShenyangLiaoning 110819China Shagang School of Iron and Steel Soochow UniversitySuzhouJiangsu 215021China

Magnesium alloy is one of the lightest metal structural *** weight is further reduced through the hollow ***,the hollow structure is easily damaged during *** order to maintain the hollow structure and to transfer the stresses during the high temperature deformation,the sand mandrel is *** this paper,the hollow AZ31 magnesium alloy three-channel joint is studied by hot extrusion *** as one of solid granule medium is used to fill the hollow magnesium *** extrusion temperatures are 230℃ and 300℃,*** process parameters(die angle,temperature,bottom thickness,sidewall thickness,edge-to-middle ratio in bottom,bottom shape)of the hollow magnesium alloy are analyzed based on the results of experiments and the finite element *** results are shown that the formability of the hollow magnesium alloy will be much better when the ratio of sidewall thickness to the bottom thickness is 1:*** when edge-to-middle ratio in bottom is about 1:1.5,a better forming product can be *** best bottom shape in these experiments will be convex based on the forming *** grain will be refined obviously after the *** the microstructures will be shown as *** these lines will be well agreement with the mold in the corner.

关键词： AZ31 magnesium alloy Three-channel joint Sand Experiments and the finite element Die angle

Special Issue:Dynamic Polymer Networks

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Chinese Journal of Polymer Science 2024年第10期42卷 1401-1402页

作者： Jun-Qi sun zhi-Bo Li Tao Xie 不详

The ease of processing and light weight have made polymeric materials uniquely suited for numerous general ***,realization of their switchable chain configuration/mobility and molecular design versatility has pushed p... 详细信息

关键词： uniquely realization polymeric

Microstructures and mechanical properties of laser-directed energy deposited CrCoNi medium-entropy alloy

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Rare Metals 2024年第7期43卷 3286-3300页

作者： Wen-jie Zhao Chang-Yu Liu Peng-Cheng Che zhi-Liang Ning Hong-Bo Fan Jian-Fei sun Yong-Jiang Huang Alfonso H.W.Ngan National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of TechnologyHarbin 150001China Space Environment Simulation Research Infrastructure Harbin Institute of TechnologyHarbin 150001China Department of Mechanical Engineering The University of Hong KongHong Kong 999077China

The distinctive intrinsic heat treatment(IHT)originating from cyclic reheating in the laser-directed energy deposition(LDED) has attracted growing attention in recent *** this investigation,simulations and experimental characterizations were performed to examine the impact of IHT on the micros true ture and mechanical properties of LDED-fabricated CrCoNi medium-entropy alloy(MEA).The results show that the intensity of the IHT is proportional to the utilized laser energy density(LED).As the LED increased,significant dynamic recrystallization and grain refinement occurred within the alloy due to the enhanced intensity of ***,the high LED leads to severe hot cracking within the as-built MEA,resulting in inferior *** decreasing LED,the hot cracking was effectively ***,low LED weakened the intensity of IHT and consequently inhibited kinetic conditions of dynamic recrystallization,resulting in a heterogeneous grain structure characterized by multi-scale-sized *** structure provides significant hetero-deformation-induced hardening during plastic deformation,enabling the alloy to have a sustainable work-hardening *** expect that this work will have implications in taking full advantage of the unique IHT of the LDED process to fabricate ME As with excellent metallurgical quality and mechanical performance.

关键词： Intrinsic heat treatment Laser-directed energy deposition CrCoNi MEA Dynamic recrystallization Heterogeneous grain structure

Chaotic CS Encryption:An Efficient Image Encryption Algorithm Based on Chebyshev Chaotic System and Compressive Sensing

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Computers, Materials & Continua 2024年第5期79卷 2625-2646页

作者： Mingliang sun jie Yuan Xiaoyong Li Dongxiao Liu Key Laboratory of Trustworthy Distributed Computing and Service(BUPT) Ministry of EducationBeijing University of Posts and TelecommunicationsBeijing100876China

Images are the most important carrier of human information. Moreover, how to safely transmit digital imagesthrough public channels has become an urgent problem. In this paper, we propose a novel image encryptionalgorithm, called chaotic compressive sensing (CS) encryption (CCSE), which can not only improve the efficiencyof image transmission but also introduce the high security of the chaotic system. Specifically, the proposed CCSEcan fully leverage the advantages of the Chebyshev chaotic system and CS, enabling it to withstand various attacks,such as differential attacks, and exhibit robustness. First, we use a sparse trans-form to sparse the plaintext imageand then use theArnold transformto perturb the image pixels. After that,we elaborate aChebyshev Toeplitz chaoticsensing matrix for CCSE. By using this Toeplitz matrix, the perturbed image is compressed and sampled to reducethe transmission bandwidth and the amount of data. Finally, a bilateral diffusion operator and a chaotic encryptionoperator are used to perturb and expand the image pixels to change the pixel position and value of the compressedimage, and ultimately obtain an encrypted image. Experimental results show that our method can be resistant tovarious attacks, such as the statistical attack and noise attack, and can outperform its current competitors.

关键词： Image encryption chaotic system compressive sensing arnold transform

MicroRNAs:A novel signature in the metastasis of esophageal squamous cell carcinoma

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World Journal of Gastroenterology 2024年第11期30卷 1497-1523页

作者： Qi-Ying Wei Feng Jin Zhong-Yu Wang Bing-jie Li Wen-Bo Cao zhi-Yan sun Sai-Jun Mo Department of Pathophysiology School of Basic Medical SciencesZhengzhou UniversityZhengzhou 450001Henan ProvinceChina Department of Perioperative Medicine The First Affiliated Hospital of Zhengzhou UniversityZhengzhou 450052Henan ProvinceChina Division of Special Service Department of Basic OncologySchool of Basic MedicineZhengzhou UniversityZhengzhou 450001Henan ProvinceChina Department of Basic Science of Oncology School of Basic Medical SciencesZhengzhou UniversityZhengzhou 450001Henan ProvinceChina

Esophageal squamous cell carcinoma(ESCC)is a malignant epithelial tumor,characterized by squamous cell differentiation,it is the sixth leading cause of cancer-related deaths *** increased mortality rate of ESCC patients is predominantly due to the advanced stage of the disease when discovered,coupled with higher risk of metastasis,which is an exceedingly malignant charac-teristic of cancer,frequently leading to a high mortality ***,there is currently no specific and effective marker to predict and treat metastasis in ***(miRNAs)are a class of small non-coding RNA molecules,approximately 22 nucleotides in *** are vital in modulating gene expression and serve pivotal regulatory roles in the occurrence,progression,and prognosis of ***,we have examined the literature to highlight the intimate correlations between miRNAs and ESCC metastasis,and show that ESCC metastasis is predominantly regulated or regulated by genetic and epigenetic *** review proposes a potential role for miRNAs as diagnostic and therapeutic biomarkers for metastasis in ESCC metastasis,with the ultimate aim of reducing the mortality rate among patients with ESCC.

关键词： MicroRNAs Esophageal squamous cell carcinoma Metastasis Signaling pathway Epigenetics mechanism

Gelation mechanisms of gel polymer electrolytes for zinc-based batteries

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Chinese Chemical Letters 2024年第5期35卷 97-116页

作者： Mengjun sun zhi Wang Jvhui Jiang Xiaobing Wang Chuang Yu Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals Key Laboratory of Green Chemical Media and ReactionsMinistry of EducationSchool of Chemistry and Chemical EngineeringHenan Normal UniversityXinxiang 453007China Key Laboratory for Yellow River and Huaihe River Water Environment and Pollution Control Ministry of EducationHenan Key Laboratory for Environmental Pollution ControlSchool of EnvironmentHenan Normal UniversityXinxiang 453007China State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074China

Zinc-based batteries(ZBs)have been deemed as a potential substitute for lithium-ion batteries due to its unique advantages of abundant resources,low cost and acceptable energy *** great progress in designing electrode materials has been made,the development of high-performance ZBs still remain challenges,such as the dendrite growth of zinc anode,hydrogen evolution reaction,limited electrochemical stability window,water evaporation and liquid *** polymer electrolytes(GPEs),including hydrous GPEs with low content of active water and anhydrous GPEs without the presence of water,are proposed to avoid these ***,employing GPEs is conductive to fabricate flexible devices owing to the good mechanical *** date,most of researches focus on discovering new GPEs and exploring its application on flexible or wearable *** reviews also have outlined the polymer matrixes and advances of GPEs in various battery *** this,herein,we seek to summarize the gelation mechanisms of GPEs,involving physical gel of polymer,chemical crosslinking of polymer and chemical polymerization of ***,the preparation methods are also *** addition,not only the features and central conundrum of GPEs are analyzed but also the corresponding strategies are discussed,contributing to design GPEs with ideal properties for high-performance ZBs.

关键词： Gelation mechanisms Gel polymer electrolytes Zinc-based batteries Gelation methods

Electrolyte Design for Low‑Temperature Li‑Metal Batteries:Challenges and Prospects

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Nano-Micro Letters 2024年第2期16卷 365-382页

作者： Siyu sun Kehan Wang Zhanglian Hong Mingjia zhi Kai Zhang Jijian Xu Department of Chemistry City University of Hong KongHong Kong 999077People’s Republic of China State Key Laboratory of Silicon Materials School of Materials Science and EngineeringZhejiang UniversityHangzhou 310027People’s Republic of China State Key Laboratory of Advanced Chemical Power Sources Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education)Haihe Laboratory of Sustainable Chemical TransformationsCollaborative Innovation Center of Chemical Science and Engineering(Tianjin)College of ChemistryNankai UniversityTianjin 300071People’s Republic of China Department of Chemical and Biomolecular Engineering University of Maryland College ParkCollege ParkMD 20742USA

Electrolyte design holds the greatest opportunity for the development of batteries that are capable of sub-zero temperature *** get the most energy storage out of the battery at low temperatures,improvements in electrolyte chemistry need to be coupled with optimized electrode materials and tailored electrolyte/electrode ***,this review critically outlines electrolytes’limiting factors,including reduced ionic conductivity,large de-solvation energy,sluggish charge transfer,and slow Li-ion transportation across the electrolyte/electrode interphases,which affect the low-temperature performance of Li-metal *** theoretical derivations that explain the explicit influence of temperature on battery performance are presented to deepen *** improvement strategies from the aspects of electrolyte design and electrolyte/electrode interphase engineering are summarized and rigorously *** on future research are proposed to guide the ongoing exploration for better low-temperature Li-metal batteries.

关键词： Solid electrolyte interphase Li metal Low temperature Electrolyte design Batteries

Micromechanical modeling of longitudinal tensile behavior and failure mechanism of unidirectional carbon fiber/aluminum composites involving fiber strength dispersion

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Chinese Journal of Aeronautics 2024年第9期37卷 312-327页

作者： Qipeng LIU Wengang JIANG Yuehua GAO Zhenjun WANG Shanshan SHI zhi sun Jiangxi Key Laboratory of Forming and Joining Technology for Aerospace Components Nanchang Hangkong UniversityNanchang 330063China School of Locomotive and Rolling Stock Engineering Dalian Jiaotong UniversityDalian 116028China State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentDalian University of TechnologyDalian 116024China

This paper examines the longitudinal tensile behavior and failure mechanism of a new unidirectional carbon fiber reinforced aluminum composite through experiments and simulations.A Weibull distribution model was established to describe the fiber strength dispersion based on single-fiber tensile tests for carbon fibers extracted from the *** constitutive models for the matrix and interface were established based on the uniaxial tensile and single-fiber push-out tests,***,a 3D micromechanical numerical model,innovatively considering the fiber strength dispersion by use of the weakest link and Weibull distribution theories,was estab-lished to simulate the progressive failure behavior of the composite under longitudinal *** to the dispersion of fiber strength,the weakest link of the fiber first fractures,and stress concentra-tion occurs in the surrounding fibers,interfaces,and *** maximum stress concentration fac-tor for neighboring fibers varies nonlinearly with the distance from the fractured *** isolated and clustered fractured fibers are present during the progressive failure process of the *** expansion of fractured fiber clusters intensifies stress concentration and material degradation which in turn enlarges the fractured fiber clusters,and their mutual action leads to the final collapse of the composite.

关键词： Fiber reinforced metals Finite element method 3D micromechanical model Fiber strength dispersion Longitudinal tension Progressive failure