检索结果-南通市图书馆

2.5 μm-Thick Ultrastrong Asymmetric Separator for Stable Lithium Metal Batteries

在线全文

学校读者我要写书评

暂无评论

ENERGY & ENVIRONMENTAL maTERIALS 2024年第6期7卷 106-117页

作者： Xie, Donghao Wang, Zekun ma, Xin feng, Yuchen Tang, Xiaomin Gu, Qiao Deng, Yonghong Gao, Ping Hong Kong Univ Sci & Technol Adv Mat Thrust Interdisciplinary Off Clear Water Bay Hong Kong 999077 Peoples R China Hong Kong Univ Sci & Technol Guangzhou Adv Mat Thrust Funct Hub Guangzhou 511453 Peoples R China Hong Kong Univ Sci & Technol Dept Chem & Biol Engn Clear Water Bay Hong Kong 999077 Peoples R China Southern Univ Sci & Technol Dept Mat Sci & Engn Shenzhen 518055 Peoples R China

Lithium metal batteries (LMBs) are considered the ideal choice for high volumetric energy density lithium-ion batteries, but uncontrolled lithium deposition poses a significant challenge to the stability of such devices. In this paper, we introduce a 2.5 mu m-thick asymmetric and ultrastrong separator, which can induce tissue-like lithium deposits. The asymmetric separator, denoted by utPE@Cu2O, was prepared by selective synthesis of Cu2O nanoparticles on one of the outer surfaces of a nanofibrous (diameter similar to 10 nm) ultrastrong ultrahigh molecular weight polyethylene (UHMWPE) membrane. Microscopic analysis shows that the lithium deposits have tissue-like morphology, resulting in the symmetric lithium cells assembled using utPE@Cu2O with symmetric Cu2O coating exhibiting stable performance for over 2000 h of cycling. This work demonstrates the feasibility of a facile approach ultrathin separators for the deployment of lithium metal batteries, providing a pathway towards enhanced battery performance and safety.

关键词： in situ SEI lithium deposition regulation separator ultrastrong ultrathin DEAD LITHIUM GROWTH MECHANISMS ELECTRODEPOSITION DISSOLUTION MICROSCOPY DEPENDENCE MORPHOLOGY BEHAVIOR CELL

Stable carbon isotope composition and intrinsic water use efficiency in plants along an altitudinal gradient on the eastern slope of Yulong Snow Mountain, China

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Ecological Processes 2024年第2期13卷 218-230页

作者： feng Jiang Tao Pu Zi-Jing Xue Yan-Wei ma Xiao-Yi Shi Fu-Xi Shi College of Geography and Environmental Sciences Zhejiang Normal University Yulong Snow Mountain Glacier and Environment Observation and Research Station/State Key Laboratory of Cryospheric Sciences Northwest Institute of Eco-Environment and ResourcesChinese Academy of Sciences Key Laboratory of National Forestry and Grassland Administration on Forest Ecosystem Protection and Restoration of Poyang Lake Watershed College of Forestry Jiangxi Agricultural University

Background Stable carbon isotope composition(δ13Cp) can be used to estimate the changes in intrinsic water use efficiency（iWUE） in plants,which helps us to better understand plants' response strategies to climate *** study focused on the variations in δ13Cpand iWUE for the different life-form plants（i.e.,herbs,shrubs,and trees）along an altitudinal gradient（3300,3600,3900,4100,4300,and 4500 m） on the eastern slope of Yulong Snow Mountain,southeastern margin of the Qinghai-Tibet *** response mechanisms of δ13Cpand iWUE for different life-form plants to altitude were thoroughly analyzed in this mountain *** The δ13Cpvalues of plants on the eastern slopes of Yulong Snow Mountain ranged from-30.4‰to-26.55‰,with a mean of-28.02‰,indicating a dominance of *** δ13Cpand iWUE values varied among different life-form plants in the order of herbs> shrubs> trees,particularly in 3600,3900,and 4300 ***δ13Cpand iWUE values for herbs and shrubs increased with altitude and were mainly controlled by air *** two parameters for trees exhibited a trend of initial decrease followed by an increase with *** 3900 m,the δ13Cpand iWUE values decreased with altitude,influenced by soil ***,above 3900 m,the two parameters increased with altitude,mainly regulated by air *** addition,iWUE was positively correlated with leaf P content but negatively correlated with leaf N:P ratio,especially for herbs and trees,suggesting that P plays a key role in modulating iWUE in this *** The diffe rentiated responses of water availability for different life-form plants to a higher altitudinal gradient are regulated by air temperature,soil moisture,and leaf P content in the Yulong Snow *** results provide valuable insights into understanding the wate r-carbon relationships in high-altitude ecosystems.

关键词： Stable carbon isotope Water use efficiency Altitude Life form Yulong Snow Mountain

Efficient and rapid capture of uranium(Ⅵ) in wastewater via multiamine modified β-cyclodextrin porous polymer

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2024年第4期68卷 144-155页

作者： Xing Zhong Yubin Tan Siyuan Wu Caixia Hu Kai Guo Yongchuan Wu Neng Yu Mingyang ma ying Dai School of Chemistry and materials Science East China University of TechnologyNanchang 330013China

It is quite important to ensure the safety and sustainable development of nuclear energy for the treatment of radioactive wastewater. To treat radioactive wastewater efficiently and rapidly, two multi-amine β-cyclodextrin polymers(diethylenetriamine β-cyclodextrin polymer(DETA-TFCDP) and triethylenetetramine β-cyclodextrin polymer(TETA-TFCDP)) were prepared and applied to capture uranium. Results exhibited that DETA-TFCDP and TETA-TFCDP displayed the advantages of high adsorption amounts(612.2and 628.2 mg·g-1, respectively) and rapid adsorption rates, which can reach(88 ± 1)% of their equilibrium adsorption amounts in 10 min. Moreover, the adsorbent processes of DETA-TFCDP and TETATFCDP on uranium(Ⅵ) followed the Langmuir model and pseudo-second-order model, stating they were mainly chemisorption and self-endothermic. Besides, TETA-TFCDP also showed excellent selectivity in the presence of seven competing cations and could be effectively reused five times via Na2CO3as the desorption reagent. Meanwhile, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy illustrated that the enriched multi-amine groups and oxygen-containing functional groups on the surface of TETA-TFCDP were the main active sites for capturing uranium(Ⅵ). Hence, multi-amine β-cyclodextrin polymers are a highly efficient, rapid, and promising adsorbent for capturing uranium(Ⅵ)from radioactive wastewater.

关键词： Adsorption Waste water Pollution Uranium(VI) b-Cyclodextrin

Gradient sparsification for efficient wireless federated learning with differential privacy

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2024年第4期67卷 272-288页

作者： Kang WEI Jun LI Chuan ma Ming DING feng SHU Haitao ZHAO Wen CHEN Hongbo ZHU School of Electronic and Optical Engineering Nanjing University of Science and Technology Zhejiang Lab Key Laboratory of Computer Network and Information Integration(Southeast University) Ministry of Education Data61 Commonwealth Scientific and Industrial Research Organisation School of Information and Communication Engineering Hainan University School of Communications and Information Engineering Nanjing University of Posts and Telecommunications School of Electronic Information and Electrical Engineering Shanghai Jiao Tong University

Federated learning(FL) enables distributed clients to collaboratively train a machine learning model without sharing raw data with each other. However, it suffers from the leakage of private information from uploading models. In addition, as the model size grows, the training latency increases due to the limited transmission bandwidth and model performance degradation while using differential privacy(DP)protection. In this paper, we propose a gradient sparsification empowered FL framework with DP over wireless channels, to improve training efficiency without sacrificing convergence performance. Specifically, we first design a random sparsification algorithm to retain a fraction of the gradient elements in each client’s local model, thereby mitigating the performance degradation induced by DP and reducing the number of transmission parameters over wireless channels. Then, we analyze the convergence bound of the proposed algorithm, by modeling a non-convex FL problem. Next, we formulate a time-sequential stochastic optimization problem for minimizing the developed convergence bound, under the constraints of transmit power, the average transmitting delay, as well as the client’s DP requirement. Utilizing the Lyapunov drift-plus-penalty framework, we develop an analytical solution to the optimization problem. Extensive experiments have been implemented on three real-life datasets to demonstrate the effectiveness of our proposed algorithm. We show that our proposed algorithms can fully exploit the interworking between communication and computation to outperform the baselines, i.e., random scheduling, round robin, and delay-minimization algorithms.

关键词： federated learning differential privacy gradient sparsification Lyapunov drift convergence analysis

Insight into the capacity degradation and structural evolution of single-crystal Ni-rich cathodes

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第8期95卷 68-76,I0003页

作者： Xiaodong Zhang Jiao Lin Ersha Fan Qingrong Huang Su ma Renjie Chen feng Wu Li Li Beijing Key Laboratory of Environmental Science and Engineering School of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081China Advanced Technology Research Institute Beijing Institute of TechnologyJinan 250300ShandongChina Collaborative Innovation Center of Electric Vehicles in Beijing Beijing 100081China

Single-crystal Ni-rich cathodes are a promising candidate for high-energy lithium-ion batteries due to their higher structural and cycling stability than polycrystalline ***,the phase evolution and capacity degradation of these single-crystal cathodes during continuous lithation/delithation cycling remains *** the mapping relationship between the macroscopic electrochemical properties and the material physicochemical properties is ***,we investigate the correlation between the physical-chemical characteristics,phase transition,and capacity decay using capacity differential curve feature identification and in-situ X-ray spectroscopic *** systematically clarify the dominant mechanism of phase evolution in aging *** high cut-off voltages can mitigate the slow kinetic and electrochemical properties of single-crystal *** also find that second-order differential capacity discharge characteristic curves can be used to identify the crystal structure disorder of Ni-rich *** findings constitute a step forward in elucidating the correlation between the electrochemical extrinsic properties and the physicochemical intrinsic properties and provide new perspectives for failure analysis of layered electrode materials.

关键词： Single-crystal cathodes Capacity decay Phase transition Differential capacity analysis

MOF‐derived 1D/3D N‐doped porous carbon for spatially confined electrochemical CO2 reduction to adjustable syngas

在线全文

学校读者我要写书评

暂无评论

Carbon Energy 2024年第8期6卷 1-13页

作者： Wei Zhang Hui Li Daming feng Chenglin Wu Chenghua Sun Baohua Jia Xue Liu Tianyi ma Key Laboratory for Green Synthesis and Preparative Chemistry of Advanced materials Institute of Clean Energy ChemistryCollege of ChemistryLiaoning UniversityShenyangLiaoningChina School of Science RMIT UniversityMelbourneVictoriaAustralia School of Pharmaceutical and Chemical Engineering Taizhou UniversityTaizhouZhejiangChina Department of Chemistry and Biotechnology Swinburne University of TechnologyHawthornVictoriaAustralia

Electrochemical reduction of CO_(2)to syngas(CO and H_(2))offers an efficient way to mitigate carbon emissions and store intermittent renewable energy in ***,the hierarchical one‐dimensional/three‐dimensional nitrogen‐doped porous carbon(1D/3D NPC)is prepared by carbonizing the composite of Zn‐MOF‐74 crystals in situ grown on a commercial melamine sponge(MS),for electrochemical CO_(2)reduction reaction(CO_(2)RR).The 1D/3D NPC exhibits a high CO/H_(2)ratio(5.06)and CO yield(31 mmol g^(−1)h^(−1))at−0.55 V,which are 13.7 times and 21.4 times those of 1D porous carbon(derived from Zn‐MOF‐74)and N‐doped carbon(carbonized by MS),*** is attributed to the unique spatial environment of 1D/3D NPC,which increases the adsorption capacity of CO_(2)and promotes electron transfer from the 3D N‐doped carbon framework to 1D carbon,improving the reaction kinetics of CO_(2)*** results and charge density difference plots indicate that the active site of CO_(2)RR is the positively charged carbon atom adjacent to graphitic N on 1D carbon and the active site of HER is the pyridinic N on 1D *** presence of pyridinic N and pyrrolic N reduces the number of electron transfer,decreasing the reaction kinetics and the activity of CO_(2)*** CO/H_(2)ratio is related to the distribution of N species and the specific surface area,which are determined by the degree of spatial confinement *** CO/H_(2)ratios can be regulated by adjusting the carbonization temperature to adjust the degree of spatial confinement *** the low cost of feedstock and easy strategy,1D/3D NPC catalysts have great potential for industrial application.

关键词： electrochemical CO_(2)reduction reaction melamine sponge metal‐organic frameworks porous carbon syngas

Human radiological safety assessment for petawatt laser-driven ion acceleration experiments in CLAPA-T

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

matter and Radiation at Extremes 2024年第4期9卷 8-15页

作者： Xiaopeng Zhang Jiarui Zhao Shengxuan Xu Xun Chen ying Gao Shiyou Chen Kun Zhu Xueqing Yan Wenjun ma State Key Laboratory of Nuclear Physics and Technology and Key Laboratory of HEDP of the Ministry of EducationCAPTPeking UniversityBeijing 100871China Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsCASBeijing 100049China Beijing Laser Acceleration Innovation Center HuairouBeijing 101400China Institute of Guangdong Laser Plasma Technology BaiyunGuangzhou 510540China

The newly built Compact Laser Plasma Accelerator-Therapy facility at Peking University will deliver 60 J/1 Hz laser pulses with 30 fs *** by this petawatt laser facility,proton beams with energy up to 200 MeV are expected to be generated for tumor *** high-repetition operation,both prompt radiation and residual radiation may cause safety ***,human radiological safety assessment before commissioning is *** this paper,we simulate both prompt and residual radiation using the Geant4 and FLUKA Monte Carlo codes with reasonable proton and as-produced electron beam *** find that the prompt radiation can be shielded well by the concrete wall of the experimental hall,but the risk from residual radiation is nonnegligible and necessitates adequate radiation *** the basis of the simulation results,we discuss the constraints imposed by radiation safety considerations on the annual working time,and we propose radiation cooling strategies for different shooting modes.

关键词： laser prompt acceleration

Evolution of the porous structure for phosphoric acid etching carbon as cathodes in Li–O_(2) batteries:Pyrolysis temperature-induced characteristics changes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Carbon Energy 2024年第1期6卷 172-181页

作者： Feiyang Yang ying Yao Yunkai Xu Cong Wang Meiling Wang Jingjie Ren Cunzhong Zhang feng Wu Jun Lu Beijing Key Laboratory of Environmental Science and Engineering School of Materials Science and EngineeringBeijing Institute of TechnologyBeijingChina Beijing Institute of Technology Chongqing Innovation Center ChongqingChina College of Chemical and Biological Engineering Zhejiang UniversityHangzhouChina

Although biomass-derived carbon(biochar)has been widely used in the energy field,the relation between the carbonization condition and the physical/chemical property of the product remains ***,we revealed the carbonization condition's effect on the morphology,surface property,and electrochemical performance of the obtained *** open slit pore structure with shower-puff-like nanoparticles can be obtained by finely tuning the carbonization temperature,and its unique pore structure and surface properties enable the Li–O_(2) battery with cycling longevity(221 cycles with 99.8%Coulombic efficiency at 0.2 ma cm^(−2) and controlled discharge–charge depths of 500 mah g^(−1))and high capacity(16,334 mah g^(−1) at 0.02 ma cm^(−2)).This work provides a greater understanding of the mechanism of the biochar carbonization procedure under various pyrolysis conditions,paving the way for future study of energy storage devices.

关键词： biomass Li-O_(2) battery oxygen catalysts porous carbon temperature parameters

Microstructures and mechanical properties of a commercial Mg-Al-Zn-Mn alloy with various hot-extrusion processes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2024年第3期43卷 1329-1336页

作者： He ma Fan-Zhi Meng Qiang Yang Ze-feng Xie Yuan-Ding Huang Xin Qiu State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun130022China School of materials Science and Engineering Changchun University of Science and TechnologyChangchun130022China magIC-magnesium Innovation Center Helmholtz-Zentrum Geesthacht21502GeesthachtGermany Engineering Research Center of Optoelectronic Functional materials Ministry of EducationChangchun University of Science and TechnologyChangchun130022China

Mg-Al-Zn-Mn(AZ)system alloys have become widely used due to their good castability,excellent formability and outstanding corrosion resistance[1-6].However,their strength is still much lower than that of traditional Mg... 详细信息

关键词： alloys alloy corrosion