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Advancements in the modification of magnesium-based hydrogen storage materials

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Progress in Natural Science:Materials International 2024年第3期34卷 540-554页

作者： Lin Yang wen zeng Yanqiong Li College of Materials Science and Engineering Chongqing University School of Electronic Information & Electrical Engineering Chongqing University of Arts and Sciences

Magnesium-based hydrogen storage materials represent a hydrogen storage technology with broad application prospects. As the global energy crisis and environmental pollution issues become increasingly severe, hydrogen,as a clean and efficient energy source, has garnered growing attention. Magnesium-based hydrogen storage,serving as a crucial means for storing and transporting hydrogen, is gaining prominence due to its abundant resources, low cost, low density, and high hydrogen storage density. However, challenges in terms of absorption/desorption rates, temperature, activation energy, and enthalpy during hydrogen application impede its development. To address these challenges, this paper systematically reviews current research on magnesium-based hydrogen storage materials, encompasses their types, characteristics, and hydrogen absorption mechanisms.Furthermore, it delves into the impacts of nanoscale dimensions, alloying, doping, and catalysis on the performance of magnesium-based materials. The aim is to provide valuable insights for research in related fields.

关键词： For hydrogen storage Magnesium-based materials Research on modifying

Anomalous spin Josephson effect in spin superconductors

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Chinese Physics B 2024年第3期33卷 126-131页

作者：曾文沈瑞 School of Physics and Electronic Engineering Jiangsu UniversityZhenjiang 212013China Jiangsu Engineering Research Center on Quantum Perception and Intelligent Detection of Agricultural InformationZhenjiang 212013China National Laboratory of Solid State Microstructures and School of Physics Nanjing UniversityNanjing 210093China Collaborative Innovation Center of Advanced Microstructures Nanjing UniversityNanjing 210093China

The spin superconductor state is the spin-polarized triplet exciton condensate,which can be viewed as a counterpart of the charge superconductor state.As an analogy of the charge Josephson effect,the spin Josephson effect can be generated in the spin superconductor/normal metal/spin superconductor junctions.Here we study the spin supercurrent in the Josephson junctions consisting of two spin superconductors with noncollinear spin polarizations.For the Josephson junctions with out-of-plane spin polarizations,the possibleπ-state spin supercurrent appears due to the Fermi momentum-splitting Andreev-like reflections at the normal metal/spin superconductor interfaces.For the Josephson junctions with in-plane spin polarizations,the anomalous spin supercurrent appears and is driven by the misorientation angle of the in-plane polarizations.The symmetry analysis shows that the appearance of the anomalous spin Josephson current is possible when the combined symmetry of the spin rotation and the time reversal is broken.

关键词： tunneling junction spin supercurrent 0-πtransition anomalous spin Josephson effect

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Giant panda(Ailuropoda melanoleuca)neonates use broadband calls to communicate with their mothers

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Integrative Zoology 2024年第2期19卷 277-287页

作者： Lin ZHAO Jianbin CHENG wen zeng Bo YANG Guiquan ZHANG Desheng LI Hemin ZHANG Christina DBUESCHING Dingzhen LIU Ministry of Education Key Laboratory of Biodiversity Science and Ecological EngineeringCollege of Life SciencesBeijing Normal UniversityBeijingChina Key Laboratory of State Forestry and Grassland Administration on Conservation Biology of Rare Animals in The Giant Panda National Park China Conservation and Research Center for the Giant PandaDujiangyanSichuan611830China Department of Biology Irving K.Barber Faculty of ScienceUniversity of British ColumbiaOkanaganKelownaBritish ColumbiaCanada

Infant call structure should have evolved to elicit maximum maternal attention and investment.Neonates of giant pandas produce three types of vocalizations reported to be vitally important in the context of mother–infant communications.However,how cubs,0–15 days old,communicate with their mothers to elicit maternal care remains unknown.We analyzed 12 different call parameters of 3475 squawks,1355 squalls,and 491 croaks from 11 captive giant panda(Ailuropoda melanoleuca)neonates from age 0 to 15 days.In playback experiments,we also tested whether mothers could detect ultrasound.Our results show that neonates use broadband calls with ultrasonic frequencies up to 65 kHz to convey information about their physiological needs and to attract maternal care.In playback experiments,we tested if mothers reacted differently to broadband calls(BBC)than to artificially altered calls that included only frequencies20 kHz(USC).Playback confirmed that,although adult females responded significantly less often to USC,BBC than to or AUDC,they could detect USC,BBC and generally made appropriate behavioral responses,indicating a potential benefit for neonates to utilize ultrasonic and broadband frequencies.Our findings provide a new insight into mother–infant communication in giant pandas and will be helpful for reducing the mortality of cubs,younger than 1 month old,in captivity.

关键词： acoustic communication broadband calls maternal care neonates ultrasonic frequencies

Finding slid pairs in trivium with MiniSat

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Science China(Information Sciences) 2013年第9期56卷 249-256页

作者： zeng wen QI wenFeng Department of Applied Mathematics Zhengzhou Information Science and Technology Institute

A pair of distinct (key, IV) is said to be slidable if they can produce two identical keystreams up to a shift. In this paper, we investigate slid pairs in Trivium. We convert the resulting nonlinear sliding equations into a SAT instance and use MiniSat, a SAT solver, to solve it. We not only find more slid pairs than previous result on slid pair in Trivium but also provide a new method which can treat higher clock-shifts and is much less time-consuming.

关键词： eSTREAM MiniSat stream cipher SAT slid pairs trivium

金融健康背景下农户消费信贷的杠杆效应——基于农村固定观察点数据的分析

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消费经济 2024年第2期40卷 37-50页

作者：曾学文张斌中国农业银行中国农业银行博士后科研工作站对外经济贸易大学博士后流动站

壮大农村消费市场,既要发挥好消费信贷的加速器作用,同时也要兼顾好农户金融健康问题。本文使用农研中心农村固定观察点调查数据库,实证考察了金融健康背景下农户消费信贷的杠杆效应。研究发现,消费信贷激活农村消费存在“倒U型”特征,... 详细信息

壮大农村消费市场,既要发挥好消费信贷的加速器作用,同时也要兼顾好农户金融健康问题。本文使用农研中心农村固定观察点调查数据库,实证考察了金融健康背景下农户消费信贷的杠杆效应。研究发现,消费信贷激活农村消费存在“倒U型”特征,农户适度加杠杆有利于消费扩张,并驱动其由生存型消费为主向发展型和享受型消费升级,但杠杆率过高对消费增长将形成反向抑制;进一步就异质性影响看,不同农户群体、不同地域之间的特征表现存在一定的差异。就不同群体看,以农村公共服务、私营企业经营为主要收入来源的农户相比以农业经营、务工收入为主的农户,消费信贷激活消费支出的弹性更强,消费信贷拓展空间更大;就不同地域看,中、西部地区农村消费信贷发展相对滞后,激发农户消费的边际动能不足。本文为平衡好农户消费信贷和金融健康之间的逻辑关系提供了经验证据,为精准化提升农村消费金融服务,支持农户消费信贷可持续发展提供了理论遵循。

关键词：金融健康消费信贷农户消费扩容升级非线性影响

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Experimental study on combustion characteristics of Chinese RP-3 kerosene

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Chinese Journal of Aeronautics 2016年第2期29卷 375-385页

作者： Ma Hongan Xie Maozhao zeng wen Chen Baodong School of Energy and Power Engineering Dalian University of Technology Liaoning Key Laboratory of Advanced Test Technology for Aerospace Propulsion System Shenyang Aerospace University

In order to illustrate the combustion characteristics of RP-3 kerosene which is widely used in Chinese aero-engines, the combustion characteristics of RP-3 kerosene were experimentally inves- tigated in a constant volume combustion chamber. The experiments were performed at four different pressures of 0.1 MPa, 0.3 MPa, 0.5 MPa and 0.7 MPa, and three different temperatures of 390 K, 420 K and 450 K, and over the equivalence ratio range of 0.6-1.6. Furthermore, the laminar combus- tion speeds of a surrogate fuel for RP-3 kerosene were simulated under certain conditions. The results show that increasing the initial temperature or decreasing the initial pressure causes an increase in the laminar combustion speed of RP-3 kerosene. With the equivalence ratio increasing from 0.6 to 1.6, the laminar combustion speed increases initially and then decreases gradually. The highest laminar combustion speed is measured under fuel rich condition （the equivalence ratio is 1.2）. At the same time, the Markstein length shows the same changing trend as the laminar com- bustion speed with modification of the initial pressure. Increasing the initial pressure will increase the instability of the flame front, which is established by decreased Markstein length. However, different from the effects of the initial temperature and equivalence ratio on the laminar combustion speed, increasing the equivalence ratio will lead to a decrease in the Markstein length and the stability of the flame front, and the effect of the initial temperature on the Markstein length is unclear. Further- more, the simulated laminar combustion speeds of the surrogate fuel agree with the corresponding experimental datas of RP-3 kerosene within ~10% deviation under certain conditions.

关键词： Combustion mechanism Combustion stability Laminar combustion speed Markstein length RP-3 kerosene

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Data augmentation for bias correction in mapping PM_(2.5) based on satellite retrievals and ground observations

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Geoscience Frontiers 2024年第1期15卷 17-28页

作者： Tan Mi Die Tang Jianbo Fu wen zeng Michael L.Grieneisen Zihang Zhou Fengju Jia Fumo Yang Yu Zhan College of Carbon Neutrality Future Technology Sichuan UniversityChengduSichuan 610065China Department of Environmental Science and Engineering Sichuan UniversityChengduSichuan 610065China Institute for Disaster Management and Reconstruction Sichuan UniversityChengduSichuan 610200China Department of Land Airand Water ResourcesUniversity of CaliforniaDavisCA 95616United States Chengdu Academy of Environmental Sciences ChengduSichuan 610072China Sichuan Chengdu Ecological and Environment Monitoring Center ChengduSichuan 610011China

As most air quality monitoring sites are in urban areas worldwide,machine learning models may produce substantial estimation bias in rural areas when deriving spatiotemporal distributions of air pollutants.The bias stems from the issue of dataset shift,as the density distributions of predictor variables differ greatly between urban and rural areas.We propose a data-augmentation approach based on the multiple imputation by chained equations(MICE-DA)to remedy the dataset shift problem.Compared with the benchmark models,MICE-DA exhibits superior predictive performance in deriving the spatiotemporal distributions of hourly PM2.5 in the megacity(Chengdu)at the foot of the Tibetan Plateau,especially for correcting the estimation bias,with the mean bias decreasing from-3.4µg/m3 to-1.6µg/m3.As a complement to the holdout validation,the semi-variance results show that MICE-DA decently preserves the spatial autocorrelation pattern of PM2.5 over the study area.The essence of MICE-DA is strengthening the correlation between PM2.5 and aerosol optical depth(AOD)during the data augmentation.Consequently,the importance of AOD is largely enhanced for predicting PM2.5,and the summed relative importance value of the two satellite-retrieved AOD variables increases from 5.5%to 18.4%.This study resolved the puzzle that AOD exhibited relatively lower importance in local or regional studies.The results of this study can advance the utilization of satellite remote sensing in modeling air quality while drawing more attention to the common dataset shift problem in data-driven environmental research.

关键词： Aerosol optical depth Dataset shift Spatiotemporal Distribution Air quality monitoring Multiple imputation by chained equations

Association analysis of an anti-obesity mechanism and key ripened Pu-erh tea bioactive components by mimicking human general tea drinking

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Food Science and Human Wellness 2024年

作者： Junyu Liu Zhengyang Song Haihong Chen wen zeng Guirong Han Wei Li Bing Xu Yuan Lu Canyang Zhang Zhenglian Xue Bin Lü Chong Zhang Song Yang Yi Wang Xinhui Xing Institute of Biomedical Health Technology and Engineering Shenzhen Bay Laboratory MOE Key Laboratory for Industrial Biocatalysis Centre for Synthetic and Systems Biology Department of Chemical Engineering Tsinghua University Shenzhen International Graduate School Tsinghua University Shandong Province Key Laboratory of Applied Mycology Qingdao International Center on Microbes Utilizing Biogas School of Life Sciences Qingdao Agricultural University Anhui University of Technology Yunnan Shujian Tea Co. Ltd.

Pu-erh tea， a traditional Chinese beverage， performs an anti-obesity function， but the correlation between its components and efficacy remains unknown. Here， we screened two Pu-erh teas with significant anti-obesity efficacies from 11 teas. In vitro experiments revealed that lipid accumulation in L02 cells and lipid synthesis in 3T3-L1 cells were significantly better inhibited by Tea-B than Tea-A. Further in vivo experiments using model mice revealed that the differences in chemical components generated two pathways in the anti-obesity efficacy and mechanism of Pu-erh teas. Tea-A changes the histomorphology of brown adipose tissue (BAT) and increases the abundance of Coriobacteriaceae＿UCG＿002 and cyclic AMP in guts through high chemical contents of cyclopentasiloxane， decamethyl， tridecane and 1，2，3-trimethoxybenzene， eventually increasing BAT activation and fat browning gene expression; the high content of hexadecane and 1，2-dimethoxy-benzene in Tea-B reduces white adipose tissue (WAT) accumulation and the process of fatty liver， increases the abundance of Odoribacter and sphinganine 1-phosphate， inhibits the expression of lipid synthesis and transport genes. These mechanistic findings on the association of the representative bioactive components in Pu-erh teas with the anti-obesity phenotypes， gut microbes， gut metabolite structure and anti-obesity pathways， which were obtained for the first time， provide foundations for developing functional Pu-erh tea.

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基于频域解离特征的OCT指纹表征攻击检测

计算机学报 2024年第2期47卷 323-336页

作者：刘凤曾文锋张文天孔哲王磊沈琳琳深圳大学计算机与软件学院广东深圳518060 广东省智能信息处理重点实验室广东深圳518060 深圳市人工智能与机器人研究院广东深圳518060 中国科学院深圳先进技术研究院广东深圳518055

在自动指纹识别系统中,指纹防伪能力的发展至关重要.传统指纹一般由表面成像得到,而这种表面的纹理特征极容易被盗取.基于这种传统指纹的识别系统,检测指纹表征攻击的能力十分有限.因此,现有研究普遍针对具有防伪特征的指纹模态,如具有... 详细信息

在自动指纹识别系统中,指纹防伪能力的发展至关重要.传统指纹一般由表面成像得到,而这种表面的纹理特征极容易被盗取.基于这种传统指纹的识别系统,检测指纹表征攻击的能力十分有限.因此,现有研究普遍针对具有防伪特征的指纹模态,如具有汗腺特征的高精度指纹和具有指静脉特征的指纹开发表征攻击检测算法.在本篇工作中,为了进一步提高指纹系统的表征攻击检测能力,我们提出一种基于光学相干断层扫描技术(Optical Coherence Tomography,OCT)的频域指纹表征攻击检测方法.与以往方法不同,我们首先利用卷积神经网络和残差结构设计了一个频域特征解离模型,通过该模型可以分别解离出时域中叠加在原始OCT指纹图像上的信息(如区分性特征、无效特征和冗余特征).然后,我们让它学习不同的频域编码,并结合OCT指纹在时域中的重构编码形成相应的潜层编码.利用潜层编码,我们设计了一种用于区分表征攻击指纹和真实指纹的预测模型,用于表征攻击检测.在目前常用的OCT指纹数据集上的实验结果表明,我们的方法可以通过在频域中分离出一些叠加在时域中的无用干扰信息,从而有效地消除干扰.在实例方面,该方法的最小误差(Err.)为0.67%,与已有的基于时域的最优方法相比,最小误差降低了3.03%,性能提高了81.89%.

关键词：表征攻击检测光学相干断层扫描技术离散小波变换频域解离自动编码器

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