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How to estimate isotope fractionations of a Rayleigh-like but diffusion-limited disequilibrium process?

Acta Geochimica 2023年第1期42卷 24-37页

作者： Zi xuan guan Yun Liu School of Earth and Space Science Peking UniversityBeijing 100871China State Key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China International Center for Planetary Science College of Earth ScienceChengdu University of TechnologyChengdu 610059China CAS Center for Excellence in Comparative Planetology Hefei 230026China

The Rayleigh distillation isotope fractionation(RDIF) model is one of the most popular methods used in isotope geochemistry. Numerous isotope signals observed in geologic processes have been interpreted with this model. The RDIF model provides a simple mathematic solution for the reservoir-limited equilibrium isotope fractionation effect. Due to the reservoir effect, tremendously large isotope fractionations will always be produced if the reservoir is close to being depleted. However, in real situations, many prerequisites assumed in the RDIF model are often difficult to meet. For instance, it requires the relocated materials, which are removed step by step from one reservoir to another with different isotope compositions(i.e., with isotope fractionation), to be isotopically equilibrated with materials in the first reservoir simultaneously. This ‘‘quick equilibrium requirement’’ is indeed hard to meet if the first reservoir is sufficiently large or the removal step is fast. The whole first reservoir will often fail to re-attain equilibrium in time before the next removal *** problem led the RDIF model to fail to interpret isotope signals of many real situations. Here a diffusion-coupled and Rayleigh-like(i.e., reservoir-effect included) separation process is chosen to investigate this problem. We find that the final isotope fractionations are controlled by both the diffusion process and the reservoir effects via the disequilibrium separation process. Due to its complexity, we choose to use a numerical simulation method to solve this problem by developing specific computing codes for the working *** to our simulation results, the classical RDIF model only governs isotope fractionations correctly at the final stages of separation when the reservoir scale(or thickness of the system) is reduced to the order of magnitude of the quotient of the diffusivity and the separation rate. The RDIF model fails in other situations and the isotope fractionations

关键词： Isotope fractionation Reservoir isotope effect Rayleigh-like distillation process Diffusional isotope effect Numerical modeling Disequilibrium process

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乡村振兴背景下农村会计工作的不足与对策

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商业观察 2024年第2期10卷 28-31,35页

作者：牛帅景管璇重庆理工大学重庆401320 江西工业工程职业技术学校江西萍乡337000

随着经济的发展,农村地区的经济趋向复杂化和多元化,然而农村会计却越来越难以适应日益复杂的经济环境,亟需做出改变。在乡村振兴战略提出之后,农村地区受到了越来越多来自社会各界的关注。文章重点从主体地位、会计制度、监督管理、人... 详细信息

随着经济的发展,农村地区的经济趋向复杂化和多元化,然而农村会计却越来越难以适应日益复杂的经济环境,亟需做出改变。在乡村振兴战略提出之后,农村地区受到了越来越多来自社会各界的关注。文章重点从主体地位、会计制度、监督管理、人才培养及信息化建设5个方面分析农村会计的现存问题,进而提出针对性的建议,以期加快农村地区的会计建设,使其更好地提供与经济水平相适应的会计服务,为实现乡村振兴战略提供动力。

关键词：乡村振兴农村会计会计建设

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小额信贷机构愿意继续帮扶脱贫户吗？——基于政银关联和委托代理的调查与实证分析

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安徽工业大学学报(自然科学版) 2024年第1期41卷 98-108页

作者：刘艳华陈佳管璇安徽工业大学商学院

从政银关联和委托代理关系视角分析小额信贷机构(MFI)对脱贫户帮扶意愿形成的理论逻辑，基于小额信贷机构帮扶意愿的现状调查与分析，利用Ologit排序模型对影响MFI帮扶意愿的主要因素进行实证分析。结果表明：以所有权和管理控制权为基... 详细信息

从政银关联和委托代理关系视角分析小额信贷机构(MFI)对脱贫户帮扶意愿形成的理论逻辑，基于小额信贷机构帮扶意愿的现状调查与分析，利用Ologit排序模型对影响MFI帮扶意愿的主要因素进行实证分析。结果表明：以所有权和管理控制权为基础的政银关系和信贷帮扶机制中的委托代理关系，是影响MFI对脱贫户帮扶意愿的主要因素；MFI的帮扶意愿程度总体较低，但农村金融机构的帮扶意愿高于商业银行，且传统农村金融机构高于新型农村金融机构；政银合作和信贷帮扶激励会显著推动MFI对脱贫户的帮扶，脱贫人口小额信贷风险会显著降低MFI的帮扶意愿，而帮扶效果和扶贫小额信贷的可持续性对推动帮扶具有积极作用。基于此，应明确MFI的社会责任，进一步优化小额信贷政策的激励机制，针对不同类型的MFI实施差异化的激励和约束政策，提高脱贫户的生产创收能力和信用意识。

关键词：小额信贷机构脱贫人口小额信贷帮扶意愿

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Role of Chinese Herbal Medicines in Regulation of Energy Metabolism in Treating Cardiovascular Diseases

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Chinese Journal of Integrative Medicine 2019年第4期25卷 307-315页

作者： LI Jie guan xuan-ke LIU Ru-xiu Department of Cardiology Guang'anmen HospitalChinese Academy of Chinese Medical SciencesBeijing(100053)China

Recently,studying myocardial energy metabolism pathways or improving myocardial metabolism through drugs is another effective strategy for treating ischemic heart *** active components of Chinese herbal medicines(CHMs) have been found to modulate energy metabolism in myocardial cells,cerebral vascular cells,endothelial cells and tumour *** paper reviews the advances in studies on the active components of CHMs that modulating energy metabolism in treating cardiovascular diseases over the past ?ve years.

关键词： biologically active ingredient Chinese herbal medicine cardiovascular disease ischemic heart disease heart failure

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Thermodynamics and Kinetics of Bacterial Cellulose Adsorbing Persistent Pollutant from Aqueous Solutions

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Chemical Research in Chinese Universities 2015年第2期31卷 298-302页

作者： LU Min LU xuan XU Xiaohui guan Xiaohui School of Chemical Engineering Northeast Dianli University Jilin 132012 P. R. China

The adsorption capability of bacterial cellulose（BC） for anionic dye acid fuchsine was studied. Meanwhile, the processes of the adsorption were investignted and fitted by adsorption isotherm models, adsorption thermodynamics and adsorption kinetics models, respectively. The changes of BC before and after adsorbing acid fuchsine were investigated via scanning electron microscopy（SEM） and Fourier transform infrared spectroscopy（FTIR） to further explain the adsorption mechanism. The results show that acid fuchsine could be effectively adsorbed by BC. The adsorption process was fitted well by Langmuir equation and the pseudo-second order kinetics, indicating that the adsorption process was monolayer molecule adsorption with the main action of chemical adsorption. The adsorption process was spontaneous and endothermic. Glucuronic acid groups and hydroxyl groups were responsible for the adsorption of acid fuchsine on BC.

关键词： Adsorption thermodynamics Adsorption kinetics Persistent pollutant Bacterial cellulose

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SNL fibroblast feeder layers support derivation and maintenance of human induced pluripotent stem cells

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Journal of Genetics and Genomics 2010年第4期37卷 241-248页

作者： Chuanying Pan Amy Hicks xuan guan Hong Chen Colin E. Bishop College of Animal Science and Technology Shaanxi Key Laboratory of Molecular BiologyJbr Agriculture Northwest A & F University Yangling 712100 China Wake Forest University Institute for Regenerative Medicine Wake Forest University Winston-Salem NC 2 7101 USA

Induced pluripotent stem （iPS） cells can be derived from human somatic cells by cellular reprograrnming. This technology provides a potential source of non-controversial therapeutic ceils for tissue repair, drug discovery, and opportunities for studying the molecular basis of human disease. Normally, mouse embryonic fibroblasts （MEFs） are used as feeder layers in the initial derivation of iPS lines. The pur- pose of this study was to determine whether SNL fibrohlasts can be used to support the growth of human iPS cells reprogrammed from somatic cells using lentiviral expressed reprogramming factors. In our study, iPS cells expressed common pluripotency markers, dis- played human embryonic stem cells （hESCs） morphology and unmethylated promoters of NANOG and OCT4. These data demonstrate that SNL feeder cells can support the derivation and maintenance of human iPS cells.

关键词： induced pluripotent stem cells derivation maintenance SNL feeder cells

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Effective Activation of Melamine for Synchronous Synthesis of Catalytically Active Nanosheets and Fluorescence-Responsive Quantum Dots

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Transactions of Tianjin University 2024年第3期30卷 284-296页

作者： Jie xuan Guijian guan Ming-Yong Han Institute of Molecular Plus Tianjin UniversityTianjin 300072China

Because of the low reactivity of cyclic nitrides,liquid-phase synthesis of carbon nitride introduces challenges despite its favorable potential for energy-efficient preparation and superior *** this study,we demonstrate a strong interaction between citric acid and melamine through experimental observation and theoretical simulation,which eff ectively activates melamine-condensation activity and produces carbon-rich carbon nitride nanosheets(CCN NSs)during hydrothermal *** a large specific surface area and increased light absorption,these CCN NSs demonstrate significantly enhanced photocatalytic activity in CO_(2) reduction,increasing the CO production rate by approximately tenfold compared with hexagonal melamine(h-Me).Moreover,the product selectivity of CCN NSs reaches up to 93.5%to generate CO from CO_(2).Furthermore,the annealed CCN NSs exhibit a CO conversion rate of up to 95.30μmol/(g h),which indicates an 18-fold increase compared with traditional carbon *** the CCN NS synthesis,nitrogen-doped carbon quantum dots(NDC QDs)are simultaneously produced and remain suspended in the supernatant after *** QDs disperse well in water and exhibit excellent luminescent properties(QY=67.2%),allowing their application in the design of selective and sensitive sensors to detect pollutants such as pesticide 2,4-dichlorophenol with a detection limit of as low as 0.04μmol/***,the simultaneous synthesis of CCN NSs and NDC QDs provides a cost-eff ective and highly efficient process,yielding products with superior capabilities for catalytic conversion of CO_(2) and pollutant detection,respectively.

关键词： Carbon nitride Hydrothermal reaction Photocatalysis Carbon dioxide Quantum dots

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荧光假单胞菌噬菌体对大西洋鲑贮藏过程中品质变化规律研究

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食品安全质量检测学报 2024年第10期15卷 279-287页

作者：刘显君林洪玄冠华王静雪中国海洋大学食品科学与工程学院青岛266404

目的探究大西洋鲑在4℃贮藏过程中,外源添加荧光假单胞菌及其噬菌体影响大西洋鲑品质变化规律。方法采用色差值、菌落总数(total viable count,TVC)、挥发性盐基氮(total volatile basic nitrogen,TVB-N)、质构、硫代巴比妥酸(thiobarbi... 详细信息

目的探究大西洋鲑在4℃贮藏过程中,外源添加荧光假单胞菌及其噬菌体影响大西洋鲑品质变化规律。方法采用色差值、菌落总数(total viable count,TVC)、挥发性盐基氮(total volatile basic nitrogen,TVB-N)、质构、硫代巴比妥酸(thiobarbituric acid,TBA)、pH、剪切力、持水性等指标对冷藏温度(4℃)条件下大西洋鲑的品质变化进行综合评价。结果4℃贮藏期间,初期微生物生长迅速且菌相变化明显,噬菌体vB_PF_Y1-MI的加入使得鱼肉中TVC下降大约0.07 lg(CFU/g);大西洋鲑TVB-N含量整体变化趋势明显呈指数型增长,pH均呈现先下降后上升的变化趋势;添加荧光假单胞菌组的大西洋鲑TBA值和失水率增加程度较明显,经噬菌体处理后有所降低。结论噬菌体v B_PF_Y1-MI的加入,能够降低大西洋鲑鱼肉脂质氧化速率,可以延缓其腐败变质,从而延长大西洋鲑保质期。

关键词：荧光假单胞菌噬菌体大西洋鲑食品保鲜剂水产品

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Cultural Topics Discussed at National Congress Session

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China & The World Cultural Exchange 2015年第4期81卷 9-10页

作者： guan xuan

During the NPC and CPPCC annual sessions in about culture, such as the ＂going global＂ strategy, along ＂One Belt and One Road＂. 2015, representatives carried out pragmatic discussions and China＇s cooperation and e... 详细信息

关键词：中国文化对外文化交流文化产业

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FUSE: a federated learning and U-shape split learning-based electricity theft detection framework

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Science China(Information Sciences) 2024年第4期67卷 339-340页

作者： xuan LI Naiyu WANG Liehuang ZHU Shuai YUAN Zhitao guan School of Control and Computer Engineering North China Electric Power University School of Cyberspace Science and Technology Beijing Institute of Technology Department of Finance Operationsand Information Systems(FOIS)Brock University

In recent years, the data-driven electricity theft detection methods integrated with edge cloud computing [1, 2] have not only demonstrated superior detection accuracy but also improved efficiency, making them viable alternatives to indoor inspections. Energy service providers(ESPs) typically manage regions by dividing them into various transformer districts(TDs). The detection of electricity theft in a particular region is performed by the associated TD,

关键词： Sensitive data

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