检索结果-南通市图书馆

基于Logistic回归Cobb-Douglas模型的人才资本贡献率研究

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

上海交通大学学报 2011年第1期45卷 110-114页

作者：林龙斌郁佳敏上海交通大学国际公共事务管理学院上海200240 上海金融学院保险研究所上海201209

以上海市闵行区为例,采用Logistic回归的Cobb-Douglas（C-D）生产函数模型计算上海市闵行区1992~2008年的人才资本贡献率,并分析了影响人才资本贡献率的因素.结果表明：从1992~2008年,上海市闵行区的人才资本贡献率为24.6%;尤其是从200... 详细信息

以上海市闵行区为例,采用Logistic回归的Cobb-Douglas（C-D）生产函数模型计算上海市闵行区1992~2008年的人才资本贡献率,并分析了影响人才资本贡献率的因素.结果表明：从1992~2008年,上海市闵行区的人才资本贡献率为24.6%;尤其是从2005年以来,其人力资本的投入大幅增长,与该时期闵行区生产总值的增长趋势相一致,表明人才资本对闵行区经济发展的促进效应日渐增强.同时指出,需要对C-D模型加以改进,并考虑产业适用性、基础统计数据的完整性以及非学历人力资本投入等因素对人才资本贡献率的影响.

关键词：人才资本贡献率 Cobb-Douglas生产函数闵行区

基于时变假设的修正负二项车险索赔频率精算模型

在线全文

学校读者我要写书评

暂无评论

系统管理学报 2010年第3期19卷 339-344页

作者：郁佳敏上海金融学院保险研究所上海201209

传统车险索赔频率模型都采用风险水平在保险期间保持不变的假设,采用风险水平时变假设,选择Weibull过程作为风险强度函数,引入传统的负二项索赔频率模型。新模型修改原有频域方法为时域参数方法进行参数估计,并使用极大似然估计结合贝... 详细信息

传统车险索赔频率模型都采用风险水平在保险期间保持不变的假设,采用风险水平时变假设,选择Weibull过程作为风险强度函数,引入传统的负二项索赔频率模型。新模型修改原有频域方法为时域参数方法进行参数估计,并使用极大似然估计结合贝叶斯估计的方法估计出Weibull过程的水平参数λ和形状参数β。在β=1时,新模型就等价于传统负二项模型;此外,新模型可为风险上升(β>1)和风险下降(β<1)的保单确定更准确的风险保费。

关键词：时变 Weibull过程索赔频率负二项模型车险

在线全文

学校读者我要写书评

暂无评论

我国各省保险业与经济发展的相关性实证研究

金融理论与实践 2011年第2期 94-98页

作者：郁佳敏上海金融学院保险研究所上海201209

本文采用典型关系分析方法对我国各省的保险业发展和经济增长相关关系问题进行了实证研究。研究结果表明,保险密度与当地的经济发展水平具有密切的正相关性;保险结构主要受经济增长方式的影响;保险业未来的发展依赖于经济转型和人力资... 详细信息

本文采用典型关系分析方法对我国各省的保险业发展和经济增长相关关系问题进行了实证研究。研究结果表明,保险密度与当地的经济发展水平具有密切的正相关性;保险结构主要受经济增长方式的影响;保险业未来的发展依赖于经济转型和人力资本的拉动。

关键词：保险业经济增长相关性典型相关分析

缺乏先验信息条件下的对数正态分布车险索赔额定价模型

在线全文

学校读者我要写书评

暂无评论

系统管理学报 2011年第6期20卷 762-764页

作者：郁佳敏上海金融学院保险研究所上海201209

假定车险索赔额服从对数正态损失分布,并且其结构方差和过程方差存在显著差异,通过分析全体车险保单组合的历史索赔损失数据,估计出结构方差和过程方差的先验参数,从而得到个体保单未来索赔额的最优估计模型;在此基础上,给出了一个既考... 详细信息

假定车险索赔额服从对数正态损失分布,并且其结构方差和过程方差存在显著差异,通过分析全体车险保单组合的历史索赔损失数据,估计出结构方差和过程方差的先验参数,从而得到个体保单未来索赔额的最优估计模型;在此基础上,给出了一个既考虑索赔频率又考虑索赔严重性的车险经验费率定价模型。

关键词：汽车保险索赔额对数正态分布定价

Ideal Bi‑Based Hybrid Anode Material for Ultrafast Charging of Sodium‑Ion Batteries at Extremely Low Temperatures

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2025年第3期17卷 152-167页

作者： Jie Bai jian Hui jia yu Wang Chun Cheng Yang Qing jiang Key Laboratory of Automobile Materials(Jilin University) Ministry of EducationSchool of Materials Science and EngineeringJilin UniversityChangchun 130022People’s Republic of China

Sodium-ion batteries have emerged as competitive substitutes for low-temperature applications due to severe capacity loss and safety concerns of lithium-ion batteries at−20°C or ***,the key capability of ultrafast charging at ultralow temperature for SIBs is rarely ***,a hybrid of Bi nanoparticles embedded in carbon nanorods is demonstrated as an ideal material to address this issue,which is synthesized via a high temperature shock *** a hybrid shows an unprecedented rate performance(237.9 mAh g^(−1)at 2 A g^(−1))at−60℃,outperforming all reported SIB anode *** with a Na_(3)V_(2)(PO_(4))_(3)cathode,the energy density of the full cell can reach to 181.9 Wh kg^(−1)at−40°*** on this work,a novel strategy of high-rate activation is proposed to enhance performances of Bi-based materials in cryogenic conditions by creating new active sites for interfacial reaction under large current.

关键词： Bi nanoparticles High temperature shock High-rate activation Ultrafast charging Low-temperature sodium-ion batteries

Porous Organic Cage‑Based Quasi‑Solid‑State Electrolyte with Cavity‑Induced Anion‑Trapping Effect for Long‑Life Lithium Metal Batteries

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano-Micro Letters 2025年第2期17卷 376-386页

作者： Wei-min Qin Zhongliang Li Wen‑Xia Su jia‑min Hu Hanqin Zou Zhixuan Wu Zhiqin Ruan yue‑Peng Cai Kang Li Qifeng Zheng School of Chemistry South China Normal UniversityGuangzhou 510006People’s Republic of China Key Laboratory of Functional Metal‑Organic Compounds of Hunan Province College of Chemistry and Material ScienceHengyang Normal UniversityHengyang 421008People’s Republic of China Guangzhou Key Laboratory of Energy Conversion and Energy Storage Materials Guangzhou 510006People’s Republic of China

Porous organic cages(POCs)with permanent porosity and excellent host–guest property hold great potentials in regulating ion transport behavior,yet their feasibility as solid-state electrolytes has never been testified in a practical ***,we design and fabricate a quasi-solid-state electrolyte(QSSE)based on a POC to enable the stable operation of Li-metal batteries(LMBs).Benefiting from the ordered channels and cavity-induced anion-trapping effect of POC,the resulting POC-based QSSE exhibits a high Li+transference number of 0.67 and a high ionic conductivity of 1.25×10^(−4) S cm^(−1) with a low activation energy of 0.17 *** allow for homogeneous Li deposition and highly reversible Li plating/stripping for over 2000 *** a proof of concept,the LMB assembled with POC-based QSSE demonstrates extremely stable cycling performance with 85%capacity retention after 1000 ***,our work demonstrates the practical applicability of POC as SSEs for LMBs and could be extended to other energy-storage systems,such as Na and K batteries.

关键词： Porous organic cage Cavity-induced anion-trapping Quasi-solid-state electrolyte Homogeneous Li+flux Lithium metal battery

Integration of Electrical Properties and Polarization Loss Modulation on Atomic Fe–N‑RGO for Boosting Electromagnetic Wave Absorption

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2025年第2期17卷 517-532页

作者： Kaili Zhang yuefeng Yan Zhen Wang Guansheng Ma Dechang jia Xiaoxiao Huang yu Zhou State Key Laboratory of Precision Welding&Joining of Materials and Structures Harbin Institute of TechnologyHarbin 150001People’s Republic of China School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001People’s Republic of China MIIT Key Laboratory of Advanced Structural‑Functional Integration Materials&Green Manufacturing Technology Harbin Institute of TechnologyHarbin 150001People’s Republic of China

Developing effective strategies to regulate graphene’s conduction loss and polarization has become a key to expanding its application in the electromagnetic wave absorption(EMWA)*** on the unique energy band structure of graphene,regulating its bandgap and electrical properties by introducing heteroatoms is considered a feasible ***,metal-nitrogen doping reduced graphene oxide(M–N-RGO)was prepared by embedding a series of single metal atoms M–N_(4) sites(M=Mn,Fe,Co,Ni,Cu,Zn,Nb,Cd,and Sn)in RGO using an N-coordination atom-assisted *** composites had adjustable conductivity and polarization to optimize dielectric loss and impedance matching for efficient EMWA *** results showed that the minimum reflection loss(RL_(min))of Fe–N-RGO reaches−74.05 dB(2.0 mm)and the maximum effective absorption bandwidth(EAB_(max))is 7.05 GHz(1.89 mm)even with a low filler loading of only 1 wt%.Combined with X-ray absorption spectra(XAFS),atomic force microscopy,and density functional theory calculation analysis,the Fe–N_(4) can be used as the polarization center to increase dipole polarization,interface polarization and defect-induced polarization due to d-p orbital hybridization and structural ***,electron migration within the Fe further leads to conduction loss,thereby synergistically promoting energy *** study demonstrates the effectiveness of metal-nitrogen doping in regulating the graphene′s dielectric properties,which provides an important basis for further investigation of the loss mechanism.

关键词： Electromagnetic wave absorption Fe-N-RGO Dipole polarization Conduction loss Impedance matching

6×900/75mm^2大截面导线架线施工工艺及工器具的研究

在线全文

学校读者我要写书评

暂无评论

华东电力 2014年第9期42卷 1852-1857页

作者：徐奋虞佳旻上海送变电工程公司上海200235

近年来,特高压直流线路工程开始采用6×JL/G2A-900/75大截面钢芯铝绞线,以提高线路的输电容量。但大截面导线的施工经验是相对欠缺的,通过对相关配套施工工艺以及大轮径张力机、高强轻型挂胶滑车、网套联接器、导线卡线器、牵引绳等施... 详细信息

近年来,特高压直流线路工程开始采用6×JL/G2A-900/75大截面钢芯铝绞线,以提高线路的输电容量。但大截面导线的施工经验是相对欠缺的,通过对相关配套施工工艺以及大轮径张力机、高强轻型挂胶滑车、网套联接器、导线卡线器、牵引绳等施工工器具的开发研究,有效解决了六分裂900/75 mm2导线架线施工的难题,确保了施工质量及安全目标的实现。

关键词：特高压大截面导线施工工艺工器具

Experimental Observing Damage Evolution in Cement Pastes Exposed to External Sulfate Attack by in situ X-ray Computed Tomography

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2025年第1期40卷 164-170页

作者： WU min CAO Kailei XIAO Weirong yu Zetai CAO Jierong DING Qingjun LI Jinhui China Railway Construction Corporation Harbour and Channel Engineering Bureau Group Co. LTDZhuhai 519000China Con-struction Headquarters of Zhoushan Liuheng Bridge Phase II Project Zhoushan 316000China China Railway Construction Bridge En-gineering Bureau Group Co. LTDTianjin 300000China State Key Laboratory of Silicate Material for Architecture(Wuhan University of Technology) Wuhan 430070China College of Materials Science and Engineering Wuhan Textile UniversityWuhan 430200China

The paper presents experimental investigation results of crack pattern change in cement pastes caused by external sulfate attack(ESA).To visualize the formation and development of cracks in cement pastes under ESA,an X-ray computed tomography(X-ray CT)was used,i e,the tomography system of Zeiss Xradia 510 *** results indicate that X-CT can monitor the development process and distribution characteristics of the internal cracks of cement pastes under ESA with attack *** addition,the C3A content in the cement significantly affects the damage mode of cement paste specimens during sulfate *** damage of ordinary Portland cement(OPC)pastes subjected to sulfate attack with high C3A content are severe,while the damage of sulfate resistant Portland cement(SRPC)pastes is much smaller than that of OPC ***,a quadratic function describes the correlation between the crack volume fraction and development depth for two cement pastes immermed in sulfate solution.

关键词： concrete external sulfate attack damage evolution situ X-ray computed tomography