检索结果-南通市图书馆

在线全文

学校读者我要写书评

暂无评论

数字消费的劳动力资源再配置效应

东北师大学报（哲学社会科学版） 2025年第1期 32-47页

作者：刘伟江郝一哲李京京吉林大学数量经济研究中心吉林长春130012 吉林大学商学与管理学院吉林长春130012 吉林省科学技术信息研究所吉林长春130033

优化劳动力资源配置是人口红利消退趋势下提升全要素生产率的高质量方案。本文将数字消费纳入一个多部门竞争均衡的资源错配框架中,借助理论模型实证检验了以平台经济为代表的数字消费对劳动力资源错配的非线性影响及机制。研究表明:第... 详细信息

优化劳动力资源配置是人口红利消退趋势下提升全要素生产率的高质量方案。本文将数字消费纳入一个多部门竞争均衡的资源错配框架中,借助理论模型实证检验了以平台经济为代表的数字消费对劳动力资源错配的非线性影响及机制。研究表明:第一,数字消费规模对劳动力资源错配呈现出显著的“倒U形”非线性影响,且我国数字消费已处于对劳动力再配置的优化阶段,该结论经一系列检验后依然具有稳健性。第二,数字消费对劳动力资源错配的影响随着地理区位、环境规制以及资本配置效率的不同呈现出显著的异质性。第三,市场化进程、产业集聚以及政府经济目标是调节数字消费规模对劳动力资源错配“倒U形”非线性关系的重要机制。其中,市场化进程的深入会导致极值点向右偏移,并强化非线性关系;产业集聚水平、政府经济目标的提高使极值点向左移动,并弱化非线性关系。研究结果丰富了数字时代劳动力再配置理论,为发展新质生产力提出了新方案和新思路。

关键词：数字消费平台经济劳动力资源错配资源再配置

Analysis of Speciali.ed Production of Transaction Services Based on Essential Services Quantity

维普期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2017年第5期22卷 529-538页

作者： li.Wang Yueting Chai yi.li. Department of Automation Tsinghua University

The speciali.ed production of e-commerce transaction systems is an important research topic, which is of great significance for evaluating the development level and forecasting the development direction of e-commerce. However, there is a certain disparity between the current mainstream research model and reali.y, which leads to a deviated result. This paper puts forward a definition of ＂transaction efficiency＂ based on essential transaction services and establi.hes a model of the middleman＇s speciali.ed production decision of transaction services. The research result shows that （1） transaction efficiency plays an important role in improving the middleman＇s speciali.ed production level, （2） only when the transaction efficiency is higher than a certain threshold will the distribution middleman appear, and （3） the degree of economic speciali.ation, price of commodities and transaction services, and other associated factors also affect the evolution of e-commerce transaction systems.

关键词： essential services quantity transaction efficiency transaction service speciali.ed productionoptimization model

Machine learning models for the secondary Bjerknes force between two insonated bubbles

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2021年第1期37卷 35-46,I0001页

作者： Haiyan Chen Yue Zeng yi.li School of Material and Energy Guangdong University of TechnologyGuangzhou510006China School of Mathematics and Statistics University of SheffieldSheffieldS37RHUK

The secondary Bjerknes force plays a significant role in the evolution of bubble ***,due to the complex dependence of the force on multiple parameters,it is highly non-trivial to include its effects in the simulations of bubble *** this paper,machine learning is used to develop a data-driven model for the secondary Bjerknes force between two insonated bubbles as a function of the equili.rium radii of the bubbles,the distance between the bubbles,the ampli.ude and the center frequency of the ultrasound *** sign of the force may change with the phase difference between the oscillating ***,the magnitude of the force varies over several orders of magnitude,which poses a serious challenge for the usual machine learning *** overcome this difficulty,the magnitudes and the signs of the force are separated and modelled separately.A nonli.ear regression is obtained with a feed-forward network model for the logarithm of the magnitude,whereas the sign is modelled by a support-vector machine *** principle,the practical aspects related to the training and vali.ation of the machine models are *** predictions from the models are checked against the values computed from the Keller-Miksis *** results show that the models are extremely efficient while providing accurate estimate of the *** models make it computationally feasible for the future simulations of the bubble clusters to include the effects of the secondary Bjerknes force.

关键词： Bubble clusters Secondary Bjerknes force Machine learning Neural networks Support-vector machine Numerical simulations

Connectivity-preserving consensus of nonli.ear switched multi-agent systems with predefined accuracy

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

Science China(Technological Sciences) 2023年第6期66卷 1769-1783页

作者： yi.JiaLe li.Jing CHEN XueMiao School of Mathematics and Statistics Xidian UniversityXi’an 710716China

This paper focuses on the connectivity-preserving consensus of nonli.ear switched multi-agent systems with predefined ***,a unified error transformation is adopted to preserve the initial interaction pattern determined by agents’li.ited communication ranges and initial ***,the so-called congelation of variables method is used to handle the unknown aperiodically time-varyi.g parameters,which are fast-varyi.g in an unknown compact set with only their radii known a *** addition,a series of continuously differentiable functions are incorporated into the Lyapunov function to design the *** on Lyapunov stabili.y theory,the proposed control algorithm guarantees that the consensus errors converge with a predefined accuracy,whereas most existing connectivity-preserving results can only ensure uniform ultimate ***,all closed-loop signals remain ***,two simulations are provided to vali.ate the effectiveness of the proposed control protocol.

关键词： connectivity preservation predefined accuracy nonli.ear switched multi-agent systems aperiodically time-varyi.g parameters nonstrict-feedback structure

同方期刊数据库

非静水压环境对U_(3)O_(8)高压拉曼声子行为的影响

在线全文

学校读者我要写书评

暂无评论

光谱学与光谱分析 2025年第1期45卷 59-65页

作者：王艺佳吴彬彬刘静仪房雷鸣刘本琼雷力四川大学原子与分子物理研究所四川成都610065 中国工程物理研究院核物理与化学研究所四川绵阳621022

八氧化三铀(U_(3)O_(8))是动力学和热力学最稳定的铀氧化物。研究U_(3)O_(8)的高压相稳定性和高压声子行为对其在核工业、催化剂等领域的应用具有重要参考价值。由于铀原子([Rn]5f^(3)6d^(1)7s^(2))和氧原子([He]2s^(2)2p^(4))核外电子... 详细信息

八氧化三铀(U_(3)O_(8))是动力学和热力学最稳定的铀氧化物。研究U_(3)O_(8)的高压相稳定性和高压声子行为对其在核工业、催化剂等领域的应用具有重要参考价值。由于铀原子([Rn]5f^(3)6d^(1)7s^(2))和氧原子([He]2s^(2)2p^(4))核外电子结构存在显著差异,因此很难通过同步辐射X射线衍射技术探测高压下铀氧化合物中U-O键合的细微变化。然而拉曼光谱对高压下U-O键合变化非常敏感,它能揭示物质在高压下包括键合或者化学计量等方面的重要信息。目前对U_(3)O_(8)高压结构相变的研究通常聚焦于静水压环境,而非静水压环境对U_(3)O_(8)高压相变的影响尚未得到深入研究。该研究基于金刚石对顶砧的高压拉曼散射技术探究了静水压和非静水压环境对正交α-U_(3)O_(8)高压相变与声子行为的影响。研究表明,静水压(8.1 GPa)和非静水压(8.2 GPa)条件下α-U_(3)O_(8)高压相变起始压力很接近。但由于非静水压环境中样品内的微区偏应力较大,因此非静水压环境中U_(3)O_(8)高压相变结束压力(16.4 GPa)比静水压环境中相应压力(18.5 GPa)约低2~3个GPa。同时本文给出了两对比实验中主拉曼模的一阶压力系数与Mode-Grüneisen参数γ。对比分析可知,高压相变前静水压条件下各主模零压下的一阶压力系数绝对值|dω/d P|几乎均大于非静水压条件下的相应值,这表明相变前非静水压环境中各拉曼模对压力响应不明显;一旦高压相变开始,由于较大微区偏应力的存在极大程度增强了铀氧原子外层电子的耦合作用,故相变后非静水压下压力系数绝对值显著增大。零压下B(6)2模的γ值最小,因此对外部扰动有更积极的响应。此外室温加压时A(3)2和A(4)2模(代表沿a轴氧原子的振动)的一阶压力系数通常小于B(4)2和B(6)2模(代表bc面内氧原子的位移),这表明α-U_(3)O_(8)高压相变前a轴比b、c轴更难被压缩。该工作深入探究了静水压和非静水压环境对α-U_(3)O_(8)高压相变的影响,为了解α-U_(3)O_(8)高压相稳定性和晶格动力学行为提供了重要参考。

关键词： U_(3)O_(8) 高压拉曼光谱高压相变非静水压

Establi.hment and evaluation of a co-effect structure with thermal concentration-rotation function in transient regime

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2020年第8期29卷 342-348页

作者： yi.yi.li.Hao-chun Zhang School of Energy Science and Engineering Harbin Institute of TechnologyHarbin 150001China

The advanced heat flux manipulating structures inspired by TO-based spatial mapping have aroused wide interests owing to huge potential in high-efficient thermal energy ***,most researches are li.ited to the reali.ation of single function in one specific structure and appropriate evaluation of the energy transfer process is relatively *** this work,based on time-dependent two-dimensional heat conduction equation,a co-effect structure capable of accompli.hing concentration and rotation functions simultaneously is establi.hed and vali.ated by finite element simulations compared with the conventional single concentrator and singe *** addition,from the perspective of thermodynamics,the transformed local entropy production rate and total entropy production are theoretically derived and appli.d to evaluate the quali.y of energy transfer *** proposed co-effect structure can help to explore other potential mass/flux manipulating devices and the evaluation method is valuable for the further manufacturing as well as optimization of these devices in engineering appli.ations.

关键词： transformation thermodynamics thermal concentration-rotation transformed entropy production transient regime

Full-scale appli.ation and performance of a new multi-self-reflow decentrali.ed Wastewater treatment device: Impact of hydrauli. and pollutant loads

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2023年第9期131卷 37-47页

作者： Xiang li.Yong Huang yi.Guo Wei li.Yuqing li School of Environmental Science and Engineering Suzhou University of Science and TechnologySuzhou 215009China Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment Suzhou University of Science and TechnologySuzhou 215009China Suzhou SuJing Environmental Engineering Company Jiangsu Suzhou Purification Group Technology CompanySuzhou 215009China

Decentrali.ed treatment of wastewater in rural areas usually has several challenges,which include large fluctuations in pollutant concentration and water quantity,compli.ated operation and maintenance of conventional biochemical treatment equipment,resulting in poor stabili.y and a low compli.nce rate of the wastewater treatment *** order to solve the above problems,a new integration reactor is designed,which uses gravity and aeration tail gas self-reflux technology to reali.e the reflux of sludge and the nitrification li.uid,*** feasibili.y and operation characteristics of its appli.ation for decentrali.ed wastewater treatment in rural areas are *** results demonstrated that,under constant influent,the device showed strong tolerance to the shock of pollutant *** chemical oxygen demand,NH_(4)^(+)-N,total nitrogen and total phosphorus fluctuated in the ranges of 95–715 mg/L,7.6–38.5 mg/L,9.32–40.3 mg/L and 0.84–4.9 mg/L,*** corresponding effluent compli.nce rates were 82.1%,92.8%,96.4%and 96.3%,*** the wastewater discharge was non-constant and the maximum single-day Qmax/Qmin reached 5,all indicators of the effluent met the relevant discharge *** integrated device also demonstrated high phosphorus enrichment levels in its anaerobic zone;the concentration of phosphorus reached a maximum of 26.9 mg/L,which created a good environment for phosphorus *** microbial community analysis showed that sludge digestion,denitrification,and phosphorus-accumulating bacteria all played an important role in pollutant treatment.

关键词： Decentrali.ed wastewater treatment Integrated device Self-reflux technology Load shock Operational characteristics

The Support of a Refinable Vector Satisfyi.g an Inhomogeneous Refinement Equation

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,Engli.h Series 2010年第4期26卷 691-698页

作者： Song li.yi.SHEN Department of Mathematics Zhejiang University Hangzhou 310027 P. R. China

In this paper, we investigate the support of a refinable vector satisfyi.g an inhomoge- neous refinement equation. By using some methods introduced by So and Wang, an estimate is given for the support of each component function of a compactly supported refinable vector satisfyi.g an inhomogeneous matrix refinement equation with finitely supported masks.

关键词： support inhomogeneous refnement equation refinable vector

The Exact Traveli.g Wave Solutions to Two Integrable KdV6 Equations

在线全文

学校读者我要写书评

暂无评论

Chinese Annals of Mathematics,Series B 2012年第2期33卷 179-190页

作者： Jibin li.yi.ZHANG Department of Mathematics Zhejiang Normal UniversityJinhua 321004ZhejiangChina Faculty of Science Kunming University of Science and TechnologyKunming 200062China

The exact expli.it traveli.g solutions to the two completely integrable sixthorder nonli.ear equations KdV6 are given by using the method of dynamical systems and Cosgrove's *** is proved that these traveli.g wave solutions correspond to some orbits in the 4-dimensional phase space of two 4-dimensional dynamical *** orbits li. in the intersection of two level sets defined by two first integrals.

关键词： KdV6 equation Exact traveli.g wave solution Soli.ary wave solution Quasi-periodic wave solution