期刊文献+
共找到12篇文章
< 1 >
每页显示 20 50 100
劳动力异质性及其流动——兼论我国劳动力从自发流动向自主流动转变 被引量:12
1
作者 焦斌龙 孙晓芳 《当代经济研究》 CSSCI 北大核心 2013年第9期61-66,共6页
劳动力的异质性是客观存在的,在不同的社会阶段表现形式不同,随着社会的发展,劳动力异质性的内涵将会不断丰富。我国在人口红利阶段,劳动力需求的不足掩盖了劳动力的异质性,劳动力被同质化。随着人口红利的逐步减弱和消失,劳动力的异质... 劳动力的异质性是客观存在的,在不同的社会阶段表现形式不同,随着社会的发展,劳动力异质性的内涵将会不断丰富。我国在人口红利阶段,劳动力需求的不足掩盖了劳动力的异质性,劳动力被同质化。随着人口红利的逐步减弱和消失,劳动力的异质性逐步显现出来。这种变化反映到劳动力流动中,就呈现出劳动力流动由自发流动向自主流动转变。 展开更多
关键词 劳动力异质性 劳动力流动 自发流动 自主流动
下载PDF
二元制度下中国农村剩余劳动力自发流动模型的建立及其政策含义 被引量:5
2
作者 衣光春 徐蔚 《西北人口》 2004年第2期12-16,共5页
本文利用人力资本投资的理论,建立了一个二元制度背景下的中国农村劳动力自发流动模型,指出影响农民做出外出务工决策的主要因素是其流入城市的净收益现值,并对决定这一现值的各变量进行了考察。作者认为二元的经济和社会体制降低了农... 本文利用人力资本投资的理论,建立了一个二元制度背景下的中国农村劳动力自发流动模型,指出影响农民做出外出务工决策的主要因素是其流入城市的净收益现值,并对决定这一现值的各变量进行了考察。作者认为二元的经济和社会体制降低了农民的流动和迁移意愿,限制了农民的外出。最后作者提出了短期内促进农民工流动和长期内保证农民迁移的政策建议。 展开更多
关键词 二元制度 农村剩余劳动力 农村劳动力自发流动模型 政策含义
下载PDF
“桥梁”与“安全”交叠:中越边境人口跨界自发流动及其双重效应——基于对云南H县的调查分析
3
作者 陆海发 李娜 《楚雄师范学院学报》 2023年第4期60-68,共9页
边境是国家治理的一个特殊区域,其人口跨界自发流动与国家治理的逻辑紧密关联。研究通过对中越边境云南段H县的实地调查,发现这一区域的人口跨界自发流动不仅类型多样,而且其在人口流向、人口规模变化及合法性等方面呈现出一些突出特点... 边境是国家治理的一个特殊区域,其人口跨界自发流动与国家治理的逻辑紧密关联。研究通过对中越边境云南段H县的实地调查,发现这一区域的人口跨界自发流动不仅类型多样,而且其在人口流向、人口规模变化及合法性等方面呈现出一些突出特点。同时,其对国家边境秩序的影响呈现出双重效应:一方面发挥着“桥梁”作用,有利于增进毗邻国家间的利益;另一方面对国家边境的治理也构成“安全”挑战,特别是在疫情防控期间,其引发的卫生安全成为边境治理的最大挑战。在边境人口跨界自发流动的治理实践中,需要巧妙地在“桥梁”与“安全”所交叠的双重效应下维持平衡,以增进毗邻国家及人民之间的共同福祉。 展开更多
关键词 边境 跨界自发流动 桥梁 安全
下载PDF
音速喷嘴内水蒸气自发凝结流动自激振荡和分歧现象 被引量:5
4
作者 王超 王刚 丁红兵 《天津大学学报(自然科学与工程技术版)》 EI CSCD 北大核心 2016年第11期1113-1120,共8页
气体在喷嘴中流动伴有很大的温降,会使其中的水蒸气发生凝结,并对其计量产生影响.针对音速喷嘴中过热水蒸气自发凝结流动产生的非稳态自激振荡和流动分歧现象,建立了考虑黏性的水蒸气自发凝结数值模型;根据凝结诱导的气动激波的振荡幅... 气体在喷嘴中流动伴有很大的温降,会使其中的水蒸气发生凝结,并对其计量产生影响.针对音速喷嘴中过热水蒸气自发凝结流动产生的非稳态自激振荡和流动分歧现象,建立了考虑黏性的水蒸气自发凝结数值模型;根据凝结诱导的气动激波的振荡幅度将自激振荡分为3种不同的模式,其中模式Ⅲ的压力波动会波及喉部上方,且会出现非对称流动分歧现象,而模式Ⅰ中气动激波仅在平衡位置附近小幅度振荡;最后研究了自激振荡对喷嘴的质量流量的影响,并给出了相应的修正系数,最小值为0.988,需要加以重视. 展开更多
关键词 音速喷嘴 自发凝结流动 自激振荡模式 流动分歧 质量流量
下载PDF
基于S2流面方法的自发凝结湿蒸汽流动数值研究 被引量:1
5
作者 李得英 宋彦萍 +1 位作者 付云峰 陈焕龙 《工程热物理学报》 EI CAS CSCD 北大核心 2016年第2期295-299,共5页
基于欧拉S2流面计算程序,发展了一种Eulerian/Eulerian模型的湿蒸汽自发凝结流动数值计算方法,并将其应用于Moses-Stein喷管和某三级低压蒸汽透平性能预测。结果表明,该方法能够较准确地计算喷管中蒸汽的自发凝结现象,与实验结果吻合良... 基于欧拉S2流面计算程序,发展了一种Eulerian/Eulerian模型的湿蒸汽自发凝结流动数值计算方法,并将其应用于Moses-Stein喷管和某三级低压蒸汽透平性能预测。结果表明,该方法能够较准确地计算喷管中蒸汽的自发凝结现象,与实验结果吻合良好;能够合理预测低压蒸汽透平中湿蒸汽对气动参数的影响及气动参数的真实分布规律,为蒸汽透平提供了快速、准确的气动设计方法和工具。 展开更多
关键词 低压蒸汽透平 自发凝结流动 Eulerian/Eulerian模型 S2流面计算方法
原文传递
前置式超声速旋流分离器设计与凝结特性分析
6
作者 张卫兵 《当代化工》 CAS 2016年第8期1892-1895,1899,共5页
针对天然气在长距离管道输送过程中,所含水蒸汽杂质会凝结成液态水的问题,通过运用动力学原理与液滴成核生长理论,开发设计了一种全新的前置式超声速旋流脱水装置。利用CFD中的用户自定义接口建立了含湿天然气的凝结流动模型,数值分析... 针对天然气在长距离管道输送过程中,所含水蒸汽杂质会凝结成液态水的问题,通过运用动力学原理与液滴成核生长理论,开发设计了一种全新的前置式超声速旋流脱水装置。利用CFD中的用户自定义接口建立了含湿天然气的凝结流动模型,数值分析了装置内部的马赫数、过冷度、液滴成核率、液滴半径和湿度等关键凝结参数的变化规律。结果表明:所建立的三维含湿天然气的凝结流动模型可以真实描述超声速旋流分离器中的流动变化规律,为以后装置的工业应用和下一步提高分离效率提供了理论参考。 展开更多
关键词 前置式超声速分离器 自发凝结流动 数值模拟 分离效率
下载PDF
Network Fault Analysis from Passive Measurement 被引量:1
7
作者 Huang Lisheng Wang Wenyong +1 位作者 Li Changchun Lan Yunhai 《China Communications》 SCIE CSCD 2012年第5期64-74,共11页
A new passive method for automatic dis-covery and bcation of network failure is proposed. This method employs a passive measurement to collect infonmtion and events from network traffic, and em-ploys a rrodel-based re... A new passive method for automatic dis-covery and bcation of network failure is proposed. This method employs a passive measurement to collect infonmtion and events from network traffic, and em-ploys a rrodel-based reasoning system to detect and locate network faults. Measurement points are de-ployed in a backbone network to capture the traffic and then evaluate the Quality of Service (QoS) metrics of end-to-end IP conversations. A muting rrodel is al-so established for the observed network to simulate the attributes and activities of reuters and links. This muting model also deduces the muting path for each IP conversation, and thus the QoS metrics of IP con-versations are mapped into the metrics of paths. With the inforrmtion of shared links of overlapping paths and network torrography technique, the QoS metrics of links can also be estimated, and the poorly rated links are picked out as failure points. This method is imple-mented in a tool named FaultMan, which is deployed in a campus network. Test results have shown its availa-bility in rriddle-scale networks. 展开更多
关键词 passive measurement network fault lo-cation model-based reasoning
下载PDF
SDG-based Model Validation in Chemical Process Simulation 被引量:7
8
作者 张贝克 许欣 +1 位作者 马昕 吴重光 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2013年第8期876-885,共10页
Signed direct graph (SDG) theory provides algorithms and methods that can be applied directly to chemical process modeling and analysis to validate simulation models, and is a basis for the development of a software e... Signed direct graph (SDG) theory provides algorithms and methods that can be applied directly to chemical process modeling and analysis to validate simulation models, and is a basis for the development of a software environment that can automate the validation activity. This paper is concentrated on the pretreatment of the model validation. We use the validation scenarios and standard sequences generated by well-established SDG model to validate the trends fitted from the simulation model. The results are helpful to find potential problems, assess possible bugs in the simulation model and solve the problem effectively. A case study on a simulation model of boiler is presented to demonstrate the effectiveness of this method. 展开更多
关键词 model validation signed direct graph chemical process qualitative trend
下载PDF
Three dimensional free convection couette flow with transpiration cooling
9
作者 JAIN N. C. GUPTA P. 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2006年第3期340-346,共7页
Free convection flow between two vertical parallel plates with transverse sinusoidal injection of the fluid at the stationary plate and its corresponding removal by constant suction through the plate in uniform motion... Free convection flow between two vertical parallel plates with transverse sinusoidal injection of the fluid at the stationary plate and its corresponding removal by constant suction through the plate in uniform motion has been analyzed. Due to this type of injection velocity, the flow becomes three-dimensional. Analytical expressions for the velocity, temperature, skin friction and rate of heat transfer were obtained. The important characteristics of the problem, namely the skin friction and the rate of heat transfer are discussed in detail with the help of graphs. 展开更多
关键词 Couette flow Free convection Three-dimensional flow Transpiration cooling Transverse sinusoidal injection
下载PDF
Effects of continuous intermedin infusion on blood pressure and hemodynamic function in spontaneously hypertensive rats 被引量:9
10
作者 Ying Yuan Xi Wang +3 位作者 Qiang Zeng Hong-Mei Wu Yong-Fen Qi Chao-Shu Tang 《Journal of Geriatric Cardiology》 SCIE CAS CSCD 2012年第1期17-27,共11页
Objective To examine the effects of exogenously administered intermedin (IMD,adrenomedullin-2) on arterial blood pressure,cardiac function and the cardiovascular IMD receptor system in spontaneously hypertensive ra... Objective To examine the effects of exogenously administered intermedin (IMD,adrenomedullin-2) on arterial blood pressure,cardiac function and the cardiovascular IMD receptor system in spontaneously hypertensive rats (SHRs) as well as to investigate the associated mechanisms.Methods Thirteen week-old male rats were divided in Wistar Kyoto (WKY) group (n =12),SHR group (n =12),IMD group (SHRs infused with IMD 1-47 500 ng/kg per hour,n =12),and ADM group (SHRs infused with adrenomedullin 500 ng/kg per hour,n =12).Results A two-week continuous administration of low dose IMD 1-47 via mini-osmotic pumps markedly reduced blood pressure,the maximal rates of increase and decrease of left-ventricle pressure development (LV ± dp/dtmax),left ventricular systolic pressure and heart rate in SHRs.Furthermore,IMD also inhibited protein over-expression of cardiovascular IMD receptors,myocardial Receptor Activity-Modifying Proteins (RAMP1 and RAMP2),aortic RAMP1,RAMP2,RAMP3,and calcitonin receptor-like receptor (CRLR);suppressed up-regulation of aortic RAMP1,RAMP2,RAMP3 and CRLR gene expression; and markedly elevated the mRNA abundance of myocardial atrial natriuretic peptide (ANP) and myocardial brain natriuretic peptide (BNP).Additionally,IMD 1-47 administration in SHRs increased aortic cAMP concentration and reduced myocardial cAMP concentration.Conclusion These findings support the speculation that IMD,as a cardiovascular active peptide,is involved in blood pressure reduction and cardiac function amelioration during hypertension.The mechanism underlying this effect may involve IMD binding of a receptor complex formed by RAMPs and CRLR,and consequential regulation of cAMP levels and other cardiovascular active factors,such as ANP and BNP. 展开更多
关键词 INTERMEDIN Receptor activity-modifying proteins Calcitonin receptor-like receptor Mini-osmotic pumps Hemodynamicparameters Spontaneously hypertensive rats
下载PDF
Agriculture Development and Strategy in Scientific Concept of Development
11
作者 Baokun WANG 《International Journal of Technology Management》 2015年第3期35-37,共3页
This report presents the party' s congress in 2020 to ensure the completion of the goal to achieve a comprehensive well-off society, and build a moderately prosperous society that focuses on rural issues and bottlene... This report presents the party' s congress in 2020 to ensure the completion of the goal to achieve a comprehensive well-off society, and build a moderately prosperous society that focuses on rural issues and bottlenecks. After the founding of New China' s rural issues, our country has gone through a period of free flow of urban and rural in urban and rural isolation period and the interaction period. Although the performance of the various period' s rural issues are not the same, but behind it there is a profound theoretical and practical logic. It is the cumulative long-term history of this issue to become "top priority" , the scientific concept of development is put forward to solve this problem, which is to expand the boundaries of knowledge, provide methodological guidance for us to solve rural issues. Therefore, to solve three agricultural issues to thoroughly implement the scientific concept of development, we must regard development as the top priority in governing and rejuvenating the party, adhere to the overall planning of urban and rural development, adhere to the overall rural economic and social development,, and adhere to a comprehensive, coordinated and sustainable development. 展开更多
关键词 scientific concept of development rural issues ECONOMIC
下载PDF
Fluid dynamic modeling of a free piston engine with labyrinth seals 被引量:4
12
作者 Jaakko Larjola Juha Honkatukia +1 位作者 Petri Sallinen Jari Backman 《Journal of Thermal Science》 SCIE EI CAS CSCD 2010年第2期141-147,共7页
Preliminary design and simulation of a free piston engine suitable for small-scale energy production in distributed energy systems is presented in this paper.The properties,particularly the properties of gas seals of ... Preliminary design and simulation of a free piston engine suitable for small-scale energy production in distributed energy systems is presented in this paper.The properties,particularly the properties of gas seals of the engine are simulated using a simulation program developed for this case,and the results are utilized in preliminary main design parameter selection.The engine simulation program was developed by combining and modifying the source codes of the simulation and calculation programs obtained from Helsinki University of Technology,Tampere University of Technology,and Lappeenranta University of Technology.Because of the contact-free labyrinth seal used in the piston,the efficiency of the motor is lower than the efficiency of a conventional motor with oil lubricated piston rings.On the other hand,the lack of bearing losses,and the lack of losses associated with a crankshaft system and a gearbox,as well as the lack of lubrication oil expenses,compensates this effect.As a net result,this new motor would perform slightly better than the conventional one.Being completely oil-free,it is very environmentally friendly,and its exhaust gases are completely free of oil residuals which are causing problems in normal gas motors. 展开更多
关键词 free piston engine distributed energy systems SIMULATION labyrinth seal
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部