论城市竞争力及评价方法和程序

本文对国内外"竞争力"辨析的基础上,探讨了城市竞争力的概念。其结论是:城市竞争力是指一定竞争环境中,一个城市在发展过程中所具有的吸引、争夺、拥有、控制和转化资源,以创造价值或财富,提高居民生活水平和城市可持续发展的能力。在城市竞争力概念和城市竞争力影响因素的"环境学派"、"资源学派"和"能力学派"基础上,本文分析了城市竞争力的一般评价方法:区域经济学方法、基准法和SWOT方法。最后总结了城市竞争力评价的一般程序。     

游客量对炳灵寺第128窟微环境影响初步研究

通过对炳灵寺石窟第128窟连续一年的微环境监测数据分析,结合游客参观统计,探究了游客量对炳灵寺第128窟微环境的影响;其中CO₂浓度与游客量呈正相关,窟内外温差越大,其衰减越快。洞窟温度升高与游客量呈一定程度正相关,温度增量主要为正值,负值与气象条件相关,温度的衰减与温度增量及窟内外温差正相关。窟内相对湿度变化较为复杂,监测期间游客参观对相对湿度影响在-5%～10%范围内,以降低窟内相对湿度为主。研究结果表明,目前的开放模式有助于CO₂浓度衰减,可适当扩大每批次参观人数至10人左右,以应对大客流状况;注重旅游旺季特别是5月、9月下旬至10月中旬时间段洞窟内相对湿度变化的监测,做好游客管理和洞窟相对湿度控制应对措施。本研究对于炳灵寺石窟第128窟及其他相似洞窟的旅游开放管理具有一定指导意义。     

Future Prospects for Population Development in Shanghai

This study analyses the future goals of population development in Shanghai from the viewpoint of population carrying capacity and ecological footprint. The population carrying capacity is one of the fundamental factors researchers and policy-makers need to take into account in managing and planning the development of a country or a region. This study focuses on the case of Shanghai, based on previous ecological footprint analysis, and builds a comprehensive index evaluation model. By applying basic principles of multi-goal decision-making analysis and operating methods of system dynamics, it calculates population carrying capacity corresponding to different standards that resource-economic factors can support. It further explores issues related to population change in the metropolis and relevant policy measures.     

MOMENT RESISTING WELDED CONNECTIONS: AN EXTENSIVE REVIEW OF DESIGN PRACTICE AND EXPERIMENTAL RESEARCH IN USA,JAPAN AND EUROPE

Welded connections, widely used in seismic moment resisting frames (MRFs) in USA, Japan and Europe, have been extensively investigated during the 1990s in order to improve their performance under severe earthquakes. In order to correctly evaluate the results of experimental research on welded connections, the differences among the American, Japanese and European current practices in designing the frame structural systems and in detailing the beam-to-column connections should be firstly appraised. In this paper, the major aspects characterising the USA, Japan and Europe design practice in moment resisting welded connections are reported, the differences are underlined and the main issues recently addressed in experimental research are reviewed. Among the several parameters which affect the connection performance, attention is focused on the effect of the beam cross-section size. Thus conclusions are drawn in terms of plastic rotation capacity as dependant on the beam size.     

A SUMMARY OF RESULTS OF SIMULATED SEISMIC LOAD TESTS ON REINFORCED CONCRETE BEAM-COLUMN JOINTS,BEAMS AND COLUMNS WITH SUBSTANDARD REINFORCING DETAILS

The results of some simulated seismic load tests on reinforced concrete one-way interior and exterior beam-column joints with substandard reinforcing details typical of buildings constructed in New Zealand before the 1970s are described. The tests were conducted using both deformed and plain round longitudinal reinforcement. The interior beam-column joint cores lacked transverse reinforcement and the longitudinal bars passing through the joint core were poorly anchored. The exterior beam-column joint units contained very little transverse reinforcement in the members and in the joint core. In one exterior beam-column joint unit the beam bar hooks were not bent into the joint core. That is, the hooks at the ends of the top bars were bent up and the hooks at the ends of the bottom bars were bent down. This anchorage detail was common in many older buildings constructed before the 1970s. In the other exterior beam-column joint unit the hooks at the ends of the bars were bent into the joint core as in current practice. The improvement in performance of the joint with beam bars anchored according to current practice is demonstrated. In addition, tests were conducted on interior joints with lap splices in the beam longitudinal reinforcement bars near the column face. The tests were conducted using both deformed and plain round longitudinal reinforcement. Tests were also conducted on columns with plain round bar longitudinal reinforcement and inadequate transverse reinforcement.

The reinforcing details were close to identical to those in an existing seven storey reinforced concrete building that was designed and built in New Zealand in the late 1950s.

The test results give an indication of the performance of beam-column joints and members with the above now out-of-date reinforcing details.

The test results reported are a summary of results reported in a number of publications written since 1994.     

METHODOLOGY FOR THE PROBABILISTIC ASSESSMENT OF q FACTORS. A DAMAGE INDEX APPROACH

The objective of the present work is to present a methodology for the identification of relevant limit states, namely ultimate limit states leading to structural collapse, and for the assessment of design q factors (or force reduction factors) for reinforced concrete structures under seismic loading. It follows a probabilistic approach based on damage indices. The utilised nonlinear models, as well as the damage indices, which are those proposed by Miner and by Park and Ang, are.described. The methodology of analysis is presented emphasising its probabilistic characteristics. Some parametric studies are carried out, including the analysis of one regular plane frame reinforced concrete structure, designed for three different ductility classes (those proposed by Eurocode 8) and assuming different q factors in design. Results show how the chosen damage indices can be used as parameters to characterise the structural response and how the proposed methodology can be used to assess the design q factors. It is also shown that, for moderate seismic input, the three ductility classes are essentially equivalent in terms of maximum damage indices, but that for higher seismic levels the differences are evident, justifying the use of different q factors.     

DUCTILITY AND LOAD CARRYING CAPACITY PREDICTION OF STEEL BEAM-TO-COLUMN CONNECTIONS UNDER CYCLIC REVERSAL LOADING

Abstract

The economy and reliability of steel-framed buildings in seismic areas depend basically on the hysteretic behaviour of its individual components, such as members and joints. With reference to the latter, despite the recent semi-continuous frame approach (which appears generally very convenient for the design of low- and medium-rise steel buildings), the present state of knowledge does not allow for a complete understanding of the behaviour and the low-cycle fatigue life of beam-to-column connections under dynamic loads.

This paper presents a criterion for the definition of the low-cycle fatigue strength of steel connections, and proposes two approaches for the design of steel frames in seismic zones via the assessment of the fatigue damage, which is evaluated alternatively on the basis of either the ductility or of the load carrying capacity.     

快速定量装车站液压系统设计

该文首先介绍了快速定量装车系统的结构及工作原理,然后对其液压系统进行了负荷特性分析及系统流量计算,并在此基础上进行了快速定量装车站液压系统设计。该设计有效的满足了装车站高效率、高精度和重载荷的需求,并在现场应用中取得了良好的使用效果。     

Adaptation Machines and the Parasitic Politics of Life in Jamaican Disaster Resilience

This paper unpacks a politics of life at the heart of community‐based disaster management to advance a new understanding of resilience politics. Through an institutional ethnography of participatory resilience programming in Kingston, Jamaica, I explore how staff in Jamaica's national disaster management agency engaged with a qualitatively distinct form of collective life in Kingston's garrison districts. Garrison life has been shaped by the confluence of political economic, cultural, geopolitical force relations, which creates a hyper‐adaptive life that exceeds the techniques and rationalities of neoliberal disaster resilience. I draw on autonomist Marxist and Deleuzian readings of biopolitics to identify a new subject of disaster politics that I call, after Deleuze and Guattari, “adaptation machines”, decentralized apparatuses of capture that are parasitically reliant on the population's immanent adaptive capacities. The concept of adaptation machines enables us to envision resilience politics as a struggle over how to appropriate vulnerable peoples’ world‐forming constituent power.     

Local gender contract and adaptive capacity in smallholder irrigation farming: a case study from the Kenyan drylands

This article presents the local gender contract of a smallholder irrigation farming community in Sibou, Kenya. Women's role in subsistence farming in Africa has mostly been analyzed through the lens of gender division of labor. In addition to this, we used the concept of ‘local gender contract’ to analyze cultural and material preconditions shaping gender-specific tasks in agricultural production, and consequently, men's and women's different strategies for adapting to climate variability. We show that the introduction of cash crops, as a trigger for negotiating women's and men's roles in the agricultural production, results in a process of gender contract renegotiation, and that families engaged in cash cropping are in the process of shifting from a ‘local resource contract’ to a ‘household income contract.’ Based on our analysis, we argue that a transformation of the local gender contract will have a direct impact on the community's adaptive capacity climate variability. It is, therefore, important to take the negotiation of local gender contracts into account in assessments of farming communities' adaptive capacity.