MODELLING OF RC MEMBERS UNDER CYCLIC BIAXIAL FLEXURE AND AXIAL FORCE

A model is proposed for the incremental force-deformation behaviour of reinforced concrete sections and members, under generalised load or deformation histories in 3D, including cyclic loading, up to ultimate deformation. At the section level the model is of the Bounding Surface type and accounts for the coupling between the two directions of bending and between them and the axial direction. For the construction of the member tangent flexibility matrix on the basis of the section tangent flexibility matrix, a piecewise-linear variation along the member is assumed for the nine terms of the tangent section flexibility matrix. Model parameters are derived on the basis of available test results for: (a) the force-deformation response under cyclic biaxial bending with normal force; (b) the hysteretic energy dissipation; (c) the secant-to-yield member stiffness, and (d) the ultimate deformation of the member under cyclic biaxial load paths.     

大城市旅游结构性增长的驱动力——基于广州和西安的比较研究

以广州和西安两个省会大城市为例,通过比较广州和西安旅游人数和旅游收入的增长差异,指出广州城市旅游呈现显著的结构性增长,而西安城市旅游的结构性增长不明显。进一步基于层次与等级的旅游供给分析框架,解释大城市旅游结构性增长的驱动力。研究表明,城市功能和地位的提升是大城市旅游的结构性增长的主导驱动力。大城市要实现旅游的结构性增长,要重点提升旅游相关的城市功能和地位,如政治、文化、现代服务业、交通、商业和城市接待功能等,并配合旅游核心要素的建设以及旅游主题和特色的营造。结构性增长是判断大城市旅游发展效率的重要指标,也是指导大城市旅游发展的重要参照。     

APPROACHES TO THE USE AND CONTROL OF FORCE THE ART OF POSING STRATEGIC PROBLEMS

There is a risk that the threat of nuclear war will be exaggerated in ways injurious to arms control and will deliver to the Soviet leadership the political returns it may be seeking. This undesirable outcome is the result of logical tricks we play on ourselves in trying to be very precise about factors like the accuracy of missiles. It is also the result of the peculiar assymmetry of the discussion of strategic matters, as all of the publicity work for Soviet weapons accomplishments is done by the press and governments of the West. Proposals for remedy would be to watch our own habits of logic, so that we do not persuade ourselves that our weapons capability or our political resolve are weak, and to force the Soviets to produce more information about their strategic capabilities.     

生产性服务业的区位驱动力与区域经济发展研究

“服务社会”中生产性服务业对区域经济发展的巨大作用,促使研究者日益关注它们的区位驱动力。在国内外研究的基础上,文章从服务生产的性质出发,探讨其隐含的区位意义,并结合对生产性服务业区位的动力机制及其对区位的作用的分析,来说明生产性服务业在区位上的集聚或扩散现象。在此基础上,阐述了在不同层面上生产性服务业的区位分布对不同国家和地区经济发展产生的影响。     

资源禀赋与区域农业剩余劳动力转移相关研究——以山东省为例

本文从区域经济学角度,以山东省为例,探讨了资源禀赋条件对农业剩余劳动力转移区域结构、转移强度、转移类型的影响,定量计算出不同资源对区域农业剩余劳动力转移压力指数,得出了相关结论。     

福建省投资环境竞争力空间过程与驱动因素分析

构建福建省地级市投资环境竞争力评价指标体系,为GIS环境地级市多边形的主要属性,以2000-2007年福建统计年鉴为主要数据源,建立时态空间数据库。通过"时空同时归一"的指标变换方法定义投资环境相对竞争力,使不同指标"等价"与引入时空统一标准,选择时间序列、截面权变显著的经因子分析确定权矩阵,进行变权法三维评价,利用序列快照模型表达、逼近福建省投资环境竞争力空间过程,通过基于数据的空间过程因子识别技术,进行驱动因素分析,为优化福建省投资环境提供调控依据。     

CALIBRATION OF FORCE REDUCTION FACTORS OF RC BUILDINGS

A comprehensive study is undertaken to assess and calibrate the force reduction factors (R) adopted in modern seismic codes. Refined expressions are employed to calculate the R factors “supply” for 12 buildings of various characteristics represent a wide range of medium-rise RC buildings. The “supply” values are then compared with the “design” and “demand” recommended in the literature. A comprehensive range of response criteria at the member and storey levels, including shear as a failure criterion, alongside a detailed modelling approach and an extensively verified analytical tool are utilised. A rigorous technique is employed to evaluate R factors, including inelastic pushover and incremental dynamic collapse analyses employing eight natural and artificial records. In the light of the information obtained from more than 1500 inelastic analyses, it is concluded that including shear and vertical motion in assessment and calculations of R factors is necessary. Force reduction factors adopted by the design code (Eurocode 8) are over-conservative and can be safely increased, particularly for regular frame structures designed to lower PGA and higher ductility levels.     

东北地区劳动力国际流动的特点、影响因素与对策研究

本文分析了东北地区劳动力国际流动数量和营业额在全国的地位、去往国别、从事的行业等特点,论述和分析了影响东北地区劳动力国际流动的有利和不利因素。针对存在的问题,提出了发展东北地区劳动力国际流动的基本对策。     

METROPOLITAN OUTMIGRATION PATTERN OF CANADIAN LABOUR FORCE ENTRANTS, 1971–76

This paper analyses the 1971 -76 metropolitan out-migration pattern of Canadian males in the labour force entrance age group. Migration is conceptualized within a three-level choice framework, and statistical inference is based on a multinomial logit model. It was found (1) that the propensity to outmigrate and the destination choice pattern vary substantially among the 23 metropolitan areas; (2) that 83 per cent of the variation in the destination choice probabilities of metropolitanward migrants can be explained by only five variables (log of distance, cultural dissimilarity, temperature, employment growth, and population size); and (3) that housing conditions are essentially the results (rather than the causes) of intermetropolitan migration .     

宁夏移民安置区剩余劳动力状态分析

农村剩余劳动力转移是当前社会各界共同关注的问题。本文就宁夏移民安置区这一特殊区域的剩余劳动力产生的背景状态、自身资源状态、输出人员的结构状态及目前的转移状态进行了分析,进而研究了影响移民区剩余劳动力转移的各种因素,提出了加速推进移民区剩余劳动力转移的五条对策,即重视移民区小城市与中心城镇的建设、加速非农产业的发展、加大对劳动力的技能培训、加强对劳务输出的组织与服务、加快体制和制度创新。     

LABOUR FORCE GROWTH IN SINGAPORE

Singapore's labour force participation rates are at high levels. Age-specific rates, especially of men, have approached those of developed countries. The current very low total fertility rate of 1.25 would have major implications for Singapore's labour supply and economy in a closed population. Multi-pronged approaches such as measures to increase fertility, increase labour force participation, and to augment the local workforce with migrants are discussed. In the context of Singapore's physical land constraint, continued growth in the labour force in the long term would be challenging. Future gross domestic product growth is likely to be more sustainable via labour productivity growth. Identifying new niche areas of growth and having a nimble and quality workforce would become more important than labour force growth.     

人口流动对边境地区人口安全的影响及机制分析

本文关注我国边境人口变动和人口流动状况,着重分析了人口流动对边境人口安全的影响机制,并探讨了边境人口流动的影响因素。研究发现,①边境县域人口总体规模稳中略降,人口增速和增量持续减少;②人口净流出已逐步成为边境人口变动主要因素;③边境人口变动与流动影响程度有明显区域差异。外流风险型地区已出现明显的人口负增长和外流,人口安全缺乏数量和质量保障;相对稳定型地区人口保持低速增长,但其人口净流出水平正不断提高,有向外流风险型转变的趋势;相对封闭增长型地区人口增长较快,但流动性较弱。各类边境地区人口流出流入呈现不同特征,并受到经济、教育、城镇化、民族、政策等不同因素影响。     

油气地缘经济与中国油气安全

本文从地缘政治观念向地缘经济观念发展的观点出发,通过对全球油气中心随时空转移和变化的分析,着重阐述了冷战以后全球形成的"石油心脏地带"和"内需求月形地带"及"外需求月形地块"的油气地缘经济格局以及有关国家围绕争夺中亚油气资源和跨国运输通道构成的内外两个三角之间的油气地缘战略竞赛,在此基础上讨论了中国油气安全所面临的处境与应采取的对策。