Numerical Simulation and Seismic Fragility Analysis of a Self-Centering Steel MRF with Web Friction Devices

This article presents the seismic fragility analysis of a self-centering steel moment-resisting frame (SC-MRF) with web friction devices. A detailed numerical model of the SC frame was developed using the Open System for Earthquake Engineering Simulation (OpenSees) and the elastoplastic responses of the SC-MRF were studied, including the strength degradation under cyclic loading, tendon rupture, beam buckling, bolt bearing and friction loss, etc. The proposed simulation approach is validated by comparing the simulated results with those in existing hybrid-simulation tests, quasi-static pushover test and low cyclic tests, where good agreement is observed. In addition to the well-established performance limit states (i.e., immediate occupancy, collapse prevention and global dynamic instability), two unique performance limit states (i.e., the recentering and repairable limit states) are defined for the SC-MRF. Finally, incremental dynamic analyses are conducted to evaluate the seismic fragilities regarding the five performance limit states.     

城市公园视觉景观质量的影响因素分析——以北京市紫竹院公园为例

本文将主客观评价法相结合,对北京市紫竹院公园视觉景观质量影响因素进行分析。课题组实地评价并拍摄照片,室内请评判者给照片打分评出美景度分值,请专家对主观性因子评价,与实地评价结果做一致性检验;对两种方式获取的数据进行方差分析、相关分析,并建立线型回归模型。结果表明:主观性因子的实地评价和室内问卷评价结果具有一致性;专业背景不同不影响评判者对景观美景度的评判结果;美景度与区内因子呈正相关,与区外因子呈负相关;区内的3个因子更能影响对景观的评判,其中,自然景观所占比例影响最为显著。     

Chasing Tibetan Antel Across Changtang Grassland

n the beginning of Winter, we drove along a zigzagging road across Ithe grassland of north Tibet. Music played incessantly from the vehicle while the extensive landscape stole our breath away. Above the black mountain range; golden clouds and the remaining starswere still hanging in the blue sky. Sporadic groups of antelopes, each consisting of about three to five antelopes, were rtmning beside the road.     

满铁与日本的中国东北移民

满铁作为日本“国策会社”,在日本向中国东北移民过程中,通过设置调查机关,投资成立移民执行机构,建立具有自身特色的移民组织等活动,大力支持并积极参与日本移民侵略。由于满铁与日本军方特殊的密切关系,也必然决定了其在日本对中国东北移民活动中,扮演着策划者和执行者的重要角色。     

从战地救护到社会服务——简论抗战后期中国红十字会的"复员"构想

抗战胜利后,中国红十字会进入复员时期。实际上,复员的准备工作在抗战期间即已开始,在美国红十字会的帮助下,中国红十字会拟具复员救济工作计划,在会内进行宣传发动,同时在组织机构、人员训练等方面也积极做好各项准备工作,为抗战胜利后复员时期慈善救助工作的全面展开创造了条件。     

国外女性贫困研究进展与启示——基于地理学领域的研究

男性和女性除了有生理性别差异,还有通过心理、文化和社会手段构建的社会性别差异,两者共同导致女性在健康、就业、教育、人际、资产等领域的相对弱势地位。近年,由发达国家主导的女性贫困研究热度持续增加,发展中国家研究逐渐增多,但国内研究仍在起步阶段。运用CiteSpace软件分析国外地理学领域的女性贫困研究最新进展,发现研究热点集中在基于空间差异的女性贫困研究、基于社会剥夺的女性贫困研究,以及女性减贫的政策建议研究。基于研究热点与社会性别理论,本文提炼出女性贫困研究框架体系,并总结了内在因素和外部环境共同作用的女性致贫解释机制,认为女性贫困是地区经济、文化与政治的折射。最后提出未来中国女性贫困地理研究建议,以期为推进以性别为切入点的精准扶贫做出贡献。     

Regional Coverage Maximization: Alternative Geographical Space Abstraction and Modeling

Analysis results are often found to vary with the way we abstract geographical space. When continuous geographic phenomena are abstracted, processed, and stored in a digital environment, some level of discretization is often employed. Information loss in a discretization process brings about uncertainty/error, and as a result research findings may be highly dependent on the particular discretization method used. This article examines one spatial problem concerning how to achieve the maximal regional coverage given a limited number of service facilities. Two widely used geographical space abstraction approaches are examined, the point‐based representation and the area‐based representation, and issues associated with each representation scheme are analyzed. To accommodate the limitations of the existing representation schemes, a mixed representation strategy is proposed along with a new maximal covering model. Experiments are conducted to site warning sirens in Dublin, Ohio. Results demonstrate the effectiveness of the mixed representation scheme in finding high‐quality solutions when the regional coverage level is medium or high.     

雍正惠民政策初探

康熙晚年。开始倦于政务,逐渐地失去了昔日的锐气。从而,暴露出许多社会问题。雍正在位期间,以爱民为先务,以兴利除害为己任,并确定了以“跻斯世于熙嗥之盛”和“共受升平之福”为目标的施政方略,他所推行的一系列惠民政策,都是在不增加农民负担的前提下进行的,既继承前人,又突破陈规,有所创新。这些惠民政策的实施。一方面开创了国富民殷的新局面。另一方面,也产生了程度不同的负面影响。但从总体上看,还是利大于弊的。     

宁绍平原两周时期陶瓷器生产标准化初步研究

通过对宁绍平原两周时期主要陶瓷器的CV系数统计,可知宁绍平原在西周至春秋时期,陶瓷器的生产标准化程度较低且长期未发生明显变化,规范性不足,表现出一定程度的简单与迟滞状态;至战国时则发生明显变化,陶瓷器的生产标准化程度显著提高,规范性增强,专业化程度明显提高,社会发展迅速并更趋复杂.