Introduction of structural aseismic research in China in recent four years

Introduction Greeting the coming of the 21st century, Professor HU Yu-xian and other Chinese scholars briefed the trend of earthquake engineering in China and aboard (HU, 1999; HU, ZHOU, 1999). The experiences and lessons learning from the destructive earthquakes in China and abroad in re-cent years, the damage action of the large velocity impulse in ground motion in near field in seis-mic design, numerous earthquake examples show that there are many weaknesses in aspects of earthquake p…     

A study on relation between acoustic emission and characteristic displacement field on the sample with multi en echelon structures — The theoretic and experimental explorations of strain gap

Based on the phenomena that the deformation gap was observed before the great Tangshang earthquake, this paper discusses the strain gap according to test and theory. The (strain) patterns were recorded photographically by realtime holographic interferometry and shadow optical method of caustics, as soon as the loading process started. In the meantime, the AE (acoustic emission) signals were recorded by a micro crack information storage-analysis system. According to damage theory and location of micro fracture, we have studied the stain gap and gained: a) It is necessary that strain gap appears under the condition of linear elasticity theory, and its situation is relatively stable, corresponding to stress concentration. b) Micro fractures, which appear initially at area of high stress, occur rarely at the strain gap, and their locations are finally in the zone between the stress concentration area and the strain gap, which indicate the clusters or groups. However, the major macro fracture (final rupture) started from the shadow areas, and then grew quickly towards the strain gaps, which resulted in failure of sample. Foundation item: The Dual Project of China Seismological Bureau (9691309020301), the Specialized Funds for National Key Basic Study (G1998040704), the project for the MOST under contract (2001BA601B02) and Youth Funds for applied basic study of the Science and Technology Bureau of Yunnan Province (98D019Q).     

基于T-S模糊神经网络的采空塌陷危险性判别

采空区地面塌陷的危险性判别受地质因素、采矿因素等多重因素的影响,各因素往往影响程度不同且部分因素之间又相互联系。为了能够较准确地对采空塌陷危险性进行评估,引入了T-S模糊神经网络模型。以北京西山地区采空塌陷为例,根据塌陷特点,分别选取了地质构造复杂程度、覆盖层类型、第四系覆盖层厚度、覆岩强度、煤层倾角、采深采厚比、采空区埋深、采空区空间叠置层数8项影响因素作为评价指标,并建立了分级标准。将单因素评价指标均匀线性插值作为训练样本,建立了T-S模糊神经网络判别模型。利用训练好的神经网络模型对选取的8处采空区进行评估,结果分别为:Ⅰ、Ⅱ、Ⅲ、Ⅱ、Ⅲ、Ⅱ、Ⅲ、Ⅱ,结果与实际情况吻合。研究表明,利用T-S模糊神经网络研究采空塌陷危险性是可行的。     

天山泥石流灾害的形成条件和过程特点

泥石流是天山主要自然灾害之一， 天山泥石流按触发因素可以分为暴雨型泥石流和冰川型泥石流两类。目前天山泥石流主要对效能运输造成灾害在部分地点对厂矿企业和居民点造成灾害，天山泥石流的形成和发生有其特点，掌握其形条件和过程特点有利于减轻自然灾害。     

城市居民时空行为序列模式挖掘方法

通过问卷调查获得北京市500个家庭的活动日志数据.运用序列比对方法对时空行为序列数据进行序列模式挖掘,对每类序列模式通过频繁模式挖掘出其中潜在有用的行为模式.试验结果表明,序列比对方法与频繁模式挖掘相结合在城市居民行为模式分析中应用成功,其弥补了传统数据分析方法的不足,为复杂时空行为数据的分析提供了一种新视角.     

北京市奥运期间气象灾害风险承受与控制能力分析

针对北京市奥运会期间的7种主要气象灾害(雷电、冰雹、大风、高温、暴雨、大雾和霾灾害),建立了气象灾害风险承受能力与风险控制能力评价的指标体系.经过专家评分,获取7种气象灾害的评价指标所对应的分值.利用层次分析法,计算评价指标的权重系数.最后得到7种气象灾害评价指标的加权平均值作为其风险承受能力与风险控制能力系数.利用灾害模数、经济易损模数、生命易损模数3个指标进行北京市奥运期间18个区县空间易损度区划分析.结果表明:北京市奥运会期间,高温灾害和暴雨灾害的风险承受能力与风险控制能力最弱;雷电灾害和大雾灾害的承受与控制能力中等;冰雹灾害和霾灾害较强;大风灾害最强.易损度空间差异分析表明,城区(东城区、西城区、崇文区和宣武区)、朝阳区和海淀区为高易损性区域;丰台区、石景山区、房山区、昌平区、顺义区和大兴区为中易损性区域;门头沟区、通州区、平谷区、怀柔区、密云县和延庆县为低易损性区域.     

基于PPT战略的广东省乐昌市生态旅游扶贫模式探讨

以贫困人口受益为出发点,基于有利于贫困人口发展的旅游(Pro-Poor Tourism,PPT)战略,以广东省乐昌市为例,开展适用于中国南方林区生态旅游扶贫开发的发展模式和旅游扶贫产业的发展路径研究.结果表明:1)政府部门、旅游企业、乡村社区和非营利社会组织都应在提升贫困人口参与度、减轻贫困和生态保护方面承担责任,具体...     

商丘近40 a蒸发量变化特征及原因分析

利用商丘1961-2000年小型蒸发皿蒸发量资料,分析了商丘蒸发量的变化趋势及引起蒸发量变化的因子,结果表明,商丘年、季和月蒸发量均存在明显的下降趋势,影响蒸发量变化的因子主要有风速、日照、相对湿度、水汽压等.     

The Linkage between Midwinter Suppression of the North Pacific Storm Track and Atmospheric Circulation Features in the Northern Hemisphere

The midwinter suppression(MWS) of the North Pacific storm track(NPST) has been an active research topic for decades. Based on the daily-mean NCEP/NCAR reanalysis from 1948 to 2018, this study investigates the MWS-related atmospheric circulation characteristics in the Northern Hemisphere by regression analysis with respect to a new MWS index, which may shed more light on this difficult issue. The occurrence frequency of the MWS of the upper-tropospheric NPST is more than 0.8 after the mid-1980 s. The MWS is accompanied by significantly positive sea-level pressure anomalies in Eurasia and negative anomalies over the North Pacific, which correspond to a strengthened East Asian winter monsoon. The intensified East Asian trough and atmospheric blocking in the North Pacific as well as the significantly negative low-level air temperature anomalies, lying upstream of the MNPST, are expected to be distinctly associated with the MWS. However, the relationship between the MWS and low-level atmospheric baroclinicity is somewhat puzzling.From the diagnostics of the eddy energy budget, it is identified that the inefficiency of the barotropic energy conversion related to the barotropic governor mechanism does not favor the occurrence of the MWS. In contrast, weakened baroclinic energy conversion, buoyancy conversion, and generation of eddy available potential energy by diabatic heating are conducive to the occurrence of the MWS. In addition, Ural blocking in the upstream region of the MNPST may be another candidate mechanism associated with the MWS.     

旧石器时期以来新疆文化遗址分布特征及驱动因素

运用最近邻指数和耦合分析方法,研究了旧石器时期至近现代新疆432处文化遗址时空分布特征及驱动因素。结果表明：（1）新疆文化遗址属于聚集分布模式,集中分布在以12个聚集区为主的丝绸之路南道、中道、北道和塔城-阿勒泰地区4个带。中道和北道的遗址数量约占总量的80.11%。（2）新疆文化遗址可划分为旧石器-商朝、西周-秦朝、汉代-南北朝、隋唐-五代、宋元明、清朝-近现代6个时期,不同时期遗址分布重心经历了塔城-阿勒泰→丝绸之路南道和中道→丝绸之路中道和北道→丝绸之路中道的演变。（3）文化遗址的格局演化与历史时期新疆自然和人文因素等有很好的耦合关系,文化遗址的快速发展期（如西汉、隋唐）与气候的相对凉湿期、中原政权的强盛、屯垦的高潮期、丝绸之路的繁荣期相对应。（4）文化遗址空间分布主要受控于自然因素,而时间变迁更多的是受人文因素的影响。早期自然因素的影响大,而后期人文力量起主导作用,是新疆文化遗址变迁与自然和人文耦合关系的总规律。