某机载雷达多自由度振动试验控制方法比较

根据机载雷达实测振动数据,在三轴振动台上,采用不同振动控制方法,对机载雷达单元进行了多自由度振动试验。比较了雷达单元在不同振动控制方法下的安装点响应与参考谱的偏差。试验结果表明:相比于方阵控制,长方阵控制中的坐标变换控制(Input/Output控制)方法在进行多自由度振动试验时,可实现真正意义上的平均控制,振动的传递更为均匀。     

场地地震反应分析研究现状及展望∗

场地条件对结构震害的影响已成公认的事实,如何定量的进行场地地震反应分析成为地震工程学中亟待解决的问题之一,而在场地地震反应分析中确定地震动输入至关重要。针对场地条件和地震动输入对场地地震反应的具体影响、场地地震反应分析方法等方面的研究现状进行了系统总结。已有研究表明,场地条件和地震动输入对场地地震反应分析结果有显著影响。但目前仍存在的问题有:在冻土区进行场地地震反应分析时未充分考虑冻土层的影响效应;缺乏合理的地震动模型来准确描述实际地震动;尚未明确地震波入射角度对场地地震反应的影响规律;目前广泛使用的等效线性化方法不能完全反应土体在地震动作用下的真实运动状态而使其计算结果不尽合理。结合以上问题对还需进一步研究的内容进行了展望,为场地地震反应分析未来的研究工作提供参考。     

外置双U型静钻根植工法能源桩换热性能研究∗

为探究外置双U型静钻根植工法能源桩换热性能,通过现场热响应试验,利用热源理论初步分析其岩土综合导热系数,建立三维传热数值模型并进行验证。利用三维传热数值模型分析换热管间距及其导热系数、换热液流速和桩周水泥土导热系数等因素对该新型桩换热性能的影响。分析结果表明,试桩区域岩土综合导热系数为1.64W(m·K)-1。提高换热管间距、换热管导热系数、换热液流速和桩周水泥土导热系数均能提高能源桩的换热性能,但当换热管间距大于0.25 m,换热液流速达到紊流态,换热管和桩周水泥土导热系数高于岩土综合导热系数后,提高上述参数对能源桩换热性能的提高贡献不大。     

Dynamic response characteristics and structural optimization of isolation seal under the impact of gas explosion

Either in the chemical process plants or in the underground infrastructures, the isolation seal is regularly used to separate the working sections and inactive sections, or to isolate the possible explosion sites in order to avoid any domino effects. Due to differences in accumulation space or ignition point locations, pressure on the seal can vary when an explosion occurs. Thus, the safety and reliability of seals are crucial to maintaining safety in process industry. This paper focuses on seals constructed with concrete and loess materials, and examines the dynamic response characteristics of the gas explosion wave on the seal through sample experiments and numerical simulation metods. The study proposes an optimized design for the explosion-proof structure of the wedge-shaped and spherical seal, which can provide a technical basis for the explosion-proof and anti-explosion measures of various sealed walls. These research findings can also serve as a basis for improving the construction quality of seals.     

活性氧化铝吸附法在河道砷污染应急处置中的应用

以江苏省邳苍分洪道砷污染事件为例,介绍了活性氧化铝吸附法在大型砷污染河流中的应急处置,对污染的背景、治污处理工艺水平、处理方案和过程进行探讨。结果表明,该方法对大水量、中低浓度的水体砷污染治理有一定的效果,为今后此类事件的应急处置提供了借鉴。     

Cyclone disaster vulnerability and response experiences in coastal Bangladesh

For generations, cyclones and tidal surges have frequently devastated lives and property in coastal and island Bangladesh. This study explores vulnerability to cyclone hazards using first‐hand coping recollections from prior to, during and after these events. Qualitative field data suggest that, beyond extreme cyclone forces, localised vulnerability is defined in terms of response processes, infrastructure, socially uneven exposure, settlement development patterns, and livelihoods. Prior to cyclones, religious activities increase and people try to save food and valuable possessions. Those in dispersed settlements who fail to reach cyclone shelters take refuge in thatched‐roof houses and big‐branch trees. However, women and children are affected more despite the modification of traditional hierarchies during cyclone periods. Instinctive survival strategies and intra‐community cooperation improve coping post cyclone. This study recommends that disaster reduction programmes encourage cyclone mitigation while being aware of localised realities, endogenous risk analyses, and coping and adaptation of affected communities (as active survivors rather than helpless victims).     

Archetypes of famine and response

Famines have long been characterised by rapidly shifting dynamics: sudden price spirals, sharp increases in mortality, the media frenzy that often accompanies such spikes, the swift scaling up of aid flows, and a subsequent decline in interest. In arguing that these aspects of famine have been largely ignored in recent years due to attention to the famine process', this paper attempts to make these dynamics more explicit by applying systems thinking. It uses standard archetypes of systems thinking to explain six situations—watch, price spiral, aid magnet, media frenzy, overshoot, and peaks—that are present in many famine contexts. It illustrates their application with examples from crises in Ethiopia, Malawi, Niger, and Sudan. The paper contends that the systems approach offers a tool for analysing the larger patterns in famines and for pinpointing the most appropriate responses to them, based on an awareness of the dynamics of the crises.     

经济发达地区城市灾害综合应对能力评价分析——以珠江三角洲城市为例

以我国经济发达的珠江三角洲经济区城市作为研究对象,构建了城市自然灾害综合应对能力评价指标体系,在实证测算研究的基础上,对经济快速发展过程中珠三角城市自然灾害应对能力的时空演变规律、协调度特征等进行了分析和研究,对综合评价城市灾害管理水平具有一定的理论和实践意义。     

地震应急快速触发响应系统的需求分析与总体设计

介绍了中国数字地震观测网络项目应急分项软件"地震应急快速触发响应系统"的需求分析和总体功能设计,并对各子系统的技术实现方案以及软件的数据流程等内容进行了比较详细的说明。     

人体动力特性振动台试验研究

随着社会发展和经济水平的提高,人们对于生产、生活的环境质量要求也不断提升,因而环境振动已越来越多的引起了社会的关注,为了研究环境振动对人体的影响,需要了解人体动力特性和在振动环境下的响应。对20名受试者以站、坐、躺姿进行了水平两向输入白噪声的振动台试验,测得人体头、肩、腹、上肢、下肢五个部位的振动响应,通过对人体各部分振动频率与身高、体重、年龄的关系分析,给出了人体频率分布规律。