滇中地区夏季城市热岛效应的数值模拟研究

为了探究滇中地区不同城市化程度和湖泊下垫面对城市热岛效应的影响,利用中尺度气象模式WRF(the weather research and forecasting model)对昆明等城市的夏季城市热岛效应进行模拟研究。结果显示,夏季夜间,昆明等城市的热岛现象具有明显的下游效应,城市的扩张使得城市热岛下游效应的影响范围扩大,但热岛的强度不会明显地增强。城市的存在会增加地表的粗糙度,使得夜间的近地面风速减小。在白天,湖泊和城市下垫面主要通过改变局地的热力差异影响近地面的风速,城市的存在会加强湖泊与陆地间的热力差异,促进湖陆风环流,进而加大近地面的风速。城市的存在还会减少下垫面对低层水汽的供应,但城市面积的增加对低层水汽的影响相对较小。清晨,城市地区表现为湿岛(湿度较周边地区略大),这与城市地区的近地面辐合流场有关;而在其他时段,城市地区多为干岛(湿度比周边地区低),且干岛现象也存在下游效应。     

基于电池储能和可控负荷的孤岛型海岛微电网频率协调控制策略

针对以风电和波浪能发电为主电源的孤岛型海岛微电网,提出一种基于电池储能和可控负荷的孤岛型海岛微电网频率协调控制策略。储能元件采用改进的下垂控制实现类似于电力系统一次调频的有差调频,根据其荷电状态及最大充放电功率,动态调整下垂控制运行点以及下垂控制系数,既能将微网频率偏差控制在合理范围内,又能防止电池储能系统过充过放;利用海水淡化负荷的可控性,将频率偏差引入其转速控制环,实现类似于电力系统二次调频的无差调频。在Matlab/Simulink下搭建了孤岛型海岛微电网的仿真模型,并对不同运行场景进行了仿真验证。结果表明,基于电池储能和可控负荷的孤岛型海岛微电网频率协调控制策略可以有效地分配系统功率差额,维持海岛微电网的频率稳定。     

Phylogeography of the Eurasian red squirrel (Sciurus vulgaris orientis) on the boreal island of Hokkaido,Japan

To test postglacial population expansion in small arboreal mammals dependent on boreal and subboreal forests, we used complete mitochondrial cytochrome b gene sequences (1140 bases) to investigate the phylogeography of the Eurasian red squirrel (Sciurus vulgaris orientis) on the Hokkaido Island of Japan. This subspecies is common in the boreal and subboreal forests of Hokkaido. We examined 61 specimens from 27 localities in Hokkaido. Phylogenetic relationships among 29 haplotypes found in the Hokkaido populations were not associated with geographic distribution of sampling localities. There were four mitochondrial DNA phylogroups. Phylogeographic analyses support sudden expansion of S. vulgaris orientis from restricted refugium in the southern part of Hokkaido during the last glacial period. The phylogeographic structure of this subspecies directly reflects the boreal and subboreal forest dynamics occurring in Hokkaido.     

Preparation and optical properties of waterborne acrylic-based cool white coatings

Cool coatings （solar reflective coatings） possess a high total solar reflectance and a high thermal emittance, and they have potential applications in building surfaces, pavements, and oil tanks. By decreasing the accumulation of heat, these coatings can reduce the urban heat island effect to increase thermal comfort and to decrease energy consumption in hot zones. In this work, a cool white coating based on waterborne acrylic was prepared. The reflectance and thermal emittance were measured using an ultraviolet- visible-near-infrared spectrophotometer and the steady- state calorimetric technique, respectively. The cool coating possessed a total solar reflectance of 0.887 and a thermal emittance of 0.85. The linear fitting results indicated that the thickness of the dry film is an important factor that affects the reflectance and that the physical limit of total solar reflectance in practical cool coatings is 0.91. A homemade device developed according to military specification MIL-E-46096C was used to measure insulation temperature differences, and an insulation temperature difference of 29 ℃ was obtained. The above results demonstrated that the cool coating can be applied to buildings.     

波纹型通道中粒子运动的非线性现象研究

波纹型通道中粒子运动的相空间轨道取决于波纹型通道的形状,这表明非线性过程动力学行为对初始条件的敏感依赖性。     

露天采煤对雨量影响的调查分析

通过亚洲最大的露天煤矿——平朔安太堡矿10年来的降雨量与临近朔城镇与平鲁区的降雨量分析比较后,证实露天采煤并没有影响到大气降雨,也就没有人们想象中的露天采煤引发的热岛效应现象。     

Experimental Study of Turbulent Wake Behind a Sine Shaped Island in a Shallow-Water Layer

IntroductionThe flow around bluff bodies has been studiedtheoretically,experimentally and numerically formany years[13 ] .However,most research has notconsidered the influence of bed friction on theflow.In coastal and estuarial regions,large- scaleeddies …     

城市热岛效应研究进展

随着城市化的加快,城市热岛会越来越严重.搜集、归纳、整理了国内外大量关于城市热岛的相关文献,给出了城市热岛的形成原因,介绍了其主要的研究方法:气象资料分析法、遥感监测法、数值模拟法的应用及优缺点,总结了城市热岛的时间、空间变化特征及规律,探讨了城市热岛的减缓对策,较系统地反映了目前国内外城市热岛研究的基本情况.最后,对我国城市热岛未来的研究方向进行了展望.     

工业以太环网在煤矿中的应用

针对阐述煤炭企业综合自动化的现状和存在的问题,介绍工业以太环网的组成、性能和特点,提出煤炭企业综合自动化系统的一般构成形式。通过调查煤炭企业的应用现状,找出影响综合自动化使用效果的关键问题和原因。煤炭企业综合自动化的内容较多,通用性又较差,所以要想在煤炭企业建设一套高效、稳定、简洁的综合自动化系统,必须遵循自上而下的实施原则,即在各个子系统的设计、选型和购置上就必须为综合自动化系统做好准备。如果遵循了自上而下的实施方法,可以加快系统集成的进度,消除信息孤岛,缩短建设周期,降低建设成本。