Biological community including carabids and spiders were investigated in 30 various fields margins and 10 related fields by pitfall trap in Quzhou area of North China Plain.It was concluded that biodiversity index and...Biological community including carabids and spiders were investigated in 30 various fields margins and 10 related fields by pitfall trap in Quzhou area of North China Plain.It was concluded that biodiversity index and numbers of biological groups in field margins are higher than those in the related crop fields.There is a given relationship between the attributes of field margins and biodiversity.The control of structure and vegetation in field margins would be the possible way to protect natural enemy such as carabides and spiders.展开更多
深度探索用户负荷可调节潜力是国家电力市场精细化发展的迫切需求。为有效感知电力用户负荷综合响应潜力,提出一种模糊粗糙环境下的混合评估模型。首先,从经济性、用户特性、负荷特性、信息特性等4个维度构建负荷响应潜力指标体系;其次...深度探索用户负荷可调节潜力是国家电力市场精细化发展的迫切需求。为有效感知电力用户负荷综合响应潜力,提出一种模糊粗糙环境下的混合评估模型。首先,从经济性、用户特性、负荷特性、信息特性等4个维度构建负荷响应潜力指标体系;其次,充分考虑评估中个体判断的模糊性和群体偏好的多样性,采用模糊粗糙数对个体语义评估信息进行处理和集结;然后,将模糊粗糙熵权法和逐步加权评估比率分析法(step-wise weight assessment ratio analysis,SWARA)相结合确定指标综合权重,并采用基于模糊粗糙数的改进多属性边界逼近区域比较法(multi-attributive border approximation area comparison,MABAC)计算电力用户针对属性函数的负荷响应潜力综合评估值,从而获取潜力排序结果;最后,以多个行业的电力用户负荷综合响应潜力评估为例,验证所提模型的有效性。展开更多
Boundary-layer wind tunnel provides a unique platform to reproduce urban, suburban and rural atmospheric boundary layer （ABL） by using roughness devices such as vortex generators, floor roughness, barrier wails, and...Boundary-layer wind tunnel provides a unique platform to reproduce urban, suburban and rural atmospheric boundary layer （ABL） by using roughness devices such as vortex generators, floor roughness, barrier wails, and slots in the extended test-section floor in the contraction cone. Each passive device impacts wind properties in a certain way. In this study, influence of various passive devices on wind properties has been investigated. Experi- ments using eighteen different configurations of the passive devices have been carried out to simulate urban, sub-urban, and rural climate conditions in a boundary-layer wind tunnel. The effect of each configuration on the wind characteristics is presented. It was found that higher barrier height and more number of roughness elements on the floor, generated higher turbulence and therefore higher model scale factors were obtained. However, in- creased slot width in the extended test-section floor in the contraction cone of the wind tunnel seemed to have a little effect on wind characteristics.展开更多
文摘Biological community including carabids and spiders were investigated in 30 various fields margins and 10 related fields by pitfall trap in Quzhou area of North China Plain.It was concluded that biodiversity index and numbers of biological groups in field margins are higher than those in the related crop fields.There is a given relationship between the attributes of field margins and biodiversity.The control of structure and vegetation in field margins would be the possible way to protect natural enemy such as carabides and spiders.
文摘深度探索用户负荷可调节潜力是国家电力市场精细化发展的迫切需求。为有效感知电力用户负荷综合响应潜力,提出一种模糊粗糙环境下的混合评估模型。首先,从经济性、用户特性、负荷特性、信息特性等4个维度构建负荷响应潜力指标体系;其次,充分考虑评估中个体判断的模糊性和群体偏好的多样性,采用模糊粗糙数对个体语义评估信息进行处理和集结;然后,将模糊粗糙熵权法和逐步加权评估比率分析法(step-wise weight assessment ratio analysis,SWARA)相结合确定指标综合权重,并采用基于模糊粗糙数的改进多属性边界逼近区域比较法(multi-attributive border approximation area comparison,MABAC)计算电力用户针对属性函数的负荷响应潜力综合评估值,从而获取潜力排序结果;最后,以多个行业的电力用户负荷综合响应潜力评估为例,验证所提模型的有效性。
文摘Boundary-layer wind tunnel provides a unique platform to reproduce urban, suburban and rural atmospheric boundary layer （ABL） by using roughness devices such as vortex generators, floor roughness, barrier wails, and slots in the extended test-section floor in the contraction cone. Each passive device impacts wind properties in a certain way. In this study, influence of various passive devices on wind properties has been investigated. Experi- ments using eighteen different configurations of the passive devices have been carried out to simulate urban, sub-urban, and rural climate conditions in a boundary-layer wind tunnel. The effect of each configuration on the wind characteristics is presented. It was found that higher barrier height and more number of roughness elements on the floor, generated higher turbulence and therefore higher model scale factors were obtained. However, in- creased slot width in the extended test-section floor in the contraction cone of the wind tunnel seemed to have a little effect on wind characteristics.
