考虑拦污栅-坝体相互作用的混凝土重力坝抗震安全性分析

对考虑拦污栅-坝体的动力相互作用的弹性连接和刚性连接的拦污栅-坝体以及不作耦联分析的拦污栅-坝体这三种不同模型结构形式的动力特性和动力响应进行了比较分析。研究发现,拦污栅的不同模型结构形式对大坝的抗震安全性分析有重要影响,考虑拦污栅-坝体的动力相互作用后,坝体损伤开裂的程度明显加大,坝顶的水平位移响应也明显提高。按《规范》规定的对拦污栅和坝体不作耦联分析的抗震计算方法,所得结果对坝体是偏于不安全的,而如考虑拦污栅-坝体之间的弹性连接,所得结果则是偏于安全的。     

Effects of human footprint and biophysical factors on the body-size structure of fished marine species

Marine fisheries in coastal ecosystems in many areas of the world have historically removed large-bodied individuals, potentially impairing ecosystem functioning and the long-term sustainability of fish populations. Reporting on size-based indicators that link to food-web structure can contribute to ecosystem-based management, but the application of these indicators over large (cross-ecosystem) geographical scales has been limited to either fisheries-dependent catch data or diver-based methods restricted to shallow waters (<20 m) that can misrepresent the abundance of large-bodied fished species. We obtained data on the body-size structure of 82 recreationally or commercially targeted marine demersal teleosts from 2904 deployments of baited remote underwater stereo-video (stereo-BRUV). Sampling was at up to 50 m depth and covered approximately 10,000 km of the continental shelf of Australia. Seascape relief, water depth, and human gravity (i.e., a proxy of human impacts) were the strongest predictors of the probability of occurrence of large fishes and the abundance of fishes above the minimum legal size of capture. No-take marine reserves had a positive effect on the abundance of fishes above legal size, although the effect varied across species groups. In contrast, sublegal fishes were best predicted by gradients in sea surface temperature (mean and variance). In areas of low human impact, large fishes were about three times more likely to be encountered and fishes of legal size were approximately five times more abundant. For conspicuous species groups with contrasting habitat, environmental, and biogeographic affinities, abundance of legal-size fishes typically declined as human impact increased. Our large-scale quantitative analyses highlight the combined importance of seascape complexity, regions with low human footprint, and no-take marine reserves in protecting large-bodied fishes across a broad range of species and ecosystem configurations.     

高效反渗透工艺处理电厂废水

采用“机械加速澄清—重力式过滤—离子交换—除碳—高效反渗透” 工艺处理某电厂废水,将反渗透产水作为冷却塔补水。运行结果表明：弱酸阳离子交换器出水碱度≤0.10 mmol/L、硬度≤0.02 mmol/L、浊度≤0.2 NTU,满足高效反渗透对进水水质的要求;高效反渗透产水浊度<0.1 NTU,COD_Mn≤0.08 mg/L,硬度≤1.12 mg/L,碱度≤8.40 mg/L,ρ（总铁）<10 μg/L,ρ（总硅）<0.5 mg/L,电导率<45 μS/cm,出水水质满足回用要求。针对该系统存在的自用水率高、过滤器污堵以及水量不平衡等问题提出了相应的建议。     

江苏沿海地区经济联系及物流要素流量空间特征分析

随着经济一体化的发展,城市间经济联系日益加强,必然引起城市间物流需求联系的增加。借鉴引力模型在经济联系中的应用,分析了江苏沿海地区城市间经济联系强度。结果表明：城市间经济联系的强度随着空间距离的递增而递减;并以区域中心城市为中心,向外呈辐射状圈层构造,呈现3个层次结构;沿海中心城市对经济联系腹地间的竞争更加明显。立足运输地理学网络分析基本原理, 从客流、货流和信息流等流量,流向等空间属性进一步探讨城市间的经济联系特征,江苏沿海地区市际间货流量连云港 南通占主要地位;客流量连云港 南通一线最大;城市间信息传递不畅,信息流量较弱。针对城市间经济联系及物流要素流量的空间特征,提出了加强区域经济合作的策略与建议     

A comparison between superfine magnesium hydroxide powders and commercial dry powders on fire suppression effectiveness

The effectiveness of superfine magnesium hydroxide powders and commercial dry powder in fire suppression were compared in a laboratory-scale, immovable fire suppression apparatus. The investigation focused on their suppression effectiveness under various pressures. It likewise studied the relationship between the powders’ surface structures and their effectiveness on fire suppression. The microcosmic structure of the powders was observed by scanning electron microscope (SEM), while the Thermal Gravity Analysis (TGA) technique was used to analyze the thermal behavior of the superfine magnesium hydroxide powders. By analyzing the results, it could be concluded that the pressure, the particle size, and the microcosmic structure of the powders’ surface mainly decide the capability of the powders to extinguish the fire. Comparing this with commercial dry powders, superfine magnesium hydroxide powders extinguished the fire in less than 10 s.     

Characteristics of sewer biofilms in aerobic rural small diameter gravity sewers

Small diameter gravity sewers(SDGS) are extensively used to collect rural sewage as they are low in cost and quick to construct.However,the characteristics of biofilms in rural SDGS are still not clear.In this study,biofilms characteristics of aerobic rural SDGS were investigated using simulations in a lab under different flow conditions and slopes.Results indic ated that the average thickness of aerobic rural SDGS biofilms was in the range of 350-650 μm,decreasing at locations with variable flo...     

泛长三角地区工业污染重心演变路径及其驱动机制研究

工业污染重心路径演变是制造业转移过程中形成的环境空间响应形式,为探明经济发达的泛长三角地区工业污染重心对制造业转移的响应关系,采用2000~2010年工业污染排放数据,运用重心模型,测算各年份工业废水、废气和固废排放重心坐标,分析工业污染重心转移路径及演变规律,探讨重心演变的驱动机制.结果表明:1泛长三角地区的工业污染重心发生了偏移,其中工业固废偏移距离最大,为180.18 km,而工业废水、废气偏移的方向最大,分别为0.40°、0.17°;2工业污染重心轨迹偏移受多种因素的驱动影响.其中,安徽、江西地区重工业的高速发展加剧了污染重心朝西部偏移;以江苏、上海、浙江为代表的长三角地区产业结构优化与调整在一定程度上缓解了该地区的工业污染,安徽、江西地区高污染产业份额的增加及宽松的宏观区域政策助推了工业污染向西部地区偏移;而大规模的清洁化生产、较强的环境治理力度和完善的环保监测制度在一定程度上减缓了工业污染朝东部地区偏移.     

重庆市农用地整治项目时空分异特征研究

以2002~2013年重庆市农用地整治项目数据为基础,采用数理统计法和重心模型法,对12 a间重庆市农用地整治项目的时空分异特征进行研究。得出以下结论:1重庆市农用地整治项目主要分布在城市发展新区和渝东北生态涵养发展区。项目平均规模受地形影响较大,项目平均投资额与项目区区位条件、地形条件、现代农业发展方向、生态文明建设等因素有关。2项目数量、项目规模及项目投资额的重心移动均在经度和纬度方向呈现波动变化,但基本集中在全市的中部位置,全市农用地整治项目的空间分布具有一定的地域均衡性。项目重心整体呈向东北方向移动的趋势,重心移动的方向和距离受政策因素影响明显。3根据项目数量、项目规模和项目投资额的重心点及其移动轨迹可以将重庆市12 a间农用地整治项目分为起步阶段、发展阶段、完善阶段、成熟阶段四个阶段。最后对重庆市农用地整治政策制定和项目布局提出了相应的政策建议。     

Prenatal diagnosis of Schwartz–Jampel syndrome with early manifestation

A mother who had given birth to a child with Schwartz–Jampel syndrome (SJS) with neonatal manifestations (myotonia, congenital contractures, bowing of femora and tibiae) underwent ultrasonic fetal examination during the 17th and 19th week of her second pregnancy. Moderately decreased fetal motor activity and constant flexion of the fingers were observed at both examinations. In addition, there was mild bowing and shortening of the femora. At birth, the child presented with the characteristic pattern of SJS similar to her older brother. Prenatal ultrasonic diagnosis of Schwartz–Jampel syndrome is possible, at least for the form with neonatal onset of myotonia and contractures.     

Frequency of Iris Depigmentation in Urban Populations of Rana arvalis Frogs

Russian Journal of Ecology -