国家陆地搜救基地训练设施设计原则及构成分析

＂科学施救＂是公安消防部队进行应急救援任务的核心理念,而专业化、模拟化训练则是实现＂科学施救＂的必要手段。如何构建高仿真、动态化的模拟训练设施,进一步提高公安消防部队应急救援水平,已成为公安消防部队面临的一个重要课题。文章对部分发达国家应急救援训练设施建设情况进行了分析,从实战救援的角度,提出了国家陆地搜寻与救护基地模拟训练设施的设计原则,并结合实战需要,给出了模拟训练设施的基本构成和功能介绍,供各地在规划和建设模拟训练设施时参考、借鉴。     

Electrochemical machining characteristics and resulting surface quality of the nickel-base single-crystalline material LEK94

Nickel-base single-crystalline materials such as LEK94 possess excellent thermo-mechanical properties at high temperatures combined with low density compared to similar single-crystalline materials used in aero engines. Since the components of aero engines have to fulfil demanding safety standards, the machining of the material used for these components must result in a high geometrical accuracy in addition to a high surface quality. These requirements can be achieved by electrochemical and precise electrochemical machining (ECM/PECM). In order to identify proper machining parameters for PECM the electrochemical characteristics dependent on the microstructure and the chemical homogeneity of LEK94 are investigated in this contribution. The current density was found to be the major machining parameter affecting the surface quality of LEK94. It depends on the size of the machining-gap, the applied voltage and the electrical conductivity of the electrolyte used. Low current densities yield inhomogeneous electrochemical dissolution of different microstructural areas of the material and lead to rough surfaces. High surface qualities can be achieved by employing homogenous electrochemical dissolution, which can be undertaken by high current densities. Furthermore, a special electrode was developed for the improvement of the quality of side-gap machined surfaces.     

关于我国跨部门环境管理协调机制的构建研究

环境资源作为公共资源,由于其自身属性和使用方式的多样化决定了环境保护需要多个部门的配合和合作。由于立法、历史等原因,条块分割的环境管理体制下各部门之间管理机构重叠、职能交叉、权限不清,缺乏有效的跨部门环境管理协调机制。根据国外环境管理的先进经验,政府各部门间的有效协调,需要在完备法律体系的基础上,构建一个高规格、跨部门的环境管理协调机构,并采用多种形式的协调手段,建立健全部门协调管理体系;同时加强各部门间的合作和交流,建立起法制化、规范化的行政协助制度,并通过资源整合机制,充分发挥各种社会力量的作用,有助于环境政策的优化以及提高政府各相关部门执法的公正性和有效性。     

混合菌对表层沉积物中重金属形态及生物有效性的影响

采用改进的Tessier连续萃取法对表层沉积物中重金属(内源体系:Fe、Mn、Cu、Zn和Pb;外源体系:掺杂Cu、Zn和Pb后的Fe、Mn、Cu、Zn和Pb)一定时间(45d)内的形态分布进行分析,探讨了混合菌对体系中重金属形态及生物有效性的影响。混合菌的加入促进了沉积物中Fe向可交换态、碳酸盐结合态的转变,Fe的生物有效性显著提高;混合菌的掺杂导致了Mn向稳定态的移动,体系中Mn的各形态除可交换态含量均有所提高,且混合菌可以提高Mn的生物有效性;混合菌的存在增加了内源体系中Zn的铁锰氧化态稳定性,外源体系中混合菌的添加促进了其活化作用,与混合菌前33d降低金属有效性相矛盾;混合菌加入使内源体系中Pb残渣态和外源体系中有机质结合态升高,与混合菌加大Pb的有效性不吻合;混合菌可导致内源体系Cu的铁锰氧化物含量增加和铁锰氧化物态下降、Cu的生物有效性提高,而外源体系中前Cu的碳酸盐结合态上升,混合菌降低了Cu生物有效性。     

Sensitivity of protective barrier performance to changes in rainfall rate

Single- or multi-layered surface barriers are used for protecting the underlying hazardous or radioactive waste storage facility and for reducing the risk of dispersion of contaminants to the ground water. To assess the effect of variations in net rainfall rate (total rainfall minus evapotranspiration) on the hydraulic response of a multi-layered barrier, a series of flow simulations were performed. Water fluxes in different layers of the barrier were numerically calculated for three net rainfall rates, i.e. 0.0255, 0.0742, and 0.141 cm/day. These rates correspond to dry, average, and wet climatological conditions in Belgium. Results show that for dry conditions, almost 45% of the water infiltrating the top of the barrier is laterally evacuated. When the net rainfall rate increases from 0.0255 to 0.0742 cm/day, more water is being laterally diverted, and only 22% of the applied rainfall percolates through the barrier. If the rainfall rate is increased from 0.0255 to 0.141 cm/day, the percolation becomes 14% of the applied rainfall. This indicates that fluxes leaving the bottom of the repository increase only slightly, although the rainfall rate for wet conditions is approximately 5 times larger than for dry conditions. Under dry conditions a slightly negative pressure develops in the bottom of the low-permeability clay layer. However, this desaturation does not affect the integrity of the clay.     

SCR钒基催化剂吸附氨和水的密度泛函研究

利用密度泛函理论和原子簇模型,对NH3和H2O分子在选择性催化还原(SCR)脱硝催化剂表面不同吸附位上的吸附进行了研究.结果表明:NH3能吸附在V2O5表面的Lewis和Bronsted酸位,但在后者吸附位上更稳定.当V2O5以多聚物结构存在时,NH3能与O(1)H生成稳定的NH4 ,该物质在SCR反应中起着关键作用,吸附能为-128 kJ·mol-1;同时水也可与该吸附位形成稳定构型,吸附能为-97 kJ·mol-1.在V2O5表面,水与NH3的吸附能相当,两者发生竞争吸附,从而在一定程度上对SCR脱硝反应产生抑制作用.     

Simulating dynamics of managed monsoon evergreen broad-leaved forest in south China

The forest succession model FORDYN is developed based on TREEDEV model. TREEDEV is a process-based tree growth model, that calculates tree growth based on carbon and nitrogen balance, and is calculated using on the photo-production of leaves, respiration, nitrogen content of all organisms and that in soil, and other losses due to respiration, litter and renewal of stems, branches, leaves and roots. In the FORDYN model succession is divided into three phases called early, middle and late succession, and the transition between these three succession phases is distinguished by a difference in leaf area index. As a verification of the model we used the characteristics and available data of a monsoon evergreen broad-leaved forest in Dinghushan Biosphere Reserve (DHS-BR). The model was validated with natural forest data. In addition, a sensitivity analysis was performed in which 30 independent variables were varied and analyzed in connection with their influence on 16 dependent variables describing forest conditions. The simulation results describe the changes in total biomass, carbon and nitrogen change in plant–litter–soil system of an undisturbed monsoon evergreen broad-leaved forest during succession. We compared these findings with simulation in which different logging management strategies were used. The results show that having a longer logging cycle, delaying the first logging time and a smaller logging fraction the scenario can contribute to a sustainable forest development, while still having a positive economic yield.     

土壤动物在污染评价中的作用、现行指标及胁迫环境下的耐受性

土壤污染的动物评价方法需要改进与创新.论文从土壤动物功能群的生物学特性、生活习性及其在土壤养分循环中的作用等方面,综述了土壤动物在土壤污染评价中的应用;介绍了目前国际上通用的土壤动物评价指标和使用方法,包括种群特征、群落结构和生态区域模型;联系土壤污染状况和趋势,阐述了土壤动物对污染胁迫的耐受性及其对现行土壤污染评价方法的影响,并在可塑型适应和组成型适应上探讨了土壤动物耐受性产生的遗传学机理与生物学指标.     

太子河流域大型底栖动物功能摄食类群与环境要素的关系

根据2009年8月太子河流域野外调查数据,分析了大型底栖动物的5个主要功能摄食类群的组成,包括直接收集者(gc)、捕食者(pr)、过滤收集者(fc)、撕食者(sh)和刮食者(sc),研究结果表明,太子河大型底栖动物以gc为主,占底栖动物总个体数的85.5%,其次为fc、sh、sc和pr,分别占总个体数的6.0%、3.0%、5.5%和0.0%,并且gc对人为干扰的耐受性较强,pr、sh、sc对环境条件变化较为敏感.通过5种功能摄食类群的相对丰度与水质因子相关分析,分析结果表明,海拔、水温、电导率、总氮、硝态氮、亚硝态氮与gc相关性较大;而海拔、水温、电导率、pH值、总氮、亚硝态氮与pr、sc和sh相关性较大.将土地利用格局与5种功能摄食类群进行逐步回归分析,结果表明,农田和河滩对gc影响显著;而农田对pr、sc和sh影响显著.     

大肠杆菌与水体中U(Ⅵ)的作用行为和产物研究

通过批次吸附实验及介观和谱学等表征方法,研究了大肠杆菌(E.coli)粉末对水体中U(Ⅵ)的富集行为和吸附模型,并对其作用产物进行了详细分析.结果表明:大肠杆菌对初始浓度为50mg/L U(Ⅵ)溶液(pH＝5)的吸附容量可达到276.89mg/g.Langmuir等温模型和准二级动力学方程能较好的描述其吸附过程. FTIR、SEM-EDS、XRD分析结果表明:在与水体中U(VI)作用后,大肠杆菌表面检测出UO₂²⁺的红外特征峰(876.16cm^-1)和U的能谱吸收峰(结合能=2.4~4.4keV).UO₂²⁺主要与菌体表面的烷基、氨基、羧基、分子间氢键发生作用,重点与PO₂-、P(OH)₂、PO₄^3-以及PO₃^-等含P基团进行络合配位,最终产物以CaU(PO₄)₂、Ca(UO₂)₂(PO₄)₂·xH₂O、NaUO₂(PO₃)₃等铀的磷酸盐形式存在.