一种土工合成材料加筋土界面拉拔行为分析∗

为研究试验过程中不同位置的筋土界面拉拔行为,以补充试验测量的不足,提出了一个能够预测筋材任意位置拉力和位移的界面拉拔公式,并给出了其具体的应用和分析步骤。首先预测给定筋材长度的最大峰值拉力,然后在最大峰值拉力范围内预测给定峰值拉力的筋材有效长度,其次确定界面摩擦系数大小,最后预测沿筋材任意位置的位移变化关系。同时,对界面拉拔公式进行了参数影响分析,并将界面拉拔公式预测结果与试验结果进行对比。研究结果表明:界面摩擦系数可以间接验证界面拉拔公式的准确性,对拉拔试验结果提供一致性解释。界面拉拔公式的预测结果与拉拔试验结果吻合良好,表明了分析模型的合理性。研究成果对分析和完善筋土界面特性具有重要意义。     

HTPB推进剂老化性能湿热影响分析

目的 掌握HTPB推进剂老化过程中,温度和湿度对其力学性能的影响及贡献程度.方法 对HTPB推进剂进行不同湿热条件下的加速老化试验,并测量不同老化时间推进剂的质量损失分数和力学性能,结合推进剂在温度和湿度下的作用机理,对质量损失分数随老化时间的变化规律进行分析,以最大拉伸强度作为性能指标,对HTPB推进剂湿热老化过程进行湿热双因素方差分析.结果 湿度对HTPB推进剂质量损失分数的影响起主导作用,在75％～85％有一个湿度拐点值,大于或小于这个拐点值,推进剂遵循不同的质量损失分数变化规律.温度和湿度对推进剂最大抗拉强度方差分析的F值均大于其临界值,影响显著.相比而言,湿度的影响更加显著,整个老化过程中,温度和湿度的影响作用表现出先增加、后下降的趋势.温湿交互作用在试验前期和后期对推进剂的影响不显著,而在试验中期较为显著,同样呈现出先增大、后减小的规律.结论 湿度对推进剂最大拉伸强度影响的贡献率最大,温度次之,交互作用最小.从时间轴上看,湿度的贡献率表现为单调递增趋势,温度为单调递减趋势,交互作用呈现抛物线趋势.     

Wrestling with the complexity of evaluation for organizations at the boundary of science,policy, and practice

Boundary organizations are situated between science, policy, and practice and have a goal of supporting communication and collaboration among these sectors. They have been promoted as a way to improve the effectiveness of conservation efforts by building stronger relationships between scientists, policy makers, industry, and practitioners (Cook et al. 2013). Although their promise has been discussed in theory, the work of and expectations for boundary organizations are less defined in practice. Biodiversity conservation is characterized by complexity, uncertainty, dissent, and tight budgets, so boundary organizations face the challenging task of demonstrating their value to diverse stakeholders. We examined the challenges boundary organizations face when seeking to evaluate their work and thus aimed to encourage more productive conversations about evaluation of boundary organizations and their projects. Although no off‐the‐shelf solution is available for a given boundary organization, we identified 4 principles that will support effective evaluation for boundary organizations: engage diverse stakeholders, support learning and reflection, assess contribution to change, and align evaluation with assumption and values.     

Resolving future fire management conflicts using multicriteria decision making

Management strategies to reduce the risks to human life and property from wildfire commonly involve burning native vegetation. However, planned burning can conflict with other societal objectives such as human health and biodiversity conservation. These conflicts are likely to intensify as fire regimes change under future climates and as growing human populations encroach farther into fire‐prone ecosystems. Decisions about managing fire risks are therefore complex and warrant more sophisticated approaches than are typically used. We applied a multicriteria decision making approach (MCDA) with the potential to improve fire management outcomes to the case of a highly populated, biodiverse, and flammable wildland–urban interface. We considered the effects of 22 planned burning options on 8 objectives: house protection, maximizing water quality, minimizing carbon emissions and impacts on human health, and minimizing declines of 5 distinct species types. The MCDA identified a small number of management options (burning forest adjacent to houses) that performed well for most objectives, but not for one species type (arboreal mammal) or for water quality. Although MCDA made the conflict between objectives explicit, resolution of the problem depended on the weighting assigned to each objective. Additive weighting of criteria traded off the arboreal mammal and water quality objectives for other objectives. Multiplicative weighting identified scenarios that avoided poor outcomes for any objective, which is important for avoiding potentially irreversible biodiversity losses. To distinguish reliably among management options, future work should focus on reducing uncertainty in outcomes across a range of objectives. Considering management actions that have more predictable outcomes than landscape fuel management will be important. We found that, where data were adequate, an MCDA can support decision making in the complex and often conflicted area of fire management.     

巢湖生态系统中微量有机污染物的研究进展

本文综述了目前巢湖生态系统中微量有机污染物研究的主要进展。巢湖微量有机污染物研究起步较晚,但发展较快。目前已研究的微量有机污染物包括有机氯农药、多氯联苯、多环芳烃、多溴联苯醚、邻苯二甲酸酯、全氟烷基酸类物质、四溴双酚A、抗生素和有机磷农药。研究内容主要包括水、大气、降尘、沉积物、悬浮物、水生生物等多介质分布、来源解析、跨界面迁移、归趋模拟与风险评估等方面。期望本文的综述,可以为巢湖微量有机污染物风险管理和水质改善提供重要决策支撑,对于在其他湖泊开展此类研究有所裨益。     

Completion of recommended WUI fire mitigation measures within urban households in Edmonton,Canada

The purpose of this study was to examine completion of recommended wildland—urban interface (WUI) fire mitigation measures by residents adjacent to the heavily vegetated North Saskatchewan river valley and ravine system in the City of Edmonton, Alberta. A mail survey was distributed to a random sample of households adjacent to this natural area. Almost all homeowners were found to be completing some recommended mitigation measures and in many cases were willing to complete most but not all of the measures that they had not yet completed, despite mixed motivations to act. Perceived responsibility for reducing risks, social bonds, beliefs that emergency services would protect homeowners' property in the event of a fire, and perceptions of the effectiveness of recommended mitigation measures, were not significantly related to completion of a higher average number of recommended mitigation measures. Importantly, most mitigation measures were completed for reasons other than WUI fire mitigation. The implications of these results and recommendations for emergency managers and communicators are discussed.     

太湖水-沉积物界面磷、pH及碱性磷酸酶的时空特征及相关性

于2011年3、6和9月通过对太湖不同营养化湖区的5个标准采样位点进行采样分析,探讨了界面沉积物间隙水和上覆水中磷含量、pH及碱性磷酸酶活性的时空分布特征及相关性。结果表明,上覆水及沉积物间隙水中的总磷（TP）、可溶性正磷酸盐（SAP）、pH及碱性磷酸酶（ALP）活性均表现出明显的空间异质性和季节变化趋势。间隙水总磷（PW-TP）、间隙水可溶性正磷酸盐（PW-SAP）高于上覆水,分别最高高出0．082、0．042mg·L-1;上覆水pH值高于间隙水pH值,最高高出O．35个单位;间隙水中碱性磷酸酶（PW-ALP）活性高于上覆水中碱性磷酸酶（W-ALP）活性,最高高出13．244μg·mL·h-1。TP、SAP、pH及ALP活性在3、6、9月份中均以16#样品最高,其中6月份16#样品PW-TP、PW-SAP、上覆水pH及PW-ALP活性分别O．527、0．132、7．46和61．090μg·mL·h-1。参数相关性分析结果表明,W-TP与W-SAP、W-pH显著相关。W-SAP与PW-TP、PW-SAP、W-ALP、PW-ALP均显著相关。PW-TP与PW-pH显著相关性,与PW-ALP活性存在一定的相关性,但不显著。PW-SAP与PW-ALP显著相关。     

采空区精确建模信息系统实体模型交互接口开发

随着矿业的快速发展,Surpac,Dimine,3DMine等三维矿业软件在矿业领域得到了广泛的应用。为进一步完善自主研发的采空区激光扫描三维精确建模信息系统功能,在解析stl,dxf及dtm格式文件的数据结构及其三维实体数据存储规律的基础上,成功地开发了基于上述三种实体模型存储文件格式的采空区三维实体模型交互接口,实现了信息系统与目前主流三维矿业软件之间三维实体模型的交互。实用表明,所开发的接口能有效实现信息系统与其他三维矿业软件之间采空区三维模型的交互与共享,进一步完善了信息系统的模型数据输入输出功能,提高了其应用价值。     

NM93C46EEPROM及其在M68HC05单片机上的应用

本文介绍用Ｍ６８ＨＣ０５单片机对ＮＭ９３Ｃ４６串行ＥＥＰＲＯＭ进行操作的软硬件技术及读写程序设计的三种方法     

EXPANSION OF SALT-WATER ZONE DUE TO WELL DISCHARGE1

ABSTRACT: In coastal confined aquifers, the extent of the salt-water wedge due to natural ground-water flow can be determined by available methods. If water is pumped by a discharge well, the quality of the water depends upon the rate and duration of pumping as well as the location of the well. A study has been made to find the extent of the progress of salt-water intrusion due to the operation of one discharge well taking into account various conditions of aquifer properties, pump capacities, natural flows, time effects, and well locations. Dimension-less solutions for specific conditions have been obtained by means of a simple computer program. Range of most common conditions is discussed. One of the main findings of this study was that salt water may be pumped out of a well even if it is located in an initially totally fresh-water zone beyond the natural salt/fresh-water interface.