环境物探技术在岩溶勘察中的应用及其效果

将高密度电阻率法及工程地震映像法两种环境物探技术同时应用于实际的地质灾害(岩溶)勘察中,结果表明:对于岩溶这样的地质灾害,单一环境物探技术虽然能清楚反映其埋深、规模和发育情况,但各有缺陷。而多种环境物探技术的综合使用,相互补充,将能大大提高岩溶勘察的准确性,提高勘察效果和效率。     

从印度洋地震海啸看中国的巨灾风险

2004年12月26日印度洋海啸给沿岸国家造成了严重灾难,其主要原因是缺乏必要的防范。中国历史上巨灾频发,今后仍存在比较严重的巨灾威胁。预测我国有11个巨灾高风险区,巨灾种类主要为特大洪水、大地震、强台风和特大风暴潮以及大区域持续性严重干旱。建立巨灾防御体系是今后我国减灾工作的重心。     

古代黄河中游的环境变化和灾害——对都城迁移发展的影响

都城的选址、建设和迁移发展必须以环境资源为基础。我国古代的国家都城在黄河中游反复迁移，以至最后东迁南迁。在这个过程中，环境变迁和灾害一直是重要的驱动因素之一。通过统计分析历史时期洪涝和干旱灾害，以及气候水文变化资料，结合古都所在地的环境资源条件分析讨论，揭示了黄河中游环境变化和灾害对都城迁移发展的影响。都城在长安与洛阳之间的反复迁移，以及后来的东移开封，和南移到长江下游平原，环境的变迁是重要的驱动力之一。     

航空安全风险管理模式探讨

航空安全需要动态管理,因此构建并实施基于问题管理的航空安全风险管理模式就非常有意义。本文探讨了航空公司、机场和空管的安全管理工作如何围绕航空安全问题为中心进行制度、组织、日常管理构建,注重问题的识别、分析和解决,切实有效的地解决安全问题。实施安全问题管理变专职安全管理为全员安全管理;变间接安全管理为直接安全管理;变滞后安全管理为超前安全管理;变僵化安全管理为创新安全管理;变被动安全管理为主动安全管理;变模糊安全管理为务实安全管理。无疑这种管理模式均适合民航三大主体的安全管理需求。     

航空安全文化的研究进展

结合国内外对航空安全文化定量和定性的研究结果,定义了航空安全文化,并阐述航空安全文化的内涵,介绍国内外航空安全文化研究的进展情况,指出了国内外航空安全文化研究的差距,进而给出我国航空安全文化的研究方向。目的在于使以后的研究越来越关注实证角度,为从人为因素角度加强航空安全提供可靠、可信的数据支持,提高飞行绩效,创造安全飞行周期新记录,最终提高航空公司的经济及社会效益。     

天然气钻井井口安全距离研究分析

分析天然气钻井井场可能发生的事故类型及事故的破坏程度,选择适合的事故后果模型,对天然气井井喷失控后可能发生的蒸气云爆炸及硫化氢扩散的后果进行量化分析,根据超压-冲量准则、热剂量准则和硫化氢扩散行为规律,计算出爆炸波、爆炸火球及硫化氢扩散的危害范围。笔者建立了天然气钻井井口安全距离的计算模型,并提出一种确定安全距离的方法。通过计算给出不同无阻流量、不同硫化氢体积含量的20种条件下的天然气钻井井口安全距离,并应用该模型对某含硫气井井口安全距离进行了计算。实例表明,该方法具备实用性,值得在天然气井选址规划中推广和使用。     

基于道化学法的大型合成氨装置安全评价

根据道化学公司火灾、爆炸危险指数的基本原理。用VH6．0开发的安全评价软件DowSE1．0，对某大型合成氨装置进行安全评价，得出其安全措施补偿前后的火灾、爆炸指数F＆EI以及危险暴露面积，危害系数，危险等级，实际可能财产损失程度等指数。结果表明。合成氨装置中实际最大可能财产损失值都没有超过200万美元，气化系统在合成氨装置中实际最大可能财产损失值占损失替换值比例高达53％，超过了10％的相对危险值界限。说明在引进国外技术时应注重其安全防范配套措施消化吸收，并结合实际采取切实可行的安全措施，降低合成氨装置的风险程度。     

岷江上游生态脆弱性驱动力分析

作为长江上游重要的生态屏障,岷江上游是典型的生态环境脆弱区。选取了测度岷江上游生态脆弱性的20个指标、25个样本年的2500个数据,采用逆向测度法构建了岷江上游生态脆弱性的测度指标体系,运用因子分析法得到了影响岷江上游的六大驱动因子:生态环境背景状况、人口承载与结构水平状况、水土流失状况、土地垦殖与利用状况、产业结构水平状况、投资水平与结构状况,为岷江上游生态脆弱区恢复重建及经济社会发展提供了科学依据。     

DIN Retention‐Transport Through Four Hydrologically Connected Zones in a Headwater Catchment of the Upper Mississippi River1

Abstract: Dissolved inorganic nitrogen (DIN) retention‐transport through a headwater catchment was synthesized from studies encompassing four distinct hydrologic zones of the Shingobee River Headwaters near the origin of the Mississippi River. The hydrologic zones included: (1) hillslope ground water (ridge to bankside riparian); (2) alluvial riparian ground water; (3) ground water discharged through subchannel sediments (hyporheic zone); and (4) channel surface water. During subsurface hillslope transport through Zone 1, DIN, primarily nitrate, decreased from ～3 mg‐N/l to <0.1 mg‐N/l. Ambient seasonal nitrate:chloride ratios in hillslope flow paths indicated both dilution and biotic processing caused nitrate loss. Biologically available organic carbon controlled biotic nitrate retention during hillslope transport. In the alluvial riparian zone (Zone 2) biologically available organic carbon controlled nitrate depletion although processing of both ambient and amended nitrate was faster during the summer than winter. In the hyporheic zone (Zone 3) and stream surface water (Zone 4) DIN retention was primarily controlled by temperature. Perfusion core studies using hyporheic sediment indicated sufficient organic carbon in bed sediments to retain ground water DIN via coupled nitrification‐denitrification. Numerical simulations of seasonal hyporheic sediment nitrification‐denitrification rates from perfusion cores adequately predicted surface water ammonium but not nitrate when compared to 5 years of monthly field data (1989‐93). Mass balance studies in stream surface water indicated proportionally higher summer than winter N retention. Watershed DIN retention was effective during summer under the current land use of intermittently grazed pasture. However, more intensive land use such as row crop agriculture would decrease nitrate retention efficiency and increase loads to surface water. Understanding DIN retention capacity throughout the system, including special channel features such as sloughs, wetlands and floodplains that provide surface water‐ground water connectivity, will be required to develop effective nitrate management strategies.     

Hydrological Connectivity Between Headwater Streams and Downstream Waters: How Science Can Inform Policy1

Abstract: In January 2001, the U.S. Supreme Court ruled that the U.S. Army Corps of Engineers exceeded its statutory authority by asserting Clean Water Act (CWA) jurisdiction over non‐navigable, isolated, intrastate waters based solely on their use by migratory birds. The Supreme Court’s majority opinion addressed broader issues of CWA jurisdiction by implying that the CWA intended some “connection” to navigability and that isolated waters need a “significant nexus” to navigable waters to be jurisdictional. Subsequent to this decision (SWANCC), there have been many lawsuits challenging CWA jurisdiction, many of which are focused on headwater, intermittent, and ephemeral streams. To inform the legal and policy debate surrounding this issue, we present information on the geographic distribution of headwater streams and intermittent and ephemeral streams throughout the U.S., summarize major findings from the scientific literature in considering hydrological connectivity between headwater streams and downstream waters, and relate the scientific information presented to policy issues surrounding the scope of waters protected under the CWA. Headwater streams comprise approximately 53% (2,900,000 km) of the total stream length in the U.S., excluding Alaska, and intermittent and ephemeral streams comprise approximately 59% (3,200,000 km) of the total stream length and approximately 50% (1,460,000 km) of the headwater stream length in the U.S., excluding Alaska. Hillslopes, headwater streams, and downstream waters are best described as individual elements of integrated hydrological systems. Hydrological connectivity allows for the exchange of mass, momentum, energy, and organisms longitudinally, laterally, vertically, and temporally between headwater streams and downstream waters. Via hydrological connectivity, headwater, intermittent and ephemeral streams cumulatively contribute to the functional integrity of downstream waters; hydrologically and ecologically, they are a part of the tributary system. As this debate continues, scientific input from multiple fields will be important for policymaking at the federal, state, and local levels and to inform water resource management regardless of the level at which those decisions are being made. Strengthening the interface between science, policy, and public participation is critical if we are going to achieve effective water resource management.