福建暴雨洪灾时空变化与区域划分的初步研究

根据福建省暴雨洪涝灾害数据库资料，重建了1971—2005年福建暴雨洪灾的时空格局，在此基础上，基于自然灾害系统理论，以县域为单元，根据综合性与主导因素相结合的原则，采用自下而上的方法对福建暴雨洪灾进行了区域划分。结果表明：福建洪涝灾害的年际变化呈波动上升趋势，与暴雨次数的年际变化并不一致；年内非台风暴雨洪涝灾害有71．2％集中在4—6月份，台风暴雨洪涝灾害有81.3％集中在7—9月份，群发性强；空间上东西分异明显，东部以台风暴雨洪灾为主，区内根据危险性差异划分为4个二级区；西部以非台风暴雨洪灾为主，区内依据危险性差异划分为3个二级区。分阶段研究表明，洪涝灾害的分布范围由沿海向内陆扩展，并与暴雨频次和持续时间呈不同步增长，反映了福建的洪涝灾害是主要致灾因子暴雨和承灾体共同作用的结果，承灾体的脆弱性加大了洪涝灾害灾情，福建暴雨洪涝灾害的时空格局和区域划分可为防灾减灾规划提供科学参考。     

考虑气液置换的压回法气井压井过程对井底压力的影响

为在压回法气井压井计算中进一步贴合现场实际情况,提出新的压回法气井压井过程计算方法.在压井过程中,考虑压井液与侵入井筒的气体发生置换,导致井筒流体自上而下分布为液-气液2相-气-气液2相的实际问题,建立压井过程模型,并对井底压力的变化进行计算分析.结果表明:发生气液置换对压回法压井过程井底压力以及注入压力具有明显影响,...     

基于文献计量法的火灾灾害研究现状及展望

为了解火灾灾害研究领域的发展现状及未来趋势,基于多种可视化工具,对2014—2020年期间,火灾灾害领域内的发文态势、学术合作、学术热点、研究趋势等内容展开分析。研究结果表明：该时期内,火灾领域发文量呈持续上升趋势;我国科研活力及持续发展性均处于世界前沿地位,中国科学技术大学是全球发文量和合作活跃度较高的机构;载发文量排名前5的期刊研究方向和出刊数量整体呈现出一定差异性和波动性;研究热点涵盖基于无人飞行器的森林火灾(野火)侦测调查、基于火灾现场整体模型搭建的计算机模拟火灾事故技术与研究、火灾下建筑物构件的耐火及倒塌行为研究、池火燃烧特性试验及现象调查、火灾碎片实验与分析方法,研究内容总体呈现具体化、精细化;目前火灾领域研究的前沿方向为热释放速率研究、基于数值模拟的火灾事故研究、对点火器(源)的调查研究、基于数值模拟的火灾事故调查等;根据分析推测该领域未来的科研活跃度将继续上升。研究结果可为火灾灾害领域内相关学者把握学科现状,研讨未来发展提供参考依据。     

Monitoring of environmental exposure to polycyclic aromatic hydrocarbons: a review

Polycyclic aromatic hydrocarbons (PAHs) are a large group of organic compounds with two or more fused aromatic rings. They have a relatively low solubility in water, but are highly lipophilic. Most of the PAHs with low vapour pressure in the air are adsorbed on particles. When dissolved in water or adsorbed on particulate matter, PAHs can undergo photodecomposition when exposed to ultraviolet light from solar radiation. In the atmosphere, PAHs can react with pollutants such as ozone, nitrogen oxides and sulfur dioxide, yielding diones, nitro- and dinitro-PAHs, and sulfonic acids, respectively. PAHs may also be degraded by some microorganisms in the soil. PAHs are widespread environmental contaminants resulting from incomplete combustion of organic materials. The occurrence is largely a result of anthropogenic emissions such as fossil fuel-burning, motor vehicle, waste incinerator, oil refining, coke and asphalt production, and aluminum production, etc. PAHs have received increased attention in recent years in air pollution studies because some of these compounds are highly carcinogenic or mutagenic. Eight PAHs (Car-PAHs) typically considered as possible carcinogens are: benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene (B(a)P), dibenzo(a,h)anthracene, indeno(1,2,3-cd)pyrene and benzo(g,h,i)perylene. In particular, benzo(a)pyrene has been identified as being highly carcinogenic. The US Environmental Protection Agency (EPA) has promulgated 16 unsubstituted PAHs (EPA-PAH) as priority pollutants. Thus, exposure assessments of PAHs in the developing world are important. The scope of this review will be to give an overview of PAH concentrations in various environmental samples and to discuss the advantages and limitations of applying these parameters in the assessment of environmental risks in ecosystems and human health. As it well known, there is an increasing trend to use the behavior of pollutants (i.e. bioaccumulation) as well as pollution-induced biological and biochemical effects on human organisms to evaluate or predict the impact of chemicals on ecosystems. Emphasis in this review will, therefore, be placed on the use of bioaccumulation and biomarker responses in air, soil, water and food, as monitoring tools for the assessment of the risks and hazards of PAH concentrations for the ecosystem, as well as on its limitations.     

利用景观梯度法分析张家港市城市景观变化

在遥感与GIS技术平台的支持下,利用景观格局梯度法分析了张家港市各土地利用类型的景观格局及其时空分布特征.研究结果表明,2002-2006年,张家港市城市景观格局总体变化明显,城镇用地增长22.10%,农业用地则减少14.96%.在空间上,呈现出城市一城乡交错带一农业区的变化特征;在时间上,整体样带体现出斑块密度升高、...     

兰州市土地利用变化及生态服务价值

以典型河谷型大城市兰州市为例,在RS和GIS技术支持下,剖析了1997-2009年该市各县区土地利用及其变化情况。在此基础上,参考Costanza等生态系统服务价值计算方法和中国陆地生态系统单位面积服务价值表,分析r近12年来研究区土地利用变化对生态系统服务价值的影响及其变化情况。结果表明：1997-2009年兰州市林地增长面积最大,主要来源于耕地的转出及两山绿化,其次为建设用地,主要是对耕地、草地和未利用地的占用;土地利用类型面积减少最大的是耕地,主要转变为林地、草地和建设用地。土地利用变化引起生态系统服务价值及GDP变化,其分别从1997年的59．99亿元,210．27亿元上升到2009年的61．52亿元,920亿元。总体呈增长趋势,表明该区域生态环境整体向良性方向发展。     

Coupling a land use model and an ecosystem model for a crop-pasture zone

This paper describes the development of a land use model coupling ecosystem processes. For a given land use pattern in a region, a built-in regional ecosystem model (TESim) simulates leaf physiology of plants, carbon and nitrogen dynamics, and hydrological processes including runoff generation and run-on re-absorption, as well as runoff-induced soil erosion and carbon and nitrogen loss from ecosystems. The simulation results for a certain period from 1976 to 1999 were then used to support land use decisions and to assess the impacts of land use changes on environment. In the coupling model, the land use type for a land unit was determined by optimization of a weighted suitability derived from expert knowledge about the ecosystem state and site conditions. The model was applied to the temperate crop-pasture band in northern China (CCPB) to analyze the interactions between land use and major ecosystem processes and functions and to indicate the added value of the feedbacks by comparing simulations with and without the coupling and feedbacks between land use module and ecosystem processes. The results indicated that the current land use in CCPB is neither economical nor ecologically judicious. The scenario with feedbacks increased NPP by 46.78 g C m⁻² a⁻¹, or 32.23% of the scenario without feedbacks, also decreased soil erosion by 0.65 kg m⁻² a⁻¹, or 23.13%. Without altering the regional land use structure (proportions of each land use type). The system developed in this study potentially benefits both land managers and researchers.     

Effect of biocides on the precipitation of calcium fluoride in the presence of anionic copolymeric inhibitors

The inhibitory efficiency of anionic copolymers and the effect of the biocides sodium hypochlorite, glutaraldehyde, and tris(hydroxymethyl)nitromethane on the precipitation behavior of calcium fluoride (CaF₂) were studied. The efficiency of polymeric inhibitors was traced from conductivity measurements by using half-life (t_1/2) method. X-ray diffraction parameters have been measured for calcium fluoride scale minerals. An anionic copolymer (K-798) acts as one of the best inhibitors for the precipitation process of the calcium fluoride in water as compared to K-775. It is assigned to the fact that the copolymer (K-798) contains both sulfonic acid and sulfonated styrene groups while the polymer (K-775) having only the sulfonic acid group. It was further observed that the biocides have no appreciable effect on the performance of the anionic polymeric inhibitors.     

森林植被对降水水化学的影响

综述了森林植被各个层次对降水水化学影响的主要研究成果,并指出了目前该方面研究存在的问题及今后需要努力的方向。大量集中在乔木层的研究表明,与林外雨比较,穿透雨、树干茎流中多数元素的浓度均呈增加的趋势,浓度大小的总趋势为树干茎流>穿透雨>林外降雨,K、Mg、Mn等表现突出,浓度可增加10倍以上;影响元素浓度变化因素包括降水特征、林分类型、大气状况等;具体到某一种元素,不同区域、不同林型间研究结果差异很大,很难得出一致的结论。对灌草层和枯落物层吸附淋溶作用研究较少,也就不能正确评价森林植被对降水水化学的综合效应。因此,在空间尺度上,要加强不同区域森林植被各个层次的研究;在时间尺度上,短时间的观测缺乏代表性,长期定位观测更具科学性。此外,目前的研究,尤其是国内的研究,只是对现象的揭示,缺乏过程及机理的深入研究,限制了我们对森林植被的内在运行机制和客观规律的正确认识。     

Translating the 10 golden rules of reforestation for coral reef restoration

Efforts are accelerating to protect and restore ecosystems globally. With trillions of dollars in ecosystem services at stake, no clear framework exists for developing or prioritizing approaches to restore coral reefs even as efforts and investment opportunities to do so grow worldwide. Restoration may buy time for climate change mitigation, but it lacks rigorous guidance to meet objectives of scalability and effectiveness. Lessons from restoration of terrestrial ecosystems can and should be rapidly adopted for coral reef restoration. We propose how the 10 golden rules of effective forest restoration can be translated to accelerate efforts to restore coral reefs based on established principles of resilience, management, and local stewardship. We summarize steps to undertake reef restoration as a management strategy in the context of the diverse ecosystem service values that coral reefs provide. Outlining a clear blueprint is timely as more stakeholders seek to undertake restoration as the UN Decade on Ecosystem Restoration begins.