覆盖条件下旱作春玉米农田土壤细菌群落结构分析

秸秆和地膜覆盖会改变农田土壤碳氮循环等理化条件,而覆盖对参与碳氮循环的土壤微生物的影响还鲜有报道。本研究通过高通量测序,分析了黄土高原旱作玉米农田无覆盖、秸秆覆盖、地膜覆盖下土壤细菌群落组成,探讨了细菌介导的碳氮循环对覆盖的响应。结果表明秸秆覆盖增加了土壤细菌群落丰富度和多样性,且显著增加了分解纤维素的细菌(纤维弧菌属Cellvibrio)及介导固氮(根瘤菌属Rhizomicrobium、Chryseolinea)和硝化过程的细菌(亚硝化螺菌属Nitrosospira)丰度(p0.05);地膜覆盖增加了土壤细菌丰富度,但降低了细菌多样性,且显著增加了介导土壤硝化作用的硝化螺菌属Nitrospira的丰度(p0.05)。本结果为土壤中微生物介导的碳氮循环研究提供了理论依据。     

MM5与CALMET对北京地区风能资源的初步模拟

利用MM5与CALMET模拟了北京地区10、30、50和70 m高度的风速和风功率密度分布,结果表明：各高度层风速与风功率密度的地域分布具有一致性,模拟的风速最大区位于门头沟西北部,而昌平西部、房山北部及延庆西部的风速次之,风速最小区位于顺义和东部城区;风功率密度的模拟显示京西地区和西北部地区的风资源较为丰富,北京东部、东南部和东北部及市区周边的风资源相对较小,开发潜力低。利用3座测风塔和3个气象站风速观测数据对模拟结果进行了初步检验,表明MM5与CALMET基本能模拟出风速的月变化和日变化特征,模拟和观测具有较好相关性,但模式存在对黄草梁和北梁地区模拟结果偏高、对涧沟地区模拟结果偏低的系统性误差,这可能与模拟区域地形复杂及模式自身分辨率不够等有关。     

综放采空区瓦斯与煤自燃多场耦合模拟研究

为了分析瓦斯与煤自燃多场耦合致灾特性,结合瓦斯抽采引起的采空区混合气体流动、气体组分渗流与采空区渗透率变化、固气两相热量传输等多物理过程,建立了基于综放采空区高位钻孔瓦斯抽采的热-流-化多场耦合数学模型,采用COMSOL软件模拟了综放采空区高位钻孔抽采瓦斯诱导煤自燃过程,阐明了瓦斯与煤自燃多场耦合致灾机理,得到了寸草塔二矿31102综放采空区氧化带范围与高温范围,并探讨了抽采强度对综放采空区氧浓度场与温度场的影响。研究结果表明:高位钻孔抽采瓦斯有效地降低了回风巷瓦斯浓度,保证了31102综放工作面安全高效回采。增大综放采空区高位钻孔抽采瓦斯强度不能保证煤自燃安全性,二者存在矛盾,在得到高效抽采瓦斯的同时,会造成进风侧氧化带宽度增加,采空区氧化带边界向深处蔓延,扩大煤自燃高温区域,漏风携氧充分的参与煤氧复合反应,采空区最高温度逐渐上升,煤自燃风险增大。     

长江流域资源环境与区域发展研究的回顾及展望

资源与环境问题是影响和制约可持续发展的核心问题。对《长江流域资源与环境》1995年至2004年10年间发表的学术论文进行了统计分析，就论文所涉及的研究领域、论文所运用的研究方法、研究机构的类型与地域分布等特征进行了全面的归类分析和总结研究。认为资源环境科学与区域可持续发展在未来的研究过程中必须实现促进学科的交叉与渗透，实现学科的系统集成与整合发展；寻找科学研究中的薄弱环节和新的生长点，积极开辟新的研究领域； 强化各项新技术、新手段的应用，提高科学研究的技术水平；深化区域研究，提高区域研究的综合性水平四大突破，才能适应和满足学科发展及社会发展的需要。     

工业土地利用与行业结构调整研究--基于昆山1400多家工业企业有效问卷的调查

以昆山市工业企业用地利用调查数据为依据。分析了现有昆山工业行业产业结构现状,并选取了6个相应的评价指标一在1414份问卷基础上,应用统计分析法,对所调查的工业内部不同17行业企业用地土地利用程度进行定量化评价。根据定量化评价结果并结合昆山市实际情况和有关的行业发展目标提出了产业调整和提高土地集约利用程度的途径与措施。     

电除尘器管状芒刺类电晕极电参数模拟计算

推导了不等线径、不等线距圆线组合电除尘器伏安特性计算关系,利用不等线径、不等线距圆线组合对管状芒刺类电晕极作了近似简化处理.采用静电场与电晕电场相叠加的办法建立了管状芒刺类电晕极电场分布的一种计算方法.与实验值对比表明,该方法的计算结果是可靠的.     

氧化速度对硫化矿石堆积体温度场变化影响的数值模拟方法研究

基于绝热温升模型和有限元数值计算方法,确定硫化矿石堆积体自燃预测指标,研究氧化速度对硫化矿石堆积体温度场的影响,建立硫化矿石堆积体温度场数值模型。计算结果表明,硫化矿石的氧化速度受到多重因素影响,通过调整参数m值反映堆积体中矿料氧化速度的快慢。随着m值的增大,氧化速度增大,堆积过程中以及后期堆放早期的最高温度值显著升高,而在堆放后期整体温度分布基本相同;其形心点的最高温度也增大,堆放后期该点温度值基本保持不变。     

An improved model for heavy gas dispersion using time-varying wind data: Mathematical basis,physical assumptions,and case studies

This study developed an improved model for the dispersion of released toxic gases, SLABi, based on the widely used model SLAB. Two major improvements enhanced the model's ability to represent observations. First, SLAB was upgraded to account for temporal variation in wind vectors. Thus, real-time changes in meteorological conditions can be considered in dispersion forecasting. Second, a source term module was developed and embedded in SLABi to standardize the procedure of emission calculation. Both the standard SLAB model and the SLABi model were applied to a case study to evaluate the impact of time-varying winds on the dispersion of released gases. The results showed that meteorology has a significant influence on the dispersion of released gases. The SLABi model can provide decision makers with timely and accurate guidance, so as to minimize hazards to people and the environment.     

佘山台地磁场长期变化基本特征

本文根据佘山台1900年~2004年地磁观测资料,对该地区F、H、Z、D地磁各要素长期变基本特征进行了分析总结,对深入研究地球基本磁场的变化有一定意义。     

Deep Geological CO2 Storage: Principles Reviewed, and Prospecting for Bio-energy Disposal Sites

The principles of hydrocarbon exploration and production provide well-established and tested principles and technologies to investigate storage of fluids in the subsurface. CO₂ can be stored in the subsurface using settings of: (A) thick permeable coal seams; (B) depleted oil and gas fields; (C) saline aquifers of regional extent, with an overlying seal. The North Sea Sleipner project shows that CO₂ can be injected into the pore space of deep geological aquifers deeper than 800 m at 1 Mt/yr, using established technology. Suitable sediment sequences of saline aquifers exist in all hydrocarbon-producing areas, are volumetrically much larger than exploited oil and gas fields, and hold the potential to easily store all worldwide CO₂ emissions until 2050. Geological principles are established to assess entire continents for candidate sites of CO₂ storage. This shows that opportunity may be widespread, but needs more specific local investigations. Onshore sub-Saharan Africa is considered the most problematic region – but even here there are potentially viable sediment sequences. No demonstration projects currently exist for CO₂ capture and storage using small-scale onshore facilities. A simple estimate, assuming CO₂ value of $20 per ton, suggests that single boreholes onshore may be viable over 20 years with supply rates of 100,000 ton CO₂ per year. In principle, atmospheric CO₂ could be captured by cultivated biomass, and co-fired in existing power stations. Or energy crops could be grown, CO₂ to be used, and stored deep below ground, in a country distant from an original fossil-fuel CO₂ emission site.