高强度模拟酸雨量对珠三角地区潮土中重金属元素释放的影响

采用平均离子强度下30年雨量的模拟酸雨淋滤珠江三角洲潮土,电感耦合等离子体质谱法测定重金属元素,研究潮土0~90 cm处各节土壤柱中重金属镉、钴、铜、锌、铅、砷、钛、钒、铬、锰等元素的释放情况。研究表明,在高强度模拟酸雨淋滤下,潮土中重金属元素的释放情况存在较大差异。长期的酸雨淋滤,土壤中的镉、钴、铜、锌和铅在不同深度均有不同程度的淋失;砷、钛、钒、铬、锰等元素不会造成大量的淋失。利用这种差异可以评估重金属元素对环境的潜在影响,为农田生态系统的预警预测提供依据。     

Research on the critical conditions for clay particle release during saline aquifer freshening process

Water sensitivity phenomenon occurs during saline aquifer freshening process in seawater intrusion area, and clay particles released in the phenomenon can damage the infiltration capacity of the aquifer. In order to find out the factors and mechanisms for clay particle release, laboratory column infiltration experiments simulating saline aquifer freshening process were designed to measure the critical conditions(critical flow velocity, critical salt concentration and critical ionic strength) and force analysis for clay particle according to DLVO electric double layer theory was employed to illustrate the mechanisms for particle release. The research results showed that critical flow velocity for clay particle release is influenced by salt concentration of injecting solution. When salt concentration of injecting solution is very high, clay particles are not released, indicating that there does not exist a critical flow velocity in this situation. As salt concentration of injecting solution decreases, particles start to be released. The critical salt concentration for clay particle release is 0.052 mol L-1 in our work, which was determined by a constant-flux experiment for stepwise displacement of high concentration Na Cl solution. The critical ionic strength for clay particle release decreases as Ca2+ molar content percentage of the mixed solution of Na Cl and Ca Cl2 increases following the first-order exponential decay equation y = 0.0391e-0.266 x + 0.0015.     

崇左市预警信号发布现状及探讨

统计2008-2013年以来崇左市下辖江州区、扶绥县、天等县、大新县、宁明县、龙州县、凭祥市七县（市、区）,几种常用的气象灾害预警信号发布现状以及实际工作中遇到的问题展开谈论,探讨预警信号发布工作面临的新形势,并提出新形势下预警信号发布工作相应的对策和措施,从而更好的做好＂气象灾害预警信号＂的发布工作,减少气象灾害所带来的损失。     

Lacustrine basin unconventional resource plays: Key differences

There has been a revival in hydrocarbon source rock characterization and development associated with growing interest in unconventional resources, where these fine-grained organic-rich rocks act as both source and reservoir. To-date, the exploration focus on shale reservoirs has been largely on marine systems. Lacustrine source rocks for conventional resources are geographically important, dominating regions such as China, Indonesia, and Brazil's resource-base. However, they have been generally untested for unconventional resources.There are a number of key differences in the nature of these hydrocarbon systems that should be considered when assessing whether lacustrine systems may represent future unconventional opportunities in areas where the conventional resource-base is dominated by lacustrine-sourced oil. Among the key differences between these depositional systems is the greater sensitivity to high frequency climatic variability within lacustrine systems. Lacustrine systems are highly sensitive to changes in the balance between precipitation and evaporation, which may lead to rapid changes in lake level, potentially exceeding 600 m. These changes in depositional conditions are geologically rapid and may occur over periods of thousands of years. Such changes can reduce the areal extent of potentially thick source rock intervals to only those portions of a basin where a permanent deep lake was present. Thus the core unconventional target area may be geographically limited compared with their marine counterpart. Although potentially areally limited, a review of many lacustrine source rocks suggests that their thicknesses are often significantly greater than marine source rocks. An examination of the more distal portions of lacustrine systems, where better source rock potential is present reveals that there is generally limited connectivity between source and conventional reservoir. In these settings, such as the Wind River basin (Waltman Shale), the hydrocarbons remain trapped within the shales, potentially leading to over-pressured hydrocarbon charged systems. Such conditions suggest that although areally limited, viable unconventional targets may exist, if suitable reservoir conditions are present. Finally, the character of the oils produced is different in these settings, with lacustrine oils being waxy and displaying different hydrocarbon generation and cracking kinetics. High wax oils display distinct flow characteristics, being more viscous, and may offer different production challenges than their non-waxy marine equivalents. Additionally, differences in their cracking kinetics may indicate that the timing of gas generation for shale gas plays may differ significantly from marine systems.     

Impact of Anthropogenic Heat Release on Regional Climate in Three Vast Urban Agglomerations in China简

We simulated the impact of anthropogenic heat release （AHR） on the regional climate in three vast city agglomerations in China using the Weather Research and Forecasting model with nested high-resolution modeling.Based on energy consumption and high-quality land use data,we designed two scenarios to represent no-AHR and current-AHR conditions.By comparing the results of the two numerical experiments,changes of surface air temperature and precipitation due to AHR were quantified and analyzed.We concluded that AHR increases the temperature in these urbanized areas by about 0.5℃-1℃,and this increase is more pronounced in winter than in other seasons.The inclusion of AHR enhances the convergence of water vapor over urbanized areas.Together with the warming of the lower troposphere and the enhancement of ascending motions caused by AHR,the average convective available potential energy in urbanized areas is increased.Rainfall amounts in summer over urbanized areas are likely to increase and regional precipitation patterns to be altered to some extent.     

羟基磷灰石对水溶液中Fe3+的吸附动力学及热力学研究

研究了羟基磷灰石(HAP)对水溶液中Fe3+的吸附动力学及热力学。研究表明,HAP对水溶液中Fe3+的吸附符合Langmiur等温吸附,ct/q=0.006 4 ct+0.018 3;该吸附反应符合一级反应动力学方程,ln CR=-0.043 5 t+4.324 4;吸附反应活化能为Ea=36.26 k J/mol;标准摩尔反应焓为正值表明反应过程吸热;当温度大于285.7 K时,吉布斯自由能小于0,反应可自发进行。     

基于热重分析的菱镁矿分解动力学解析

本文利用热重(TG)分析方法,探讨了菱镁矿的热分解过程。根据热微商(DTG)曲线峰顶温度,结合Kissinger及Ozawa-Doyle方法拟合计算得到菱镁矿热分解的活化能和指前因子(lgA)分别为211.55 kJ/mol和11.07s-1。依次采用单曲线拟合、多元非线性拟合及Malek方法判定得出菱镁矿热分解过程属于三维相界反应模型(R3),其动力学方程为:dα/d T=(1011.07/β)·e-211.55×103/(8.314×T)·3(1-α)2/3。     

The Metastable Phase Equilibria of the MeX-MgCl_2-H_2O Systems

正1 Introduction The Pingluoba brine,which characterized as high concentration with sodium,potassium,boron,lithium,and rubidium,possess great development value.The main composition of the brine can be summarized to the     

Relativistic gravitational collapse of a cool white dwarf with allowance for the neutronization kinetics

We consider and numerically solve the problem of the relativistic gravitational collapse of a spherically symmetric cool nonrotating white dwarf with allowance for the neutronization kinetics. We propose a model equation of state and analyze the neutronization kinetics under simplifying assumptions. A comprehensive mathematical model is constructed for the phenomenon. The system of equations is integrated numerically. The gravitational collapse of a white dwarf that lost its stability is shown to lead to the envelope ejection and to the final state of a hot static neutron star. For comparison, we solve the problem with an equilibrium equation of state. We show that in this case, the entire mass ultimately goes under the gravitational radius to form a black hole.     

Biodegradation and transport of benzene,toluene, and xylenes in a simulated aquifer: comparison of modelled and experimental results

Both laboratory experiments and numerical modelling were conducted to study the biodegradation and transport of benzene–toluene–xylenes (BTX) in a simulated semi‐confined aquifer. The factors incorporated into the numerical model include advection, hydrodynamic dispersion, adsorption, and biodegradation. The various physico‐chemical parameters required by the numerical model were measured experimentally. In the experimental portion of the study, BTX compounds were introduced into the aquifer sand. After the contaminants had been transported through the system, BTX concentrations were measured at 12 equally spaced wells. Subsequently, microorganisms obtained from the activated sludge of a sewage treatment plant and cultured in BTX mixtures were introduced into the aquifer through the 12 sampling wells. The distribution data for BTX adsorption by the aquifer sand form a nonlinear isotherm. The degree of adsorption by the sand varies, depending on the composition of the solute. The degradation time, measured from the time since the bacteria were added to the aquifer until a specific contaminant was no longer detectable, was 35–42 h for BTX. The dissolved oxygen, after degradation by BTX compounds and bacteria, was consumed by about 40–60% in the entire simulated aquifer; thus the aerobic conditions were maintained. This study provides insights for the biodegradation and transport of BTX in aquifers by numerical modelling and laboratory experiments. Experimental and numerical comparisons indicate that the results by Monod degradation kinetics are more accurate than those by the first‐order degradation kinetics. Copyright © 2002 John Wiley & Sons, Ltd.