粉煤灰扰动样现场取样问题初步探讨

本文结合福州电厂粉煤灰室内试验结果分析，探讨粉煤灰扰动样现场取样及试验控制干密度的等问题，该电厂粉煤灰的沉积规律与其它电厂有所不同，灰料颗粒组细分布和距排灰口远近基本无关，取样也不能按以往经验进行。     

基于人工神经网络的黄河下游枯季径流预测研究

通过分析黄河下游枯季径流的影响因素 ,主要为花园口水文站径流量和下游的引黄量这两个因子 ,花园口水文站径流量和下游的引黄量可作为输入层中的影响因子 ,下游利津站的流量作为输出层。应用多层前向人工神经网络理论 ,构造四套枯季径流实时预测的BP神经网络模型 ,使用花园口—利津水文站 2 6年的完整序列测流资料训练和检验网络并用于预测     

登陆热带气旋引发的龙卷过程之个例分析

将卫星云图与物理量场相结合，对9909号热带风暴（WENDY）登陆北上并与西风带系统相互作用，引发上海东南部地区龙卷天气的过程进行分析研究，发现中低纬度系统的相互作用使WENDY倒槽得以维持和发展，并对WENDY残存低压长时间存在并北上起重要作用，当WENDY低压北上与西风带系统相接、叠加时，高层辐散、低层辐合的良好环境使WENDY环流内的对流云团进一步加强发展，中尺度干涌的涌入促使强对流云团群合并发展，并加剧对流辐合体内水平风切变，最终导致龙卷产生。     

初夏昆明罕见大暴雨分析

１９８６年６月６－７日，云南昆明出现了１９５１年以来一次最大暴雨。天气学与诊断分析表明，初夏云南可产生单点局地大暴雨，量级与盛夏、秋季相当。５００ｈＰａ干冷槽东移，７００ｈＰａ双涡吸引旋转西移，地面弱冷空气诱发静止锋锋生，强垂直风切变，昆明上空出现正反环流圈是该次过程的主要特征，与低纬度原地区区域性大－暴雨特征不同。     

渗透蒸馏浓缩柠檬酸

渗透蒸馏是适用于浓缩生物制品的一种新型膜过程．以ＮａＣｌ—柠檬酸稀溶液为研究体系，对渗透蒸馏的传质过程进行了研究，实验结果表明，水通量大于６７Ｋｇ／ｍ２·ｄ，柠檬酸可由３００ｇ／Ｌ浓缩到５００ｇ／Ｌ以上，同时还探索了渗透蒸馏和膜蒸馏浓缩柠檬酸的集成膜过程．     

控制粉煤灰密实度以替代砂类土的原位测试

本文是一例研究粉煤灰替代排水砂沟中以黄砂为材料的原位试验。通过建立静力触探比贯入阻力与干容重的相关关系,找出达到设计要求的7.5 KN/m干容重的最佳夯实击数(振密遍数),从而有效地控制了粉煤灰的密实度。     

Heat extraction from hot,dry, crustal rock

Natural heat stored in the earth's interior represents an essentially inexhaustible energy supply which, at usefully high temperatures, is accessible at practical drilling depths from almost anywhere on the earth's land surface. The problems of extracting and using this heat are those of engineering and economics, and can be expected to vary with the local geology and value of thermal energy. The first major experimental system designed to investigate these problems in one common type of geologic environment has recently been completed in the crystalline rock underlying the Jemez Plateau of northern New Mexico. It consists principally of two boreholes connected at a depth of about 2.7 km by a system of hydraulic fractures produced in granitic rock at a temperature of approximately 185°C. Cool water injected through one hole is heated as it flows through the fractures, and is recovered through the second hole as pressurized, superheated water. In a surface heat-exchange system now being completed, this heat will be extracted and the cool water reinjected to maintain a continuous, closed, pressurized-water energy-extraction loop.     

膨润土加砂混合物干燥收缩特征及缩裂机制研究

膨润土加砂混合物作为核废料储存库缓冲材料,在库内高温高吸力条件下易干燥收缩,对工程安全运营有着重要影响,研究其收缩特性具有实际意义。以砂-膨润土混合物的饱和压实样为研究对象,采用自制恒温箱控制其收缩进程,分析含砂量及干密度对混合物收缩特性的影响。研究结果表明:干燥―收缩过程水分蒸发可分为减速阶段与残余阶段。减速阶段内水分迁出受控于干密度,而最终残余含水率主要受膨润土含量的影响。增加初始干密度和降低膨润土含量可使混合物变形协调,减少收缩变形的各向异性。膨润土含量M和初始干密度ρ是影响干燥―收缩过程的重要物理量,与Cornelis收缩模型中的拟合参数及最终孔隙比e_0具有很好的相关性。同等干密度条件下,随膨润土含量降低,压实膨-砂混合样的微观结构形态趋于致密化的趋势,从而有效地抑制了干燥收缩过程中裂隙发育与演化程度。     

干耦合超声波检测及波初至的自动拾取

目前岩石力学参数测定，受限于探头及数据采集设备，多在实验室环境完成，同时，传统超声收发探头对接触面平整度要求较高，需要对岩石表面打磨处理，且需要涂抹导声糊。这些都极大限制了超声测量系统的应用范围。为实现对岩石钻孔内的长效监测，对声波发射、接收机制及岩石内超声信号的频域特性进行分析，通过AIC算法拾取波前初至，利用小波去噪和改进AIC法（NAIC）求波初至到达精确时间，研究了基于干耦合岩石内部参数测量系统，在岩石内部实现了超声信号的发射接收、信号瞬态触发、高速采集，并将最终结果通过无线方式传输至数据记录仪。分别对Φ50 mm×100 mm花岗岩及砂岩岩样进行了超声波传输参数测量，Φ114 mm×280 mm花岗岩岩样测量距离分别为150、200 mm，利用NAIC、STA/LTA、MER、ETA 4种算法对该数据进行处理，并与第三方仪器测定结果进行比较。结果表明：基于干耦合声波测速采集系统，对不同工作接触面适应性较好，数据误差在规范允许范围内。小波降噪适用于背景干扰少、频率范围集中的超声接收信号，在到时拾取方面，除STA/LTA外其余3种算法在去噪后的到时拾取精度均得到有效提高，其中尤以NAIC法最为明显，到时平均误差由1.21 ?s锐减至0.19 ?s。     

Dusts from dry lakebeds： Mineralogical and geochemical characteristics of potential health concern

Dry lakebeds can be important sources of dusts that are potentially deleterious to the health of chronically exposed populations. The lakebeds accumulate and can concentrate natural and anthropogenic contaminants transported in particulate and dissolved form from the surrounding watersheds. The lakebed sediments are commonly enriched in respirable-size, detrital clay particles that can be disturbed to form dust. Evaporative concentration of ephemeral lake waters following intermittent wet periods, and of near-surface ground waters beneath some lakebeds, can enrich the sediments in diverse alkaline sulfate, carbonate, and chloride salts. Chemical reactions between alkaline evaporative waters and detrital silicates in the sediments can produce secondary silicates such as zeolites. Lakebeds with abundant salts and intermingled silicates can be highly susceptible to wind erosion, and repeated regeneration of salts in surface sediments may maintain a sustained source of salt-rich dusts. Potential health concerns arise in part from the large load of respirable particles emanating from some dry lakebeds. These concerns are exacerbated if the dusts have elevated metals, particularly metals enriched in soluble evaporative salts. For example, Owens-a dry lake, California, which was prior to mitigation the largest source of PM10 dust in the continental United States, contains elevated As in its dusts. Chemical leach tests using water and simulated gastric and lung fluids indicate that dry lakebed sediments and dusts can contain bioaccessible As, Mn, Al, Zn, Cu, Pb, U, W, Mo, and other potentially toxic metals. Another possible health issue is the occasional presence in lake sediments of secondary erionite, a fibrous zeolite associated with asbestos-related diseases. The potential presence of pathogens, as well＇as enrichments, bioaccessibility, and toxicity of pesticides and other organic pollutants in the dusts must also be evaluated. Earth scientists can help assess potential health effects of dry lakebed dusts by developing predictive models for dust generation and dust toxicity based on the geology,