贵州百花湖分层晚期有机质降解过程与溶解N2O循环

百花湖是一个具有季节性分层的富营养小型湖泊,在秋季湖水倒转期经常发生水质恶化事件,碳氮循环出现异常。文章研究特选择在秋初,湖泊分层开始消失时,测定了湖水中不同深度的N₂O,CH₄,CO₂,有机和无机碳同位素以及其他化学参数变化。结果发现:采样时百花湖在约6m和16m深度附近出现了两个温度不连续层(SDL和PDL),并影响到有机颗粒的沉降和分解。相对而言,有较多的有机质在这两个层内发生降解,但降解的途径有所不同,上部主要是有氧降解,下部则主要是无氧降解过程。N₂O的产生和消耗与有机质的降解过程完全对应:PDL层以上,ΔN₂O与AOU的线性关系反映了N₂O主要形成于硝化作用;PDL层以下反硝化作用导致N₂O严重不饱和;PDL内位于硝化作用和反硝化作用过渡带的N₂O峰,显然是硝化与反硝化联合作用的结果。PDL层内较大的CH₄浓度变化梯度,说明嗜甲烷细菌可能通过氧化NH+4贡献了部分N₂O。百花湖秋、冬季表层湖水N₂O都是过饱和的,都是大气N₂O的源,依据分子扩散模型计算湖泊N₂O的释放通量在12～14μmol/m·day之间,秋、冬季没有明显的差别。秋季底层湖水的反硝化作用是湖泊N₂O的汇,其消耗通量与表层的释放通量基本相当。     

Frequency domain modal analysis of earthquake input energy to highly damped passive control structures

A new complex modal analysis‐based method is developed in the frequency domain for efficient computation of the earthquake input energy to a highly damped linear elastic passive control structure. The input energy to the structure during an earthquake is an important measure of seismic demand. Because of generality and applicability to non‐linear structures, the earthquake input energy has usually been computed in the time domain. It is shown here that the formulation of the earthquake input energy in the frequency domain is essential for deriving a bound on the earthquake input energy for a class of ground motions and for understanding the robustness of passively controlled structures to disturbances with various frequency contents. From the viewpoint of computational efficiency, a modal analysis‐based method is developed. The importance of overdamped modes in the energy computation of specific non‐proportionally damped models is demonstrated by comparing the energy transfer functions and the displacement transfer functions. Through numerical examinations for four recorded ground motions, it is shown that the modal analysis‐based method in the frequency domain is very efficient in the computation of the earthquake input energy. Copyright © 2004 John Wiley & Sons, Ltd.     

Approximate modal decomposition of inelastic dynamic responses of wall buildings

Two approximate methods for decomposing complicated inelastic dynamic responses of wall buildings into simple modal responses are presented. Both methods are based on the equivalent linear concept, where a non‐linear structure is represented by a set of equivalent linear models. One linear model is used for representing only one vibration mode of the non‐linear structure, and its equivalent linear parameters are identified from the inelastic response time histories by using a numerical optimizer. Several theoretical relations essential for the modal decomposition are derived under the framework of complex modal analysis. Various numerical examinations have been carried out to check the validity of the proposed modal decomposition methods, and the results are quite satisfactory in all cases. Fluctuating bending moment and shear at any location along the wall height contributed by each individual vibration mode can be obtained. Modal contributions to shear and flexural strength demands, as well as the corresponding modal properties, under various seismic loading conditions can also be identified and examined in detail. Furthermore, the effects of higher vibration modes on seismic demands of wall buildings are investigated by using the modal decomposition methods. Several new insights into the complicated inelastic dynamics of multi‐story wall buildings are presented. Copyright © 2004 John Wiley & Sons, Ltd.     

基于小波分解的西太平洋副热带高压模糊推理预测

基于NCEP/NCAR再分析资料,讨论了西太平洋副高脊线与其前期位置的相互关系,并在此基础上用小波分解和自适应模糊推理方法,对副高脊线进行集成建模和预测.基于小波分解重构的副高脊线短期活动集成预测结果表明,该方法可有效降低预报难度,明显改进和提高了副高脊线短期活动的预报准确率.     

连续Domain的一个刻划

弱逼近元在完备格中有许多重要的性质，对于刻划连续格、完全分配格起着重要的作用。在Domain中引入弱逼近元的概念，研究了弱逼近元的一个重要性质，从而得到连续Domain的一个充要条件。最后，以Scott开滤子为基础，得到了连续Domain的一个刻划定理。     

近间距并行管线探测方法的效果对比

介绍了管线探测的几种方法,结合实例,对近间距并行管线的几种探测方法的效果进行了比较。     

柯坪河流域地下水资源的有效利用方式探讨

柯坪河流域分布于新疆境内，包括苏巴什盆地、柯坪盆地和阿恰山前地区．柯坪河是柯坪县最大的河流，上游名为苏巴什河，下游与红沙河汇合后称阿恰河．盆地与山前平原由柯坪河串起，水资源沿途不断汇入，并在不同河段有反复出露入渗．流域内无高山冰川，中山区降水是水资源的唯一来源．流域内水质普遍较差，溶解性总固体含量由北西向南东逐渐增高，当地居民生活饮用水供水水质不能满足生活饮用水标准．根据当地的地下水水资源特点，采取合适的管理利用方式，可使得较低溶解性总固体含量地下水资源能够更有效的被利用．     

Asymptotic Analysis and Layer Decomposition for the Couplex Exercise

This document explores the possibilities of multiscale expansions and domain decomposition to solve part of the Couplex 1 exercise. We concentrate on the hydrostatic pressure and show that the slenderness of the domain and the large variations of the Darcy constants allows an analytical approximation which our test reveals to be true to relative errors smaller than 10^–3. The numerical tests are done in 2D with freefem+ and in 3D with freefem3D. Some considerations are also given for Iodine transport.     

A practical method for estimating dynamic soil stiffness on surface of multi‐layered soil

It is important to estimate the influence of layered soil in soil–structure interaction analyses. Although a great number of investigations have been carried out on this subject, there are very few practical methods that do not require complex calculations. In this paper, a simple and practical method for estimating the horizontal dynamic stiffness of a rigid foundation on the surface of multi‐layered soil is proposed. In this method, waves propagating in the soil are traced using the conception of the cone model, and the impulse response function can be calculated directly and easily in the time domain with a good degree of accuracy. The characteristics of the impedance, that is the transformed value to the frequency domain of the obtained impulse response, are studied using two‐ to four‐layered soil models. The cause of the fluctuation of impedance is expressed clearly from its relation to reflected waves from the lower layer boundary in the model. Copyright © 2005 John Wiley & Sons, Ltd.     

DZ-1型地质灾害土层含水量监测仪系统的研究与应用

高强度降雨和岩土层含水量过高是山体滑坡等地质灾害的主要诱因，为了更好地对这类地质灾害进行有效预测预报，研制了DZ-1型地质灾害土层含水量监测仪，介绍了该监测仪的工作原理、主要构成、技术性能、监测工艺技术及实际应用效果。