挠曲线复位的微分方程解法求梁的位移

梁位移求解的方法主要有两种：积分法和叠加法。积分法的困难是当多个荷载同时作用时，要按控制面分段列弯矩方程，这样，两次积分时带来的积分常数较多，导致依边界条件、连续条件定这些常数时要解多个联立方程，计算繁杂。梁位移求解的叠加法是借用典型荷载下梁已知积分结果来进行对应位置位移的叠加，具体是查转角方程、挠曲线方程表格。从表中知，梁任一位置处的位移方程大多是多次多项式，很难记忆，故离开表格便无法采用。本文找到了一种新的方法求梁的位移，通过设置比拟梁，使比拟梁的挠曲线复位于原梁，从而建立了相应的微分方程，求解此方程后便可得梁的位移，避开了分段多次积分或查表的弱点。     

机械卡盘设计中的计算误差分析与应用

通过对普通机构二维力因素影响的分析，利用修正公式计算求值，以修正单因素影响最大值计算所产生的误差。利用这一计算方法，对CD—3型钻机卡盘进行了计算，得到了正确的设计结果，说明用修正公式对多因素影响采用单因素影响最大值计算进行修正是可行的。     

改进的最小二乘法在水文分析计算中的应用

在水分析计算中，经常涉及到变量之间的线性或非线性拟合，而在拟合各种特性曲线时，通常应用以实测资料与拟合曲线间的误差平方和最小作为目标函数的方法——最小二乘法，但这种方法忽视了所有实测点应与拟合曲线间的相对误差尽量不超过某一百分比的原则，为了达到上述要求，提出了非线性的加权最小二乘法及线性相关方程的最小距离平方和法，探讨改进了传统的最小二乘法达到优化的效果。最小距离平方和法与常用的图解法相比，本法所得成果较为客观；与传统的单方向(x或y方向)最小二乘回归法相比，所求线性方程不会因坐标系的选取而改变。最后应用算例进行了初步讨论。     

基于脉冲频响函数的MATLAB动力方程求解方法

提出一种基于脉冲频响函数并利用MATLAB求解的方法，由于脉冲频响函数利用卷积公式进行动力微分方法计算，因此，从理论上讲，它适合于任意外力下的动力方程求解，同时，MATAL又提供了卷积函数conv，所以，在MATLAB下求解动力方程将变得十分容易。     

锚杆动测问题的数值解

建立了锚杆动测问题的有限元模型，并对锚杆中的缺陷进行了数值模拟，获得了位移场的数值解。对该解在时域和频域范围内的讨论表明，锚杆中的缺陷将引起动测曲线一系列的变化，为现场动测曲线的识别提供了依据。     

Atmospheric nitrogen inputs into the North Sea: effect on productivity

The ANICE (Atmospheric Nitrogen Inputs into the Coastal Ecosystem) project addressed the atmospheric deposition of nitrogen to the North Sea, with emphasis on coastal effects. ANICE focused on quantifying the deposition of inorganic nitrogen compounds to the North Sea and the governing processes. An overview of the results from modelling and experimental efforts is presented. They serve to identify the role of the atmosphere as a source of biologically essential chemical species to the marine biota. Data from the Weybourne Atmospheric Observatory (UK) are used to evaluate the effect of short episodes with very high atmospheric nitrogen concentrations. One such episode resulted in an average deposition of 0.8 mmol N m⁻² day⁻¹, which has the potential to promote primary productivity of 5.3 mmol C m⁻² day⁻¹. This value is compared to long-term effects determined from model results. The total calculated atmospheric deposition to the North Sea in 1999 is 948 kg N km⁻¹, i.e. 0.19 mmol N m⁻² day⁻¹ which has the potential to promote primary productivity of 1.2 mmol C m⁻² day⁻¹. Detailed results for August 1999 show strong gradients across the North Sea due to adjacent areas where emissions of NO_x and NH₃ are among the highest in Europe. The average atmospheric deposition to the southern part of the North Sea in August 1999 could potentially promote primary production of 2.0 mmol C m⁻² day⁻¹, i.e. 5.5% of the total production at this time of the year in this area of the North Sea. For the entire study area the atmospheric contribution to the primary production per m² is about two-third of this value. Most of the deposition occurs during short periods with high atmospheric concentrations. This atmospheric nitrogen is almost entirely anthropogenic in origin and thus represents a human-induced perturbation of the ecosystem.     

大同市区二十年地下水动态研究

本文首先分析了大同市地下水开采与地下水降深之间的对应关系，同时分析了影响地下水动态的其它因素，然后将地下水开采和大气降水量这两个影响地下水动态的主要因素与地下水动态进行复相关计算，求出相关方程，并进行不同开采量的地下水降深预测，最后根据这些地下水动态研究结果提出了解决大同市水问题几项对策建议。本文的研究结果同时表明，地下水动态研究非常必要且现实意义明显。通过动态变化可以了解地下水的补排及储水介质的变化情况，利用动态变化规律可以预测水文地质条件的变化趋势，根据地下水动态变化特点可采取有针对性的、灵活的取水方案。可以说，地下水动态研究成果在水资源的开发、利用、保护中具有极大的可利用价值。     

Neuzeitlicher Schadstofftrend: Polycylische aromatische Kohlenwasserstoffe (PAK) in aquatischen und terrestrischen Sedimenten

A Recent Contamination Trend: Polycylic Aromatic Hydrocarbons (PAHs) in Aquatic and Terrestrial Sediments Concentrations of polycylic aromatic hydrocarbons (PAHs) measured in aquatic sediments of small, medium‐sized or very large inland lakes, of estuaries as well as in terrestrial sediments from Germany, the UK, Finland, and the USA were plotted in 10 trend curves over the period from 1800 to 1990. The segments of the bore cores were dated for their deposition age. For comparability of the results, the trend is preferentially shown by the guide parameter fluoranthene. Until the 19th century, a constant background value of C_Fluo = 10…50 μg/kg was observed in all regions. Then a steep increase in concentration followed, reaching in the aquatic sediments a maximum in the period 1940 to 1965, while the individual fluoranthene values ranged widely from 90 to 2400 μg/kg. In several regions, a more or less distinct decrease superseded this maximum, although this development did not appear in terrestrial sediments, in one estuary, and in remote forest lakes in Finland. The trend curves reflect the atmospheric deposition of PAHs in airborne dust and in some cases the import through runoff via rivers. Thus, the sediment profiles depict the development of air pollution by pyrogenic contaminants over more than a century. Sediment profiles from rivers can be used only with a high degree of reservation, because of the irregularity and low representativity of the sedimentation.     

共线条件方程式教学中的几个问题

指出了共线条件方程式教学中应注意的一些问题：共线条件方程式是联立的两个平面方程式，存在双主距（fx,fy)时的几何概念，以及它的变换式与直接线性变换关系式的异同点。     

缺少控制点的卫星遥感对地目标定位

从单线阵推扫式传感器的成像机理出发，利用6个卫星轨道开普勒参数和3个传感器姿态角建立了推扫式卫星遥感影像坐标与其地面点在地心坐标系下的坐标关系式，即构像方程。按照所建立的构像方程，对某地区一景SPOT-5影像进行对地目标定位，获得了实地上83．392m的平面精度；利用单个地面控制点对卫星轨道开普勒参数和传感器姿态实施调整后，目标定位精度提高到14．217m。试验证实，所建立的构像方程是正确的,在卫星遥感对地目标定位中有较好的应用前景。