试论工程地质超前预报与施工安全

塌方是较常见的矿山事故,往往造成人员伤亡和设备损坏。为此,探索了一种适用于中长期和短期工程地质超前预报相结合的方法,来预报巷道施工过程中可能塌方的地段,并提出预防措施的具体方法。这种方法,在实践中取得了较好的效果。     

Prediction Intervals for Estimates of Site Index Based on Ecosystem Type

/ British Columbia has an ecosystem classification system that classifies sites into site series. Foresters commonly measure the productivity of these sites by their site index. In British Columbia, site index is defined as the height of a stand at breast height age 50 and is usually estimated from height-age models. Biogeoclimatic site series/site index relationships are an increasingly popular method of estimating site index in British Columbia for stands where site index cannot be reliably estimated with height-age models. The precision of the predicted site index from these relationships can be evaluated with prediction intervals. This is done for the predicted site index of a single site, a group of sites, or the areally weighted site index of a group of sites. The methodology is also useful in determining the number of sites required to meet a specified precision. These prediction intervals will assist foresters in making sound forest management decisions.KEY WORDS: Biogeoclimatic Ecosystem Classification; Precision; Prediction interval; Site index; Site series     

GIS技术在环境影响评价中的应用

在对GIS系统的组成及主要功能进行介绍的基础上,综合性地阐述了GIS技术在环境影响评价中的应用。GIS技术可对环境影响进行模拟和预测,在环境影响评价中可对环境因素的确立、环境质量的描述和预测进行分析,并为环境政策的制定提供科学依据。     

上海市生活垃圾的处理现状及对策探讨

阐述了上海市目前生活垃圾收运及处理情况，对２０００年上海生活垃圾的产量作了预测，对生活垃圾处理对策的分析中，提出技术，资金和管理等方面的支持条件。     

灰色马尔柯夫模型在地表水体DO浓度预测中的应用

灰色马尔柯夫模型是一种随机预测模型，被广泛的应用于社会，经济的预测中，本文利用灰色马尔柯夫模型对某平原河段DO浓度进行了预测。经验证，灰色马尔柯夫模型适用于对地表水体DO浓度预测，并具有相当高的精度，在此基础上，作者提出了改进的建议，使模型更具有实用性和可操作性。     

A decision support system for wet soil cleaning

Newly developed software can predict the essential characteristics of the sand product resulting from the ex-situ washing of contaminated soil, dredging sludge or breaker sand. The system was designed for the Dutch situation and it works on the basis of readily available information. The primary output of the system is an assessment of the reusability of the sand product, which is obtained by comparing the prediction of the residual contamination and engineering quality with accepted levels and standards for building materials. The system also provides a ranking of potential applications for the sand with respect to treatment cost, the amount of recycled material or the environmental quality of the product. The software integrates soil cleaning expertise and unit process modelling in a way that allows varying levels of refinement of input data, ranging from a simple identification of the pollution source to a detailed particle size distribution of the contaminated soil. Tests on a database containing information on 117 processed batches of soil, dredging sludge and breaker sand show an 80% success rate in predicting cleanability, even though the input contamination levels were predominantly taken from (relatively inaccurate) in-situ data.     

基于B—P神经网络优化算法的城市环境空气中PM10浓度预测模型

将B—P神经网络应用于西安市环境空气中P10浓度预测,对网络结构和算法进行了优化,建立了PM10浓度预测模型。经验证模型精确度比较高,PM10日平均浓度绝对误差0．015～0．020mg／m^3,相对误差在-20％～20％范围内。     

Simple relationships between the ionization energies of one-, two- and three-electron ions of consecutive elements

The ionization energy of one-electron ions can be calculated from a well-known equation that is based on quantum mechanics and on the Bohr model, but no theoretically justified equation is available for the calculation of the ionization energies of multi-electron ions. I report here simple empirical relationships between the ionization energies of one-, two- and three-electron ions of elements whose atomic numbers are Z, Z + 1 and Z + 2. On the basis of these relationships, an equation was constructed for the calculation of the ionization energies of two- and three-electron ions (IE(2el)(Z) and IE(3el)(Z), respectively) as a function of Z only: [equation: see text] where N = the number of electrons, i.e. 2 or 3. For N = 3, this equation is only valid when Z > N, being inaccurate for the neutral Li atom. Graphs of the difference between calculated and experimental values of the ionization energies as a function of Z reveal inaccurate experimental results that are impossible to detect by inspection of the ionization energy itself. On the basis of the present results, more accurate values can be predicted for these ionization energies. A striking example is the inaccuracy of the traditional handbook value of IE(3el)(Fe).