我国土地资源可持续发展与利用

通过对我国土地资源特征及利用现状 ,分析了我国土地利用中存在的主要问题 ,进一步提出了实施土地资源可持续利用的具体对策     

都匀阶地土的承载特性研究

分析了阶地的形成与土层序列阶地土的判属以及持力层和承载。     

Samples Selection for Artificial Neural Network Training in Preliminary Structural Design

An artificial neural network (ANN) is applied in the preliminary structural design of reticulated shells. Major efforts are made to enhance the generalization ability of networks through well-selected training samples. Number-theoretic methods (NTMs) are adopted to generate samples with low discrepancy, i.e.uniformly scattered in the domain, where discrepancy is a quantitative measurement of the uniformity. The discrepancy of the NTM-based sample set is 1/6-1/7 that of samples with equal spacing. In a case study,networks trained by NTM-based samples are compared with those trained by equal-spaced samples in generalizing performance. The results show that both the computational precision and stability of the former ANNs are more satisfactory than those of the latter. It is concluded that the flexibility of ANNs in generalizing can be effectively increased by use of uniformly distributed training samples rather than simply piling data.More reliable uniformity should be obtained, however, through NTMs instead of equal-spaced samples.     

武夷山市红壤资源开发利用评价

分析了武夷山市红壤是在中亚热带常绿阔叶林的生物环境影响下,经过明显的富铝化过程和旺盛的生物循环过程而发育形成的.并针对红壤瘦、酸、粘特性,生产力水平不高及水土流失与洪涝灾害的潜在威胁性等三个问题,提出通过健全、完善红壤资源管理体系,建设水土资源环境保护体系,增加投入、培肥土壤、提高产出及发展生态农业等措施以实现对红壤资源的合理开发利用.     

Forecasting recessions using the yield curve

We compare forecasts of recessions using four different specifications of the probit model: a time invariant conditionally independent version; a business cycle specific conditionally independent model; a time invariant probit with autocorrelated errors; and a business cycle specific probit with autocorrelated errors. The more sophisticated versions of the model take into account some of the potential underlying causes of the documented predictive instability of the yield curve. We find strong evidence in favour of the more sophisticated specification, which allows for multiple breakpoints across business cycles and autocorrelation. We also develop a new approach to the construction of real time forecasting of recession probabilities. Copyright © 2005 John Wiley & Sons, Ltd.     

沉管碎石桩处理软土地基的应用过程

沉管碎石桩是地基处理的方法之一,可以有效地提高地基承栽力,使沉降量减少,增加地基的稳定性,并且可以减少环境污染。对此方法的施工作了详细的介绍。     

高等级公路水泥稳定土施工工艺--博茨瓦纳帕塞公路水泥稳定层平地机施工技术研究

以博茨瓦纳帕塞公路工程施工为例，详细介绍了高等级公路水泥稳定土的施工准备、工艺流程与技术要求，指出了施工中应注意的问题。     

Impoverishment of Soil Nutrients in Gully Erosion Areas in Yuanmou Basin

The impoverishment of soil nutrients of nine gully head areas in Yuanmou Basin is assessed through an integrated evaluation method established on the basis of Fuzzy mathematics and multivariate mathematical theory. Results show that soil erosion of gully erosion area in Yuanmou basin has resulted in severe impoverishment of soil nutrients. All gully head areas are at high leves of impoverishment except for one at middle. By probing into and analyzing the mechanism of impoverishment of soil nutrients, we find that soil erosion has led to impoverishment of soil nutrients in a way of compacting soil, heightening position of obstacle horizon, and reducing the content of organic matter, as well as the direct loss of nutrient elements. Finally, this paper points out that soil and water conservation arming at the prevention of soil erosion is the most effective way against impoverishment of soil nutrients in Yuanmou basin.     

大型径向和推力滑动轴承试验台结构设计与应用

对径向滑动轴承、推力滑动轴承试验台以及实验台的结构设计、试验范围、功能和工业产品实验进行了介绍。该试验台在滑动轴承的实验研究中得到了很好的应用。     

系统结构模型分部的底层要素法

本文从系统的底层要素出发，提出并证明了底层要素存在性、底层要素后果集并集的完全性以及它们在同一部分的充分必要条件，由此导出了系统结构模型分部的算法，实际应用进一步说明了这一方法的有效性。