利用前线分子轨道能预测有机物生物毒性的方法

本文以线性自由能理论为基础提出了一种利用分子轨道能预测有机物生物毒性的方法，并利用这种方法建立了预测氯代芳烃化合物发光菌毒性的定量相关方程。     

A combination line transect and capture-recapture sampling model for multiple observers in aerial surveys

We present a robust sampling methodology to estimate population size using line transect and capture-recapture procedures for aerial surveys. Aerial surveys usually underestimate population density due to animals being missed. A combination of capture-recapture and line transect sampling methods with multiple observers allows violation of the assumption that all animals on the centreline are sighted from the air. We illustrate our method with an example of inanimate objects which shows evidence of failure of the assumption that all objects on the centreline have probability 1 of being detected. A simulation study is implemented to evaluate the performance of three variations of the Lincoln-Petersen estimator: the overall estimator, the stratified estimator, and the general stratified estimator based on the combined likelihood proposed in this paper. The stratified Lincoln-Petersen estimator based on the combined likelihood is found to be generally superior to the other estimators.     

污水处理厂内毒物归宿模型的参数估计及应用

在建立城市污水处理厂毒物归宿模型的基础上，继续探讨了固液相吸附分配系数Ｋｐ，生物降解速率系数Ｋｂ，挥发及吹脱速率系数ＫｖＫｓｔ等模型参数的估计方法，并就模型的检验，模拟及其在风险评价中的应用作了案例研究。     

农药降解方程y=ae~(-kt)参数估计的一种方法

农药降解方程ｙ＝ａｅ－ｋｔ参数估计的一种方法王增辉王蕴波窦森贾红震（吉林农业大学基础科学系，长春１３０１１８）关键词降解方程，参数估计．１前言在农药的降解规律研究中，一般都认为，农药在土壤中、植物上的消失，可用一级反应动力学公式来表示［１］，即在不考...     

冷挤压组合凹模的寿命估算

冷挤压组合凹模的失效主要是凹模内腔疲劳裂纹的出现,在模具设计的前期较为准确的估算出组合凹模的疲劳寿命是模具优化设计的前提。通过对组合凹模的应力分析后,采用Mises屈服准则的方法把凹模所受的多轴应力转化成单轴应力,再利用局部应力应变法找到了估算冷挤压组合凹模寿命的途径。     

长春市水环境生态系统服务功能价值评估

生态系统服务不是无偿提供的，而是用货币量算，价值不菲。对长春市水生态系统的5项服务功能进行估算累加。可以得出目前长春市水生态系统服务每年价值在62599．35万元之上。比1990年的水生态系统服务价值有所削减。也就是说，在过去10a间，长春市水生环境给人们提供的福利在减少。因为各技术和学科本身的局限，所得值只能作为决策者的参考，而更精确的结果需要更合理的方法和更深入广泛的研究。     

遗传模拟退火算法在水质模型参数估值中的应用研究

在传统遗传算法 (GeneticAlgorithms,GA)基础上引入模拟退火技术 (SimulatedAnnealing,SA) ,提出了遗传模拟退火算法 (GSA) ,并将其应用到水质模型参数估值中。计算结果表明 ,GSA法综合了 2种优化方法各自的优点 ,不但克服了传统GA容易早熟的缺点 ,还加强了算法的收敛速度 ,因而具有良好的优化性能。不同的参数估值方法比较进一步验证了新方法的有效性。GSA法在环境优化领域中将具有广阔的应用前景     

建立我国主要农作物卫星遥感估产运行系统的主要技术环节及解决途径

本文结合我国耕地和作物种植特点,并根据“八五”攻关实践,指出了建立我国主要农作物（小麦、玉米、水稻、棉花、大豆）卫星遥感估产运行系统所面临的主要技术环节,即系统的工程化总体设计；卫星遥感估产区划；背景数据库的建立；遥感信息同化技术；不同作物面积提取、长势监测与单产模型；运行系统的建立。进一步提出了系统实现的技术方案、步骤和解决这些主要技术环节的设想,即统一组织实施,避免重复工作；抓住主要农作物主产区遥感估产,以河南、安徽、江苏３省为多种作物综合卫星遥感估产试点省；结合遥感信息同化技术,建立面积提取、长势监测、单产模型体系和相应的软件模块；最终建立全国的卫星遥感估产集成系统。     

线性溶剂化能相关方法应用及参数估算

简要介绍了线性溶剂化能相关方法的原理，回顾了该方法在溶解度、辛醇／水分配系数和生物毒性预测中的成功应用，重点讨论了参数估算规则，以利于该方法进一步推广。     

Learning to predict channel stability using biogeomorphic features

Current human land use activities are altering many components of the river landscape, resulting in unstable channels. Instability may have serious negative consequences for water quality, aquatic and riparian habitat, and for river-related human infrastructure such as bridges and roads. Resource management agencies have developed rapid bioassessment surveys to help assess stability in a fast and cost-effective way. While this assessment can be done for a single site fairly rapidly, it is still time-consuming to apply over large watersheds and assessment activities must be prioritized. We constructed a system that employs commonly available map data as inputs to cost-sensitive variants of decision tree algorithms to predict the relative channel stability of different sites. In particular, we use bagged lazy option trees (LOTs) and bagged probability estimation trees (PETs) to identify all unstable channels while making the smallest number of errors of classifying stable channels as unstable, thereby minimizing cost and maximizing safety. We measured the performance of the classifiers using ROC curves and found that the PETs performed better than the LOTs in situations where the number of instances of the stable and unstable classes were relatively balanced, but the LOTs did better where unstable examples were relatively rare compared to stable, perhaps due to the LOTs’ ability to focus on individual examples.