贵州省土壤中天然放射性核素含量调查

本文报告贵州省土壤中天然放射性核素含量调查结果。全省共采集318个土壤样品,样品中核素的测定采用放化分析方法。结果表明,贵州省土壤中天然放射性核素含量,按各类土壤面积加权平均值为:~(238)U,45.6Bq·kg~(-1)(范围3.2—123.1Bq·kg~(-1));~(232)Th,41.3Bq·kg~(-1)(8.3—88.0Bq·kg~(-1));~(226)Ra,71.4Bq·kg~(-1)(3.7—226.1Bq·kg~(-1));(~(40)K,350.0Bq·kg~(-1)(23.7—802.6Bq·Kg~(-1)),属正常水平。     

What people do when they say they are conserving electricity

Econometric practitioners must always make the case that existing data may be used to forecast future responses to price changes. In residential electricity markets this means providing assurances that either territories with different prices are similar enough to be used as a guide, or that households are still able to react to price changes with the same conservation measures they have in the past. This article presents the results of a conservation behavior survey conducted both concurrent with and immediately after the last California electricity crisis in 2000–2001. The survey used open-ended questions that provide some assurance that there are still conservation behaviors that may be performed, as well as raw data that may be used to construct new closed-ended questions. The prevalence of conservation behaviors is modeled with a forgetfulness process, necessary when using data from open-ended questions, and implemented with a generalized method of moments (GMM) estimator.     

大型油罐软弱地基充水预压加固试验沉降监测

结合很多工程项目的实践经验，对大型油罐软弱地基充水预压加固试验的沉降监测作专题简述。分析了软弱地基、大型油罐给沉降监测带来的特定条件；阐述了其所表现的主要特点；介绍了所采取的有针对性的有关措施。并提出所采用的精度指标确定方法。     

Biclustering in data mining

Biclustering consists in simultaneous partitioning of the set of samples and the set of their attributes (features) into subsets (classes). Samples and features classified together are supposed to have a high relevance to each other. In this paper we review the most widely used and successful biclustering techniques and their related applications. This survey is written from a theoretical viewpoint emphasizing mathematical concepts that can be met in existing biclustering techniques.     

内蒙古自治区土壤中天然放射性核素含量调查

本文报道内蒙古自治区土壤中天然放射性核素含量的调查方法和结果。全区共采集668个土壤样品,其中25×25 km 网格点样品334个。测量采用γ能谱法。调查结果表明,内蒙古自治区土壤中天然放射性核素含量按面积和样品数加权的均值分别为:~(238)U,29.76和28.60 Bq·kg~(-1);~(232)Th,33.42和34.89 Bq·kg~(-1);~(226)Ra,27.49和26.95Bq·kg~(-1);~(40)K,655.56和624.63 Bq·kg~(-1)。     

Applications of extensive survey techniques to describe freshwater pearl mussel distribution and macrohabitat in the River Spey,Scotland

The spatial distribution and associated physical habitat of endangered freshwater pearl mussels (Margaritifera margaritifera) in a 145 km stretch of the River Spey, northeast Scotland, were investigated. The overall size of the Spey M. margaritifera population was estimated to be in the order of 10 million. Mussel distributions were compared with River Corridor Survey (RCS) macrohabitat data and found to be positively associated with coarse riverbed substrata, ‘fast‐flowing’ waters, riparian woodland, and river bends; and negatively associated with shingle bars, flood barriers, ‘slow‐flowing’ waters, eroding cliffs and aquatic macrophytes. Significant positive relationships between mussel density and channel slope, width and bank height, were also observed. Binary logistic regression models (based on four to six features) were used to predict the presence/absence of mussels or the occurrence of ‘optimal’ mussel habitat (i.e. mussel density >1 m^?2) at any given site. Overall predictive success rates of 79% and 78% were achieved, respectively. Discriminant function models (based on five variables) were also used, with predictive success rates of 78% and 88%, respectively. Copyright © 2004 John Wiley & Sons, Ltd.     

第二台南极巡天望远镜镜筒的结构设计及模态分析

镜筒是望远镜的基本组成部分,为了能够更好的满足望远镜成像质量的要求,需要对望远镜的镜筒机械结构进行研究。南极巡天望远镜由于其特殊的地理位置及气候、温度条件限制,与普通的望远镜在镜筒上有不同的要求。首先介绍了第二台南极巡天望远镜的光学设计参数及方案,并根据南极的特殊性设计了镜筒的机械结构。其次,通过有限元的分析方法,对望远镜镜筒的等弯沉量、主镜的面形变化进行了分析和计算,使其在工作状态时能满足光学设计的要求,第三,通过模态分析,分析了镜筒的刚度,使其满足电控系统的控制要求,最后通过锤击实验对镜筒的自振频率做了检验检测。经过实验分析,第二台南极巡天望远镜的镜筒能够满足光学的设计要求。     

土地利用调查数据库年度更新典型问题探讨

为准确掌握每年土地利用实际变化情况,保持土地调查数据的现势性,充分发挥土地管理参与国民经济的宏观调控作用,需对调查数据库进行更新。文章对数据库更新过程中的一系列典型问题进行探讨,在充分考虑数据库标准的基础上,对某些存在逻辑一致性、完整性、属性正确性的数据质量问题提出了详细的解决方案,这样既保证更新数据的合理性也保证下一年度土地利用数据库的准确性。     

精密单点定位技术在像控测量中的应用

介绍了精密单点定位技术的原理,对精密单点定位技术进行了精度分析。从生产部门的实用性出发,介绍了该技术在像片控制测量中的应用。     

测边网近似坐标电算方法的探讨

在测边网中,以测站为基础按顺时针方向组织边长观测数据,解决了未知点近似坐标计算时存在二义性的问题．提出了一种适合于编程计算近似坐标的算法,只输入必要的已知数据和观测值,不需要人工干预就能自动、高效、正确地计算出测边网中所有未知点的近似坐标。