排序计算方法初析

排序是数据处理中经常使用的一种重要操作。在介绍常用排序计算方法的同时，经过实践分析，提出分区排序的计算方法及合适的分区数，排序速度有很大的提高。     

大坝混凝土浇筑块排序方法的评价研究

大坝混凝土浇筑块的排序方法影响其浇筑施工进度和施工强度的均衡性。本文基于相同的混凝土施工方案下用不同浇筑块排序方法对大坝浇筑过程进行仿真的结果，提出了浇筑块排序方法优劣的评价指标，并采用熵权与决策者的主观权重相结合的方法，建立了不同排序方法的评价模型，较好的解决了各种排序方法的评价和选择问题。     

电力系统在线安全分析偶然事故排序方法的改进

考虑到系统元件发生故障的不确定性，把对偶然事故排序中通常采用的系统行为指标（performance index）同系统状态概率相结合，形成偶然事故对系统影响的期望值，以此对偶然事故进行排序，使得对偶然事故的选择更具有合理性。分别对IEEE-RTS 24母线和73母线系统进行试算，说明考虑事故发生概率对偶发事故进行排序选择是很有必要的。     

方框1 坝址的社会和环境排序

方框１坝址的社会和环境排序装机：移民和装机：淹没土地这２个比值用来初步排序，对大多数坝址来说是足够可靠的。第２步近似评价时，如果需要，可将这２个比值进一步细分为５个指标进行排序。然后再进行更详细的部门环境评价。社会排序（１）移民人数按装机容量与移民人...     

层次分析法在承包工程项目风险评价中的应用研究

把层次分析法（AHP）运用于工程项目风险评价，建立层次结构模型，可实现工程单个风险因素的重要性排序，系统总体风险度的评价以及风险应对方案的选择，并通过工程项目实例进行风险因素重要性排序的应用。     

相对贴近度法运用于岩石质量排序

选取同类岩石的几个试验指标，作为岩石综合排序的依据，采用相对近度法计算了其综合排序，给出了同类岩石的质量优劣顺序。通过与岩石分级结果比较可以发展，分级方法能给出岩石质量具体属于哪一级，但在分级结果基本相同或差距不大的情况下，究竟孰优孰劣，相对贴近度法排以了则能具体给出其前后质量顺序，这就可以说明排序方法作为分级方法的补充动用岩石质量评价中，具有一定的理论意义和实和意义。排序方法可适用于不同类岩石的     

超高压大系统最优恢复计划的多目标模糊决策法

多层动态规划决策方法有效地解决了超高压大系统恢复计划决策问题，而其中分层优化方法涉及到对多个对象按照多因素排序、分类和以多项目标选择最佳决策方案的问题，这种综合排序及综合决策问题不易用经典方法来解决。为此，提出超高压大系统恢复计划决策的多因素模糊综合排序和分类方法，以及多目标模糊综合决策方法，较好地解决了该问题。仿真结果表明该方法科学、有效。     

辽西山地丘陵区小流域土壤水分空间变异特性研究

为揭示地形条件和用地类型土壤含水率影响因素及其变异特性，以辽西山地丘陵区下山口小流域为例，用统计学方法全面探讨土壤水分变异特性。结果表明：从低到高不同土地利用方式下土壤含水率排序：灌木林地<林地<草地<耕地，各用地类型呈极显著差异，从土壤剖面上含水率表现出先下降后上升变化特征；从低到高不同地形条件下土壤含水率排序：坡顶<坡地<沟底<梯田，不同坡位上排序：坡中<坡上<坡下，不同坡向上排序：阳坡<阴坡，土壤含水率达到中等变异程度。研究成果为辽西山地丘陵区不同地形条件下植被布局、土地利用结构优化以及土壤水分管理提供一定支持。     

一种有效的事故排序方法

本文讨论了利用伴随网络法进行事故排序的基本原理和方法；并列出各种方法与直流法相比 的误差；提出一种改进的排序方法，包括公式推导，试算结果及误差分析。     

数据库同一记录各字段值的排序

提出数据库同一记录不同字段排序的问题，并指出可利用跳跃式冒泡排序来实现，并简要分析了跳跃式冒泡排序的基本思想，通过一实例－开放实验数据管理系统，讨论了如何实现对数据库同一记录的各个字段值排序。     

地下厂房施工过程的三维非线性数值模拟分析

根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。     

广西钦江流域水沙年际变化规律分析

为了探究河流水沙的变化规律及影响因素,利用钦江陆屋流域1957—2016年的长时序年降水量、年径流量和年输沙率数据,采用5年滑动平均法、R/S检验法、Mann-Kendall突变检验法、累积距平法及复Morlet小波分析法分析以上序列的趋势性、突变性和周期性;运用双累积曲线法分析降水和径流输沙关系的变化;最后结合流域森林转型特征来进行分析。结果表明:(1)降水量弱上升、径流量减少、输沙率显著减少,在α=0.05和β=0.01的显著水平下,降水量和径流量无变异,输沙率弱变异。降水量在1962年、1971年、1989年和2013年发生突变,径流量在1963年、1971年、1989年和2007年发生突变,输沙率在1967年、1971年、1981年和2001年发生突变。降水量存在4类时间尺度,23 a、13 a分别为第一、二主周期;径流量序列存在3类时间尺度,14 a、9 a分别为第一、二主周期;输沙率序列存在4类时间尺度,22 a、5 a分别为第一、二主周期。(2)降水量-径流量累积关系分为两个阶段,即1957—1988年和1989—2016年,斜率分别为0.006 8、0.005 8;降水量-输沙量累积关系分为四个阶段:1957—1962年、1963—1988年、1989—1998年和1999—2016年,斜率分别为0.014、0.019 4、0.016 4、0.009,造成水沙关系变化的原因是人类活动的影响。(3)广西林业建设和森林转型的发展过程是径流量和输沙量不断发生变化的原因。     

Evaluation of freshwater mussel relocation as a conservation and management strategy

The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects.     

Toxic effect of the mosquito killer, S-Deltamethrine, on the development and respiratory electron transport system activity of the embryos of bream (Abramis brama L.), roach (Rutilus rutilus), barbell (Barbus barbus) and pike (Esox lucius)

The effect of the insecticide, S-Deltamethrine (DM, LC₅₀ for mosquito larvae: 0.02 ppb), in the concentration range between 0.025 and 2500 ppb was examined in both embryogenesis and embryonic evolution of the electron transport system (ETS) of the bream, roach, barbel and pike. A 0.025 ppb concentration of DM caused 10-25% death of the embryos in the first 2 days of incubation. Fifty per cent of the roach embryos died by the end of a 144 h incubation period when the concentration was 0.025 ppb. In 2.5 ppb, 50% of the embryos died after 120 h. In 25 ppb, 50% death was registered after 96 h, and in 250 and 2500 ppb, 50% death was detected after 48 h. Fifty per cent of the barbel embryos died after a 48 h long incubation time in 250 and 2500 ppb. The same mortality was detected for the embryos of pike in 2500 ppb after a longer (148 and 168 h) incubation time. Half of the bream embryos died after 24 and 48 h at a concentration of 2500 ppb. Larvae showed a more sensitive response to treatments than did embryos. After hatching, 30-84% of the larvae died in 0.025 ppb. Compared to embryos, larvae moved less in a concentration of 0.025 ppb and could not swim as easily as controls. In a concentration >0.25-2.5 ppb, larvae were passive and often malformed. S-Deltamethrine inhibited ETS activity in a concentration-dependent manner. Electron transport system activity of larvae was reduced by 50% in 250 ppb concentration.     

浅谈优化Vray渲染在制作三维场景的应用研究

用Vray三维渲染引擎来渲染三维场景,其质量和速度是由一些影响因素和参数设置决定的,不同的参数和因素,可以得出不同的三维渲染效果.因此,分析、优化三维渲染质量和速度的影响因素,正确、合理的选择参数对提高Vray最后渲染阶段的质量和速度非常重要.     

温排水对陡河水库富营养化影响的预测研究

研究电厂温排水对陡河水库富营养化的影响。陡河水库属我国北方地区多功能浅水型水库 ,已运行 4 0余年。库区水情较复杂 ,热影响严重 ,营养盐偏重 ,具有一定的典型意义 ,可供类似湖库研究热影响问题参考。全文分三篇刊登 :1.陡河水库热影响与富营养化调查及生物学评价 ;2 .温排水对陡河水库富营养化影响的预测研究 ;3.陡河水库富营养化趋势分析与防治对策     

The role of riparian vegetation and woody debris in the development of macroinvertebrate assemblages in streams

Riparian vegetation development and macroinvertebrate assemblages were studied in 16 streams formed between 35 and 230 years ago, following glacial recession in Glacier Bay National Park, southeast Alaska. Riparian vegetation established most rapidly in streams where flow variation in downstream reaches was buffered by a lake. Riparian vegetation development was positively correlated with lower bank stability, but was independent of stream age. Roots and branches of riparian vegetation trailing into streams (trailing riparian habitat—TRH) were shown to be an important habitat for a number of macroinvertebrate taxa. In young and unstable streams, TRH was colonized mainly by Plecoptera whereas in more stable lake‐influenced streams Simuliidae dominated. Significant coarse woody debris (CWD) accumulations were not observed until after approximately 130 years of stream development had occurred when certain channel features, such as gravel bars, were stabilized by dead wood. Where dead wood was present, opportunistic wood taxa were abundant, even in the younger streams. However, a xylophagous species, Polypedilum fallax, was not recorded until streams were over 100 years old. Two‐way indicator species analysis (TWINSPAN) using presence/absence of macroinvertebrate taxa on TRH, initially divided streams into lake and non‐lake systems, but subsequent divisions were consistent with differences in stream age. TWINSPAN of macroinvertebrate assemblages on dead wood again highlighted differences in stream age. Canonical correspondence analysis indicated that bed stability and stream age were the most important environmental variables influencing macroinvertebrate distribution on TRH. Trailing riparian habitat was most abundant in moderately unstable streams where it facilitates invertebrate colonization. CWD contributes markedly to channel stabilization, provides habitat for invertebrate xylophages, and confers additional habitat complexity. Maximum levels of CWD are predicted to occur in non‐lake streams after approximately 300 years, but at least a further 100 years will be required in stable streams below lakes where dead wood entrainment is not enhanced by flooding, channel migration and bank undercutting. A conceptual model summarizing the role of TRH and CWD on stream development in Glacier Bay is presented. Copyright © 2005 John Wiley & Sons, Ltd.     

软土卸荷强度试验方法探讨及试验研究

通过不同固结、剪切路径,对广州典型软土进行了卸荷抗剪强度试验,试验结果显示,不同的试验方法得到不同抗剪强度参数。不同试验方式下,土样卸荷后的抗剪强度指标都低于加荷下的抗剪强度指标;对基坑工程而言,采用DCU（侧向卸荷三轴试验）更符合实际情况,鉴于该试验方法较难,可采用DGK（先预压固结后卸荷至不同固结压力再进行快剪试验）得到的指标来代替。试验结果还表明：卸荷状态下土体应力应变曲线仍为双曲线形式,且曲线为加工硬化型;在相同的围压下,卸荷强度小于加荷强度;初始切线卸荷模量小于初始切线加荷模量,即用加荷下的加荷模量来代替卸荷下的卸荷模量将会使得工程偏于危险。     

Catchment‐scale controls on groundwater–surface water interactions in the hyporheic zone: implications for salmon embryo survival

The spatial and temporal variability of groundwater–surface water (GW–SW) interactions in the hyporheic zone were investigated in a semi‐pristine upland salmon spawning catchment (Girnock Burn) in the Cairngorm Mountains, northeast Scotland. Stream and hyporheic water quality (200–300 mm depth) were monitored fortnightly at 16 spawning locations distributed throughout the catchment. Hydrochemical tracers were used to assess local GW–SW interactions. Stratified streambed incubators (50–300 mm) provided information on salmon embryo mortality at a sub‐set of ten locations. Hyporheic water quality varied both temporally and spatially according to local GW–SW interactions. It was possible to categorize sites into three broad typologies reflecting local stream–aquifer interactions: (1) groundwater‐dominated; (2) surface water‐dominated; and (3) sites exhibiting transient water table features. Groundwater upwelling occurred in areas where low permeability glacial moraine features caused substantive valley constriction. These locations were also conducive to accumulation of spawning grade gravels and consequently were utilized heavily by spawning salmon. Long residence groundwater was typically characterized by low dissolved oxygen (DO), of sufficiently low quality to be detrimental to salmon embryo survival. At sites dominated by surface water, hyporheic DO remained high throughout and rates of embryo survival were correspondingly high. Survival rates were also high at sites where hydrochemical characteristics indicated a transient water table. This is probably attributable to the hydrological conditions which resulted in increasing DO concentrations towards hatch time when embryo oxygen demand is at its maximum. The degree to which the findings of this study are directly applicable to other catchments is currently unknown. However, similar effects have been observed elsewhere, and based on the information presented here, there are clear implications for fisheries managers who may wish to consider the use of surface incubation facilities to negate the effects of low DO groundwater upwelling where it dominates available spawning habitat. It is suggested that future research should aim to integrate across spatial scales and disciplines to obtain a better understanding of the ways in which hillslope and riparian zone hydrology affect GW–SW interactions, hyporheic zone processes and stream ecology. © Crown copyright 2005. Reproduced with the permission of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd.     

Pesticide residues in Volta Lake, Ghana

The Volta River basin comprises ≈ 70% of mainland Ghana, being inhabited by a majority of the country's population. The purpose of this study was to analyse water and sediment samples at six locations in Volta Lake for residues of persistent organochlorine pesticides. Residues were extracted by use of two types of extractions, including a standardized solid phase extraction procedure for water samples and a Soxhlet extraction procedure for sediment samples. All samples were analysed by gas chromatography. Lindane and endosulfan were identified in concentrations ≤ 0.008 p.p.b. and 0.036 p.p.b., respectively, in water, and ≤ 2.3 p.p.b. and 0.36 p.p.b., respectively, in sediments. Dichlorodiphenyltrichloroethane and dichlorodiphenyldichloroethylene were also found in sediment samples (in concentrations ≤ 9.0 p.p.b. and 52.3 p.p.b., respectively). No significant contamination was noted in the lake. The distribution of pesticide residues in water and neighbouring sediment are briefly discussed. Different bioconcentration factors obtained in this study allowed the confirmation of the complex processes already reported in the literature regarding the partitioning of chemicals between sediment and water.