改性粉煤灰处理高铁高锰酸性矿井水资源化研究

治理酸性矿井水是矿山环境保护的重要内容,粉煤灰以其独有的特性对酸性矿井水有一定的处理效果.粉煤灰处理酸性高铁高锰矿井水是实现资源化利用的关键途径,同时可以达到以度治废的效果.该文利用GENESIS XM260SX-射线能谱仪(EDS)分析粉煤灰化学组分,通过NaOH、CaO、Na2CO3、NaCl、HCl、H2SO4等改性剂改性粉煤灰,以此来提高粉煤灰对酸性矿井水的处理性能,实验确定Na2CO3为最佳改性剂,出水水质达到并优于GB50335-2002《污水再生利用工程设计规范》水质指标.     

一类2个相同部件并联可修系统非零初始状态解的研究

从生产实践出发修改了系统的初始条件,推证出系统非负解的存在唯一性。     

小麦产量性状与品质性状的对应分析及偏相关分析

运用对应分析和偏相关分析对河南省2006-2007年小麦品种区试高肥冬水组连续参试两年共19个品种的12个产量和品质性状进行了分析。对应分析结果将供试品种分为三大类,第一类包括9个品种,属高产中质类品种;第二类含2个品种,属中产中质类品种;第三类包括8个品种,属中低产、中上质品种。并对各类品种的改良目标进行了讨论。从产量、产量性状及品质性状的偏相关分析结果得知,增加穗粒数、千粒质量与密度是获致小麦高产优质的有效途径。图1,表5,参8。     

电子元器件学习论述

文章阐述了在教学和实践中掌握学习电子元器件的方法可从电子元器件的识别、元器件的工作特性以及元器件的检测方面入手。     

Forecasting US employment growth using forecast combining methods

We examine different approaches to forecasting monthly US employment growth in the presence of many potentially relevant predictors. We first generate simulated out‐of‐sample forecasts of US employment growth at multiple horizons using individual autoregressive distributed lag (ARDL) models based on 30 potential predictors. We then consider different methods from the extant literature for combining the forecasts generated by the individual ARDL models. Using the mean square forecast error (MSFE) metric, we investigate the performance of the forecast combining methods over the last decade, as well as five periods centered on the last five US recessions. Overall, our results show that a number of combining methods outperform a benchmark autoregressive model. Combining methods based on principal components exhibit the best overall performance, while methods based on simple averaging, clusters, and discount MSFE also perform well. On a cautionary note, some combining methods, such as those based on ordinary least squares, often perform quite poorly. Copyright © 2008 John Wiley & Sons, Ltd.     

基于NF-QFD的构件选择方法

在利用构件进行软件开发时,用户的需求通常是模糊和不确定的.提出了基于非线性模糊质量功能展开(NF-QFD)的构件选择模型.该模型在考虑构件之间高内聚、低耦合的同时还兼顾用户需求最大化,通过该模型可以解决软件系统开发时构件选择的优化问题,为设计人员提供更多的决策支持.     

Prediction in an Unbalanced Nested Error Components Panel Data Model

This paper derives the best linear unbiased predictor for an unbalanced nested error components panel data model. This predictor is useful in many econometric applications that are usually based on unbalanced panel data and have a nested (hierarchical) structure. Examples include predicting student performance in a class in a school, or house prices in a neighborhood in a county or a state. Using Monte Carlo simulations, we show that this predictor is better in root mean square error performance than the usual fixed‐ or random‐effects predictors ignoring the nested structure of the data. This is applied to forecasting the productivity of public capital in the private sector using nested panel data of 48 contiguous American states. Copyright © 2013 John Wiley & Sons, Ltd.     

是独立成分还是独立语

目前通用的《现代汉语》教材对于句子的特殊成分的看法从称呼上看不一致,有的叫“独立成分“,有的叫“独立语“,从概念所包含的实质内容上看也略有出入。     

论应力状态理论

借助数学工具解决弹性力学的基本问题，在弹性力学基本假定下详细解释什么是应力，其中包括应力的基本概念、如何描述一点处的应力状态及应力球张量与应力偏张量的基本内涵，并给出了定解问题所必须的边界条件，以及转轴作用下的应力转换方法和应力张量与应力偏量．     

常用低压电器元件的简介、选用与维修

低压电器是电气控制中的基本组成元件,对常用电器元件工作原理的了解有利于工程自动化的完成,并且也有利于电器维修。