电厂煤炭采样方法的分析与应用

电厂入厂煤煤质检测主要为商业结算提供依据，基于采样在检测环节中的重要性，以实例详细阐述了影响采样误差的因素及应对措施，重点探讨了皮带煤流机械化采样和煤堆采样方法的应用，指出了煤炭机械化采样的优越性和人工采样的必要性。     

自动采样机在精煤采样工作中的应用

为了降低工人的劳动强度，提高所采煤样的代表性，使所得精煤指标能更好的指导生产，自行设计了刮臂式采样机，在精煤采样工作中应用，取得良好效果。     

浅谈空气自动监测与人工采样监测的差异性

随着科技的发展，空气自动监测系统越来越广泛的运用到了环境监测中，但其监测的数据跟人工采样监测的数据发生了一些变化。本文将就这些差异进行探讨，以抛砖引玉，产生共鸣。     

液体采样泵智能控制系统

本控制系统适用于对化学分析检测设备采样泵的控制,当被监测液体的排出流量达到一定量时采样泵自动启动实施采样,排出流量小于一定量时采样泵自动停止采样,使检测设备的检测实现不排放不需检测,排放立即检测,从而提高对企业污染源排放检测的公平性,减少了设备损耗,节约电力能源。     

交流采样装置的构成原理和实现

随着电力系统的快速发展,交流采样测量装置的使用已越来越普及,交流采用测量装置作为电网电测量参数的在线测量仪器,具有较好的准确度和稳定度。本文首先分析了交流采样与直流采样的异同,然后重点介绍了交流采样的构成原理和实现,最后提出了一些在交流采样实现中的难点。     

浅析交流采样测量装置的选用与误差测试

目前,由于交流采样测量装置在电力系统中得到广泛的应用,就需要我们加强交流采样测量装置管理,以此规范校验方法,使国网公司组织有关专家编制完成了《交流采样测量装置校验规范》和《交流采样测量装置校验作业指导书》。根据国网公司[2005]347号文件精神,并根据目前交流采样测量装置的应用以及维护管理情况,我们分析了关于交流采样测量装置的测试方法、监督方法,并加以实施。下面是关于实施的相关内容。     

环境监测中大气采样技术研究

随着社会的逐渐发展,人们的环保意识逐渐增强,尤其是大气环境的监测力度呈现增长趋势。大气采样是环境监测的重要环节。在新时期,大气环境污染状态越来越复杂,对人们的身体健康造成不利影响,因此,需要进一步完善大气采样技术,才能保障大气采样的全面性,为提升监测结果的准确性提供保障。论文主要对环境监测中大气采样技术相关内容进行研究,旨在进一步提升大气环境监测效果,为大气环境治理工作的开展提供依据。     

影响环境监测现场采样质量的因素及对策

近些年来经济高速的发展带来了严重的环境问题,在这种背景下环境监测的重要性逐渐凸显,而采样水平的高低在很大程度上决定了环境监测工作的效果,因此,是否能够有效提高环境监测工作质量,现场采样质量高低至关重要,所以在实际现场采样过程当中尽可能的减少误差成为了绝大多数环境监测工作者所考虑的问题.现阶段仍然有一些因素的存在会对现场采样质量造成影响,本文正是在此基础上展开研究,通过分析影响环境监测现场采样质量的因素,进一步探讨解决问题的对策.     

交流采样装置现场校验方法之探讨

文章从目前交流采样装置现场校验方法出发，对交流采样测量设备现场校验技术进行探讨，推动交流采样装置实行规范化、科学化的维护和检修，提高电网的运行水平。     

谈化工产品采样的原则与要求

正确地采样(抽样),是精细化学品检验员所必须掌握地基本技能之一。如果采样方法不正确,即使分析工作做得非常仔细和正确,也是毫无意义的。我们在采样中应遵循的基本原则与要求,就是使采得的样品有充分的代表性。     

顶空气相色谱法测定pvc中的残留氯乙烯单体含量的探讨

测定pvc中的残留氯乙烯单体含量,国标GB/T 4615-2008中采用手动平衡和手动自顶空取样,此方法人为因素干扰多,试验结果重复性差,样品平衡温度不稳定,本文采用自动顶空进样器进样,压力平衡进样技术,使用全封闭传输系统,顶空样品在毛细管线中无扩散;顶空样品在进样过程中无载气稀释,很大程度减少了样品平衡条件的变化,免除了用水浴锅恒温的繁琐步骤。本文的顶空进样器采用压力平衡进样技术以保证得到窄的色谱峰形。可以提供更高的检测灵敏度和确保分析结果的重现性和准确性。     

The sieve method, a sampling method for audit practice

The sieve method is a new sampling method which may, under certain conditions, be validly used even though the statistical evaluation is based on random sampling. The method is described in both one-phase and multi-phase sampling schemes.     

科技文献中标点符号的正确用法

标点符号在科技工程界的书面语言中是十分重要的。为此，根据ＧＢ／Ｔ１５８３４－１９９５《标点符号用法》，结合工作经验，阐述了标点符号在科技文献中的正确用法     

General framework for the rotation of units in repeated survey sampling

Coordination of probabilistic samples is a challenging theoretical problem faced by statistical institutes. One of their aims is to obtain good estimates for each wave while spreading the response burden across the entire population. There is a collection of existing solutions that try to attend to these needs. These solutions, which were developed independently, are integrated in a general framework and their corresponding longitudinal designs are computed. The properties of these longitudinal designs are discussed. It is also noted that there is an antagonism between a good rotation and control over the cross-sectional sampling design. A compromise needs to be reached between the quality of the sample coordination, which appears to be optimal for a systematic longitudinal sampling design, and the freedom of choice of the cross-sectional design. In order to reach such a compromise, an algorithm that uses a new method of longitudinal sampling is proposed.     

抽检国标路线图

本文将16个抽检国标，主要基于计数与计量、孤立与连续的分类，归纳成便于检索的路线图。对类似抽检问题，比较了众多不同抽检国标的方案，并举例说明百分比抽检不合理。     

双侧限“σ”法抽样方案的设计（均值）——关于GB／T8054—2008表2的设计建议

文章利用文献[1]中的理论公式和数据表，给出了以均值为质量指标的双侧限“σ”法抽样方案表。该抽样方案表的设计是对GB／T8054—2008表2的改进，不仅符合设计目标，而且更便于应用。     

Uncertainty Estimation for Pseudo‐Bayesian Inference Under Complex Sampling

Social and economic studies are often implemented as complex survey designs. For example, multistage, unequal probability sampling designs utilised by federal statistical agencies are typically constructed to maximise the efficiency of the target domain level estimator (e.g. indexed by geographic area) within cost constraints for survey administration. Such designs may induce dependence between the sampled units; for example, with employment of a sampling step that selects geographically indexed clusters of units. A sampling‐weighted pseudo‐posterior distribution may be used to estimate the population model on the observed sample. The dependence induced between coclustered units inflates the scale of the resulting pseudo‐posterior covariance matrix that has been shown to induce under coverage of the credibility sets. By bridging results across Bayesian model misspecification and survey sampling, we demonstrate that the scale and shape of the asymptotic distributions are different between each of the pseudo‐maximum likelihood estimate (MLE), the pseudo‐posterior and the MLE under simple random sampling. Through insights from survey‐sampling variance estimation and recent advances in computational methods, we devise a correction applied as a simple and fast postprocessing step to Markov chain Monte Carlo draws of the pseudo‐posterior distribution. This adjustment projects the pseudo‐posterior covariance matrix such that the nominal coverage is approximately achieved. We make an application to the National Survey on Drug Use and Health as a motivating example and we demonstrate the efficacy of our scale and shape projection procedure on synthetic data on several common archetypes of survey designs.     

Estimation of the mean in ranked set sampling with non responses

The estimation of the population mean when ranked set sampling [rss] is used for selecting the sample and non responses [nr] are present, is studied. The nr stratum is sub sampled using simple random sampling with replacement. Two strategies are analyzed. One of them is based on the selection of a sub sample from the nr in each cycle. The other uses sub samples selected among the nr in each rank.  The accuracy of the proposed estimators is characterized by the corresponding expected variances. Simulations and real life data are used for analyzing the behavior of them. Acknowledgements: This paper was developed partially during the visit of the author to Université des Antilles et Gouyane. The author gratefully acknowledges the helpful suggestions of the referees and thanks the support of DAAD for visiting Humboldt University where a version of the paper version was made.     

Mixed random systematic sampling designs

In this paper, an alternative sampling procedure that is a mixture of simple random sampling and systematic sampling is proposed. It results in uniform inclusion probabilities for all individual units and positive inclusion probabilities for all pairs of units. As a result, the proposed sampling procedure enables us to estimate the population mean unbiasedly using the ordinary sample mean, and to provide an unbiased estimator of its sampling variance. It is also found that the suggested sampling procedure performs well especially when the size of simple random sample is small. Received August 2001     

连续批计数抽样检验中的跳批抽样技术

文章介绍了跳批抽样的基本原理、适用范围、条件以及一般程序。文章主要对GB／T2828．3《计数抽样检验程序第3部分跳批抽样程序》技术内容进行了解读和介绍,帮助实际应用者正确运用跳批抽样程序,以达到预期目的。