查询词典 stratified sampling

By the introduction of the theory of sampling constant presented by Ingamells and Switzer, the stratified sampling for segregated bulk materials were studied.

将Ingamells-Switzer取样常数理论引入分层性固体物质的取样研究，提出了分层取样的最优化设计方案，推导出了各层取样量及分层取样方差极小值计算公式。

We made use of the methods of stratified sampling and random sampling to investigate 269 882 broth prescriptions of Medical Department of TCM in 21 various hospitals, 18 provinces, and constructed the database, then applied Weka KDD software to analyze.

在全国不同区域，选取18个省市的21家医院，采用分层抽样和简单随机抽样相结合的方法，收集门诊中医内科内服汤剂处方269 882张，构建中药饮片用量数据库，基于Weka数据挖掘软件进行统计分析。

This paper discusses cluster sampling and stratified cluster sampling in continuous surveys with censuses.

本文讨论了连续调查中应用普查方法时的整群抽样和分层整群抽样。

This paper studies a fuzzy norm and its stratified properties. The completeness and separability of stratified space of fuzzy normed space are discussed.

摘要研究一类模糊范数及其层次结构性质，对模糊赋范空间的层次空间的完备性、分离性等性质进行了讨论。

Therelationship between the turbulent kinetic energy and its dissipation rate,whichis widely used to parameterize the dissipation rate in turbulence closure models,is found to hold well for both reversing and rotating flows,but with differentcoefficients.Microstructure profiling measurements at two comparative stations (a deepercentral basin and a local shelf break) in the stratified Yellow Sea are analyzed,with emphasis on tidal and internal-wave induced turbulence near the bottomand in the pyenocline.The water column has a distinct three-layer thermohaline structure,consisting of weakly stratified surface and bottom boundary layers anda narrow sharp pycnocline.Turbulence in the surface layer is controlled by thediurnal cycle of buoyancy flux and wind forcing at the sea surface.while thebottom stress induced by barotropic tidal eurrents dominates turbulence in thebottom boundary layer.The maximum level at which the tidally enhanced mixingcan affect generally depends on the magnitude of the tidal current,and it canbe up to 10-15 m in the Yellow Sea.This suggests that,in the deeper regionsof the shelf seas,turbulent dissipation and mixing are very weak at the levelsbetween the near-bottom tidally enhanced layer and the pycnocline.Therefore,these levels provide a significant bottle neck for the vertical exchanges.In theshallow regions,however,the tidally-induced turbulence can occupy the wholewater colum below the pycnocline.A quarter-diurnal periodicities of the turbulentdissipation rate and eddy diffusivity are found at different heights with evidenttime lag.In the relatively flat central basin,the pycnocline is essentially non-turbulent and internal-wave activity is very weak.Therefore,vertical fluxes acrossthe pycnocline decreased to molecular levels.In contrast,internal waves of variousperiods can be always found near the local shelf break.

对强层化季节黄海两对比性站位(分别位于中央海盆区与局地陆坡区)处层化、内波以及湍流混合特征的研究结果表明：1、强层化季节的陆架海水体一般呈现显著的三层热盐结构，在水体近乎混合均匀的上混合层与潮流底边界层之间为强跃层；2、近表层水体的湍流混合强度主要由海表浮力通量的日变化与海表风强迫控制，而在潮流底边界层内，潮混合是水体热量、物质、动量与能量垂直交换的主要机制；3、潮混合影响的深度由潮流大小决定，在黄海，一般可达10-15 m，因此，在水深较深的区域，在跃层与潮混合所至深度范围的上界之间存在湍流混合非常弱的区域，这显著抑制水体内物质的垂直通量，为物质垂直交换的瓶颈，而在水深较浅的区域，潮混合影响范围可至跃层底部，因此物质在跃层以下整个水体中混合非常均匀，当跃层内间歇性强混合发生时，可以产生显著的跨跃层物质输运；4、近底潮致强湍流耗散缓慢地向上传播，底上不同深度处垂直湍扩散系数也具有显著的位相差异，且二者均随时间呈现四分之一周日周期的变化；5、在地形较为平坦的中央海盆区，内波活动非常微弱，因此跃层内湍流混合非常弱，垂直扩散系数为分子扩散水平，跨跃层物质通量受到显著抑制，而在地形变化较为显著的局地陆坡区，内波活动非常活跃，除内潮的影响外，高频内波与内孤立波的影响也很显著，因此跃层内存在很强的间歇性强混合，内孤立波存在的区域，水体湍流混合显著增强。

Through pure research into stratified terrestrial stress, it is gotten the stratified earth stress calculation model, and further research determines the basic procedure and method on earth stress delaminating.

通过分层地应力计算的理论研究，得出了地应力分层计算模式，并对地应力分层进行了研究，确定了地应力分层的基本步骤和方法。

The gas flowrate decreasing is associated with the pressure undershoot and temporary stratified flow. The magnitude of pressure undershoots and stratified period are sensitive to the magnitude of gas flowrate change and the distance away from the entrance of pipeline.

气量降低过程会有压力&过降&和短暂分层流型的出现，压力&过降&值和短暂分层流周期的大小除与气体的降低量有关外，还与测压点距管道入口的距离有关。

By timely and spatially controlling the physical and chemical characteristics of the fuel at both port injection stage and in-cylinder direct injection stage, HCCI/DI stratified compound combustion is developed to combine the advantages of HCCI and conventional DICI on cycle-to-cycle basis and achieve clean and efficient combustion at full load ranges without misfiring and knocking.Firstly, three types of dual fuel including n-heptane/diesel, iso-octane/diesel and ethanol/bio-diesel a...更多re utilized to investigate the combustion and emission characteristics of HCCI/DI stratified compound combustion. The experimental results indicate that n-heptane/diesel HCCI/DI combustion presents a three-stage heat release consisting of HCCI low temperature heat release, high temperature heat release and diesel diffusive combustion.

本文提出的基于燃料设计与管理的HCCI/DI分层复合燃烧是一种将HCCI燃烧和传统缸内直喷压燃融为一体的新型燃烧方式，通过对燃料理化特性的设计和在预喷与直喷阶段从时间尺度和空间尺度上对均质和非均质混合气制备过程的控制和管理，在发动机的一个工作循环中将均质混合气的HCCI燃烧和非均质混合气的DICI扩散燃烧相融合，彻底消除了HCCI燃烧在小负荷失火和大负荷爆震的弊病，实现了发动机全负荷范围内的高效清洁燃烧。

After the symbol-class accumulation average of every sampling point in all period of time, one time or above symbol-class accumulation average are set on every sampling point in every period of time in multi path searching window, and the result of calculation of all sampling points is stored.

完成所有时段中每个采样点的符号级累加平均运算后，对多径搜索窗口内每个采样点在时间轴上做一次或一次以上的符号级累加平均，并存储所有采样点的计算结果。

Common buckwheat ( F. esculentum ) is an allogamy crop, which is heterogony. There is heterogeneity in the species. To reveal the genetic diversity within cultivar population, In order to explore the sampling strategy that can reveal genetic diversity of buckwheat resources on the molecular level. PCR with intron-splice junction primers and long random primers was employed to reveal the genetic diversity within nine common buckwheat varieties and one tartary buckwheat cultivar population among different individuals. We established the sampling strategy in its genetic diversity study. Then we used the established sampling strategy, and the same PCR markers technique,to analysis the genetic diversity of 86 common buckwheat resources, the main results are as follows

甜荞是花柱异长自交不亲和的异花授粉作物，品种内存在一定的异质性，为了准确揭示甜荞遗传资源的遗传多样性，本研究采用因子分析法对86份甜荞遗传资源农艺性状数据进行分析；采用长随机引物和内含子切接点引物的PCR分子标记技术，对9个甜荞品种和1个苦荞品种不同个体间的遗传多样性进行了分析，建立了甜荞资源遗传多样性研究的取样策略；并利用建立的取样策略，采用PCR标记技术，对这86份甜荞资源的遗传多样性进行了分析，取得如下主要结果

Aquatic or marsh-growing fern allies; known to have existed since the Cenozoic; sometimes included in Lycopodiales.

生活于水中或湿地的蕨类；从新生代生存至今；有时归于石松目之中。

The engine was uprated from a 90hp Franklin to a 125hp Lycoming.

改良过的引擎是从90hp到125hp莱康明富兰克林。