Home OALib Journal OALib PrePrints Submit Ranking News My Lib FAQ About Us Follow Us+
 Title Keywords Abstract Author All

Publish in OALib Journal

ISSN: 2333-9721

APC: Only \$99

Submit

2019 ( 238 )

2018 ( 5816 )

2017 ( 5929 )

2016 ( 6215 )

Search Results: 1 - 10 of 251360 matches for " 张鹤 "
All listed articles are free for downloading (OA Articles)
 Page 1 /251360 Display every page 5 10 20 Item
 Statistics and Applications (SA) , 2014, DOI: 10.12677/SA.2014.34018 Abstract: 本文利用R软件主要讨论了两组专家对五个葡萄酒样品的评分及专家评分的合理性问题。首先，利用两个正态总体均值的假设检验评判两组专家的评分之间是否存在显著差异，从检验结果发现两组专家的评分是基本相符的，从而评比结果有一定的公平性与合理性。其次，利用均值的多重检验考察专家们对不同样品的区分度。在0.05的显著性水平下，专家们能够区分样品1与样品2、样品3、样品5，样品2与样品4，样品3与样品4。对五个样品的等级从高到低排序之后发现，专家们基本上可以区分等级相差为1的样品。但是专家们没有有效地区分出样品1与样品4(等级相差1.5)，样品3与样品5(等级相差1)。然后，运用系统聚类的方法将五个样品分为优、良、差三类。最后，采用距离判别分析法，利用训练样本建立判别函数，将训练样本回代进行判别，得到专家的误判率和正确率，从而利用判别函数对新的样本进行分类。By using R software, we discuss the evaluations of five wine samples by two groups of specialists and the rationality of the evaluations. First of all, by using the hypothesis testing of two normal population means, we judge whether there are significant score differences between two groups of specialists. The test results show consistency of scores of two groups of specialists, and thus the evaluation result has certain fairness and rationality. Secondly, by using multiple t test of the mean, we can investigate the degree of differentiation of different samples by the specialists. Under the significance level of 0.05, the specialists can separate sample 1 from samples 2, 3, and 5, samples 2 and 4, samples 3 and 4. By ordering the levels of five samples from high to low, we find that the specialists can basically distinguish samples with levels with level difference by 1. But specialists do not effectively distinguish samples 1 and 4 (level difference 1.5), samples 3 and 5 (level difference 1). Then we use the hierarchical clustering method to classify five samples to three classes: excellent, good, and bad. Finally, by using the distance discriminant analysis method, the discriminant function is established based on the training sample, then by discrimination of the training sample, we get specialists’ misjudgment rate and accurate rate, and thus we can use the discriminant function to classify the new samples.
 林志萍, 段鹤, 张欣 Advances in Condensed Matter Physics (CMP) , 2016, DOI: 10.12677/CMP.2016.53007 Abstract: 本文采用基于密度泛函理论的广义梯度近似方法和赝势平面波法的第一性原理计算讨论了PbTiO3体系的氧的化学势范围、(Pb1？xSrx)TiO3体系的磁性以及氧空位对该体系磁性的影响。结果表明，有Sr掺杂的情况下，(Pb1？xSrx)TiO3体系呈现了一定的弱铁磁性(x = 0.5时的最大磁矩小于0.04μB/unitcell)；当存在氧空位时，(Pb1？xSrx)TiO3体系具有铁磁性，磁矩为0.486μB/vacancy 和未掺杂的PbTiO3中由于氧空位的存在而产生的磁矩0.488μB/vacancy 一致。 Based on first-principles calculation, it is discussed for the chemical potential regions of oxygen of PbTiO3 system under the thermodynamics equilibrium conditions, the magnetism of (Pb1？xSrx)TiO3 and the effect of oxygen vacancy on the magnetism of (Pb1？xSrx)TiO3. Results displays that increasing Sr, (Pb1？xSrx)TiO3 appears the weak ferromagnetism (and when x = 0.5, the maximum magnetic moment is less than 0.04μB/unitcell). If there is a oxygen vacancy in (Pb1？xSrx)TiO3 system, it takes on the ferromagnetism and magnetic moment is 0.486μB/vacancy , which is agreement with the magnetic moment 0.488μB/vacancy of pure PbTiO3 system with oxygen vacancy.
 张鹤,谢旭 工程力学 , 2009, Abstract: 采用非线性有限元方法，评价了大跨度斜拉桥在车辆荷载作用下发生索桥耦合振动的可能性。以跨度为1400m的斜拉桥模型为例，通过车桥耦合振动分析获得主梁和桥塔的振动响应，将其作为拉索在支点处受到的激励，分别计算得到钢索和碳纤维(CFRP)索的振动响应。结果表明：不论是钢索还是CFRP索，其位移响应振幅均不大。由于较大跨度钢索的自振频率低且接近于桥梁的主要自振频率，此类钢索在车辆荷载作用下容易发生局部振动。相比较而言，CFRP索由于刚度较大随桥梁整体发生小幅振动。另外，激励持续时间长度对拉索的振幅影响不大。在拉索的主要固有频率范围内，梁、塔和拉索的固有频率之间没有明显的相关性，大跨斜拉桥在车辆荷载作用下发生索桥耦合振动的可能性不大。
 张鹤年 中国沙漠 , 1990, Abstract: 新疆策勒县绿洲处于塔克拉玛干沙漠南缘,沙害极其严重。经过6年的治理,现已从绿洲向外依次初步建成了窄林带多带式防沙林网、人工灌木林、固沙草带及拦沙河,构成长10公里、宽4.55公里的绿色屏障,为绿洲内的农牧业生产提供了较为适宜的生态条件。
 张鹤宇 牲畜兽医学报 , 1962, Abstract:
 张鹤宇 牲畜兽医学报 , 1963, Abstract:
 张鹤宇 牲畜兽医学报 , 1964, Abstract:
 张鹤宇 牲畜兽医学报 , 1964, Abstract:
 张鹤宇 牲畜兽医学报 , 1962, Abstract:
 张鹤宇 牲畜兽医学报 , 1959, Abstract:
 Page 1 /251360 Display every page 5 10 20 Item

 Home Copyright © 2008-2017 Open Access Library. All rights reserved.