查询词典 variation coefficient

It is shown from the study results that (1) SSC has obvious neap-spring and seasonal variations with periods being 14.7 days and 368 days, respectively, on an average, SSC during the spring tide was 2.96 times as much as that during the neap tide, and SSC in winter was twice as much as that in summer;(2) correlation coefficient between daily SSC and tidal range on the same day in a mean neap-spring period of 15 days was 0.86, and correlation coefficients between tidal range and daily SSC with one day and two day lag were 0.99 and 0.93, respectively, which indicates that the effect of tidal range variation on SSC has a one day or two day hysteresis;(3) the monthly mean SSC was negatively correlated with the monthly mean water discharge at the Changjiang River Datong station, especially well with the water discharge with a lag of 19 days.

悬沙浓度具有显著的大、小潮和季节性变化，变化周期分别为14.7 d和368 d，平均而言，大潮为小潮的2.96倍，冬季为夏季的2倍；2）平均大、小潮半月周期中日悬沙浓度与同日潮差之间的相关系数为0.86，与前1日潮差之间的相关系数为0.99，与前2日潮差之间的相关系数为0.93，反映潮差变化对悬沙浓度的影响有1~2d的滞后效应；3）月均悬沙浓度与长江大通站的月均流量呈显著负相关，尤其与流量滞后19d的相关性最好。

In the meantime, a new relation between the coefficient of variation for a normal variate and its sample size is achieved, where the probability to make mistake Ⅱ is considered 5 The probability distribution of fatigue strength at given life under large sample size determined by a new method is found to follow the log-normal distribution and normal distribution, and a new method are developed to estimate the characteristic parameters of probability distribution of fatigue strength from the probability distribution of traditional tensile properties.

根据P-S-N曲线的要求，采用概率统计方法，导出了考虑犯Ⅱ类错误的概率时获取给定精度P-S-N曲线所需的最少子样容量，引入了不同方法获取的P-S-N曲线结果是否趋同的判别标准，得到了P-S-N曲线的寿命求解法和系数求解法获得趋同结果的条件。 5）研究了大子样条件下指定寿命时疲劳强度的概率分布，并提出了根据拉伸性能的分布估算材料疲劳强度概率分布参数的一种方法。

As detect blemish numerary increases, newer blemish appears on average of rate all be worth increase gradually, updated coefficient of variation is reduced gradually.

随着检测到缺陷数目的增加，更新的缺陷平均出现率的均值逐渐增加，更新的变异系数逐渐减小。

In order to determine the convergence of the line samplingbased reliability sensitivity method,the variance and the variation coefficient were derived for the reliability sensitivity estimation based on the line sampling.

为判别线抽样可靠性灵敏度分析的收敛性，推导了线抽样可靠性灵敏度估计量的方差和变异系数的计算公式，近似计算了线抽样可靠性灵敏度在给定置信度下的置信区间。

In order to determine the convergence of the line sampling -based reliability sensitivity method,the variance and the variation coefficient were derived for the reliability sensitivity estimation based on the line sampling .

为判别线抽样可靠性灵敏度分析的收敛性，推导了线抽样可靠性灵敏度估计量的方差和变异系数的计算公式，近似计算了线抽样可靠性灵敏度在给定置信度下的置信区间。

In order to compare the convergence of the importance sampling based reliability sensitivity analysis and Monte Carlo based reliability sensitivity analysis, the variance and variation coefficient of the reliability sensitivity assessment are derived in this contribution.

为了比较重要抽样与直接Monte Carlo方法在分析可靠性灵敏度时的收敛性，推导可靠性灵敏度估计量方差和变异系数的计算公式，近似计算重要抽样可靠性灵敏度估计量在给定置信度下的置信区间。

Combining with the National Natural Science Foundation ofChina(No.50478032), following researches were done in this thesis: 1 The variation regularity of the ultimate anti-bending capacity of therectangular-sectioned beam with different corrosion has been obtained through thequalitative analysis of 48 beams (32 corroded beams and 12 comparing beams) withaccelerated corrosion; 2 The conclusion has been obtained that the strain of corroded steel bar andconcrete no longer fit in with the assumption of plane section through the analysis ofthe strain data, the strain relation of steel bar and concrete in the mid-span section ofvariously corroded beams at ultimate has been obtained. Through the building of newgeometric relation, the expression of the height of compressive area in the corrodedbeam with rectangular section has been deduced, and the formula with corrosion rateas the main variable for the anti-bending capacity of the corroded concrete beam hasbeen suggested and verified by experiment.; 3 The influence of steel bar corrosion and the concrete regression to the flexureductility coefficient of the corroded structure component has been analyzed. Based onthe relation of steel bar and concrete at yield and ultimate, the expression for theflexure at yield and ultimate of corroded reinforced concrete beam, and the model forthe calculation of the flexure ductility has been built.

本文结合国家自然科学基金项目(50478032)"既有钢筋混凝土桥梁时变可靠度研究"，主要进行了以下研究工作： 1通过对48根快速锈蚀钢筋混凝土矩形截面梁(32根锈蚀梁和12根对比试验梁)数据的定性分析，得到了不同锈蚀率下，锈蚀钢筋混凝土矩形截面梁极限抗弯承载力的变化规律； 2通过对应变数据的分析，论证了锈蚀构件钢筋和混凝土的应变不再符合平截面假定的结论，并通过回归分析得出了不同锈蚀率的螺纹钢筋梁和光圆钢筋梁在极限弯矩作用下，跨中截面处钢筋应变和钢筋处混凝土应变的关系，通过构造新的几何关系，得出了锈蚀钢筋混凝土矩形截面梁计算受压区高度的表达式，既而得出了以锈蚀率为主要变量的锈蚀钢筋混凝土矩形截面梁的正截面抗弯计算建议公式，并通过试验数据加以验证； 3分析了钢筋锈蚀和混凝土劣化对锈蚀构件曲率延性系数的影响，结合钢筋屈服和极限弯矩两种状态下钢筋和混凝土的应变关系，分别得到了锈蚀钢筋混凝土矩形截面梁屈服曲率和极限曲率的计算表达式；既而推导出曲率延性系数的计算模型。

The experiment accuracy test showed that the coefficient of variation of the positive mixed serum was 5.04%, and the CV of negative mixed serum was 1.10%.

实验精确度检测阳性混合血清的变异系数为5.40%，阴性混合血清变异系数为1.10%。

The optimum conditions for extraction was proved practicable by condition filtration and orthogonal design with supersonic wave method .The results showed that the optimum conditions for extraction to ultrasonic method is : methanol (φ=40,20ml),and 15℃ for 30 min ,this paper has determined nicotine contents that is 23.50mg/g at absorption peak (λ=262nm) by HPLC with an eluent consisting of methanol –potass Phosphate alleciate (pH=3) with the recovery and coefficient of variation are 101.52% and 0.91%.

通过超声波提取方法进行条件筛选和正交化实验，确定了烟草中尼古丁的最佳提取条件，结果表明，超声波最佳条件是：甲醇浓度40%，固液比1：20，提取时间30 分钟，超声温度15℃，用高效液相色谱方法在波长262nm 处测定尼古丁的含量，流动相组成为甲醇：磷酸二氢钾缓冲溶液=10：90，测得烟草中尼古丁的含量为23.50 mg/g，平均回收率为101.52%，相对偏差为0.91%。

Results showed that the coefficient of variation of mixing uniformity of 65% Lysine Sulphate in 1, 2.5 and 4% premix was 1.70, 3.99 and 0.07% respectively.

试验证明，65%赖氨酸在1、2.5和4%预混料中的混合均匀度变异系数分别是1.70、3.99和0.07%。

The system can be widely used in belt weighing and batching process control,etc.

介绍了基于智能模糊控制的嵌入式配料系统的设计方法，对模糊PID控制过程和系统调零作了重点的讨论，同时给出了PID控制的程序流程图和系统定长调零子程序。

"I dunno," she answered,"but if you show me aroun', I'll recognize it from the lighthouse just outside the porthole."

"我不知道，"她回答说，"如果你能带我转转，我能认出来的，因为灯塔就在舷窗外。"