查询词典 test-taking

The basic approach of protecting people from being hurt or killed in an accident is to improve crashworthiness of vehicles. This paper starts with discussing theories and methods for vehicle passive safety design, which included experiential methods, analytic methods, multi-body dynamics methods, crash test methods and the finite element method. Emphasis will be paid to the basic FEM theories and algorithms of impact problems. Topics discussed include the governing equation, element discretization, hourglass control, time integration, material model, shell element algorithms and contact-impact algorithms. For more reliable simulation results, this paper then conducts study on how to accurately get material model parameters by combining the FEM method with experimental method, and develops relevant material test machine and parameter calculating software. Based on that, basic typical impact simulation and test validation study are conducted. On the basis of the above work, the paper studies the thin-shell structures'crashworthiness, which was affected by the following factors: spot-weld features, shell thickness, cross-section and pre-deformation. As to vehicle parts'crashworthiness, the paper conducts simulation study of designing energy-absorbing steering system and adaptive airbag system. A practical energy-absorbing steering wheel is designed as an example. In further depth research, the paper suggests several inverse quantificational methods for vehicle crashworthiness design based on the ideal crash characteristics. The above theories and methods are applied with good results through several practical vehicles' crashworthiness design and improvement.

文中对汽车碰撞安全性的设计理论和方法进行了归类和总结，其中包括经验法、解析法、多刚体动力学法、试验法以及有限元方法等；重点介绍了碰撞有限元法的基本理论和有关算法，涉及到有限元求解控制方程、单元离散、沙漏模态控制、时间积分、材料模型和应力修正、薄壳单元算法以及接触碰撞界面算法等，探讨了有限元计算中的材料模型参数获取技术，开发了相应的材料试验装置及材料模型参数反求软件，在此基础上进行了基本的碰撞仿真算例和试验对比研究；文中通过应用有限元方法研究了薄壁构件的碰撞吸能特性，指出了设计薄壁吸能构件时需要考虑的几个主要影响因素，即焊点、壁厚、横截面和预变形等；在关于车辆部件的碰撞安全性能设计中进行了吸能转向机构和自适应安全气囊的仿真研究，提出了吸能转向机构和自适应安全气囊的仿真研究方法；文中最后探讨了整车碰撞性能的设计与改进方法，提出了以理想碰撞特性为目标，采用分段加速度或者根据碰撞时间进行设计的反推设计法、部件吸能仿真优化设计法等量化设计方法，并通过综合应用文中所讨论的相关技术进行了整车碰撞性能的设计与改进实例研究，所选定的车型是大众化的普通轿车和碰撞安全性基础较差的微型面包车，研究结果表明，本文所提出的设计与改进方法是适用而有效的，具有重要的工程实用意义和价值。

The triple test (also known as the Leed's test or the Bart's test) looks at the levels of blood chemicals between 16 and 18 weeks, to find out the chance of the of baby having Down's syndrome, spina bifida or anencephaly.

三重考验（也称为作为低能电子衍射的测试，或巴特的测试）着眼于各级血液化学品之间的16和18个星期，以了解的机会，该婴儿有唐氏症儿，脊柱裂或anencephaly 。

MATERIALS AND METHODS: The Ames test,the mouse micronucleus test and the mouse sperm abnormality test were used to evaluate the genotoxicities of bezoar antidotal tablet.

材料与方法：采用 Ames试验、小鼠骨髓细胞微核试验和小鼠精子畸形试验对牛黄解毒片进行遗传毒性检测。

In whole test process, to compared with control group, hepatic hepcidin gene expression of test group on different phases had obviously differences with retinoic acid was administered. On early phase of test group , relative gene expression contents of hepcidin were gradually fall and the lowest level was on 8th、9th、10th day, then the hepcidin level gradually was ascendent. The curve was like a cavate parabola.

在实验周期内，模型组与对照组比较，肝脏铁调素基因表达在维甲酸灌胃的不同时间，存在明显差异：早期5、6、7天铁调素基因相对表达量逐渐下降，在第8、9、10天达到较低值，随后有回升，呈现凹陷的抛物线变化趋势；而对照组基本处于水平的轻微波动变化。

The common method, that all strong-correlation terms of the model are eliminated, can bring the loss in the engineering application, so the new method is proposed that the identified model reserves some correlation. The augmented matrix A is constructed by the outputΔW and the matrix S. The"determinating order based on ratio of determinant"is brought out to screen the strong-correlation terms in the structure identification. The latent root estimation is improved in screening the eigenvalues and eigenvectors. Thus the estimation precision is improved greatly.The consistence check of guidance instrument error coefficients of flight test and ground test is the purpose of flight experiment. The causes of inconsistency of the two models are analyzed. The hypothesis test of linear regression model based on F statistics is proposed to check the consistence.Finally, the instability of error coefficients is probably caused by the change of the flight environments, therefore, the relation between the error coefficients and flight environment is analyzed. The approach is presented to identify SINS guidance instrument error models and compensate the error in the segmented sections corresponding to the change of vertical acceleration of aircraft.

在结构辨识中，常用的方法由于将模型中的强相关项全部剔除而给工程应用带来损失，因此，本文提出了新的有益思想，即在保留一定相关性的基础上进行辨识：将输出向量ΔW与环境函数矩阵S构成增广矩阵A，然后采用"比定阶行列式"来剔除相关向量的方法，这样既可以尽可能多地保留了对落点影响大的强相关参数，又可以对落点影响小的强相关参数给予剔除；在参数估计中，改进了特征根估计中特征根和特征向量的筛选方法，提出"近零"准则，从而大大提高了参数估计的精度；再者，鉴于天地模型"一致性"检验是飞行试验和SINS制导工具误差系数分离的主要目的，因此，本文又深入分析了造成天地模型不一致的原因，提出了采用基于F统计的线性回归模型假设检验方法来进行捷联制导工具误差模型的天地"一致性"检验；最后，鉴于飞行环境剧烈变化可能会对惯性仪表误差系数稳定性带来一定的影响，因此本文深入地分析了SINS制导工具误差系数与外界环境的关系，提出了基于过载变化大小的分段辨识和分段实时补偿的算法。

Finally, we present the instruments test method, results of BERT and results of simulation and test of signal integrity according to our design of gigabit backplane test system.

最后结合我们设计的千兆位背板测试系统，给出了仪器测试方法，误码率测试结果和信号完整性的仿真和测试结果。

NMath Stats contains a data table class with functions for computing descriptive statistics, such as mean, variance, standard deviation, percentile, median, quartiles, geometric mean, harmonic mean, RMS, kurtosis, skewness, and many more; PDF, CDF, inverse CDF, and random variable moments for a variety of probability distributions, including normal, Poisson, chi-square, gamma, beta, Student's t, F, binomial, and negative binomial; Combinatorial functions, such as factorial, log factorial, binomial coefficient, and log binomial; Multiple linear regression; Basic hypothesis tests, such as z-test, t-test, and F-test, with calculation of p-values, critical values, and confidence intervals; One-way and two-way analysis of variance and analysis of variance with repeated measures; Multivariate statistical analyses, including principal component analysis and hierarchical cluster analysis.

nmath统计包含一个数据表的阶层与职能计算描述性统计，如平均，方差，标准差，百分位，中位数， 25 ％，几何平均数，调和的意思是，有效值，峭度，偏度，还有更多的； PDF格式，民防部队，逆民防部队，并随机变量矩的各种概率分布，包括正常，泊松，卡方检定，伽玛，测试版，学生的吨，男，二项式，并负二项分布；组合的功能，例如阶乘，日志阶乘，二项式系数，并登入二项式；多元线性回归；基本假设测试，如的Z测试， t检验， F检验，计算p值，临界值，和置信区间；之一，双向和双方法方差分析和方差分析与反复的措施；多元统计分析，包括主成分分析和聚类分析。

In this paper, univariate or/and bivariate binormal model was established and its parametrers was estimated by the"method of scoring". To calculate the statistical significance of the difference between two ROC curves using any one of three distinct statistical tests: the bivariate Chi-square test, the area z-score test, and the TPR z-score test.

本文探讨了单变量、双变量双正态ROC模型的构建及其参数的最大似然估计方法；采用双变量卡方检验、真阳性率z检验、面积z检验三种方法比较了ROC曲线间是否具有显著性差异。

Biuret test A test for the presence of proteins, in which sodium bydroxide is added to the test solution, followed by drops of 1% copper sulfate solution.

双缩脲试验：鉴定蛋白质存在的试验。在待检测溶液中加入氢氧化钠，然后滴加1％硫酸铜溶液。

After 21 days, the local histological and immunological effect were investigated by muscle stimulation test, lymphocyte blastogenesis test and cytotoxicity test.

植入21天后分别采用肌肉刺激实验，刀豆蛋白A诱导的脾淋巴细胞转化实验和补体依赖性细胞毒实验分析生物衍生骨对动物机体局部组织的影响和免疫功能的影响。

Finally, according to market conditions and market products this article paper analyzes the trends in the development of camera technology, and designs a color night vision camera.

最后根据市场情况和市面上产品的情况分析了摄像机技术的发展趋势，并设计了一款彩色夜视摄像机。

Only person height weeds and the fierce looks stone idles were there.

只有半人深的荒草和龇牙咧嘴的神像。