差

In this paper, the maximum likelihood algorithm with process and measurement noise for nonlinear continuous-discrete system given by Jategaonkar and Plaetschke is improved in two aspects: 1 to avoid the disadvantages of sensitivities computation by common finite-difference method, in which the perturbation sizes should be selected optionally, an improved finite-difference method with best perturbations, is presented. 2 to improve the numerical stability of Jategaonkar's algorithm, maximum likelihood algorithm with fast triangular square-root decomposition filter is given.

摘要对Jategaonkar等人给出的同时计及过程及观测噪声的非线性连续-离散系统的极大似然算法从两个方面进行了改进：1给出了计算灵敏度的最佳摄动有限差分算法，避免了普通有限差分法计算灵敏度矩阵时需人为选择参数摄动量大小而带来的缺点；2给出了具有快速三角化平方根滤波的极大似然算法，提高了原算法的数值稳定性。

It was proved by Chi-square test that the number of observation of F2 individuals for the density of glandular trichome could fit the normal distribution, indicating the genetic charactistics of the density of glandular trichome as a quantitative trait.

不同亲本腺毛密度的一般配合力方差和不同组合的特殊配合力方差均达到了1%极显著水平；中烟90和8136的一般配合力效应较大，潘园黄×中烟90、潘园黄×RG17、8136×红大和红大×RG17的特殊配合力效应较大。

Basal and middle segments of 6 walls of the left ventricle（12 Segments were studied. Peaking displacement and Time to peak displacement were measured with Triplane－TTI. Then we calculated the maximal difference in Td and the standard deviation of Td.

取左室6个壁的基底段和中间段，总共12个节段，应用Triplane－TTI测量各节段收缩最大位移及达位移峰的时间Td），计算最大差值(Td-maxD和标准差。

This system uses the deuterium lamp as its blazed lamp-house, and makes mechanical turnplate in use of modulating light signal with two frequencies, which is drived by in-phase electromotor with constant velocity. A potomultiplier tube is used to conversion optical signal to electric signal. Using Lock-In Amplifiers to realize magnifying the metrical signal using difference method with two different frequencies. We also analyze its principle of each part of the apparatus and design the realization circuits of each part. The data analysis and the in-phase electromotor control circuits are fulfilled by SCM; the single chip control systems hardware interface and software design are given.

该系统的光路部分使用氘灯作为激发光源，用同步电机恒速驱动的机械盘调制出双频光信号，利用一个光电倍增管进行光电信号转换；信号处理部分采用锁相放大器实现信号双频差分处理，分析了其各组成部分的原理，设计了各部分的具体实现电路；使用单片机进行数据差分处理和电机控制，给出了单片机控制处理系统的硬件接口电路和软件设计。

Especially today when the change of accounting environment is taking place and accountants are faced with various challenges, higher accounting education can hardly fulfill the requirement of the age of intellectual economy. Firstly, it is ultimately handicapped by the concept lag and unadvised cultivation objective of education.

教育理念落后、培养目标定位不准确从根本上制约了高等会计教育的发展，课程设置不尽合理、教育手段陈旧、教材泛滥而低质等负面因素影响着施教的思路和水平，学生的专业理论不扎实、业务实践能力差、缺乏职业素养给高等会计教育带来尴尬，会计教师队伍整体科研能力弱、实务能力差、责任心不强等综合素质的欠缺更使高等会计教育的发展举步维艰。

The results from an example showed that the unbiased estimate of error variance could be obtained so that polygenic variance and polygenic heritability could not be underestimated. Moreover, the AIC values by using the average of two replications were less than that by using the observations of a replication.

在试验设计为重复内分组随机区组设计时，通过甘蓝型油菜初花期的遗传分析表明：这种方案的试验误差方差估计值无偏性好，可避免多基因方差和多基因遗传率被低估；重复观测值平均数的分离分析的AIC值低于利用单一重复资料的AIC值。

Judgement and Solution Methods of UMVUE ;2. The maximum likelihood estimate and uniformly minimal variance unbiased estimate of MTTF were made on the one-unit system whose lifetime was assumed to be on GAMMA distribution.

讨论寿命服从单参数GAMMA分布单元平均寿命的极大似然估计和一致最小方差无偏估计；应用BASU定理求出了单元可靠度及串联系统可靠度的一致最小方差无偏估计。

Under CLM, OLS is not only BLUE, but also the minimum variance unbiased estimator, that is, among linear and nonlinear estimators, OLS estimator gives the smallest variance.

在经典线性模型假设下，OLS不仅是BLUE，而且是最小方差无偏估计量，即在所有线性和非线性的估计量中，OLS估计量具有最小的方差。

On the base of large quantitative test, using coal petrography and organic geochemical data, the source of oil and gas in the coal-measures is analyzed. And it is concluded that the area's Yan'an group coal-bed has a low potential of oil production, and the oil and gas contained in the coal-measures and superjacent strata comes from underlying Upper Triassic Yanchang group strata. After a series of parameters of coal seam and surrounding rocks are tested, gas formation, storage, preservation, permeability of the coal-rock seam are analyzed and evaluated.

本文在大量测试工作基础上，利用煤岩学与有机地球化学资料，分析了煤系油气的来源，认为本区延安组煤系煤层生油潜力差，煤系及其上覆地层所含油气为下伏上三叠统延长组源岩所生，油气主要通过迭置的砂体、不整合面、构造裂缝等自下向上运移进入煤系；通过对煤层及围岩一系列物性参数的测试，分析与评价了煤岩层的生、储、盖、渗性能与可抽放性，得出主采4_(-2)号煤层属中等储集、低渗透层，围岩封闭性差，渗透性高，煤层瓦斯含量低，而顶板砂岩瓦斯含量高，为采面瓦斯涌出的主要来源。

Based on Wu's elimination method and "divide-and-conquer" strategy, the undetermined coefficient method for constructing polynomial conservation laws of nonlinear differential-difference equations was improved. Furthermore, a Maple package CLawDDEs was developed to automatically derive conserved densities and associated fluxes of polynomial differential-difference equations.

基于吴消元法和"分治"策略，改进了基于标度不变性构造非线性微分差分方程多项式形式守恒律的待定系数算法，并在计算机代数系统Maple上实现了改进后的算法，其中的软件包CLawDDEs可自动推导出微分差分方程的守恒密度及连带流。

As she looked at Warrington's manly face, and dark, melancholy eyes, she had settled in her mind that he must have been the victim of an unhappy attachment.

每逢看到沃林顿那刚毅的脸，那乌黑、忧郁的眼睛，她便会相信，他一定作过不幸的爱情的受害者。

Maybe they'll disappear into a pothole.

也许他们将在壶穴里消失