条件观测

Second, when the system does not satisfy such detectability but satisfy other conditions, there is a gain matrix ensuring the asymptotic convergence of the observer error, and the sufficient conditions and the method of solving gain matrix are obtained similarly.

其次， 当系统不满足该可检测性，但满足其它条件时，仍存在使得观测误差渐近收敛的增益矩阵，并类似地得到了增益矩阵满足的充分性条件和计算方法。

The simulated results after the assimilation show that it is the best to perform the intensive radiosonde observation in the upstream of the rainfall area and the moisture passageway area at the same time to improve the heavy rainfall forecast.

从个例研究结果来看，在同化时间窗都为12小时的条件下，使用加密探空观测资料进行三个时刻的数据同化形成的初值明显优于同化两个时刻的观测资料形成的初值。

In order to investigate the excitation mechanism and response characteristics of wind-rain induced vibration of stay cable,an instrumentation system of wind-rain induced vibration measurement,which consists of anemometer,rain gauge and accelerometer,was installed on the Dongting Lake Bridge,Yueyang,China.

为了研究斜拉桥拉索风雨振的机理及响应特征，在岳阳洞庭湖大桥建立了由风速仪、雨量计、加速度传感器组成的风雨振现场观测系统，观测到了多次拉索风雨振现象；得到了发生拉索风雨振时风速、风向及雨量的基本条件，分析了风雨振时拉索振动的幅值、主振频率、模态参与特性及空气动力负阻尼比等响应特征。

For the multi-channel system with multiplicative noises under multi-sensor observation an optimal fusion estimation algorithm is proposed on the conditions that the multiplicative noise is in the form of a general stochastic matrix and the measurement noises of each sensor are correlated with the dynamic noise.

第二，本文针对多传感器观测下的多通道带乘性噪声系统，在乘性噪声为一般矩阵且各个传感器的观测噪声分别与系统的动态噪声同时刻相关的条件下给出了状态最优滤波融合算法、最优固定域平滑算法及最优固定域反褶积算法。

The results indicated that compared with short photoperiod, under long photoperiod, plant height, caudex, leaf and leaf number increased, florescence delayed; The phase from the calyx differentiation stage to gynoecia differentiation stage lasted 3~4 days.

采用10h和16h两种光照条件对紫苏进行处理，观测光周期对紫苏生长发育的影响，结果表明：与短日照条件下的相比，长日照条件下生长的供试材料叶片数增加，叶片增大，茎增粗，植株增高，开花延迟；花芽分化从萼片原基形成开始，到雌蕊形成为止，持续3~4d。

Careful analysis on NBE can facilitate nowcasting of severe weather events and further understanding of their evolution. After detailed study on three cases concerning with NBE, it is concluded:(1) NBE triggered by fast moving echo in upstream is an important indication of disastrous wind;(2) NBE can develop into severe storm under proper conditions. There are often two stages during this kind of growing: the first is developing of initial echo, the second is snap growing of echo core;(3) Doppler radar reflects outflow of downburst as a nearly ringed NBE. Inside look on downburst can be obtained combining NBE with other data.

文章结合发生在上海的3次强对流天气个例，详细分析了弱窄带回波在分析和预报强对流天气中的作用，得出以下结论：（1）上游移动强回波的出流边界导致的弱窄带回波是大风预警的重要判断参考；（2）在合适的层结状态和抬升条件下，弱窄带回波会强烈发展，并导致局地雷雨大风，这类强对流天气的发展有两个比较重要的阶段：弱窄带回波上初始回波的发展和回波跃增；（3）下击暴流造成的地面出流在雷达回波上表现为近似圆弧的弱窄带回波，这种弱窄带回波与其他雷达观测特征以及地面观测相结合，有助于对产生下击暴流的对流云的发生发展过程进行细致分析。

It is important to reduce the span of the hard roof to avoid its impact load on supports. However, at longwall top coal caving face, the periodical weight of roof is a main factor that crushes the top coal, which is beneficial to the top coal recovery. How to use the roof pressure safely is of crucial importance in top coal caving. Based on field monitoring, theoretical analysis of strata movement, the numerical model of compound structure of hard roof stepped cantilever and the top coal cantilever beam is built, and the parameters of the model are also determined. The elasto-plastic finite element method is used to analyze the effect of hard coal fracture under the abutment pressure of hard roof, and the cracking coefficient is defined according to the stress state of the element.

通过对岩层移动的现场观测，建立了&两硬&条件综放采场台阶悬臂—悬臂梁组合的煤岩组合结构力学模型，并以此煤岩结构为基础，建立&两硬&条件综放采场顶煤压裂的有限元数值模型，分析了坚硬顶板不同来压步距对坚硬顶煤的压裂效应，并确定了合理的支架阻力，从而对坚硬顶板进行有效的控制，消除坚硬项板对采场的冲击隐患，同时保证采场矿压对坚硬顶煤的有效压裂，达到提高顶煤回收率之目的，由此形成了坚硬顶煤、坚硬顶板条件下综放采场围岩控制的基本理论和方法。

Second, according to the characteristic of soft-ground ,when we disposed of the obser-vation data of every period from the earth subsidence network, we chose three adjustment ma-thematics models including adjustment by classics; adjustment by free network and adjustment by selecting proposal stable points to deal with the solution .

其次根据软土地基的特点，为达到观测成果能合理处理目的，在沉降变形监测网数据处理时，利用了三种平差数学模型即经典平差、自由网平差和拟稳平差分别进行观测基准网的解算，并把求算结果进行比较对照，从而选出最合理的能符合本场地实际条件的一组解算成果作为我们后面的变形成果精度分析的依据。

The polyurea coating was tested with Taber tribomachine and the highp ressure water jet erosion tester for studying the wear behavior of polyure coating under conditions of dry friction and highspeed water jet contained sand. The morphology of the coating was observed with SEM and Chromatic confocal 3D Profiler. The surface component of test samp les was measured by FT2IR Spectrometer and Electron Energy Disperse Spectroscopy. The p roperties of polyurea coating under two testing conditionswas analyzed.

为研究聚脲涂层在干摩擦条件下和高速含砂水流冲蚀条件下的性能变化情况，用 Taber 磨损试验机和高速含沙水射冲蚀磨损试验机测试了聚脲涂层的磨损性能，用扫描电子显微镜和白光共焦三维轮廓仪观测涂层的磨损表面形貌，用表面红外光谱和电子显微镜能谱元素分析了涂层表面试验前后的组分变化，分析了涂层在2种摩擦条件下的磨损情况。

Unlike the common just noticeable difference study, the JNDs on natural image content by human eyes under general viewing conditions are evaluated.

与以往JND研究不同，针对视频显示应用，研究了在一般观测条件下，友眼观测自然图片时上述4种图像质量影响因素的JND值。

Singer Leona Lewis and former Led Zeppelin guitarist Jimmy Page emerged as the bus transformed into a grass-covered carnival float, and the pair combined for a rendition of "Whole Lotta Love".

歌手leona刘易斯和前率领的飞艇的吉他手吉米页出现巴士转化为基层所涵盖的嘉年华花车，和一双合并为一移交&整个lotta爱&。

This is Kate, and that's Erin.

这是凯特，那个是爱朗。