结构稳定性

The results from confirmatory factor analysis indicated:(1) The structural model of children's early mathematical ability was reasonable and it had good structural validity. In detail, children's early mathematical ability was explained by number, arithmetic, measurement, space/geometry and pattern;(2) The structure of children b early mathematical ability was stable across different ages but the structural model was not consistent completely;(3) Boys' structural model was identical with that of girls'.

经验证性因素分析发现：(1)儿童早期数学认知能力的结构模型是合理的，可接受的，具有较好的构想效度，具体讲，数、计算、测量、空间／几何和模式认知能力五个维度共同解释著儿童早期的数学认知能力；(2)不同年龄儿童早期数学认知能力的结构具有稳定性，但是结构模型並不完全一致，某些项目的解释率有所不同；(3)男、女儿童早期数学认知能力的结构模型具有一致性。

Firstly, this paper investigated roundly the basic theory of the ambient vibration method, analyzed systematically the main methods of ambient vibration identification, and discussed their advantages and disadvantages. Then we established the finite element model of structural dynamics and test model and analyzed their mutual relation, improved MUSIC method and correlation function method in the harmonic identification, and gave the subspace method and correlation function method based on continuous model, which is multi-harmonic retrieve technique. And then, this paper also puts forward least-squares method to estimate directly structural physical and modal parameters; this approach replaced the derivative operator in the continuous time model with an equivalent approximation, and estimated the physical parameters of structures by the least-squares method. And then, we discussed the approximation methods of derivative and their convergence. Finally, this paper researched the modal parameters of a frame structure by the simulation and test. The results demonstrated that subspace method, correlation function method and the least-squares method are effective and stable respectively.

全面地研究环境振动识别方法的基本理论，系统地分析环境振动识别方法的主要方法，讨论它们的优点和不足；建立结(来源：6666AB44C论文网www.abclunwen.com)构动力学的有限元模型和试验模型，分析有限元模型与试验模型之间的相互关系；改进谐波识别中的MUSIC识别方法和相关函数识别方法，给出大型结构模态识别的连续型的子空间分解识别方法和相关函数识别方法，这个方法是多元谐波识别方法；提出直接识别结构的物理参数和模态参数的最小二乘方法，这个方法利用导数的近似值代替导数值，并运用最小二乘方法识别结构的物理参数，讨论导数近似值的选择方法，分析算法的收敛性；通过仿真计算和模型实验，研究高层框架结构的模态参数识别，验证子空间分解识别方法、相关函数识别方法和最小二乘识别方法的有效性，算法的稳定性；从理论和试验两个方面分析和研究噪声对识别精度的影响，影响识别精度的因素，以及部分模态成分的模态参数不能够被识别的原因。

When the molar fraction of SnO2 is 83%, the main component of the coating isO2 solid solution with rutile structure. When the molar fraction of SnO2 is 44%, the main components of coating are theO2 solid solution with rutile structure andO2 solid solution with fluorite structure. When the molar fraction of SnO2 is 17%, the main component of the coating isO2 solid solution with fluorite structure. Annealed at higher temperature than 450 ℃, CeO2 is found in the coating containing 83%Sn, and there is not SnO2 in the coating containing 83%Ce, which suggests that fluoriteO2 has higher thermal stability than rutileO2. When the molar fraction of SnO2 increases, the dispensability of the coatings is improved greatly.

结果表明：通过控制制备条件可获得具有纳米结构的钛阳极涂层；当Sn的摩尔分数为83%时，涂层主要为金红石相的O2固溶体；当Sn的摩尔分数为44%时，涂层中金红石相O2固溶体和萤石结构的O2固溶体共存；当Sn的摩尔分数为17%时，涂层由萤石结构的O2固溶体组成；高于450 ℃退火时，含83%Sn的涂层中出现CeO2相，而在含83%Ce的涂层中没有出现SnO2相，表明在相同的溶质浓度下，萤石结构的O2固溶体比锡基金红石相O2固溶体具有更好的热稳定性；而涂层中的SnO2具有明显改善涂层分散性的作用。

An instantaneous optimal semi-active control method is put forward. Combined sliding mode control with lyapunov's stability theory, the control weights matrix, which can minimize structural instantaneous energy, is designed. Simulation and shaking table test is conducted to validated the method's effectiveness. To solve combination explosion of controlled structural state encountered in high-rise building control, the semi-active control strategy, which can drive structural state point to reach the sliding mode switching band, is designed by using sliding mode control theory, and genetic algorithm is used to find the optimal semi-active switching to drive the structural state point to sliding mode switching band at prestissimo speed.

提出了一种瞬时最优半主动结构控制方法，利用滑模变结构控制理论和Lyapunov稳定性理论设计使结构瞬时能量最小的半主动控制权矩阵，仿真实例和振动台试验验证了本文所提方法的有效性和实用性；为解决在高层建筑半主动控制中半主动控制器状态组合爆炸的问题，利用滑模变结构控制理论设计在Lapunov稳定意义下使结构在运动状态空间中任一相点于以最快速率到达滑模切换带的半主动控制策略，并用遗传算法找出了最快到达滑模切换带的半主动控制切换组合。

Also, during this process, the water content in vegetation increases and keeps stable gradually, and the water environment in ecosystem will become suavely.

摘 要：本文以南亚热带常绿阔叶林为基本，同时探讨了热带南亚热带森林演替系列中8种生态系统类型的水分结构，发现植被水分结构的恢复与土壤水分结构的恢复是不同步的，50a以上没有受扰动的土壤，其土壤水分结构在时空上才趋于稳定；植被水分结构的时空稳定性基本上与生态系统的演替状况一致；为满足植被蒸腾的需要，植被中水分的月更新次数随着群落向顶极系统的演替而逐渐减少。

Analysis result shows that the dynamic interaction between wheel and rail and the rail-pad force of the strengthened track are little bigger than those of the unstrengthened track,the safety grades of the tracks are same,the strengthened track can benefit to decrease the displacements of all components of track structure obviously,to restrain the deformation of track effectively,and to reinforce the stability of railway,especially the lateral displacement and the gauge enlargement of the strengthened rail are about 33% of original rail.

分析结果表明：强化后轨道结构的轮轨动态相互作用力及轨枕支点压力均较强化前的相应值略大，但皆属相同安全合格等级；强化轨道结构位移大幅度降低，有效抑制轨道结构变形，增强线路稳定性，尤其是钢轨横向位移和轨距动态扩大量较强化前下降十分显著，前者仅约为后者的1/3左右；强化轨道也有利于降低轨下结构振动和减轻列车提速后对轨下基础的破坏。

For preparing for the researches of text digital watermarking and advantaging other researchers" development when using the Chinese mathematical expression theory, this paper designs and realizes a development platform of Chinese mathematical expression. It has been proved by experiments that the platform"s function, execution speed and stability can satisfy the requirements of conversion and operation of enormous data.This research found out that the structure information of Chinese have plenty redundant information that can be used by the Chinese mathematical expression for the digital watermarking, the data embedded can possess better robustness. Based on this finding, this paper designs a kind of text digital watermarking method of embedding watermarking by using Chinese structure, and realizes the method by using the Chinese mathematical expression platform.Considering the watermarking embedding algorithms importance to the robustness of the text digital watermarking, this paper makes fully use of the advantage of the Chinese mathematical expression theory to design a kind of layered text method, which has being realized by using the Chinese mathematical expression platform. The layered text method can handle the text as a solid structure, and the embedding data havepreferable robustness.Finally, based on the researches of the text digital watermarking method and the text layered method, this paper integrates the method of making use of the Chinese structure embedding watermarking with the robust algorithm based on text layered, and realizes a brand-new text digital watermarking method. Proved by lots of experiments, this brand-new method has good robustness and better invisibility.

为了为研究工作做准备和方便其他使用汉字数学表达式理论体系的人进行开发，本文基于汉字数学表达式理论设计实现了一个汉字数学表达式平台，实现了Unicode汉字集中的汉字、汉字数学表达式、汉字的Unicode码之间的相互转化、依据汉字数学表达式提取汉字的结构信息、由汉字数学表达式在非中文平台上不依赖字库显示汉字的图像等功能，使用复合文档技术和流压缩技术进行数据的存储，使用对汉字数学表达式进行二叉树拆分来处理汉字数学表达式中包含的信息，使用自定义哈希函数来提高运行速度，实验证明，该平台功能、速度和稳定性完全能满足大量数据的转化和运算要求；通过研究表明汉字的结构信息中存在大量可使用汉字数学表达式理论加以利用的水印加载空间，加载在该空间的数据可以具有较好的鲁棒性，基于此，本文设计了一种利用汉字结构加载水印的文本数字水印方法，并使用汉字数学表达式平台将其实现；由于水印嵌入算法对于文本数字水印的鲁棒性至关重要，本文充分利用汉字数学表达式理论的优点，设计了一种文本分层的方法，并使用汉字数学表达式平台将其实现，使文本成为一个立体的空间，使嵌入在其中的数据具有更好的鲁棒性；最后在基于汉字数学表达式的文本数字水印嵌入方法的研究和基于汉字数学表达式的文本分层方法的研究的基础上，结合利用汉字结构嵌入水印的方法和基于文本分层的抗攻击文本水印嵌入算法实现了一种全新的文本数字水印方法，经实验证明，该方法有良好的鲁棒性和较好的隐蔽性。

And the lives near the tunnel also will be menaced by the threat of explosion.

爆炸时隧道衬砌结构的稳定性是隧道安全与周围结构物安全的基础，为了解在隧道内爆炸事故引发的衬砌结构动力响应规律，探讨隧道衬砌结构的损伤状况，对盾构隧道衬砌结构抗爆具有深远的意义。

Tudy on the structure and stablities of anion cluster(SiO_2)_nX~-3MR (three-membered ring) structure, 2MR (two-membered ring) linear chain structure and pseudotetrahedral cage structure have been proposed for the anion cluster (SiO_2)_nX~-(n=1~5 X=_, 0, OH).

iO_2_nX~-离子团簇结构和稳定性的理论研究主要研究(SiO_2)_nX~-(n=1～5 X=_，O，OH)离子团簇的三类典型结构(三元环结构、二元环链状结构和四面体笼状结构)。

In the process of building and using the mass concrete structures, because of the effect of out-side condition and themselves, some faults will form in the structure, these faults will effect the bearing capability and endurance Using nondestructive testing method to test the concrete"s quality and diagnose its healthy, which has the significant sense in assessing the safety stability and research of the administering diseasesThis dissertation mostly researched the testing methods in the mass concrete structure, discussed the principles, methods, features, sphere of application of the ultrasonic testing in the mass concrete structure with faults, used dynamic FEM to simulate the testing process, discussed when the concrete structure with cracks is under the effect of the pulse, how the elastic waves propagate and what are their changing feature, Researched the principles of the first-arriving waves" phase when the cracks" depths are not same, obtained the relation between the inversion point and the cracks" depth, which has the direction sense in the application of projects,The second part of this dissertation is CT , which used the ultrasonic wave running through the tested-substance to get arriving-time of the ultrasonic wave, then inverse the image This dissertation drawed one CT program which can well present the different little cells ultrasonic wave velocity profiles of the substance, thereby to diagnose the quality of the part of the tested-substance, CT has the better using foreground..

在混凝土结构的施工及使用过程中，由于受其自身及外界各种因素的影响，常常会产生一些缺陷，对结构物的承载能力和耐久性造成严重影响，采用无损检测技术进行质量检测和健康诊断，这对混凝土结构开展安全、稳定性评估以及病害隐患治理研究具有重要意义。本论文主要针对大体积混凝土结构缺陷的检测方法展开研究工作，重点讨论了超声波法检测混凝土结构裂缝的基本原理和方法及其特点、适用范围，运用动力有限元数值模拟其检测过程，探讨了有裂缝缺陷的混凝土结构在脉冲荷载作用下弹性波的传播及其变化特征，研究了不同裂缝深度下首波相位变化规律，得出了反转临界点与裂缝深度之间的关系，这对实际工程应用具有指导意义。声波CT是一种新的无损检测技术，它是利用声波穿透被检测体获取声波接收时间，来进行计算机反演成像的技术。本文利用直射线法编制了层析成像程序，能较好地呈现被检测物体各微小单元的声波速度分布图像，从而对检测体的质量状况作出诊断评估，具有较好的应用发展前景。

This one mode pays close attention to network credence foundation of the businessman very much.

这一模式非常关注商人的网络信用基础。

Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.

扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。