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In this dissertation, periodic impact motions in vibro-impact systems are studied, and the existence and stability of superharmonic periodic impact motions are obtained. The critical bifurcation parameter intervals of superharmonic periodic impact motions are deduced, and numerical simulations are used to verify the results.

中文题名碰振或约束系统的全局分析及稳定性研究副题名外文题名 Studies on global analysis and stability in vibro-impact or constraint systems 论文作者张彦梅导师陆启韶教授学科专业一般力学与力学基础研究领域\研究方向学位级别博士学位授予单位北京航空航天大学学位授予日期2002 论文页码总数95页关键词碰振系统转子系统多体系统碰撞振动馆藏号BSLW /2003 /O322 /1 本论文讨论了碰撞振动系统的周期碰撞运动，得到了超谐周期碰撞运动的存在性和稳定性，推导出亚谐周期运动的临界分岔参数区间，并利用数值模拟进行验证。

Terramechanics concerns studies on the interaction between vehicles and rough terrain in off-road locomotion. The main topics include prediction of vehicle mobility performance, optimum design of mobility systems and soil trafficability evaluation.

地面力学是研究越野行驶中机器与地面相互作用的一门力学学科，包括对机器通过性的预测和评价，行走机构的优化设计以及对地面可行驶性的预测判断等几个方面。

This model can be used in the analysis of the stability of bending-torsionof thin-walled structures and the analysis of ultimate bearing capacity of spatial member structures.

采用本文提出的几何非线性分析力学模型可进行薄壁空间杆系结构的弯扭失稳分析，为实现薄壁杆系结构的极限承载力分析提供了较为精确合理的分析力学模型。

By using wave mechanics , the process of impact driving pile is analyzed,and a mechanics mode of impact driving system which consists of hammer spring cup and pile is established.

应用波动力学分析了冲击沉桩过程，建立了由冲锤、桩帽和桩组成的冲击沉桩系统的力学模型，研究了冲锤重量、桩帽刚度和桩波阻抗对效率的影响，在此基础上，提出了冲锤、桩帽和桩的最佳方案。

Based on the single fiber axisymmetrical and three dimensional models of an aligned short fiber reinforced metal matrix composite, the effect of varied fiber aspect ratio on the mechanical behavior of this composite is analyzed by the elasto-plastic finite element method.

在单向短纤维增强金属基复合材料的单纤维轴对称和单纤维三维细观力学模型的基础上，利用弹塑性有限元分析方法，研究该类复合材料中短纤维长径比的变化对材料整体力学行为的影响。

Cross-dipole Acoustic Logging is the best measurement of the formation wave-slowness,amplitude and attenuation coefficient of the compressional,shear and Stoneley wave types that may occur in array acoustic waveform data.Further more,it has special superiority in the evaluation of shear-wave azimuthally anisotropy.

0引言在柴达木盆地交叉偶极子声波测井主要有以下方面的用途：纵横波、斯通利波的提取，地层各向异性分析和斯通利波渗透性分析，并且可以根据地层岩石动态力学参数的计算方法进行储层动态力学参数的计算和估计，指导工程施工。

At last, ILIF in segment L3-4 and L4-5 is feasible. 2. There are enough operation space for ILIF in L3-4 and L4-5 with the root being retracted gently. And it is feasible to insert a couple transpedicle screws homolaterally. The intertransverse area was too narrow to perform ILIF on L5-S1.3. ILIF provide greater biomechanical stability than TLIF. while there was no significantly different stability between ILIF with homolateral or bilateral pedicle screw fixation. Adequate postoperative stability can be achieved by intertransverse lumbar interbody fusion with homolateral pedicle screw fixation.4. ILIF with transpedicle screws fixation homolaterally was a safe, convenient and effective operation, and less intraspinal complications were occurred of ILIF than TLIF.5. The fusion condition was satisfaction in ILIF group, which was better than TLIF group.

横突间入路腰椎椎体间融合术在L3-4、L4-5节段具有可行性。2、在L3-4、L4-5节段可提供足够的空间行ILIF手术，并可通过同一切口附加椎弓根钉固定，操作安全、简便。L5-S1节段横突间区域较小，操作困难，不适合行ILIF手术。3、ILIF手术术后生物力学稳定性有所下降但优于TLIF手术；ILIF附加同侧椎弓根钉固定与附加双侧椎弓根钉固定生物力学稳定性相当，使用ILIF术式附加侧同椎弓根螺钉固定，可提供较好的即刻稳定性。4、ILIF手术及附加同侧椎弓根钉固定是一种安全、简便、有效的手术方式，在减少椎管内并发症方面具有优势。5、ILIF手术可获得较好的融合率，其融合情况从组织学观察稍好于TLIF手术。

Methods By the datas from measuring 20 cases of dried adult lumbar spine specimens, to design a integer-type of aliform-shape memory alloy intrasegmental fixation instrument, according to the favourable shape-memory ability and the distinct biomechanics-characteristics of nickel-titanium shape memory alloy, then to research its material mechanical property and finite element method analysis.

依据干燥完整的成人腰椎标本相关解剖数据的测量结果，利用镍钛记忆合金良好的形状记忆功能和独特的生物力学特征设计一种整体型翼状腰椎峡部裂记忆合金节段内固定器，并进行材料力学测试和有限元分析。

The fabrication and characterization of microcellular plastics are introduced brietly and the emphasis is placed on the studies on into mechanical properties of microcellular plastics, including some author's work in this field.

对微孔泡沫塑料力学行为的研究文献进行了综述，简单介绍了微孔泡沫塑料的制备和表征方法，重点介绍了微孔泡沫塑料力学性能的研究工作，其中也包括作者近期在该领域的一些工作。

Si alloy thixotropic deformation behavior has been established. Phenomenologically, An internal variable framework effectively combines the microstructure level structural kinetics with the maroscopic flow behavior.

采用自制的半固态合金固液两相区力学性能测试装置进行半固态Al-7.0％Si合金的触变力学性能的研究，建立了半固态Al-7.0％Si合金触变变形行为的幂律模型。

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。