基于速度矩阵法的舰炮多体发射系统动态响应分析

将舰炮多体发射系统简化为若干弹性元件铰接的准弹性模型.应用速度矩阵法进行了各刚体动力学关系的分析与计算,确定了该系统的速度矩阵及角速度矩阵,建立了舰炮多体发射系统6自由度动力学方程,通过Matlab进行矩阵及符号的运算推导,并进行了数值仿真.数值计算得到了舰炮多体发射系统中各刚体的运动规律和受力情况.最后对不同刚度参数下舰炮系统的振动响应进行分析,得到了高低机的扭转刚度与基座舰体间接触刚度的变化对舰炮发射的振动影响规律,为舰炮的结构设计及优化和提高射击稳定性提供了依据.     

拖曳系统飞行仿真

分别采用拖缆的"刚化柔性悬索"和"线性弹簧"模型,建立了拖曳式空中发射重复使用运载器系统的动力学模型,并对拖曳系统在纵向平面内的整个飞行过程,包括起飞、爬升、改平以及平飞,进行了仿真计算,其计算方法是可行的,拖缆采用这两种模型获得的计算结果基本一致,可用于拖曳空中发射重复使用运载器可行性的评价。同时对拖缆采用上述两种模型时,其作用于拖曳飞机和运载器的拉力的大小和方向进行了研究,相互印证了这两种模型的可行性。研究结果表明在拖曳系统这样的多体系统中,上述两种拖缆模型的使用是合适的。     

月球探测车的动力学建模与仿真分析

针对月球的复杂地形环境,利用多体系统动力学的理论,将月球探测车作为一个多刚体系统,对其进行动力学分析,建立了软地面环境下的月球探测车动力学模型.并利用ADAMS软件对所建立的动力学模型进行求解和仿真分析,为月球探测车控制系统的设计与数值计算提供了理论依据.     

甲板上舰载机牵引系统的行驶特性分析

对甲板上飞机有杆牵引系统的行驶特性进行仿真分析.考虑舰船横摇、纵摇和垂荡3个自由度的耦合运动对牵引系统产生的惯性力,建立三自由度时变、非线性牵引车-飞机系统动力学模型.借助Matlab/Simulink以及多体系统动力学软件,研究甲板上牵引系统的行驶特性机理,给出牵引系统在不同海况、负载状况、行驶速度等条件下的表现特征.理论分析和仿真结果表明:海况以及负载是影响舰载机牵引系统行驶特性的主要因素.当系统以不同速度行驶时能够很快地达到稳定状态,即使在侧风扰动后,仍表现出良好的操纵稳定性.     

多刚体系统动力学在锚杆机动力学建模中的应用

为解决多刚体系统在进行动力学建模中存在的结构复杂, 难以进行计算机仿真等问题, 提出运用R W方法对多刚体系统进行动力学建模。通过对锚杆机动力学模型的建立, 列出动力学模型的计算方程式, 通过求解方程式, 得到刚体位行, 与模拟实验进行对比, 可知最大误差小于1%。由此证实了R-W方法在对多刚体系统动力学进行建模时的准确性、 简洁性与优越性。     

载货汽车平顺性多刚体系统动力学建模与仿真

文章根据载货汽车的特点对其模型进行了简化,建立了十一自由度的多刚体系统动力学模型;以卡尔丹角描述载货汽车多刚体系统的姿态,运用多刚体系统动力学建模方法,建立了载货汽车十一自由度平顺性动力学模型及其动力学方程;激励分析中考虑了轮胎径向跳动的影响,采用逆快速傅里叶变换(inverse fast Fourier transform,IFFT)法建立了四轮相关路面随机输入时域模型;在此基础上,利用Matlab的GUI模块开发了载货汽车平顺性时域仿真系统,并以某型号载货汽车为例进行了平顺性时域仿真;最后,通过载货汽车平顺性实验,验证了该系统的仿真结果是准确可靠的。该系统实现了载货汽车多刚体系统的参数化建模与仿真,能有效地对载货汽车平顺性进行性能预测和评估。     

平尾偏转对飞机着陆滑跑性能的影响

为了考察平尾偏转角度对飞机着陆滑跑性能的影响,通过计算流体力学进行气动数据储备,利用多体动力学建模方法,建立了能够反映飞机气动特性随迎角和平尾偏角变化而变化的飞机着陆滑跑动力学模型,在不同的飞机平尾偏转工况下进行了着陆滑跑仿真计算。经过验证,该动力学模型能够较好地反映飞机着陆滑跑时不同平尾偏转角度下动力学特性,仿真结果表明平尾前缘下偏（拉杆）能够有效缩短着陆滑跑距离。     

机载导弹发射动力学建模与虚拟样机仿真

基于导弹在发射导轨上的运动特征,以"捕食者"机载导弹发射系统为物理原形,建立了发射动力学和运动学模型,并应用MSC.ADAMS软件建立导轨发射条件下弹-架系统动力学模型,进行了动力学仿真试验,研究结果表明,理论计算值和仿真结果相符,得到了发射过程中导弹的位置、速度和加速度随时间的变化关系以及导弹与载机分离时对载机位置、速度和加速度的影响规律.     

基于实现预期空战机动的飞机运动模型

在研究空战战术和作战效能时,往往先确定期望的机动动作,继而解算预期动作的飞机动力学参数.针对如何建立既具有准确动力学特性又能适应空战机动研究的空战机动模型的问题,建立了实现预期空战机动的简化飞机动力学模型,用机动过载大小和方向、发动机状态或速度作为机动动作的输入量,较好地将飞行员的机动意图转换成机动控制的输入.同时,考虑飞机的实际限制,确定了飞机六自由度参数,并以飞机刚体六自由度模型为参照进行了机动仿真,比较了仿真结果.结果表明文中模型仿真精度高,简单实用,适用于空战仿真研究.     

含间隙涡旋压缩机转子系统刚柔耦合模型仿真分析

为了提高涡旋压缩机转子系统的精度与可靠性,通过ADAMS和ANSYS建立了含运动副间隙涡旋压缩机转子多刚体及刚柔耦合模型,对动涡盘倾覆下驱动轴承柔性和运动副间隙对转子系统动力学性能的影响进行仿真分析,在此基础上对轴承偏磨区域进行了有限元分析.分析结果表明:运动副间隙下轴承柔性对轴承的位移和速度影响较小,对轴承加速度和碰撞力影响较大;加速度最大值约为多刚性体模型的13.34倍,碰撞力最大值增加2.9倍;排气角后31.29°范围轴承发生偏磨,在滚针的2/7处出现最大应力.仿真结果为涡旋压缩机的设计和动力学行为预测提供分析方法和理论指导.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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