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为了提高固体火箭发动机系统的动态交互能力,方便用户直观地了解固体火箭发动机的内部结构,结合CATIA强大的三维建模能力,完成了该系统中最重要的三维参数化设计;以VC++为编程环境,运用CATIA自动化对象编程(V5 Automation)提供的二次开发接口,实现了固体火箭发动机系统中的三维绘图模块,同时介绍了两种在VC框架内动态显示CATIA三维模型的方法;实践证明,该系统能够快速的确定固体火箭发动机外形尺寸、标志量等设计参数,为固体火箭发动机的初步设计提供有效的帮助。 相似文献
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本文讨论型为2^nu^1的有对称正交侣的带洞自正交拉丁方(HSOLSSOM(2^nu^1))的谱。证明当n≤9时,HSOLSSOM(2^nu^1)存在的充分必要条件是u为偶数且n≥3u/2+1;当n≥263时,若u为偶数且n≥2(u-2),则HSOLSSOM(2^nu^1)存在。 相似文献
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本文计算了B_2型有限辛群Sp(4,11)的Cartan不变量矩阵C=(c_((λμ)~((1)))_(λμ∈X_1(Y)). 相似文献
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Shengguo Lu Yuwang Han Xujia Duan Fang Luo Lingyan Zhu Shuang Li He Huang 《Applied biochemistry and biotechnology》2013,171(3):731-743
Supplementation with acetate under low levels was used as a novel approach to control the morphological development of Klebsiella pneumoniae aimed to improve 1,3-propanediol (1,3-PD) production. A full range of morphological types formed from rod shape to oval shape even round shape in response to different concentrations of acetate. The cell growth and 1,3-PD productions in the shake flasks with 0.5 g/L acetate addition were improved by 9.4 and 28.37 %, respectively, as compared to the control, while the cell became shorter and began to lose its original shape. The cell membrane penetration by acetate was investigated by the biomimetic vesicles, while higher concentration of acetate led to more moderate colorimetric transitions. Moreover, the percentage composition of unsaturated fatty acid (UFA) was increased as well as the increased concentrations of acetate, whereas higher UFA percentage, higher fluidity of bacterial cell membrane. 相似文献
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ABSTRACT All the 62 monomial elements in the canonical basis B of the quantized enveloping algebra for type A 4 have been determined in Hu et al. (2003). According to Lusztig's idea (Lusztig, 1992), the elements in the canonical basis B consist of monomials and linear combinations of monomials (for convenience, we call them polynomials). In this note, we compute all the 144 polynomial elements in one variable in the canonical basis B of the quantized enveloping algebra for type A 4 based on our joint note Hu et al. (2003). We conjecture that there are other polynomial elements in two or three variables in the canonical basis B, which include independent variables and dependent variables. Moreover, it is conjectured that there are no polynomial elements in the canonical basis B with four or more variables. 相似文献
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发动机图形绘制与性能计算是火箭设计的关键步骤,通过对固体火箭发动机设计过程的分析,提出CATIA参数化图形绘制技术;以单孔管状装药发动机为例,建立了发动机燃烧室与喷管模型,在VC环境下利用CATIA Automation二次开发技术实现了燃烧室与喷管参数化设计,完成了两者装配与动态显示;利用Matcom实现内弹道压力时间曲线计算,发射段轨道分析;最后完成系统软件编制;实际使用情况表明,使用该软件可快速构造发动机,进行全面的性能分析,为固体火箭发动机方案论证与初步设计提供了有力的工具。 相似文献
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在风浪流的作用下,海洋浮式结构物将带动悬链线立管在水中作周期性往复运动,从而在立管运动方向上产生相对振荡来流,这种振荡来流将激励立管悬垂段发生“间歇性” 的涡激振动. 在海洋工程水池中对一个4m 长的立管微段进行模型试验研究,以探索相对振荡来流作用下立管涡激振动产生的机理及其发展的物理过程. 试验通过振荡装置带动模型作正弦运动来模拟不同最大约化速度URmax、不同KC(Keulegan-Carpenternumber)的相对振荡来流,利用光纤应变片测量立管涡激振动响应. 结合模态分析方法处理试验数据得到位移响应时历,继而提出相对振荡来流下柔性立管涡激振动发展的3 个阶段:建立阶段、锁定阶段以及衰减阶段. 并进一步总结了最大约化速度URmax,KC 对涡激振动发展过程的影响规律. 最终获得不同最大约化速度URmax下,涡激振动各发展阶段随KC 所占时间分布比例图. 相似文献
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