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塞式喷管底部压强模型

推进技术 2003年第4期24卷 330-333页

作者：李军伟刘宇北京航空航天大学宇航学院北京100083

为了工程计算的需要,首先分析了已有的底部压强计算模型,找出了影响底部压强的主要因素,即塞锥出口截面的压强、马赫数,塞锥出口倾角和底部二次流流率;然后根据数值计算得到的底部压强和冷流实验测出的底部压强,分别拟合底部压强与塞锥... 详细信息

为了工程计算的需要,首先分析了已有的底部压强计算模型,找出了影响底部压强的主要因素,即塞锥出口截面的压强、马赫数,塞锥出口倾角和底部二次流流率;然后根据数值计算得到的底部压强和冷流实验测出的底部压强,分别拟合底部压强与塞锥出口压强和马赫数的关系式,底部压强与塞锥倾角的关系式,底部压强与底部二次流流率的关系式,最后把这些关系式几何平均得到了所有这些因素与底部压强的关系式。与实验数据比较,该拟合公式不但很好地反映了底部压强的变化规律,而且能够满足工程估算的需要。

关键词：火箭发动机塞式喷管底部压力曲线求律法

MULTI-MODE OF VORTEX-INDUCED VIBRATION OF A FLEXIBLE CIRCULAR CYLINDER

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Journal of Hydrodynamics 2011年第4期23卷 483-490页

作者： XIE Fang-fang DENG Jian ZHENG Yao school of aeronautics and astronautics Zhejiang University Hangzhou 310027 China

The vortex-induced vibration of a flexible circular cylinder is investigated at a constant Reynolds number of 1000. The finite-volume method on moving meshes is applied for the fluid flow, and the Euler-Bernoulli beam theory is used to model the dynamic response of a flexible cylinder. The relationship between the reduced velocity and the amplitude response agrees well with the experimental results. Moreover, five different vibrating modes appear in the simulation. From the comparisons of their vortex structures, the strength of the wake flow is related to the exciting vibrating mode and different vortex patterns arise for different vibrating modes. Only 2P pattern appears in the first vibrating mode while 2S-2P patterns occur in the other vibrating modes if monitoring at different sections along the length of the cylinder. The vibration of the flexible cylinder can also greatly alter the three-dimensionality in the wake, which needs further studies in our future work, especially in the transition region for the Reynolds number from 170 to 300.

关键词： multi-mode Vortex-Induced Vibration (VIV) three-dimensional instability flexible cylinders Euler-Bemoulli beam

Noise helped manifestation of intrinsic frequency:A case study in the mesoscopic hormone signaling system

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Progress in Natural Science:Materials International 2009年第10期19卷 1209-1214页

作者： Lin Ji a,,Yuanyuan Zhang a,Xiufeng Lang b,Wenxiang Hu a,Qianshu Li c a Department of Chemistry,Capital Normal univ.rsity,Beijing 100048,china b school of Science,Beijing univ.rsity of aeronautics and astronautics,Beijing 100191,china c The Institute for Chemical Physics,Beijing Institute of technology,Beijing 100081,china [a]Department of Chemistry Capital Normal University Beijing 100048 China [b]school of Science Beijing University of Aeronautics and Astronautics Beijing 100191 China [c]The Institute for Chemical Physics Beijing Institute of Technology Beijing 100081 China

The selective sustainment of nonlinear systems to signals is of great significance to signal transduction in living *** take hormone signaling as an example,and investigate the sustainment of internal and external *** results prove that signals with "intrinsic frequency",no matter if it is noise induced or external injected,can be selectively sustained by exploiting internal and/or external *** the internal and external noise can optimize the noise-induced signals,and the optimization is rather robust to the disturbance of external signals with other *** results are of significance for weak signal detection and transduction in the presence of external signals.

关键词： Noise Intrinsic frequency Mesoscopic system

Responding Depth of Photocatalytic Activity of TiO_2 Self-assembled Films

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Journal of Materials Science & technology 2004年第4期20卷 472-474页

作者： Weichang HAO, Feng PAN, Tianmin WANG and Shukai ZHENG)Center of Materials Physics and Chemistry, school of Science, Beijing univ.rsity of aeronautics and astronautics, Beijing 100083, chinaDepartment of Materials Science, Lanzhou univ.rsity, Lanzhou 730000, china Ctr. of Mat. Phys. and Chem. Sch. of Sci. Beijing Univ. of Aero. and Astron. Beijing 100083 China Dept. of Mat. Sci. Lanzhou Univ. Lanzhou 730000 China

The electrostatically self-assembly method is getting strategically important to prepare multilayer thin films. With careful choice of component materials, this method should allow for the preparation of multilayer thin films with a variety of excellent technological properties. Ti02/PSS multilayer thin films with ordered structure were prepared by electrostatic self-assembly method. UV-Vis-NIR spectrophotometer, X-ray photoelectron spectroscopy (XPS), and atom force microscopy (AFM) were used to characterize the structure and performance of the multilayer films. Because electrostatically self-assembly method allows molecular-level control over the film composition and thickness, this paper studied the responding depth of photocatalytic activity of Ti02 self-assembled films in detail.

关键词： Responding depth Titanium dioxide Photocatalytic activity Electrostatically self-assembly

移动容迟网络中基于改进随机路点模型的移动连接路由

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吉林大学学报（工学版） 2011年第S1期41卷 297-303页

作者：李晖浙江大学航空航天学院杭州310027

在移动容迟网络中,考虑到稀疏网络节点混存长时间被无效消息占用情况,将移动连接路由算法与倒数计时器和快速缓存释放策略相结合,提出了加速缓存释放的移动连接路由算法,并研究了节点移动速率、通信距离、节点数量、消息有效时间、场景... 详细信息

在移动容迟网络中,考虑到稀疏网络节点混存长时间被无效消息占用情况,将移动连接路由算法与倒数计时器和快速缓存释放策略相结合,提出了加速缓存释放的移动连接路由算法,并研究了节点移动速率、通信距离、节点数量、消息有效时间、场景尺寸等对算法性能的影响。结果表明:该路由算法在保证传输可靠性的前提下能够提高网络的传输效率。

关键词：通信技术移动延迟网络随机路点模型路由缓存释放

ROBUST NONPARAMETRIC REGRESSION BASED ON L_1-NORM AND B-SPLINES

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Systems Science and Mathematical Sciences 1995年第2期8卷 187-192页

作者： SHI Peide(Department of Probability and Statistics, Peking univ.rsity, Beijing 100871,china)ZHANG Zhengjun(school Of Management,Beijing univ.rsity of aeronautics and astronautics,Beijing 100083, china) 北京大学概率统计系北京北京航空航天大学管理学院北京

ＲＯＢＵＳＴＮＯＮＰＡＲＡＭＥＴＲＩＣＲＥＧＲＥＳＳＩＯＮＢＡＳＥＤＯＮＬ＿１－ＮＯＲＭＡＮＤＢ－ＳＰＬＩＮＥＳＳＨＩＰｅｉｄｅ（ＤｅｐａｒｔｍｅｎｔｏｆＰｒｏｂａｂｉｌｉｔｙａｎｄＳｔａｔｉｓｔｉｃｓ，Ｐｅｋｉｎｇ... 详细信息

ＲＯＢＵＳＴＮＯＮＰＡＲＡＭＥＴＲＩＣＲＥＧＲＥＳＳＩＯＮＢＡＳＥＤＯＮＬ＿１－ＮＯＲＭＡＮＤＢ－ＳＰＬＩＮＥＳＳＨＩＰｅｉｄｅ（ＤｅｐａｒｔｍｅｎｔｏｆＰｒｏｂａｂｉｌｉｔｙａｎｄＳｔａｔｉｓｔｉｃｓ，ＰｅｋｉｎｇＵｎｉｖｅｒｓｉｔｙ，Ｂｅｉｊｉｎ...

关键词： B-spline function L1-norm estimator TURBO nonparametric regression

Relation Entropy and Transferable Entropy Think of Aggregation on Group Decision Making

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Systems Science and Systems Engineering 2002年第1期11卷 13-18页

作者： CHENG Qi-yue, QIU Wan-hua, LIU Xiao-feng school of Management, Beijing univ.rsity of aeronautics and astronautics, Beijing 100083, china school of Management Beijing University of Aeronautics and Astronautics Beijing 100083 China

In this paper, aggregation question based on group decision making and a single decision making is studied. The theory of entropy is applied to the sets pair analysis. The system of relation entropy and the transferable entropy notion are put. The character is studied. An potential by the relation entropy and transferable entropy are defined. It is the consistency measure on the group between a single decision making. We gained a new aggregation effective definition on the group misjudge.

关键词： group decision making relation entropy transferable entropy

TWO－LEVEL MULTI－POINT APPROXIMATION METHOD FOR OPTIMUM DESIGN OF COMPLICATED STRUCTURES

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Chinese Journal of aeronautics 1995年第1期8卷 9-16页

作者： Huang Hai Xia Renwei(school of Space Science and technology, Beijing univ.rsity ofaeronautics and astronautics, Beijing, china, 100083)

ＴＷＯ－ＬＥＶＥＬＭＵＬＴＩ－ＰＯＩＮＴＡＰＰＲＯＸＩＭＡＴＩＯＮＭＥＴＨＯＤＦＯＲＯＰＴＩＭＵＭＤＥＳＩＧＮＯＦＣＯＭＰＬＩＣＡＴＥＤＳＴＲＵＣＴＵＲＥＳＨｕａｎｇＨａｉ；ＸｉａＲｅｎｗｅｉ（ＳｃｈｏｏｌｏｆＳｐａ... 详细信息

ＴＷＯ－ＬＥＶＥＬＭＵＬＴＩ－ＰＯＩＮＴＡＰＰＲＯＸＩＭＡＴＩＯＮＭＥＴＨＯＤＦＯＲＯＰＴＩＭＵＭＤＥＳＩＧＮＯＦＣＯＭＰＬＩＣＡＴＥＤＳＴＲＵＣＴＵＲＥＳＨｕａｎｇＨａｉ；ＸｉａＲｅｎｗｅｉ（ＳｃｈｏｏｌｏｆＳｐａｃｅＳｃｉｅｎｃｅａｎｄＴｅｃｈｎ...

关键词： structural design optimization approximation

液体火箭发动机反力式涡轮动叶进口攻角的研究

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推进技术 2002年第5期23卷 383-386页

作者：张国舟俞南嘉魏沫北京航空航天大学宇航学院北京100083 北京丰源机械研究所北京100076

针对高性能分级燃烧(闭式)循环液体火箭发动机用反力式涡轮的特点,对所设计的动叶叶栅S1流面的准三元流气动分析和已有动叶平面叶栅的亚声速风洞试验,研究了反力式涡轮动叶正负攻角对叶栅内的绕流和能量损失的影响。结果表明:对于给定... 详细信息

针对高性能分级燃烧(闭式)循环液体火箭发动机用反力式涡轮的特点,对所设计的动叶叶栅S1流面的准三元流气动分析和已有动叶平面叶栅的亚声速风洞试验,研究了反力式涡轮动叶正负攻角对叶栅内的绕流和能量损失的影响。结果表明:对于给定的来流方向,为得到连续收敛的叶栅几何通道和小的能量损失,动叶应采用正攻角设计。对已有的连续收敛的动叶叶栅,应采用负攻角流入工况,能量损失小。

关键词：反力式涡轮涡轮转子进口攻角液体推进剂火箭发动机