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WAVE INDUCED OSCILLATORY AND STEADY FLOWS IN THE ANNULUS OF A CATHETERIZED VISCOELASTIC TUBE

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Journal of Hydrodynamics 2010年第5期22卷 605-617页

作者： NG Chiu-On chang yin-Yee Department of Mechanical Engineering The University of Hong Kong

A perturbation analysis based on equations of motion in Lagrangian form is presented for the oscillatory and time-mean viscous flows induced by a propagating wave of small amplitude in an annulus with a viscoelastic outer wall. Owing to the steady streaming effect, the existence of a catheter in a blood vessel brings in an additional steady pressure gradient, a correction to that predicted by the linear theory, and an additional steady shear stress, which may increase the possibility of hemolysis of red blood cells.

关键词： annulus flow steady streaming catheterized artery

A new source extraction algorithm for optical space debris observation

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Research in Astronomy and Astrophysics 2013年第5期13卷 604-614页

作者： Rong-Yu Sun chang-yin Zhao Purple Mountain Observatory Chinese Academy of Sciences Key Laboratory of Space Object and Debris Observation Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences

Specific challenges arise in the task of real-time automatic data reduction of optical space debris observations. Here we present an automatic technique that optimally detects and measures the sources from images of optical space debris ob- servations. We show that highly reliable and accurate results can be obtained on most images produced by our specific sensors, and due to optimizations, the whole pipeline works fast and efficiently. Tests demonstrate that the technique performs better than SExtractor from the point of view of fast and accurate detection, therefore it is well suited for data reduction of optical space debris observations.

关键词： techniques: image processing -- space vehicles -- astrometry

Improved astrometry of space debris with image restoration

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Research in Astronomy and Astrophysics 2014年第8期14卷 992-1000页

作者： Rong-Yu Sun chang-yin Zhao Key Laboratory of Space Object and Debris Observation Chinese Academy of Sciences Purple Mountain Observatory Chinese Academy of Sciences

In order to implement an observing strategy, image degradation that occurs during optical observation of space debris is ineluctable and has distinct characteris- tics. Image restoration is presented as a way to remove the influence of degradation in CCD images of space debris, based on assumed PSF models with the same F-WHM as images of the object. In the process of image restoration, the maximum entropy method is adopted. The results of reduction using observed raw CCD images indi- cate that the precision in estimating positions of objects is improved and the effects of degradation are reduced. Improving the astrometry of space debris using image restoration is effective and feasible.

关键词： techniques image processing -- space vehicles -- astrometry -- methods data analysis

Sufficient and Necessary Condition of Admissibility for Fractional-order Singular System

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自动化学报 2013年第12期39卷 2160-2164页

作者： YU Yao JIAO Zhuang SUN chang-yin School of Automation Electrical Engineering University of Science and Technology Beijing Beijing 100083 China Key Laboratory of Advanced Control of Iron and Steel Process Ministry of Education Beijing 100083 China Beijing Institute of Elec- tronic System Engineering Beijing 100854 China

这份报纸与顺序为部分顺序的单个系统集中于考虑条件吗？(0， 1 ) 。整齐的定义，没有推动并且考虑被给第一，然后，为部分顺序的单个系统的考虑的一个足够、必要的条件被建立。一个数字例子被包括说明建议条件。

关键词：奇异系统分数阶充要条件可容许充分必要条件

Asymptotic analysis for transmission capacity of wireless Ad-hoc networks

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The Journal of China Universities of Posts and Telecommunications 2011年第3期18卷 22-26页

作者： CHEN chang-hai yin chang-chuan YUE Guang-xin Key Laboratory of Universal Wireless Communications Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 China

This article puts forward a new solution to the bound of the outage probability and transmission capacity of Ad-hoc networks. For the proofs of the upper and lower bounds are too complex, a much easier way is introduced to get the same results, and by using Taylor series, the asymptotic bound is derived. By comparing with the simulation results, we found that the asymptotic bound is sufficient accurate when the network parameters are selected properly, and is tighter than the upper and lower bounds.

关键词： Ad-hoc transmission capacity lower and upper bounds asymptotic bound

A NEW CONSTRAINTS IDENTIFICATION TECHNIQUE-BASED QP-FREE ALGORITHM FOR THE SOLUTION OF INEQUALITY CONSTRAINED MINIMIZATION PROBLEMS

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Journal of Computational Mathematics 2006年第5期24卷 591-608页

作者： chang-yin Zhou Guo-ping He Yong-li Wang Department of Mathematics Shanghai Jiao Tong University Shanghai 200240 China College of Information Science and Engineering Shandong University of Science and Technology Qingdao 266510 China College of Information Science and Engineering Shandong University of Science and Technology Qingdao 266510 China

In this paper, we propose a feasible QP-free method for solving nonlinear inequality constrained optimization problems. A new working set is proposed to estimate the active set. Specially, to determine the working set, the new method makes use of the multiplier information from the previous iteration, eliminating the need to compute a multiplier function. At each iteration, two or three reduced symmetric systems of linear equations with a common coefficient matrix involving only constraints in the working set are solved, and when the iterate is sufficiently close to a KKT point, only two of them are involved. Moreover, the new algorithm is proved to be globally convergent to a KKT point under mild conditions. Without assuming the strict complementarity, the convergence rate is superlinear under a condition weaker than the strong second-order sufficiency condition. Numerical experiments illustrate the efficiency of the algorithm.

关键词： QP-free method Optimization Global convergence Superlinear convergence,Constraints identification technique.

Robust Attitude Decentralized Tracking Control for a 3-DOF Helicopter with Unknown Input Time-delay

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Robust Attitude Decentralized Tracking Control for a 3-DOF H...

Effects of Magnetic Fields on Neutrino-dominated Accretion Model for Gamma-ray Bursts

第25届中国控制与决策会议

作者： Yao Yu chang-yin Sun School of Automation & Electrical Engineering University of Science and Technology Beijing Key Laboratory of Advanced Control of Iron and Steel Process Ministry of Education

ISBN: (纸本)9781467355339

Robust attitude decentralized tracking control problem for a 3-DOF helicopter is investigated. The model of the 3-DOF helicopter is described as a MIMO strict-feedback form system with unknown parameters, bounded disturbances, nonlinear uncertain coupling effects and unknown input-delay. A new design method based on signal compensation technique and back-stepping strategy is proposed. Based on the signal compensation method, at each backstepping design step, a robust controller consists of a nominal controller and a robust compensator. Robust practical tracking stability condition is derived in terms of linear matrix inequalities （LMIs）. Experimental results demonstrate the effectiveness of the proposed control strategy.

关键词： Backstepping robust tracking linear decentralized controller input time-delay.

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Chinese Journal of Astronomy and Astrophysics 2007年第5期7卷 685-692页

作者： Yi Xie chang-yin Huang Wei-Hua Lei Department of Physics Huazhong University of Science and Technology Wuhan 430074 School of Physics and Information Engineering Shanxi Normal University Linfen 041004

Many models of gamma-ray bursts suggest a common central engine; a black hole of several solar masses accreting matter from a disk at an accretion rate from 0.01 to 10 M⊙s^-1, the inner region of the disk is cooled by neutrino emission and large amounts of its binding energy are liberated, which could trigger the fireball. We improve the neutrino- dominated accreting flows by including the effects of magnetic fields. We find that more than half of the liberated energy can be extracted directly by the large-scale magnetic fields in the disk, and it turns out that the temperature of the disk is a bit lower than the neutrino-dominated accreting flows without magnetic field. Therefore, the outflows are magnetically-dominated rather than neutrino dominated. In our model, the neutrino mechanism can fuel some GRBs （not the brightest ones）, but cannot fuel X-ray flares. The magnetic processes （both BZ and electromagnetic luminosity from a disk） are viable mechanisms for most of GRBs and their following X-ray flares.

关键词： magnetic fields -- accretion, accretion disks-- neutrinos -- gamma rays bursts

A Convenient Method for Chlorination in Allylic Position

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Chemical Research in Chinese Universities 2005年第2期21卷 169-171页

作者： WANGXin-yan SHIHong-chang CHENGang HONGXiao-yin XUShou-yi DepartmentofChemistry TsinghuaUniversityBeijing100084P.R.China

A convenient method for the chlorination in allylic position was developed by using the aqueous solution of sodium hypochlorite(2%_5% active chlorine) and an acid as chlorination reagent in a diphase system. The method has the advantage of cheap reagents, mild reaction conditions and good yields. The quantity and the feeding rate of the chlorination reagent can be controlled easily. The method is particularly suitable for the chlorination in laboratories.

关键词： Chlorination Allylic position Sodium hypochlorite Diphase system