Showing 1 to 10 of 360 matching Articles
Results per page:
Export (CSV)
By
Xialing, Guan
In China, a multipurpose verification system as a first phase of our ADS program consists of a low energy accelerator (150 MeV/3 mA proton LINAC) and a swimming pool light water subcritical reactor. In this paper the activities of HPPA technology related to ADS in China, which includes the intense proton ECR source, the RFQ accelerator and some other technology of HPPA, are described.
more …
By
Shen, Yunwen; Liu, Mengjun; Dong, Haijun
In some mechanical nonlinear systems, the transient motion will be undergoing a very long process and the attractorbasin boundaries are so complicated that some difficulties occur in analyzing the system global behavior. To solve this problem a mixed cell mapping method based on the point mapping and the principle of simple celll mapping is developed. The algorithm of the mixed cell mapping is studied. A dynamic model of a gear pair is established with the backlash, damping, transmission error and the timevarying stiffness taken into consideration. The global behaviors of this system are analyzed. The coexistence of the system attractors and the respective attractorbasin of each attractor with different parameters are obtained, thus laying a theoretical basis for improvement of the dynamic behaviors of gear system.
more …
By
Ma, Jianbo; Xu, Jin; Cao, Zhibin
3 Citations
In this paper a method of autonomous orbit determination using star sensor is studied. By building relatively consummate dynamical models which simulate attitude motion of satellite and observation from satellite to background stars, the simulant computation of this method is executed, and it is shown that the method of autonomous orbit determination is feasible. Academic and calculation analyses have been done for the relation between the direction of star sensor with respect to statellitebody coordinate system and the accuracy of autonomous orbit determination.
more …
By
Zhang, Tongjie; Song, Guoxuan
Conclusion
We have explored a model for the formation of giant molecular clouds through accretion of smaller clouds; the star disc is assumed to be rigidly rotating in this model. The main results are:
(1)
The aggregates consist mainly of the neighbouring clouds whose collision was induced by the velocity dispersion. In this model aggregates take a shorter time to form compared to the model which includes differential rotation, although the aggregates tend to be less massive.
(2)
By the same token, the mass of these aggregates does not increase further. The inclusion of differential rotation would have allowed for the possibility of distinct aggregates colliding amongst themselves to form larger aggregates.
more …
By
Bao, S. D.; Ai, G. X.; Zhang, H. Q.
24 Citations
We compute the signs of two different current helicity parameters (i.e., &#x03B1;_{best} andH_{c}) for 87 active regions during the rise of cycle 23 The results indicate that 59% of the active regions in the northern hemisphere have negative &#x03B1;_{best} and 65% in the southern hemisphere have positive. This is consistent with that of the cycle 22. However, the helicity parameterH_{c}shows a weaker opposite hemispheric preference in the new solar cycle. Possible reasons are discussed.
more …
By
Zhang, Dongming; Luo, Jisheng; Zhou, Heng
2 Citations
Based on the theoretical model for a single coherent structure in the wall region of a turbulent boundary layer, we studied the interaction of two coherent structures by direct numerical simulation in order to explain the mechanism for the formation of lowspeed streaks.
more …
By
Huang, Jianguo; Han, Jianwei
A key point in SEE (Single Event Effect) simulation experiment is how to calculate the equivalent LET (Linear Energy Transfer) for laser pulse. In this paper, the calculation method considering the influences of nonlinear absorption in semiconductor, reflection and refraction on device surface and other factors is presented. Simultaneously an instance of calculation is provided, with the result in good agreement with the SEU (Single Event Upset) threshold measured by heavy ions.
more …
By
Liu, Chun; Zhang, Laibin; Wang, Zhaohui
Condition monitoring and life prediction of the vehicle engine is an important and urgent problem during the vehicle development process. The vibration signals that are closely associated with the engine running condition and its development trend are complex and nonlinear. The chaos theory is used to treat the nonlinear dynamical system recently. A novel chaos method in conjunction with SVD (singular value decomposition) denoising skill are used to predict the vibration time series. Two types of time series and their prediction errors are provided to illustrate the practical utility of the method.
more …
By
Chen, Zhenpeng; Zhang, Rui; Sun, Yeying; Liu, Tingjin
Show all (4)
The error propagation features with Rmatrix model fitting^{7}Li,^{11}B and^{17}O systems have been researched systematically. Some laws of error propagation have been revealed, an experience formula for describing standard error propagation has been established, and the most possible error range for evaluated standard cross section of^{6}Li (n, α),^{10}B (n, α) and^{10}B (n, α_{1}) has been determined.
more …
