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971.
Safety evaluation and the static-dynamic coupling analysis of counter-arched slab in plunge pool 总被引:1,自引:0,他引:1
The stability of plunge pool slab of drainage structure is crucial to energy dissipation, but the working conditions of counter-arched
slab are very complex and its stress procedure is considerably nonlinear and coupling. Therefore, a nonlinear static and dynamic
coupling method to analyze the counter-arched slab configuration is put forward, which can reflect the coupling of dynamic
loads, slab, anchor bars, groundwork and abutment as well as the dynamic procedure of instability. Various nonlinear factors
and static-dynamic coupling are taken into consideration, and the working conditions, stress mechanism, dynamic instability
procedure and influential instability factors are revealed. The proposed method thus provides a comprehensive safety evaluation
method of plunge pool, which further provides an important theoretical basis for engineering design of counter-arched slab
in plunge pool.
Supported by the National Science Fund for Distinguished Young Scholars (Grant No. 50725929) and the National Natural Science
Foundation of China (Grant Nos. 50539060, 50679052, 50779044) 相似文献
972.
The main goal of this paper is to construct an efficient reduced-order model (ROM) for unsteady aerodynamic force modeling.
Balanced truncation (BT) is presented to address the problem. For conventional BT method, it is necessary to compute exact
controllability and observability grammians. Although it is relatively straightforward to compute these matrices in a control
setting where the system order is moderate, the technique does not extend easily to high order systems. In response to the
challenge, snapshots-BT (S-BT) method is introduced for high order system ROM construction. The outline idea of the S-BT method
is that snapshots of primary and dual system approximate the controllability and observability matrices in the frequency domain.
The method has been demonstrated for 3 high order systems: (1) unsteady motion of a two-dimensional airfoil in response to
gust, (2) AGARD 445.6 wing aeroelastic system, and (3) BACT (benchmark active control technology) standard aeroservoelastic
system. All the results indicate that S-BT based ROM is efficient and accurate enough to provide a powerful tool for unsteady
aerodynamic force modeling. 相似文献
973.
Fractal model of lightning channel for simulating lightning strikes to transmission lines 总被引:2,自引:0,他引:2
How to accurately evaluate the direct-strike lightning protection is one of the key issues in the design of transmission lines.
In this paper, three important issues in applying the fractal simulation to the lightning protection of transmission lines
were discussed, including the criteria and implementation of upward leader inception, the connection with the magnitude of
lightning current, and the calculation and control of fractal dimensions. Then we conducted the simulation iterately, leading
to statistical results, which indicate that even if the transmission line satisfies the perfect shielding condition, shielding
failure fault remains possible. Furthermore, we calculated the shielding failure fault rates of an EHV line with different
ground obliquities and distribution of strike points over the interval between two neighboring towers along a UHV-DC line
to find out the weak point of transmission-line lightning protection. This work provides a promising approach for improving
the lightning protection property of transmission lines by optimizing the configuration of shielding wires and phase or pole
conductors. 相似文献
974.
Based on Al induced crystallization (AIC) method, influences of different material structures on formation and characteristics of ploy-silicon thin films were studied and optimized. Al-Si films on glass with different structures (Si/Al/Glass, Al/Si/Glass, Si/Al/…/Si/Al/Glass) were deposited on glass substrates by sputtering method. All samples were annealed for MIC with varied time processes under 500℃ N2 environment. X-ray diffraction test and scanning electron microscope were adopted to characterize cryst... 相似文献
975.
DongJie Guo HaiTao Ding Haiju Wei Qingsong He Min Yu ZhenDong Dai 《中国科学E辑(英文版)》2009,52(10):3061-3070
This paper reports a new technique to fabricate an ion-exchange polymer-metal composite (IPMC) actuator. This technique is based on a hybrid organic-inorganic composite membrane. In the fabrication course, silica oxide particles, prepared from hydrolysis of tetraethyl orthosilicate in situ with sol-gel reaction, co-crystallize with perfluorosulfonate acid (PFSA) ionomer. Attenuated total reflectance fourier transform infrared spectroscopy (ATR-FTIR) analyses demonstrate that a highly water-saving hybrid mem... 相似文献
976.
Andre SULPICE Jean-Louis SOUBEYROUX Christophe VERWAERDE Gia Ky HOANG 《中国科学E辑(英文版)》2009,52(10):3071-3075
Two sets of internal-Sn Nb3Sn superconducting strands were fabricated through RRP method, one with 2 wt% of Ti alloyed in Sn core and the other just pure Sn. Four reaction temperatures of 650℃, 675℃, 700℃ and 725℃ and 128 h duration were applied for A15 phase formation heat treatment after Cu-Sn alloying procedure of 210℃/50 h + 340℃/25 h. For the heat-treated coil samples, transport non-Cu JC was examined through standard 4-probe technique and phase microstructure was observed by means of Field Emission Sc... 相似文献
977.
In order to restrain the mid-spatial frequency error in magnetorheological finishing (MRF) process, a novel part-random path is designed based on the theory of maximum entropy method (MEM). Using KDMRF-1000F polishing machine, one flat work piece (98 mm in diameter) is polished. The mid-spatial frequency error in the region using part-random path is much lower than that by using common raster path. After one MRF iteration (7.46 min), peak-to-valley (PV) is 0.062 wave (1 wave =632.8 nm), root-mean-square (RM... 相似文献
978.
Research on indoor experimentation of range SAL imaging system 总被引:1,自引:0,他引:1
GUO Liang XING MengDao ZHANG Long TANG Yu & BAO Zheng State Key Laboratory of Radar Signal Processing Xidian University Xi’an China Xi’an Polytechnic University Xi’an 《中国科学E辑(英文版)》2009,52(10):3098-3104
By means of advantages of both SAR and lidar, the combination of the techniques of (inverse) synthetic aperture and lidar makes it possible to obtain high resolution 2-D image. In this paper, an indoor experimental system of inverse synthetic aperture lidar imaging is given and a processing approach is presented. The given system is in the mode of lidar system with separated receiver and transmitter, which can effectively eliminate the jamming from the lens or/and the intersection between two optic fibers. ... 相似文献
979.
YUAN Jing HE ZhengJia ZI YanYang & LIU Han State Key Laboratory for Manufacturing Systems Engineering School of Mechanical Engineering Xi’an Jiaotong University Xi’an China Shanghai Baosteel Industry Inspection Corporation Baosteel Group Corporation Shanghai 《中国科学E辑(英文版)》2009,52(10):2801-2809
Fault diagnosis of rolling mills, especially the main drive gearbox, is of great importance to the high quality products and long-term safe operation. However, the useful fault information is usually submerged in heavy background noise under the severe condition. Thereby, a novel method based on multiwavelet sliding window neighboring coefficient denoising and optimal blind deconvolution is proposed for gearbox fault diagnosis in rolling mills. The emerging multiwavelets can seize the important signal proce... 相似文献
980.
ZhenXia Wang XinNian Li CuiLan Ren ZhenZhong Yong JianKang Zhu WenYun Luo XiaoMing Fang 《中国科学E辑(英文版)》2009,52(11):3215-3218
The experimental investigations on the interaction between Ag-nanocrystal particles (Ag-NCPs) and carbon nanotubes (CNTs)
in Ag-nanocrystal particles/carbon nanotubes (Ag-NCPs/CNTs) hybrid structures were reported. The growth of Ag-NCPs on multiwalled
carbon nanotubes (MWCNTs) was carried out by thermal evaporation deposition. High-resolution transmission electron microscopy
and X-ray diffraction analyses revealed that Ag-NCPs had the crystal lattice feature of face-centered cube (fcc). The growth
of Ag-NCPs on MWCNTs induced the cross-section deformation of MWCNT. The experimental results also showed that the synthesized
Ag-NCPs/CNTs hybrid structure appeared as quasi-one dimensional nanowires containing the Ag-NCP/CNT hetero-junction. There
was local cross-section deformation on MWCNTs at the interface of hetero-junction. These results involve the important topic
about fundamental and practical studies for structure of MNCPs on CNTs and also find clues to further research of Ag nanocrystal
growing on MWCNTs and related Ag-CNT interaction. 相似文献