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Liu M.,Ordnance Engineering College | Sun Q.,Ordnance Engineering College | Jiang Z.,Wuhan Ordnance Noncommissioned Officers Academy
Zhongguo Jixie Gongcheng/China Mechanical Engineering | Year: 2013

The micro-magnetic fixed knot which did not depend on the outer magnetic field formed near the defects, because the domain wall in the ferro-magnets was pinned by the defects. The singular distribution of magnetizing field in the micro-magnetic fixed knot near the defects was calculated by the method of minimum energy form micro-magnetics analysis. Defect detection can be realized according to the distribution characteristics and what proposed herein provides a theoretical basis for defect micro-magnetic defection. Source

Zhao B.,CAS Xian Institute of Optics and Precision Mechanic | Zhao B.,University of Chinese Academy of Sciences | Duan K.,CAS Xian Institute of Optics and Precision Mechanic | Liu Y.,Wuhan Ordnance Noncommissioned Officers Academy | Zhao W.,CAS Xian Institute of Optics and Precision Mechanic
Optics Communications | Year: 2010

By using a novel mutual injection technique, phase-locking and coherent combining of two high-power all-fiber lasers are realized and experimentally demonstrated. Steady interference strips with high visibility of 46% are observed. The coherent combined 407 W CW output power with a power-combining efficiency of up to 98% is obtained. The laser array works well with excellent stability. In the long time of high-power operation no thermal distortions or damages are observed. The proposed technique can be used to further scale up the coherent combined output power of high-power fiber lasers. © 2010 Elsevier B.V. All rights reserved. Source

Wei G.,Shijiazhuang Mechanical Engineering College | Li K.,Shijiazhuang Mechanical Engineering College | Li K.,Wuhan Ordnance Noncommissioned Officers Academy | Pan X.,Shijiazhuang Mechanical Engineering College | And 2 more authors.
Gaodianya Jishu/High Voltage Engineering | Year: 2014

For protecting sensitive circuits in shielded enclosures, we analyzed the enclosures enhancement effect of field intensity using the software CST. Then we verified the simulation results though experiments in a homemade experimental system composed of a vector network analyzer, power amplifiers, a giagahertz transverse electromagnetic chamber, and pulsed electromagnetic field measuring probes, etc. Lastly we theoretically analyzed the mechanism of the field enhancement, and the influences of the aperture shape, the electromagnetic wave's polarization direction, the position in cavity, and the absorbing material loaded on the enhancement. It is shown that the simulation agrees with the experiment results. The field enhancement effect of aperture is affected by the enclosure's surface current, the aperture resonance, and the enclosure resonance. The effect is more remarkable if the aperture is rectangular, compared with square or circular apertures. For different polarization directions of the electric field, the electric field perpendicular to the long side of rectangular aperture results in the strongest enhancement effect. The enhancement effect strengthens with decreasing distance to the aperture when the frequency is below its minimum resonant value. Moreover, adding absorbing materials can fairly weaken the enhancement effect at the center of the enclosure. The results can be a theoretic basis for electromagnetic compatibility designs and protections for shielded enclosures with apertures. Source

Shen R.-F.,Ordnance Engineering College | Zheng H.-Q.,Ordnance Engineering College | Jin H.-W.,Academy of Equipment Command and Technology | Kang H.-Y.,Ordnance Engineering College | Dong Z.-W.,Wuhan Ordnance Noncommissioned Officers Academy
Zhendong Ceshi Yu Zhenduan/Journal of Vibration, Measurement and Diagnosis | Year: 2011

In the load change test, the vibration signals are measured on a two-level gearbox testbed. For coping with non-stationary signals effective, wavelet packet is used for obtaining a feature vector (values of condition attribute). For coping with noise data effective, variable precision rough set (VPRS) theory is introduced in the fault diagnosis of the gear, and a kind method of condition attribute reduction is presented. Firstly, continuous attributes are discretized. Then, the set of M is defined, and varying values of β (right ratio of classification) are selected according to the reality, and the quality of approximation classification of VPRS is utilized to carry through condition attribute reduction and contrasted its result with the reduction result coming from data (including noise data). Finally, a practical example in the gear shows the validity and practicability of the algorithm. Source

Mao G.,China University of Technology | Wu Z.,China University of Technology | He Q.,China University of Technology | He Q.,Wuhan Ordnance Noncommissioned Officers Academy | And 5 more authors.
Applied Surface Science | Year: 2011

We investigated the annealing effect on solution processed small organic molecule organic films, which were annealed with various conditions. It was found that the densities of the spin-coated (SC) films increased and the surface roughness decreased as the annealing temperature rose. We fabricated corresponding organic light emitting diodes (OLEDs) by spin coating on the same annealing conditions. The solution processed OLEDs show the considerable efficiency and stability, which were prior or equivalent to the vacuum-deposited (VD) counterparts. Our research shows that annealing process plays a key role in prolonging the lifetime of solution processed small molecule OLEDs, and the mechanism for the improvement of the device performance upon annealing was also discussed. © 2011 Elsevier B.V. All rights reserved. Source

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