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A new method for position-sensitive measurement of beta surface contamination

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Nuclear Science and Techniques 2017年第2期28卷 49-56页

作者： Yan-Tao Qu Hui Wang Yang Liu Ling Chen Jie Hou Zhe Liu Ji-Zeng Ma Department of Radiation Protection China Institute of Atomic Energy Beijing 102413 China Nuclear and Radiation Safety Center Ministry of Environment Protection Beijing 100082 China Occupational Radiation Protection Unit Radiation Safety and Monitoring Section NSRW IAEA PO Box 1001400 Vienna Austria

In this paper, we propose a new method for position-sensitive measurement of beta surface contamination. With a position-sensitive detector of enlarged sensitive detection area, accurate information of the contamination distribution can be obtained. The positionsensitive detection is based on a large-area plastic scintillator and the wavelength shifting(WLS) fibers and adopts the ‘‘light center of gravity'' method. Optical transmission of the detector is simulated with a preliminary detector model, and feasibility of the detector design and measurement method is evaluated using an experiment *** simulation and experiment results at different beta-ray incident points on the scintillator surface show that there is a polynomial relationship between the average amplitude ratio of the output pulses from the two parallel WLS fibers in the same fiber layer and the relative distance from the incident point to the WLS fiber.

关键词： Beta surface contamination Position-sensitive measurement Wavelength shifting fibers Plastic scintillator

Research on Auto-detection for Remainder Particles of Aerospace Relay Based on Wavelet Analysis

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Chinese Journal of Aeronautics 2007年第1期20卷 75-80页

作者： GAO Hong-liang ZHANG Hui WANG Shu-juan Department of Electrical Engineering Harbin Institute of Technology Harbin 150001 China

Aerospace relay is one kind of electronic components which is used widely in national defense system and aerospace system. The existence of remainder particles induces the reliability declining, which has become a severe problem in the development of aerospace relay. Traditional particle impact noise detection （PIND） method for remainder detection is ineffective for small particles, due to its low precision and involvement of subjective factors. An auto-detection method for PIND output signals is proposed in this paper, which is based on direct wavelet de-noising （DWD）, cross-correlation analysis （CCA） and homo-filtering （HF）, the method enhances the affectivity of PIND test about the small particles. In the end, some practical PIND output signals are analysed, and the validity of this new method is proved.

关键词： aerospace relay remainder particles PIND wavelet analysis

Effect of manganese addition on the microstructure and electromagnetic properties of YIG

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Journal of Rare Earths 2011年第6期29卷 562-566页

作者：王加仟杨建金宇龙丘泰 College of Materials Science and Engineering Nanjing University of Technology Nanjing Institute of Electronic technology

Y3MnxFe4.85–xO12 （x=0, 0.02, 0.04, 0.06, 0.08 and 0.1） garnet ferrites （YMnIG） were prepared by conventional solid-state reaction method in air atmosphere. The effect of Mn addition on the microstructure and electromagnetic properties of YIG were investigated by means of techniques such as X-ray diffraction, scanning electron microscopey, network analyzer, hysteresigraph, magnetic balance and electron paramagnetic resonance spectrometry. Pure garnet phase of Y3Fe5O12 was identified for all the samples, except for minor YFeO3 phase appearing in the sample with x=0.06. The addition of Mn showed little influence on the dielectric constant of YIG, which varied between 14.2 and 14.5. Substituting Mnn＋ for Fen＋ in YIG decreased the total amount of Fe ions, inhibited the reduction of Fe3＋ and promoted the grain growth of garnet phase, which led to the decrease in dielectric loss and coercivity. Because the amount of Mn3＋ ions in octahedral sites in- creased with Mn concentration, the saturation magnetization showed a slight decrease firstly and then increased notably. The addition of Mn could also increase the remanence ratio of YIG ferrites by decreasing the magnetostriction constant λ111. Therefore, doping Mn into YIG fer- rites with proper quantity could improve electromagnetic properties of YIG significantly. The YMnIG ferrite with x=0.08, i.e., Y3Mn0.08 Fe4.77O12, showed the optimum electromagnetic properties： εr=14.2, tanδe=1.5×10–4, Hc=36 A/m, 4πMS=192 mT, Br/Bs=0.84, ？H=6.8 KA/m.

关键词： Mn-substitution YIG microstructure electromagnetic properties rare earths

Dynamic Analysis of A Pontoon-Separated Floating Bridge Subjected to A Moving Load

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China Ocean Engineering 2006年第3期20卷 419-430页

作者：王琮付世晓李宁崔维成林铸明 School of Naval Architecture Ocean and Civil Engineering Shanghai Jiao Tong University Shanghai 200030 China Centre for Ships and Ocean Structures Norwegian University of Science and Technology Trondheim N-7491 Norway Engineering Institute of Engineering Crops PLA University of Science and Technology Nanjing 210007 China China Ship Scientific Research Center Wuxi 214082 China The First Engineers Scientific Research Institute of the General Armament Department Wuxi 214035 China

For the design and operation of a floating bridge, the understanding of its dynamic behavior under a moving load is of great importance. The purpose of this paper is to investigate the dynamic performances of a new type floating bridge, the pontoon-separated floating bridge, under the effect of a moving load. In the paper, a brief summary of the dynamic analysis of the floating bridge is first introduced. The motion equations for a pontoon-separated floating bridge, considering the nonlinear properties of connectors and vehicles＇ inertia effects, are proposed. The super-element method is applied to reduce the numerical analysis scale to solve the reduced equations. Based on the static analysis, the dynamic features of the new type floating bridge subjected to a moving load are investigated. It is found that the dynamie behavior of the pontoon-separated floating bridge is superior to that of the ribbon bridge by taking the nonlinearity of eonneetors into account.

关键词： pontoon-separated floating bridge moving load dynamic FEM nonlinear

Studies on Stochastic Parametric Roll of Ship with Stochastic Averaging Method

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China Ocean Engineering 2020年第2期34卷 289-298页

作者： WANG Li-yuan TANG You-gang LI Yan ZHANG Jing-chen LIU Li-qin School of Civil Engineering Tianjin UniversityTianjin 300072China State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300072China

The paper studies the parametric stochastic roll motion in the random *** differential equation of the ship parametric roll under random wave is established with considering the nonlinear damping and ship *** sea surface is treated as a narrow-band stochastic process,and the stochastic parametric excitation is studied based on the effective wave *** nonlinear restored arm function obtained from the numerical simulation is expressed as the approximate analytic *** using the stochastic averaging method,the differential equation of motion is transformed into Ito’s stochastic differential *** steady-state probability density function of roll motion is obtained,and the results are validated with the numerical simulation and model test.

关键词： parametric roll random wave stochastic averaging method probability density function

Highly efficient Nd:YAG/LBO laser at 473 nm under direct 885-nm diode laser pumping

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Chinese Optics Letters 2010年第2期8卷 187-189页

作者：吕彦飞夏菁王君光张安锋张喜和包琳全慧尹晓东 School of Science Changchun University of Science and Technology Xi'an Institute of Applied Optics Jilin Junkun Optoelectronics Co.Ltd.

In diode pumped Nd：YAG lasers, the quantum defect is the most important parameter determining the thermal load of the laser crystal, which can be dramatically reduced by pumping directly into the upper laser level. A compact folded three-mirror cavity with a length of 105 mm is optimized to obtain a highly efficient 473-nm laser. When the absorbed pump power （with 15.8-W incident pump power） at 885 nm into Nd：YAG is 10 W, a continuous-wave 473-nm blue laser as high as 2.34 W is achieved by LBO intra-cavity frequency doubled. The optical-to-optical conversion efficiency is 14.8%. To the best of our knowledge, this is the highest efficiency at 473 nm bv an intra-cavitv doubled freauencv Nd：YAG laser.

关键词： Conversion efficiency Laser pulses Mirrors Neodymium Pumping (laser) Pumps Thermoanalysis

6.2-W deep blue light generation by intracavity frequency-doubled Nd:GdVO_4 using BiBO

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Chinese Optics Letters 2007年第7期5卷 407-408页

作者：吕彦飞张喜和姚治海张凤东 Department of Physics Changchun University of Sciences and technology Changchun 130022

Efficient continuous-wave （CW） intracavity frequency doubling of a diode-end-pumped Nd：GdVO4 laser operating on ^4F3/2 - ^4I9/2 transitions at 912 nm has been demonstrated. A symmetrical cavity with two laser rods is designed, which divides the pump power between the two laser rods, allowing for greater power scalability. An 18-mm-long BiBO crystal, cut for critical type I phase matching, is used for the intracavity frequency-doubled laser. A maximum output power of 6.2 W in the blue spectral range at 456 nm has been achieved with the pump power of 36 W. The beam quality M2 value is 2.5 in both horizontal and vertical directions. The ellipticity of the deep blue laser is 0.98, and the power stability is better than 3.2% at the maximum output power.

关键词： Beam quality Continuous wave lasers Electron transitions Phase matching Pumping (laser) Semiconductor lasers

All solid-state sum-frequency generation of 1.12-W continuous-wave laser at 588 nm

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Chinese Optics Letters 2007年第6期5卷 353-354页

作者：吕彦飞张喜和姚治海 Department of Physics Changchun University of Sciences and Technology

A new resonator design for doubly resonant continuous-wave （CW） intracavity sum-frequency mixing （SFM） is reported. 1.12 W of coherent radiation at 588 nm is generated by mixing 1062-nm Nd：GdVO4 laser and 1319-nm... 详细信息

关键词： Conversion efficiency Resonators

Serrated flow behavior of GH536 superalloy under different loading rates at room temperature

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Rare Metals 2024年第5期43卷 2317-2323页

作者： Wen-Xiang Gao Dong Ma Li-Li Zhao Fan Ye Ling Shao Su-Jun Wu School of Materials Science and technology Beihang UniversityBeijing100091China

Serrated flow phenomenon has been widely observed among different metals due to the potential influence on their *** tensile tests of nickel-based superalloy GH536 were carried out at loading rates of 0.06,0.60,3.60,and 36.00 mm·min^(-1)at room temperature,*** tensile stress-strain curves demonstrate repetitive and discontinuous yielding behavior,namely serrated *** is observed that the stress-strain curves were dominated by type B serration,and original annealing twin boundaries(TBs)were distorted to various degrees under comparatively different lower tensile *** contrast,the TBs almost disappear,and the type B serrations become smoother and regular under the higher loading *** phenomenon can be attributed to the interactions between TBs and dislocations during tensile *** effects of the mobile and immobile dislocations illustrate the unsteady amplitude of serrations observed in stress-strain *** electron microscope images of tested pieces reveal the interaction of dislocation and TB,with dislocation tangling around the TBs.

关键词： Nickel-based superalloy Serrations Twin boundaries Deformation mechanism