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Investigation of the Heterogeneous Nucleation on Fractal Surfaces

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Journal of Materials Science & Technology 2012年第12期28卷 1169-1174页

作者： Meng Wang Ying zhang Haoyong zheng xin Lin Weidong Huang State Key Laboratory of Solidification Processing Northwestern Polytechnical University Xi'an 710072 China

Classical theory of heterogeneous nucleation has been developed with an implied hypothesis of smooth substrate surfaces; however, morphologies of any real substrate surfaces are generally complicated and demonstrate fractal characteristics. In this paper, the wettability between the embryo and the fractal substrate surface was discussed, and heterogeneous nucleation behaviors were theoretically analyzed. The result shows that the roughness factor of a fractal surface varies with the scale of the embryo. As a result, the fractal character of the substrate surface has important effects on heterogeneous nucleation behaviors. It has been shown that the energy barrier for heterogeneous nucleation of a non-wetting phase on a fractal rough surface increases with increasing fractal dimensions, and both the critical nucleus radius and the nucleation energy barrier decrease with increasing fractal dimensions for heterogeneous nucleation of a wetting phase on the fractal rough surface. For a non-wetting system, the critical nucleus radius shows a slight shift with changes of the intrinsic wetting angle, but for a wetting system, the critical nucleus radius shows an obvious change with decreasing intrinsic wetting angle, thus imposes a stronger effect on the heterogeneous nucleation behaviors.

关键词： Solidification Nucleation Supersaturated solutions Substrate Surface structure

Effects of Enhanced UV-B Radiation on the Activity and Expression of Alternative Oxidase in Red Kidney Bean Leaves

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Journal of Integrative Plant Biology 2007年第9期49卷 1320-1326页

作者： Ming-Guang Zhao Ying-Gao Liu Li-xin zhang Lin zheng Yu-Rong Bi Key Laboratory of Add and Grassland Ecology Ministry of Education School of Life Sciences Lanzhou University Lanzhou 730000 China

An increase in ultraviolet （UV） B radiation on the earth＇s surface is a feature of current global climate changes. It has been reported that alternative oxidase （AOX） may have a protective role against oxidative stress induced by environmental stresses, such as UV-B. To better understand the characteristic tolerance of plants to UV-B radiation, the effects of enhanced UV-B radiation on the activity and expression of AOX in red kidney bean （Phaseolus vulgaris） leaves were investigated in the present study. The results show that the total respiration rate and AOX activity in red kidney bean leaves increased significantly during treatment with enhanced UV-B. However, cytochrome oxidase （COX） activity did not change significantly. The H2O2 content was also markedly increased and reached a maximum of 4.45 mmol·L^-1·g^-1 DW （dry weight） at 24 h of UV-B treatment, before dropping rapidly. Both alternative pathway content and alternative pathway activity were increased in the presence of exogenous H2O2. Immunoblotting analysis with anti-AOX monoclonal antibody revealed that expression of the AOX protein increased in red kidney bean leaves under enhanced UV-B radiation, reaching a peak at 72 h. In addition, AOX expression in red kidney bean leaves was induced by exogenous H2O2. These data indicate that the increase in AOX activity in red kidney bean leaves under enhanced UV-B radiation was mainly due to H2O2-induced AOX expression.

关键词： alternative oxidase red kidney bean respiration UV-B radiation

Study on Multiplexing Ability of Identical Fiber Bragg Gratings in a Single Fiber

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Chinese Journal of Aeronautics 2011年第5期24卷 607-612页

作者： LIU Jiansheng zhang Jing LI xin zheng zheng School of Electronics and lnformation Engineering Beihang University Beijing 100191 China

The multiplexing ability of a novel multiplexing fiber Bragg grating （FBG） method based on Optical Time Domain Reflecto meter （OTDR） and Time Division Multiplexing TDM technologies has been theoretically analyzed and studied. This method permits the interrogation of hundreds of identical FBGs with low reflectivity in a single fiber, making the FBG sensors more applicable in the aerospace health monitoring engineering. The analysis shows that the multiplexing ability can be greatly improved if the FBG reflectivity is sufficiently low. And hence, an inexpensive large-scale distributed sensing system based on this method can be realized, When evaluating the multiplexing ability of this system, we propose for the first time that the interference effect of multi-reflections among FBGs should be taken into consideration.

关键词： Bragg gratings multiplexing low reflectivity multi-reflection interference effect

Raman scattering in In/InOx core-shell structured nanoparticles

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Chinese Physics B 2014年第8期23卷 117-120页

作者： Wang Meng Tian Ye zhang Jian-Ming Guo Chuan-Fei zhang xin-zheng Liu Qian The MOE Key Laboratory of Weak-Light Nonlinear Photonics TEDA Applied Physics School and School of Physics Nankai University Tianjin 300457 China National Center for Nanoscience and Technology Belting 100190 China University of the Chinese Academy of Sciences Beijing 100190 China Department of Physics and TcSUH University of Houston Houston TX 77204 USA

The properties of Raman phonons are very important due to the fact that they can availably reflect some important physical information. An abnormal Raman peak is observed at about 558 cm-1 in In film composed of In/InOx core-shell structured nanoparticles, and the phonon mode stays very stable when the temperature changes. Our results indicate that this Raman scattering is attributed to the existence of incomplete indium oxide in the oxide shell.

关键词： Raman scattering core-shell structure indium nanoparticles

Measurement of Photorefractive Two-Wave Coupling Exponential Gain Coefficient of LiNbO_(3) : Fe Crystal

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Chinese Physics Letters 1998年第5期15卷 348-350页

作者： SUN Qian LI Yu-dong XU Jing-jun LIU Si-min zhang Guang-yin zhang xin-zheng zhang Guo-quan Department of Physics Nankai UniversityTianjin 300071

For a photorefractive crystal,the exponential gain coefficient of two-wave coupling,Г,is a *** this paper,the constantГof a LiNbO_(3):Fe crystal is measured by using Gaussian beams and quasi-uniform *** difference b... 详细信息

关键词： crystal attributed exponential

Stationary Photorefractive Self-Pump Phase-Conjugation with Stimulated Backward Scattering in LiNbO_(3):Fe Crystals

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Chinese Physics Letters 1999年第1期16卷 29-31页

作者： XU Jing-jun zhang xin-zheng SUN Qian zhang Guo-quan N.Kamber LIU Si-min zhang Guang-yin Photonics Research Center College of Physical ScienceNankai UniversityTianjin 300071

Stationary photorefractive self-pumped phase-conjugation with one four-wave-mixing interaction region,stimulated by the photorefractive amplified backward scattering,is obtained in LiNbO3:Fe crystals,in which the strong backward scattered light is gotten by putting a scattering particle on the backface of the *** though its reflectivities are not high(its temporal and stationary reflectivities are 10%and 3%,respectively),due to the low electrooptic coefficients of LiNbO3:Fe crystals,our experimental results prove that this mechanism is effective and simple comparing with the“cat”self-pumped phase-conjugator.

关键词： scattering pumped Photorefractive

Forward Phase Conjugation Wave due to Multi-wave Coupling and Grating Share in Lithium Niobate Crystal

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Chinese Physics Letters 2001年第12期18卷 1601-1603页

作者： QIAO Hai-Jun XU Jing-Jun zhang xin-zheng LI Fei-Fei SUN Qian WU Qiang zhang Guang-Yin Photonics Research Center Department of PhysicsNankai UniversityTianjin 300071TEDA CollegeNankai UniversityTianjin 300457

The steady intensity of a forward phase conjugate wave (FPCW) is successfully observed along the c-axis in the highly magnesium-doped lithium niobate crystal. We put forward a detailed physical picture for our experiment phenomena. The FPCW is generated from the phase-mismatch in a three-wave coupling process, and tends to be stable accompanied with the building of photorefractive gratings and four-wave coupling processes. Our experimental result is also discussed and analysed by means of the wave coupling theory, and the theoretical expression is provided for the experiment.

关键词： wave Crystal coupling

Optically Controlled Coherent Backscattering from a Water Suspension of Positive Uniaxial Microcrystals

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Chinese Physics Letters 2012年第1期29卷 130-132页

作者： SHI Fan LI Wei WANG Pi-Dong LI Jun WU Qiang WANG Zhen-Hua zhang xin-zheng MOE Key Laboratory of Weak-Light Nonlinear Photonics TEDA Applied Physics School and School of PhysicsNankai UniversityTianjin 300457

Coherent backscattering of light from a water suspension of zirconium silicate microcrystals is *** controlled weak localization of photons is realized,which is due to the reorientation behaviors of positive uniaxial microcrystals induced by a linearly polarized pump *** zirconium silicate particles are positive uniaxial microcrystals,their reorientation behaviors are contrary to negative *** work widely extends the materials used in the light-controllable weak localization of photons.

关键词： zirconium silicate pump

Pump Intensity Dependence of Two-Beam Coupling in Doped Lithium Niobate Crystals

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Chinese Physics Letters 2000年第6期17卷 431-432页

作者： Nouel Y.Kamber XU Jing-Jun Sonia M.Mikha SONG Feng zhang Guo-Quan zhang xin-zheng LIU Si-Min zhang Guang-Yin Photonics Research Center College of Physics ScienceNankai UniversityTianjin 300071

We demonstrated experimentally the dependence of two-beam coupling on the incident pump intensity in our samples of doped LiNbO_(3)*** results show that there is an optimum pump intensity for the signal beam amplification,which can be easily controlled by doping the LiNbO_(3)crystal with suitable concentrations of Fe and damage-resistant dopants such as Mg,In,and Zn.

关键词： pump dopant beam