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Photoluminescence Characterization of Boron-doped Si Layers Grown by Molecular Beam Epitaxy

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Semiconductor Photonics and Technology 2005年第4期11卷 225-227页

作者： LI Cheng LAI Hong-kai CHEN Song-yan Research Center for Semieond. Photon. Dept. of Phys. Xiamen University Xiamen 361005 CHN

Photoluminescence spectra were used to characterize the boron-doped Si layers grown by molecular beam epitaxy using HBO2 as the doping source. The influence of boron doping concentration on the dislocation-related photoluminescence spectra of molecular beam epitaxy Si layers annealed at 900℃ was studied with different doping concentrations and growth temperature. The broad photoluminescence band（from 0.75eV to 0.90eV） including D1 and D2 bands was associated with high boron doping concentration in the samples, while D3 and D4 bands might be related to oxygen precipitates.

关键词： Photoluminescence Boron-doped silicon layer Dislocations

Effects of Preparation on Luminescent Characterization of Porous Silicon

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Semiconductor Photonics and Technology 2002年第4期8卷 238-241,252页

作者： SHI Xiang hua, LIU Xiao bing (dept. of phys. and inform. Tech., Changsha Univ. of Electr. Power, Changsha 410077, CHN) dept. of phys. and inform. Tech. Changsha Univ. of Electr. Power Changsha 410077

Porous silicon samples are prepared by pulse electrochemical etching and DC electrochemical etching. The effects of different preparation methods on luminescent characterization of porous silicon are investigated. Compared with DC electrochemical etching, pulse electrochemical etching produces the porous silicon characterized by a more even surface, a stronger luminescence and a PL blue shift to a certain degree.

关键词： Pulse etching Blue shift Preparation

Photoluminescence Spectra of Post-heat-treated Porous Silicon

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Semiconductor Photonics and Technology 2002年第4期8卷 234-237页

作者： LIU Xiao bing, SHI Xiang hua (dept. of phys. and Inform. Tech ., Changsha Univ. of Electr. Power, Changsha 410077, CHN) dept. of phys. and Inform. Tech. Changsha Univ. of Electr. Power Changsha 410077

Porous silicon prepared by pulse electro-etching is heat-treatedin O_2 atmosphere with an enhancement of its PI. peak and animprovement of its PL stability. The PL peak of a sample poroussilicon treated in O_2 atmosphere at 1000 ℃ presents itself a three--peak structure and, compared with an un-- heat--treated sample,there exists blue shift of ～ 40 nm.

关键词： Heat treatment Blue shift Stability

Influence of Processing Parameters on the Magnetic Properties of Mn-Zn Ferrites

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Journal of Minerals and Materials Characterization and Engineering 2011年第5期10卷 397-407页

作者： S. A. El-Badry ME Lab. Phys. Dept. Faculty of Science Al-Azhar Univ. Nasr City Cairo Egypt.

Pure MnO2, ZnO and Fe2O3 were used to prepare a Mn-Zn Ferrite sample of the nominal composition Mn0.64Zn0.29Fe2.07O4. These oxides were mixed firstly for 1hr, and then were milled for 20 and for 40 hrs. The as-mixed and the milled powders were examined by XRD and ME spectroscopy. The investigated samples were further mixed with PVA, granulated, cold pressed and sintered at different temperatures (1000, 1300 and 1400 oC) for 2 hrs and were then reinvestigated again. The magnetic properties of all samples before and after sintering were characterized using VSM at a field of 15 k Oe. When the powder oxides were milled for 20 hrs, detectable diffusion reaction was observed where the centers of all XRD peaks (due to Fe2O3 and MnO2) shifted to higher 2? angles, suggesting that Zn2+ cations had diffused through Fe3+ and/or Mn4+ lattices. The observed increase in the width of the XRD peaks can be attributed to the refinement of the powders by milling. Milling of the powder for 40 hrs resulted in the formation of spinel phase of (Zn, Fe), but MnO2 was disappeared probably due to the formation of amorphous structure. Sintering at 1000, 1300, and 1400 oC resulted in the formation of different spinel (Mn-Zn) ferrites. The ME measurements followed the gradual formation the manganese zinc ferrite until complete formation which observed in the sample that milled for 40 hrs followed by sintering at 1300 oC for two hrs. However, it can be concluded that, the processing conditions of such sample represent are the best conditions for obtaining a soft manganese zinc ferrite (single phase).

关键词： Mn-Zn ferrite Ferrites Soft magnets XRD ME spectroscopy and Magnetic properties.

From Droplets and Particles to Hierarchical Spatial Organization： Nanotechnology Challenges for Microfluidics

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Journal of phys.cal Science and Application 2011年第3期1卷 125-134页

作者： J. Michael Kohler P. Mike Gvnther Anette Funfak Jialan Cao Andrea Knauer Shuning Li Steffen Schneider G. Alexander Gross Techn. Univ. llmenau Institute of Micro- and Nanotechnologies/Institute for Physics Dept. Phys. Chem. and MicroreactionTechnology llmenau Germany

The compartimentation of fluids in the microliter, nanoliter and picoliter range leads recently to many applications of microfluidics in material development, diagnostics and biological screenings. Droplet-based microfluidics allows the improvement of nanoparticle homogeneity and the tuning of particle properties. It supports combinatorial synthesis of inorganic as well as organic substances and can be applied for the cultivation and screening of bacteria, eucaryotic cells and fish embryos. The well-ordered handling and the addressing of microfluid segments improves the information transfer between chemical, biological and electronic systems. Despite this remarkable technical progress, there is a particular importance of microfluidics for future nanotechnological solutions. The hierarchical spatial organization of liquids, particles and gels in microfluidics represents a fundamental biomimetic principle which overcomes the limits of planar technology and opens the gate for realizing complex structured threedimensional nanoarchitectures. Recent applications of microstructured fluids in chemistry and biology and concepts for future developments will be discussed.

关键词： Nanotechnology microfluidics nanoparticles segmented flow concentration spaces screening nested phases hierarchical organization droplet-based systems.

SABRE雷达及其观测的Pc5地磁脉动Ⅰ.统计分析结果

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空间科学学报 1992年第3期12卷 235-240页

作者：田茂 T.K.Yeoman M.Lester T.B.Jones 武汉大学空间物理系 430072 dept. of phys. & Astronomy Univ. of Leicester U.K.

本文简要介绍了相干散射雷达SABRE及其观测Pc5地磁脉动的工作原理。1985—1989年观测数据的统计分析结果表明,相位向极传播脉动事件的出现率峰值在当地时间午夜附近,而向赤道传播事件的出现率峰值则在18:00LT左右。文中给出了上述两类... 详细信息

本文简要介绍了相干散射雷达SABRE及其观测Pc5地磁脉动的工作原理。1985—1989年观测数据的统计分析结果表明,相位向极传播脉动事件的出现率峰值在当地时间午夜附近,而向赤道传播事件的出现率峰值则在18:00LT左右。文中给出了上述两类脉动事件出现率的日变化,与地磁活动的相关,与背景电离层等离子体对流特性的关系等统计分析结果。

关键词：相干散射雷达地磁脉动观测

EXACT SOLUTIONS OF SOME FIFTH-ORDER NONLINEAR EQUATIONS

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Applied Mathematics(A Journal of Chinese Universities) 2000年第1期15卷 28-32页

作者： Liu Xiqiang\ Bai ChenglinInstitute of Appl.phys. and Com putational Mathem atics,PO Box 2101,Beijing 100088 dept.of Math.,Liaocheng Teachers Univ.,Liaocheng 252059.dept. of Com m unication Engineering,Liaocheng Teachers Univ.,Liao cheng 252059. Institute of Appl. phys. and Computational Mathematics Beijing dept. of Math. Liaocheng Teachers Univ. Liaocheng dept. of Communication Engineering Liaocheng Teachers Univ. Liao cheng

To solve the nonlinear partial differential equations is changed into solving some algebraic equations by using the function U to be expressed as linear independent functions. The new soliton and periodic solution... 详细信息

关键词： Fifth-ordernonlinear partialdifferentialequations linear independentfunctions soliton so- lutions.

Conductive Mechanism of Organic Conductor

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Semiconductor Photonics and Technology 2002年第3期8卷 140-144页

作者： ZHOU Yu fang 1,2 , LIU Zhi 2 (1. dept. of phys., Shandong University, Jinan 250100, CHN 2. State Key Lab. of Cryst. Mater., Shandong University, Jiana 250100, CHN) dept. of phys. Shandong University Jinan 250100 Shandong University State Key Lab. of Cryst. Mater. Jinan 250100

Organic conductor is a kind of organic compound which has special electronic and magnetic properties. The research of the organic compounds has received considerable attention because of their potential applications in many areas. The molecular conductive units are theoretically investigated as well as their energy gap and charge distribution. The relationship of conductivity and micro mechanism is discussed.

关键词： Organic conductor Energy band Conductivity

Audio watermarking based on psychoacoustic model and critical band wavelet transform

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Chinese Journal of Acoustics 2007年第1期26卷 63-72页

作者： TAO Zhi ZHAO Heming GU Jihua WU Di School of phys. Sci. and Tech. Suzhou Univ. Suzhou 215006 dept. of Electron School of InformationSuzhou Univ. Suzhou 215006

Watermark embedding algorithm based on critical band wavelet transform of digital audio signal is proposed in this paper. The masking threshold for each audio signal segment was calculated on the basic of psychoacoustic model. According to the similarity between critical band of human auditory system and critical band wavelet transform, a watermark was embedded into the low-band and mid-band coefficients of digital wavelet. The embedding strength was adaptively controlled by the masking threshold. The experiment results show that the embedded watermark signal is inaudible, and the watermarked audio signal has good robustness against many attacks such as compression, noise, re-sampling, low-pass filtering.

关键词： wavelet transform audio signal human auditory system psychoacoustic model