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Design and performance of superconducting filter with a linear phase for CDMA2000 communication system

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Science china(information Sciences) 2010年第9期53卷 1903-1907页

作者： JI LaiYun1*,MA Jie1,2,SUN Jun1,WANG Lang1,LI YanQi1,XU KaiWei1,XIAO GuoDong1 & REN JianCheng1 1tianjin Hi-Tech Superconducting Electronic Technologies Co.Ltd,tianjin 300384,china 2department of information engineering,hebei university of technology,tianjin 300130,china 1. tianjin Hi-Tech Superconducting Electronic Technologies Co. Ltd Tianjin 300384 China2. Department of Information Engineering Hebei University of Technology Tianjin 300130 China

A high temperature superconducting(HTS) filter with a linear phase is designed for CDMA2000 communication *** principle and equivalent model of the filter have been *** theoretical result,coupling matrix,and the simulated result with Sonnet software have also been *** desired filter with 12-pole and 2 cross couplings has a center frequency of 830 *** measurement results show that the response of practical filters is in good agreement with that of simulated results and theoretical analysis,the group delay variation is less than ±10 ns over 60% of the filter bandwidth,and the skit slope of the filter is about 37 dB/MHz.

关键词： HTS filter linear phase group delay CDMA2000 communication system

Three-Dimensional and Cross-sectional Characteristics of Normal Grain Growth Based on Monte Carlo Simulation

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International Journal of Minerals,Metallurgy and Materials 1998年第3期12卷 129-133,139页

作者： Xiaoyan Song Guoquan Liu(Material Science and engineering School, university of Science and technology Beijing, Beijing 100083, china)(department of Materials Science and engineering, hebei university of technology, tianjin 300130, china) Material Science and engineering School University of Science and Technology Beijing Beijing 100083 China departments of Materials Science and engineering Hebei University of Technology Tianjin 300130 China

An appropriate Monte Carlo method was developed to simulate the three-dimensional normal grain growth more completely. Comparative investigation on the three-dimensional and the cross-sectional characteristics of normal grain growth was done. It was found that the time exponent of grain growth determined from cross-section exhibits the same rule of increasing slowly with time and approaching the theoretical value n = 0.5 of steadygrain growth as the three-dimensional (3-D) system. From change of the number of grains per unit area with timemeasured in cross-section, the state of 3-D normal grain growth may be predicted. The gtain size distribution incross-section is different from that in 3-D system and can not express the evolution characteristic of the 3-D distribution. Furthermore, there exists statistical connection between the topological parameters in cross-section and thosein three-dimensions.

关键词： Monte Carlo simulation normal grain growth three-dimension cross-section characteristics

Synthesis of nanostructural ZnO using hydrothermal method for dye-sensitized solar cells

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Science china(Technological Sciences) 2010年第4期53卷 1146-1149页

作者： WANG ChunXiao1,2,ZHANG XiaoDan1,WANG DongFeng1,YANG ZhenHua1,2,JI WeiWei1,ZHANG CunShan2 & ZHAO Ying1 1 Institute of Photo-electronic Thin Film Devices and technology of Nankai university,Key Laboratory of Photo-electronic information Science and technology(Nankai university),Ministry of Education,tianjin 300071,china 2 College of information engineering,hebei university of technology,tianjin 300130,china 1. Key Laboratory of Photo-electronic information Science and technology (Nankai university) Ministry of Education Institute of Photo-electronic Thin Film Devices and Technology of Nankai University Tianjin 300071 China2. College of Information Engineering Hebei University of Technology Tianjin 300130 China

ZnO nanocrystals with different morphologies were successful synthesized by a simple hydrothermal method combined with and without hexadecyl trimethyl ammonium bromide(CTAB).The phases and morphologies of the products were measured using X-ray diffraction(XRD),scanning electron microscopy(SEM),and transmission electron microscopy(TEM),*** results indicated that the ZnO nanocrystals with different morphologies were of hexagonal wurtzite *** nanorods were obtained without using CTAB,and then the morphology of ZnO changed to ZnO nanoflower and the density of nanoflower became denser with the increase of CTAB *** nanoflower and ZnO nanorod as photoanode were applied to dye-sensitized solar cells(DSSC),*** nanoflower shows a higher dye loading,so DSSC with the use of the ZnO nanoflower possesses a higher conversion efficiency than ZnO nanorod.

关键词： DSSC ZnO

Large Eddy Simulation of New Vortex Generator Enhancing Heat Exchange of Solar Energy

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湖南大学学报（自然科学版） 2009年第S1期36卷 186-192页

作者： WEN Juan,YANG Li,QI Cheng-ying(department of Thermal Power engineering,hebei university of technology,tianjin 300401,china) department of Thermal Power engineering Hebei University of Technology Tianjin 300401 China

This paper put forward a new-type vortex generator enhancing heat exchange of solar air-drier and air-heater on the gas side,and investigated the mechanism of heat transfer enhancement and drag reduction by the influence of vortex generators on the coherent structure of turbulent boundary *** flow and heat transfer characteristics of rectangle channel with bevel-cut half-elliptical column vortex generators were obtained using large eddy simulation(LES)and the hydromechanics software *** instantaneous properties of velocity,temperature and pressure in channel were *** coherent structure of turbulent boundary layer flow was showed,and the characteristic of vortex induced by inclined-cut semi-ellipse vortex generator and its influence on turbulent coherent structure were *** the effect mechanism of turbulent coherent structure on flow field,pressure field and temperature field was *** on the results,the heat transfer coefficient and drag reduction of the new vortex generator with different pitch angles were ***,the coherent effects of the increased wall heat transfer and the decreased skin friction do not satisfy the Reynolds *** turbulent coherent structure can be controlled through the geometry of the vortex generator,so the heat transfer and drag reduction can also be *** we can seek suitable form of vortex generator and structure parameters,in order to achieve the enhanced heat transfer and flow of drag reduction in the solar air-heater and solar air-drier.

关键词： large eddy simulation vortex generator bevel-cut half-elliptical column coherent structure heat transfer enhancement

High Temperature Deformation of Al_2O_3/Cu Composites

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Journal of Materials Science & technology 2001年第3期17卷 325-328页

作者： Jianjun WU. Yun ZHANG, Yanfei JIANG and Meiyun XUE department of Material Science and engineering, hebei university of technology, tianjin 300130, china Tingquan LEI School of Materials Science and engineering, Harbin Institute of technology, Uarbin 15000 hebei Univ Technol Dept Mat Sci & Engn Tianjin 300130 Peoples R China Harbin Inst Technol Sch Mat Sci & Engn Harbin 150006 Peoples R China

This work concerns with the high temperature deformation of internally oxidized Al2O3/Cu composites. The investigation revealed that dispersive alumina can obstruct dislocation sliding and define the subgrain size thereby improve significantly the strength of the materials at high temperature. The sliding of dislocations is a main deformation mechanism in the given temperature range. The sliding of grain boundary and diffusive creep play important roles at high temperature and low strain rate. The dispersoids can raise the recrystallization temperature to higher than 1223 K. Dynamic recovery is a main softening way under the experimental conditions. Higher deformation rate and lower deformation temperature imply a higher flow stress.

关键词： High Temperature Deformation of Al2O3/Cu Composites Cu Al

Electroabsorption spectrum of substituted polyphenylacetylenes

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Chinese Science Bulletin 1998年第14期43卷 1215-1219页

作者： CHENG Xiaoman department of Optoelectronic information engineering, tianjin Institute of technology, tianjin 300191, china department of Optoelectronic information engineering Tianjin Institute of Technology Tianjin China

Electroabsorption (EA) measurements on thin films of poly[ o (trimethylsilyl) phenylacetylene] and poly[ o (trimethylsilylmethyl) phenylacetylene] have been performed. The spectral change induced by an exernal electric field (EA spectra) has been observed, which shows the similar shape of the second derivative of the optical absorption spectra. The change in the absorption Δ α is obtained from the EA spectrum, and Δ n is calculated through Kramers_Krong transformation. The optical properties of substituted polyphenylacetylenes (PPAs) were discussed.

关键词： substituted polyphenylacetylenes electroabsorption spectrum optical nonlinearities

Two-photon spectroscopic behaviors and photodynamic effect on the BEL-7402 cancer cells of the new chlorophyll photosensitizer

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Science china Chemistry 2008年第6期51卷 529-538页

作者： ZHAO PeiDe1,2,CHEN Ping1,TANG GuoQing1,LIU JinWei2,LIN Lie1,GUO Peng1,YU Qing2, YAO JianZhong3,MA DongMing4,ZHANG GuiLan1 & CHEN WenJu1 1 Key Laboratory of Optoelectronic information Science and technology,Ministry of Education,Institute of Modern Optics,Nankai university,tianjin 300071,china 2 department of Physics,hebei university of technology,tianjin 300130,china 3 College of Pharmacy,Second Military Medical university,Shanghai 200433,china 4 tianjin College of the Traditional Chinese Medicine,tianjin 300193,china 1. Key Laboratory of Optoelectronic information Science and technology Ministry of Education Institute of Modern Optics Nankai University Tianjin 300071 China 2. department of Physics Hebei University of Technology Tianjin 300130 China 3. College of Pharmacy Second Military Medical University Shanghai 200433 China 4. tianjin College of the Traditional Chinese Medicine Tianjin 300193 China

The spectroscopic properties of a new chlorophyll derivate photosensitizer (CDP) are studied under the excitation wavelengths at 800 and 400 nm using femtosecond pulses from a Ti: sapphire laser. The damaging effect of CDP on the BEL-7402 cancer cells is also investigated upon two-photon illumination at 800 nm. The normalized fluorescence spectra of CDP in tetrahydrofuran (THF) show that two-photon and one-photon spectra have the same distributions and the same emission bands (675 nm). The lifetimes of two- and one-photon induced fluorescence of this molecule are of the order of 5.0 ns. By comparing the data it is shown that there is some difference between the two lifetimes, but the difference is less than one nanosecond. The two-photon absorption cross section of the molecule is also measured at 800 nm and estimated as about σ'_2 ≈ 31.5x10^(-50)cm^4·s·photon^(-1). The results of two-photon photodynamic therapy (TPPDT) tests show that CDP can kill all of the tested cancer cells according to the usual Eosine assessment. Our results indicate that the two-photon-induced photophysical, photochemical and photosensitizing processes of CDP may be basically similar to those of one-photon excitation. These behaviors of the sample suggest that one may find other possible methods to estimate some photosensitizers' effects in details such as their distribution in cells and the reactive targets of the sub-cellular parts of some tumor cells via two-photon excitation techniques.

关键词： photosensitizer chlorophyll derivate two-photon fluorescence two-photon absorption cross-section TPPDT BEL-7402 cell

Bell violation for the thermal states of an XXZ spin chain with Dzialoshiski-Moriya interaction

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Science china(Physics,Mechanics & Astronomy) 2010年第11期53卷 2074-2079页

作者： MA XiaoSan 1 & WANG AnMin 2 1 School of Electric engineering and information,Anhui university of technology,Maanshan 243002,china 2 department of Modern Physics,university of Science and technology of china,Hefei 230026,china 1. School of Electric engineering and information Anhui University of Technology Maanshan 243002 China2. Department of Modern Physics University of Science and Technology of China Hefei 230026 China

The effect of Dzialoshiski-Moriya (DM) interaction on the violation of Bell inequality for thermal states of interacting qubits via a two-qubit XXZ spin chain is *** results imply that the DM interaction and anisotropy taking a large positive value can enhance the Bell violation and improve the threshold temperatures of *** the comparison between the Bell violation and thermal entanglement,we find that the threshold temperatures of thermal entanglement are higher than those of the Bell *** implies that some states are entangled but the Bell inequality is not violated.

关键词： Bell violation threshold temperatures DM interaction

The reliability of the improved e^N method for the transition prediction of boundary layers on a flat plate

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Science china(Physics,Mechanics & Astronomy) 2012年第5期55卷 837-843页

作者： SU CaiHong1,2 1 department of Mechanics,tianjin university,tianjin 300072,china 2 tianjin Key Laboratory of Modern engineering Mechanics,tianjin 300072,china 1. department of Mechanics Tianjin University Tianjin 300072 China2. Tianjin Key Laboratory of Modern Engineering Mechanics Tianjin 300072 China

The transition criterion in the improved eN method is that transition would occur whenever the velocity amplitude of disturbance reaches 1%-2% of the free stream velocity,while in the conventional eN method,the N factor is an empirical *** this paper the reliability of this key assumption in the improved eN method is checked by results of transition prediction by using the Parabolized Stability Equations(PSE).Transition locations of an incompressible boundary layer and a hypersonic boundary layer at Mach number 6 on a flat plate are predicted by both the improved eN method and the PSE *** from both methods agree fairly well with each other,implying that the transition criterion proposed in the improved eN method is reliable.

关键词： transition prediction boundary layer eN PSE