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Realizing high thermoelectric performance for p-type SiGe in medium temperature region via TaC compositing

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Journal of Materiomics 2023年第5期9卷 984-991页

作者： Zheng Fan JiSheng Liang Jun-Liang Chen Ying Peng Huajun Lai Jian Nong Chengyan Liu Wangyang Ding Lei Miao Guangxi key laboratory for Relativity Astrophysics State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite StructuresSchool of Physical Science and TechnologyGuangxi UniversityNanning530004China Engineering Research Center of Electronic information Materials and Devices Ministry of EducationGuangxi Key Laboratory of Information MaterialGuilin University of Electronic TechnologyGuilin541004China Guangxi key laboratory of Precision Navigation Technology and Application Guilin University of Electronic TechnologyGuilin541004China Guangxi Academy of Sciences Nanning530007China

SiGe is recognised as an excellent thermoelectric material with superior mechanical properties and thermal stability in regions with high *** study explores a novel strategy for coregulating thermoelectric transport parameters to achieve high thermoelectric properties of p-type SiGe in the mid-temperature region by incorporating nano-TaC into SiGe combined ball milling with spark plasma *** optimizing the amount of TaC in the SiGe matrix,the power factors were significantly increased due to the modulation doping effect based on the work function matching of SiGe with ***,the ensemble effect of the nanostructure leads to a significant decrease in thermal ***,a high ZT of 1.06 was accomplished at 873 K,which is 64%higher than that of typical radioisotope thermoelectric *** research offers a novel strategy for expanding and enhancing the thermoelectric properties of SiGe materials in the medium temperature range.

关键词： SiGe Thermoelectric Work function matching Modulation doping effect Phonon scattering

Integrability Aspects and Soliton Solutions for a System Describing Ultrashort Pulse Propagation in an Inhomogeneous Multi-Component Medium

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Communications in Theoretical Physics 2010年第9期54卷 536-544页

作者：郭睿田播吕兴张海强许韬 state key {2. of Software Development Environment Beijing University of Aeronautics and Astronautics School of Science Beijing University of Posts and Telecommunications Department of Mathematics Taiyuan University of Technology key laboratory of {2. Photonics and Optical Communications(BUPT) Ministry of EducationBeijing University of Posts and Telecommunications

For the propagation of the ultrashort pulses in an inhomogeneous multi-component nonlinear medium, a system of coupled equations is analytically studied in this paper. Painleve analysis shows that this system admits the Painleve property under some constraints. By means of the Ablowitz-Kaup-Newell-Segur procedure, the Lax pair of this system is derived, and the Darboux transformation （DT） is constructed with the help of the obtained Lax pair. With symbolic computation, the soliton solutions are obtained by virtue of the DT algorithm. Figures are plotted to illustrate the dynamical features of the soliton solutions. Characteristics of the solitons propagating in an inhomogeneous multi-component nonlinear medium are discussed：（i） Propagation of one soliton and two-peak soliton; （ii） Elastic interactions of the parabolic two solitons; （iii） Overlap two head-on solitons and two head-on two-peak solitons; （v） Two （vi） Decomposition phenomenon of one soliton into two solitons. phenomenon between two solitons; （iv） Collision of different types of interactions of the three solitons; ultrashort-pulse propagation in the inhomogeneous multi-component The results might be useful in the study on the nonlinear media.

关键词： ultrashort pulses Painleve analysis Lax pair Darboux transformation soliton symbolic computation

Compact Arrayed-Waveguide Grating on Silicon-on-Insulator with Integrated Waveguide Turning Mirrors

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Chinese Physics Letters 2005年第12期22卷 3100-3103页

作者：李广波龚昭贾科淼龙文华杨建义江晓清王跃林王明华 Department of information and Electronic Engineering and state {2. laboratory of Modern Optical Instrumentation Zhejiang University Hangzhou 310027 state key Laboratories of Transducer Technology Shanghai Institute of Microsystem and Intbrmation Technology Chinese Academy of Sciences Shanghai 200050 Zhejiang University City College Hangzhou 310015

A compact arrayed-waveguide grating （AWG） on the silicon-on-insulator material is designed and fabricated with employment of waveguide-integrated turning mirrors （WITMs）. By properly setting the incident angle with the value of 45°, the effective area of the WITM AWG is only 1.15 cm×1.15 cm with the arrayed waveguide area of 0.6cm×0.6cm. The crosstalk of the fabricated 1×6 AWG is better than -19 dB. The on-chip insertion loss is about -8.8 dB and the output nonuniformity is less than 0.6 dB. The polarization-dependent central wavelength shift is about 0.048nm and the polarization dependent loss is neglectable.

关键词： LOW-POLARIZATION SENSITIVITY CROSS-SECTION DEMULTIPLEXER COUPLER

Satellite-Based Estimation of Daily Average Net Radiation under Clear-Sky Conditions

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Advances in Atmospheric Sciences 2014年第3期31卷 705-720页

作者： HOU Jiangtao JIA Gensuo ZHAO Tianbao WANG Hesong TANG Bohui key laboratory of Regional Climate-Environment Research for East Asia Institute of Atmospheric Physics Chinese Academy of Sciences University of the Chinese Academy of Sciences state key {2. of Resources and Environment information System Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences

ABSTRACT Daily average net radiation （DANR） is an important variable for estimating evapotranspiration from satellite data at regional scales, and is used for atmospheric and hydrologic modeling, as well as ecosystem management. A scheme is proposed to estimate the DANR over large heterogeneous areas under clear-sky conditions using only remotely sensed data. The method was designed to overcome the dependence of DANR estimates on ground data, and to map spatially consistent and reasonably distributed DANR, by using various land and atmospheric data products retrieved from MODIS （Moderate Resolution Imaging Spectroradiometer） data. An improved sinusoidal model was used to retrieve the diurnal variations of downward shortwave radiation using a single instantaneous value from satellites. The downward shortwave component of DANR was directly obtained from this instantaneous value, and the upward shortwave component was estimated using satellite-derived albedo products. Four observations of air temperature from MOD07_L2.and MYD07_L2.data products were used to derive the downward longwave component of DANR, while the upward longwave component was estimated using the land surface temperature （LST） and the surface emissivity from MOD1 l_L2. Compared to in situ observations at the cropland and grassland sites located in Tongyu, northern China, the root mean square error （RMSE） of DANR estimated for both sites under clear-sky conditions was 37 W m-2.and 40 W m-2. respectively. The errors in estimation of DANR were comparable to those from previous satellite-based methods. Our estimates can be used for studying the surface radiation balance and evapotranspiration.

关键词： daily average net radiation satellite climate model four-component radiation surface radiation balance

Segmentation of High Spatial Resolution Remote Sensing Images of Mountainous Areas Based on the Improved Mean Shift Algorithm

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Journal of Mountain Science 2015年第3期12卷 671-681页

作者： LU Heng LIU Chao LI Nai-wen GUO Jia-wei state key {2. of Hydraulics and Mountain River Engineering Sichuan University College of Hydraulic and Hydroelectric Engineering Sichuan University key laboratory of Geo-special {2. Technology Ministry of Land and ResourcesChengdu University of Technology Faculty of Geosciences and Environmental Engineering Southwest Jiaotong University

Using conventional Mean Shift Algorithm to segment high spatial resolution Remote sensing images of mountainous areas usually leads to an unsatisfactory result, due to its rich texture information. In this paper, we propose an improved Mean Shift Algorithm in consideration of the characteristics of these images. First, images were classified into several homogeneous color regions and texture regions by conducting variance detection on the color space. Next, each homogeneous color region was directly segmented to generate the preliminary results by applying the Mean Shift Algorithm. For each texture region, we conduct a high-dimensional feature space by extracting information such as color, texture and shape comprehensively, and work out a proper bandwidth according to the normalized distribution density. Then the bandwidth variable Mean Shift Algorithm was applied to obtain segmentation results by conducting the pattern classification in feature space. Last, the final results were obtained by merging these regions by means of the constructed cost functions and removing the oversegmented regions from the merged regions. It has been experimentally segmented on the high spatial resolution remote sensing images collected by Quickbird and Unmanned Aerial Vehicle(UAV). We put forward an approach to evaluate the segmentation results by using the segmentation matching index(SMI). This takes into consideration both the area and the spectrum. The experimental results suggest that the improved Mean Shift Algorithm outperforms the conventional one in terms of accuracy of segmentation.

关键词： Mean Shift Image segmentation Regionmerging UAV image Quickbird image

Regional-scale Surface Air Temperature and East Asian Summer Monsoon Changes during the Last Millennium Simulated by the FGOALS-gl Climate System Model

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Advances in Atmospheric Sciences 2014年第4期31卷 765-778页

作者： MAN Wenmin ZHOU Tianjun state key {2. of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences key laboratory of Meteorological Disaster of Ministry of Education Nanjing University of Information Science and Technology Climate Change Research Center Chinese Academy of Sciences

The spatial patterns and regional-scale surface air temperature （SAT） changes during the last millennium,as well as the variability of the East Asian summer monsoon （EASM） were simulated with a low-resolution version of Flexible Global Ocean-Atmosphere-Land-Sea-ice （FGOALS-gl） *** model was driven by both natural and anthropogenic forcing *** features of the simulated past millennial Northern Hemisphere （NH） mean SAT variations,including the Medieval Climate Anomaly （MCA）,the Little Ice Age （LIA） and the 2.th Century Warming （2.CW）,were generally consistent with the *** simulated MCA showed a global cooling pattern with reference to the 1961-90 mean conditions,indicating the 2.CW to be unprecedented over the last millennium in the *** LIA was characterized by pronounced coldness over the continental extratropical NH in both the reconstruction and the *** simulated global mean SAT difference between the MCA and LIA was 0.14°C,with enhanced warming over high-latitude NH continental *** between the simulation and the reconstruction on regional scales were lower than those on hemispheric *** major features agreed well between the simulated and reconstructed SAT variations over the Chinese domain,despite some inconsistency in details among different *** EASM circulation during the MCA was stronger than that during the LIA The corresponding rainfall anomalies exhibited excessive rainfall in the north but deficient rainfall in the *** the zonal and meridional thermal contrast were enhanced during the *** temperature anomaly pattern favored a stronger monsoon circulation.

关键词： last millennium surface air temperature spatial patterns regional-scale variation East Asian summer monsoon

Weak invertibility of linear finite automata over rings——Classification and enumeration

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Chinese Science Bulletin 1996年第3期41卷 190-196页

作者：戴宗铎叶顶锋 state key Lab. of Info. {2. Department of Mathematics Chinese Academy of Sciences Beijing 100039 China

The weak invertibility problem of finite automata (FAs) has received continuous considerations. The weak invertibility theory has applications in cryptography, both conventional cryptosystems and public key cryptosystems. Given a finite commutative ring (?) with identity, it is known, that the weak invertibility of a linear finite automaton(LFA) over (?) depends only on its transfer function matrix. Let H be the set of all possible transfer function matrices which weakly invertible LFAs over (?) can have. Our

关键词： linear finite automaton weak invertibility transfer function matrix.

Role of TiO2.Nanotube on Improvement of Performance of Hybrid Photovoltaic Devices

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Chinese Physics Letters 2009年第1期26卷 272-275页

作者：师全民侯延冰李研冯志慧刘小君 key laboratory of Luminescence and Optical {2. (Ministry of Education) Institute of Optoelectronic Technology Beijing Jiaotong University Beijing 100044

The performance of TiO2.nanotubes in bulk heterojunction of poly （2.methoxy-5-（2.-ethylhexyloxy）-1, 4-phenylenevinylene）（MEH-PPV）/TiO2.nanotubes is investigated. The transport properties are studied by using the time-of-flight technique （TOF）. The carrier mobilities of both holes and electrons are not improved for the MEH-PPV：TiO2.composites compared with the pristine MEH-PPV. However, photoluminescence under the influence of the electric field indicates that the dissociation of excitons in the MEH-PPV：TiO2.composites, which is facilitated by photoinduced charge transfer, only requires a smaller electric field.

关键词： TITANIUM dioxide NANOTUBES PHOTOVOLTAIC power generation HETEROJUNCTIONS PHOTOLUMINESCENCE ELECTRIC fields

Characteristics of the quasi-16-day wave in the mesosphere and lower thermosphere region as revealed by meteor radar,Aura satellite,and MERRA2.reanalysis data from 2.08 to 2.17

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Earth and Planetary Physics 2020年第3期4卷 274-284页

作者： Yun Gong Zheng Ma Chun Li XieDong Lv ShaoDong Zhang QiHou Zhou ChunMing Huang KaiMing Huang You Yu GuoZhu Li School of Electronic information Wuhan UniversityWuhan 430079China key laboratory of Geospace Environment and Geodesy Ministry of EducationWuhan 430079China state key {2. of information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhan 430079China Electrical and Computer Engineering Department Miami UniversityOxfordOhioUSA key laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China

This study presents an analysis of the quasi-16-day wave(Q16DW)at three stations in the middle latitudes by using a meteor radar chain in conjunction with Aura Microwave Limb Sounder temperature data and MERRA2.Modern-Era Retrospective Analysis for Research and Applications,Version 2.reanalysis data from 2.08 to *** radar chain consists of three meteor radar stations located at Mohe(MH,53.5°N,12..3°E),Beijing(BJ,40.3°N,116.2.E),and Wuhan(WH,30.5°N,114.6°E).The Q16DW wave exhibits similar seasonal variation in the neutral wind and temperature,and the Q16DW amplitude is generally strong during winter and weak around *** Q16DW at BJ was found to have secondary enhancement around September in the zonal wind,which is rarely reported at similar *** latitudinal variations of the Q16DW in the neutral wind and temperature are quite *** Q16DW at BJ is the most prominent in both neutral wind components among the three stations and the Q16DW amplitudes at MH and WH are comparable,whereas the wave amplitude in temperature decreases with decreasing *** quasi-geostrophic refractive index squared at the three stations in the period from 2.08 to 2.17 was *** results indicate that the Q16DW in the mesosphere and lower thermosphere(MLT)at MH has a limited contribution from the lower *** March and October,the Q16DW in the troposphere at BJ can propagate upward into the MLT region,whereas at WH,the contribution to the Q16DW in the MLT region is largely from the mesosphere.

关键词： quasi-16-day waves seasonal variations meteor radar winds Aura MLS temperature generation mechanisms