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A New Weighting Function for Estimating Microwave Sounding Unit Channel 4 Temperature Trends Simulated by CMIP5 Climate Models

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Advances in Atmospheric Sciences 2013年第3期30卷 779-789页

作者：张选泽郑小谷杨赤骆三 College of Global Change and Earth System Science Beijing Normal University College of Atmospheric Sciences Lanzhou University

A new static microwave sounding unit （MSU） channel 4 weighting function is obtained from using Coupled Model Inter-comparison Project, Phase 5 （CMIP5） historical multimodel simulations as inputs into the fast Radiative Transfer Model for TOVS （RTTOV v10）. For the same CMIP5 model simulations, it is demonstrated that the computed MSU channel 4 brightness temperature （T4） trends in the lower stratosphere over both the globe and the tropics using the proposed weighting function are equivalent to those calculated by RTTOV, but show more cooling than those computed using the traditional UAH （University of Alabama at Huntsville） or RSS （Remote Sensing Systems in Santa Rosa, California） static weighting functions. The new static weighting function not only reduces the computational cost, but also reveals reasons why trends using a radiative transfer model are different from those using a traditional static weighting function. This study also shows that CMIP5 model simulated T4 trends using the traditional UAH or RSS static weighting functions show less cooling than satellite observations over the globe and the tropics. Although not completely removed, this difference can be reduced using the proposed weighting function to some extent, especially over the tropics. This work aims to explore the reasons for the trend differences and to see to what extent they are related to the inaccurate weighting functions. This would also help distinguish other sources for trend errors and thus better understand the climate change in the lower stratosphere.

关键词： CMIP5 RTTOV MSU weighting function lower stratospheric temperature variability

Scattering properties of polluted dust in 1.6-μm wavelength

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Chinese Physics B 2014年第10期23卷 130-135页

作者：范萌陈良富李莘莘陶金花苏林邹铭敏 State key Laboratory of Remote Sensing Science Institute of Remote Sensing and Digital EarthChinese Academy of Sciences University of Chinese Academy of Sciences Rollins School of Public Health Emory University

Three typical polluted dust particles （i.e., single coated dust, two-sphere/spheroid system, and coated dust with ag- gregate） including internal and semi-external mixtures are modeled, and their scattering properties at 1.6-μm wavelength are calculated by using the generalized multi-sphere Mie-solution （GMM） method. We investigate the influences of par- ticle size, morphology, and chemical composition on the scattering parameters of polluted dust particles. The analysis results demonstrate that the single scattering albedo of coated dust is much smaller than that of pure dust, especially for the spheroidal black carbon （BC） coated dust. When a dust particle semi-mixes with another aerosol particle to form a two-sphere/spheroid system, its scattering properties are much more sensitive to the size and species of monomers than the monomer shape. If an aggregated BC attaches to the coated dust, the scattering properties of whole particle mainly depend on the host particle （coated dust）.

关键词： scattering properties polluted dust generalized multi-sphere Mie solution method

Wind energy and wave energy resources assessment in the East China Sea and South China Sea

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Science China(Technological Sciences) 2012年第1期55卷 163-173页

作者： ZHENG ChongWei ZHUANG Hui LI Xin LI XunQiang Institute of Meteorology in Science and Technology University of PLA Nanjing 211101 China Unit 12 No. 92538 of PLA Dalian 116041 China Unit No. 92962 of PLA Guangzhou 510320 China

In this paper, the third-generation wave model WAVEWATCH-Ⅲ （WW3） was used to simulate the wave field of the East China Sea and South China Sea from January 1988 to December 2009, with wind input of CCMP wind field. Then, the wind energy density and wave energy density were calculated by using the simulated 22-years＇ wave-field data and CCMP data. By synthetically considering the size of energy density, the frequency of energy level and the stability of energy density, the resources of wind energy and wave energy in the East China Sea and South China Sea were analyzed and regionalized. The result can be a guide to searching location of wind ＆ wave power plant.

关键词： East China Sea and South China Sea wind energy resources wave energy resources power plant location

Improvement of breakdown characteristics of an A1GaN/GaN HEMT with a U-type gate foot for millimeter-wave power application

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Chinese Physics B 2012年第12期21卷 531-537页

作者：孔欣魏珂刘果果刘新宇 Microwave Devices and Integrated Circuits Department Key Laboratory of Microelectronics Device and Integrated TechnologyInstitute of MicroelectronicsChinese Academy of SciencesBeijing 100029China

In this study, the physics-based device simulation tool Silvaco ATLAS is used to characterize the electrical properties of an AlGaN/GaN high electron mobility transistor （HEMT） with a U-type gate foot. The U-gate AlGaN/GaN HEMT mainly features a gradually changed sidewall angle, which effectively mitigates the electric field in the channel, thus obtaining enhanced off-state breakdown characteristics. At the same time, only a small additional gate capacitance and decreased gate resistance ensure excellent RF characteristics for the U-gate device. U-gate AlGaN/GaN HEMTs are feasible through adjusting the etching conditions of an inductively coupled plasma system, without introducing any extra process steps. The simulation results are confirmed by experimental measurements. These features indicate that U-gate A1GaN/GaN HEMTs might be promising candidates for use in millimeter-wave power applications.

关键词： AlGaN/GaN HEMT breakdown characteristics millimeter-wave U-type gate foot

Modeling and Calculation of Impact Friction Caused by Corner Contact in Gear Transmission

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Chinese Journal of Mechanical Engineering 2014年第5期27卷 958-964页

作者： ZHOU Changjiang CHEN Siyu national Engineering research Center for High Efficiency Grinding Hunan University State key Laboratory of High Performance Complex Manufacturing Central South University

Corner contact in gear pair causes vibration and noise,which has attracted many ***,teeth errors and deformation make it difficulty to determine the point situated at corner contact and study the mechanism of teeth impact friction in the current *** on the mechanism of corner contact,the process of corner contact is divided into two stages of impact and scratch,and the calculation model including gear equivalent error-combined deformation is established along the line of *** to the distributive law,gear equivalent error is synthesized by base pitch error,normal backlash and tooth profile modification on the line of *** combined tooth compliance of the first point lying in corner contact before the normal path is inversed along the line of action,on basis of the theory of engagement and the curve of tooth synthetic *** secondarily the equivalent error with the combined deflection,the position standard of the point situated at corner contact is *** the impact positions and forces,from the beginning to the end during corner contact before the normal path,are calculated *** to the above results,the lash model during corner contact is founded,and the impact force and frictional coefficient are quantified.A numerical example is performed and the averaged impact friction coefficient based on the presented calculation method is *** research obtains the results which could be referenced to understand the complex mechanism of teeth impact friction and quantitative calculation of the friction force and coefficient,and to gear exact design for tribology.

关键词： gear transmission corner contact oblique impact model impact friction frictional coefficient

Flat Supercontinuum Generation within the Telecommunication Wave Bands in a Photonic Crystal Fiber with Central Holes

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Chinese Physics Letters 2012年第5期29卷 126-128页

作者： HAN Ying HOU Lan-Tian ZHOU Gui-Yao YUAN Jin-Hui XIA Chang-Ming WANG Wei WANG Chao HOU Zhi-Yun College of Information Science and Engineering Yanshan UniversityQinhuangdao 066004 key Laboratory of Metastable Material Science and Technology Yanshan UniversityQinhuangdao 066004 School of Information and Optoelectronic Science and Engineering South China Normal UniversityGuangzhou 510006 State key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and TelecommunicationsBeijing 100876

Flat supercontinuum in the telecommunication wave bands of E+S+C is generated by coupling a train of femtosecond pulses generated by a mode-locked Ti:sapphire laser into the fundameutal mode of a photonic crystal fiber with central holes fabricated in our lab. The pulse experiences the anomalous dispersion regime,and the soliton dynamic effect plays an important role in supercontinuum *** output spectrum in the wavelength range of 1360 1565nm does not include significant ripples due to higher pump peak power,and the normalized intensity shows less fluctuation.

关键词： pump Crystal soliton

Effects of cold rolling deformation on microstructure,hardness,and creep behavior of high nitrogen austenitic stainless steel

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Chinese Physics B 2014年第2期23卷 379-384页

作者：孙世成孙贵训江忠浩季长涛刘家安连建设 key Laboratory of Automobile Materials College of Materials Science and EngineeringJilin UniversityNanling Campus key Laboratory of Advanced Structural Materials Ministry of EducationCollege of Materials Science and EngineeringChangchun University of Technology

Effects of cold rolling deformation on the microstructure, hardness, and creep behavior of high nitrogen austenitic stainless steel （HNASS） are investigated. Microstructure characterization shows that 70% cold rolling deformation results in significant refinement of the microstructure of this steel, with its average twin thickness reducing from 6.4 μm to 14 nm. Nanoindentation tests at different strain rates demonstrate that the hardness of the steel with nano-scale twins （nt-HNASS） is about 2 times as high as that of steel with micro-scale twins （mt-HNASS）. The hardness of nt-HNASS exhibits a pronounced strain rate dependence with a strain rate sensitivity （m value） of 0.0319, which is far higher than that of mt-HNASS （m = 0.0029）. nt-HNASS shows more significant load plateaus and a higher creep rate than mt-HNASS. Analysis reveals that higher hardness and larger m value of nt-HNASS arise from stronger strain hardening role, which is caused by the higher storage rate of dislocations and the interactions between dislocations and high density twins. The more significant load plateaus and higher creep rates of nt-HNASS are due to the rapid relaxation of the dislocation structures generated during loading.

关键词： high nitrogen austenitic stainless steel cold deformation nanoindentation tests creep behavior

Increased performance of an organic light-emitting diode by employing a zinc phthalocyanine based composite hole transport layer

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Chinese Physics B 2013年第12期22卷 431-434页

作者：郭闰达岳守振王鹏陈宇赵毅刘式墉 Department of State key Laboratory on Integrated Optoelectronics College of Electronics Science and EngineeringJilin University Department of State key Laboratory on Integrated Optoelectronics College of Electronics Science and Engineering Jilin University

We demonstrate that the electroluminescent performances of organic light-emitting diodes are significantly improved by employing a zinc phthalocyanine （ZnPc）-based composite hole transport layer （c-HTL）. The optimum ris-（8-hydroxyquinoline）aluminum （Alq3）-based organic light-emitting diode with a c-HTL exhibits a lower turn-on voltage of 2.8 V, a higher maximum current efficiency of 3.40 cd/A and a higher maximum power efficiency of 1.91 lm/W, which are superior to those of the conventional device （turn-on voltage of 3.8 V, maximum current efficiency of 2.60 cd/A, and maximum power efficiency of 1.21 lm/W）. We systematically studied the effects of different kinds of N’-diphenyl-N,N’-bis（1-naphthyl）（1,1’-biphenyl）-4,4’diamine （NPB）：ZnPc c-HTL. Meanwhile, we also investigate their mechanisms different from that in the case of using ZnPc as buffer layer. The specific analysis is based on the absorption spectra of the hole transporting material and current density–voltage characteristics of the corresponding hole-only devices.

关键词： organic light emitting diodes composite hole transport layer zinc phthalocyanine

The Burial of Biogenic Silica, Organic Carbon and Organic Nitrogen in the Sediments of the East China Sea

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Journal of Ocean University of China 2015年第3期14卷 464-470页

作者： WANG Lisha ZHANG Chuansong SHI Xiaoyong College of Chemistry and Chemical Engineering Ocean University of China key Laboratory of Marine Chemistry Theory and Technology Ministry of Education Ocean University of China national Marine Hazard Mitigation Service

We sampled the sediments of the East China Sea during 2005 and 2006, and analysed the contents of the biogenic matters: biogenic silica, organic carbon, and organic nitrogen. From the surface distribution we found the contents of these substances to be in the ranges of 0.72%-1.64%, 0.043%-0.82%, and 0.006%-0.11%, respectively. Their distributions were similar to each other, being high inside the Hangzhou Bay and low outside the bay. The vertical variations of the contents were also similar. In order to discuss the relation between them we analysed the variations of content with depth. They increased in the first 7 cm and then decreased with depth. The peaks were found at depths between 20 to 25 cm. The distribution of carbonate showed an opposite trend to that of biogenic matters. The content of total carbon was relatively stable with respect to depth, and the ratio of high organic carbon to carbonate showed a low burial efficiency of carbonate, which means that the main burial of carbon is organic carbon. In order to discuss the source of organic matters, the ratio of organic carbon to organic nitrogen was calculated, which was 8.01 to 9.65, indicating that the organic matter in the sediments was derived mainly from phytoplankton in the seawater.

关键词： burial sediment biogenic matters carbon and nitrogen ratio East China Sea