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Origin of the Novel Magnetoresistance Oscillation of the Two-Dimensional Electron Gas in Al_(x)Ga_(l-x)N/GaN Heterostructures

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Chinese Physics Letters 2001年第12期18卷 1641-1643页

作者： zheng Ze-Wei SHEN Bo JIANG Chun-Ping ZHANG Rong SHI Yi zheng you-Dou zheng Guo-Zhen GUO Shao-Ling CHU Jun-Hao National Laboratory of Solid State Microstructures and Department of Physics Nanjing UniversityNanjing 210093 National Laboratory for Infrared Physics Shanghai Institute of Technical PhysicsChinese Academy of SciencesShanghai 200083

In the magnetotransport measurements of the two-dimensional electron gas (2DEG) in modulation-doped Al_(0.22)Ga_(0.7)sN/C heterostructures, a new magnetoresistance oscillation of the 2DEG is observed at low magnetic fields when the Al_(0.22)Ga_(0.7)sN layer on GaN is partially relaxed. It is thought that the misfit dislocations induced by the partially relaxed Al_(0.22)Ga_(0.7)sN layer modulate the distribution of the piezoelectric polarization-induced charges at the Al0.22Ga0.7sN/GaN heterointerface, and thus produce a strong modulation potential at the heterointerface. The strong modulation potential results in the novel magnetoresistance oscillation of the 2DEG at low magnetic fields.

关键词： N/Ga polarization relaxed

Electrical and Optical Properties of InGaN/AlGaN Double Heterostructure Blue Light-Emitting Diodes

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Chinese Physics Letters 2001年第2期18卷 283-285页

作者： SHEN Bo SHI Hong-Tao ZHANG Rong CHEN Zhi-Zhong zheng you-Dou National Laboratory of Solid State Microstructures and Department of Physics Nanjing UniversityNanjing 210093

Electrical and optical properties of InGaN/AlGaN double heterostructure blue light-emitting diodes were *** of the forward bias current-voltage behaviour of the device demonstrated a departure from the Shockley model of a p-n diode,and it was observed that the dominant mechanism of carrier transport across the junction is associated with carrier *** experiments indicated that there was a main emission band around 2.80 eV and a relatively weaker peak at 3.2 eV.A significant blueshift of the optical emission band was observed,which was consistent with the tunnelling character of electrical ***,the degradation in I-V characteristics and the low resistance ohmic short of the device were observed.

关键词： GaN/AlGaN Shockley ohmic

Variations of Single Nucleotide Polymorphism (SNP) of Hordoindoline a Gene (hina) and Its Relationships with Kernel Hardness in 92 North American Barley Varieties (Hordeum vulgare L.)

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Agricultural Sciences in China 2009年第12期8卷 1440-1447页

作者： CHEN Guo-yue YANG Shi-dong LI Wei-tao LI Wei WEI Yu-ming zheng you-liang Triticeae Research Institute Sichuan Agricultural University Ya'an 625014 P.R.China Key Laboratory of Crop Genetic Resources and Improvement in Southwest China Ministry of Education/Sichuan Agricultural University Ya'an 625014 P.R. China College of Agronomy Sichuan Agricultural University Ya'an 625014 P.R.China

Grain texture in barley （Hordeum vulgare L.） is an important quality character. The single nucleotide polymorphisms （SNPs） in Hordoindoline a （hina） gene and its relationship with hardness index among North American harley cultivars were investigated. The hina genes in 36 cultivars were sequenced for the SNP analyses, and 17 sets of SNP primers were designed to detect the SNP variations of hina locus in 92 North American barley cultivars. SNP detection indicated that there were four haplotypes in the hina genes of 92 barley cultivars, and haplotype 01 and 02 were shared by 68 and 14 cultivars, respectively, suggesting that there was a very limited diversity in hina genes among North American barley cultivars. Despite the wide range in hardness exists in 92 barley cultivars, however, unlike wheat, where a clear relationship has been demonstrated between a number of SNPs in the wheat hardness genes and quality （soft or hard wheat）, there was no such relationship for barley. The genotypes used in this study demonstrated that there was a low level of polymorphism in hina gene in North American barley cultivars and these polymorphisms had no impact on grain hardness.

关键词： barley Hordoindoline a gene hardness SNP haplotype

Spatial and Temporal Variations of Heat Waves in China from 1961 to 2010

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Advances in Climate Change Research 2014年第2期5卷 66-73页

作者： YE Dian-Xiu YIN Ji-Fu CHEN zheng-Hong zheng you-Fei WU Rong-Jun National Climate Center China Meteorological Administration Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration Nanjing University of Information Science and Technology Hubei Service Center for Meteorological Science & Technology Hebei Meteorological Bureau Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Nanjing University of Information Science & Technology

Daily maximum temperatures from 753 stations across China and the heat wave indicators are used to study the temporal and spatial characteristics of heat wave intensity, frequency and heat wave days in China over the period of1961–2010. The results show that high frequency, long duration and strong intensity of heat waves occurred in the Jianghuai area, Jiangnan area, and eastern Sichuan Basin. The highest frequency and the longest duration are located in northern Jiangxi and northern Zhejiang provinces, and the highest intensity in northern Zhejiang province is even more prominent. The frequency, heat wave days and intensity showed a general increasing trend in the past 50 years, while decadal characteristics are also observed with a decreasing trend from the 1960 s to the early 1980 s and increasing trend from the end of the 1980 s to 2010. The regional variations demonstrate a significant increasing trend in the northern and western parts of North China, central-northern part of Northwest China, the central part of South China, the Yangtze River Delta and the southern Sichuan Basin, with an obvious decreasing trend in the southern Huanghuai area, northern Jianghuai area and Hanjiang River Basin.

关键词： heat wave intensity frequency duration

State-of-the-art on theories and applications of cable-driven parallel robots

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Frontiers of Mechanical Engineering 2022年第3期17卷 35-57页

作者： Zhaokun ZHANG Zhufeng SHAO zheng you Xiaoqiang TANG Bin ZI Guilin YANG Clément GOSSELIN Stéphane CARO State Key Laboratory of Tribology Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China Beijing Key Laboratory of Precision/Ultra-Precision Manufacturing Equipment and Control Tsinghua UniversityBeijing 100084China Department of Mechanical Engineering University of MichiganAnn ArborMI 48109USA Department of Precision Instrument Tsinghua UniversityBeijing 100084China School of Mechanical Engineering Hefei University of TechnologyHefei 230009China Ningbo Institute of Industrial Technology Chinese Academy of Sciences(CAS)Ningbo 315201China Department of Mechanical Engineering UniversitéLavalQuebec QC G1V 0A6Canada Laboratory of Digital Sciences of Nantes National Centre for Scientific ResearchNantes 44321France

Cable-driven parallel robot(CDPR)is a type of high-performance robot that integrates cable-driven kinematic chains and parallel mechanism *** inherits the high dynamics and heavy load capacities of the parallel mechanism and significantly improves the workspace,cost and energy efficiency *** a result,CDPRs have had irreplaceable roles in industrial and technological fields,such as astronomy,aerospace,logistics,simulators,and *** follow the cutting-edge trend of rigid-flexible fusion,reflect advanced lightweight design concepts,and have become a frontier topic in robotics *** paper summarizes the kernel theories and developments of CDPRs,covering configuration design,cable-force distribution,workspace and stiffness,performance evaluation,optimization,and motion *** modeling,workspace analysis,and cable-force solution are *** and dynamic modeling methods are *** further promote the development,researchers should strengthen the investigation in configuration innovation,rapid calculation of workspace,performance evaluation,stiffness control,and rigid-flexible coupling *** addition,engineering problems such as cable materials,reliability design,and a unified control framework require attention.

关键词： cable-driven parallel robot kinematics optimization dynamics control

An Algorithm for Detecting Ice Cloud at Different Altitudes by Combining Dual CrIS Full Spectrum Resolution CO2 Channels

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Journal of Tropical Meteorology 2020年第3期26卷 300-310页

作者： WANG Li-wen zheng you-fei TIAN Miao XU Jing-xin Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration Nanjing University of Information Science&TechnologyNanjing 210044 China Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology Nanjing University of Information Science&TechnologyNanjing 210044China Information Engineering Department School of Information and Communication EngineeringUniversity of Electronic Science and Technology of ChinaChengdu 611731 China State Environmental Protection Key Laboratory of Atmospheric Physical Modeling and Pollution Control State Power Environmental Protection Research InstituteNanjing 210031 China

Using infrared sensors to detect ice clouds in different atmospheric layers is still a *** different scattering and absorption properties of longwave and shortwave infrared channels can be utilized to fulfill this *** this study,the release of Suomi-NPP Cross-track Infrared Sounder(Cr IS)full spectrum resolution is used to select and pair channels from longwave(~15μm)and shortwave(~4.3μm)CO2 absorption bands under stricter conditions,so as to better detect ice ***,the differences of the weighting function peaks and cloud insensitive level altitudes of the paired channels are both within 50 h Pa so that the variances due to atmospheric conditions can be *** training data of clear sky are determined by Visible Infrared Imaging Radiometer Suite(VIIRS)cloud mask product and used to find the linear relationship between the paired longwave and shortwave CO2 absorption *** the linear relationship,the so-called cloud emission and scattering index(CESI)is derived to detect ice *** clearly captures the center and the ice cloud features of the Super Typhoon Hato located above 415 h ***,the CESI distributions agree with cloud top pressure from the VIIRS in both daytime and nighttime in different atmospheric layers.

关键词： Cross-track Infrared Sounder Full Spectral Resolution(CrIS FSR) ice cloud detection dual CO2 absorption bands

Genetic Variation in Triticum turgidum L. ssp. turgidum Landraces from China Assessed by EST-SSR Markers

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Agricultural Sciences in China 2008年第9期7卷 1029-1036页

作者： LI Wei DONG Pan WEI Yu-ming CHENG Guo-yue zheng you-liang Key Laboratory of Crop Genetic Resources and Improvement in Southwest China Ministry of Education/Sichuan Agricultural University Ya＇an 625014 P.R.China Triticeae Research Institute Sichuan Agricultural University Dujiangyan 611830 P.R.China College of Agronomy Sichuan Agricultural University Ya＇an 625014 P.R.China

It was helpful for the wheat improvement to evaluate the genetic resources of Triticum turgidum L. ssp. turgidum landraces. In this study, 68 turgidum landraces accessions, belonging to four geographic populations in China, were investigated by using EST-SSR markers. A total of 63 alleles were detected on 22 EST-SSR loci, and the number of alleles on each locus ranged from 1 to 5, with an average of 2.9. The results of the analysis of molecular variance （AMOVA） indicated that 92.5% of the total variations was attributed to the genetic variations within population, whereas only 7.5% variations among populations. Although the four populations had similar genetic diversity parameters, Sichuan population was yet distinguished from other populations when comparing the population samples in pairs. Significant correlations were detected by the statistic analysis among six genetic diversity parameters among each other. The selection difference between heterozygosty and homozygosty was also observed among different EST-SSR locus. The genetic similarity （GS） ranged from 0.18 to 0.98, with the mean of 0.72, and all accessions could be clustered into 7 groups. The dendrogram suggested that the genetic relationships among turgidum accessions evaluated by EST-SSR markers were unrelated to their geographic distributions. These results implied that turgidum landraces from China had the unique characters of genetic diversity.

关键词： T. turgidum L. ssp. turgidum EST-SSR markers genetic variation genetic structure

Evaluation on Chinese Bread Wheat Landraces for Low pH and Aluminum Tolerance Using Hydroponic Screening

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Agricultural Sciences in China 2009年第3期8卷 285-292页

作者： DAI Shou-fen YAN Ze-hong LIU Deng-cai ZHANG Lian-quan WEI Yu-ming zheng you-liang Triticeae Research Institute Sichuan Agricultural University Dujiangyan 611830 P.R.China

Aluminum （Al） toxicity often takes place in acidic soils with a pH of 5.5 or lower. Breeding and cultivation of Al tolerance wheat can partially protect wheat escaping from Al toxicity. The scarcity of the tolerant sources impedes the wheat breeding. In order to find new Al tolerance sources, we screened 173 bread wheat landraces from Tibet of China using hydroponic screening. It was indicated that：（1） There were diversities on the root regenerate length （RRL）. The RRL of a large of landraces were longer than 7.00 cm in pH 7 （58.38%） and pH 4.5 （66.47%）, but shorter than 5.00 cm in pH 4.5 ＋50μM Al^3＋（80.93%）. The low pH showed either promotion or restraining effects depend on landraces, but Al toxicity under low pH only showed restraining effects on the root elongation. （2） There were also diversities on root tolerance index of low pH （RTI 1） or root aluminum tolerance index （RTI2） among cultivars. The RTI1 varied from a narrow range but with relatively high value （0.8722-1.2953） in comparison with that of RTI2 （0.3829-1.0058）, and the RTI1 of approximately 60% landraces was higher than 1.0000, the RTI2 of only 19.07% landraces was higher than 0.7000, suggesting that Al toxicity acted as an important factor for the reduction of the root elongation under acidic soils. （3） The RTI 1 of many wheats was higher than 1.0000, and As2256 and As2295 were the most tolerant for low pH, with RTI1 1.2953 and 1.2925, respectively. （4） Based on RTI2, seven wheats showed similar or higher tolerance to Al toxicity than Chinese Spring （CS）, a known tolerance wheat. Much better tolerance existed in landraces of As1543 and As1242, which can be used as the new parents for Al tolerant breeding.

关键词： bread wheat root regenerate length tolerance index aluminum tolerance hydroponic screening

Improved sensing performance of WO_(3) nanoparticles decorated with Ag and Pt nanoparticles

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Rare Metals 2021年第6期40卷 1642-1650页

作者： Dong-Liang Feng zheng-you Zhu Ling-Ling Du Xia-Xia Xing Chen Wang Jian Chen Yong-Tao Tian Da-Chi Yang Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology and Department of ElectronicsCollege of Electronic Information and Optical EngineeringNankai UniversityTianjin 300350China School of Physics and Engineering and Key Laboratory of Materials Physics Ministry of EducationZhengzhou UniversityZhengzhou 450001China

Gas sensors built with metal oxide semiconductors have attracted tremendous attention due to the growing demand for the detection of inflammable,explosive and toxic ***,to improve the sensing response,WO_(3) nanoparticles decorated with Ag and Pt bimetals(Ag and Pt/WO_(3) NPs)have been developed via combined hydrolysis and hydrothermal *** sensors prototypes show high response to acetone(Ra/Rg=250@100×10^(-6),140℃),which is 6.1 fold as high as that of the pristine WO_(3) NPs(Ra/Rg=41@100×10^(-6),140℃).Moreover,the recovery time of Ag and Pt/WO_(3) NPs was reduced from 138 to 13 s compared with that of the pristine WO_(3) *** improved acetone sensing performance may be attributed to that the chemical and electronic sensitization of Ag and Pt to WO_(3) NPs increases adsorbed oxygen species,speeds up the reaction and thus boosts the sensing *** strategy that decoration of dual precious metals onto WO_(3) NPs improves the acetone sensing performance may be applied to the gas sensors of other sensing materials.

关键词： WO_(3)nanoparticles Ag and Pt bimetals Acetone sensing Chemical sensitization Recovery time