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Search Results: 1 - 10 of 231366 matches for " Yan Wei Zhao;Min Zhang;Xupu Geng;Ping Zhou "
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A Comprehensive Facet Model for Bistatic SAR Imagery of Dynamic Ocean Scene
Yan Wei Zhao;Min Zhang;Xupu Geng;Ping Zhou
PIER , 2012, DOI: 10.2528/PIER11100910
Abstract: A comprehensive facet model for bistatic synthetic aperture radar (Bis-SAR) imagery of dynamic ocean scene is presented in this paper. An efficient facet scattering model is developed to calculate the radar cross section (RCS) of the ocean surface for Bis-SAR firstly. Further more, this facet model is combined with a bistatic velocity bunching ($VB$) modulation of long ocean waves to obtain the Bis-SAR intensity expression in image plane of ocean scene. The displacement of the scatter elements in the image plane and the degradation of radar resolution in azimuth direction are quantificationally analyzed. Finally, Bis-SAR imagery simulations of ocean surface are illustrated, proving the validity and practicability of the presented algorithms.
Investigation on Doppler Spectral Characteristics of Electromagnetic Backscattered Echoes from Dynamic Nonlinear Surfaces of Finite-Depth Sea
Ding Nie;Min Zhang;Xupu Geng;Ping Zhou
PIER , 2012, DOI: 10.2528/PIER12062509
Abstract: The Doppler spectral characteristics of electromagnetic backscattered echoes from dynamic nonlinear surfaces of finite-depth sea is investigated with the second-order small-slope approximation (SSA-II). The revised nonlinear hydrodynamic choppy wave model (CWM) combining with an experiment-verified shoaling coefficient is utilized to model the finite-depth sea wave profiles, and the simulated surfaces of finite-depth sea show steeper crests and more flat troughs as depth decreases. First, Comparison of the Doppler spectra for linear sea surfaces and nonlinear choppy sea surfaces shows that nonlinear hydrodynamic effect greatly enhances the Doppler shift and the Doppler spectrum bandwidth, and the predicted results agree well with the rigorous numerical model data. The Doppler spectra of backscattered echoes from finite-depth sea with different depths are further evaluated. At small incident angles, the Doppler shifts and the spectra bandwidths are much lower for shallower sea, and the opposite situation can be gradually observed for increased incident angles. This indicates that the nonlinear wave-wave interactions among waves occur more frequently in finite-depth sea and the long waves will be suppressed while shorter wind waves will be boosted in shallower water. Moreover, the dependence of the Doppler spectral characteristics on polarization is also discussed.
Genome Sequence and Transcriptome Analysis of the Radioresistant Bacterium Deinococcus gobiensis: Insights into the Extreme Environmental Adaptations
Menglong Yuan, Ming Chen, Wei Zhang, Wei Lu, Jin Wang, Mingkun Yang, Peng Zhao, Ran Tang, Xinna Li, Yanhua Hao, Zhengfu Zhou, Yuhua Zhan, Haiying Yu, Chao Teng, Yongliang Yan, Shuzhen Ping, Yingdian Wang, Min Lin
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0034458
Abstract: The desert is an excellent model for studying evolution under extreme environments. We present here the complete genome and ultraviolet (UV) radiation-induced transcriptome of Deinococcus gobiensis I-0, which was isolated from the cold Gobi desert and shows higher tolerance to gamma radiation and UV light than all other known microorganisms. Nearly half of the genes in the genome encode proteins of unknown function, suggesting that the extreme resistance phenotype may be attributed to unknown genes and pathways. D. gobiensis also contains a surprisingly large number of horizontally acquired genes and predicted mobile elements of different classes, which is indicative of adaptation to extreme environments through genomic plasticity. High-resolution RNA-Seq transcriptome analyses indicated that 30 regulatory proteins, including several well-known regulators and uncharacterized protein kinases, and 13 noncoding RNAs were induced immediately after UV irradiation. Particularly interesting is the UV irradiation induction of the phrB and recB genes involved in photoreactivation and recombinational repair, respectively. These proteins likely include key players in the immediate global transcriptional response to UV irradiation. Our results help to explain the exceptional ability of D. gobiensis to withstand environmental extremes of the Gobi desert, and highlight the metabolic features of this organism that have biotechnological potential.
Genome Biology of Actinobacillus pleuropneumoniae JL03, an Isolate of Serotype 3 Prevalent in China
Zhuofei Xu, Yan Zhou, Liangjun Li, Rui Zhou, Shaobo Xiao, Yun Wan, Sihua Zhang, Kai Wang, Wei Li, Lu Li, Hui Jin, Mingsong Kang, Baolige Dalai, Tingting Li, Lei Liu, Yangyi Cheng, Lei Zhang, Tao Xu, Huajun Zheng, Shiying Pu, Bofei Wang, Wenyi Gu, Xiang-Lin Zhang, Geng-Feng Zhu, Shengyue Wang, Guo-Ping Zhao, Huanchun Chen
PLOS ONE , 2008, DOI: 10.1371/journal.pone.0001450
Abstract: Actinobacillus pleuropneumoniae is the etiologic agent of porcine contagious pleuropneumonia, a cause of considerable world wide economic losses in the swine industry. We sequenced the complete genome of A. pleuropneumoniae, JL03, an isolate of serotype 3 prevalent in China. Its genome is a single chromosome of 2,242,062 base pairs containing 2,097 predicted protein-coding sequences, six ribosomal rRNA operons, and 63 tRNA genes. Preliminary analysis of the genomic sequence and the functions of the encoded proteins not only confirmed the present physiological and pathological knowledge but also offered new insights into the metabolic and virulence characteristics of this important pathogen. We identified a full spectrum of genes related to its characteristic chemoheterotrophic catabolism of fermentation and respiration with an incomplete TCA system for anabolism. In addition to confirming the lack of ApxI toxin, identification of a nonsense mutation in apxIVA and a 5′-proximal truncation of the flp operon deleting both its promoter and the flp1flp2tadV genes have provided convincing scenarios for the low virulence property of JL03. Comparative genomic analysis using the available sequences of other serotypes, probable strain (serotype)-specific genomic islands related to capsular polysaccharides and lipopolysaccharide O-antigen biosyntheses were identified in JL03, which provides a foundation for future research into the mechanisms of serotypic diversity of A. pleuropneumoniae.
High-resolution angle-resolved photoemission spectroscopy study of the electronic structure of EuFe2As2
Bo Zhou,Yan Zhang,Le-Xian Yang,Min Xu,Cheng He,Fei Chen,Jia-Feng Zhao,Hong-Wei Ou,Jia Wei,Bin-Ping Xie,Tao Wu,Gang Wu,Masashi Arita,Kenya Shimada,Hirofumi Namatame,Masaki Taniguchi,X. H. Chen,D. L. Feng
Physics , 2010, DOI: 10.1103/PhysRevB.81.155124
Abstract: We report the high-resolution angle-resolved photoemission spectroscopy studies of electronic structure of EuFe2As2. The paramagnetic state data are found to be consistent with density-functional calculations. In the antiferromagnetic ordering state of Fe, our results show that the band splitting, folding, and hybridization evolve with temperature, which cannot be explained by a simple folding picture. Detailed measurements reveal that a tiny electron Fermi pocket and a tiny hole pocket are formed near (pi,pi) in the (0,0)-(pi,pi) direction, which qualitatively agree with the results of quantum oscillations, considering kz variation of Fermi surface. Furthermore, no noticeable change within the energy resolution is observed across the antiferromagnetic transition of Eu2+ ordering, suggesting weak coupling between Eu sublattice and FeAs sublattice.
Research on high-T-c SQUID based non-destructive evaluation
Research on high-Tc SQUID based non-destructive evaluation

Wang Hui-Wu,Kong Xiang-Yan,Ren Yu-Feng,Yu Hong-Wei,Ding Hong-Sheng,Zhao Shi-Ping,Chen Geng-Hu,Zhou Yue-Liang,Zhang Li-Hu,He Yu-Sheng,Yang Qian-Sheng,

中国物理 B , 2004,
Abstract: A non-destructive evaluation system based on high-T_c dc-SQUID (superconducting quantum interference device) incorporating a gradient field excitation has been built. By using this system a 1mm-diameter hole at a depth of 2mm inside an aluminium plate at room temperature can be easily detected and imaged in an unshielded environment. The relation between the spatial resolution, or the smallest detectable flaw size, and experimental parameters is briefly analysed in terms of a simple metal ring model. The result shows that the spatial resolution depends strongly on the sensor-sample separation as well as on some other parameters, such as signal-to-noise ratio of excitation, excitation frequency and material conductivity.
Electron field emission from single-walled carbon nanotube nonwoven
Song Li,Liu Shuang,Zhang Geng-Min,Liu Li-Feng,Ma Wen-Jun,Liu Dong-Fang,Zhao Xiao-Wei,Luo Shu-Dong,Zhang Zeng-Xing,Xiang Yan-Juan,Shen Jun,Zhou Jian-Jun,Wang Gang,Zhou Wei-Ya,

中国物理 B , 2006,
Abstract: Field emission from single-walled carbon nanotube (SWNT) nonwoven has been investigated under high vacuum with different vacuum gaps. A low turn-on electric field of 1.05\,V/$\mu $m is required to reach an emission current density of 10 $\mu $A/cm$^{2}$. An emission current density of 10 mA/cm$^{2}$ is obtained at an operating electric field of 1.88\,V/$\mu $m. No current saturation is found even at an emission current of 5\,mA. With the vacuum gap increasing from 1 to 10 mm, the turn-on field decreases monotonically from 1.21 to 0.68\,V/$\mu $m, while the field amplification is augmented. The good field-emission behaviour is ascribed to the combined effects of the intrinsic field emission of SWNT and the waved topography of the nonwoven.
Quantum blockade and loop current induced by a single lattice defect in graphene nanoribbons
Jie-Yun Yan,Ping Zhang,Bo Sun,Hai-Zhou Lu,Zhigang Wang,Suqing Duan,Xian-Geng Zhao
Physics , 2008, DOI: 10.1103/PhysRevB.79.115403
Abstract: We investigate theoretically the electronic transport properties in narrow graphene ribbons with an adatom-induced defect. It is found that the lowest conductance step of a metallic graphene nanoribbon may develop a dip even down to zero at certain values of the Fermi energy due to the defect. Accompanying the occurrence of the conductance dip, a loop current develops around the defect. We show how the properties of the conductance dip depend on the parameters of the defect, such as the relative position and severity of the defect as well as the width and edges of the graphene ribbons. In particular, for metallic armchair-edges graphene nanoribbons, whether the conductance dip appears or not, they can be controlled by choosing the position of the single defect.
Leber''s hereditary optic neuropathy may be associated with the mitochondrial tRNAGlu A14693G mutation in three Chinese families

ZHANG Yong-Mei,JI Yan-Chun,LIU Xiao-Ling,ZHOU Xiang-Tian,ZHAO Fu-Xin,SUN Yan-Hong,WEI Qi-Ping,ZHANG Juan-Juan,LIU Yan,QU Jia,GUAN Min-Xin,Zhejiang Provincial Key Laboratory of Medical Genetics,School of Life Sciences,Wenzhou Medical College,Wenzhou,China,School of Ophthalmology,Optometry,Wenzhou,

遗传 , 2010,
Abstract: We reported here the clinical, genetic and molecular characterization of three Han Chinese families with Leber’s hereditary optic neuropathy. Ophthalmologic examinations revealed the variable severity and age-at-onset of visual loss among probands and other matrilineal relatives of these families. Strikingly, these families exhibited extremely low penetrances of visual impairment. Sequence analysis of complete mitochondrial genomes in these pedigrees identified the known homoplasmic tRNAGlu A14693G mutation and distinct sets of polymorphism belonging to haplogroups Y1b, Y1 and Y1, respectively. The A14693G mutation occurs at the extremely conserved nucleotide (conventional position 54) of tRNAGlu. Thus, this mutation may alter structural formation and stabilization of functional tRNAs, thereby leading to a failure in tRNA metabolism and mitochondrial dysfunction involved in visual impairment. However, none of other variants showed the evolutionary conservation and functional significance. These observations suggested that the tRNAGlu A14693G mutation may be involved in the pathogenesis of optic neuropathy in these families.
Genome-wide investigation and functional characterization of the β-ketoadipate pathway in the nitrogen-fixing and root-associated bacterium Pseudomonas stutzeri A1501
Danhua Li, Yongliang Yan, Shuzhen Ping, Ming Chen, Wei Zhang, Liang Li, Wenna Lin, Lizhao Geng, Wei Liu, Wei Lu, Min Lin
BMC Microbiology , 2010, DOI: 10.1186/1471-2180-10-36
Abstract: In this report, we performed a genome-wide analysis of the benzoate and 4-hydroxybenzoate catabolic pathways of Pseudomonas stutzeri A1501, with a focus on the functional characterization of the β-ketoadipate pathway. The P. stutzeri A1501 genome contains sets of catabolic genes involved in the peripheral pathways for catabolism of benzoate (ben) and 4-hydroxybenzoate (pob), and in the catechol (cat) and protocatechuate (pca) branches of the β-ketoadipate pathway. A particular feature of the catabolic gene organization in A1501 is the absence of the catR and pcaK genes encoding a LysR family regulator and 4-hydroxybenzoate permease, respectively. Furthermore, the BenR protein functions as a transcriptional activator of the ben operon, while transcription from the catBC promoter can be activated in response to benzoate. Benzoate degradation is subject to carbon catabolite repression induced by glucose and acetate in A1501. The HPLC analysis of intracellular metabolites indicated that low concentrations of 4-hydroxybenzoate significantly enhance the ability of A1501 to degrade benzoate.The expression of genes encoding proteins involved in the β-ketoadipate pathway is tightly modulated by both pathway-specific and catabolite repression controls in A1501. This strain provides an ideal model system for further study of the evolution and regulation of aromatic catabolic pathways.Aromatic compounds, one of the most abundant classes of natural carbon compounds, accumulate primarily due to the degradation of plant-derived molecules (e.g., lignin). These structurally diverse compounds are independently converted to a small number of structurally simpler common intermediates, such as catechol and protocatechuate, which are subsequently metabolized to tricarboxylic acid intermediates via the β-ketoadipate pathway [1-3]. Therefore, many soil bacteria are characterized by considerable metabolic flexibility and physiological adaptability with a minimum number of functional protein
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