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Search Results: 1 - 10 of 104001 matches for " Guochang Zhang "
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Influence of Vertical Resolution on the Validation of Atmospheric Chemistry Instruments  [PDF]
Guochang Zhang
Atmospheric and Climate Sciences (ACS) , 2011, DOI: 10.4236/acs.2011.13011
Abstract: A large number of validation campaigns for atmospheric chemistry instruments are being carried out and more such studies will be performed in the future. The aims of validation are to confirm the accuracy and precision of the measurement of a new instrument. There are many factors that may deteriorate the validation results and one of them is the vertical resolution of instruments when using the profiles intercomparison ap-proach. The influence from the vertical resolution can be eliminated by using the averaging kernel method but it is necessary to find the conditions for using the method. This study simulated the influence of vertical resolution for a certain curvature. The results show that both the curvature of a profile and the difference of vertical resolution between two instruments have positive correlation with the differences between their measurements. The quantitative estimations of influence for some practical vertical resolutions were ob-tained. The combined error of two instruments was defined as the criteria to judge the significance of influ-ence. A case study based on the simulated results was demonstrated to show when the influence from the vertical resolution should be considered and when such influence can be omitted in order to avoid some un-necessary works in validation.
Reproducing Systems Generated by Finite Functions
Guochang Wu,Yadong Zhang
Information Technology Journal , 2012,
Abstract: Applied harmonic analysis plays an important role in engineering such as signal processing, image processing, digital communications, medical imaging and so on. This study has present an overview of all kind of reproducing systems which are obtained by applying a combination of dilations, modulations and translations to a finite family of functions. Five reproducing systems and their applications are mainly introduced as the following: Gabor systems, wavelet systems, wave packet systems, composite dilation wavelet systems and shearlet systems. Present study reviewed their definitions, history and existing known results, respectively. Furthermore, it also discussed their advantages and shortcomings in the engineering applications.

Xu Guochang,Li Meifang,Zhang Zhiyin,

大气科学进展 , 1985,
Abstract: Decadal rainfall data of 228 stations in 1951-1970 and upper-wind records in 1960-1969 published by the Central Meteorological Bureau and relevant provincial organizations are employed in the analysis. It is found that the characteristic features of seasonal variation of the main rain-belts over eastern China to the east of 105°F are quite different from those to the west, over the Qinghai-Xi?hang (Tibetan) Plateau. The eastern rain-belts are closely related to the low level flow convergence lines and significantly influenced by the south Asian high and the western Pacific subtropical high.
The Cardinal Orthogonal Scaling Function in Higher Dimension
Guochang Wu,Yadong Zhang,Zhengxing Cheng
Information Technology Journal , 2009,
Abstract: In this study, the cardinal orthogonal scaling function in higher dimension is classified by the relation the highpass filter coefficient and wavelet`s samples in its integer points, thus, the sampling theorem in the wavelet subspace is obtained. Then, the symmetry property of cardinal orthogonal scaling function is discussed, and some useful characterizations are given. At last, two examples are constructed to prove the theory.
Sampling Theory: From Shannon Sampling Theorem to Compressing Sampling
Wu Guochang,Zhang Yadong,Yang Xiaohui
Information Technology Journal , 2010,
Abstract: It is known that sampling theory lies at the heart of signal processing devices and communication systems. This study presents an account of the current state of sampling theorem after Shannon’s formulation of the sampling theorem. Our emphasis is on some new tends of sampling theory in recent decade. At first, the problem of vector sampling expansion is argued. Secondly, signal reconstruction from local averages is showed. Thirdly, the issue of sampling theorem in the wavelet subspaces is investigated and some results are given. At last, compressed sampling and its two principles are reviewed.
Image Segmentation Based on Visual Attention Mechanism
Qiaorong Zhang,Guochang Gu,Huimin Xiao
Journal of Multimedia , 2009, DOI: 10.4304/jmm.4.6.363-370
Abstract: A new approach for image segmentation based on visual attention mechanism is proposed. Motivated biologically, this approach simulates the bottom-up human visual selective attention mechanism, extracts early vision features of the image and constructs the saliency map. Multiple image features such as intensity, color and orientation in multiple scales are extracted to get some feature maps. The phase spectra of the feature maps are analyzed in frequency spectrum domain. Then the corresponding feature saliency maps are constructed in spatial domain and theses feature saliency maps are combined to an integrated saliency map. According to the saliency map, the salient regions in an image are detected. The image is segmented by seperating the salient regions and the backgroud. This approach has been tested on natrual images.
Establishment ofChlamydomonas reinhardtii chloroplast expression
Guochang Fan,Ning Su,Zhonglin Zhang,Xiangfu Wu,Guifang Shen
Chinese Science Bulletin , 1999, DOI: 10.1007/BF03183484
Abstract: An expression vector pAC III containing the chimeric gene HAV-VP3P1 and HCV-C gene has been constructed and transferred toC. reinhardtii by the biolistic method. The transformants have been identified by PCR, Southern-blotting, Northern-blotting and Western-blotting assays after selecting on resistant medium and incubating in the dark. The results show that the chimeric gene has replaced thechlL gene ofC. reinhardtii chloroplast genome and expressed correctly under the control of theC. reinhardtii chloroplast double promoters 5′chlL-5′atpA. The analysis of SDS-PAGE indicates that the expressed protein accounts for 5.31 % of total soluble protein.
An Improved Computational Approach for Salient Region Detection
Qiaorong Zhang,Haibo Liu,Jing Shen,Guochang Gu
Journal of Computers , 2010, DOI: 10.4304/jcp.5.7.1011-1018
Abstract: Salient region detection in images is very useful for image processing applications like image compressing, image segmentation, object detection and recognition. In this paper, an improved approach to detect salient region is presented. The proposed method can generate a robust saliency map and extract salient regions with precise boundaries. In the proposed method, local saliency, global saliency and rarity saliency of three kinds of low-level feature contrast of intensity, color and orientation are used to compute the visual saliency. A new feature integration strategy is proposed in this paper. This method can select features and compute the weights of the features dynamically by analyzing the effect of different features on the saliency. Then a more robust saliency map is obtained. It has been tested on many images to evaluate the validity and effectiveness of the proposed method. We also compare our method with other salient region detection methods and our method outperforms other methods in detection results.
JIANG Guochang,ZHANG Xiaobing,XU Kuangdi Shanghai University of Technology,Shanghai,China,
JIANG Guochang
,ZHANG Xiaobing,XU Kuangdi Shanghai University of Technology,Shanghai,China

金属学报(英文版) , 1992,
Abstract: Expressing the excess partial molar free energies and integral excess free energy as poly-nome of the composition,then the parameters in the expression of excess partial molarfree energy of C were evaluated based on:the excess partial free energy of C in C-Fe bi-nary alloy:the integral excess free energy of Fe-X binary alloy:the C saturation curveand the iso-activity curve of C (α_c=0.025) in the ternary system.Then the activitycoefficient of X was evaluated with the so-called “I-D” method,by which the componentactivities of every element in the whole molten ternary alloy can be evaluated,and theresults are in good agreement with literature data based on experiment.
Characterization and comparison of Serratia marcescens isolated from edible cactus and from silkworm for virulence potential and chitosan susceptibility
Li, Bin;Yu, Rongrong;Liu, Baoping;Tang, Qiaomei;Zhang, Guoqing;Wang, Yanli;Xie, Guanlin;Sun, Guochang;
Brazilian Journal of Microbiology , 2011, DOI: 10.1590/S1517-83822011000100013
Abstract: representative strains of serratia marcescens from an edible cactus plant and silkworms were characterized and a comparison based on their cellular fatty acid composition, 16s rrna and groe gene sequence analysis as well as silkworm virulence and chitosan susceptibility was carried out. results from this study indicate that there are no significant differences between the phenotypic and molecular characterization, virulence and chitosan susceptibility of the s. marcescens strains from the cactus plant and silkworms. silkworms inoculated with s. marcescens from either plant or silkworm resulted in nearly 100% mortality. chitosan solution exhibited strong antibacterial activity against s. marcescens. this activity increased with the increase of chitosan concentration and incubation time regardless of the strain source. also, the results indicate that the plant associated s. marcescens maybe plays a possible role in the contamination of humans and animals, in particular silkworms, while chitosan showed a potential to control the contamination caused by s. marcescens.
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