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Now showing items 1 - 11 of 11

  • Design of BPS digital frontend for software defined radio receiver

    Wang Hong-mei   Kim, Jae-hyung   Wang Fa-guang   Lee, Sang-hyuk   Wang Xue-song  

    In radio receivers, complete implementation of the software defined radio (SDR) concept is mainly limited by frontend. Based on bandpass sampling (BPS) theory, a flexible digital frontend (DFE) platform for SDR receiver is designed. In order to increase the processing speed, Gigabit Ethernet was applied in the platform at speed of 5x10(8) bit/s. By appropriate design of interpolant according to the position of input RF signals, multi-band receiving can be realized in the platform with suppression more than 35 dB without changing hardware.
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  • Tribological properties of DLC films prepared by magnetron sputtering

    Wang Hong-mei   Zhang Wei   Yu He-long   Liu Qing-liang  

    Two kinds of diamond-like carbon films containing Ti, C and Ti, Cr, C were prepared by magnetron sputtering PVD. The microstructure and elemental composition of the films were characterized by atomic-force microscope (AFM) and auger electron spectrometer (AES), the hardness and modulus were analyzed by nano-indentation, and the tribological properties of the DLC films sliding against GCr15 ball at various loads were measured on a universal reciprocating friction and wear tester. It was found that a compact and gradient diamond-like carbon film was formed on the Si surface by magnetron sputtering. Ti, C DLC films showed excellent wear resistance because of higher value of H/E, the friction coefficient was 0.1 similar to 0.2 at various loads and the wear rate was in the level of 10-7mm3/m. Element Cr improved the hardness, the modulus and the roughness, but reduced the wear resistance of Ti, Cr, C DLC films. (C) 2011 Published by Elsevier B.V. Selection and/or peer-review under responsibility of Selection and/or peer-review under responsibility of Lanzhou Institute of Physics, China.
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  • Similarity measure application to fault detection of flight system

    Kim, J. H.   Lee, S. H.   Wang Hong-mei  

    Fault detection technique is introduced with similarity measure. The characteristics of conventional similarity measure based on fuzzy number are discussed. With the help of distance measure, similarity measure is constructed explicitly. The designed distance-based similarity measure is applicable to general fuzzy membership functions including non-convex fuzzy membership function, whereas fuzzy number-based similarity measure has limitation to calculate the similarity of general fuzzy membership functions. The applicability of the proposed similarity measure to general fuzzy membership structures is proven by identifying the definition. To decide fault detection of flight system, the experimental data (pitching moment coefficients and lift coefficients) are transformed into fuzzy membership functions. Distance-based similarity measure is applied to the obtained fuzzy membership functions, and similarity computation and analysis are obtained with the fault and normal operation coefficients.
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  • Fault detection method with PCA and LDA and its application to induction motor

    Jung, D. Y.   Lee, S. M.   Wang Hong-mei   Kim, J. H.   Lee, S. H.  

    A feature extraction and fusion algorithm was constructed by combining principal component analysis (PCA) and linear discriminant analysis (LDA) to detect a fault state of the induction motor. After yielding a feature vector with PCA and LDA from current signal that was measured by an experiment, the reference data were used to produce matching values. In a diagnostic step, two matching values that were obtained by PCA and LDA, respectively, were combined by probability model, and a faulted signal was finally diagnosed. As the proposed diagnosis algorithm brings only merits of PCA and LDA into relief, it shows excellent performance under the noisy environment. The simulation was executed under various noisy conditions in order to demonstrate the suitability of the proposed algorithm and showed more excellent performance than the case just using conventional PCA or LDA.
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    Li Hong-jian   Wang Meng-hui   Wang Hong-mei   Kong Jian-qiong   Li Nanfang  

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  • Genetic diversity and genetic differentiation of natural Pinus koraiensis population

    Han Shi-jie   Wang Hong-mei  

    Genetic diversities and genetic differentiations of the four Pinus koraiensis populations (Gaofeng Forestry Farm at Tangwanghe in Yichun City, Erdaobaihe Town in the Changbai Mountains, Shengshan Forestry Farm in Heihe City. in China, and the suburb of Vladivostok City in Russia) were analyzed by using ISSR-PCR technique. The results of 15 printers amplification showed that the ratio of polymorphic site of P. koraiensis population was 60.7%. Each printer had 3.6 polymorphic sites. The diversity levels of the four P. koraiensis populations were rather higher compared with those of other Pinaceae species. The genetic diversity levels of P. koraiensis Populations grown in the center region were higher than those grown in the edge zone. The genetic diversity of P koraiensis mainly came from the interior of the Population, accounting for 73% of total genetic diversity. There were no positive correlation between genetic distances and geographical distances for the four P. koraiensis Populations. The gradual decrease of natural distribution region of P. koraiensis was due to anthropic destroy and environmental factors (i.e. fire aid wind throw), rather than the lower genetic diversity.
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    Ma Xuan   Li Hong-jian   Wang Hong-mei   Wang Meng-hui   Wang Lei   Hu Jun-li   Li Nang-fang  

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  • Computational prediction of over-annotated protein-coding genes in the genome of Agrobacterium tumefaciens strain C58

    Yu Jia-Feng   Sui Tian-Xiang   Wang Hong-Mei   Wang Chun-Ling   Jing Li   Wang Ji-Hua  

    Agrobacterium tumefaciens strain C58 is a type of pathogen that can cause tumors in some dicotyledonous plants. Ever since the genome of A. tumefaciens strain C58 was sequenced, the quality of annotation of its protein-coding genes has been queried continually, because the annotation varies greatly among different databases. In this paper, the questionable hypothetical genes were re-predicted by integrating the TN curve and Z curve methods. As a result, 30 genes originally annotated as "hypothetical" were discriminated as being non-coding sequences. By testing the re-prediction program 10 times on data sets composed of the function-known genes, the mean accuracy of 99.99% and mean Matthews correlation coefficient value of 0.9999 were obtained. Further sequence analysis and COG analysis showed that the re-annotation results were very reliable. This work can provide an efficient tool and data resources for future studies of A. tumefaciens strain C58.
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    Lin Na   Yao Xiao-guang   Zhou Ling   Wang Hong-mei   Hong Jing   Li Nan-fang   Li Nan-fang  

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  • Development of Dipolar Proton Transfer Reaction Mass Spectrometer for Real-time Monitoring of Volatile Organic Compounds in Ambient Air

    Zhang Qiang-Ling   Zou Xue   Liang Qu   Zhang Ya-Ting   Yi Ming-Jian   Wang Hong-Mei   Huang Chao-Qun   Shen Cheng-Yin   Chu Yan-Nan  

    Volatile organic compounds (VOCs) in ambient air can participate in photochemical reactions, which lead to the generation of secondary pollutants such as ozone and aerosol. So real-time and accurate monitoring of atmospheric VOCs plays an important role in the study of the causes of air pollution. On the basis of proton transfer reaction mass spectrometry (PTR-MS) research, a novel dipolar proton transfer reaction mass spectrometer (DP-PTR-MS) for real-time and on-line monitoring of atmospheric VOCs was developed. Compared with conventional PTR-MS with one kind of reagent ion H3O+, DP-PTR-MS had three kinds of reagent ions H3O+,OH-,(CH3)(2)COH+, which could be switched according to the actual detection need. So DP-PTR-MS can improve the qualitative ability and expand the detection range effectively. The reagent ion H3O+ can be used for detecting VOCs whose proton affinities are greater than that of H2O. The reagent ion OH- can be used to identify VOCs cooperating with the reagent ion H3O+, and can also be used for detecting some inorganic substances such as CO2. The reagent ion (CH3)(2)COH+ can be used for accurately detecting NH3 under interference elimination circumstances. The limit of detection (LOD) and sensitivity of DP-PTR-MS were measured by using six kinds of standard gases. The results showed that the LOD for detecting toluene was 7 x 10(-12) (V/V) and the sensitivity for detecting ammonia reached 126 cps/10(-9) (V/V). The ambient air in Hefei city was on-line and real-time monitored for continuous 78 h with DP-PTR-MS. The results showed that the newly developed DP-PTR-MS could be used for long-term and real-time monitoring atmospheric VOCs at the concentration of 10(-12) (V/V) level. DP-PTR-MS is an important tool to the study of the causes of atmospheric pollution and the monitoring of trace VOCs emissions.
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  • Rapid detection of foot-and-mouth disease virus using reverse transcription recombinase polymerase amplification combined with a lateral flow dipstick

    Wang Hong-mei   Zhao Gui-min   Hou Pei-li   Yu Li   He Cheng-qiang   He Hong-bin  

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