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Search Results: 1 - 10 of 21267 matches for " Kun Tang "
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Some Critical Issues in the Development of Chinese High-Speed Rail: Challenges and Coping Strategies  [PDF]
Min Chen, Hailong Tang, Kun Zhang
Journal of Transportation Technologies (JTTs) , 2014, DOI: 10.4236/jtts.2014.42017
Abstract:

In this paper, several critical issues related to Chinese high-speed rails (CHSR) are analyzed, investigated and discussed, including development background, reasons for high ticket fare, some typical factors that influence the environmental life-cycle assessment, time and cost comparison of typical door-to-door travel routes between different transport modes and complementary strategies among different transport modes. First, the results show that the expanding high-speed rail network increased the pressure on the country's roads in the 2010 spring festival rush period due to the high ticket fare of CHSR. Second, due to lower than expected ridership because of the high ticket price and limited demand in less developed areas, some Chinese CHSR projects have become economically unsustainable. Third, without sufficient ridership and service life, the utilization of HSR was unable to show any advantages in the environmental impact compared with the other transport modes. In addition, the impact of shock from CHSR on Chinese domestic civil airlines is evident when the travel distance is below 1050 km. The key objective of the investigation is to enhance our understanding of the development and operation of Chinese high-speed rail. One of the key contributions of the current paper is the presented suggestions for complementary strategies between different transport modes to make full use of Chinese transportation resources to promote low carbon economy.

Matroidal Structure of Rough Sets from the Viewpoint of Graph Theory
Jianguo Tang,Kun She,William Zhu
Journal of Applied Mathematics , 2012, DOI: 10.1155/2012/973920
Abstract: Constructing structures with other mathematical theories is an important research field of rough sets. As one mathematical theory on sets, matroids possess a sophisticated structure. This paper builds a bridge between rough sets and matroids and establishes the matroidal structure of rough sets. In order to understand intuitively the relationships between these two theories, we study this problem from the viewpoint of graph theory. Therefore, any partition of the universe can be represented by a family of complete graphs or cycles. Then two different kinds of matroids are constructed and some matroidal characteristics of them are discussed, respectively. The lower and the upper approximations are formulated with these matroidal characteristics. Some new properties, which have not been found in rough sets, are obtained. Furthermore, by defining the concept of lower approximation number, the rank function of some subset of the universe and the approximations of the subset are connected. Finally, the relationships between the two types of matroids are discussed, and the result shows that they are just dual matroids.
A New Approach for Using Genome Scans to Detect Recent Positive Selection in the Human Genome
Kun Tang,Kevin R. Thornton,Mark Stoneking
PLOS Biology , 2012, DOI: 10.1371/journal.pbio.0050171
Abstract: Genome-wide scanning for signals of recent positive selection is essential for a comprehensive and systematic understanding of human adaptation. Here, we present a genomic survey of recent local selective sweeps, especially aimed at those nearly or recently completed. A novel approach was developed for such signals, based on contrasting the extended haplotype homozygosity (EHH) profiles between populations. We applied this method to the genome single nucleotide polymorphism (SNP) data of both the International HapMap Project and Perlegen Sciences, and detected widespread signals of recent local selection across the genome, consisting of both complete and partial sweeps. A challenging problem of genomic scans of recent positive selection is to clearly distinguish selection from neutral effects, given the high sensitivity of the test statistics to departures from neutral demographic assumptions and the lack of a single, accurate neutral model of human history. We therefore developed a new procedure that is robust across a wide range of demographic and ascertainment models, one that indicates that certain portions of the genome clearly depart from neutrality. Simulations of positive selection showed that our tests have high power towards strong selection sweeps that have undergone fixation. Gene ontology analysis of the candidate regions revealed several new functional groups that might help explain some important interpopulation differences in phenotypic traits.
DYNAMIC SCALING OF GROWING SURFACES WITH GROWTH INHOMOGENEITIES OF SCREENED COULOMBIC FUNCTION

Tang Gang,Ma Ben-kun,

中国物理 B , 2000,
Abstract: The dynamic scaling properties of growing surfaces with growth inhomogeneities are studied by applying a dynamic renormalization-group analysis to the generalized Kardar-Parisi-Zhang(hereafter abbreviated to KPZ) equation, which contains an additional term of growth inhomogeneities. In a practical crystal growth process, these growth inhomogeneities can be induced by surface impurities and defects and are modeled by a screened Coulomb function in this paper. Our results show that the existence of the growth inhomogeneities can significantly change the dynamic scaling properties of a growing surface and can lead to a rougher surface.
Correlation Analysis of Persistent Heavy Rainfall Events in the Vicinity of the Yangtze River Valley and Global Outgoing Longwave Radiation in the Preceding Month

TANG Yanbing,ZHAO Lu,GAO Kun,

大气科学进展 , 2009,
Abstract: Based on the National Oceanic and Atmospheric Administration (NOAA) daily satellite dataset of global outgoing longwave radiation (OLR) for the period of 1974--2004 and the NCEP-NCAR reanalysis for 1971--2004, the linkage between persistent heavy rainfall (PHR) events in the vicinity of the Yangtze River valley and global OLR leading up to those events (with 1- to 30-day lag) was investigated. The results reveal that there is a significant connection between the initiation of PHR events over the study area and anomalous convective activity over the tropical Indian Ocean, maritime continent, and tropical western Pacific Ocean. During the 30-day period prior to the onset of PHR events, the major significantly anomalous convective centers have an apparent dipole structure, always with enhanced convection in the west and suppressed convection in the east. This dipole structure continuously shifts eastward with time during the 30-day lead period. The influence of the anomalous convective activity over the tropical oceans on the initiation of PHR events over the study area is achieved via an interaction between tropical and extratropical latitudes. More specifically, anomalous convective activity weakens the Walker circulation cell over the tropical Indian Ocean first. This is followed by a weakening of the Indian summer monsoon background state and the excitation and dispersion of Rossby wave activity over Eurasia. Finally, a major modulation of the large scale background circulation occurs. As a result, the condition of a phase-lock among major large scale circulation features favoring PHR events is established over the study area.
A New Approach for Using Genome Scans to Detect Recent Positive Selection in the Human Genome
Kun Tang ,Kevin R Thornton,Mark Stoneking
PLOS Biology , 2007, DOI: 10.1371/journal.pbio.0050171
Abstract: Genome-wide scanning for signals of recent positive selection is essential for a comprehensive and systematic understanding of human adaptation. Here, we present a genomic survey of recent local selective sweeps, especially aimed at those nearly or recently completed. A novel approach was developed for such signals, based on contrasting the extended haplotype homozygosity (EHH) profiles between populations. We applied this method to the genome single nucleotide polymorphism (SNP) data of both the International HapMap Project and Perlegen Sciences, and detected widespread signals of recent local selection across the genome, consisting of both complete and partial sweeps. A challenging problem of genomic scans of recent positive selection is to clearly distinguish selection from neutral effects, given the high sensitivity of the test statistics to departures from neutral demographic assumptions and the lack of a single, accurate neutral model of human history. We therefore developed a new procedure that is robust across a wide range of demographic and ascertainment models, one that indicates that certain portions of the genome clearly depart from neutrality. Simulations of positive selection showed that our tests have high power towards strong selection sweeps that have undergone fixation. Gene ontology analysis of the candidate regions revealed several new functional groups that might help explain some important interpopulation differences in phenotypic traits.
Effects of Nickel Chloride on Histopathological Lesions and Oxidative Damage in the Thymus  [PDF]
Kun Tang, Jian Li, Shuang Yin, Hongrui Guo, Jie Deng, Hengmin Cui
Health (Health) , 2014, DOI: 10.4236/health.2014.621326
Abstract: The purpose of this study was to observe the histopathological lesions and oxidative damage induced by dietary nickel chloride (NiCl2) in the thymus. A total of 280 one-day-old avian broilers were divided into four groups and fed on a corn-soybean basal diet as the control diet or the same basal diet supplemented with 300, 600, and 900 mg/kg of NiCl2 for 42 days. In the NiCl2-treated groups, the broiler weight and thymic relative weight were significantly (P < 0.05 or P < 0.01) decreased. Histopathologically, thymic corpuscles were increased and enlarged; the reticular cells were degenerate and necrotic, and lymphocytes were slightly decreased and loosely arranged in the medulla of thymus in the 600 mg/kg and 900 mg/kg groups. The activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px), and the ability to inhibit hydroxy radical and glutathione (GSH) content were significantly (P < 0.05 or P < 0.01) lower in the NiCl2-treated groups than those in the control group, while MDA content was higher. The above-mentioned results demonstrated that dietary NiCl2 in excess of 300 mg/kg could reduce the broiler weight and thymic relative weight, and cause histopathological lesions and oxidative damage in the thymus, which finally impaired the thymic function.
Automatic landmark annotation and dense correspondence registration for 3D human facial images
Jianya Guo,Xi Mei,Kun Tang
Computer Science , 2012,
Abstract: Dense surface registration of three-dimensional (3D) human facial images holds great potential for studies of human trait diversity, disease genetics, and forensics. Non-rigid registration is particularly useful for establishing dense anatomical correspondences between faces. Here we describe a novel non-rigid registration method for fully automatic 3D facial image mapping. This method comprises two steps: first, seventeen facial landmarks are automatically annotated, mainly via PCA-based feature recognition following 3D-to-2D data transformation. Second, an efficient thin-plate spline (TPS) protocol is used to establish the dense anatomical correspondence between facial images, under the guidance of the predefined landmarks. We demonstrate that this method is robust and highly accurate, even for different ethnicities. The average face is calculated for individuals of Han Chinese and Uyghur origins. While fully automatic and computationally efficient, this method enables high-throughput analysis of human facial feature variation.
Screening for differentially expressed genes in Anoectochilus roxburghii (Orchidaceae) during symbiosis with the mycorrhizal fungus Epulorhiza sp.
Biao Li,MingJuan Tang,Kun Tang,LiFang Zhao,ShunXing Guo
Science China Life Sciences , 2012, DOI: 10.1007/s11427-012-4284-0
Abstract: Mycorrhizal fungi promote the growth and development of plants, including medicinal plants. The mechanisms by which this growth promotion occurs are of theoretical interest and practical importance to agriculture. Here, an endophytic fungus (AR-18) was isolated from roots of the orchid Anoectochilus roxburghii growing in the wild, and identified as Epulorhiza sp. Tissue-cultured seedlings of A. roxburghii were inoculated with AR-18 and co-cultured for 60 d. Endotrophic mycorrhiza formed and the growth of A. roxburghii was markedly promoted by the fungus. To identify genes in A. roxburghii that were differentially expressed during the symbiosis with AR-18, we used the differential display reverse transcription polymerase chain reaction (DDRT-PCR) method to compare the transcriptomes between seedlings inoculated with the fungus and control seedlings. We amplified 52 DDRT-PCR bands using 15 primer combinations of three anchor primers and five arbitrary primers, and nine bands were re-amplified by double primers. Reverse Northern blot analyses were used to further screen the bands. Five clones were up-regulated in the symbiotic interaction, including genes encoding a uracil phosphoribosyltransferase (UPRTs; EC 2.4.2.9) and a hypothetical protein. One gene encoding an amino acid transmembrane transporter was down-regulated, and one gene encoding a tRNA-Lys (trnK) and a maturase K (matK) pseudogene were expressed only in the inoculated seedlings. The possible roles of the above genes, especially the UPRTs and matK genes, are discussed in relation to the fungal interaction. This study is the first of its type in A. roxburghii.
Large-Eddy Simulation of the Three-Dimensional Experiment on Richtmyer-Meshkov Instability Induced Turbulence  [PDF]
Jingsong Bai, Tao Wang, Kun Liu, Lei Li, Min Zhong, Yang Jiang, Mi Tang, Jidong Yu, Xiaoyang Pei, Ping Li
International Journal of Astronomy and Astrophysics (IJAA) , 2012, DOI: 10.4236/ijaa.2012.21005
Abstract: A program MVFT3D of large-eddy simulation is developed and performed to solve the multi compressible Navier- Stokes equations. The SGS dissipation and molecular viscosity dissipation have been analyzed, and the former is much larger than the later. Our test shows that the SGS dissipation of Vreman model is smaller than the Smagorinsky model. We mainly simulate the experiment of fluid instability of shock-accelerated interface by Poggi in this paper. The decay of the turbulent kinetic energy before the first reflected shock wave–mixing zone interaction and its strong enhancement by re-shocks are presented in our numerical simulations. The computational mixing zone width under double re-shock agreement well with the experiment, and the decaying law of the turbulent kinetic energy is consistent with Mohamed and Larue’s investigation. Also, by using MVFT3D we give some simulation results of the inverse Chevron model from AWE. The numerical simulations presented in this paper allow us to characterize and better understand the Richtmyer-Meshkov instability induced turbulence, and the code MVFT3D is validated.
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