Li G.,Shaanxi Institute of Education
Advanced Materials Research | Year: 2012
An efficient and robust star acquisition algorithm based on facet fitting is presented to improve the performance of star sensors. The location of star central pixels can be determined by searching extremum intensity pixels among the point spread function (PSF) of stars, which is well fitted by the cubic facet model. According to extremum theory, the second derivative operators are pre-calculated and the searching process can be completed using convolution operations thrice. Simultaneously, cluster formation is also a time consuming routine, which is accomplished using specific maximum and minimum threshold to speed up it. A variety of experiments are carried out to validate the performance of proposed algorithm, moreover, the performance evaluation index M is presented. The results clearly show that the proposed algorithm makes a great progress than the vector method in time expense and accuracy under intense noise conditions.© (2012) Trans Tech Publications, Switzerland.
Chen X.,Shaanxi Normal University |
Chen X.,Shaanxi Institute of Education |
Lu X.,Shaanxi Normal University |
Yang G.,Shaanxi Normal University
Catena | Year: 2012
The concentrations of Co, Cr, Cu, Mn, Ni, Pb, Zn, and V in urban topsoil samples collected from inside the Xi'an Second Ringroad, northwestern China were measured by X-ray fluorescence spectroscopy. Correlation coefficient analysis, factor analysis and cluster analysis were used to analyze the data and to identify the possible sources of these heavy metals. The results show that the mean concentrations of Co, Cr, Cu, Mn, Ni, Pb, Zn, and V in urban topsoil from Xi'an are 19.3, 81.1, 54.3, 671.5, 34.5, 59.7, 186.2, and 85.2mgkg -1 respectively, which are higher than the background values of Shaanxi soil. The mean concentrations of heavy metals in topsoil divided by the corresponding background values of Shaanxi soil increase in the order of Ni
Hu Z.,Shaanxi Institute of Education
Advances in Intelligent and Soft Computing | Year: 2011
The quality piano curriculum has been developed in many universities and colleges in China since its construction in 2006. I found some problems in many-year practical activities and thought it through, and studied the innovation mode of the quality piano curriculum on the basis of the status analysis on the quality piano curriculum of the senior normal universities and colleges to think that the passionate teaching is required for the quality piano curriculum and the modern media is necessary for constructing the piano teaching. So I put forward some viewpoints for how to innovate and construct the quality piano curriculum. © 2011 Springer-Verlag Berlin Heidelberg.
Li G.,Shaanxi Institute of Education |
Li G.,University of Chinese Academy of Sciences
Guangxue Jishu/Optical Technique | Year: 2011
A novel centroid algorithm is proposed to acquire better stars centroid performance in star image based on Gaussian point spread function (PSF). As photons incident on pixels of stars presents the near Gaussian distribution, therefore, the centroid locations in x and y axis are calculated respectively utilizing the pixel intensity ratio and expand the Gaussian PSF to be polynomials with respect to the centroid location. The statistic of angular separation error between star pairs is used to indirectly verify the proposed algorithm. The result clearly shows that the centroid accuracy achieves 1/33 of a pixel and improves about 2 times than the moment method, which indicates the proposed algorithm is effective and convenient. Furthermore, the relation between the centroid position and the attitude accuracy is analyzed. The test result shows that the proposed centroid algorithm can improve the attitude accuracy of the camera significantly.
Wang Q.,Shaanxi Institute of Education
Wuli Xuebao/Acta Physica Sinica | Year: 2010
Polycrystalline Bi0.5Ca0.5 Mn1-xCoxO3 (0≤x≤0.12) samples are synthesized by using the solid-state reaction. The effects of Co-doping on charge order of Bi0.5Ca0.5MnO3 are studied. The results show that Co doping leads to the melting of the charge order and the enhancement of the ferromagnetic correlation. For x≥0.08, the charge order transition is completely suppressed; however, there are still remaining antiferromagnetic domains inside the system. The phase separation or the coexistence of the charge order and ferromagnetic phase induced by Co-doping plays an important role in the low temperature properties for the system. Moreover, unlike in the case of rare-earth manganites, Co is more efficient to suppress charge order of Bi0.5Ca0.5MnO3 than Cr. © 2010 Chin. Phys. Soc.
Yang J.,Polytechnic University of Mozambique |
Chen J.,Shaanxi Institute of Education
Separation Science and Technology | Year: 2011
Silver-doped methyl-modified silica membranes (Ag/M-SiO2) have been prepared using the sol-gel method by adding AgNO3 solution to a methyl-modified silica sol. The influence of silver-doping on the physical and chemical structures, thermal stability of CH3 groups, and gas permeation performance for the silica membranes were investigated. The metallic silver results from the reduction of AgNO3 which can be completely transformed after calcined above 200° C. The Si CH3 vibrational bands disappear completely when the calcination temperature is increased to 600° C, which mineralized when the calcination temperature is further increased to 750° C. The doping of silver nanoparticles has nearly no influence on the chemical structure of the methyl-modified silica materials and the thermal stability of CH3 groups, but can make the mean pore size, total pore volume, H2 permeability, and H2/CO2 selectivities of the silica membranes increase. When operated at 200° C and a pressure difference of 0.35 MPa, the H2 permeance and H2/CO2 selectivity of Ag/M-SiO2 membrane with the AgNO3/ tetraethylorthosilicate molar ratio of 0.08 is 8.99 10 6 mol m 2 Pa 1 s1 and 10.22, respectively. After hydrothermal treatment and regeneration, the Ag/M-SiO2 membranes show a smaller change in gas permeances and H2/CO2 permselectivities than the methyl-modified silica membranes without silver-doping. © Taylor & Francis Group, LLC.
He M.,Shaanxi Normal University |
Wang Y.,Northwest University, China |
Hua W.,Shaanxi Institute of Education |
Zhang Y.,Shaanxi Normal University |
Wang Z.,Shaanxi Normal University
PLoS ONE | Year: 2012
Background: Hypericum perforatum L. (St. John's wort) is a medicinal plant with pharmacological properties that are antidepressant, anti-inflammatory, antiviral, anti-cancer, and antibacterial. Its major active metabolites are hypericins, hyperforins, and melatonin. However, little genetic information is available for this species, especially that concerning the biosynthetic pathways for active ingredients. Methodology/Principal Findings: Using de novo transcriptome analysis, we obtained 59,184 unigenes covering the entire life cycle of these plants. In all, 40,813 unigenes (68.86%) were annotated and 2,359 were assigned to secondary metabolic pathways. Among them, 260 unigenes are involved in the production of hypericin, hyperforin, and melatonin. Another 2,291 unigenes are classified as potential Type III polyketide synthase. Our BlastX search against the AGRIS database reveals 1,772 unigenes that are homologous to 47 known Arabidopsis transcription factor families. Further analysis shows that 10.61% (6,277) of these unigenes contain 7,643 SSRs. Conclusion: We have identified a set of putative genes involved in several secondary metabolism pathways, especially those related to the synthesis of its active ingredients. Our results will serve as an important platform for public information about gene expression, genomics, and functional genomics in H. perforatum. © 2012 He et al.
Ping L.,Shaanxi Institute of Education
Proceedings - 3rd International Conference on Multimedia Information Networking and Security, MINES 2011 | Year: 2011
This paper presented a novel gait recognition approach based on Haar wavelet and fused Hidden Markov Models. It solves the problem that key points in each region represent gait feature insufficiently. Firstly, images from video sequences are converted into binary silhouette. Haar wavelet transform is employed to obtain key points for distinct features, and the key points are analyzed. Two sub images are utilized to represent gait features in each silhouette, and employ Principal Component Analysis to reduce its dimensionalities. Finally, fused Hidden Markov Models are employed to train and test, and it is helpful in analyzing features. Consequently, we can not only simplify the process, but also improve the recognition accuracy. © 2011 IEEE.
Fang W.,Shaanxi Institute of Education |
Gai Z.,Xi'an Technological University
Applied Spectroscopy | Year: 2011
The basic principles and the application of hydride-generation multichannel atomic fluorescence spectrometry (HG-MC-AFS) in soil analysis are described. It is generally understood that only one or two elements can be simultaneously detected by commonly used one- or two-channel HG-AFS. In this work, a new sample-sensitive and effective method for the analysis of arsenic, bismuth, tellurium, and selenium in soil samples by simultaneous detection using HG-MC-AFS was developed. The method detection limits for arsenic, bismuth, tellurium, and selenium are 0.19 μg/g, 0.10 μg/g, 0.11 μg/g, and 0.08 μg/g, respectively. This method was successfully applied to the simultaneous determination of arsenic, bismuth, tellurium, and selenium in soil samples. © 2011 Society for Applied Spectroscopy.
Wang F.,Shaanxi Institute of Education |
Li Z.,Institute for Hygiene of Ordnance Industry |
Qiao B.,Institute for Hygiene of Ordnance Industry
Journal of X-Ray Science and Technology | Year: 2011
A rapid method for the analysis of iron concentrates by gel sample preparation and X-ray fluorescence (XRF) spectrometry detection was developed. The solution digested by aqua regia was mixed with agarose, and then agarose was dissolved in the boiling solution and the mixture became quasi-solid gel at ambient temperature. The quasi-solid gel was detected by XRF. Analytical characteristics of the methods used were compared, and their reliability were tested against several certified reference materials of iron concentrates. The relative standard deviation was less than 0.3%. © 2011-V IOS Press and the authors. All rights reserved.