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Search Results: 1 - 10 of 104102 matches for " Xiaoqing Zhang "
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Enhanced Nonlinear Absorption Performance of Reduced Graphene Oxide Nanohybrid Covalently Functionalized by Porphyrin via 1,3-Dipolar Cycloaddition  [PDF]
Nan Zhang, Xiaoqing Cong
Materials Sciences and Applications (MSA) , 2018, DOI: 10.4236/msa.2018.912070
Abstract: Porphyrin-functionalized reduced graphene oxide (RGO-TPP) was prepared by 1,3-dipolar cycloaddition reaction and characterized by Fourier transform infrared spectroscopy, Raman, ultraviolet/visible absorption, fluorescence, and transmission electron microscopy. At the same level of linear transmittance, RGO-TPP exhibited more enhanced optical nonlinearities than RGO and the pristineporphyrin, implying a remarkable accumulation effect as a result of the covalent link between RGO and porphyrin. The role of energy/electron transfer in the optical nonlinearities of RGO-TPP was investigated by fluorescence and Raman spectroscopy. All the results displayed that RGO can be covalently functionalized with porphyrins by the proposed approach.
An Efficient Algorithm for Transient Calculation of the Electric Networks Including Magnetizing Branches
Xiaoqing Zhang
Mathematical Problems in Engineering , 2011, DOI: 10.1155/2011/479626
Abstract: A simplified model of magnetic saturation characteristics is proposed in this paper for transient calculation of the electric networks including magnetizing branches. The model represents the magnetic saturation characteristics by the continuous function instead of the piecewise linear approximation. Based on the proposed model, an efficient transient algorithm is developed. The nonlinear differential equations describing the transient behavior of the magnetizing branches are solved by the semiexplicit Runge-Kutta method, in which noniterative computations are involved. The transient calculation for the remaining linear network is performed in terms of the solution to the magnetizing branches. A comparison is made between calculated and experimental results to confirm the validity of the algorithm.
Integrated Compact Circular Polarization Annular Ring Slot Antenna Design for RFID Reader
Junlin Zhang;Xiaoqing Yang
PIER Letters , 2013,
Abstract: An integrated compact circular-polarized annular ring slot antenna is proposed in this paper. It consists of an annular ring slot radiator and a hybrid patch coupler. The hybrid patch coupler is integrated with the annular ring slot antenna to radiate the circular-polarized wave, while size of the antenna remains the same. Both the impedance bandwidth and axial ratio bandwidth of the proposed design almost cover the entire UHF band of RFID system and it has the features of easy fabrication and low cost. To verify the proposed design, a prototype is fabricated. Measured results agree well with the simulated results.
Association between 9p21 Genomic Markers and Ischemic Stroke Risk: Evidence Based on 21 Studies
Xiaoqing Ni, Jiawei Zhang
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0090255
Abstract: Epidemiological studies indicate a genetic contribution to ischemic stroke risk, but specific genetic variants remain unknown. Recently independent studies reported an association between coronary heart disease and single-nucleotide polymorphisms (SNPs) located at chromosome 9p21 (rs10757278 and proxy SNPs). Given that stroke is a common complication after myocardial infarction, several validation studies have been conducted among various ethnic populations to investigate if the same loci was associated with ischemic stroke (IS), but the results have been inconsistent. To investigate this inconsistency and derive a more precise estimation of the relationship, a meta-analysis of 34,128 cases and 153,428 controls from 21 studies was performed. Potential sources of heterogeneity including ethnicity, sample size, control source and ischemic stroke subtypes were also assessed. Overall, the summary odds ratio of IS was 1.11 (95% CI: 1.07–1.15, P<10?5) for rs10757278. In the subgroup analysis by ethnicity, significantly increased risks were found in East Asians (3188 cases and 4503 controls; OR = 1.14, 95% CI: 1.07–1.21, P<10?5) and Caucasians (30505 cases and 145153controls; OR = 1.08, 95% CI: 1.04–1.12, P<10?5) for the polymorphism; while no significant associations were found among African Americans (435 cases and 3772 controls; OR = 0.97, 95% CI: 0.63–1.51, P = 0.90) in all genetic models. In the subgroup analyses by IS subtypes, significant association was detected only in large vessel stroke group, while no significant associations among small vessel or cardioembolic stroke. When stratified by sample size, and control source, significantly increased risks were found for the polymorphism in all genetic models. This meta-analysis provides accurate and comprehensive estimates of the association of genetic variant at chromosome 9p21 and IS, but these associations vary in different ethnic populations.
An Identified Study on the Active Network of a Thermoacoustic Regenerator  [PDF]
Guozhong Ding, Feng Wu, Gang Zhou, Xiaoqing Zhang, Jiuyang Yu
Engineering (ENG) , 2009, DOI: 10.4236/eng.2009.11003
Abstract: An active thermo-acoustic network model of regenerator which is a key component to accomplish the con-version between thermal-and acoustic power in thermo-acoustic system has been established in this paper. The experiment was carried out to quantify the network. A method called least square is employed in order to identify the H matrix describing the system. The results obtained here show that the active thermo-acoustic network can reliably depict the characteristics of a thermo-acoustic system.
The Relationship between Professional Identity and Career Maturity among Pre-Service Kindergarten Teachers: The Mediating Effect of Learning Engagement  [PDF]
Liying Zhang, Meirong Chen, Xiaoqing Zeng, Xinqiang Wang
Open Journal of Social Sciences (JSS) , 2018, DOI: 10.4236/jss.2018.66016
Abstract: Objective: To investigate the mediating role of leaning engagement in the relationship between professional identity and career maturity. Methods: 711 pre-service kindergarten teachers completed the Professional Identification Scale, the College Students’ Career Maturity Questionnaire and the Utrecht Work Engagement Scale-student. Results: 1) There are significant difference in professional identity and career maturity on grades, different level of parents’ education and whether part-time work. 2) Professional identity, career maturity, and learning engagement were significantly correlated with each other. 3) Career maturity partially mediated the relationship between professional identity and learning engagement. Conclusion: Professional identity directly influences learning engagement, and also influences learning engagement through the partial mediating effects of career maturity.
Abundant Lump Solutions and Interaction Phenomena to the Kadomtsev-Petviashvili-Benjamin-Bona-Mahony Equation  [PDF]
Jianqing Lü, Sudao Bilige, Xiaoqing Gao, Yuexing Bai, Runfa Zhang
Journal of Applied Mathematics and Physics (JAMP) , 2018, DOI: 10.4236/jamp.2018.68148
Abstract:
In this paper, we obtained a kind of lump solutions of the Kadomtsev-Petviashvili-Benjamin-Bona-Mahony (KP-BBM) equation with the assistance of Mathematica. Some contour plots with different determinant values are sequentially made to show that the corresponding lump solutions tend to zero when x2+y2→∞. Particularly, lump solutions with specific values of the include parameters are plotted, as illustrative examples. Finally, a combination of stripe soliton and lump soliton is discussed to the KP-BBM equation, in which such a solution presents two different interesting phenomena: lump-kink and lump-soliton. Simultaneously, breather rational soliton solutions are displayed.
Heavy Metals Contamination in Greenhouse Soils and Vegetables in Guanzhong, China  [PDF]
Ling Liu, Jinyin Lu, Zhenwen Zhang, Hai Zheng, Xiaoqing Gao, Wei Zhang
Journal of Encapsulation and Adsorption Sciences (JEAS) , 2014, DOI: 10.4236/jeas.2014.43009
Abstract: This study used a flame atomic absorption spectrometer (FAAS) and atomic fluorescence spec-trophotometer (AFS) to detect the concentrations of chromium (Cr), cadmium (Cd), lead (Pb), hy-drargyrum (Hg) and arsenic (As) in soils and three genotypes of vegetables in greenhouse, as well as analyzed the physical and chemical properties of soils, including soil pH, soil organic matter (OM), basic nutrients, electrical conductivity (EC) and cation exchange capacity (CEC) in Guan- zhong areas, Shaanxi province, China. The results showed that comparing to subsoil, the sampled topsoil is enriched in Cr, Cd, Pb, As and Hg. Cd (0.83 - 3.17 mg·kg-1) and Hg (0.40 - 1.44 mg·kg-1) are exceeding the limited value stated in “the 2006 Greenhouse Vegetable Producing Environmental Quality Evaluation Standards” of 0.40 mg·kg-1 and 0.35 mg·kg-1 respectively. However, Nanzhuang greenhouse soil is within the limits. The heavy metal pollution index (HPI) of soil in Sanyuan (8.10) is the highest and in Dongzhang (4.23) is the lowest. The contents of Pb (0.201 - 0.376 mg·kg-1) were exceeding the limited value (0.20 mg·kg
Genesis of Carlin-type gold deposits in southwestern Guizhou Province, China
Xiaoqing Zhu,Zhengen Zhang,Zechun Jiang
Chinese Science Bulletin , 1999, DOI: 10.1007/BF02977890
Abstract: A solution containing nanometer-sized pure gold particles was prepared with the hydrolysisreduction method. As observed under the electron microscope, the gold particles were as large as 2–20 nm in size. Different kinds of mineral and rock were put into the solution and the experimental result showed that the nanometer-sized gold particles are obviously adsorbed on sulfide minerals, native copper and carbonaceous rocks. This experimental result is consistent with the actual geological observation. On this basis a better explanation is presented of the genesis of the Carlin-type gold deposits.
Discussion of the Patron Management Pattern and Patron Service Pattern in the Digital Library
论数字图书馆的用户管理与用户服务模式

Zhang Xiaoqing,
张晓青

现代图书情报技术 , 2003,
Abstract: The article analyses and discusses the current patron management manners and patron service state in the digital library, presents the new patron management pattern and patron service pattern. The paper thinks that a reasonable patron management pattern is the combination of the IP authentication plus firewall segregation manner and the user authentication plus access authorization manner, and the basic patron service patter is the combination of the integrated information service and the personalized customization service in the digital library.
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