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Search Results: 1 - 10 of 120022 matches for " Yongqin Wang "
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Unified Representation of Quantum Mechanics on One-dimensional Harmonic Oscillator
Yongqin Wang
Physics , 2013,
Abstract: A quantum state corresponds to a specific wave function. We adopt a new mathematical method [1] to improve Dirac's ladder operator method. A set of orthonormal wave functions will be used to associate the operator with the square matrix corresponding to it. These allow us to determine the matrix elements by using the operator relations without having to know the specific wave functions. As a result, we can get the direct results of matrix mechanics and wave mechanics on one-dimensional Harmonic oscillator and their descriptions will be also unified.
Unified Description of Matrix Mechanics and Wave Mechanics on Hydrogen Atom
Yongqin Wang,Lifeng Kang
Physics , 2011,
Abstract: A new mathematical method is established to represent the operator, wave functions and square matrix in the same representation. We can obtain the specific square matrices corresponding to the angular momentum and Runge-Lenz vector operators with invoking assistance from the operator relations and the orthonormal wave functions. Furthermore, the first-order differential equations will be given to deduce the specific wave functions without using the solution of the second order Schrodinger equation. As a result, we will unify the descriptions of the matrix mechanics and the wave mechanics on hydrogen atom. By using matrix transformations, we will also deduce the specific matrix representations of the operators in the SO (4,2) group.
Well-posedness of the IBVP for 2-D Euler Equations with Damping
Yongqin Liu,Weike Wang
Mathematics , 2008,
Abstract: In this paper we focus on the initial-boundary value problem of the 2-D isentropic Euler equations with damping. We prove the global-in-time existence of classical solution to the initial-boundary value problem by the method of energy estimates.
Room Temperature Ferromagnetism of (Mn,Fe) Codoped ZnO Nanowires Synthesized by Chemical Vapor Deposition
Yongqin Chang,Pengwei Wang,Qingling Sun,Yongwei Wang,Yi Long
Journal of Nanomaterials , 2011, DOI: 10.1155/2011/367156
Abstract: (Mn,Fe) codoped ZnO nanowires were synthesized on silicon substrates in situ using a chemical vapor deposition method. The structure and property of the products were investigated by X-ray, electron microscopy, Raman, photoluminescence, and superconducting quantum interference device magnetometer. The doped nanowires are of pure wurtzite phase with single crystalline, and the elements distribute homogeneously in the doped nanowires. Photoluminescence spectrum of the doped nanowires is dominated by a deep-level emission with a negligible near-band-edge emission. The magnetic hysteresis curve with a coercive field of 35 Oe is clearly observed at 300?K, resulting from room-temperature ferromagnetic ordering in the (Mn,Fe) codoped ZnO nanowires, which has great potential applications for spintronics devices. 1. Introduction Diluted magnetic semiconductors (DMSs) have stimulated great interest in recent years due to their potential applications in spintronics devices, where the spin degree of freedom of the electron is utilized in addition to its carrier concentration [1–3]. A promising technique is to use DMS to inject spin-polarized carriers into nonmagnetic semiconductor, and it is very important that the DMS materials have room temperature ferromagnetic property for the practical applications. ZnO doped with transition metals is one of the most promising DMS candidates, as it was predicted to be ferromagnetic above room temperature [1, 4], and some room temperature ferromagnetic materials have been successfully synthesized by several groups [5–7]. To integrate the ZnO-based DMSs into present electronics, it is reasoned that the combination of low dimensionality and room-temperature ferromagnetism in diluted magnetic oxides would generate new functional nanomaterials useful for future spintronics nanodevices. Some efforts have been focused on this kind of material, such as the fabrication of Mn-doped ZnO nanorods arrays [8] and Co-doped ZnO nanoneedle arrays [9]. Recently, several codoped DMS materials have been reported with the expectation that codoping can lead to remarkable improvement in the properties of DMS [10, 11]. Chakrabarti et al. reported that the saturation magnetic field can be enhanced by doping addition 2% Fe in the Mn-doped ZnO system [12]. Codoped Mn and Fe in ZnO nanostructures may contribute the local magnetic moments and enhancement of the charge carrier density. To the best of our knowledge, there was no research presented on Mn- and Fe-codoped ZnO nanostructures. In this letter, magnetization above room temperature has been
On the Geometric Blow-Up Mechanism to Scalar Conservation Laws  [PDF]
Shikuan Mao, Yongqin Liu
International Journal of Modern Nonlinear Theory and Application (IJMNTA) , 2013, DOI: 10.4236/ijmnta.2013.23021
Abstract:

The focus of this article is on the geometric mechanism for the blow-up of solutions to the initial value problem for scalar conservation laws. We prove that the sufficient and necessary condition of blow-up is the formation of characteristics envelope. Whether the solution blows up or not relates to the topology structure of a set dominated by initial data. At last we take Burger’s equation as an example to verify our main theorem.

Pointwise Estimates for Solutions to a System of Radiating Gas  [PDF]
Shikuan Mao, Yongqin Liu
International Journal of Modern Nonlinear Theory and Application (IJMNTA) , 2013, DOI: 10.4236/ijmnta.2013.23026
Abstract:

In this paper we focus on the initial value problem of a hyperbolic-elliptic coupled system in multi-dimensional space of a radiating gas. By using the method of Green function combined with Fourier analysis, we obtain the pointwise decay estimates of solutions to the problem.

Review of Oil and Gas Development Life Cycle Project Management (LCPM)  [PDF]
Yongqin Yan, Haohan Liu
Engineering (ENG) , 2016, DOI: 10.4236/eng.2016.83009
Abstract: The effective implementation of the project management plays a core roll in avoiding bad project use effect and waste of funds, caused by asset management planning and design errors or equipment selection errors; meanwhile, it can effectively improve the operational efficiency of enterprise assets, lower operating costs and save resources. In June 1974, A. Gordon published a paper “3L Economics Concept” as the starting point, on the “Building and Quantity Surveying”, which is organized by the Royal Institution of Chartered Surveyors. In this paper, a review of domestic and foreign research, from 1974 to 2015, on the total life cycle management progress will be given, and then a comment on it will be established. After detailed investigation and analysis of related materials, we can draw a conclusion: the study of the oil and gas development project lifecycle management is just beginning now. Hence, building the whole life cycle planning index system in line with the characteristics of oil and gas development project is very necessary.
The Pointwise Estimates of Solutions for Semilinear Dissipative Wave Equation
Yongqin Liu
Mathematics , 2008,
Abstract: In this paper we focus on the global-in-time existence and the pointwise estimates of solutions to the initial value problem for the semilinear dissipative wave equation in multi-dimensions. By using the method of Green function combined with the energy estimates, we obtain the pointwise estimates of the solution.
Genetic Variants Associated with Myocardial Infarction and the Risk Factors in Chinese Population
Yongqin Wang, Lefeng Wang, Xin Liu, Yongzhi Zhang, Liping Yu, Fan Zhang, Lisheng Liu, Jun Cai, Xinchun Yang, Xingyu Wang
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0086332
Abstract: Background Recent genome-wide association (GWA) studies in Caucasians identified multiple single nucleotide polymorphisms (SNPs) associated with coronary artery disease (CAD). The associations of those SNPs with myocardial infarction (MI) have not been replicated in Asian populations. Among those previously identified SNPs, we selected nine (rs10953541, rs1122608, rs12190287, rs12413409, rs1412444, rs1746048, rs3798220, rs4977574, rs579459, in or near genes 7q22, LDLR, TCF21, CYP17A1, LIPA, CXCL12, LPA, CDKN2A, ABO, respectively) because of the relatively high minor allele frequencies in Chinese individuals and tested the associations of the SNPs with MI and MI related risk factors in Chinese population. Methods and Results We conducted a case–control association study on a cohort of 2365 MI patients and 2678 unrelated controls from the Chinese population. Genotyping of 9 SNPs were performed by the TaqMan Real Time PCR method. After age, sex, and BMI adjustment, we observed the SNPs rs12190287, rs12413409, rs1412444, rs1746048 and rs4977574, were significantly associated with MI in additive models and rs12190287, rs12413409, rs4977574 were significantly associated with phenotypes of MI at the same time. We also found three SNPs rs1122608, rs3798220 and rs579459 were significantly associated with risk factors of MI, although they had no association with MI in Chinese population. Conclusion Results of this study indicate that 5 SNPs were associated with MI and 3 SNPs were associated with associated with lipoprotein levels but not with MI in a Chinese population. The present study supports some CAD-related genes in Caucasian as important genes for MI in a Chinese population.
Lateral Oxidation in Vertical Cavity Surface Emitting Lasers
Liu Wenli,Hao Yongqin,Wang Yuxi,Jiang Xiaoguang,Feng Yuan,Li Haijun,Zhong Jingchang,
Liu Wenli
,Hao Yongqin,Wang Yuxi,Jiang Xiaoguang,Feng Yuan,Li Haijun,Zhong Jingchang

半导体学报 , 2006,
Abstract: 研究了垂直腔面发射激光器(VCSEL)的侧向氧化工艺及其特性.发现对于条形台面,氧化物生长遵循线性生长规律.但对于在VCSEL中采用的两种结构,氧化物的生长(温度高于435℃)表现为非线性生长行为.理论分析表明,台面结构的几何形状对高温下的氧化速率产生了影响.
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