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Search Results: 1 - 10 of 76267 matches for " Zhao Lu-Bing "
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Effects of V/III ratio on species diffusion anisotropy in the MOCVD growth of non-polar a-plane GaN films

Zhao Lu-Bing,Yu Tong-Jun,Wu Jie-Jun,Yang Zhi-Jian,Zhang Guo-Yi,

中国物理 B , 2010,
Abstract: Non-polar a-plane (11\bar 20) GaN films have been grown on r-plane (1\bar 102) sapphire substrates by metal organic chemical vapour deposition. The influences of V/III ratio on the species diffusion anisotropy of a-plane GaN films were investigated by scanning electron microscopy, cathodoluminescence and high-resolution x-ray diffraction measurements. The anisotropy of a-plane GaN films may result from the different migration length of adatoms along two in-plane directions. V/III ratio has an effect on the growth rates of different facets and crystal quality. The stripe feature morphology was obviously observed in the film with a high V/III ratio because of the slow growth rate along the 1\bar 100] direction. When the V/III ratio increased from 1000 to 6000, the in-plane crystal quality anisotropy was decreased due to the weakened predominance in migration length of gallium adatoms.
Optical Defect in GaN-Based Laser Diodes Detected by Cathodoluminescence

ZHAO Lu-Bing,WU Jie-Jun,XU Ke,BAO Kui,YANG Zhi-Jian,PAN Yao-Bo,HU Xiao-Dong,ZHANG Guo-Yi,

中国物理快报 , 2008,
Abstract: GaN-based laser diodes (LDs) with 399nm wavelength are grown on sapphire substrates by metal organic chemical vapour deposition (MOCVD). Electroluminescence spectra of the fabricated LDs show that the LDs from some grown wafers failed to emit laser. The SEM and XRD results show the similar surface morphology and interface qualities of multi quantum wells (MQWs) and super-lattices between LDs that succeed and fail to emit laser. However, the cathodoluminescence (CL) measurements reveal a kind of optical defect rather than structural defect in un-emitted LDs. Further depth-dependent CL imaging observation indicates that such optical defects originate from the MQWs to the surface of LDs as a non-irradiative recombination centre that should cause the failure of laser emitting of LDs.

ZHANG Li-hong LEI Yi-qing,YUAN Lu-bing,

高分子学报 , 1990,
Abstract: Kinetic studies of polyesterification of ethylene glycol and dibasic acid (maleic acid and phthalic anhydride) were investigated. The kinetic data obtained from reactions are agree with the corresponding equations proposed by Lin, but when the concentration of ethylene glycol is higher, the kinetic processes do not fit with Lin's view. In all reactions, two reactive rate constants are existed obviously.
A Data Flow Behavior Constraints Model for Branch Decisionmaking Variables
Lu Yan,Wang Dan,Zhao Wen Bing
International Journal of Wireless and Microwave Technologies , 2012, DOI: 10.5815/ijwmt.2012.03.06
Abstract: In order to detect the attacks to decision-making variable, this paper presents a data flow behavior constraint model for branch decision-making variables. Our model is expanded from the common control flow model, itemphasizes on the analysis and verification about the data flow for decision-making variables, so that to ensure the branch statement can execute correctly and can also detect the attack to branch decision-making variableeasily. The constraints of our model include the collection of variables, the statements that the decision-making variables are dependent on and the data flow constraint with the use-def relation of these variables. Our experimental results indicate that it is effective in detecting the attacks to branch decision-making variables as well as the attacks to control-data.
Numerical Simulation of a Landfall Typhoon Using a Bogus Data Assimilation Scheme
LU Bing,WANG Bin,ZHAO Ying,
LU Bing

大气和海洋科学快报 , 2011,
Abstract: A typhoon bogus data assimilation scheme (BDA) using dimension-reduced projection four-dimensional variational data assimilation (DRP-4-DVar), called DRP-BDA for short, is built in the Advanced Regional Eta Model (AREM). As an adjoint-free approach, DRPBDA saves time, and only several minutes are taken for the full BDA process. To evaluate its performance, the DRP-BDA is applied to a case study on a landfall typhoon, Fengshen (2008), from the Northwestern Pacific Ocean to Guangdong province, in which the bogus sea level pressure (SLP) is assimilated as a kind of observation. The results show that a more realistic typhoon with correct center position, stronger warm core vortex, and more reasonable wind fields is reproduced in the analyzed initial condition through the new approach. Compared with the control run (CTRL) initialized with NCEP Final (FNL) Global Tropospheric Analyses, the DRP-BDA leads to an evidently positive impact on typhoon track forecasting and a small positive impact on typhoon intensity forecasting. Furthermore, the forecast landfall time conforms to the observed landfall time, and the forecast track error at the 36th hour is 32 km, which is much less than that of the CTRL (450 km).
Photocatalytical Properties and Theoretical Analysis of N, Cd-Codoped TiO2 Synthesized by Thermal Decomposition Method
Hongtao Gao,Bing Lu,Fangfang Liu,Yuanyuan Liu,Xian Zhao
International Journal of Photoenergy , 2012, DOI: 10.1155/2012/453018
Abstract: N, Cd-codoped TiO2 have been synthesized by thermal decomposition method. The products were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), UV-visible diffuse reflectance spectra (DRS), X-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller (BET) specific surface area analysis, respectively. The products represented good performance in photocatalytic degradation of methyl orange. The effect of the incorporation of N and Cd on electronic structure and optical properties of TiO2 was studied by first-principle calculations on the basis of density functional theory (DFT). The impurity states, introduced by N 2p or Cd 5d, lied between the valence band and the conduction band. Due to dopants, the band gap of N, Cd-codoped TiO2 became narrow. The electronic transition from the valence band to conduction band became easy, which could account for the observed photocatalytic performance of N, Cd-codoped TiO2. The theoretical analysis might provide a probable reference for the experimentally element-doped TiO2 synthesis.
Sub-Entire-Domain Basis Function Method for Irrectangular Periodic Structures
Wei Bing Lu;Qian Yi Zhao;Tie-Jun Cui
PIER B , 2008, DOI: 10.2528/PIERB08020401
Abstract: The Sub-Entire-Domain (SED) basis function method has been applied to solve electromagnetic problems of irrectangular periodic structures with finite sizes efficiently. Three typical irrectangular periodic structures such as parallelogrammic periodic structures, triangular periodic structures, and trapeziform periodic structures are investigated using the SED basis function method. Just as the SED basis functions for rectangular periodic structures, the new SED basis functions for irrectangular periodic structures are defined on the support of each single cell, and the corresponding dummy cells are introduced to obtain the new SED basis functions. Using the proposed SED basis function method, the original large-scale problem is decomposed into two small-size problems. One is the determination of new SED basis functions, and the other is to solve the whole problem using MoM and SED basis functions. Numerical examples are given to prove the validity and efficiency of the new method.
Genetic diversity of Mycobacterium tuberculosis isolates from Beijing, China assessed by Spoligotyping, LSPs and VNTR profiles
Lu Bing,Zhao Ping,Liu Binbin,Dong Haiyan
BMC Infectious Diseases , 2012, DOI: 10.1186/1471-2334-12-372
Abstract: Background Tuberculosis is one of the most infectious diseases in the world. Molecular typing methods such as spoligotyping, and VNTR (variable number tandem repeats), IS6110 in the NTF region and LSP (large sequence polymorphisms) analysis are generally useful tools for the resolution of various issues related to the classical epidemiology of Mycobacterium tuberculosis (M. tuberculosis). Methods To determine the transmission characteristics of M. tuberculosis strains isolated in Beijing, China, and their genetic relationships, especially those among Beijing family strains, 260 M. tuberculosis strains isolated from patients presenting pulmonary tuberculosis were analyzed by spoligotyping, and by examining 22 VNTR loci and the presence/absence of IS6110 in the NTF region, RD105 and RD181. Results 81% (211 strains) of the isolates studied were Beijing family strains, 174 (82.5%) of which were identified as modern Beijing strains based on the presence of IS6110 upstream of the NTF region. RD181 was intact in 9 of the other 37 (17.5%) ancestral Beijing strains. The percentage of Beijing family strains in this study was consistent with previous reports. There are many differences, however, in allele diversity among VNTR loci between reports on strains from different areas. Conclusions The Beijing family is the most prevalent genotype in Beijing city and the predominance of Beijing family strains has not altered in almost twenty years. Differences in the alleles and discrimination ability of VNTR loci between different regions is likely due to population differences in the regions where these M. tuberculosis strains were isolated or to differences in sampling times.
Multidimensionally-constrained relativistic Hartree-Bogoliubov study of nuclear spontaneous fission
Jie Zhao,Bing-Nan Lu,Tamara Niksic,Dario Vretenar
Physics , 2015,
Abstract: Recent microscopic studies, based on the theoretical framework of nuclear energy density functionals, have analyzed dynamic (least action) and static (minimum energy) fission paths, and it has been shown that in addition to the important role played by nonaxial and/or octupole collective degrees of freedom, fission paths crucially depend on the approximations adopted in calculating the collective inertia. The dynamics of spontaneous fission of $^{264}$Fm and $^{250}$Fm is explored. The fission paths, action integrals and the corresponding half-lives predicted by the functionals PC-PK1 and DD-PC1 are compared and, in the case of $^{264}$Fm, discussed in relation with recent results obtained using the HFB model based on the Skyrme functional SkM$^*$ and a density dependent mixed pairing interaction. Deformation energy surfaces, collective potentials, and perturbative and nonperturbative cranking collective inertia tensors are calculated using the multidimensionally-constrained relativistic Hartree-Bogoliubov (MDC-RHB) model, with the energy density functionals PC-PK1 and DD-PC1. Pairing correlations are treated in the Bogoliubov approximation using a separable pairing force of finite range. The least-action principle is employed to determine dynamic spontaneous fission paths.
Potential energy surfaces of actinide and transfermium nuclei from multi-dimensional constraint covariant density functional theories
Lu Bing-Nan,Zhao Jie,Zhao En-Guang,Zhou Shan-Gui
EPJ Web of Conferences , 2012, DOI: 10.1051/epjconf/20123805003
Abstract: Multi-dimensional constrained covariant density functional theories were developed recently. In these theories, all shape degrees of freedom βλμ deformations with even μ are allowed, e.g., β20, β22, β30, β32, β40, β42, β44, and so on and the CDFT functional can be one of the following four forms: the meson exchange or point-coupling nucleon interactions combined with the non-linear or density-dependent couplings. In this contribution, some applications of these theories are presented. The potential energy surfaces of actinide nuclei in the (β20, β22, β30) deformation space are investigated. It is found that besides the octupole deformation, the triaxiality also plays an important role upon the second fission barriers. The non-axial reflection-asymmetric β32 shape in some transfermium nuclei with N = 150, namely 246Cm, 248Cf, 250Fm, and 252No are studied.
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