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Search Results: 1 - 10 of 43481 matches for " Shan Zhao "
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A matched alternating direction implicit (ADI) method for solving the heat equation with interfaces
Shan Zhao
Mathematics , 2014,
Abstract: A novel Douglas alternating direction implicit (ADI) method is proposed in this work to solve a two-dimensional (2D) heat equation with interfaces. The ADI scheme is a powerful finite difference method for solving parabolic equations, due to its unconditional stability and high efficiency. However, it suffers from a serious accuracy reduction in space for interface problems with different materials and nonsmooth solutions. If the jumps in a function and its derivatives are known across the interface, rigorous ADI schemes have been successfully constructed in the literature based on the immersed interface method (IIM) so that the spatial accuracy can be restored. Nevertheless, the development of accurate and stable ADI methods for general parabolic interface problems with physical interface conditions that describe jumps of a function and its flux, remains unsolved. To overcome this difficulty, a novel tensor product decomposition is proposed in this paper to decouple 2D jump conditions into essentially one-dimensional (1D) ones. These 1D conditions can then be incorporated into the ADI central difference discretization, using the matched interface and boundary (MIB) technique. Fast algebraic solvers for perturbed tridiagonal systems are developed to maintain the computational efficiency. Stability analysis is conducted through eigenvalue spectrum analysis, which numerically demonstrates the unconditional stability of the proposed ADI method. The matched ADI scheme achieves the first order of accuracy in time and second order of accuracy in space in all tested parabolic interface problems with complex geometries and spatial-temporal dependent jump conditions.
Clinical observation of the curative effect of Qiangxin Mixture on congestive heart failure
CHEN Zhao-Shan
Zhong Xi Yi Jie He Xue Bao , 2003,
Abstract: Objective: To investigate the efficacy of Qiangxin Mixture in patients with congestive heart failure (CHF). Methods: Sixty cases of CHF were randomly divided into Qiangxin Mixture group (treatment group,n=30) and digoxin group (control group, n=30).The total clinical effective rate,integra of the symptoms of kidney deficiency, classification of functional capacity of the NewYork Heart Association (NYHA), and echocardiogram[ejection fraction (EF), cardiac output (CO), interventricular septal thickness (IVST), posterior wall thickness (PWT), left ventricular mass index (LVMI)] as well as the measurement of plasma endothelin, angiotensin II and atrial natriuretic peptide were observed in both groups. Results: The total clinical effective rate of Qiangxin Mixture group was 87%, and improvement was significantly observed in the Lee CHF score, classification of functional capacity of the NYHA, EF and CO(P<0.05,vs before treatment),but no significant improvement in digoxin group (P>0.05). The integra of the symptoms of kidney deficiency, the levels of plasma ET, Ang II and ANP decreased significantly (P<0.01) vs before treatment and digoxin group respectively). IVST,PWT and LVMI were also reduced significantly(P <0.01)vs before treatment;P<0.05 vs digoxin group). Conclusion: The Qiangxin Mixture is effective in enhencing cardiac contraction,improving hemodynamics in the short-term and rectifying some indexes in the long-term,so it could postpone the processes of CHF. This mechanism may be related to decreasing the stimulating factors (angiotensin, endothelin) which trigger the cardiac remodeling, delaying or reversing the cardiac remodeling.
Study of genes related with kidney deficiency syndrome
ZHAO Xiao-Shan
Zhong Xi Yi Jie He Xue Bao , 2003,
Abstract: ABSTRACT: Study of kidney deficiency syndrome may utilize the modern molecular biology technique, such as gene chip, representational difference analysis (RDA) and genes sequence analysis, to clone the different genes of kidney deficiency syndrome from single TCM syndrome type of the disease, to investigate the inner connection between the various phenotypes of kidney deficiency syndrome and their genes expression pattern and their function products, then to definite the related genes of kidney deficiency syndrome. The research method may also be used for the study of other TCM syndrome types.
Current Language Attitudes of Mainland Chinese University Students
Meihua Liu,Shan Zhao
Journal of Language Teaching and Research , 2011, DOI: 10.4304/jltr.2.5.963-968
Abstract: This paper reports on an investigation of Chinese university EFL learners’ attitudes towards English and Chinese in relation to their motivation to learn the language and awareness of their ethnic identity. 302 university students answered a 22-item Language Attitudes Questionnaire and 112 of them answered four open-ended questions. Analyses of the data reveal that the participants held positive attitudes towards English, were motivated to learn the language, and valued their association with English-speaking culture and people, meanwhile considering their native language superior to English. Thus the paper concludes that the students had a sound sense of Chinese identity with an appreciation of the value of the English language.
Unconditionally stable time splitting methods for the electrostatic analysis of solvated biomolecules
Leighton Wilson,Shan Zhao
Quantitative Biology , 2014,
Abstract: This work introduces novel unconditionally stable operator splitting methods for solving the time dependent nonlinear Poisson-Boltzmann (NPB) equation for the electrostatic analysis of solvated biomolecules. In a pseudo-transient continuation solution of the NPB equation, a long time integration is needed to reach the steady state. This calls for time stepping schemes that are stable and accurate for large time increments. The existing alternating direction implicit (ADI) methods for the NPB equation are known to be conditionally stable, although being fully implicit. To overcome this difficulty, we propose several new operator splitting schemes, in both multiplicative and additive styles, including locally one-dimensional (LOD) schemes and additive operator splitting (AOS) schemes. The proposed schemes become much more stable than the ADI methods, and some of them are indeed unconditionally stable in dealing with solvated proteins with source singularities and non-smooth solutions. Numerically, the orders of convergence in both space and time are found to be one. Nevertheless, the precision in calculating the electrostatic free energy is low, unless a small time increment is used. Further accuracy improvements are thus considered. After acceleration, the optimized LOD method can produce a reliable energy estimate by integrating for a small and fixed number of time steps. Since one only needs to solve a tridiagonal linear system in each independent one dimensional process, the overall computation is very efficient. The unconditionally stable LOD method scales linearly with respect to the number of atoms in the protein studies, and is over 20 times faster than the conditionally stable ADI methods.
The Technical Analysis on Upgrade and Coupling of Low-Quality Coal  [PDF]
Bin Zhao, Qiang Yao, Shan Lu, Qinggong Wang, Junfu Lv
Energy and Power Engineering (EPE) , 2014, DOI: 10.4236/epe.2014.613039
Abstract: Experimental study was conducted with regard to upgrading low-quality coal by low temperature pyrolysis technology and fluidization classification technology, which laid the theoretical foundation for research and development of low-quality coal upgrading process. Firstly, a pyrolysis pilot experiment of long-flame coal was performed and the optimum pyrolysis conditions were found. When the final pyrolysis temperature was 450?C and the residence time was 10 minutes, the content of semicoke volatile dry ash-free was about 22.89% and the content of semicoke ash was about 16.1%. More than 5% of the ash needs to be removed before entering the pyrolysis fluidized bed. Thus, classification tests were carried out to pick out the coal particles with the target size of 500 μm, using a gas-solid fluidized bed coal picker. It was found that the separating effect of coal particles was the most satisfactory when the inlet velocity at the bottom was 3.27 m/s. The percentage of particles with diameters less than 500 μm was as low as 28.7% in the coarse samples. Based on the test results, a novel process of low-quality coal upgrade and coupling was proposed, which realized the sorting, grading, drying and pyrolysis of low-quality coal through the multi-stage fluidized bed integrated process.
Hybrid PMM-MoM Method for the Analysis of Finite Periodic Structures  [PDF]
Shan Zhao, Naiqian Zhang, Dong Li, Jianxun Su
Open Journal of Applied Sciences (OJAppS) , 2012, DOI: 10.4236/ojapps.2012.24B040
Abstract: In this paper, a hybrid method (hybrid PMM-MoM method) is presented for the effective and accurate analysis of finite periodic structures. This method divides a finite periodic structure into two parts. The inner part of an approximate infinite periodic structure is analyzed by periodic method of moment (PMM); the outer part is then analyzed by method of moments (MoM). For the finite periodic structures, the accuracy of the new method is much better than that of the pure PMM, and is almost the same as that of pure MoM. Because pure PMM uses the periodic boundary conditions, it takes much less memory resources and computation time. For hybrid PMM-MoM method, because the inner part is calculated by PMM, the calculation work concentrates on the outer part. Consequently, compared with the exact MoM, the new method saves much more memory resources and computation time, which provides a drastic reduction of unknowns.
Pedo-Transfer Functions to Estimate Kinetic Parameters for Anaerobic Soil Nitrogen Mineralization  [PDF]
Ganghua Zou, Fengliang Zhao, Ying Shan, Yong Li
Open Journal of Soil Science (OJSS) , 2018, DOI: 10.4236/ojss.2018.82006
Abstract: Knowledge of potential anaerobic soil N mineralization is important for nitrogen fertilizer application. Instead of time-consuming laboratory incubation, we attempt to use pedo-transfer functions (PTFs) approach to get this information. 27 soil samples with various soil depths were collected from paddy field, woodland and tea field in subtropical central China, anaerobically incubated at 35°C for 7 weeks to determine N mineralization, which was fitted by a modified double exponential model with two parameters (the fraction of active N pool (f) and mineralization rate constant (k) for active N pool). The PTFs for parameters were developed from significant soil properties using multiple stepwise regression method. Parameter f (range: 1.59% - 10.4%, mean: 5.2%) was mainly correlated with soil total N (TN), organic C (SOC), sand and silt particle contents (r = -0.59 - 0.69, p < 0.01), and parameter k (range: 0.027 - 0.155 d-1, mean: 0.97 d-1) was significantly related to TN, SOC, clay content, C to N ratio and pH (r = -0.6 - 0.71, p < 0.05). Three variables (SOC, silt and pH) could estimate parameter f (R2 = 0.72, p < 0.01) well and two (TN and pH) for parameter k (R2 = 0.61, p < 0.01). The developed PTFs, integrating various land uses and soil depths, suggest that basic soil properties are helpful for estimation of anaerobic soil N mineralization.
Information processing by a controlled coupling process
G. W. Wei,Shan Zhao
Physics , 2001,
Abstract: This Letter proposes a controlled coupling process for information processing. The net effect of conventional coupling is isolated from the dynamical system and is analyzed in depth. The stability of the process is studied. We show that the proposed process can locally minimize the smoothness and the fidelity of dynamical data. A digital filter expression of the controlled coupling process is derived and the connection is made to the Hanning filter. The utility and robustness of proposed approach is demonstrated by both the restoration of the contaminated solution of the nonlinear Schr\"{o}dinger equation and the estimation of the trend of a time series.
On the validity of "A proof that the discrete singular convolution (DSC)/Lagrange-distributed approximation function (LDAF) method is inferior to high order finite differences"
G. W. Wei,Shan Zhao
Mathematics , 2006, DOI: 10.1016/j.jcp.2007.05.036
Abstract: A few families of counterexamples are provided to "A proof that the discrete singular convolution (DSC)/Lagrange-distributed approximation function (LDAF) method is inferior to high order finite differences", Journal of Computational Physics, 214, 538-549 (2006).
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