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Search Results: 1 - 10 of 122270 matches for " Xuan Wang "
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Application of 3-D Parallel Electrical Technology Detecting the Water-Rich Areas  [PDF]
Xuan Wang, Liquan Guo
Open Journal of Geology (OJG) , 2014, DOI: 10.4236/ojg.2014.410038
Abstract: Coal working face is damaged more and more seriously by water below the coal face floor. Therefore, floor water detection is a must in the process of extraction. This article aims to introducing application and principle of the two-gateways parallel 3-D electrical technology and the arrangement of the observation system. The authors use this method to detect the water under the floor of a mine in north of Anhui. The results show that the two-gateways parallel 3-D electrical technology can accurately locate the water-rich areas, providing the basis for drilling drainage and grouting construction.
Feature Selection for Image Classification Based on a New Ranking Criterion  [PDF]
Xuan Zhou, Jiajun Wang
Journal of Computer and Communications (JCC) , 2015, DOI: 10.4236/jcc.2015.33013
Abstract:

In this paper, a feature selection method combining the reliefF and SVM-RFE algorithm is proposed. This algorithm integrates the weight vector from the reliefF into SVM-RFE method. In this method, the reliefF filters out many noisy features in the first stage. Then the new ranking criterion based on SVM-RFE method is applied to obtain the final feature subset. The SVM classifier is used to evaluate the final image classification accuracy. Experimental results show that our proposed relief- SVM-RFE algorithm can achieve significant improvements for feature selection in image classification.

Application of Distress Thermometer in Patients with Prostatic Cancer and Prostatitis  [PDF]
Xin Wang, Chang-Xuan Chen, Qian Wang, Lei Wang
Open Journal of Urology (OJU) , 2017, DOI: 10.4236/oju.2017.712027
Abstract: Objective: To discuss the application of distress thermometer (DT) on psychological pain in primary hospital patients with prostatic cancer (Pca) and prostatitis; and to analyze the present status and related factors of psychological pain in these patients. Methods: Questionnaire survey of DT and related problem lists were carried out in 168 patients with Pca and 226 patients with prostatitis. The data were input to EXCEL and analyzed with SPSS 18.0. The statistical description was used to analyze the graded of psychological pain. Square test and Logistic regression were used to analyze influence factors of significant psychological distress. Pearson correlation analysis was used to assess the correlation between psychological distress and related problems. Results: Psychological pain score of Pca patients and prostatitis patients were 3.42 ± 1.86 and 3.02 ± 1.75, respectively. Moderate to severe degree of pain accounted for 69.6% in Pca patients, compared to 49.1% in prostatitis patients. In Pca and prostatitis patients, marital status, age, educational backgrounds and income were associated. Physical and emotional problems were the top two items having the highest score. Psychological distress score was positively correlated with physical problems, emotional problems, practical problems and communication problems in both Pcar and prostatitis patients. Conclusion: The Distress Thermometer can be used to assess the severity and explore the causes of psychological distress in Pca patients and prostatitis patients. Our study could help detecting the degree and reason of psychological distress, and provide evidence for the possibility of future personalized intervention to treat medical mental problems in primary hospital.
Convergence Theorems for Common Fixed Points of a Finite Family of Relatively Nonexpansive Mappings in Banach Spaces
Yuanheng Wang,Weifeng Xuan
Abstract and Applied Analysis , 2013, DOI: 10.1155/2013/259470
Abstract:
Strong Uniform Attractors for Nonautonomous Suspension Bridge-Type Equations
Xuan Wang,Qiaozhen Ma
Mathematical Problems in Engineering , 2012, DOI: 10.1155/2012/714696
Abstract:
Strong Uniform Attractors for Nonautonomous Suspension Bridge-Type Equations
Xuan Wang,Qiaozhen Ma
Mathematical Problems in Engineering , 2012, DOI: 10.1155/2012/714696
Abstract: We discuss long-term dynamical behavior of the solutions for the nonautonomous suspension bridge-type equation in the strong Hilbert space , where the nonlinearity is translation compact and the time-dependent external forces only satisfy condition ( ) instead of translation compact. The existence of strong solutions and strong uniform attractors is investigated using a new process scheme. Since the solutions of the nonautonomous suspension bridge-type equation have no higher regularity and the process associated with the solutions is not continuous in the strong Hilbert space, the results are new and appear to be optimal. 1. Introduction Consider the following equations: Suspension bridge equations (1.1) have been posed as a new problem in the field of nonlinear analysis [1] by Lazer and McKenna in 1990. This model has been derived as follows. In the suspension bridge system, suspension bridge can be considered as an elastic and unloaded beam with hinged ends. denotes the deflection in the downward direction; represents the viscous damping. The restoring force can be modeled owing to the cable with one-sided Hooke’s law so that it strongly resists expansion but does not resist compression. The simplest function to model the restoring force of the stays in the suspension bridge can be denoted by a constant times , the expansion, if is positive, but zero, if is negative, corresponding to compression; that is, , where Besides, the right-hand side of (1.1) also contains two terms: the large positive term corresponding to gravity, and a small oscillatory forcing term possibly aerodynamic in origin, where is small. There are many results for (1.1) (cf. [1–9]), for instance, the existence, multiplicity, and properties of the traveling wave solutions, and so forth. In the study of equations of mathematical physics, attractor is a proper mathematical concept about the depiction of the behavior of the solutions of these equations when time is large or tends to infinity, which describes all the possible limits of solutions. In the past two decades, many authors have proved the existence of attractor and discussed its properties for various mathematical physics models (e.g., see [10–12] and the reference therein). About the long-time behavior of suspension bridge-type equations, for the autonomous case, in [13, 14] the authors have discussed long-time behavior of the solutions of the problem on and obtained the existence of global attractors in the space and . It is well known that, for a model to describe the real world which is affected by many kinds of factors,
Strong Pullback Attractors for Nonautonomous Suspension Bridge Equations
Wenchao Ju,Xuan Wang
ISRN Applied Mathematics , 2014, DOI: 10.1155/2014/253532
Abstract: We prove the existence of a pullback -attractor in for the nonautonomous suspension bridge equations. 1. Introduction In this paper, we consider the following nonautonomous suspension bridge equation: where is a bounded domain of with a smooth boundary , is an unknown function, which could represent the deflection of the road bed in the vertical plane, represents the restoring force, denotes the spring constant, represents the viscous damping, and is a given positive constant. Suspension bridge equations have been posed as a new problem in the field of nonlinear analysis [1] by Lazer and Mckenna in 1990. There are many results for the problem (1) (cf. [1–8]), for instance, the existence, multiplicity, and properties of the travelling wave solutions, and so forth. About the long-time behavior of suspension bridge equations, for the autonomous case, in [9, 10], the authors have discussed long-time behavior of the solutions of the problem on and obtained the existence of global attractors in the space and . Caraballo et al. advanced the concept of the pullback -attractor in [11], and the existence of the pullback attractors was proved under the assumptions of asymptotic compactness and existence of a family of absorbing sets. Recently, Park and Kang [12] studied the pullback -attractor for suspension bridge equations in the weak space . Motivated by the ideas of [11, 13], we study the existence of a strong pullback -attractor for the nonautonomous suspension bridge equations in the strong topological space . The nonlinear functions satisfy the following assumptions: where constant . With the usual notation, we introduce the spaces , , where . We equip these spaces with inner product and norm?? , , and , respectively: Obviously, we have where is dual space of , respectively; the injections are continuous and each space is dense in the following one. Choosing , by the Poincaré inequality, we have We introduce the Hilbert spaces and endow this space with norm This paper is organized as follows. At first, in Section 2, we recall some preliminaries and results concerning the pullback attractor. Then, in Section 3, we prove our main result about the existence of pullback -attractor for the nonautonomous dynamical system generated by the solution of (1). 2. Notation and Preliminaries Let be a complete metric space, be a metric space which will be called the parameter space. We define a nonautonomous dynamical system by a cocycle mapping which is driven by an autonomous dynamical system acting on a parameter space . Specifically, is a dynamical system on ; that
Asymptotic behavior of extremal functions to an inequality involving Hardy potential and critical Sobolev exponent
Benjin Xuan,Jiangchao Wang
Mathematics , 2007,
Abstract: In this paper, we study the asymptotic behavior of radial extremal functions to an inequality involving Hardy potential and critical Sobolev exponent. Based on the asymptotic behavior at the origin and the infinity, we shall deduce a strict inequality between two best constants. Finally, as an application of this strict inequality, we consider the existence of nontrivial solution of a quasilinear Brezis-Nirenberg type problem with Hardy potential and critical Sobolev exponent.
Effects of Silica Sol on Structure and Properties of Core-Shell Silicon-Acrylic Materials  [PDF]
Xuan Li, Yiding Shen, Haihua Wang, Guiqiang Fei
Advances in Chemical Engineering and Science (ACES) , 2012, DOI: 10.4236/aces.2012.22023
Abstract: Silica sol prepared by sol-gel method was introduced into poly (butyl acrylate) (PBA)/poly (butyl acrylate-styrene-methacryloxypropyl trimethoxysilane) (PSBM) core-shell emulsions to prepare a series of paper surface sizing agents. The rheological measurement indicated that PSBM emulsions exhibited shear-thinning behavior, and the phenomena became more pronounced with increasing silica sol concentration. Dynamic mechanical analysis (DMA) demonstrated that the stronger interfacial interaction between silica sol and polymer matrix, but microphase separation took place with excess silica sol. Thereby the tensile strength and thermal stability of emulsion films were increased with desirable silica sol concentration, and when silica sol concentration was greater than 6 wt%, the tensile strength leveled off and the decomposition temperature decreased from 351.19℃ to 331.63℃. The degree of crystallinity increased from 5.12% to 10.98% with 4% silica sol addition, resulting in enhanced rigidity of films. Furthermore, the interaction between polymer and fiber was improved with certain amount of silica sol, resulting in improved sizing degree, ring crush strength, surface strength and folding strength. However, excessive crosslinking will be harmful for the properties of sized paper.
Fault Ride-Through Study of Wind Turbines  [PDF]
Xinyan Zhang, Xuan Cao, Weiqing Wang, Chao Yun
Journal of Power and Energy Engineering (JPEE) , 2013, DOI: 10.4236/jpee.2013.15004
Abstract: The installation of wind energy has increased rapidly around the world. The grid codes about the wind energy require wind turbine (WT) has the ability of fault (or low voltage) ride-through (FRT). To study the FRT operation of the wind farms, three methods were discussed. First, the rotor short current of doubly-fed induction generator (DFIG) was limited by introducing a rotor side protection circuit. Second, the voltage of DC bus was limited by a DC energy absorb circuit. Third, STATCOM was used to increase the low level voltages of the wind farm. Simulation under MATLAB was studied and the corresponding results were given and discussed. The methods proposed in this paper can limit the rotor short current and the DC voltage of the DFIG WT to some degree, but the voltage support to the power system during the fault largely depend on the installation place of STATCOM.
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