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Search Results: 1 - 10 of 39305 matches for " LV Yan "
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Numerical Simulation of Fluid Structure Interaction between Flow and Steel Pipe Pile Platform in Deep Water  [PDF]
Wenyue Yan, Fengwu Lv
World Journal of Engineering and Technology (WJET) , 2016, DOI: 10.4236/wjet.2016.43C011
In this paper, the two-way coupling of flow and steel pipe pile platform is simulated by ANSYS Workbench. Taking the construction platform in the deep water area of the Yangtze River Estuary as an example, the stress and deformation characteristics of the steel pipe pile platform under current force are analyzed in detail. As a result, it is suggested the platform piles should be arranged regularly and the connected node de-sign of the platform structure should be strengthened to ensure the safety.
A Target Tracking Algorithm Based on Improved Camshift and UKF  [PDF]
Zouguo Yan, Weiguo Liang, Haidong lv
Journal of Software Engineering and Applications (JSEA) , 2014, DOI: 10.4236/jsea.2014.713094
Abstract: A tracking algorithm based on improved Camshift and UKF is proposed in this paper to deal with the problems which exist in traditional Camshift algorithm, such as artificial orientation and tracking failure under color interference as well as object’s changed illumination occlusion. Meanwhile, in order to solve the sheltered problem, the UKF is combined with improved Camshift algorithm to predict the position of the target effectively. Experiment results show that the proposed algorithm can avoid the interference of the background color and solve the sheltered problem of the object, so that achieving a precise and timely tracking of moving objects. Also it has better robustness to color noises and occlusion when the object’s scale changes and deformation occurs.
The Effect of Psychological Capital and Knowledge Sharing on Innovation Performance for Professional Technical Employees  [PDF]
Xiaowei Qiu, Xiaocen Yan, Yanle Lv
Journal of Service Science and Management (JSSM) , 2015, DOI: 10.4236/jssm.2015.84055
Abstract: Professional technical employees are the core staff to maintain the normal operation of the organization and the backbone of the workforce. Their levels of innovation influence and restrict the overall innovation performance levels of the corporation to a large extent. Therefore, it is of vital importance to explore and develop the innovation performance of the professional technical employees. The research, combining the theories of psychological capital, is aimed at examining the effect of psychological capital on innovation performance of the professional technical employees through the angle of knowledge sharing. Based on the hierarchical regression analysis of 347 questionnaires, the study finds that the psychological capital of the employees has a significant positive effect on the innovation performance. Meanwhile, knowledge sharing plays a completely mediating role. The corporation should lay emphasis on the psychological capital and create an atmosphere of learning organization, so as to improve and enhance the innovation performance of employees.
Edge Detection of Composite Insulators Hydrophobic Image Based on Improved Canny Operator  [PDF]
Kang Yan, Fochi Wang, Zhongyuan Zhang, Ningcai Li, Fangcheng Lv
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.54B114

The detection of hydrophobicity is an important way to evaluate the performance of composite insulators, which is helpful to the safe operation of composite insulators. Image processing technology is used to judge the hydrophobicity of composite insulators, which makes detection results more accurate and overcomes the subjective drawbacks of traditional detection methods. As the traditional Canny operator requires manual intervention in selecting the variance of the Gaussian filter and the threshold, the paper presents a method of edge detection based on improved Canny operator. First, the adaptive median filter replaces the Gaussian filter, which can eliminate the impact from the variance of Gaussian filter and remove noise according to the characteristics of the image itself. Then the Ostu threshold method is used to select the best threshold automatically, which makes the edge detection be more continuous and reduce the presence of fake edges. The results show that the operator is applicable to all hydrophobic images.

Metastasia Lesion of Gestation Trophoblastic Tumor in Abdominopelvic Cavity Diagnosed by Sonographic and Doppler Imaging  [PDF]
Guozhen Yan, Yanfen Yuan, Yang Liu, Yunmei Lv, Aihua Li
Open Journal of Clinical Diagnostics (OJCD) , 2015, DOI: 10.4236/ojcd.2015.51005
Abstract: Objective: The purpose of this study was to review clinical data of metastasia lesion of gestation trophoblastic tumor (GTT) in abdominopelvic cavity by color Doppler ultrasound. Subjects and Methods: A retrospective analysis of 13 cases of GTT in China was performed. Clinical appearances, serum human chorionic gonadotropin (hCG) levels, sonographic findings, Doppler waveforms, and patient outcomes were followed up. Color Doppler ultrasound was performed to diagnose the presence of GTT, detect metastasia lesion in abdominopelvic cavity, assess disease recurrence, and monitor the efficacy of chemotherapy. Results: Of the 13 patients with GTT, 4 had choriocarcinoma which 3 cases occurred after an abortion, 1 after a year of dilation and suction evacuation for the hydatidform mole. Metastasia lesion in abdominopelvic cavity was detected by color Doppler ultrasound in all cases of choriocarcinoma, among which the metastasia lesion were found at uterine fundus, near uterus, colon and cystic vascular space near the uterus, repectively. 9 cases with an invasive hydatidiforn mole (IHM) occurred after one to three months of dilation and suction evacuation for the hydatidform mole, consistant with the hCG levels markedly elevating. Metastasia lesion in abdominopelvic cavity was also detected by color Doppler ultrasound besides invasive lesion in uterine muscular layer in all cases of IHM, among which 3 cases showed metastasia lesion in cystic vascular space near the uterus, 2 cases were detected in side wall of pelvic cavity, while the rest were found in abdominal cavity, right kidney, colon and near uterus, respectively. Meanwhile, the image of metastasia lesion with IHM was similar to choriocarcinoma’s. And the reticular structure, the cystic vascular space and solid lesion may be showed by ultrasound. The metastasia lesion had abundant flow. Doppler waveforms showed resistive indices of 0.34 (SD 0.07) for metastasia lesion. There was the same lower-impedance as invasive lesion in uterine muscular layer. Except an IHM with the renal metastasia lesion having been followed, abnormal sonographic and Doppler findings in other metastasia disease all disappeared after surgical operation or chemotherapy were successful. Conclusions: Sonography and Doppler imaging were helpful in detecting metastasia lesion in abdominopelvic cavity, and in following the effectiveness of chemotherapy. And it should be taken full examination for GTT by Color Doppler ultrasound in order to avoid mistake.
Averaging approximation to singularly perturbed nonlinear stochastic wave equations
Yan Lv,A. J. Roberts
Mathematics , 2011, DOI: 10.1063/1.4726175
Abstract: An averaging method is applied to derive effective approximation to the following singularly perturbed nonlinear stochastic damped wave equation \nu u_{tt}+u_t=\D u+f(u)+\nu^\alpha\dot{W} on an open bounded domain $D\subset\R^n$\,, $1\leq n\leq 3$\,. Here $\nu>0$ is a small parameter characterising the singular perturbation, and $\nu^\alpha$\,, $0\leq \alpha\leq 1/2$\,, parametrises the strength of the noise. Some scaling transformations and the martingale representation theorem yield the following effective approximation for small $\nu$, u_t=\D u+f(u)+\nu^\alpha\dot{W} to an error of $\ord{\nu^\alpha}$\,.
Study on the Diurnal Changes of Net Photosynthetic Rate and the Impact Factors of Stevia rebaudiana Bertoni in Autumn
Lv Chengguo,Ma Lei,Shi Yan
American Journal of Plant Physiology , 2009,
Abstract: Relationship between diurnal changes of net photosynthetic rate (Pn) and the impact factors in leaves of Stevia rebaudiana Bertoni were studied. Diurnal changes of Pn and environmental factors (photosynthetic available radiation and temperature and relative humidity) and physiology factors (stomatal conductance and transpiration rate and intercellular CO2) in leaves of Stevia rebaudiana Bertoni chicory were measured using LI-6400 portable photosynthesis system. The relationship between Pn and environmental factors were analyzed by regression analysis and path analysis. The results showed that the curve of diurnal changes of Pn was demonstrated two peaks in clear day and appeared midday depression at noon and the stomatal conductance decreased. All those were due to high photorespiration which was caused by high light intensity and high temperature.
The Effect of Steviol Glycosides Blending Liquid on Senescence after Flowering in Upland Rice
Yu Congmin,Lv Chengguo,Shi Yan
Journal of Agronomy , 2009,
Abstract: The effect of steviol glycosides blending liquid (SBL) on senescence after flowering in upland rice had been studied. By measured the superoxide dismutase (SOD) activity in using NBT method to inhibit photoreduction activity NBT 50% for a units; malondialdehyde (MDA) content by using the two-component spectrophotometry and also the catalase (CAT) activity measured by the method of ammonium molybdate. The results showed with different concentrations of SBL sprayed, the SOD activity and CAT activity in upland rice increased, the MDA content in rice flag leaves reduced. Compared the treatment of different concentration, the middle concentration was found to be the best one. The SOD activity could been kept the highest activity until 15 days after flowering in the middle concentration, but it could been started to be down at 5 days after flowering in control and the treatment of low concentration and high concentration. The MDA content increased slowly in the middle concentration and increased rapidly in control and the treatment of low concentration and high concentration. The CAT activity was significantly higher in the treatment of middle concentration and high concentration than that in the low-concentration and control at 5 days after flowering. So, the treatment of middle concentration of SBL has the best effect in delaying senescence of flag leaves.
Approximation of the random inertial manifold of singularly perturbed stochastic wave equations
Yan Lv,Wei Wang,Anthony Roberts
Mathematics , 2012,
Abstract: By applying Rohlin's result on the classification of homomorphisms of Lebesgue space, the random inertial manifold of a stochastic damped nonlinear wave equations with singular perturbation is proved to be approximated almost surely by that of a stochastic nonlinear heat equation which is driven by a new Wiener process depending on the singular perturbation parameter. This approximation can be seen as the Smolukowski--Kramers approximation as time goes to infinity. However, as time goes infinity, the approximation changes with the small parameter, which is different from the approximation on a finite interval.
On the approximation for singularly perturbed stochastic wave equations
Wei Wang,Yan Lv,A. J. Roberts
Mathematics , 2011,
Abstract: We explore the relation between fast waves, damping and imposed noise for different scalings by considering the singularly perturbed stochastic nonlinear wave equations \nu u_{tt}+u_t=\D u+f(u)+\nu^\alpha\dot{W} on a bounded spatial domain. An asymptotic approximation to the stochastic wave equation is constructed by a special transformation and splitting of $\nu u_{t}$. This splitting gives a clear description of the structure of $u$. The approximating model, for small $\nu>0$\,, is a stochastic nonlinear heat equation for exponent $0\leq\alpha<1$\,, and is a deterministic nonlinear wave equation for exponent $\alpha>1$\,.
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