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Search Results: 1 - 10 of 63180 matches for " Shuang Yu "
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Study on Viscoelastic Behaviors of Waxy Crude Water-in-Oil Emulsion  [PDF]
Liping Guo, Shuang Shi, Yu Wang
Advances in Chemical Engineering and Science (ACES) , 2016, DOI: 10.4236/aces.2016.62022
Abstract: Emulsion of waxy crude oil is one of the common states in the subsea pipeline. At low temperatures in offshore environment, waxy crude oils with water could form the crude oil emulsion gel of oil-in-water emulsion. Thus, the waxy crude oil emulsion viscoelastic behavior for deep sea transportation and restarting pipeline safety is particularly important. By means of MASIII HAAKE rheometer which is produced by German company, waxy crude oil emulsion viscoelastic behavior is explored at different volumetric water contents and different shear stresses. By analyzing the rate of change of shear rate in the initial stage, the influence rules of viscoelastic properties were summarized, with the change of volumetric water content and the applied shear stress and based on the experimental results, the law of emulsion is explained from the micro level. It is proposed that brittle fracture exists between wax crystals, and flexible fracture was found in the interaction between water droplets and wax crystals.
Research on Casing Damage Based on Effect of Water Injection Pressure  [PDF]
Liping Guo, Xu Chen, Xiaoyang Yu, Shuang Shi, Yu Wang
Open Journal of Fluid Dynamics (OJFD) , 2015, DOI: 10.4236/ojfd.2015.52023
Abstract: Based on statistical analysis on the situation of casing damage and water injection pressure in Pubei Oilfield, it shows that the main forms of casing damage in Pubei Oilfield are deformation and dislocation. Dip angle and faults have a significant impact on casing damage and casing damage is closely related to water injection pressure. Through laboratory simulating experiment and theoretical calculation, the formula of critical injection pressure giving rise to casing damage is obtained and the preventive measures are drafted.
Evaluation of Thixotropic Models for Waxy Crudes  [PDF]
Liping Guo, Xu Chen, Shuang Shi, Yu Wang, Xiaoyang Yu
Open Journal of Applied Sciences (OJAppS) , 2015, DOI: 10.4236/ojapps.2015.56031
Abstract: Thixotropy is a great rheological behavior of waxy crudes oils and is of great importance for hydraulic characteristics and security of oil pipeline restart. In this paper, through the experiment of four waxy crudes, three kinds of thixotropic rheology characteristics in the conditions that shear stress decays under a constant shear rate, shear stress decays after shear rate steps up and hysteresis loop of shear rate cycle changes are studied . For eight thixotropic models, experimental data are fitted in the method of least-squares and average deviation is taken as a statistical indicator to evaluate the thixotropic models. It shows that the model with the idea of Cheng that completely reversible and totally irreversible structures both exist in waxy oil products and based on Houska model can describe thixotropic behaviors of waxy crudes most well.
Study on Thixotropic Properties of Waxy Crude Oil Based on Hysteresis Loop Area  [PDF]
Liping Guo, Yu Wang, Shuang Shi, Xiaoyang Yu, Xu Chen
Engineering (ENG) , 2015, DOI: 10.4236/eng.2015.77043
Abstract: Thixotropic properties are one of the low temperature rheology behaviors of gelled waxy crudes. In order to study the thixotropic behavior of gelled waxy crudes oil under cyclic loading of linear increasing and decreasing of shear rate, three different types of waxy crude oil were studied ex-perimentally by using MARSIII rheometer. It is found that hysteresis loop area could represent strength of thixotropic properties under that loading. With increasing of the rate of share rate sweep, the area of second hysteresis loop is much smaller than first one and began a slow decline from the third hysteresis loop. Areas of each hysteresis loops were decreased with increasing temperature, but it was different in decline rate—the lower the temperature, the greater the rate of decline. The maximum rate of decrease is the first hysteresis loop with exponential decline, and remaining hysteresis hoops approximately decrease linearly. In addition, based on the experi-mental results an empirical correlation is developed to describe the relationship of hysteresis loop area and rate of share rate sweep.
On the formation of shocks for quasilinear wave equations
Shuang Miao,Pin Yu
Mathematics , 2014,
Abstract: The paper is devoted to the study of shock formation of the 3-dimensional quasilinear wave equation \begin{equation}\label{Main Equation} - \big(1+3G^{\prime\prime}(0) (\partial_t\phi)^2\big)\partial^2_t \phi +\Delta\phi=0,\tag{\textbf{$\star$}} \end{equation} where $G^{\prime\prime}(0)$ is a non-zero constant. We will exhibit a family of smooth initial data and show that the foliation of the incoming characteristic hypersurfaces collapses. Similar to 1-dimensional conservational laws, we refer this specific type breakdown of smooth solutions as shock formation. Since $(\star)$ satisfies the classical null condition, it admits global smooth solutions for small data. Therefore, we will work with large data (in energy norm). Moreover, no symmetry condition is imposed on the initial datum. We emphasize the geometric perspectives of shock formations in the proof. More specifically, the key idea is to study the interplay between the following two objects: (1) the energy estimates of the linearized equations of $(\star)$; (2) the differential geometry of the Lorentzian metric $g=-\dfrac{1}{\left(1+3G^{\prime\prime}(0) (\partial_t\phi)^2\right)} d t^2+dx_1^2+dx_2^2+dx_3^2$. Indeed, the study of the characteristic hypersurfaces (implies shock formation) is the study of the null hypersurfaces of $g$. The techniques in the proof are inspired by the work \cite{Ch-Shocks} in which the formation of shocks for $3$-dimensional relativistic compressible Euler equations with small initial data is established. We also use the short pulse method which is introduced in the study of formation of black holes in general relativity in \cite{Ch-BlackHoles} and generalized in \cite{K-R-09}.
Threshold-belt Barization Method Research of High Sampling Density Gray-coded Image
Xiaoyang Yu,Lina Shan,Shuang Yu
Information Technology Journal , 2010,
Abstract: In order to enhance the quality of high sampling density gray code image binarization, a threshold-belt binarization method is proposed in this study. First of all, by using this method, we need to establish a single threshold and then, according to the dispersion of the background and objectives, respectively with the single threshold, we set up a collection of threshold-belts. By removing the sampling points in the threshold belt, binary the sampling points outside of the threshold belt in order to get background and objectives, namely, the fact that the black and white stripes of the gray code image. This method avoids the phenomenon of misjudgments of the gray-scale sampling points near the single threshold. It also improves anti-interference ability of the image binarization and accuracy of the measurement.
The role of intracellular sodium (Na+) in the regulation of calcium (Ca2+)-mediated signaling and toxicity  [PDF]
Xian-Min Yu, Bradley R. Groveman, Xiao-Qian Fang, Shuang-Xiu Lin
Health (Health) , 2010, DOI: 10.4236/health.2010.21002
Abstract: It is known that activated N-methyl-D-aspartate receptors (NMDARs) are a major route of ex-cessive calcium ion (Ca2+) entry in central neu-rons, which may activate degradative processes and thereby cause cell death. Therefore, NMD- ARs are now recognized to play a key role in the development of many diseases associated with injuries to the central nervous system (CNS). However, it remains a mystery how NMDAR ac-tivity is recruited in the cellular processes leading to excitotoxicity and how NMDAR activ-ity can be controlled at a physiological level. The sodium ion (Na+) is the major cation in ex-tracellular space. With its entry into the cell, Na+ can act as a critical intracellular second mes-senger that regulates many cellular functions. Recent data have shown that intracellular Na+ can be an important signaling factor underlying the up-regulation of NMDARs. While Ca2+ influx during the activation of NMDARs down-regu-lates NMDAR activity, Na+ influx provides an essential positive feedback mechanism to over- come Ca2+-induced inhibition and thereby po-tentiate both NMDAR activity and inward Ca2+ flow. Extensive investigations have been con-ducted to clarify mechanisms underlying Ca2+- mediated signaling. This review focuses on the roles of Na+ in the regulation of Ca2+-mediated NMDAR signaling and toxicity.
Chinese Culture and Modern Life—On the Theory of Resources and Basic Context of Chinese Cultural Soft Power to Enhance
Wei GUAN,Shuang,Quanjiao YU
Cross-Cultural Communication , 2012, DOI: 10.3968/j.ccc.1923670020120806.zrgly
Abstract: To enhance the soft power of Chinese culture, an important issue is to analyze and clean up the theory of cultural soft power resources and the Current Context. Cultural soft power to enhance the theoretical resources that is Chinese traditional culture, Context that enhance cultural soft power is the modern life. But, traditional culture is not a dead, past existence, but a process of constant development; the modern life is not the life style and the thinking mode which the West leads; traditional culture is a national, special, modern life is also diverse, optional. Key words: Soft power; Tradition; Traditional culture; Modern life
Inverse volume corrections to emergent tachyonic inflation in loop quantum cosmology
Puxun Wu,Shuang Nan Zhang,Hongwei Yu
Physics , 2009, DOI: 10.1088/1475-7516/2009/05/007
Abstract: The emergent model in the context of loop quantum cosmology with a tachyon scalar field is studied. We find that there is a center equilibrium point in the semiclassical region and a saddle point in the classical region. If the potential of the tachyon field satisfies some conditions, the universe can stay at the center equilibrium point past-eternally and then oscillate infinitely around this point with the tachyon climbing up its potential. Once the potential reaches a critical value, these two equilibrium points coincide with each other and the oscillation phase is broken by an emergent inflation. In order to obtain a successful emergent tachyon inflation, a constraint on $\dot{\phi}^2$ of tachyon is required.
Landau-Zener-Stückelberg Spectroscopy of a Superconducting Flux Qubit
Shuang Xu,Guozhu Sun,Yang Yu
Physics , 2010, DOI: 10.1103/PhysRevB.82.144526
Abstract: We proposed a new method to measure the energy spectrum of a superconducting flux qubit. Different from the conventional frequency spectroscopy, a short triangle pulse is used to drive the qubit through the anticrossing and generates Landau-Zener-St\"uckelberg interference patterns, from which the information of the energy spectrum can be extracted. Without installing microwave lines one can simplify the experimental setup and reduce the unwanted effects of noise. Moreover, the method can be applied to other quantum systems, opening the possibility of calibrating and manipulating qubits with linear pulses.
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