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Search Results: 1 - 10 of 75628 matches for " Dong Y "
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Target mass corrections to matrix elements in nucleon spin structure functions
Dong, Y. B.
High Energy Physics - Phenomenology , 2008, DOI: 10.1103/PhysRevC.78.028201
Abstract: Target mass corrections to the twist-4 terms $\tilde f_2^{p,n,d}$ as well as to the leading-twist $\tilde a_2$ are discussed.
Target mass corrections and twist-3 in the nucleon spin structure functions
Dong, Y. B.
High Energy Physics - Phenomenology , 2007, DOI: 10.1016/j.physletb.2007.07.022
Abstract: The Nachtmann moment is employed to study the contribution of twist-3 operator to the nucleon spin structure functions. Target mass corrections to the Cornwall-Norton moments of the spin structure functions $g_{1,2}$ are discussed. It is found that the corrections play a sizeable role to the contribution of the twist-3 $\tilde d_2$ extracted from the Cornwall-Norton moments.
Modeling of Asphaltene Grading in Oil Reservoirs  [PDF]
Julian Y. Zuo, Oliver C. Mullins, Chengli Dong, Dan Zhang
Natural Resources (NR) , 2010, DOI: 10.4236/nr.2010.11003
Abstract: Reservoir fluids frequently reveal complex phase behaviors in hydrocarbon columns owing to the effects of gravity, thermal diffusion, biodegradation, active charging, water washing, seals leaking, and so on. In addition, the formation compartmentalization often causing discontinuous distributions of fluid compositions and properties makes the proper fluid characterization and reservoir architecture even more challenging yet compelled. The recognition of compositional grading and flow barriers becomes a key to accurate formation evaluation in a cost effective manner. Downhole fluid analysis (DFA) of asphaltene gradients provides an excellent method to delineate the complexity of black oil columns. In this paper, a methodology was developed to estimate downhole asphaltene variations with depths using an equation-of-state (EOS) approach coupled with DFA measurements. DFA tools were used to determine fluid compositions of CO2, C1, C2, C3-C5, C6+, gas-oil ratio (GOR), density and the coloration (optical density) associated with asphaltene contents at downhole conditions. The delumping and characterization procedures proposed by Zuo et al. (2008) were employed to obtain the detailed compositions excluding asphaltenes. In addition, a molar mass distribution of asphaltenes was described by a three-parameter Gamma probability function. The Gaussian quadrature method was used to generate asphaltene pseudocomponents. Five pseudocomponents were employed to represent the normal asphaltene nanoaggregates. Asphaltene distributions in oil columns were computed by tuning the molar mass of asphaltene nanoaggregates against the DFA coloration logs at a reference depth. The methodology was successfully applied to investigate black oil reservoir connectivity (or flow barriers) for offshore field cases. The analysis results were consistent with the subsequent production data and analytical chemistry. Furthermore, for simplicity, it is reasonable to assume that asphaltenes have average properties such as molar mass in entire oil columns. The results obtained in this work demonstrate that the proposed method provides a useful tool to reduce the uncertainties related to reservoir compartmentalization and to optimize the DFA logging during acquisition.
Swarm Intelligence in Power System Planning  [PDF]
Ke Meng, Z.Y. Dong, Yichen Qiao
International Journal of Clean Coal and Energy (IJCCE) , 2013, DOI: 10.4236/ijcce.2013.22B001
Abstract: Power system planning is one of the essential tasks in the power system operation management, which requires in-depth knowledge of the system under consideration. It can be regarded as a nonlinear, discontinuous, constrained multi objective optimization problem. Although the traditional optimization tools can be used, the modern planning problem requires more advanced optimization tools. In this paper, a survey of state-of-the-art mathematical optimization methods that facilitates power system planning is provided, and the needs of introducing swarm intelligence approaches into power system planning are discussed.
Secure Chained Threshold Proxy Signature without and with Supervision  [PDF]
Zoe L. JIANG, S. M. YIU, Y. DONG, L. C. K. HUI, S. H. Y. WONG
Journal of Software Engineering and Applications (JSEA) , 2009, DOI: 10.4236/jsea.2009.24034
Abstract: Threshold Proxy Signature (TPS) scheme facilitates a manager to delegate his signing capability to a group of n2 sub-ordinates without revealing his own private key, such that a subgroup of at least t2 ≤ n2 subordinates is required to generate a proxy signature. In reality, the situation can be more complicated. First of all, the subgroup may further delegate their proxy signing capabilities to another group of n3 subordinates such that at least another subgroup of at least t3 ≤ n3 subordinates are of the proxy signing capabilities (in the form of a chain). t2 can be unequal to t3 depending on the concrete requirement. This is a group-to-group delegation problem. In addition, a supervising agent (SA) may be introduced in the above chain to supervise the subordinates, such that proxy signing can only be successfully executed with SA’s agreement. This is a delegation with supervision problem in the threshold delegation chain described above. These two extensions of delegation problems are not solved yet. This paper designs two provably secure cryptographic schemes Chained Threshold Proxy Signature (CTPS) scheme and Chained Threshold Proxy Signature with Supervision (CTPSwS) scheme to solve these two delegation problems.
Research on a Methodology to Model Speech Emotion
Y.U. Dong Mei,Y.U. Dong Mei
Journal of Engineering and Applied Sciences , 2012,
Abstract: Research was conducted to develop a methodology to model the emotional content of speech as a linear function of time and speech features. In this study, emotional type is coming from 6 base emotions (anger, disgust, fear, joy, sadness and surprise). But, in the application is not defined as a simple word, is quantified using the dimensions valence and arousal and the value of valance or arousal is expressed as some interval. Results demonstrate that the model is more excellence than others.
An Optimal Control Model and the Computer Algorithm for the Diffusion Parameter of the Drug Releasing in the Spherical Device
Y. Li,Y. Li,M. Dong,M. Dong
Information Technology Journal , 2012,
Abstract: In this study, we established an optimization control model and the corresponding computer algorithm to estimate the diffusion coefficient of the drug releasing in the spherical device. First, based on the diffusion equation in the spherical device in the polar coordinates system, the optimal control model was given to compute the diffusion coefficient in the drug releasing problem in the sphere device. Next, the Least Square Method based on the Separation Variables (LSMSV) was used to solve the problem to estimate the appropriate diffusion coefficient. Finally, a numerical example was presented to show that the control model and the numerical method are valid for computing the diffusion coefficient of the drug releasing in the sphere device.
Form factors in relativistic quantum mechanics: constraints from space-time translations
Desplanques, B.;Dong, Y. B.
High Energy Physics - Phenomenology , 2008,
Abstract: The comparison of form factors calculated from a single-particle current in different relativistic quantum mechanic approaches evidences tremendous discrepancies. The role of constraints coming from space-time translations is considered here with this respect. It is known that invariance under these translations implies the energy-momentum conservation relation that is usually assumed to hold globally. Transformations of the current under these translations, which lead to this result, also imply constraints that have been ignored so far in relativistic quantum mechanic approaches. An implementation of these constraints is discussed in the case of a model with two scalar constituents. It amounts to incorporate selected two-body currents to all orders in the interaction. Discrepancies for form factors in different approaches can thus be removed, contributing to restore the equivalence of different approaches. Results for the standard front-form approach ($q^+=0$) are found to fulfill the constraints and are therefore unchanged. The relation with results from a dispersion-relation approach is also made.
Statistical equilibrium and ion cyclotron absorption/emission in strongly magnetized plasmas
A. Y. Potekhin,Dong Lai
Physics , 2007, DOI: 10.1111/j.1365-2966.2007.11474.x
Abstract: We calculate the transition rates between proton Landau levels due to non-radiative and radiative Coulomb collisions in an electron-proton plasma with strong magnetic field B. Both electron-proton collisions and proton-proton collisions are considered. The roles of the first-order cyclotron absorption and second-order free-free absorption and scattering in determining the line strength and shape as well as the continuum are analysed in detail. We solve the statistical balance equation for the populations of proton Landau levels. For temperatures \sim 10^6-10^7 K, the deviations of the proton populations from LTE are appreciable at density \rho < 0.1 B_{14}^{3.5} g cm^{-3}, where B_{14}=B/(10^{14} G). We present general formulae for the plasma emissivity and absorption coefficents under a wide range of physical conditions. Our results are useful for studying the possibility and the conditions of proton/ion cyclotron line formation in the near vicinity of highly magnetized neutron stars.
Form factors in relativistic quantum mechanics: constraints from space-time translations
B. Desplanques,Y. B. Dong
Physics , 2008,
Abstract: The comparison of form factors calculated from a single-particle current in different relativistic quantum mechanic approaches evidences tremendous discrepancies. The role of constraints coming from space-time translations is considered here with this respect. It is known that invariance under these translations implies the energy-momentum conservation relation that is usually assumed to hold globally. Transformations of the current under these translations, which lead to this result, also imply constraints that have been ignored so far in relativistic quantum mechanic approaches. An implementation of these constraints is discussed in the case of a model with two scalar constituents. It amounts to incorporate selected two-body currents to all orders in the interaction. Discrepancies for form factors in different approaches can thus be removed, contributing to restore the equivalence of different approaches. Results for the standard front-form approach ($q^+=0$) are found to fulfill the constraints and are therefore unchanged. The relation with results from a dispersion-relation approach is also made.
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