Photon Production from a Quark-Gluon-Plasma at Finite Baryon Chemical Potential

We compute the photon production of a QCD plasma at leading order in the strong coupling with a finite baryon chemical potential. Our approach starts from the real time formalism of finite temperature field theory. We identify the class of diagrams contributing at leading order when a finite chemical potential is added and resum them to perform a full treatment of the LPM effect similar to the one performed by Arnold, Moore, and Yaffe at zero chemical potential. Our results show that the contribution of $2\mapsto 3$ and $3\mapsto 2$ processes grows as the chemical potential grows.Comment: 28 pages, 14 figure

Research of Variable Volume and Gas Injection DC Inverter Air Conditioning Compressor

With the wide promotion of energy saving and environmental protection, the improvement of heating capacity especially at low ambient temperature condition and the working efficiency of room air conditioner become more and more important. Firstly, the purpose of this paper was introduced. Then, the relative techniques like DC inverter, variable volume and gas injection were simply analyzed. Thirdly, a new coupling compressor with these three techniques to satisfy both heating capacity and efficiency demands was indicated. Moreover, the detail design of the coupling compressor was described. At last, the prototype compressor was designed and assembled to validate the effect of this coupling compressor on RAC system. According to the test result, this coupling compressor has significant effect as we expectation when using in RAC system. The maximum heating capacity increasing up to 185% by compare to the base system at -15℃ ambient temperature condition which makes half time consumption at the same room temperature rising. Furthermore, the APF efficiency of the system increased by about 6%

Understanding the effects of doctors’ online profile pictures on patients’ decision-making

The effect of doctors’ profile pictures in online healthcare platforms has been investigated in prior research. However, little attention has focused on professional signals conveyed by doctors’ online profile pictures. To address the above-mentioned gap, this study examines the roles of doctors’ profile pictures in patients’ online decision-making based on cue utilization theory and impression management theory. Our research finds that a picture indicating professional information (e.g., professional attire and professional background) matters in attracting patients’ interest and their decision-making. However, the impacts of professional information change according to patients’ illness severity. Specifically, patients with low-severity illnesses care more about professional attire in the stage of glancing physicians, while patients with high-severity illnesses care more about professional attire in the stage of decision making. These findings contribute to the domain knowledge of online service design and delivery, especially in the arena of online health services

Admittance Control of Four-link Bionic Knee Exoskeleton with Inertia Compensation

This paper proposes a control algorithm based on the admittance principle for the motion of the four-link bionic knee exoskeleton. Firstly, the interaction between the operator and the exoskeleton was converted into the desired trajectory of the exoskeleton. Then, the inertia compensation is achieved in light of the admittance features of exoskeleton movement. Finally, the validity of the admittance control method for four-link bionic knee was confirmed through simulation experiment. The simulation results show that the relative error of the joint angle between the operator and the exoskeleton was less than 5% at normal swinging frequency, and the interaction force between the manipulator and the exoskeleton was within ±0.5 N. The research findings lay a theoretical basis for practical application of exoskeletons

Vortex Sheet Simulations of 3D Flows Using an Adaptive Triangular Panel/Particle Method.

In this thesis we present an accurate and efficient algorithm for computing ideal flows using vortex sheets. A vortex sheet is a mathematical model simulating slightly viscous flow in which the vorticity is concentrated on a surface and the viscous effects are small. The sheet surface is represented by a set of triangular panels and each panel contains a set of active and passive Lagrangian particles. The active particles carry vorticity and the passive particles are used for panel subdivision and particle insertion. The method computes the vorticity carried by those particles, and then the induced velocities are computed with a tree-code. As the sheet surface evolves, stretching and twisting occur, hence refinement is needed to maintain resolution. The quadrature and the refinement procedure are local in the sense that they only use information within each panel. The purpose of implementing the locality is to avoid taking derivatives of the flow map, which is difficult because the derivatives grow in amplitude as time progresses. Computations of homogeneous flow, in which vorticity is conserved, are presented. We also present results for slightly stratified flow, in which vorticity is generated baroclinically on the sheet.Ph.D.MathematicsUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/55669/2/hualongf_1.pd