0:17:04
-
A classical approach to the modeling of quantum mass（2）
- 2014 Spring World Congress on Engineering and Technology (SCET 2014)——This work focused on one question: Where does the rest mass of a particle come from? In modern physics, a particle is regarded as the quantum excitation of a field. Then, how can a particle have a rest mass? According to the Standard Model, a particle acquires mass through its interaction with a hypothetical Higgs field. The rest mass is essentially identified from the Klein- Gordon equation of a free particle (through its associated Lagrangian density). It was reported recently that a key feature of this theory (i.e., prediction of Higgs boson) is supported by experiments conducted at LHC. Nevertheless, there are still many questions about the Higgs model. Particularly, the physical meaning of the rest mass m based on the Higgs mechanism would be intrinsically different from energy E or momentum p. This does not seem to be very satisfactory. In this paper, we would like to explore a different approach based on more classical concepts. We think mass should be treated on the same footing as momentum and energy, and the definition of mass should be strictly based on its association with the momentum. By postulating that all particles in nature (including fermions and bosons) are excitation waves of the vacuum medium, we propose a simple wave equation for a free particle. We find that the rest mass of the particle is associated with a “transverse wave number”, and the Klein-Gordon equation can be derived from the general wave equation if one considers only the longitudinal component of the excitation wave. Implications of this model and its comparison with the Higgs model are discussed in this work.
- 关键字:粒子静止质量 希格斯场 自由粒子 量子质量 激发波长
0:14:53
-
A classical approach to the modeling of quantum mass（3）
- 2014 Spring World Congress on Engineering and Technology (SCET 2014)——This work focused on one question: Where does the rest mass of a particle come from? In modern physics, a particle is regarded as the quantum excitation of a field. Then, how can a particle have a rest mass? According to the Standard Model, a particle acquires mass through its interaction with a hypothetical Higgs field. The rest mass is essentially identified from the Klein- Gordon equation of a free particle (through its associated Lagrangian density). It was reported recently that a key feature of this theory (i.e., prediction of Higgs boson) is supported by experiments conducted at LHC. Nevertheless, there are still many questions about the Higgs model. Particularly, the physical meaning of the rest mass m based on the Higgs mechanism would be intrinsically different from energy E or momentum p. This does not seem to be very satisfactory. In this paper, we would like to explore a different approach based on more classical concepts. We think mass should be treated on the same footing as momentum and energy, and the definition of mass should be strictly based on its association with the momentum. By postulating that all particles in nature (including fermions and bosons) are excitation waves of the vacuum medium, we propose a simple wave equation for a free particle. We find that the rest mass of the particle is associated with a “transverse wave number”, and the Klein-Gordon equation can be derived from the general wave equation if one considers only the longitudinal component of the excitation wave. Implications of this model and its comparison with the Higgs model are discussed in this work.
- 关键字:粒子静止质量 希格斯场 自由粒子 量子质量 激发波长
0:15:23
-
Thermally-Assisted-Occupation Density Functional Theory（1）
- 2014 Spring World Congress on Engineering and Technology (SCET 2014)——In this talk, I will briefly describe the formulation of our recently proposed thermally-assisted-occupation density func-tional theory (TAO-DFT) [J.-D. Chai, J. Chem. Phys. 136, 154104 (2012)] and the density functional approximations to TAO-DFT [J.-D. Chai, J. Chem. Phys. 140, 18A521 (2014)]. In contrast to Kohn-Sham DFT, TAO-DFT is a DFT with fractional orbital occupations given by the Fermi-Dirac distribution (controlled by a fictitious temperature), for the study of large ground-state systems with strong static correlation effects. Relative to TAO-LDA (i.e., the local density approximation to TAO-DFT), TAO-GGAs (i.e., the generalized-gradient approximations to TAO-DFT) are significantly superior for a wide range of applications, such as thermochemistry, kinetics, and reaction energies. For noncovalent interactions, TAO-GGAs with empirical dispersion corrections are shown to yield excellent performance. Due to their computational efficiency for systems with strong static correlation effects, TAO-LDA and TAO-GGAs are applied to study the elec-tronic properties of acenes with different number of linearly fused benzene rings (up to 100), which is very challenging for conventional electronic structure methods. Some interesting results will be presented in this talk.
- 关键字:密度泛函理论 静态关联效应系统 热化学 动力学
0:18:34
-
Thermally-Assisted-Occupation Density Functional Theory（2）
- 2014 Spring World Congress on Engineering and Technology (SCET 2014)——In this talk, I will briefly describe the formulation of our recently proposed thermally-assisted-occupation density func-tional theory (TAO-DFT) [J.-D. Chai, J. Chem. Phys. 136, 154104 (2012)] and the density functional approximations to TAO-DFT [J.-D. Chai, J. Chem. Phys. 140, 18A521 (2014)]. In contrast to Kohn-Sham DFT, TAO-DFT is a DFT with fractional orbital occupations given by the Fermi-Dirac distribution (controlled by a fictitious temperature), for the study of large ground-state systems with strong static correlation effects. Relative to TAO-LDA (i.e., the local density approximation to TAO-DFT), TAO-GGAs (i.e., the generalized-gradient approximations to TAO-DFT) are significantly superior for a wide range of applications, such as thermochemistry, kinetics, and reaction energies. For noncovalent interactions, TAO-GGAs with empirical dispersion corrections are shown to yield excellent performance. Due to their computational efficiency for systems with strong static correlation effects, TAO-LDA and TAO-GGAs are applied to study the elec-tronic properties of acenes with different number of linearly fused benzene rings (up to 100), which is very challenging for conventional electronic structure methods. Some interesting results will be presented in this talk.
- 关键字:密度泛函理论 静态关联效应系统 热化学 动力学
0:14:05
-
Ohmic heating for tofu making - a pilot study
- 2014 Spring World Congress on Engineering and Technology (SCET 2014)——The aim of this study is to explore the relationship between temperature and electrical conductivity of soya milk under ohmic heating in tofu making. The soya milk of 10°Brix was heated to a steady temperature of 90°C. The applied voltage was increased and the temperature rising rate was investigated for adequate heating profiles in tofu making. Experimental results showed that the electrical conductivity of soya milk is proportional to the heating time. The temperature rising rate was increased from 1.46 to 3.82 °C/min as a result of increased voltage. Hence ohmic heating could be an efficient, convenient heating measure in tofu making.
- 关键字:豆腐制作温度 豆浆电导率 奥姆加热 升温速率
0:15:07
-
The Power Transmission Technique for Hybrid Electric Vehicles（1）
- The 6th Asia-Pacific Power and Energy Engineering Conference (APPEEC 2014)——To solve the problem of energy crisis and environmental pollution, electric vehicle is considered as one of the essential solutions. There are mainly three types of electric vehicles: battery electric vehicles, hybrid electric vehicles, and fuel cell electric vehicles. With the technology of batteries considered, hybrid electric vehicles are more realistic. There are three kinds of hybrid electric vehicles: series, parallel, and series-parallel hybrid electric vehicles. The topologies and features of different hybrid electric vehicles are introduced. A kind of series-parallel hybrid electric vehicle, which is called compound-structure permanent-magnet synchronous machine (CS-PMSM), is discussed deeply.
- 关键字:电池电动汽车 混合动力电动汽车 燃料电池电动汽车 能源危机 环境污染
0:16:25
-
The Power Transmission Technique for Hybrid Electric Vehicles（2）
- The 6th Asia-Pacific Power and Energy Engineering Conference (APPEEC 2014)——To solve the problem of energy crisis and environmental pollution, electric vehicle is considered as one of the essential solutions. There are mainly three types of electric vehicles: battery electric vehicles, hybrid electric vehicles, and fuel cell electric vehicles. With the technology of batteries considered, hybrid electric vehicles are more realistic. There are three kinds of hybrid electric vehicles: series, parallel, and series-parallel hybrid electric vehicles. The topologies and features of different hybrid electric vehicles are introduced. A kind of series-parallel hybrid electric vehicle, which is called compound-structure permanent-magnet synchronous machine (CS-PMSM), is discussed deeply.
- 关键字:电池电动汽车 混合动力电动汽车 燃料电池电动汽车 能源危机 环境污染
0:15:32
-
Behavior of HAWT with differential planetary gearbox
- The 6th Asia-Pacific Power and Energy Engineering Conference (APPEEC 2014)——A dynamic model for simulating behavior of a horizontal axis wind turbine (HAWT) with differential planetary gearbox is developed. The aerodynamic load applied to the wind turbine connected with the carrier is described using the quasi-steady approach. The control torque is assumed to be applied to the external ring of the gearbox. Steady regimes of the device are analyzed, and their stability is studied. For the case of constant control torque, power costs are esti-mated required for preserving constant angular speed of the generator.
- 关键字:风力涡轮机 电力成本 动态模型 差动行星齿轮箱 水平轴风力机
0:19:20
-
Behaviour of Couple Stress Fluids in Porous Annular Squeeze Films
- The 5th ENGII Conference——The laminar squeeze flow of an incompressible couple stress fluid between porous annular disks is studied using hydrodynamic lubrication theory. The modified Reynolds' equation is derived using Stokes microcontinuum theory and is solved analytically. Analytical expressions for the squeeze film pressure and the load carrying capacity are obtained in terms of Fourier-Bessel series. Numerical results are obtained for the sinusoidal motion of the upper disk. The effect of couple stresses and that of porous facing on the squeeze film behaviour are analysed through the squeeze film pressure and the load carrying capacity. Further, the equation for the gap width between the disks is obtained from the inverse problem.
- 关键字:应力偶流体 多孔环形紧缩膜 流体动力 雷诺方程
0:14:58
-
Linear Instability of the Supersonic Boundary Layer on a Compliant Surface
- The 5th ENGII Conference——In the paper the influence of flexible covering properties on the linear development of disturbances in a supersonic boundary layer is investigated for Mach numbers M = 1.0, 2.0, 5.3, 6.0. As a model of a covering the porous plate closed by a flexible film is used. In the absence of gas in pores it is established that the flexible covering stabilizes boundary layer in the area of large Reynolds numbers and destabilizes it at small Reynolds numbers. Joint influence of the thickness and tension of a film leads to an appearance of additional unstable waves. For filled with gas pores the researches are conducted as taking into account losses of energy of disturbances in pores and in their absence. Calculations without power losses indicate possibility of existence of an absolute instability of the boundary layer on the flexible surface. The damping properties of a flexible covering connected with power losses in pores reduce their stabilizing role.
- 关键字:超音速边界层 兼容表面 线性不稳定性