The Experts below are selected from a list of 17883 Experts worldwide ranked by ideXlab platform
Hui Dong - One of the best experts on this subject based on the ideXlab platform.
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achieve higher efficiency at maximum power with finite time quantum otto cycle
Physical Review E, 2019Co-Authors: Jin-fu Chen, Hui DongAbstract:: The optimization of heat engines was intensively explored to achieve higher efficiency while maintaining the output power. However, most investigations were limited to a few finite-time cycles, e.g., the Carnot-like cycle, due to the complexity of the finite-time thermodynamics. In this paper, we propose a class of finite-time engine with quantum Otto cycle, and demonstrate a higher achievable efficiency at maximum power. The current Model can be widely utilized, benefitting from the general C/τ^{2} scaling of extra work for a finite-time adiabatic process with long control time τ. We apply the adiabatic perturbation method to the quantum Piston Model and calculate the efficiency at maximum power, which is validated with an exact solution.
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achieve higher efficiency at maximum power with finite time quantum otto cycle
arXiv: Quantum Physics, 2019Co-Authors: Jin-fu Chen, Hui DongAbstract:The optimization of finite-time thermodynamic heat engines was intensively explored recently, yet limited to few cycles, e.g. finite-time Carnot-like cycle. In this Letter, we supplement a new type of finite-time engine with quantum Otto cycle and show the better performance. The current Model can be widely utilized benefited from the general \mathcal{C}/\tau^{2} scaling of extra work for finite-time adiabatic process with long control time \tau. Such scaling allows analytical optimization of the generic finite-time quantum Otto cycle to surpass the efficiency at maximum power for the Carnot-like engine. We apply the current perturbation method to the quantum Piston Model and calculate the efficiency at maximum power, which is validated with exact solution.
Jin-fu Chen - One of the best experts on this subject based on the ideXlab platform.
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achieve higher efficiency at maximum power with finite time quantum otto cycle
Physical Review E, 2019Co-Authors: Jin-fu Chen, Hui DongAbstract:: The optimization of heat engines was intensively explored to achieve higher efficiency while maintaining the output power. However, most investigations were limited to a few finite-time cycles, e.g., the Carnot-like cycle, due to the complexity of the finite-time thermodynamics. In this paper, we propose a class of finite-time engine with quantum Otto cycle, and demonstrate a higher achievable efficiency at maximum power. The current Model can be widely utilized, benefitting from the general C/τ^{2} scaling of extra work for a finite-time adiabatic process with long control time τ. We apply the adiabatic perturbation method to the quantum Piston Model and calculate the efficiency at maximum power, which is validated with an exact solution.
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achieve higher efficiency at maximum power with finite time quantum otto cycle
arXiv: Quantum Physics, 2019Co-Authors: Jin-fu Chen, Hui DongAbstract:The optimization of finite-time thermodynamic heat engines was intensively explored recently, yet limited to few cycles, e.g. finite-time Carnot-like cycle. In this Letter, we supplement a new type of finite-time engine with quantum Otto cycle and show the better performance. The current Model can be widely utilized benefited from the general \mathcal{C}/\tau^{2} scaling of extra work for finite-time adiabatic process with long control time \tau. Such scaling allows analytical optimization of the generic finite-time quantum Otto cycle to surpass the efficiency at maximum power for the Carnot-like engine. We apply the current perturbation method to the quantum Piston Model and calculate the efficiency at maximum power, which is validated with exact solution.
I V Nemtchinov - One of the best experts on this subject based on the ideXlab platform.
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bolides produced by impacts of large meteoroids into the earth s atmosphere comparison of theory with observations ii benesov bolide spectra
Astronomy and Astrophysics, 1998Co-Authors: Jiři Borovicka, O P Popova, A P Golub, I B Kosarev, I V NemtchinovAbstract:The unique observational spectrum of the very bright Benesov bolide EN 070591 is compared to theoretical bolide spectra. The −19.5 mag bolide was induced by a meteoroid of an estimated initial mass of 4000 kg, a density of 2 g cm−3 and a kinetic energy of1012 J (0.2 kT TNT). The ablating Piston Model predicts spectra of large bolides by radiative hydrodynamics calculations. We present examples of the calculated H-chondrite vapor spectral opacities and of the resulting spectra for various parameters. Both theoretical and observed spectra show that bolide radiation is composed of atomic line emissions, molecular bands and continuum radiation. The role of the continuum increases with increasing meteoroid size and with decreasing altitude. The atomic lines are produced under the effective excitation temperature of 4000–6000 K. The lines of Fe i are too faint and the lines of Ca i are too bright in the Model in comparison with the observations. Also the computed continuum level is too high. These differences can be explained by the fact that the vapors occupy a larger volume and have lower density than predicted. This is probably a consequence of a mutual interaction of fragments after the meteoroid fragmentation and of a not well understood ablation process. Other differences between the theory and the observation are described and possible Model improvements are discussed.
Z Stojanovic - One of the best experts on this subject based on the ideXlab platform.
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theory of photoacoustic effect in media with thermal memory
Journal of Applied Physics, 2014Co-Authors: S Galovic, Zlatan Soskic, M Popovic, Dalibor Cevizovic, Z StojanovicAbstract:This paper presents a Model for indirect photoacoustic response that includes thermal memory effects. At low frequencies, the Model reduces to the well-known thermal Piston Model of photoacoustic response given by Rosencweig and Gersho. However, at high frequencies, the presented Model predicts resonant behavior of amplitudes and phases of photoacoustic response and determines the respective resonant frequencies. The results of the presented Model enable experimental determination of standard thermal properties of solids (thermal diffusivity and thermal conductivity), as well as thermal memory properties, thermal relaxation time, and heat propagation speed.
Xinwei Wang - One of the best experts on this subject based on the ideXlab platform.
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generalized theory of the photoacoustic effect in a multilayer material
Journal of Applied Physics, 1999Co-Authors: Xinwei WangAbstract:In this work, a generalized expression of the photoacoustic (PA) effect in a multilayer material is derived. This expression takes thermal and optical properties and geometry of a multilayer structure, as well as the thermal contact resistances between layers into consideration. In addition, a composite Piston Model consisting of a thermal Piston and a mechanical Piston of the PA effect is developed and interpreted from the viewpoint of thermodynamics. Mistakes occurring in the thermal Piston Model and in the composite Piston Model developed before are pointed out and corrected. It is also shown that the PA effect has an isochoric character for the thermal Piston and a polytropic character with a polytropic factor of (2−1/γ) for the mechanical Piston. The theory developed in this work is in good agreement with the experimental results, and is applicable to a wide range of photoacoustic problems.
