Pb2+ doped Cd0.2Zn0.8S and Cd0.8Zn0.2S were prepared with coprecipitation method. The results indicate that the valence band of Cd0.2Zn0.8S solid solution with wide band gap is heightened by the Pb 6s level hybridizat...
详细信息
Pb2+ doped Cd0.2Zn0.8S and Cd0.8Zn0.2S were prepared with coprecipitation method. The results indicate that the valence band of Cd0.2Zn0.8S solid solution with wide band gap is heightened by the Pb 6s level hybridization with valence band, and the photocatalytical hydrogen evolution ability is improved. When Pb2+ is doped in Cd0.8Zn0.2S solid solution with narrow band gap, it acts as a recombination center and is unable to improve water splitting activity of the catalyst. So the doping of Pb2+ is effective only for the semiconductor with wide band gap.
The numerical simulation technique was employed to study the flow and heat transfer performance of the rotating cooling channel with feed chamber and impingement chamber. The discharge coefficient of the impingement h...
详细信息
The numerical simulation technique was employed to study the flow and heat transfer performance of the rotating cooling channel with feed chamber and impingement chamber. The discharge coefficient of the impingement holes and the average Nusselt number of the impingement target surface in the blade leading edge in rotating were obtained. The result shows that the Coriolis force induced by the rotation effect can change the discharge coefficient of the impingement holes. With the increase of the rotating speed, the Coriolis force effect becomes more obvious. The discharge coefficient increases with the increase of rotating Reynolds number and outflow ratio, and decreases with the increase of the inlet Reynolds number. The influence of the rotation on the average Nusselt number of the impingement target surface is not obvious. With the increase of the rotating speed, Nusselt number increases slightly only at high rotating speed.
The processing of interference fringe is the most important step in holographic interferometric technique. The interference fringe of mass diffusion were gathered and proposed, and 3 key steps in the process which red...
详细信息
The processing of interference fringe is the most important step in holographic interferometric technique. The interference fringe of mass diffusion were gathered and proposed, and 3 key steps in the process which reduce the precision mostly were improved in this paper. The improvements include the following steps: wavelet de-noise, frequency-domain wave filtering, phase unwrapping. The categories of noise were analyzed and some specific methods were used to reduce the noise. The improvements increased the precision greatly, and established a solid foundation for the using of laser holographic interferometric technique.
Based on the investigations on the influences of geometrical parameters and symmetrical plates disposal scheme on DMFC performance, a new scheme that staggered channels arrangement was presented and studied in this wo...
详细信息
Based on the investigations on the influences of geometrical parameters and symmetrical plates disposal scheme on DMFC performance, a new scheme that staggered channels arrangement was presented and studied in this work. The characteristics of fluid flow, proton transport and reaction rate distribution were well studied and contrasted to symmetrical scheme used in a cell unit. The effects of thickness of catalyst layer, backing layer and membrane on cell local average current density were investigated. After optimized design, a staggered scheme was put forward, and the higher potential output and greater limiting current density were obtained compared to the conventional symmetrical scheme. A new way to optimizing DMFC design and assembly was put forward.
In this paper, the statues and development trends of combustion research in internal combustion engines are discussed from several aspects. Some key issues in combustion of internal combustion engines are raised. The ...
详细信息
In this paper, the statues and development trends of combustion research in internal combustion engines are discussed from several aspects. Some key issues in combustion of internal combustion engines are raised. The combustion in internal combustion engines is a complex process with chemical reaction and energy conversion and there are still many aspects needed to be clarified, especially the chemical reaction mechanism and soot formation. Meanwhile, combustion diagnostic is playing an increasing role in the understanding of combustion. The motivation to deepen the research is the continuous requirement of high-efficiency and low-emission engines. Remarkable progress has been achieved in developing low-emission combustion concept like HCCI and low-temperature combustion. Alternative fuel engines become an important aspect in engine research and development. Advanced combustion technology combined with fuel control technology and after-treatment can realize the high-efficient and low-emission target.
A two-dimensional, steady-state model of a direct methanol fuel cell (DMFC) with liquid methanol feed was developed. The electrode kinetics, multi-component transport and methanol crossover phenomenon were all conside...
详细信息
A two-dimensional, steady-state model of a direct methanol fuel cell (DMFC) with liquid methanol feed was developed. The electrode kinetics, multi-component transport and methanol crossover phenomenon were all considered. The effect of channels disposal density, the influence of backing layer, catalyst layer and polymer electrolyte membrane thickness on mass transfer and cell performance was investigated. The results showed that: with the increase of channels disposal density and the increase of catalyst layer thickness, the equality of reaction rate and cell performance will elevated. The sizes of catalyst layer and membrane effect farthest, the correspondingly optimized work can increase the average current density about 131.0% and 17.8%. There are moderate optimal thickness sizes of backing layer and membrane, and the sizes should be chosen after thinking about the sizes of flow field plate and MEA.
Now LiCoO2 is the most widely used electrode material in commercial rechargeable lithium-based batteries; however, the toxicity of cobalt and the scarcity of cobalt sources, as well as the limited charge/discharge cap...
详细信息
Now LiCoO2 is the most widely used electrode material in commercial rechargeable lithium-based batteries; however, the toxicity of cobalt and the scarcity of cobalt sources, as well as the limited charge/discharge capacity（130-140 mA.h.g-1） of LiCoO2 electrode drive many efforts to develop various alternative electrode materials, including diverse transition metal oxides and their lithiated counterparts. Amongst them, iron oxides,
In this paper, an experimental system for the measurement of mass diffusion coefficient using Michelson laser holographic Interferometry was designed and constructed. The experimental system include: the subsystem of ...
详细信息
In this paper, an experimental system for the measurement of mass diffusion coefficient using Michelson laser holographic Interferometry was designed and constructed. The experimental system include: the subsystem of Michelson interferometer, the diffusion cell for the mass diffusion of liquid-liquid, the subsystem of thermostatic water bath, the subsystem of image collecting and image processing. The mass diffusion coefficients of 0.33 molL-1 KCI solution with water at the temperature of 289.15 K were measured, and the result shows that the average of relative deviations is 1.30% compared with the literature values, and it verified the accuracy and reliability of the system. The mass diffusion coefficients of 0.1 molL-1 saccharose with water at 5 different temperature were measured, and the result shows that the biggest relative deviations is within 5% which verified the reliability of the system further.
暂无评论