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Zhu G.,Wuhan Institute of Marine Electrical Propulsion | Chen D.,Wuhan Institute of Marine Electrical Propulsion
Journal of Materials Science: Materials in Electronics | Year: 2012

Conventional polyol synthesis has been widely used for the preparation of silver nanostructures with different morphologies. However, there is a drawback that it is difficult to control the reaction parameters for shapecontrolled synthesis of silver nanostructures, such as the rate of the addition of silver ions to the solution. In this paper, we combine polyol process and solvothermal method for easily synthesizing silver nanostructures. Importantly, the introduction of cuprous chloride (CuCl) to the reaction leads to increasing the population of twinned Ag seeds (required for wire growth) at the expense of that of single Ag seeds. Silver nanowires (Ag NWs) with uniform width (∼80 nm in width) can be obtained in the presence of poly(vinyl pyrrolidone) (PVP). Some other parameters, such as the reaction temperature and molar ratios of the repeating unit of PVP to AgNO3 (R), also have been discussed. A possible mechanism is put forward to understand the evolution of silver nanostructures. © Springer Science+Business Media, LLC 2012.


Huang F.-Y.,Wuhan University of Technology | Zhou Y.,Wuhan Institute of Marine Electrical Propulsion
Reneng Dongli Gongcheng/Journal of Engineering for Thermal Energy and Power | Year: 2016

In the process of building LNG ship, the welding residual stress not only can induce the cracks of LNG Tanks, but also can change the loading capacity of LNG Tanks when superimposed upon applied pressure. In order to obtaining mechanical behavior of welding process, it is necessary to analyze the welding residual stresses of LNG Tanks with finite element method. Using axisymmetric model and Live-dead Element, this study aims to investigate the distributions of the welding residual stresses in a LNG Tanks Used in LNG Carrier. According to the national standard, the effect of the LNG tank groove size on residual stress distribution was studied, and the effect of heat treatment to welding residual Mises stress was also discussed. The results indicate that with the increase of the groove depth, the welding residual Mises stress first decreases and then increases, and reaches the minimum when the groove depth is 6mm. Compared to the V and U type groove angles, groove depth has more significant influence on welding residual Mises stress. In order to reduce the welding residual Mises stress, it is suggested to choose a small groove depth and groove angle according to the actual structure and technology. The heat treatment can also reduce the residual Mises stress by 21%. These results provide a theoretical reference regarding the control of the welding residual stresses in the LNG tanks. © 2016, Editorial Department of "Journal of Engineering for Thermal Energy and Power". All right reserved.


Zhang Z.-Y.,Wuhan Institute of Marine Electrical Propulsion | Yu T.-Y.,Wuhan Foreign Languages School
Wuhan Ligong Daxue Xuebao/Journal of Wuhan University of Technology | Year: 2016

As one of the important equipment in the electric propulsion system, auxiliary acquisition module plays a key role in improving real-time monitoring and reducing the external hard-wired. This paper focused on the design of a set of auxiliary acquisition module based on ARM Microcontroller, which is STM32 family microcontrollers based on the Cortex-M3 core. Through reasonable hardware circuit module and the software design, the auxiliary acquisition module achieved the design specifications, with high reliability, multi-signal conversion, multiple network interfaces, miniaturization, modular, and low cost. The successful development of the device, will greatly promote the ship cabin automation level, which is meaningful in fault monitoring and fault analysis to the auto operation system of the ship. © 2016, Wuhan University of Technology. All right reserved.


Zhang Y.,Wuhan University | Zhang Y.,China Three Gorges University | Ruan J.,Wuhan University | Huang T.,Wuhan University | And 3 more authors.
IEEE Transactions on Magnetics | Year: 2012

This paper investigates a 3-D coupled-field finite-element method (FEM) used in simulation of temperature distributions in air-cooled asynchronous induction motors. The temperature rise in motors is due to Joule's losses in stator windings and squirrel cages, and heat dissipation by air convection and solid conduction. The Joule's losses calculated by 3-D eddy-current field analysis are used as the input for the thermal field analysis, which is deeply dependent on accurate air fluid field analysis. Moreover, a novel multi-component fluid model is proposed to deal with the influence of rotor rotation upon the air convection. A test prototype is designed and manufactured. The good agreement of the temperature distributions between the simulated and measured results validates the proposed methodology. © 2012 IEEE.


Chen Y.-H.,Wuhan Institute of Marine Electrical Propulsion | Ding T.-H.,Wuhan Institute of Marine Electrical Propulsion | Tian L.,Wuhan Institute of Marine Electrical Propulsion
Dianji yu Kongzhi Xuebao/Electric Machines and Control | Year: 2014

In view of the shortcomings in the traditional vibration characteristics simulation methods, like setting material property parameters monolithically, simple equivalent as a whole, and so on, in order to improve the accuracy of the simulation results of vibration characteristics of large motor's laminated core, and also to provide important reference data for the motor design, this paper proposes a reformative simulation method of motor pole core vibration characteristics. The pole core was considered as a homogeneous orthotropic laminates structure material, and material property parameters were obtained by fitting curve recommended. Windings material properties were set apart, and the overall equivalent measures of dipping lacquer was talent. Then the simulation model was established, the vibration characteristics of core was simulated and analyzed. Combining with pt modal experiments, the new method validates its veracity and accuracy.


Gong B.,Wuhan Institute of Marine Electrical Propulsion | Cheng S.,Huazhong University of Science and Technology
Lecture Notes in Electrical Engineering | Year: 2016

The neutral point (NP) voltage variation is studied; the relationship between NP voltage variation and the overlap is analyzed, in this paper. And a new SPWM control method for three-level (3L) inverter is proposed. A closed loop system is built by altering the displacement of the carriers in the vertical direction in the proposed method, and the control structure is simple. It is easy to make the NP voltage balance by adjusting the overlap. Simulation results indicate that the proposed method can get a good NP voltage control effect. © Springer-Verlag Berlin Heidelberg 2016.


Li H.,Wuhan Institute of Marine Electrical Propulsion | Xia H.,Wuhan Institute of Marine Electrical Propulsion | Mei Y.,Wuhan Institute of Marine Electrical Propulsion
Desalination | Year: 2016

A combined model is developed for flux decline of reverse osmosis (RO) membranes, which accounts for initial fouling due to adsorption and subsequent fouling due to the growth of a fouling layer. The predicted data are in excellent agreement with the experimental ones obtained over crossflow filtration of organic wastewaters using aromatic polyamide RO membranes over the entire course of the filtration. The model also provides a smooth transition from the adsorption regime to the fouling layer filtration regime. Based on the flux profiles and the analysis of the membrane surface, a two-step fouling mechanism is proposed to describe the evolution of fouling during continuous crossflow operation of RO membranes. © 2016 Elsevier B.V.


Zou L.,CAS Shanghai Advanced Research Institute | Fan J.,Wuhan Institute of Marine Electrical Propulsion | Zhou Y.,CAS Shanghai Advanced Research Institute | Wang C.,CAS Shanghai Advanced Research Institute | And 3 more authors.
Nano Research | Year: 2015

The development of cost-effective oxygen reduction reaction (ORR) catalysts with a high methanol tolerance and enhanced durability is highly desirable for direct methanol fuel cells. This work focuses on the conversion of PtNi nanoparticles from a disordered solid solution to an ordered intermetallic compound. Here the effect of this conversion on ORR activity, durability, and methanol tolerance are characterized. X-ray diffraction and transmission electron microscopy results confirm the formation of ordered PtNi intermetallic nanoparticles with high dispersion and a mean particle size of about 7.6 nm. The PtNi intermetallic nanoparticles exhibited enhanced mass and specific activities toward the methanol-tolerant ORR in pure and methanol-containing electrolytes. The specific activity of the ORR at 0.85 V on the PtNi intermetallic nanoparticles is almost 6 times greater than on commercial Pt/C and 3 times greater than on disordered PtNi alloy. Durability tests indicated a minimal loss of ORR activity for PtNi intermetallic nanoparticles after 5,000 potential cycles, whereas the ORR activity decreased by 28% for disordered PtNi alloy. The enhanced methanoltolerant ORR activity and durability may be attributed to the structural and compositional stabilities of the ordered PtNi intermetallic nanoparticles compared relative to the stabilities of the disordered PtNi alloy, strongly suggesting that the PtNi intermetallic nanoparticles may serve as highly active and durable methanol-tolerant ORR electrocatalysts for practical applications. [Figure not available: see fulltext.] © 2015, Tsinghua University Press and Springer-Verlag Berlin Heidelberg.


Wang Q.-D.,China University of Mining and Technology | Zhang W.,Wuhan Institute of Marine Electrical Propulsion
RSC Advances | Year: 2015

This work reports a systematic ab initio and chemical kinetic study of the rate constants for hydrogen atom abstraction reactions by hydrogen radical on the isomers of unsaturated C6 methyl esters. Geometry optimizations and a frequency calculations of all of the species involved, as well as the hindrance potential descriptions for reactants and transition states have been performed at the B3LYP/6-311G(2d,d,p) level of theory implemented in the composite CBS-QB3 method. The intrinsic reaction coordinate (IRC) calculations are performed to verify that the transition states are the right minima connecting the reactants and the products. The hindered rotor approximation has been used for the low frequency torsional modes in both reactants and transition states. The high-pressure limit rate constants for every reaction channel in certain methyl ester fuel molecules are calculated via conventional transition-state theory with the asymmetric Eckart method for quantum tunneling effect by using the accurate potential energy information obtained with the CBS-QB3 method. The individual rate constants at different reaction sites for all the methyl esters in the temperature range from 500 to 2500 K are calculated and fitted to the modified three parameters Arrhenius expression using least-squares regression. Further, a branching ratio analysis for each reaction site has also been investigated for all of the methyl esters. To the best our knowledge, it is the first systematic theoretical studies to investigate the influence of the double bond on the elementary reaction kinetics of methyl esters. This work not only provides accurate reaction rate coefficients for combustion chemical kinetic modeling, but also helps to gain further insight into the combustion chemistry of biodiesel in future investigations. © The Royal Society of Chemistry 2015.


Gong B.,Wuhan Institute of Marine Electrical Propulsion | Cheng S.,Huazhong University of Science and Technology
Lecture Notes in Electrical Engineering | Year: 2016

The neutral point (NP) voltage fluctuation is an innate problem for NPC three-level (3L) inverter. The NP voltage variation is analyzed, the relationship between NP voltage variation and NP current is studied, and a new control method is proposed in this paper. A closed-loop system is built by superimposing the voltage offset on the regulation phase in the proposed method. It is easy to balance the NP voltage by regulating the value of the voltage offset and the adjusting angle; the control structure is simple. Simulation results verify that the proposed control method has excellent ability to maintain the NP voltage balance. © Springer-Verlag Berlin Heidelberg 2016.

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