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Search Results: 1 - 10 of 12491 matches for " Shu Pengcheng "
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Research on a Scroll Expander Used for Recovering Work in a Fuel Cell
Gao Xiaojun,Li Liansheng,Zhao Yuanyang,Shu Pengcheng
International Journal of Thermodynamics , 2004, DOI: 10.5541/ijot.120
Abstract: The energy of the exhausted high-pressure air from a proton exchange membrane (PEM) fuel cell can still be recovered. The performance of the scroll expander used for recovering this energy is studied in this paper. A numerical simulation of the expander is presented, and then the simulated results are compared with that of the experiment results gleaned from the prototype of the expander. The matching of the flows and pressure characteristics between the compressor-expander (C-E) is also discussed. Finally, this paper points out that leakage has a significant effect on the volumetric efficiency, the quantity of recovered work, and other performance indicators of the scroll expander. The matching of the C-E is a key factor in the practical application of this system.
The Modification of the Valves of a Refrigeration Piston Compressor due to the Refrigerant Change
Zhao Yuanyang,Li Liansheng,Guo Bei,Shu Pengcheng
International Journal of Thermodynamics , 2003, DOI: 10.5541/ijot.105
Abstract: Compressor and refrigerant play key roles in a refrigeration system. Owing to the de-mands of environment protection, the CFCs and HCFCs refrigerants will be phased out in a short time, and new refrigerants such as R600, R134a and R407C will be used. As the new refrigerant is selected, the motion regularity of the valves will be changed. The motion regularity of the ring valves of a 2-stage refrigerating piston compressor is simulated, and the calculations are done respectively with refrigerants R717 (ammonia), R22 and R134a. The results show that refrigerants and working conditions of a compressor have a direct effect on the motion of the ring valves. Comparing the original design parameters of the ring valves with the modified ones, the former are effective for the HCFC refrigerants, the latter have perfect motion of the valves for the new refrigerants, and the refrigeration system performance parameters, such as input power, the refrigerating quantity and the COP value, are also better. Service life test of the compressor system using the ring valves has been done for R717. The compressor using the modified ring valves has a life exceeding 8000 hours. Hence, the valve design should consider the influences of the refrigerant.
Effects of Calcination Temperatures on Photocatalytic Activity of Ordered Titanate Nanoribbon/SnO2 Films Fabricated during an EPD Process
Li Zhao,Jingrun Ran,Zhan Shu,Guotian Dai,Pengcheng Zhai,Shimin Wang
International Journal of Photoenergy , 2012, DOI: 10.1155/2012/472958
Abstract: Ordered titanate nanoribbon (TNR)/SnO2 films were fabricated by electrophoretic deposition (EPD) process using hydrothermally prepared titanate nanoribbon as a precursor. The formation mechanism of ordered TNR film on the fluorine-doped SnO2 coated (FTO) glass was investigated by scanning electron microscopy (SEM). The effects of calcination temperatures on the phase structure and photocatalytic activity of ordered TNR/SnO2 films were investigated and discussed. The X-ray diffraction (XRD) results indicate that the phase transformation of titanate to anatase occurs at 400°C and with increasing calcination temperature, the crystallization of anatase increases. At 600°C, the nanoribbon morphology still hold and the TiO2/SnO2 film exhibits the highest photocatalytic activity due to the good crystallization, unique morphology, and efficient photogenerated charge carriers separation and transfer at the interface of TiO2 and SnO2.
Grand Challenges in Synthetic Biology to be Accomplished
Pengcheng Fu
Frontiers in Bioengineering and Biotechnology , 2013, DOI: 10.3389/fbioe.2013.00002
Antiferromagnetic order and spin dynamics in iron-based superconductors
Pengcheng Dai
Physics , 2015, DOI: 10.1103/RevModPhys.87.855
Abstract: High-transition temperature (high-$T_c$) superconductivity in the iron pnictides/chalcogenides emerges from the suppression of the static antiferromagnetic order in their parent compounds, similar to copper oxides superconductors. This raises a fundamental question concerning the role of magnetism in the superconductivity of these materials. Neutron scattering, a powerful probe to study the magnetic order and spin dynamics, plays an essential role in determining the relationship between magnetism and superconductivity in high-$T_c$ superconductors. The rapid development of modern neutron time-of-flight spectrometers allows a direct determination of the spin dynamical properties of iron-based superconductors throughout the entire Brillouin zone. In this review, we present an overview of the neutron scattering results on iron-based superconductors, focusing on the evolution of spin excitation spectra as a function of electron/hole-doping and isoelectronic substitution. We compare spin dynamical properties of iron-based superconductors with those of copper oxide and heavy fermion superconductors, and discuss the common features of spin excitations in these three families of unconventional superconductors and their relationship with superconductivity.
Optimization of Spatial Dose Distribution for Controlling Sidewall Shape in Electron-beam Lithography
Pengcheng Li
Physics , 2015,
Abstract: Electron-beam (e-beam) lithography is widely employed in fabrication of 2-D patterns and 3-D structures. A certain type or shape of the sidewall in the remaining resist profile may be desired in an application, e.g., an undercut for lift-off and a vertical sidewall for etching, or required for a device. Also, as the feature size is decreased well below a micron, a small variation of the sidewall slope can lead to a significant (relative) CD error in certain layers of resist. Therefore, it is important to understand effects of spatial dose distribution on sidewall shape and be able to achieve the desired shape. In this study, via simulation, the relationship among the total dose, spatial distribution of dose, developing time and sidewall shape, and performance of the method developed to optimize the dose distribution for a target sidewall shape have been analyzed. The simulation results have been verified through experiments.
A Review of Proximity Effect Correction in Electron-beam Lithography
Pengcheng Li
Physics , 2015,
Abstract: I review the work of proximity effect correction (PEC) in electron-beam (e-beam) lithography with emphasis on dose modification and shape modification PEC techniques.
A Hybrid Key Management Scheme Based on Clustered Wireless Sensor Networks  [PDF]
Pengcheng Zhao, Yong Xu, Min Nan
Wireless Sensor Network (WSN) , 2012, DOI: 10.4236/wsn.2012.48029
Abstract: According to the weakness of session key construction based on node’s own location, we propose a hybrid key management scheme which based on clustered wireless sensor networks. The use of hierarchical thinking, reducing the amount of key storage and computing, while supporting network topology, dynamic key management for which aims to prevent leakage. Through analyzing, it shows that the scheme have certain advantages in key connectivity, security, communication and energy consumption.
An Unusual Life-Threatening Hemobilia Caused by Hepatic Pseudoaneurysm Following Choledochostomy: A Case Report  [PDF]
Zijun Liu, Shiyong Yang, Pengcheng Xi
Case Reports in Clinical Medicine (CRCM) , 2016, DOI: 10.4236/crcm.2016.52007
Abstract: The present report describes a case of hemobilia caused by hepatic pseudoaneurysm. A 63-year-old woman was admitted with abdominal pain and mild jaundice. She was diagnosed as choledocholithiasis and hypersplenism and underwent choledocolithotomy and splenectomy. 9th day post operation, massive fresh blood suddenly flew out from T tube and she underwent emergency abdominal exploration but there were no obvious bleeding sites in the abdominal cavity and no bleeding sites in the biliary tree by choledochoscope. 7th day after the second operation, fresh blood suddenly flew out from T tube again and angiography showed two small peudoaneurysms at the second branch of right hepatic artery which might result in hemobilia. The hemobilia was treated successfully with coil embolisation of peudoaneurysms and she recovers fully.
Composition operators from the Bloch space into the spaces
Pengcheng Wu,Hasi Wulan
International Journal of Mathematics and Mathematical Sciences , 2003, DOI: 10.1155/s0161171203207122
Abstract: Suppose that φ(z) is an analytic self-map of the unit disk Δ. We consider the boundedness of the composition operator Cφ from Bloch space ℬ into the spaces QT (QT,0) defined by a nonnegative, nondecreasing function T(r) on 0≤r<∞.
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