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Search Results: 1 - 10 of 380496 matches for " P. C. Pei "
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The Two-Constant Cost Model and the Estimation of the Cost Performance Evolutions of the Proton Exchange Membrane Fuel Cell Power Generation  [PDF]
H. F. Zhang, P. C. Pei
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.52A001

This paper aims at formulization and overview of the cost performance evolutions of proton exchange membrane (PEM) fuel cell power generation along with load and time. For this purpose, electricity-cost ratio (ECR) is proposed as the measuring parameter for the cost performance and a two-constant cost model is proposed to concisely describe the cost characteristic of the power generation as the opposite of a multi-constant cost model. Combination of the two-constant cost model and the ideal cell model developed recently produces an inclusive ECR equation that has three analytical expressions and thus allows of straight overviews of the cost performance evolutions in the working zones of the cells. The applications to real cells confirm the validity of the equation for operation optimization and technique evaluation of PEM fuel cells. And more insights into the cost performance evolutions are inferred by means of the equation to help promote the commercialization of PEM fuel cells.

Discrimination and Estimation of the Maximum Cost Performance of Proton Exchange Membrane Fuel Cell Power Generation with Seven Constants  [PDF]
H. F. Zhang, P. C. Pei
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.52A008

This paper is dedicated to analytical expression of the maximum electricity-cost ratio (M-ECR) point of the proton exchange membrane (PEM) fuel cell power generation as the function of cell constants and cost constants. That is to formulize the maximum cost performance (MCP) magnitude and the optimal final operating (OFO) location in the working zone based on the five-constant ideal cell model and the two-constant cost model. The issues are well resolved by introducing the concepts of economic voltage and cost factor and describing the movement of the M-ECR point with cost factor. According to mathematical derivations, the movement can be described in the form of MCP and OFO curves. The derivations lead to a complete set of discriminants and criteria of the M-ECR point of PEM fuel cells that theoretically cover all of cell specialties and all of cost specialties. The discriminants and criteria may act as a general tool for the operation optimization of a diversity of PEM fuel cells and the economic viability estimation of the power generation.

Density distributions of superheavy nuclei
J. C. Pei,F. R. Xu,P. D. Stevenson
Physics , 2005, DOI: 10.1103/PhysRevC.71.034302
Abstract: We employed the Skyrme-Hartree-Fock model to investigate the density distributions and their dependence on nuclear shapes and isospins in the superheavy mass region. Different Skyrme forces were used for the calculations with a special comparison to the experimental data in $^{208}$Pb. The ground-state deformations, nuclear radii, neutron skin thicknesses and $\alpha$-decay energies were also calculated. Density distributions were discussed with the calculations of single-particle wavefunctions and shell fillings. Calculations show that deformations have considerable effects on the density distributions, with a detailed discussion on the $^{292}$120 nucleus. Earlier predictions of remarkably low central density are not supported when deformation is allowed for.
Generalized Second-Order Thomas-Fermi Method for Superfluid Fermi Systems
J. C. Pei,Na Fei,Y. N. Zhang,P. Schuck
Physics , 2015,
Abstract: Using the $\hbar$-expansion of the Green's function of the Hartree-Fock-Bogoliubov equation, we extend the second-order Thomas-Fermi approximation to generalized superfluid Fermi systems by including density-dependent effective mass and spin-orbit potential. We first implement and examine the full correction terms over different energy intervals of the quasiparticle spectra in calculations of finite nuclei. Final applications of this generalized Thomas-Fermi method are intended for various inhomogeneous superfluid Fermi systems.
Biochemical Effects of Sub-Chronic Administration of Catha edulis (Khat) Crude Extract in Rats
A. Al-Zubairi,P. Ismail,C. Pei Pei,S.I.A. Wahab,A. Rahmat
Research Journal of Pharmacology , 2013,
Abstract: The leaves of khat (Catha edulis) are found to have stimulating and pleasurable effects and are chewed habitually by people of East Africa and Arabian Peninsula. Due to the habitual widespread use of khat in many African countries and the Yemen and in order to investigate the effects of khat on various biochemical parameters, the present study was undertaken to evaluate the sub-chronic (13 weeks) administration of crude khat leaves extract in male Sprague-Dawley rats. Three groups were exposed to 0, 1000 and 2000 mg kg 1 body weight/day for 13 consecutive weeks. Fasting plasma levels of Malondialdehyde (MDA) were reduced (p<0.05) in both treatment groups (27 and 29%, respectively) compared to the control group. In contrast, serum values of total cholesterol and HDL cholesterol were shown to be increased (p<0.05) in the 1000 mg kg 1 body weight treatment group. The plasma MDA reducing effect of khat crude extract administration in rats may be attributed to the long term effects of polyphenolic contents of khat leaves, which have been reported to have antioxidant activity. Analysis of serum liver enzymes, uric acid, albumin, total and prostatic ACP and testosterone revealed no changes in the treatment and control groups. These results suggest that the subchronic administration of catha edulis crude extract has no hepatotoxicity and prostate adverse effects in male rats, but may have antioxidant property due to its phenolic compounds.
Influence of Weight Ratio of Poly(4-vinylphenol) Insulator on Electronic Properties of InGaZnO Thin-Film Transistor
C. J. Chiu,Z. W. Pei,S. P. Chang,S. J. Chang
Journal of Nanomaterials , 2012, DOI: 10.1155/2012/698123
Abstract: Spin-coated organic PVP layers were used as dielectric layers in a-IGZO TFTs. Weight ratios of 20 : 1, 10 : 1, and 5 : 1 for PVP and PMF, a cross-linking agent, were used. The a-IGZO TFTs with the PVP : PMF ratio of 20 : 1 showed a large hysteresis in the - curve and - curve, the hysteresis increases with the increase of hydroxyl groups and also deteriorated the gate leakage current. In contrast, the devices with the PVP : PMF ratio of 5 : 1 dielectric displayed only small hysteresis. According to our experimental results, preventing the possible diffusion of hydroxyl-contained species in polymeric dielectrics is a very important factor in improving the electrical properties of high-performance a-IGZO TFT devices.
Hybridization and amplification rate correction for affymetrix SNP arrays
Quan Wang, Pei C Peng, Min P Qian, Lin Wan, Ming H Deng
BMC Medical Genomics , 2012, DOI: 10.1186/1755-8794-5-24
Abstract: CNVhac first estimates the allelic concentrations (ACs) of target sequences by using the sample independent parameters trained through physicochemical hybridization law. Then the raw CN is estimated by taking the ratio of AC to the corresponding average AC from a reference sample set for one specific site. Finally, a hidden Markov model (HMM) segmentation process is implemented to detect CNV regions.Based on public HapMap data, the results show that CNVhac effectively smoothes the genomic waves and facilitates more accurate raw CN estimates compared to other methods. Moreover, CNVhac alleviates, to a certain extent, the sample dependence of inference and makes CNV calling with appreciable low FDRs.CNVhac is an effective approach to address the common difficulties in SNP array analysis, and the working principles of CNVhac can be easily extended to other platforms.
Global Motion Percept Mediated through Integration of Barber Poles Presented in Bilateral Visual Hemifields
Li-Ting Huang, Alice M. K. Wong, Carl P. C. Chen, Wei-Han Chang, Ju-Wen Cheng, Yu-Ru Lin, Yu-Cheng Pei
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0074032
Abstract: How is motion information that has been obtained through multiple viewing apertures integrated to form a global motion percept? We investigated the mechanisms of motion integration across apertures in two hemifields by presenting gratings through two rectangles (that form the dual barber poles) and recording the perceived direction of motion by human observers. To this end, we presented dual barber poles in conditions with various inter-component distances between the apertures and evaluated the degree to which the hemifield information was integrated by measuring the magnitude of the perceived barber pole illusion. Surprisingly, when the inter-component distance between the two apertures was short, the perceived direction of motion of the dual barber poles was similar to that of a single barber pole formed by the concatenation of the two component barber poles, indicating motion integration is achieved through a simple concatenation mechanism. We then presented dual barber poles in which the motion and contour properties of the two component barber poles differed to characterize the constraints underlying cross-hemifield integration. We found that integration is achieved only when phase, speed, wavelength, temporal frequency, and duty cycle are identical in the two barber poles, but can remain robust when the contrast of the two component barber poles differs substantially. We concluded that a motion stimulus presented in bilateral hemifields tends to be integrated to yield a global percept with a substantial tolerance for spatial distance and contrast difference.
Pinning mode resonance of a Skyrme crystal near Landau level filling factor $ν$=1
Han Zhu,G. Sambandamurthy,Yong P. Chen,Pei-Hsun Jiang,Lloyd Engel,D. C. Tsui,L. N. Pfeiffer,K. W. West
Physics , 2009, DOI: 10.1103/PhysRevLett.104.226801
Abstract: Microwave pinning-mode resonances found around integer quantum Hall effects, are a signature of crystallized quasiparticles or holes. Application of in-plane magnetic field to these crystals, increasing the Zeeman energy, has negligible effect on the resonances just below Landau level filling $\nu=2$, but increases the pinning frequencies near $\nu=1$, particularly for smaller quasiparticle/hole densities. The charge dynamics near $\nu=1$, characteristic of a crystal order, are affected by spin, in a manner consistent with a Skyrme crystal.
UNEDF: Advanced Scientific Computing Transforms the Low-Energy Nuclear Many-Body Problem
M. Stoitsov,H. Nam,W. Nazarewicz,A. Bulgac,G. Hagen,M. Kortelainen,J. C. Pei,K. J. Roche,N. Schunck,I. Thompson,J. P. Vary,S. M. Wild
Physics , 2011,
Abstract: The UNEDF SciDAC collaboration of nuclear theorists, applied mathematicians, and computer scientists is developing a comprehensive description of nuclei and their reactions that delivers maximum predictive power with quantified uncertainties. This paper illustrates significant milestones accomplished by UNEDF through integration of the theoretical approaches, advanced numerical algorithms, and leadership class computational resources.
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