Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99


Any time

2019 ( 91 )

2018 ( 659 )

2017 ( 639 )

2016 ( 563 )

Custom range...

Search Results: 1 - 10 of 37138 matches for " Pengcheng Zhao "
All listed articles are free for downloading (OA Articles)
Page 1 /37138
Display every page Item
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.
Analysis of Reflection Properties of High Power Microwave Propagation in Mixture-Atmosphere  [PDF]
Tao Tang, Cheng Liao, Qingmin Gao, Pengcheng Zhao
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2010, DOI: 10.4236/jemaa.2010.29070
Abstract: A simple theoretical modeling is made to describe the reflection features of the high power microwave (HPM) in the mixture-atmosphere. The time-space dependent mixture-atmosphere is generated by ionization of the neutral molecules in atmosphere. Reflection will occur when HPM propagates in such mixture-atmosphere. The reflection characteristic of the HPM propagation in the mixture-atmosphere is investigated by FDTD numerical experiments in inhomogeneous medium, the influence on the reflection for different HPM parameters is concluded. An additional stability conditions for the FDTD difference scheme of the HPM mixture-atmosphere propagation model are presented.
Experimental Investigation of Boundary Layer Characteristics on Blade Surface under Different Inlet Flow Conditions  [PDF]
Xiangfeng Bo, Bo Liu, Pengcheng Zhao, Zhiyuan Cao
Energy and Power Engineering (EPE) , 2010, DOI: 10.4236/epe.2010.24044
Abstract: In this paper, an experimental study is conducted on cascade boundary layer under different inlet conditions. New method is used to measure the total pressure in blade surface boundary layer directly using total pressure probe. Total pressure in both suction and pressure surfaces are acquired at different inlet conditions by changing incidence angle and inlet Mach number. In addition, a series of parameters related to boundary layer characteristics are calculated. The objective of the experiment is to investigate the influence of inlet flow conditions on them. The results indicate that influence of incidence angle is significant when other conditions are the same. Displacement thickness, momentum thickness as well as other parameters display some disciplines for variation. In contrast, inlet Mach number has only a small influence in that boundary layer becomes a litter thinner with increasing Mach number. Comparisons of experimental results with theoretical expectations demonstrate that the method in this experiment is effective and reliable.
Roles of the DYRK Kinase Pom2 in Cytokinesis, Mitochondrial Morphology, and Sporulation in Fission Yeast
Pengcheng Wu,Ran Zhao,Yanfang Ye,Jian-Qiu Wu
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0028000
Abstract: Pom2 is predicted to be a dual-specificity tyrosine-phosphorylation regulated kinase (DYRK) related to Pom1 in Schizosaccharomyces pombe. DYRKs share a kinase domain capable of catalyzing autophosphorylation on tyrosine and exogenous phosphorylation on serine/threonine residues. Here we show that Pom2 is functionally different from the well-characterized Pom1, although they share 55% identity in the kinase domain and the Pom2 kinase domain functionally complements that of Pom1. Pom2 localizes to mitochondria throughout the cell cycle and to the contractile ring during late stages of cytokinesis. Overexpression but not deletion of pom2 results in severe defects in cytokinesis, indicating that Pom2 might share an overlapping function with other proteins in regulating cytokinesis. Gain and loss of function analyses reveal that Pom2 is required for maintaining mitochondrial morphology independently of microtubules. Intriguingly, most meiotic pom2Δ cells form aberrant asci with meiotic and/or forespore membrane formation defects. Taken together, Pom2 is a novel DYRK kinase involved in regulating cytokinesis, mitochondrial morphology, meiosis, and sporulation in fission yeast.
Identification of a senescence-related protease in coriander leaves
Weibo Jiang,Xiangjuan Zhou,Yumei Zhao,Pengcheng Liu
Chinese Science Bulletin , 2002, DOI: 10.1360/02tb9246
Abstract: Senescence-related protease may play an important role in leaf senescence. By improved SDS-Gelatin-PAGE assay, a 63 ku senescence-related protease (63 SRP) in coriander leaves was identified. Activity of 63 SRP was increased in parallel to the advance of coriander leaf senescence, and inhibited by treating the leaf with gibberellic acid, and enhanced by ethylene treatment. The 63 SRP was suggested to be a serine protease based on the fact that its activity was inhibited by the protease inhibitor PMSF. The optimal temperature for the activity of the 70 ku protease was 50°C. The maximal activity was observed at pH 6–9, some activity could be observed on the gel slices incubated at pH 5 or 11. The 63 SRP was partly purified by the way of ammonium sulfate precipitation and then gel slicing after gel electrophoresis.
Effects of Microwave Frequency on Electron Energy Distribution Function and Air Breakdown Using the Fluid Model
Pengcheng Zhao;Cheng Liao;Wenbin Lin;Ju Feng
PIER M , 2012, DOI: 10.2528/PIERM12101201
Abstract: The non-equilibrium electron energy distribution function (EEDF) obtained via solving the Boltzmann equation is introduced into the fluid model, and the effects of the microwave frequency on the EEDF and air breakdown are investigated. Numerical simulations show that the breakdown threshold of the fluid model with the non-equilibrium EEDF agrees well with that of the reported experiments. The microwave frequency plays an important role on the shape of the non-equilibrium EEDF at low pressures. The breakdown time at the low pressures predicted by the Maxwellian EEDF is shorter than that from the non-equilibrium EEDF in low-frequency oscillating fields, while matches the latter in high-frequency oscillating fields.
Expression of Peptidylarginine Deiminase Type 4 in Ovarian Tumors
Lin Wang, Xiaotian Chang, Guangying Yuan, Yan Zhao, Pengcheng Wang
International Journal of Biological Sciences , 2010,
Abstract: Peptidylarginine deiminase type 4 (PADI4) converts arginine residues into citrulline. The current study focused on the expression of PADI4 in various subtypes of ovary cancers, and this study investigated the effects of estrogen on PADI4 expression in SKOV-3 cells that originated from ovary tumors. We utilized immunohistochemistry, real-time PCR and western blotting to analyze the expression of PADI4 in the tumor tissues and in the cell line that were cultured with estrodial-17β. PADI4 was detected in serious cystadenocarcinoma (n=39, positivity=100%), clear cell cancer (n=7, positivity= 100%), mucinous cystadenocarcinoma (n=6, positivity=100%), dysgerminoma (n=6, positivity=100%), squamous cell tumor (n=6, positivity=100%), sibnet-ring cell carcinoma (n=6, positivity=100%), endodermal sinus tumor (n=6, positivity=100%), germ cell tumors (n=6, positivity=100%) and immature teratoma (n=6, positivity=100%). However, PADI4 was either not detected or detected at low levels in granulosa cell tumor (n=6), malignant thecoma (n=6), ovarian cystadenoma (n=5) and normal ovarian tissue (n=11). For serious cystadenocarcinoma, all of the samples with high PADI4 expression belonged to the T1 and T2 stages of pTMN, whereas all of the samples that exhibited weak or moderate PADI4 expression belonged to the T3 and T4 stages. PADI4 was evenly distributed in the cytoplasm of tumor cells of serious cystadenocarcinoma that were classified as being grade II and III by histopathological scoring. However, PADI4 showed granular cellular distribution in the tumor tissues that were isolated from grade I cystadenocarcinoma. In addition, the PADI4 level was positively related with the ages of the patients that presented with serious adenocarcinoma (p=0.029). Real-time PCR and western blot analyses confirmed that PADI4 was expressed at higher levels in ovarian adenocarcinoma (n=8) compared to ovarian cystadenoma (n=5) (p< 0.05). The study also detected an increased level of PADI4 in SKOV-3 cells that were incubated with estrodial-17β in the range of 10-12 to 10-4M. The results suggest an important role for PADI4 in the tumorigenesis of ovary cancers that are under the regulation of estrogen.
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.
Nonlinear Analysis of the BOLD Signal
Zhenghui Hu,Xiaohu Zhao,Huafeng Liu,Pengcheng Shi
EURASIP Journal on Advances in Signal Processing , 2009, DOI: 10.1155/2009/215409
Abstract: The linearized filtering approach to the hemodynamic system is limited in capturing the inherent nonlinearities of physiological systems. The nonlinear estimation method therefore should be thought of as a natural way to access the nonlinear data assimilation problem. In this paper, we present a nonlinear filtering algorithm which is computationally expensive compared to the existing linearization filtering algorithms, for hemodynamic data assimilation, to address the deficiencies inherent to linearization. Simultaneous estimation of the physiological states and the system parameters have been demonstrated in a simulated and real data. The method provides more reasonable inference about the parameters of models for hemodynamic data assimilation.
Page 1 /37138
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.