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Search Results: 1 - 10 of 23257 matches for " Zelong He "
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Properties of Phase Transformation of Ferroelectric Thin Films with Surface Layers  [PDF]
Lian Cui, Xu Xu, JiXin Che, Zelong He, Huijie Xue, Tianquan Lv
Journal of Modern Physics (JMP) , 2011, DOI: 10.4236/jmp.2011.29125
Abstract: Using the generalized Ginzburg-Landau-Devonshire theory, the characteristics of phase transformation of a ferroelectric thin film with surface layers are investigated. We study the effect of the surface layer on the properties (coercive field, critical thickness) of a ferroelectric thin film. Our theoretical results show that the surface layer is likely to answer for the emergence of phase transformation.
Thermodynamic Modeling for Open Combined Regenerative Brayton and Inverse Brayton Cycles with Regeneration before the Inverse Cycle
Lingen Chen,Zelong Zhang,Fengrui Sun
Entropy , 2012, DOI: 10.3390/e14010058
Abstract: A thermodynamic model of an open combined regenerative Brayton and inverse Brayton cycles with regeneration before the inverse cycle is established in this paper by using thermodynamic optimization theory. The flow processes of the working fluid with the pressure drops and the size constraint of the real power plant are modeled. There are?13?flow resistances encountered by the working fluid stream for the cycle model. Four of these, the friction through the blades and vanes of the compressors and the turbines, are related to the isentropic efficiencies. The remaining nine flow resistances are always present because of the changes in flow cross-section at the compressor inlet of the top cycle, regenerator inlet and outlet, combustion chamber inlet and outlet, turbine outlet of the top cycle, turbine outlet of the bottom cycle, heat exchanger inlet, and compressor inlet of the bottom cycle. These resistances associated with the flow through various cross-sectional areas are derived as functions of the compressor inlet relative pressure drop of the top cycle, and control the air flow rate, the net power output and the thermal efficiency. The analytical formulae about the power output, efficiency and other coefficients are derived with 13 pressure drop losses. It is found that the combined cycle with regenerator can reach higher thermal efficiency but smaller power output than those of the base combined cycle at small compressor inlet relative pressure drop of the top cycle.
Exergy analysis for combined regenerative Brayton and inverse Brayton cycles
Zelong Zhang, Lingen Chen, Fengrui Sun
International Journal of Energy and Environment , 2012,
Abstract: This paper presents the study of exergy analysis of combined regenerative Brayton and inverse Brayton cycles. The analytical formulae of exergy loss and exergy efficiency are derived. The largest exergy loss location is determined. By taking the maximum exergy efficiency as the objective, the choice of bottom cycle pressure ratio is optimized by detailed numerical examples, and the corresponding optimal exergy efficiency is obtained. The influences of various parameters on the exergy efficiency and other performances are analyzed by numerical calculations.
The Design of SQL Injection Analysis System based on Honeynet
Zelong Yin,Zhen Niu,Feifan Tong
Lecture Notes in Engineering and Computer Science , 2013,
Abstract:
The Effect Analysis of Different Experimental Methods for the Diagnosis of Invasive Pulmonary Aspergillosis in a Rat Model  [PDF]
Jiancong Lin, Wenming Xu, Ming Li, Yanli Xin, Yuanyuan Niu, Changran Zhang, Zelong Guo
International Journal of Clinical Medicine (IJCM) , 2013, DOI: 10.4236/ijcm.2013.410083
Abstract: Background: Consensus on the most reliable assays to detect invasive aspergillosis from minimally or noninvasive samples has not been reached. In this study, we compared the efficacy of an enzyme-linked immunosorbent assay (ELISA) for galactomannan (GM) detection and quantitative real-time PCR assay (qRT-PCR) for the diagnosis of invasive pulmonary aspergillosis in a rat model. Methods: Neutropenic, male Sprague-Dawley rats (specific pathogen free; 8 weeks old; weight, 200 ± 20 g) were immunosuppressed with cyclophosphamide and infected with Aspergillus fumigatus intratracheally. Tissue and whole blood samples were harvested on days 1, 3, 5, and 7 post-infection and examined with GM ELISA and qRT-PCR. Results: On day 7, A. fumigatus DNA was amplified from 14 of 48 whole blood samples from immunosuppressed infected rats: day 1 (0/12), day 3 (0/12), day 5 (6/12), day 7 (8/12) post infection. The sensitivity and specificity of the qRT-PCR assay were 29.2% and 100%, respectively. Receiver operating characteristic curve (ROC) analysis indicated a Ct cut-off value of 15.35, and the area under the curve (AUC) was 0.627. The GM assay detected antigen in sera obtained on day 1 (5/12), day 3 (9/12), day 5 (12/12), and day 7 (12/12) post-infection, and thus had a sensitivity of 79.2% and a specificity of 100%. The ROC of the GM assay indicated that the optimal cut-off value was 1.40 (specificity, 100%; AUC, 0.919). Conclusions: The GM assay was more sensitive than qRT-PCR assay in diagnosing invasive pulmonary aspergillosis in rats.
Protein trans-splicing based dual-vector delivery of the coagulation factor VIII gene
FuXiang Zhu,ZeLong Liu,XiaoYan Chi,HuiGe Qu
Science China Life Sciences , 2010, DOI: 10.1007/s11427-010-4011-7
Abstract: A dual-vector system was explored for the delivery of the coagulation factor VIII gene, using intein-mediated protein trans-splicing as a means to produce intact functional factor VIII post-translationally. A pair of eukaryotic expression vectors, expressing Ssp DnaB intein-fused heavy and light chain genes of B-domain deleted factor VIII (BDD-FVIII), was constructed. With transient co-transfection of the two vectors into 293 and COS-7 cells, the culture supernatants contained (137±23) and (109±22) ng mL 1 spliced BDD-FVIII antigen with an activity of (1.05±0.16) and (0.79±0.23) IU mL 1 for 293 and COS-7 cells, respectively. The spliced BDD-FVIII was also detected in supernatants from a mixture of cells transfected with inteinfused heavy and light chain genes. The spliced BDD-FVIII protein bands from cell lysates were visualized by Western blotting. The data demonstrated that intein could be used to transfer the split factor VIII gene and provided valuable information on factor VIII gene delivery by dual-adeno-associated virus in hemophilia A gene therapy.
Enhanced plasma factor VIII activity in mice via cysteine mutation using dual vectors
FuXiang Zhu,ZeLong Liu,Jing Miao,HuiGe Qu,XiaoYan Chi
Science China Life Sciences , 2012, DOI: 10.1007/s11427-012-4333-8
Abstract: Hemophilia A is caused by a genetic mutation in coagulation factor VIII (FVIII) gene and gene therapy is considered to be a promising strategy for its treatment. We recently demonstrated that co-delivery of two vectors expressing M662C mutated heavy and D1828C mutated light chain genes of B-domain-deleted coagulation factor VIII (BDD-FVIII) leads to inter-chain disulfide cross-linking and improved heavy chain secretion in vitro. In this study, co-injection of both M662C and D1828C mutated BDD-FVIII gene expression vectors into mice resulted in increased heavy chain secretion and coagulation activity in plasma in vivo. Approximately (239±56) ng mL 1 above endogenous levels of transgenic FVIII heavy chain was found in mouse plasma using a chain-specific ELISA. For FVIII coagulation activity, approximately (1.09±0.25) IU mL 1 above endogenous levels were detected in co-injected transgenic mouse plasma using a chromogenic assay. These data demonstrate that inter-chain disulfide bonds likely increase heavy chain secretion and coagulation activity in the plasma of transgenic mice with an improved efficacy of a dual-vector delivery of BDD-FVIII gene. These findings support our ongoing efforts to develop a gene therapy for hemophilia A treatment using dual-AAV vectors.
Effects of Reverse Radiation Noise on Millimeter-Wave Radiometric Imaging at Short Range
Taiyang Hu;Zelong Xiao;Jianzhong Xu;Li Wu
PIER M , 2011, DOI: 10.2528/PIERM11092606
Abstract: The existence of reverse radiation noise in the millimeter-wave (MMW) radiometric imaging system with a superheterodyne receiver seriously affects the imaging experiments carried out at short range, thus leading to the degradation of MMW radiometric images and difficulty in recognizing targets. Based on the generation mechanism of reverse radiation noise, the specific influence on imaging for relative radiometry is investigated in this paper, and some methods of eliminating or reducing this noise are proposed. Then, two series of comparative imaging experiments are conducted with a 3 mm band radiometric imaging system. Both theoretical analysis and experimental results are presented to validate the actual existence of interference-like stripes imposed by the reverse radiation noise. Moreover, it is proved that adopting an isolator in the MMW receiving front-end can effectively reduce the reverse radiation noise and significantly improve the imaging performance.
Support Loss and Q Factor Enhancement for a Rocking Mass Microgyroscope
Xiong Wang,Dingbang Xiao,Zelong Zhou,Xuezhong Wu,Zhihua Chen,Shengyi Li
Sensors , 2011, DOI: 10.3390/s111009807
Abstract: A rocking mass gyroscope (RMG) is a kind of vibrating mass gyroscope with high sensitivity, whose driving mode and sensing mode are completely uniform. MEMS RMG devices are a research hotspot now because they have the potential to be used in space applications. Support loss is the dominant energy loss mechanism influencing their high sensitivity. An accurate analytical model of support loss for RMGs is presented to enhance their Q factors. The anchor type and support loss mechanism of an RMG are analyzed. Firstly, the support loads, powers flowing into support structure, and vibration energy of an RMG are all developed. Then the analytical model of support loss for the RMG is developed, and its sensitivities to the main structural parameters are also analyzed. High-Q design guidelines for rocking mass microgyroscopes are deduced. Finally, the analytical model is validated by the experimental data and the data from the existing literature. The thicknesses of the prototypes are reduced from 240 μm to 60 μm, while Q factors increase from less than 150 to more than 800. The derived model is general and applicable to various beam resonators, providing significant insight to the design of high-Q MEMS devices.
The effect of a secretion-enhanced heavy chain on improving intein-based dual-vector co-delivery of a full-length factor VIII gene
FuXiang Zhu,ShuDe Yang,ZeLong Liu,Jing Miao,HuiGe Qu,XiaoYan Chi
Chinese Science Bulletin , 2011, DOI: 10.1007/s11434-010-4244-7
Abstract: Treatment of hemophilia A by gene therapy is adversely affected by inefficient FVIII secretion and the large FVIII gene, which is difficult to package in the promising adeno-associated virus (AAV) vectors. Inhibited secretion of FVIII is caused mainly by inefficient secretion of its heavy chain. Previously, we have employed a protein splicing-based dual-vector to co-transfer a B-domain-deleted FVIII (BDD-FVIII) gene, suggesting that the light chain, covalently ligated to a co-expressed heavy chain can improve the secretion of spliced BDD-FVIII. However, its level of secretion was affected by inefficient secretion the heavy chain. Here, we studied the effect of a mutant heavy chain with L303E/F309S substitutions, which enhance FVIII secretion on the heavy chain itself and spliced FVIII when using a protein splicing-based split-delivery of a full-length FVIII gene. Eukaryotic vectors expressing Ssp DnaB intein-fused mutant heavy and light chains were transiently co-transfected into cultured COS-7 cells. A spliced FVIII protein was seen in co-transfected cells by Western blot analysis. The heavy chain was secreted by cells transfected with the mutant heavy chain gene alone at (39±11) ng/mL and this secretion increased to (123±13) ng/mL when cells were co-transfected with the light chain gene, which was greater than the secretion of wild-type heavy chain. The amount of spliced FVIII in the culture supernatant of co-transfected cells was (86±14) ng/mL, with an activity of (0.61±0.08) IU/mL, which was greater than that of wild-type FVIII co-transfected cells. Spliced FVIII and bioactivity were also detected in the combined culture supernatant of cells individually transfected with mutant heavy and light chain gene at a higher level than that of combined wild-type heavy and light chain transfections. This suggested that the heavy chain with improved secretion markedly increased the efficacy of protein splicing-based split delivery of the full-length FVIII gene using a dual-vector. These results encourage the transfer of this technology to an animal model using a dual-AAV vector.
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