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許成哲,金仁澤 명지대학교 산업기술연구소 2005 産業技術硏究所論文集 Vol.24 No.-
This paper presents a method for compression hyperspectral images. A compression system built on this concept can obtain high compression rate and low information loss. Band images are extracted first from the hyperspectral data. Next these band images are stacked by order of wavelength and form a stack image, and obtain column vectors from the stack image. We transform this column vectors to obtain principal-component vectors by using PCT according to given number of principal component, and the obtained principal-component vectors become compression data. Reconstruction proceed with inverse PCT.
Glycerol steam reforming over Ni/γ-Al2O3 catalysts modified by metal oxides
Cheng-Hua Xu,Zun-Yu Huang,Chuan-Qi Liu,Hui-Wen Xiao,Jun Chen,Yong-Xiang Zhang,Ya-Cong Lei 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.3
The metal oxides modified Ni/γ-Al2O3 catalysts for glycerol steam reforming were prepared by impregnation. Characterization results of fresh catalysts indicated that the molybdates modification abated the acidity and the stronger metal-support interaction of Ni/γ-Al2O3 catalysts, leading to a stable catalytic activity. Especially, NiMoLa-CaMg/γ-Al2O3 (NiMoLa/CMA) catalyst exhibited no deactivation along with glycerol complete conversion to stable gaseous products containing 69% H2, 20% CO and 10% CO2 during time-on-stream of 42 h. TPO of spent Ni/γ-Al2O3catalysts modified by different components showed that the carbon deposit on acidic sites and NiAl2O4 species led to catalysts deactivation. A lower reforming temperature and a higher LHSV and glycerol content were helpful to the production of syngas from GSR over NiMoLa/CMA; the reverse conditions would improve the formation of H2.
Xu, Chang-Cheng,Kuang, Tingyun,Li, Liangbi,Lee, Choon-Hwan 부산대학교 유전공학연구소 2000 분자생물학 연구보 Vol.16 No.-
The relationship between D1 protein turnover, carotene synthesis zeaxanthin epoxidation was examined in rice (Oryza sativa L.) leaves during recovery subsequent to chilling treatments at 500 (moderate light)or 1000 μmol photons m^-2s^-1 (high light) for 3 h. When recovery was monitored in te light, the decrease in the level of zeaxanthin was closely paralleled by the slow increase in the efficiency of photosystem (PS) Ⅱ. Both these processed were greatly slowed down in the presence of lincomycin, an inhibitor of chloroplast-coded protein synthesis. In leaves chilled in moderate light, the inhibitory effect of lincomycin on zeaxanthin decrease was largely eliminated by infiltration with dithiothereitol, an inhibitor of de-epoxidase, suggesting a stimulation of violaxanthin de-epoxidation rather than an inhibition of zeaxanthin epoxidation in the presence of lincomycin. In high-light-chilled leaves lincomycin had little impact on violaxanthin de-epoxidation but strikingly blocked the process of zeaxanthin epoxidation. Furthemore both PSⅡ revovery and zeaxidation in high-light-chilled leaves were almost completely suppressed by incubation with either fluridone or norflurazon, two inhibitors of carotene synthesis. The possible reason for parallel changes in the level of zeaxanthin and PSⅡ efficiency during recovery from photoinhibition is discussed.
A MIXED CORE FOR SUPERCRITICAL WATER-COOLED REACTORS
Cheng, Xu,Liu, Xiao-Jing,Yang, Yan-Hua Korean Nuclear Society 2008 Nuclear Engineering and Technology Vol.40 No.2
In this paper, a new reactor core design is proposed on the basis of a mixed core concept consisting of a thermal zone and a fast zone. The geometric structure of the fuel assembly of the thermal zone is similar to that of a conventional thermal supercritical water-cooled reactor(SCWR) core with two fuel pin rows between the moderator channels. In spite of the counter-current flow mode, the co-current flow mode is used to simplify the design of the reactor core and the fuel assembly. The water temperature at the exit of the thermal zone is much lower than the water temperature at the outlet of the pressure vessel. This lower temperature reduces the maximum cladding temperature of the thermal zone. Furthermore, due to the high velocity of the fast zone, a wider lattice can be used in the fuel assembly and the nonuniformity of the local heat transfer can be minimized. This mixed core, which combines the merits of some existing thermal SCWR cores and fast SCWR cores, is proposed for further detailed analysis.
Influence of FeSe doping on superconducting properties of MgB2 by hybrid microwave method
Cheng Cheng,Zhenjie Feng,Qing Li,Xu Wang,Chuan Yu,Hao Chu,Ya Yang,Changqin Liu,Yiming Cao,Zhe Li,Jingzhe Chen,Chao Jing,Shixun Cao,Jincang Zhang 한국물리학회 2017 Current Applied Physics Vol.17 No.11
The effect of FeSe doping on the physical properties of MgB2 is studied. Bulk samples of the FeSe doped MgB2 with weight ratio x ðFeSe : MgB2Þ ¼ 0%; 3%; 7% and 10% were prepared by hybrid microwave method. It is proved that FeSe is not stable together with MgB2. Fe2þ enters into MgB2 lattice, some Mg2þ and Se2『 are combined into the new impurity compound MgSe. The superconducting transition temperature (Tc) slightly decreased with increasing doping content of FeSe from R-T and M-T curves, which results from the substitution of Mg2þ by Fe2þ in the MgB2 lattice. The Jc increase slightly with the FeSe doping content increasing from 3 wt % to 10 wt %, which results from the increasing MgSe impurity pinning centers.
Study of the Flow in Centrifugal Compressor
Xu, Cheng,Amano, Ryoichi Samuel Korean Society for Fluid machinery 2010 International journal of fluid machinery and syste Vol.3 No.3
Reducing the losses of the tip clearance flow is one of the keys in an unshrouded centrifugal compressor design and development because tip clearances are large in relation to the span of the blades and also centrifugal compressors produce a sufficiently large pressure rise in single stage. This problem is more acute for a low flow high-pressure ratio impeller design. The large tip clearance would cause flow separations, and as a result it would drop both the efficiency and surge margin. Thus a design of a high efficiency and wide operation range low flow coefficient centrifugal compressor is a great challenge. This paper describes a recent development of high efficiency and wide surge margin low flow coefficient centrifugal compressor. A viscous turbomachinery optimal design method developed by the authors for axial flow machine was further extended and used in the centrifugal compressor design. The compressor has three main parts: impeller, a low solidity diffuser and volute. The tip clearance is under a special consideration in this design to allow impeller insensitiveness to the clearance. A patented three-dimensional low solidity diffuser design method is used and applied to this design. The compressor test results demonstrated to be successful to extend the low solidity diffusers to high-pressure ratio compressor. The compressor stage performance showed the total to static efficiency of the compressor being about 85% and stability range over 35%. The test results are in good agreement with the design.
Clinical Applications of CT Myocardial Perfusion Imaging
Cheng Xu,Yan Yi,Yining Wang 아시아심장혈관영상의학회 2020 Cardiovascular Imaging Asia Vol.4 No.4
With the continuous development of CT technology, myocardial CT perfusion imaging (CTP) has exhibited great advantages and been shown to have incremental value over coronary CT angiography, providing functional evaluation of coronary artery disease (CAD). Comprehensive assessment of CAD using cardiac CT has become feasible. This article introduces the preliminary clinical experience and advances with CTP and briefly reviews the feasibility verification, diagnostic performance, clinical strategy optimization and prognostic evaluation of CTP.
Xu, Lu-Wei,Qian, Ming,Jia, Rui-Peng,Xu, Zheng,Wu, Jian-Ping,Li, Wen-Cheng,Huang, Wen-Bin,Chen, Xing-Guo Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.4
The aim of this study was to investigate the expression and significance of microsomal prostaglandin synthase-1 (mPGES-1) and Beclin-1 in the development of prostate cancer (PCa). Immunohistochemistry was performed on paraffin-embedded sections with rabbit polyclonal against mPGES-1 and Beclin-1 in 40 PCa, 40 benign prostatic hyperplasia (BPH) and 10 normal prostate specimens for this purpose. Quantitative real-time polymerase chain reaction (qRT-PCR) was applied for mRNA expression of mPGES-1 and Beclin-1, while MTT assays were used to ascertain the best working concentration of the mPGES-1 inhibitor (CAY10526). The effect of CAY10526 treatment on expression of Beclin-1 in DU-145 cells was studied using Western blot analysis. Localization of Beclin-1 and mPGES-1 was in endochylema. Significant differences in expression was noted among PCa, BPH and normal issues (P<0.05). Beclin-1 expression inversely correlated with mPGES-1 expression in PCa tissue (P<0.05). CAY10526 could significantly block mPGES-1 expression and the proliferation of DU-145 cells (P<0.05), while increasing Beclin-1 levels (P<0.05). Overexpression of mPGES-1 could decrease the autophagic PCa cell death. Inhibiting the expression of mPGES-1 may lead to DU-145 cell death and up-regulation of Beclin-1. The results suggest that inhibition of mPGES-1 may have therapeutic potential for PCa in the future.
Xu, Cheng-Hua,Jin, Tai-Huan,Jhung, Sung-Hwa,Hwang, Jin-Soo,Chang, Jong-San,Qiu, Fa-Li,Park, Sang-Eon Korean Chemical Society 2004 Bulletin of the Korean Chemical Society Vol.25 No.5
Ti-ZSM-5 prepared by secondary synthesis, from the reaction of H-ZSM-5 with vapor phase $TiCl_4$, was characterized with several physicochemical techniques including FT-IR and UV/VIS-DRS. It was found that zeolite structure, surface area and pore volume did not change, and the framework aluminum could not be replaced by titanium atom during the secondary synthesis of Ti-ZSM-5. The incorporation of titanium into the framework might be due to reaction of $TiCl_4$with the silanol groups associated with defects or surface sites. The formation of extra-framework titanium could not be avoided, unless the samples were further treated by water vapor at 550 $^{\circ}C$ or higher temperature. High temperature steam treatment of Ti-ZSM-5 prepared by chemical vapor deposition with $TiCl_4$was efficient to prevent the formation of non-framework titanium species. Ti-ZSM-5 zeolites prepared in this work contained only framework titanium species and exhibited improved catalytic property close to TS-1 prepared by hydrothermal synthesis.