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51.
Shanju Zhang Lingbo Zhu Marilyn L. Minus Han Gi Chae Sudhakar Jagannathan Ching-Ping Wong Janusz Kowalik Luke B. Roberson Satish Kumar 《Journal of Materials Science》2008,43(13):4356-4362
We report continuous carbon nanotube (CNT) fibers and yarns dry-drawn directly from water-assisted chemical vapor deposition
(CVD) grown forests with about 1-mm height. As-drawn CNT fibers exist as aerogel and can be transformed into more compact
fibers through twisting or densification with a volatile organic liquid. CNT fibers are characterized by scanning electron
microscopy, X-ray photoelectron spectroscopy, Raman microscopy, and wide-angle X-ray diffraction. Mechanical properties and
electrical conductivity of the post-treated CNT fibers are investigated. The resulting fibers show the work of rupture of
30 J/g and DC electrical conductivity of 5.0 × 104 S/m. 相似文献
52.
53.
Na Young Lee Seung Gi Lee Kyung Ha Ryu Il Soon Hwang 《Nuclear Engineering and Design》2007,237(7):761-767
Aged nuclear piping has been reported to undergo corrosion-induced accelerated failures, often without giving signatures to current inspection campaigns. Therefore, we need diverse sensors which can cover a wide area in an on-line application. We suggest an integrated approach to monitor the flow accelerated corrosion (FAC) susceptible piping. Since FAC is a combined phenomenon, we need to monitor as many parameters as possible and that cover wide area, since we do not know where the FAC occurs. For this purpose, we introduce the wearing rate model which focuses on the electrochemical parameters. Using this model, we can predict the wearing rate and then compare testing results. Through analysis we identified feasibility and then developed electrochemical sensors for high temperature application; we also introduced a mechanical monitoring system which is still under development. To support the validation of the monitored results, we adopted high temperature ultrasonic transducer (UT), which shows good resolution in the testing environment. As such, all the monitored results can be compared in terms of thickness. Our validation tests demonstrated the feasibility of sensors. To support direct thickness measurement for a wide-area, the direct current potential drop (DCPD) method will be researched to integrate into the developed framework. 相似文献
54.
55.
Cheol Park Won Sup Lee Se-Il Go Arulkumar Nagappan Min Ho Han Su Hyun Hong Gon Sup Kim Gi Young Kim Taeg Kyu Kwon Chung Ho Ryu Sung Chul Shin Yung Hyun Choi 《International journal of molecular sciences》2015,16(1):645-659
Evidence suggests that phytochemicals can safely modulate cancer cell biology and induce apoptosis. Here, we investigated the anti-cancer activity of morin, a flavone originally isolated from members of the Moraceae family in human leukemic cells, focusing on apoptosis. An anti-cancer effect of morin was screened with several human leukemic cell lines. U937 cells were most sensitive to morin, where it induced caspase-dependent apoptosis in a dose-dependent manner. It also induced loss of MMP (ΔΨm) along with cytochrome c release, down-regulated Bcl-2 protein, and up-regulated BAX proteins. The apoptotic activity of morin was significantly attenuated by Bcl-2 augmentation. In conclusion, morin induced caspase-dependent apoptosis through an intrinsic pathway by upregulating BAD proteins. In addition, Bcl-2 protein expression is also important in morin-induced apoptosis of U937 cells. This study provides evidence that morin might have anticancer properties in human leukemic cells. 相似文献
56.
介绍了通过改变磨机球荷尺寸组成,提高安徽铜陵冬瓜山铜矿选矿厂磨矿质量和磨机利用系数,降低磨矿球耗的方法。根据冬瓜山铜矿的矿石力学性质和磨矿条件,利用球径半理论公式精确计算合理的补装球荷尺寸组成,即m(Ф60)∶m(Ф40)=45∶55。工业试验结果表明,采用新的补装球荷后,磨矿细度(-0.074 mm)和中间可选粒级(-0.15+0.01 mm)含量分别提高了7.60和5.76个百分点,不合格粗粒级(+0.15 mm)含量和过细粒级(-0.01 mm)含量分别减少了2.90和2.86个百分点。磨机利用效率提高了9.8%,球耗降低了10.52%。球径半理论公式因计算方便、效果显著,具有很好的应用及推广价值。 相似文献
57.
Seung Ho Han Kyoung Sun Kim Ho Gi Kim Hyeung-Gyu Lee Hyung-Won Kang Jeong Seog Kim Chae Il Cheon 《Ceramics International》2010
The influence of processing parameters on phase formation and particle size of hydrothermally synthesized BiFeO3 powders was investigated. BiFeO3 powder was synthesized by dissolving bismuth nitrate and iron nitrate in KOH solution at temperatures ranging from 150 to 225 °C. X-ray diffraction patterns and scanning electron microscopy observation indicated that rod-like α-Bi2O3 phase was formed at initial stage of reaction and dissolved into ions to form thermodynamically stable BiFeO3 phase. Single-phase perovskite BiFeO3 has been formed using a KOH concentration of 8 M at a temperature of ≥175 °C in a 6 h reaction period. BiFeO3 particle growth was promoted by lowering the KOH concentration, or increasing the duration time or reaction temperature. The effects of processing conditions on the formation of crystalline BiFeO3 powders were discussed in terms of a dissolution–precipitation mechanism. The magnetization of the BiFeO3 powders at room temperature showed a weak a ferromagnetic nature. 相似文献
58.
Conventional dry‐jet wet fiber spinning techniques were used to fabricate continuous PAN/MWNT composite fibers with up to 20 wt.‐% nanotube loading. PAN at the MWNT interface exhibited lower solubility under thermodynamically favorable conditions than in bulk PAN, indicating good interfacial interaction. Due to the PAN/MWNT interaction at the interface, thermal shrinkage decreases with increasing MWNT loading (5 to 20 wt.‐%). For high MWNT loadings, PAN/MWNT composite fiber at 15 wt.‐% MWNT loading showed an axial electrical conductivity of 1.24 S · m?1. For all loadings, PAN/MWNT composite fibers exhibited higher tensile moduli than theoretically predicted by rule‐of‐mixture calculations, suggesting good reinforcement of the PAN by MWNT.
59.
Kyeong Joong Kim Chae Wook Lim Moon Gi Kang Kyu Tae Park 《IEEE transactions on image processing》1999,8(8):1142-1147
When approximating the shape of a region, a fixed bound on the tolerable distortion is set for approximating its contour points. An adaptive approximation bound for lossy coding of the contour points is proposed. A function representing the relative significance of the contour points is defined to adjust the distortion bound along the region contour allowing an adaptive approximation of the region shape. The effectiveness of the adaptive contour coding approach for a region-based coding system is verified through experiments. 相似文献
60.
Gi‐Wook Choi Se‐Kwon Moon Hyun‐Woo Kang Jiho Min Bong‐Woo Chung 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2009,84(4):547-553
BACKGROUND: The aim of this study was to examine the repeated batch production of bioethanol from sludge‐containing cassava mash as starchy substrate by flocculating yeast to improve volumetric bioethanol productivity and to simplify the process of a pre‐culture system. RESULTS: For the repeated batch production of bioethanol using cassava mash, the optimal recycling volume ratio was found to be 5%. The repeated batch fermentation was completed within 36 h, while the batch fermentation was completed after 42 h. Volumetric productivity, final ethanol concentration, and ethanol yield were attained to 2.15 g L?1 h?1, 83.64 g L?1, and 85.15%, respectively. Although cell accumulation in the repeated batch process is difficult due to the cassava mash, the repeated batch process using Saccharomyces cerevisiae CHFY0321 could exhibited 10‐fold higher initial viable cell number (1.7 × 107 CFU mL?1) than that of the batch process. CONCLUSION: The liquefied cassava powder was directly used for the repeated batch process without removal of sludge. Repeated batch bioethanol production by simultaneous saccharification and fermentation using self‐flocculating yeast could reduce process costs and accelerate commercial applications. This result was probably due in part to the effect of the initial viable cell density. Copyright © 2008 Society of Chemical Industry 相似文献