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111.
TAIMIN NOH JINSEONG KIM YONGTAE KIM HO HWAN CHUN MIN-SEOK JEON HEESOO LEE 《Bulletin of Materials Science》2013,36(7):1261-1266
Cu-free and Cu-doped LSM system, La0·8Sr0·2Mn1???x Cu x O3???δ (x?=?0, 0·2), with perovskite structure were prepared using an EDTA combined citrate process and the effects of Cu ion at B-site were investigated. Electrical conductivity and polarization resistance of the Cu-doped LSM were 210 S·cm???1 at 750 °C, and 2·54 Ω · cm2 at 800 °C, respectively which were better than those of the Cu-free LSM. This indicated that the electrode performance of LSM was improved by the addition of Cu. The oxidation state of Mn ions increased with addition of Cu. The increase in the oxidation state of Mn ions was due to the formation of Mn4?+? ions and oxygen vacancies. The addition of Cu ions to LSM systems could lead to enhanced electrode performance for oxygen reduction reactions originating from the change in valence of Mn ions. 相似文献
112.
YASANTHA ATHUKORALA KI-WAN LEE CHOONBOK SONG CHANG-BUM AHN TAI-SUN SHIN YONG-JUN CHA FEREIDOON SHAHIDI YOU-JIN JEON 《Journal of Food Lipids》2003,10(3):251-265
Grateloupia filicina is an important alga cultivated as a source of food in Korea and Japan. In order to examine its potential antioxidant activity, crude extracts of G. filicina were evaluated for their effect on scavenging of reactive oxygen species (DPPH, H, H2 O2 and O2 ) and inhibition of lipid peroxidation. The activities of these extracts were compared with those of commercial antioxidants such as BHA, BHT and α-tocopherol. The methanolic extract (2 mg/mL) of G. filicina scavenged 82% of DPPH radicals which is almost three times higher than that of BHT. The same methanolic extract scavenged 65% of superoxide onion which is almost two times higher than that of BHT and α-tocopherol. In contrast, the extracts in chloroform and carbon tetrachloride inhibited lipid peroxidation more effectively than all commercial antioxidants tested in a linoleic acid model system. 相似文献
113.
Seonghun Park Cong-Truyen Duong Jae-Hoon Lee Sang-Soo Lee Kwon Son 《International Journal of Precision Engineering and Manufacturing》2010,11(1):129-136
The objective of this study is to investigate the effect of different Atomic Force Microscope (AFM) tip geometries (sharp-conical
and spherical tips) on the microscale Young’s modulus of bovine articular cartilage and agarose gel that is calculated by
the method of the average point-wise modulus. The measurements of the microscale Young’s moduli of 3% agarose gel under a
conical AFM tip (20.9±4.9 kPa) and under a spherical AFM tip (17.5±3.0 kPa), averaged over an indentation depth of 600 nm,
were comparable. However, the microscale Young’s moduli of articular cartilage, as measured with a conical AFM tip (116.9±62.9
kPa), were significantly higher than the corresponding values under a spherical AFM tip (30.9±14.3 kPa). The results of the
current study suggest that the AFM tip geometry affects the microscale measurements of the mechanical properties on the surfaces
of biological materials. The findings of the study can help to elucidate more accurately the microscale mechanical properties
on the surface layers of diverse biological materials including tissue-engineered cartilages with different material characteristics. 相似文献
114.
TiO2 hollow spheres are employed as an additive of oligomer electrolytes for dye-sensitized solar cells (DSSCs). The measurement of steady-state currents confirms that introducing TiO2 hollow spheres can facilitate ionic diffusion in oligomer electrolytes. Even compared with conventional nanoparticle additives, the hollow spheres are more favorable to increase the diffusion coefficients of I? and I3? in oligomer electrolytes. Furthermore, the hollow structure with a submicron size is effective to scatter incident light and thereby enhance the light-harvesting efficiency of DSSCs. The energy-conversion efficiency of the DSSCs with TiO2 hollow sphere additives significantly improves up to 7.22% due to the facilitated ionic diffusion and the enhanced light-harvesting efficiency. 相似文献
115.
Lignite is a low rank coal which is evenly distributed throughout the world and accounts for 45% of the total coal reserves. As it has a higher moisture content, its moisture content must be reduced in order to utilize it in power plant. In the present work, experiments on lignite has been done using a lab scale fluidized-bed reactor. Drying lignite through fluidized-bed reactor has a higher drying rate because there is good contact between particles and gas in the fluidized-bed reactor. Fluidized-bed dryin... 相似文献
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We have experimentally demonstrated that the use of an optical receiver with decision threshold level adjustment (DTLA) improved the performance of an upstream transmission in reflective semiconductor optical amplifier (RSOA)-based loopback wavelength division multiplexing-passive optical network (WDM-PON). Even though the extinction ratio (ER) of the downstream signal was as much as 9 dB and the injection power into the RSOA at the optical network unit was about ?24 dBm, we successfully obtained error-free transmission results for the upstream signal through careful control of the decision threshold value in the optical receiver located at optical line terminal (OLT). Using an optical receiver with DTLA for upstream signal detection overcame significant obstacles related to the injection power into the RSOA and the ER of the downstream signal, which were previously considered limitations of the wavelength remodulation scheme. This technique is expected to provide flexibility for the optical link design in the practical deployment of a WDM-PON. 相似文献
120.
Sang-Soo Yeo Soo-Cheol Kim Sung Kwon Kim Gilcheol Park Seok Soo Kim Ki-Sung Yang Sung-Eon Cho 《Wireless Personal Communications》2009,51(1):165-178
Radio Frequency Identification (RFID) Technology is a contactless automatic identification technology using radio frequency.
For this RFID technology to be widely spread, the problem of privacy invasion should be solved. There are many research works
in progress to solve the RFID privacy problems. Most of works for solving this problem have focused on developing light-weight
cryptographic modules which can be embedded into RFID tags, but some of them used a proxy agent approach that control communications
between the tag and the reader for protecting user privacy. The later approach is very useful and practical in terms of manufacturing
low-cost tag hardware. However, all schemes of this approach have some problems in ownership transfer and forgery detection.
In this paper, we are focusing on the proxy agent approach and we suggest an advanced agent scheme that guarantees not only
privacy protection but also forgery detection. And our scheme is more scalable than other agent schemes so far. 相似文献