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91.
Jaeyoung Jang Sooji Nam Kyuhyun Im Jaehyun Hur Seung Nam Cha Jineun Kim Hyung Bin Son Hwansoo Suh Marsha A. Loth John E. Anthony Jong‐Jin Park Chan Eon Park Jong Min Kim Kinam Kim 《Advanced functional materials》2012,22(5):1005-1014
The preparation of uniform large‐area highly crystalline organic semiconductor thin films that show outstanding carrier mobilities remains a challenge in the field of organic electronics, including organic field‐effect transistors. Quantitative control over the drying speed during dip‐coating permits optimization of the organic semiconductor film formation, although the kinetics of crystallization at the air–solution–substrate contact line are still not well understood. Here, we report the facile one‐step growth of self‐aligning, highly crystalline soluble acene crystal arrays that exhibit excellent field‐effect mobilities (up to 1.5 cm V?1 s?1) via an optimized dip‐coating process. We discover that optimized acene crystals grew at a particular substrate lifting‐rate in the presence of low boiling point solvents, such as dichloromethane (b.p. of 40.0 °C) or chloroform (b.p. of 60.4 °C). Variable‐temperature dip‐coating experiments using various solvents and lift rates are performed to elucidate the crystallization behavior. This bottom‐up study of soluble acene crystal growth during dip‐coating provides conditions under which one may obtain uniform organic semiconductor crystal arrays with high crystallinity and mobilities over large substrate areas, regardless of the substrate geometry (wafer substrates or cylinder‐shaped substrates). 相似文献
92.
Misun Sung Sung Sun Park Sung-Soo Kim Chan-Kyu Han Jung-Mu Hur 《Food science and biotechnology》2014,23(5):1615-1621
The antioxidant activities and hepatoprotective effects of Schizandra chinensis Baill. extracts (SCE) were evaluated. The contents of the active components schisandrin, schisandrin C, gomisin A, and gomisin N in SCE were 8.802±1.390, 1.011±0.203, 0.954±0.191, and 3.351±0.829 mg/g, respectively. The antioxidant activity of SCE was measured based on the DPPH free radical scavenging activity and the superoxide dismutase (SOD)-like activity. The IC50 values for the DPPH radical scavenging activity and SOD-like activity were 18.1 and 44.2mg/mL, respectively. The protective effect of SCE against alcohol-induced oxidative injury in HepG2 cells was investigated. Cells pretreated with SCE (100–400 μg/mL) showed an increased resistance to oxidative stress in a dose-dependent manner. Expressions of Bcl-2 and pro-caspase-3 proteins were induced by SCE in HepG2 cells. SCE can be useful for management of antioxidant and hepatoprotective effects. 相似文献
93.
Steam reforming (SR) of glycerol for the production of hydrogen was investigated over the nano-sized Ni-based catalysts. The Ni-based catalysts were prepared by solid phase crystallization and impregnation methods, and characterized by N2 physisorption, CO chemisorption, XRD, SEM, and TEM techniques. The Ni/gamma-Al2O3 catalyst showed higher conversion and H2 selectivity. However, it was slowly deactivated due to the carbon formation on the surface of catalyst and the sintering. It was found that the Ni based hydrotalcite-like catalyst (spc-Ni/MgAl) showed higher catalytic activity to prevent carbon formation than Ni/gamma-Al2O3 catalyst in the SR of glycerol. 相似文献
94.
Ahn JK Park KW Hur SG Kim CS Lee JY Yoon SG 《Journal of nanoscience and nanotechnology》2011,11(1):189-194
The feasibility of new InSbTe (IST) chalcogenide materials at the deposition temperatures of 225 and 250 degrees C using metalorganic chemical vapor deposition (MOCVD) for phase-change random access memory (PRAM) applications was investigated. Samples grown at 225 degrees C consisted of the main InTe phase, including a small amount of Sb. On the other hand, samples grown at 250 degrees C included the crystalline phases of InSb and InSbTe. MOCVD-IST materials are powerful candidates for highly-integrated PRAM applications. 相似文献
95.
Cheng-Kui Jiang Kyung-Ah Lee Cheon-Jei Kim Joo-Yeon Lee Sun-Jin Hur Si-Kyung Lee 《Food science and biotechnology》2013,22(6):1717-1724
The quality characteristics of cheonggukjang containing Phellinus linteus extracts (PLE) and its cytotoxicity in Hep-2 and SK-MS-cells were investigated. Cheonggukjang containing 0.3% PLE showed the highest protease activity (7th aging day). The reducing sugar content and the amylase activity of cheonggukjang supplemented with 0.3% PLE increased immediately on the 1st aging day, and decreased slightly until the 15th aging day. All samples showed an increase in the amino-type nitrogen content. The dominant volatile compound detected using chromatography-mass spectrophotometry was 2,5-dimethyl pyrazine with the highest peak area value of 17.36% observed in cheonggukjang containing 0.3% PLE (3rd aging day). Cheonggukjang containing 0.3% PLE exhibited the best taste and acceptability with the least unpleasant odor. Cheonggukjang supplemented with PLE had a higher antitumor activity against SK-MES-1 and Hep-2 cells than a control. Hep-2 cells treated with a 10 mg/mL extract of cheonggukjang containing 0.3% PLE showed the highest growth inhibition rate of 84.74%. 相似文献
96.
Süleyman Köytepe M. Hurşit Demirel Turgay Seçkin 《Journal of Inorganic and Organometallic Polymers and Materials》2013,23(5):1104-1112
A novel metallo-supramolecular polytopic ligand was synthesized from the attachment reaction involving an amino group-functionalized multi-wall carbon nanotube and 4-chloro-2,2′:6′,2″-terpyridine used for the preparation of metallo-supramolecular polymers with Co(II) or Ni(II) ions. Different colors were observed depending on either the ligands or the metal ions in this type of supramolecular assembly. The created supramolecular polymers were characterized by means of structure, morphology, and stimuli-responsive performance employing scanning electron microscopy, amperometric techniques, UV–Vis and Fourier transform infrared spectroscopy. UV–Vis spectroscopy and cyclic voltammetry studies confirmed that both the optical and electrochemical properties of metallo-supramolecular materials are affected by the substituent at the pyridine periphery. 相似文献
97.
A Distributed Medium Access Control (D-MAC) protocol based on UWB for high-rate Wireless Personal Area Networks is specified by the WiMedia Alliance. D-MAC protocol is suitable for ubiquitous connection in home networks, military/medical applications due to its inexpensive cost, low power consumption, high data rate, and distributed approach. In contrast to IEEE 802.15.3, D-MAC makes all devices have the same functionality. And its networks are self-organized and provide devices with functions such as access to the medium, channel allocation to devices, data transmission, quality of service and synchronization in a distributed manner. D-MAC fundamentally removes the problems of the centralized MAC approach revealed at IEEE 802.15.3 MAC by adopting a distributed architecture. However, the current D-MAC can’t prevent QoS degradations, occurred by mobile nodes with low data rate due to bad channel status, which cause critical problems in QoS provisioning to isochronous streams and mobile applications. Therefore, we propose a distributed cooperative MAC protocol for multi-hop WiMedia networks using virtual MIMO links. Based on instantaneous Channel State Information among WiMedia devices, our proposed protocol can intelligently select the transmission path with higher data rate to provide advanced QoS with minimum delay for real-time multimedia streaming services. 相似文献
98.
Yong-Jun Lee Tae-Yang Shim Kwang-O Lee Man-Dae Hur Sung-Su Kang 《Journal of Mechanical Science and Technology》2013,27(8):2323-2329
A dual mass flywheel has positive effects on noise and vibration problems, but there are still difficulties securing sufficient component durability during the development process to increase the output. In this study, the fatigue life of a drive plate, a component in the power transmission path that is often fractured by cyclic loading, is evaluated in relation to heat treatment, and the effect of heat treatment on the fatigue life is studied. For this purpose, a fatigue test and rig test are conducted on both the raw material and heat-treated material of the drive plate. Based on the fatigue material properties obtained from the fatigue tests and the boundary conditions of the rig test, a fatigue analysis is conducted to predict the fatigue life. The heat-treated material has a fatigue life five times longer than the raw material in both the rig test and fatigue analysis. The fatigue life evaluation method is validated through a comparison of the life predicted by the fatigue analysis and the test results of the rig test. 相似文献
99.
Sang Ho Kang Shin Goo Hur Hee Woo Lee Tae Hyun Nam 《Metals and Materials International》2000,6(4):381-387
Ti-Ni and Ti-Ni-Cu alloy powders have been fabricated by ball milling after which their microstructures and transformation
behaviors were investigated by means of scanning electron microscopy, X-ray diffraction, energy dispersive X-ray analysis,
transmission electron microscopy and differential scanning calorimetry. The powders of as-milled Ti-Ni-Cu alloys whose Cu-content
is less than 5 at.% were mixtures of crystal and amorphous, whereas those alloy powders whose Cu-content is more than 10 at.%
were crystalline. The B19’ martensite is formed in the Ti-Ni-Cu alloy powders whose Cu-content is less than 10 at.%, whereas
the B19 and B19’ martensites coexist in those whose Cu-content is more than 10 at.%. The martensitic transformation range
became wider with increasing rotating speed, and so endothermic and exothermic peaks obtained from differential scanning calorimetry
were indiscernible. 相似文献
100.
Performances of combined adsorption and chemical precipitation were evaluated as one of the options for pretreatment or post-treatment
of a municipal solid waste (MSW) landfill leachate and leachate from an industrial solid waste landfill. The COD and color
removals of the leachate from a MSW landfill were 35% and 33% at an alum dose of 300 mg/L with preceding PAC (powdered activated
carbon) dose of 200 mg/L, respectively. For MSW leachate, the combined adsorption and coagulation process showed 2.3 times
higher COD removal at PAC dose of 200 mg/L and alum dose of 500 mg/L than the unit process of adsorption with poor settleability.
The COD removal was accomplished mainly by adsorption, while coagulation was a key mechanism of color removal. The COD and
color of the biologically treated leachate from an industrial solid waste landfill were removed up to 32% and 68%, respectively,
at addition of 490 mgAlum/L and 1,000 mgPAC/L in adsorption-coagulation process with pH control. Combined adsorption and coagulation
process with pH control showed better COD and color removal than the process without pH control. The color removal was influenced
greatly by pH control, while COD removal was not. No difference in removal efficiency was observed between adsorption-coagulation
and coagulation-adsorption. Maximum net increases in the COD and color removals by the adsorption-coagulation process were
40% and 46%, respectively, compared with the removals by sole chemical precipitation. The Freundlich isotherm exclusively
described the adsorption of leachate components on the PAC. Thus, a combined adsorption and coagulation process was considered
to be effective for pre-treatment or post-treatment of landfill leachate, and has distinct features of simple, flexible, stable
and reliable operation against fluctuation of leachate quality and flowrate. 相似文献