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51.
Jung Bin In Bin Xiang David J. Hwang Sang-Gil Ryu Eunpa Kim Jae-Hyuck Yoo Oscar Dubon Andrew M. Minor Costas P. Grigoropoulos 《Applied Physics A: Materials Science & Processing》2014,114(1):277-285
We observe laser-induced grain morphology change in silicon nanopillars under a transmission electron microscopy (TEM) environment. We couple the TEM with a near-field scanning optical microscopy pulsed laser processing system. This novel combination enables immediate scrutiny on the grain morphologies that the pulsed laser irradiation produces. We find unusual transformation of the tip of the amorphous or polycrystalline silicon pillar into a single crystalline domain via melt-mediated crystallization. On the basis of the three-dimensional finite difference simulation result and the dark field TEM data, we propose that the creation of the distinct single crystalline tip originates from the dominant grain growth initiated at the apex of the non-planar liquid–solid interface. Our microscopic observation provides a fundamental basis for laser-induced conversion of amorphous nanostructures into coarse-grained crystals. 相似文献
52.
Masayuki Kirihara Takuya Noguchi Nobuhiro Okajima Sayuri Naito Yuki Ishizuka Aiko Harano Hiroyuki Tsukiji Ryu Takizawa 《Tetrahedron》2012,68(5):1515-1520
The reaction of dithioacetals with 30% hydrogen peroxide in the presence of catalytic amounts of tantalum(V) and iodide ion effectively produced carbonyl compounds in high yields. Dithioacetals also can be deprotected using the niobium(V) catalyzed oxidation of iodide ion by hydrogen peroxide under mild conditions. 相似文献
53.
54.
Gi-Seong Ryu 《Molecular Crystals and Liquid Crystals》2017,652(1):207-212
Most of the merit of organic thin film transistors (OTFTs) is that they can be manufactured using cost effective processes. However, expensive gold (Au) electrodes have usually been used as a source/drain (S/D), due to their benign energy level matching, high air stability, and easy patternability. In this article, we report a simple method for improving the charge injection from a low cost molybdenum (Mo) electrode to organic semiconductors in OTFTs by incorporating a dodecanoic acid (DA)–based self-assembled monolayer (SAM). The OTFT performance is remarkably improved when compared to the devices with a pristine Au electrode. The hole carrier mobilities (hole μFET) were ~0.13 (rr-P3HT), ~0.55 (PC12TV12T) and ~0.72 (P2100) cm2/V·sec. 相似文献
55.
Zaesung No Shi Yong Ryu Seong-Kie Kim Jong Woong Ahn Bok Ju Song Keun Jae Kim 《合成通讯》2013,43(5):887-892
Thermal or base-promoted conversion of 5′-O-TBDMS-3′-O-(1H-imidazole-1-thiocarbonyl)thymidine (1) afforded 5′-O-TBDMS-2,3′-anhydro-thymidine (2), a pivotal intermediate for the transformation of the 3′-hydroxy group of 2′-deoxyribonucleosides, in high yield. 相似文献
56.
Hyungju Ahn Yonghoon Lee Hoyeon Lee Yoonkeun Kim Du Yeol Ryu Byeongdu Lee 《Journal of polymer science. Part A, Polymer chemistry》2013,51(7):567-573
We present an overview of the recent progress on the phase transition in the block copolymer (BCP) films in terms of the interfacial interactions effects of the substrates and the χ (Flory-Huggins segmental interaction parameter) effects between the two blocks. For the BCP films thinner than a critical thickness (Lc) above which the transition is independent of film thickness, the order-to-disorder transition (ODT) increased or decreased with decreasing film thickness depending on the interfacial interaction types. The rapid and slow changes in the ODT were attributed to the relative magnitude of enthalpic contribution to χ between two blocks. Interestingly, a periodic amplification in the block composition for the BCP films suppressed the compositional fluctuation in the film geometry, resulting in the ODT shifts from the bulk ODTs above Lc. This effect of the BCP films was more illustrated by the ODT shift effects depending on the strength of the preferential interactions on the substrates. © 2013 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2013 相似文献
57.
Dr. Ryu Yamasaki Dr. Masato Ohashi Kyotaro Maeda Takuya Kitamura Minami Nakagawa Korehito Kato Tetsushi Fujita Ryohei Kamura Kazuto Kinoshita Dr. Hyuma Masu Prof. Dr. Isao Azumaya Prof. Dr. Sensuke Ogoshi Prof. Dr. Shinichi Saito 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(10):3415-3425
A detailed study of the Ni‐catalyzed [4+3+2] cycloaddition reaction between ethyl cyclopropylideneacetate and dienynes has been conducted, resulting in the development of a new method for the synthesis of compounds containing nine‐membered rings. We studied the reactivity of various dienynes, together with their substituent and conformational effects. The mechanism of the reaction was probed by examining the stoichiometric reactions of the Ni complexes and dienynes. 相似文献
58.
Sieving properties of end group‐halogenated Pluronic polymer matrix in DNA separation under nondenaturing CE analysis 下载免费PDF全文
Hee Sung Hwang Gi Won Shin Aaron Cohen Chang Yeol Ryu Gyoo Yeol Jung 《Electrophoresis》2014,35(20):2946-2950
CE‐SSCP analysis is a well‐established DNA separation method that is based on variations in mobility caused by sequence‐induced differences in the conformation of single‐stranded DNA. The resolution of CE‐SSCP analysis was improved by using a Pluronic polymer matrix, and it has been successfully applied in various genetic analyses. Because the Pluronic polymer forms a micellar cubic structure in the capillary, it provides a stable internal structure for high‐resolution CE‐SSCP analysis. We hypothesized that formation of micellar cubic structure is influenced by the end hydroxyl group of the Pluronic polymer, which affords structural stability through hydrogen bonding. To test this hypothesis, the hydroxyl group was halogenated to eliminate the hydrogen bonding without disturbing the polarity of polymer matrix. CE‐SSCP resolution of two DNA fragments with a single base difference was significantly worse in the halogenated polymer matrices due to band broadening. The viscoelastic properties of control (which has hydroxyl group), chlorinated, and brominated F108 solution upon heating were also investigated by rheological experiments, and we found that gelation was significantly associated with resolution. In this series of experiments, the effect of the hydroxyl group in Pluronic polymer matrix on separation resolution of CE‐SSCP analysis was demonstrated. 相似文献
59.
Ir(III)‐Catalyzed C7‐Position‐Selective Oxidative CH Alkenylation of Indolines with Alkenes in Air 下载免费PDF全文
An efficient method for C7‐position‐selective alkenylation of N‐substituted indolines with alkenes is reported. Various 7‐alkenylindolines were obtained in moderate to excellent yields in air in the presence of catalytic amounts of [Cp*IrCl2]2, AgOTf, and Cu(OAc)2. The protocol relies on the use of a carbonyl or carbamoyl group on the nitrogen atom of indoline as a directing group and is potentially applicable to the synthesis of 7‐alkenylindoles and 7‐alkylindoles. 相似文献
60.
Chul-Joong Kim Hyeon-Yeol Ryu Somin Lee Han-Joo Lee Yoon-Soek Chun Jong-Kyu Kim Chang-Yeon Yu Bimal Kumar Ghimire Jae-Geun Lee 《Molecules (Basel, Switzerland)》2021,26(10)
Wild ginseng has better pharmacological effects than cultivated ginseng. However, its industrialization is limited by the inability to grow wild ginseng on a large scale. Herein, we demonstrate how to optimize ginseng production through cultivation, and how to enhance the concentrations of specific ginsenosides through fermentation. In the study, we also evaluated the ability of fermented cultured wild ginseng root extract (HLJG0701-β) to inhibit acetylcholinesterase (AChE), as well as its neuroprotective effects and antioxidant activity. In in vitro tests, HLJG0701-β inhibited AChE activity and exerted neuroprotective and antioxidant effects (showing increased catalyst activity but decreased reactive oxygen species concentration). In in vivo tests, after HLJG0701-β was orally administered at doses of 0, 125, 250, and 500 mg/kg in an animal model of memory impairment, behavioral evaluation (Morris water maze test and Y-maze task test) was performed. The levels of AChE, acetylcholine (ACh), blood catalase (CAT), and malondialdehyde (MDA) in brain tissues were measured. The results showed that HLJG0701-β produced the best results at a dose of 250 mg/kg or more. The neuroprotective mechanism of HLJG0701-β was determined to involve the inhibition of AChE activity and a decrease in oxidative stress. In summary, both in vitro and in vivo tests confirmed that HJG0701-β administration can lead to memory improvement. 相似文献