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FABRICATION OF ULTRA THIN $IrO_2$-TOP-ELECTRODE FOR IMPROVING EMISSION CURRENT DENSITY IN MIM CATHODES (MIM 구조의 음극 전계 방출 효율 증진을 위한 $IrO_2$ 상부전극의 제조)

  • Park, Tae-Joo;Jung, Doo-Seok;Hwang, Cheol-Seong;Park, Min-Soo;Kang, Nam-Seok
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.07b
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    • pp.988-990
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    • 2003
  • 기존의 FED 용 MIM cathode 에 쓰이는 다층금속상부 전극을 열처리하였을 때 생기는 문제점에 대하여 살펴보았다. 먼저 열처리 후에 상부전극자체가 열변형이 일어나면서 나타나는 비저항의 증가, 표면 형상의 악화 등이 문제점으로 나타났고, 여기에 하부전극의 변형이 이러한 현상을 더욱 악화시키는 것을 확인할 수 있었다. 특히, 상부전극의 경우 그 두께가 극히 얇아 열변형이 매우 취약한 탓에 대체 물질의 개발이 시급하였다. 산화물전극은 열변형에 대해 매우 안정하여 열처리 후, 비저항이나 표면 형상의 변화가 적으며, 얇은 두께에서도 균일하게 박막이 형성되어 그 특성이 다층금속전극에 비해 매우 뛰어남을 확인하였다.

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Distances of Type II-P Supernovae SN 2014cx and SN 2017eaw

  • Kim, Sophia;Im, Myungshin;Choi, Changsu
    • The Bulletin of The Korean Astronomical Society
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    • v.43 no.1
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    • pp.31.3-32
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    • 2018
  • Supernovae (SNe) are well known as good cosmological distance probes owing to their brightness. Specifically, type Ia SNe contribute greatly to our understanding of acceleration of cosmic expansion. However, type IIP supernovae are the most common type of SNe and have been found out to a large redshift, so the application of these SNe as distance indicators is promising. IMSNG is a project for monitoring nearby galaxies (<50Mpc) to catch early light curves of transients and get inspections of their progenitors. The daily monitoring observation allows us to construct a dense light curve of SNe, too. In this talk, we present the light curves of two SNe IIP, SN 2014cx (NGC337) and SN 2017eaw (NGC6946), using our IMSNG data. A newly developed technique, the Photometric Color Method (PCM), employs only photometric data to estimate distances for SNe IIP. We present the distances to our targets measured through PCM and compare this to that of obtained via other methods.

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A Novel Maltopentaose-Producing Amylase as a Bread Antistaling Agent

  • Auh, Joong-Hyuck;Lee, Su-Yong;Yoo, Seung-Seok;Son, Hyun-Ju;Lee, Jae-Woo;Lee, Sung-Joon;Kim, Young-Bae;Park, Kwan-Hwa
    • Food Science and Biotechnology
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    • v.14 no.5
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    • pp.681-684
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    • 2005
  • A maltopentaose-producing amylase (G5-amylase) from Bacillus megaterium KSM B-404 was applied to retard bread retrogradation. Retrogradation rates were determined by differential scanning calorimetry. Gel permeation chromatography determined changes in maltooligosaccharide composition and the molecular weight profiles of carbohydrate tractions. The baking process produced maltopentaose and maltotriose by the hydrolysis of starch molecules into small units. Amylose and amylopectin degradation as well as maltooligosaccharides produced by the enzyme were likely responsible for retarding starch retrogradation. Overall, addition of G5-amylase reduced the starch retrogradation rate, and was as effective as Novamyl(R), a commercial enzyme.

Chemical Lithography by Surface-Induced Photoreaction of Nitro Compounds

  • Han, Sang-Woo;Lee, In-Hyung;Kim, Kwan
    • ETRI Journal
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    • v.26 no.1
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    • pp.38-44
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    • 2004
  • Searching for systems of self-assembled monolayers (SAMs) that can be used as templates for chemical lithography, we found that nitro groups on aromatic SAMs are selectively converted on Ag to amino groups by irradiation with a visible laser. 4-nitrobenzenethiol on Ag was thus converted to 4-aminobenzenethiol by irradiating it with an $Ar^+$ laser. This was evident from surface-enhanced Raman scattering (SERS) as well as from a coupling reaction forming amide bonds. The surface-induced photoreaction allowed us to prepare patterned binary monolayers on Ag that showed different chemical reactivities. Using the binary monolayers as a lithographic template, we induced site-specific chemical reactions, such as the selective growth of biominerals on either the nitro- or amine-terminated regions by adjusting the crystal-growth conditions. We also demonstrated that patterned, amine-terminated monolayers can be fabricated even on gold by using silver nanoparticles as photoreducing catalysts.

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RT-PCR Detection of dsRNA Mycoviruses Infecting Pleurotus ostreatus and Agaricus blazei Murrill

  • Kim, Yu-Jeong;Park, Sang-Ho;Yie, Se-Won;Kim, Kook-Hyung
    • The Plant Pathology Journal
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    • v.21 no.4
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    • pp.343-348
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    • 2005
  • The partial nucleotide sequences of the genomic dsRNA mycoviruses infecting Pleurotus ostreatus (isolates ASI2596, ASI2597, and Bupyungbokhoe) and Agaricus blazei Murrill were determined and compared with those of the other dsRNA mycoviruses. Partial nucleotide sequences of the purified dsRNA from ASI2596 and ASI2597 revealed RNA-dependent RNA polymerase sequences that are closely related to Oyster mushroom isometric virus 2, while nucleotide sequences and the deduced amino acid sequence from dsRNA mycovirus infecting Agaricus blazei did not show any significant homology to the other dsRNA mycoviruses. Specific primers were designed for RT-PCR detection of these dsRNA viruses and were found to specifically detect each dsRNA virus. Northern blot analysis confirmed the homogeneity of RT-PCR products to each purified dsRNA. Altogether, our results suggest that these virus-specific primer sets can be employed for the specific detection of each dsRNA mycovirus in infected mushrooms.

Transformation of Coprinus congregatus with a Linearized Plasmid Vector to Phosphinothricin Resistance (Coprinus congregatus에서 선형으로 전환한 plasmid DNA를 사용하여 phosphinothricin 저항성에 대한 형질전환)

  • Leem, Young-Eun;Kim, Soon-ja;Choi, Hyoung-Tae
    • Korean Journal of Microbiology
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    • v.33 no.4
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    • pp.274-276
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    • 1997
  • Transformation of Coprinus congregatus with a linearized plasmid has been successfully carried out using phosphinothricin resistance gene as a dominant selectable marker. The transforming frequency was about 500 transformants per microgram of DNA using the protoplast-$CaCl_2$ method. The transforming vector pBARGEM 7-1 which had the phosphinothricin resistance gene was detected in the restriction enzyme fragments of chromosomal DNA from a transformant by Southern hybridization.

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Clinical Outcome of Transfer of Cryopreserved-Thawed Embryos Obtained after Intracytoplasmic Sperm Injection: Comparison with Conventional In Vitro Fertilization (난자 세포질내 정자 주입술 후 동결보존 배아이식: 고식적 체외수정시술과의 비교 연구)

  • Kim, S.H.;Jee, B.C.;Jung, B.J.;Kim, H.S.;Ryu, B.Y.;Pang, M.G.;Oh, S.K.;Shon, C.;Suh, C.S.;Choi, Y.M.;Kim, J.G.;Moon, S.Y.;Lee, J.Y.
    • Clinical and Experimental Reproductive Medicine
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    • v.24 no.3
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    • pp.281-292
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    • 1997
  • The objective of this study was to compare retrospectively the survival and pregnancy rates(PR) of cryopresered-thawed embryos obtained from intracytoplasmic sperm injection (ICSI) or conventional in vitro fertilization (IVF). Ninety-six cycles of cryopresered-thawed embryo transfer (ET) were performed in 79 patients from June, 1996 to September, 1997 and grouped as followings: 20 cycles (16 patients) inseminated by ICSI (ICSI Group) and 76 cycles (63 patients) by conventional IVF (IVF Group). Slow-freezing and rapid-thawing protocol was used with 1.5M propanediol (PROH) and 0.1M sucrose as cryoprotectant. All embryos were frozen-thawed at the two pronuclear (2 PN) stage excluding four cycles in which the early cleavage stage embryos were frozen, and allowed to cleave in vitro for one day before ET. The duration from freezing to thawing was comparable in both groups ($mean{\pm}SD$, $112.1{\pm}80.0$ vs. $124.8{\pm}140.1$ days). The age of female ($31.2{\pm}3.4$ vs. $32.6{\pm}3.3$ years) and the endometrial thickness prior to progesterone injection ($9.4{\pm}2.0$ vs. $9.3{\pm}1.8$ mm) were also comparable in both groups. There was no significant difference in the outcomes of cryopreserved-thawed ET between two groups: survival rate ($85.2{\pm}16.1%$ vs. $82.2{\pm}19.7%$), cleavage rate ($96.9{\pm}6.7%$ vs. $94.7{\pm}13.0%$), cumulative embryo score (CES, $54.5{\pm}31.1$ vs. $49.0{\pm}20.0$), preclinical loss rate (5.0% vs. 5.3%), clinical miscarriage rate (0% vs 29.4%), clinical PR per transfer (35.0% vs. 22.4%), implantation rate (9.9% vs. 5.6%), and multifetal PR (42.9% vs. 17.6%). In conclusion, human embryos resulting from ICSI can be cryopreserved-thawed and transferred successfully, and the survival rate and PR are comparable to conventional IVF.

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A study on lightening the weight of an induction motor satisfying maximum power rating (순시 정격을 고려한 유도기 경량화에 관한 연구)

  • Park, Jeong-Tae;Lee, Cheol-Gyun;Kim, Joung-Koo;Jung, Hyun-Kyo;Won, Jong-Soo
    • Proceedings of the KIEE Conference
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    • 1994.07a
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    • pp.162-164
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    • 1994
  • This paper presents the optimal design method of an induction motor for electric vehicle which minimizes the weight of motor and satisfies maximum power rating at the same time. Effects of motor parameters on the dimensions and weight of motor is investigated. Optimal routine which is used in this paper is simulated annealing technique.

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