• 공업화학
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• 제27권6호
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• pp.612-619
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• 2016

폐 LCD 판넬로부터 회수된 폐 붕규산유리를 이용하여 흡음특성을 갖는 알루미늄 함유 붕규산유리발포체의 제조 가능성을 조사하였다. 입도 325 mesh 이하의 크기로 분쇄 조절된 폐 붕규산유리분말 100 g에 대해 발포제로서 탄소분을 0.3중량 분율, $Na_2CO_3$, $Na_2SO_4$, $CaCO_3$를 각각 1.5중량 분율, 기공조절제로서 $H_3BO_3$ 및 $Al_2O_3$를 각각 6.0 및 3.0 중량분율이 되도록 첨가한 원료 유리분말을 발포소성온도 $950^{\circ}C$에서 20 min간 발포를 진행함으로서 개기공률 45%를 갖는 발포체를 제조하였으며 이 경우 흡음률 0.5~0.7의 흡음 특성을 갖고 있음을 보여 주었다. 아울러 이 흡음성능을 지닌 알루미늄 함유 붕규산유리발포체는 밀도 $0.21g/cm^3$, 굽힘강도 $55N/cm^2$ 이상, 압축강도 $298N/cm^2$ 이상의 우수한 물성을 가지고 있어 다양한 용도에 내화학성 및 내열성의 흡음체로 사용될 수 있다.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2007년도 The 1st International Symposium on Advanced Magnetic Materials
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• pp.297.1-297.1
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• 2007

• 대한바이러스학회지
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• 제28권1호
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• pp.11-20
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• 1998

Twenty isolates of Hantavirus were isolated from patients and reserovirs from 1988 to 1994 in Korea. Isolation rate was 1.9% (10/538) in patients, 6.2% (5/81) in Apodemus sp., 2.6% (1/38) in Rattus sp. and 0.6% (4/677) in bats. Reciprocal mean IFA titers ranged from 27.5 to 1,024 at the specimen collection. According to the growth rate and reaching peak titier of infectivity, the isolates were grouped as rapid, intermediate, and slow growing groups. All isolates were confirmed as Hantaan type by the nested RT-PCR on the G1 region of the M segment. Comparison of nucleotide sequence (Nt: 2101 - Nt: 2280) of the G2 region revealed that the sequence homology bewteen Hantaan 76/118 virus and the isolates was more than 90%. Several nucleotide positions of the isolates showed high variation. The variation rate of patientisolates was about one-half when compared with that of rodentisolates. On the basis of phylogenetic analysis Hantaan viruses isolated were divided into two genogroups. These results indicate that Hantaan virus is highly dominant serotype in Korea and the virologic property and genogroup are not correlated.

• 한국조리학회지
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• 제16권4호
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• pp.297-304
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• 2010

머루 주스의 총 안토시아닌 함량은 $17.0{\pm}0.1$, 색도는 $33.9{\pm}1.4$였으며, 총 페놀과 플라보노이드의 함량은 각각 $25.4{\pm}3.1$ mg/l00 g, $4.4{\pm}1.4$ mg/100 g이었다. 무기질은 특히 K의 함량이 $11.3{\pm}0.3$ mg/100 g으로 가장 높은 함량을 보였다. 전자공여능을 측정한 결과 $1,000\;{\mu}L$/mL의 농도에서 $94.8{\pm}1.2%$의 뛰어난 전자공여능을 보였다. 머루 주스를 이용하여 금속이온의 환원력을 측정한 결과, 농도가 $1,000\;{\mu}L$/mL일 때 환원력은 1.134를 나타내었다. 그리고 아질산염에 대한 소거능을 측정한 결과, pH 1.2의 조건일 때 $1,000\;{\mu}L$/mL의 농도에서 $77.1{\pm}1.1%$로 가장 뛰어난 소거능을 보였다. 머루 주스의 농도가 증가함에 따라 실험 결과는 유의적으로 증가하는 경향을 보였다.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제23권1호
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• pp.13-19
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• 2016

In this paper, we study some characterizations of unbounded domains. Among these, so-called G-domain is introduced by Cabre for the Aleksandrov-Bakelman-Pucci maximum principle of second order linear elliptic operator in a non-divergence form. This domain is generalized to wG-domain by Vitolo for the maximum principle of an unbounded domain, which contains G-domain. We study the properties of these domains and compare some other characterizations. We prove that sA-domain is wG-domain, but using the Cantor set, we are able to construct a example which is wG-domain but not sA-domain.

• 폴리머
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• 제24권3호
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• pp.306-313
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• 2000

Stannous 2-ethylhexanoate와 2-hydroxyethyl methacrylate (HEMA)를 개시제로 사용하여 $\varepsilon$-caprolactone을 개환중합하여 polycaprolactone (PCL) 거대단량체를 합성하였다. 합성된 PCL 거대 단량체는 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO)를 개시제로 사용하는 안정한 자유 라디칼 중합에 의해 스티렌과 공중합되었으며 그 결과 분자구조가 조절된 poly(styrene-g-caprolactone) (PS-g-PCL)이 얻어졌다. 얻어진 공중합체는 광산란 검출기가 장착된 GPC를 이용하여 분자량을 측정하였으며, $^1$H-NMR 분석을 통해 공중합체내의 PS/PCL 함량 비를 구하였다. 전체 분자량과 PCL 거대단량체의 분자량 그리고 공중합체내 PCL의 함량으로부터 사슬당 그라프트의 수를 계산하였다. DSC를 이용한 그라프트 공중합체의 열분석에서 PCL 결정의 흡열 피이크가 관찰되었으며, 이로부터 PS-g-PCL이 상분리되어 있음을 확인하였다.

• 대한산업공학회지
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• 제28권2호
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• pp.187-192
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• 2002

In this paper we consider an M/G/1 queueing system with vacation. The length of vacation period may be controlled by the waiting time of the first customer. The server goes on vacation as soon as the system is empty, and resumes service either when the waiting time of the leading customer reaches a predetermined value, or when the vacation period is expired, whichever comes first. We consider two types of vacation, say, multiple vacation type and N-policy type. We derive the steady-state distributions of the number of customers at arbitrary time and arbitrary customer's waiting time by means of decomposition property. Also, the mean lengths of busy period, idle period and a cycle time are given.

• 대한수학회지
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• 제53권1호
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• pp.1-17
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• 2016

Let $\mathcal{W}$ be an additive full subcategory of the category R-Mod of left R-modules. We provide a method to construct a proper ${\mathcal{W}}^H_C$-resolution (resp. coproper ${\mathcal{W}}^T_C$-coresolution) of one term in a short exact sequence in R-Mod from those of the other two terms. By using these constructions, we introduce and study the stability of the Gorenstein categories ${\mathcal{G}}_C({\mathcal{W}}{\mathcal{W}}^T_C)$ and ${\mathcal{G}}_C({\mathcal{W}}^H_C{\mathcal{W}})$ with respect to a semidualizing bimodule C, and investigate the 2-out-of-3 property of these categories of a short exact sequence by using these constructions. Also we prove how they are related to the Gorenstein categories ${\mathcal{G}}((R{\ltimes}C){\otimes}_R{\mathcal{W}})_C$ and ${\mathcal{G}}(Hom_R(R{\ltimes}C,{\mathcal{W}}))_C$ over $R{\ltimes}C$.

• Carbon letters
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• 제25권
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• pp.103-112
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• 2018

Hierarchically porous, chemically activated carbon materials are readily derived from biomass using hydrothermal carbonization (HTC) and chemical activation processes. In this study, empty fruit bunches (EFB) were chosen as the carbon source due to their sustainability, high lignin-content, abundance, and low cost. The lignin content in the EFB was condensed and carbonized into a bulk non-porous solid via the HTC process, and then transformed into a hierarchical porous structure consisting of macro- and micropores by chemical activation. As confirmed by various characterization results, the optimum activation temperature for supercapacitor applications was determined to be $700^{\circ}C$. The enhanced capacitive performance is attributed to the textural property of the extremely high specific surface area of $2861.4m^2\;g^{-1}$. The prepared material exhibited hierarchical porosity and surface features with oxygen functionalities, such as carboxyl and hydroxyl groups, suitable for pseudocapacitance. Finally, the as-optimized nanoporous carbons exhibited remarkable capacitive performance, with a specific capacitance of $402.3F\;g^{-1}$ at $0.5A\;g^{-1}$, a good rate capability of 79.8% at current densities from $0.5A\;g^{-1}$ to $10A\;g^{-1}$, and excellent life cycle behavior of 10,000 cycles with 96.5% capacitance retention at $20A\;g^{-1}$.

• 한국염색가공학회지
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• 제22권1호
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• pp.43-50
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• 2010

The thermal treatment for carbon nanotube was applied to remove the water, metal catalyst and other impurities in carbon nanotube. The surface of carbon nanotube was changed into open structure with acid treatment by mixed solution of $HNO_3$ and $H_2SO_4$. The dispersion property of the functionalized and modified carbon nanotube was assessed with naked eyes by dispersing it in DMF. Carbon nanotube mixd polyurethane film was made to estimate the dispersion property by reflectance of the film with UV-Vis spectrometer. Also the internal structure of carbon nanotube was observed with SEM and TEM and thermal pyrolysis property of the carbon nanotube was measured by TGA and DSC. The surface modification of carbon nanotube by thermal and acid treatments improved the dispersion property of carbon nanotube/polyurethane mixed materials.