• 대한임상검사과학회지
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• 제37권1호
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• pp.41-46
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• 2005

It is known that mast cells (MCs) are increased in H. pylori-infected gastritis and its increase is mediated by stem cell factor (c-kit ligand). To determine the mechanism of mast cell recruitment and activation by stem cell factor, weinvestigated the expression of stem cell factor receptor (c-kit) in H. pylori-positive and -negative gastric mucosa. Biopsy specimens from 16 H. pylori-negative and 20 positive subjects were examined. H. pylori infection in gastric mucosa was examined by the Warthin-Starry method. MC and c-kit were identified by immunohistochemisty, using a monoclonal antihuman MC tryptase antibody and a polyclonal anti-human c-kit antibody. Densities of MC and c-kit positive cell were measured by a computerized image analysis system. MCs were detected in the lamina propria of both H. pylori-positive and -negative gastric mucosa. Densities of MC and c-kit positive cell were significantly greater in H. pylori-positive than -negative subjects. c-kit was located on the surface of MCs. These results indicate that stem cell factors may be one of the factors involved in mast cell increase and that they activate mast cells by binding with c-kit.

• 동력기계공학회지
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• 제12권3호
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• pp.12-18
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• 2008

In the present study, the numerical simulation has been performed to investigate K-factor for temperature variation of working fluid in spray nozzle with orifice. The commercial CFD software, Fluent with the proper modeling was applied for analyzing the internal of the spray nozzle. Numerical result for K-factor at $20^{\circ}C$ agrees with the experimental result that it applied n=0.5 within about 7% error. The pressure drop inside nozzle is showed 20% passing swirler, 70% in the region between the outlet of swirler and the orifice and 10% at the outlet of orifice. As the operating pressure is increased, K-factor is decreased by effect of flow resistance at it's inlet before pass swirler. The temperature increase of working fluid reduced the flow rate according to reducing of density, and average 1.23% decrease is showed in the present research.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.147-150
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• 2002

HPSL(High Pressure Sodium lamp)have attracted much attention in recent years, because they offer high luminous efficiency and very long life. Recently, AC-DC converters have been widely as power factor improvement circuits in the power conversion equipment An application of the ZVT-PWM(Zero Voltage Transition Pulse Width Modulation) boost converter, which has great advantage on miniaturization and high power density, to the power factor improvement circuit of the HPSL inverter are described to identify the power factor correction characteristics of the inverter. In this paper the series-parallel resonant inverter(electronic ballast) for driving a HPS lamp is discussed. Finally, a power factor corrector is cascaded in front of the electronic ballast. Consequently, a high power factor above 0.99 and low THD on the line current can be achieved.

• 멤브레인
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• 제14권4호
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• pp.312-319
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• 2004

졸겔법에 의해 Si(OC$_2$$H_5$/)$_4$-($CH_3$O)$_3$B-C$_2$$H_5$OH-$H_2O$계로부터 다공성의 SiO$_2$-B$_2$O$_3$ 막을 제조하였다. SiO$_2$-B$_2$O$_3$막의 특성을 BET, IR spectrophotometer, X-ray diffractometer, SEM 과 TEM을 사용하여 조사하였다. $700^{\circ}C$에서 얻어진 SiO$_2$-B$_2$O$_3$ 막의 평균 기공직경은 0.0048 $\mu\textrm{m}$이고, 표면적은 354.398 $m^2$/g이었으며, 입자의 크기는 7 nm인 무정형의 다공체이었다. SiO$_2$-B$_2$O$_3$ 막의 수소/질소 혼합 기체 분리 특성은 기체분리 압력을 달리하여 조사하였다. $25^{\circ}C$, ΔP 155.15cmHg에서 수소/질소 혼합 기체를 분리하여 본 결과 SiO$_2$-B$_2$O$_3$ 막의 수소에 대한 real separation factor($\alpha$)는 4.68이었다. 그리고 투과셀의 압력차(ΔP)값이 증가할수록 real separation factor($\alpha$), head separation factor($\beta$), tail separation factor((equation omitted))값이 증가하였다.

• 한국산학기술학회논문지
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• 제14권12호
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• pp.6542-6549
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• 2013

콘크리트 구조물이 대형화됨에 따라 고교각, 장지간의 보 등 부재가 장대화되고 있으며, 장지간의 철근콘크리트 부재에서는 자중을 줄이고 강성을 증가시키기 위해 속빈 단면을 사용하는 것이 증가하는 추세이다. 본 연구에서는 철근콘크리트 속빈 단면 보의 모멘트-곡률 관계를 해석적 방법으로 구하여 속빈 부분의 크기, 상부플랜지와 복부의 철근 배치조건이 부재의 휨거동 및 곡률연성지수에 미치는 영향을 분석하였다. 속빈 부분의 크기($b_i/b_o$ 또는 $h_i/h_o$)가 0.5이하일 때에는 곡률연성지수가 일정하게 유지되며, 0.7이상이 되면 곡률연성지수가 급격히 감소하였다. 또한, 복부에 철근을 배치하면 곡률연성지수가 감소하며 단철근 보에서와 같은 수준의 연성지수를 얻기 위해서는 복부에 배치한 철근과 같은 양을 상부플랜지에 배치해야 하는 것으로 나타났다.

• 한국전자거래학회지
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• 제22권2호
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• pp.19-38
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• 2017

스마트폰 비즈니스 환경이 H/W 중심에서 S/W 경쟁으로 변화하고 있고 기업의 경쟁기반도 H/W에서 서비스로 패러다임이 변화하고 있다. 이에 본 연구에서는 스마트폰 비즈니스 구성요인을 H/W, S/W, 통신서비스로 구성하였다. 본 연구의 목적은 비니지스 구성요인이 고객만족과 고객충성도에 미치는 영향관계를 파악하고, 전환비용이 고객충성도에 미치는 영향을 분석하는 것이다. 연구분석 결과, 고객 만족에 유의한 영향을 미치는 요인은 H/W 요인임이 밝혀졌고, S/W 요인과 통신서비스는 영향을 미치지 않는 것으로 확인되었다. 고객층성도에 영향을 미치는 요인은 H/W 요인과 S/W 요인임이 입증되고 통신서비스는 영향을 미치지 않는 것으로 분석되었다. 고객만족이 H/W 요인과 고객충성 간에 매개역할을 하는 것으로 나타났다. 전환비용은 선행연구와 동일하게 고객충성도에 유의한 영향을 미치는 것으로 분석되었다. 본 연구가 기존의 연구와의 차별점은 기존의 연구가 H/W, S/W, 통신서비스를 각각 나누어 분석하였으나, 본 연구에서는 H/W, S/W, 통신서비스의 통합된 3차원이 고객만족과 고객충성도에 미치는 영향을 규명하였다는데 의의가 있다. 본 연구 결과는 학술적, 실무적으로 성장이 정체된 스마트폰 산업에 시사점을 제공할 수 있으리라 본다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.1302-1308
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• 2010

This study the change of the safety factor before and after the reinforcement were compared by performing the parameter research based on the limit equilibrium analysis regarding the same cross section after carrying out the safety factor before the reinforcement on the virtual section in order to observe the change of the safety factor of the slop reinforced with the slope planting reinforced earth, and the variation of the safety factor according to the increase of the length of the reinforcement materials and the change of the slope height was analyzed. As the result, the reinforcement effect was insignificant at no more than 0.6 of L/H, the reinforcement length ratio when the reinforcement length was increased, as the increase of the safety factor was slow comparing with the non-reinforced slope. At 3.0m of the slope height, reinforcement on the slope is not necessary, and at 3.0m to 5.0m of the slope height, the inclination was not influencing at no less than 0.6 of L/H. At 5.0m to 9.0m of the slope height, the safety factor was mostly secured on the slope at 0.8 of L/H and the over-reinforced slope appeared at no less than 1.0 of L/H. Also, the safety factor increased as the slope height increases and the slope gets steeper till 0.8 of L/H, but the slope steepness affects more on the increase of the safety factor than the reinforcement material, as the reinforcing force by the reinforcement material became steady.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2001년도 추계학술발표대회
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• pp.447-448
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• 2001

Human garnulocyte-colony stimulating factor(hG-CSF), a hematopoietic growth factor$^{1)}$, was produced and secreted from tobacco cell suspension. hG-CSF produced from tobacco cell suspension culture is biologically active form. The produced amount of hG-CSF is about 100${\mu}g/L$ in 9 days after inoculation.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제13권1호
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• pp.49-61
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• 2009

In this paper some attempts have been made: (a) To identify all the elementary minor concepts of the Highest Common Factor (H.C.F.) and the Lowest Common Multiple (L.C.M.), and (b) To find the sequential order of these elementary concepts. Total 385 elementary minor concepts have been identified and sequenced.

• 한국식품영양과학회지
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• 제20권5호
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• pp.494-502
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• 1991

Diazotized chitin(CHITN) as supports of immobilized enzyme, which was obtained by alkaline hydrolysed chitin with NaN3 and HCI was employed to produce CHITN-Gase with glutaraldehyde as bifunctional reagent. Activities of CHITN-Gase were determined with reaction of p-nitro-pheol-$\beta$-D-glucopyranoside(PNG) in plug flow reactor as a reference of CHITA-Gase. Their optimum temperature, pH, Km and Vmax, mass transfer coefficient (h), effctiveness factor(η)were plotted with variation of flow rate and H/D. Mass transfer coefficient(h) of those enzymes increased because of their flux, as flow rates were increased and controlled by reaction rate. Effectiveness factor(η) of both enzymes were nearly 1.0.