• 한국전기전자재료학회논문지
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• 제11권8호
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• pp.581-586
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• 1998

This paper describes athermally stimulated displacement current (TSDC) of arachidic acid(AA) and polyamic acid alkylamine salts(PAAS) Langmuir-Blodgett(LB) films, which is a precursor of polyimide(PI). The TSDC measurements of AA LB film were performed from temperature to about 11$0^{\circ}C$ at a rate of 0.2$^{\circ}C$/ｓ inside a vacuum chamber for a reference. And the TSDC measurements PAAS LB film were performed from room temperature to about 25$0^{\circ}C$ and temperature was increased at the same rate as that of AA LB film. They show that there are TSDC peaks at about 7$0^{\circ}C$ in the arachidic acid LB films, and at about 7$0^{\circ}C$ and 16$0^{\circ}C$ in the PAAs LB films. Results of these measurements indicate the one small peak at 7$0^{\circ}C$ is resulted from a softening of the alkyl group and the large peak at 16$0^{\circ}C$ is possibly due to dipole of C-O group in the PASS molecule. We have calculated the vertical component of the AA and PAAs L film out of the TSDC curves. It shows that the dipole moment of the AA LB film is about 70-mD at 7$0^{\circ}C$. And the dipole moment of PAAS LB film is about 040mD at 7$0^{\circ}C$ and about 200mD at 16$0^{\circ}C$ in the first measurement of TSDC. In the second measurement of TSDC of PASS LB film after cooling down to room temperature, the TSDC peaks are almost disappeared.

• Steel and Composite Structures
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• 제1권4호
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• pp.427-440
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• 2001

The growing use of unprotected or partially protected steelwork in buildings has caused a lively debate regarding the safety of this form of construction. A good deal of recent research has indicated that steel members have a substantial inherent ability to resist fire so that additional fire protection can be either reduced or eliminated completely. A performance based philosophy also extends the study into the effect of structural continuity and the performance of the whole structural totality. As part of the structural system, thermal expansion during the heating phase or contraction during the cooling phase in most beams is likely to be restrained by adjacent parts of the whole system or sub-frame assembly due to compartmentation. This has not been properly addressed before. This paper describes an experimental programme in which unprotected steel beams were tested under load while it is restrained between two columns and additional horizontal restraints with particular concern on the effect of catenary action in the beams when subjected to large deflection at very high temperature. This paper also presents a three-dimensional mathematical modelling, based on the finite element method, of the series of fire tests on the part-frame. The complete analysis starts with an evaluation of temperature distribution in the structure at various time levels. It is followed by a detail 3-D finite element analysis on its structural response as a result of the changing temperature distribution. The principal part of the analysis makes use of an existing finite element package FEAST. The effect of columns being fire-protected and the beam being axially restrained has been modelled adequately in terms of their thermal and structural responses. The consequence of the beam being restrained is that the axial force in the restrained beam starts as a compression, which increases gradually up to a point when the material has deteriorated to such a level that the beam deflects excessively. The axial compression force drops rapidly and changes into a tension force leading to a catenary action, which slows down the beam deflection from running away. Design engineers will be benefited with the consideration of the catenary action.

• 동아시아식생활학회지
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• 제26권6호
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• pp.491-497
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• 2016

The objective of this research was to determine the fermentation and quality properties of soy yogurt incorporating insoluble components fermented with Streptococcus thermophilus (S. thermophilus) and Lactobacillus bulgaricus (L. bulgaricus) for 24h. Boiled soybeans were ground and reconstituted into equivalent total solids (18%). After soymilk was homogenized with sugar, it was pasteurized in a water bath at $90^{\circ}C$ for 30 min. Two kinds of lactic acid bacteria were inoculated into two types of soymilk after cooling down $40{\sim}45^{\circ}C$ and fermentation at $37^{\circ}C$ for 24h. Titrable acidity, pH, viscosity, sugar content, and number of viable cells were determined in triplicate. Soy yogurt fermented with L. bulgaricus did not reach pH 4.5, where as S. thermophilus was considered good for achieving pH 4.08 and titratable acidity of 2.27% for 24 h. Soy yogurt fermented with S. thermophilus had a higher viscosity and lower sugar contents than that fermented with L. bulgaricusas incubation time increased. Total viable count was $1.80{\times}10^{10}CFU/mL$ on S. thermophilus and $2.16{\times}10^8CFU/mL$ on L. bulgaricus after 24 h at $37^{\circ}C$. However, there was no significant difference in sensory intensities and preference between the two samples. As a result, S. thermophilus was identified as a better culture than L. bulgaricus for the manufacture of soy yogurt incorporating insoluble components.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2010년도 한국우주과학회보 제19권1호
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• pp.37.4-37.4
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• 2010

KASI is developing the MIRIS (Multi-purpose IR Imaging System), as the main payload of Science and Technology Satellite-3 (STSAT-3). The Engineering Qualification Model (EQM) of the MIRIS has been recently fabricated, and Flight Model (FM) is now in final development stage. The system performance tests have been made mainly with EQM, and partly with FM in the laboratory, including opto-mechanics test, vibration test, thermal-vacuum test and passive cooling test down to 200K, using a thermal controlled vacuum chamber. Most of the system performance test results of the MIRIS are satisfied with the required specifications and its results were reflected in development of the FM with several revisions of the system design. In this paper, we present detailed system performance test procedures of the MIRIS and its results.

• 한국산학기술학회논문지
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• 제15권10호
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• pp.6282-6288
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• 2014

본 논문은 용접 산업현장에서 많이 사용 되는 $CO_2$ 용접에서는 차량내부 및 탱크내부 용접에서 제어 패널을 볼 수 없는 곳, 작업장이 먼 곳 등에서 용접사가 용접을 하면서 용접조건에 맞는 전류와 전압을 조절할 수가 없고, 전류와 전압을 조절하기 위해 용접을 중단하고 잦은 이동으로 용접 구조물의 순간적인 냉각에 의해 용접결함이 발생된다. 본 연구에서는 기존의 $CO_2$ 용접기 3종류를 각각 사용하여 원격제어 토치의 용접에 대해 SS400 용접구조용 압연강재를 사용하여 원격제어 토치와 기존 $CO_2$ 용접 토치를 V형 맞대기 수직자세로 용접실험을 실시하고 용접 부의 표면비드 상태의 형상을 육안검사 관찰하고 또한 이를 침투탐상검사 및 굽힘 시험을 통해 용접부의 외관품질에 대하여 중점적으로 수행하여 용접결함 감소 및 기존 상용용접기에 교체사용에 대한 성능 및 호환성여부에 미치는 영향에 대해 평가하였다.

• 한방안이비인후피부과학회지
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• 제30권1호
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• pp.87-105
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• 2017

Objectives : Atopic Dermatitis (AD) is chronic skin disease characterized by allergic hypersensitivity reactions. Saeng-ryo-Samul-tang (SRSM) can treat skin disease by cooling down blood heat, cealering away congenital fever and detoxicating. This study was conducted to investigate the effects of SRSM on AD induced by 2,4-dinitrochlorobenzene (DNCB) in mice Methods : In this study, the effects of SRSM on changes in body weights, thicknesses of dorsum skin, thicknesses and weights of ear, changes of symptoms on the dorsum skin, histopathological degree of ear and dorsum skin, IL-10 and $TNF-{\alpha}$ in serum were observed. And the effects on the proliferation rates of splenocytes were also investigated in vivo and in vitro study. Results : In SRSM topical application (Topical) group, SRSM oral application (Oral) group and SRSM Combination (Combi) group thickness of dorsum skin decreased significantly. But in TPC, ORL and CBN group, weight of ear didn't show any changes, but thickness of ear decreased significantly. And TPC, ORL and CBN group showed meaningful effectiveness symptoms like desquamation and erythema on AD's clinical espect. In histopathological observation, spongiosis, edema and inflammatory cell infiltration of epidermal were remarkably diminished in TPC, ORL and CBN group. And SRSM diminished the proliferation rates of splenocytes in vivo and vitro study. Conclusions : The present study suggests that SRSM can significantly reduced symptoms of AD, therefore SRSM is effective to treatment of AD.

• 생명과학회지
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• 제17권12호
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• pp.1739-1743
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• 2007

본 연구에서는 40대 중년여성 16명을 벨리댄스군 8명, 대조군 8명으로 구성하여 후 벨리댄스 그룹은 12주에 걸쳐 주3회 1회 60분 동안 운동을 지속적으로 실시하여 혈액성분과 골다공증, Osteocalcin을 분석한 결론은 다음과 같다. 1. WBC는 벨리댄스 그룹이 집단간, 집단내에서 유의한 감소를 나타내었다. 하지만 RBC, Hb, PLT은 모든 그룹이 집단내, 집단간 유의한 차이를 나타내지 못했다. 2. 골밀도는 벨리댄스 그룹이 집단간 유의하게 증가하였고, 집단내에서는 유의하게 증가한 것으로 나타났다. 3. Osteocalcin은 벨리댄스 그룹내 증가양상은 보였지만 유의성은 나타나지 않았다. 이상의 결과를 통해서, 벨리댄스가 WBC와 골밀도에 유익한 변화를 가져왔으며 이로 인하여 중년여성의 건강증진과 골다공증 및 골 관련 질환의 예방을 위해 큰 도움을 줄 것이며, 아직 국내에 벨리댄스에 대한 연구가 미흡한 실정이라 향후 장기간 연구가 필요할 것으로 사료된다.

• 한국산학기술학회논문지
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• 제15권5호
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• pp.3327-3335
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• 2014

본 연구에서는 천연가스의 냉각을 위한 프로판을 냉매로 사용한 단일 및 다단 냉동 사이클에 대한 소요 에너지를 비교하였다. 이를 위해서 천연가스의 온도를$ -37.00^{\circ}C$까지 냉각시키기 위해서 프로판을 냉매로 사용하여 1단 압축 및 2단, 3단, 4단 압축을 이용한 냉동 사이클에 대한 비교 연구를 수행하였다. 전산모사를 위해 한국가스공사로부터 제공받은 천연가스 조성을 적용하였으며, 열역학 모델식으로는 Peng-Robinson 상태방정식을 적용하였다. 냉동기 압축 단수가 증가할수록 응축기의 heatduty는 점점 줄어드는 것을 알 수 있었다. 4단 압축공정의 경우 1단 압축공정에 비해 응축기의 heatduty는 약 20.36% 정도 감소하였으며 냉매의 총 순환 유량은 약 14.53% 감소하였다. 또한 4단 압축공정의 경우 1단 압축공정에 비해 압축기의 총 소요 동력은 약 41.61% 감소함을 알 수 있었다.

• 기본간호학회지
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• 제14권1호
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• pp.44-52
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• 2007

Purpose: This study was done to investigate the effect of Tai Chi Qigong exercise program on insulin resistance and blood glucose in patients with type 2 diabetes. Method: This was a quasi-experimental study used a non-equivalent control group pretest-posttest design. Participants included 39 patients with type 2 diabetes mellitus patients (ages between 40-70)(experimental group, 19, control group, 20). The Tai Chi Qigong exercise program consisted of 5 minute warming up, 30-minute main exercise, and 5 minute cooling down, and was conducted twice a week for 10 weeks. The outcome variables were insulin resistance (proinsulin, C-peptide, insulin, insulin sensitivity index) and blood glucose (fasting, post prandial 2hr, HbA1c). Data was analyzed using ANCOVA, with pre-test values as covariates, to examine difference between pre and post measures between the two groups. Results: The Tai Chi Qigong was effective in lowering postprandial 2hr blood glucose. Conclusion: Twice a week 10 week-Tai Chi Qigong exercise seems to be too short to improve insulin excretion or resistance, and fasting blood sugar and HbA1C in patients with type 2 DM. A Tai Chi Qigong program at least 3 times per week or longer is recommended.

• 한국군사과학기술학회지
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• 제24권1호
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• pp.50-60
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• 2021

For conventional AESA radars, DC-DC power modules using 300 Vdc have low efficiency, high volume, heavy weight, and high price, which have problems in modularity with T/R module groups. In this paper, to improve these problems, we propose a distributed DC-DC power module with high-voltage 800 Vdc and high-efficiency Step-down Converter. In particular, power requirements for modern and future marine weapons systems and sensors are rapidly evolving into high-energy and high-voltage power systems. The power distribution of the next generation Navy AESA radar antenna is under development with 1000 Vdc. In this paper, the proposed highvoltage, high-efficiency DC-DC power modules increase space(size), weight, power and cooling(SWaP-C) margins, reduce integration costs/risk, and reduce maintenance costs. Reduced system weight and higher reliability are achieved in navy and ground AESA systems. In addition, the proposed architecture will be easier to scale with larger shipboard radars and applicable to other platforms.