• 한국의류학회지
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• 제26권2호
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• pp.337-348
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• 2002

Based upon literature survey and questionnaire survey, this research tries to develop four new Cleanroom Garment in semiconductor industrial environment. The designs emphasize to minimize workers disconmfort so that they can not only cover human body fully but also reduce dust as much as possible during work hour in clean room. The new designs characteristics and results from both function test and dust emission test are as follows: 1. In order to reduce dust-emission, we develop new designs with hood, kimono sleeve, and back zipper. The designs with hood face positive test results in term of motion suitability and dust-omission. The design with seam in front, in particular, is effective to control dust-emission. 2. For the purpose of reducing dust-emission, we also emphasize to minimize ease of dust-proof wear, with reference to previous research and clothing experiment. The experiment participants report that the new wears are not so comfortable as existing ones, but they accept the new wears positive as effective in reducing dust-emission owing to reduced ease of Cleanroom Garment and sleeves. 3. A1so to reduce dust-emission in inner wear, we put inner wear in both Cleanroom Garments and inner wear, resulting to remove discomfort of wearers when changing clothes and of tight waist due to inner-trousers. 4. We develop new designs with elastic bands in both waist through the side lines and with velcro only at the back side. To remove twist in front contributes to reduce emission arising out of friction, also to free the appearance minding woman workers from worrying about exposed stomach. The new designs need to be accepted as a valuable alternative of Cleanroom Garment, in that they are highly effective to reduce dust-emission, which is the most important factor in the wear, in spite of some drawbacks in terms of motion-suitability, ease and appearance as shown in wearing test.

• Composites Research
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• 제17권3호
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• pp.29-37
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• 2004

본 연구에서는 대변형 보이론을 이용하여 정지 비행 시 복합재 무베어링 로우터 시스템의 공력탄성학적 안정성 해석을 수행하였다. 무베어링 로우터 시스템은 유연보, 토오크 튜브, 피치 링크, 그리고 메인 블레이드로 구성된다. 유연보, 토오크 튜브, 그리고 메인 블레이드를 각각 플랩 굽힘, 리드-래그 굽힘, 비틀림 그리고 축 방향 변형의 탄성 운동을 하는 보로 가정하고, 1차원 보 요소로 모델링을 하였다. 또한, 유연보를 복합재료 적층판으로 구성된 비틀림에 유연한 직사각형 단면을 갖는 보로 모델링 하여, 1차원 보 해석에 필요한 유효 단면 상수를 얻었다. 외력으로는 2차원 준-정상 공기력 모델을 적용하였으며, 보의 유한 요소 지배방정식은 헤밀턴 원리(Hamilton's principle)를 이용하여 얻었다. 공력 탄성학적 안정성 해석을 수행하기 위하여 p-k 방법을 이용하였으며, 유연보의 적층각과 적층 순서에 따른 구조적 연성이 무베어링 로우터 시스템의 공란성 안정성에 미치는 영향을 알아보았다.

• 한국학교보건학회지
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• 제10권2호
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• pp.193-211
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• 1997

The study was designed to gain necessary basic data in order to grasp the health knowledge, attitude, and practice level of students and teachers of elementary, middle and high schools. This study was conducted through interviews of 3,400 students and 1,022 teachers attending 14 different schools large, middle and small cities and rural towns during a period of nine months (from Oct. 2 1995 to Jun. 30 1996). By the results of this study, the recommendations can be summarized as follows: 1. A school health development committee should be established of 10 members: school health related teachers (physical trainers, nurses, and teachers in charge of health), parents, persons related to health administration, local medical doctors, and student reprensentatives in order to support and immplement school health development plans. 2. Like advanced countries, a health class of 2~4 hours should beplaced in middle and high schools. A nurse majoring in health from a university should be the teacher. 3. A curriculum of health should contain the following: education on health, sex, alcohol, tabacco, the misuse of the drugs, the structure and function of human body, the growth of the body, mental health, safety and emergency care, the prevention of disease, proper eating habits and nutrition, daily health life, family health education, society health, community health, environmental pollution and individual responsibility. 4. Create a school health promotion center, with a nurse's office, and a sports center which has health machines (bars, aerobics, training, twist machine, belt massage, running machine, bench press, chest waist, hack hip extension machine) as well as a physical strength measuring machine (muscular strength, alertness, flexibility, endurance, lung functions and so on), so that the teaching staff and students can use them and train their bodies. 5. Through a refresher education program, urge teachers to understand school health promotion services. 6. Regulate a standard and establish a system of monitoring the physical enviroment of the school (the height of desks and chairs, illumination facilities, ventilation facilities, safe drinking water). 7. Create a check list of health to evaluate improvement.

• Journal of the Korean Wood Science and Technology
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• 제37권4호
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• pp.293-299
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• 2009

섬유판을 이용한 탄화보드의 제조에 있어 무할렬 탄화법 및 탄화온도에 따른 수축률, 중량감소율 및 밀도변화에 대해 검토하였다. 섬유판을 두께별(3, 4.5, 6, 18 mm)로 준비한 후, 실험실용 탄화로를 사용하여 $400^{\circ}C{\sim}1,000^{\circ}C$의 온도조건에서 탄화보드를 제조하였다. 무할렬 탄화법은 시험편에 상하 눌림판을 설치하여 압체 탄화하는 방법을 적용하였다. 압체 탄화법에 의해 섬유판의 갈라짐과 뒤틀림 현상이 발생하지 않는 무할렬 탄화보드의 제조가 가능하였다. 탄화보드의 수축률은 길이방향 10~25%, 폭방향 12~25%, 두께방향 28~48%로 두께방향이 가장 크고 탄화온도가 상승함에 따라 커지는 경향이 나타났다. 탄화보드의 중량감소율은 섬유판의 두께에 따른 큰 차이는 나타나지 않았고 탄화온도가 상승함에 따라 커지는 경향이 나타났다. 탄화보드의 밀도는 두께 3 mm의 경질 섬유판에서 가장 컸고 탄화온도가 상승함에 따라 커지는 경향이 나타났다.

• 한국철도학회논문집
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• 제14권1호
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• pp.57-65
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• 2011

교량을 주행하는 열차의 주행안전성과 승차감의 확보를 위해 Eurocode, 신간선 기준, 호남고속철도 설계지침 등에서는 교량의 연직변위, 연직가속도, 면틀림 등의 항목으로 제한하고 있다. 그러나 이와 같은 제한 기준은 교량 설계자의 편의를 위한 간접적인 방법이다. 또한 이와 같은 기준은 일반적인 경간(Eurocode의 경우 120m 이하)에 대한 제한 기준으로서, 이 이상의 장경간 교량의 경우에는 교량/열차 상호작용 해석 등에 의한 면밀한 검토를 제안하고 있다. 본 연구에서는 교량/열차 상호작용 해석을 수행하여 열차에서의 응답을 통해 교량 상을 주행하는 열차의 주행안전성 및 승차감을 직접적으로 평가하고자 하였다. 즉, 중앙경간 300m의 현수교를 주행하는 KTX 열차에 대하여 열차 내부의 가속도와 윤중감소율을 구해 평가하는 방법을 취하였다. 또한, 이동 열차하중과 지진하중이 동시에 작용할 경우를 고려한 교량/열차/지진 상호작용해석을 수행하여 지진 시의 응답을 평가하였다.

• 대한치과보철학회지
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• 제41권3호
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• pp.360-368
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• 2003

Statement of Problem: The residual monomer of denture base materials causes hypersensitivity on oral mucosa and intereferes with the mechanical properties of the cured resin. The amount of residual monomer is influenced by materials, curing cycle, processing method, and etc. Purpose: The aim of this study was to investigate the residual methyl methacrylate(MMA) content of injection molded denture base polymer, and to compare this with the self-cured resin and the conventional compression molded heat-cured resin. Materials and Methods: Disc shaped test specimens (50mm in diameter and 3mm thick) were prepared in a conventional flasking technique with gypsum molding. One autopolymerized denture base resins (Vertex Sc. Dentimex. Netherlands) and two heat-cured denture base resins (Vertex RS. Dentimex. Netherlands, Ivocap. Ivoclar Vivadent, USA) were used. The three types of specimens were processed according to the manufacturer's instruction. After polymerization, all specimens were stored in the dark at room temperature for 7 days. There were 10 specimens in each of the test groups. 3-mm twist drills were used to obtain the resin samples and 650mg of the drilled sample were collected for each estimation. Gas chromatography (Agillent 6890 Plus Gas Chromatograph, Agillent Co, USA) was used to determine the residual MMA content of 10 test specimens of each three types of polymer. Results: The residual monomer content of injection molded denture base resins was $1.057{\pm}0.141%$. The residual monomer content of injection molded denture base resins was higher than that of compression molded heat cured resin ($0.867{\pm}0.169%$). However, there was no statistical significant difference between two groups (p>0.01). The level of residual monomer in self cured resin($3.675{\pm}0.791$) was higher than those of injection molded and compression molded heat cured resins (p<0.01). Conclusion: With respect to ISO specification pass / fail test (2.2% mass fraction) of residual monomer, injection molding technique($1.057{\pm}0.141%$) is a clinically useful and safe technique in terms of residual monomer.

• The Korean Journal of Pain
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• 제33권1호
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• pp.48-53
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• 2020

Background: The aim of this study was to clarify the topographical relationship between the accessory nerve (AN) and transverse cervical artery (TCA) to provide safe and convenient injection points for AN blockade. Methods: This study included 21 and 30 shoulders of 14 embalmed Korean adult cadavers and 15 patients, respectively, for dissection and ultrasound (US) examination. Results: The courses of the TCA and AN in the scapular region were classified into four types based on their positional relationships. Type A indicated the nerve that was medial to the artery and ran parallel without changing its location (38%). In type B (38%), the nerve was lateral to the artery and ran parallel without changing its location. In type C (19%), the nerve or artery traversed each other only once during the whole course. In type D (5%), the nerve or artery traversed each other more than twice forming a twist. At the levels of lines I-IV, the nerve was relatively close to the artery (approximately 10 mm). TCAs were observed in all specimens around the superior angle of the scapula at the level of line II, whereas they were not found below line VI. In US images of the patients, the TCA was commonly observed at the level of line II (93.3%) where all ANs and TCAs were observed in cadaveric dissection. Conclusions: The results expand the current knowledge of the relation between the AN and TCA, and provide helpful information for selective diagnostic nerve blocks in the scapular region.

• 농업생명과학연구
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• 제43권6호
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• pp.111-115
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• 2009

본 연구는 국내에서 사용되는 건조방법 (열풍, 마이크로웨이브, 진공 등)으로는 물리적 한계에 의해 건조소요에너지, 품질 저하 및 건조속도의 한계 등이 새로운 건조방식의 요구를 만족 시켜주지 못하므로, 비가열 건조를 위해 실험용 초음파 건조기를 개발하였다. 건조조건은 4수준으로 하였으며, No. 1은 초음파 및 열풍 없이 외기, No. 2는 초음파만, No. 3은 열풍만, No. 4는 초음파 및 열풍으로 총 4가지 조건으로 당근 및 인삼 절편을 건조기 내에서 30분간 건조를 하였으며, 전 후의 중량을 측정하여 건조정도를 판단하였다. 초음파 및 열풍으로 건조한 No. 4가 건감율이 가장 높았으며, 당근 절편의 건감율은 22.4% (w.b.)/h 및 인삼 절편은 3.8%(w.b.)/h로 나타났으며, 건조물의 변색 및 절편의 뒤틀림은 거의 열풍만으로 건조한 No. 3과 거의 비슷한 정도로 나타났다.

• 한국결정성장학회지
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• 제29권1호
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• pp.32-38
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• 2019

서비스디자인 방법론을 통해 사용 편의성에 중점을 둔 신개념의 모듈형 자전거 액세서리를 탄소 소재를 이용하여 개발하였다. 기존의 탄소 재질을 사용할 경우 자전거 주행 중 충격에 견디지 못하거나, 파손 현상이 발생하였으며, 이러한 문제점을 해결하고자 새로운 소재(S Foam Core 소재)를 적용 하였다. 기존 탄소 재질과 S Foam Core 소재의 강도, 뒤틀림 강도, 충격흡수 및 진동감쇄 측정을 하였고, S Foam Core가 적용된 제품이 기존 탄소 소재 보다 더 우수한 결과를 얻었다. 본 연구에서는 S Foam Core 소재로 프로토 타입을 제작하여, 자체 실험을 통해 검증하였고, 이를 보고하고자 한다.

• Structural Engineering and Mechanics
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• 제85권1호
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• pp.105-118
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• 2023

The present work is an attempt to develop a simple and accurate finite element formulation for the assessment of thermal shock/thermally induced vibrations in pretwisted and tapered functionally graded material thin (FGM) blades obtained from Voigt and local representative volume elements (LRVE) homogenization models, based on neutral surface approach. The neutral surface of the FGM blade does not coincide with its mid-surface. A finite element model (FEM) is developed using first-order shear deformation theory (FSDT) and the FGM turbine blade is modelled according to the shallow shell theory. The top and the bottom layers of the FGM blade are made of pure ceramic and pure metal, respectively and temperature-dependent material properties are functionally graded in the thickness direction, the position of the neutral surface also depends on the temperature. The material properties are estimated according to two different homogenization models viz., Voigt or LRVE. The top layer of the FGM blade is subjected to high temperature and the bottom surface is either thermally insulated or kept at room temperature. The solution of the nonlinear profile of the temperature in the thickness direction is obtained from the Fourier law of heat conduction in the unsteady state. The results obtained from the present FEM are compared with the benchmark examples. Next, the effect of angle of twist, intensity of thermal shock, variable chord and span and volume fraction index on the transient response due to thermal shock obtained from the two homogenization models viz., Voigt and LRVE scheme is investigated. It is shown that there can be a significant difference in the transient response calculated by the two homogenization models for a particular set of material and geometric parameters.