• 대한정형외과학회지
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• 제53권6호
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• pp.490-497
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• 2018

목적: 65세 이상 노인 환자들을 대상으로 세라믹 대퇴 골두 및 교차결합 폴리에틸렌 라이너를 인공 관절면으로 사용한 무시멘트형 인공 고관절 전치환술의 최소 5년 이상 임상 및 방사선 추시 결과들을 분석하여 세라믹-폴리에틸렌 관절면의 유용성 여부를 알아보고자 하였다. 대상 및 방법: 2010년 3월부터 2012년 9월까지 65세 이상 노인 환자 51명(56 고관절)을 대상으로 후향적 연구를 진행하였다. 평균 연령은 $70.9{\pm}5.1$세였다. 임상 평가는 Harris hip score를 이용하였고, 방사선 평가는 비구 컵 경사각 및 전염각, 대퇴 스템 정렬 상태, 마모를 측정하였다. 수술 후 합병증 발생 유무도 조사하였다. 결과: 임상 평가상 Harris hip score는 수술 전 평균 48점에서 최종 추시 시 평균 87점으로 향상되었다(p<0.05). 방사선 평가상 평균 비구 컵 경사각은 $40.9^{\circ}{\pm}6.4^{\circ}$, 평균 비구 컵 전염각은 $20.3^{\circ}{\pm}8.1^{\circ}$였다. 거상 라이너를 사용한 16예에서 평균 비구 컵 전염각은 $14.3^{\circ}{\pm}7.9^{\circ}$, 중립 라이너를 사용한 40예에서 평균 비구 컵 전염각은 $22.4^{\circ}{\pm}9.1^{\circ}$였다(p<0.05). 평균 대퇴 스템 정렬각은 $0^{\circ}$도(범위, 내반 $4^{\circ}$-외반 $4^{\circ}$)였다. 평균 선상 마모량은 $0.458{\pm}0.041mm$였으며 평균 연간 선상 마모율은 $0.079{\pm}0.032mm/yr$였다. 수술 후 합병증으로 대퇴 스템 주위 골절 6예(10.7%)가 발생하였다. 결론: 본 연구 결과 분석상 탈구나 세라믹-폴리에틸렌 관절면에서 기인한 합병증이 없으므로 65세 이상 노인 환자에서 무시멘트형 인공 고관절 전치환술 시행 시 세라믹-폴리에틸렌 관절면을 유용하게 사용할 수 있으나 수술 중 대퇴 스템 주위 골절 발생을 방지하기 위한 좀 더 세심한 노력이 필요하다.

• 한국안광학회지
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• 제21권1호
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• pp.23-34
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• 2016

목적: 본 연구에서는 써클콘택트렌즈의 착용이 시력교정술을 받은 눈에서의 대비감도 및 눈부심감도에 미치는 영향을 알아보고자 하였다. 방법: 시력교정술을 받지 않은 40안과 시력교정술을 받은 30안에 무도수의 써클콘택트렌즈를 착용시킨 후 CGT-1000을 이용하여 대비감도와 눈부심감도를 평가하였으며, 동공크기를 측정하여 대비감도 및 눈부심감도와 동공크기와의 상관관계를 분석하였다. 결과: 시력교정술을 받은 경우 써클콘택트렌즈 착용으로 고영역대 공간주파수에서는 대비감도의 저하가 나타났으며 시력교정술을 받지 않은 군보다 그 정도가 더 크게 나타났다. 써클콘택트렌즈 착용으로 인해 동공크기와 대비감도 변화와의 상관성이 작아졌으며 시력교정술을 받은 군에서 상관성이 더 작아졌다. 또한, 써클콘택트렌즈 착용은 눈부심에 더 크게 영향을 미치는 것으로 나타났으며, 동공크기에 따른 눈부심감도의 변화분석에서도 시력교정술을 받지 않은 군에서 눈부심을 더 크게 느끼는 것으로 나타났다. 시력교정술을 받은 각막에서의 써클콘택트렌즈는 각막의 중심부에 위치하지 못하였다. 결론: 본 연구에서는 시력교정술 후 써클콘택트렌즈 착용으로 인해 대비감도가 저하되며 눈부심이 증가되므로 이에 대한 충분한 이해와 고려가 필요함을 제안한다.

• Restorative Dentistry and Endodontics
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• 제20권1호
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• pp.193-213
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• 1995

The purpose of this study is to investigate a possible contribution of nonspecific esterases, which occur in the oral cavity, to the degradation of ester bonds in polymethacrylates. One of the problems connected with the use of composite resins for restorations is their inadequate resistance to wear. It has been shown that methacrylate hydrolysis can be catalyzed by enzymes and that a carboxylic hydrolase (porcine liver esterase) catalyzed the hydrolysis of several mono - and dimethacrylates. The softening effect on a BISGMA/TEGDMA polymer induced by hydrolase will accelerate the in vivo wear of the polymer. Porcine liver esterase (EC 3.1.1.1) 3.2 mol/L $(NH_4)_2$ $SO_4$ was obtained from Sigma Chemical Company. The esterase activity of one unit is defined as the amount of enzyme capable of hydrolyzing $l{\mu}mol$ ethyl butyrate per min at pH 8.0 AT $25^{\circ}C$. Phosphate buffer, 10mmol/L, pH 7.0, was made by adjustment of a solution of $Na_2HPO_4$ with $H_3PO_4$. Composite resins used in this study are Silux Plus, Z-100, Durafil VS, and Prisma APH. Cylindrical specimens, 14mm in diameter and 3mm thick, of Silux Plus, Z-100, Durafil VS, Prisma APH were polymerized under the celluloid strip. 60 specimens were divided into 2 groups. One group was emersed only in buffer solution, the other group was emersed in buffer and enzyme solution. Silux Plus and Z-100 were divided into 2 subgroups, one subgroup was cured only Visilux 2. And the other subgroup was cured Visilux 2 and Triaid II. Thereafter, specimens were polished to its best achievable surface according to manufacture's directions. The Vickers hardness of the specimens was measured after 1, 2, 4, 7, 9, 15, 50 days. The solutions were changed after each measurement. Composite resin surfaces were evaluated for the surface roughness with profilometer (${\alpha}$-step 200, Tencor instruments, USA) after 1 and 50 days. And then surfaces of specimens were pictured with stereosopy after 1 and 50 days. The results were as follows. 1. The surface hardness of Silux plus, durafil VS, and Prisma APH were decreased with time. But, the surface hardness of Z-100 was not decreased. 2. The surface hardness of all composite resins was decreased by esterase. 3. Composite resins, which were light-cured by Visilux 2 and concomitantly baked by oven, showed more hardened surface than light-cured by Visilux 2 only. 4. Significant surface changes were occured in Silux plus after esterase treatment.

• 한국재료학회지
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• 제1권4호
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• pp.221-228
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• 1991

본 연구는 computerdisk drive와 VTR head에 사용되어 지고 있는 ferrite head cores의 gap 형성에 적합한 유리의 봉착특성에 관하여 고찰하였다. 유리의 특성측정은 열팽창 계수, 미세경도, 내마모성을 측정하였으며 계면에서의 원소 농도분포는 WDS에 의해 관찰하였고 젖음성은 고온 현미경으로 측정하였다. 그 결과는 다음과 같다. 1. $PbO-B_2O_3$계 봉착용 유리에 있어서 PbO의 함량이 증가함에 따라 열팽창계수와 마모량이 증가하였으며 $B_2O_3$함량이 증가함에 따라서는 열팽창계수와 마모량이 감소하였다. 2. $PbO-B_2O_3$계 유리에 있어서 contact angle은 PbO함량에 주로 영향을 받는다. 3. 열팽창계수의 증가에 따라 봉착온도는 비례적으로 낮아지는 경향을 나타내었다. 4. Mn-Zn single crystal ferrite와 $PbO-B_2O_3$계 봉착용유리의 융착 계면에서의 확산은 ferrite성분이 glass측으로 소량확산이 이루어졌으며 봉착 열처리 시간에 따라서는 거의 영향을 받지 않았다.

• 복식
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• 제64권2호
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• pp.1-16
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• 2014

The purpose of this study was to examine the differences of the satisfaction with school uniforms according to demographic variables and to investigate the causal relations of parental control, school life satisfaction, and demographic variables to the satisfaction with school uniform. The research method was a survey method using a questionnaire. The subjects were 407 high school students (191 male, and 216 female) residing in Seoul and the suburbs of Seoul. Students were very satisfied with the convenience of not having to choose what to wear every morning, but the satisfactions with uniform cost and design were lower. The aesthetic, psychological, and status symbol satisfaction of school uniforms were higher as parents and adolescents had more communication, and the psychological and status symbol satisfaction of school uniforms were higher as the level of parental supervision for adolescents was higher. The female students had higher psychological satisfaction with school uniforms than the male students were. The aesthetic satisfaction of school uniforms was lower as mother's education level was higher. The adolescents from upper class families had lower aesthetic, psychological, and status symbol satisfaction with school uniforms than the adolescents from middle and lower class families. The satisfaction with school uniform was influenced by school life satisfaction the most, and the next in the order by grade (-), the social class (-), and the communication with parents. The factors that influenced school life satisfaction for students were parental supervision, school records, the discipline consistency of parents, and their communication with their parents. Therefore, the 4 variables had indirect effect on the satisfaction with school uniform through school life satisfaction.

• 마이크로전자및패키징학회지
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• 제22권4호
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• pp.47-56
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• 2015

본 논문에서는 HDI(High Density Interconnection) 기판의 코어로 사용될 수 있는 카본 CCL(Copper Claded Layer)의 열거동 및 신뢰성 특성을 실험과 CAE를 이용한 수치해석을 통해 평가하였다. 카본 CCL의 특성평가를 위해 기존 FR-4 코어와 heavy cu 코어와 비교하였다. 연구결과에 의하면 pitch계열 카본코어가 적용된 PCB의 휨강도가 가장 높고 온도에 따른 변형량이 가장 낮았다. 또한, HDI 신뢰성평가 기준의 TC(Thermal Cycling), LLTS(Liquid-to-Liquid Thermal Shock), Humidity 실험을 통해 카본코어가 적용된 PCB는 신뢰성이 확보되었음을 확인하였다. 카본 파이버에 의한 불균일한 비아홀의 표면형상 여부와 드릴비트 마모 가능성을 분석하였는데 비아홀의 표면은 균일하고, 드릴비트의 표면도 매끄러워 카본 CCL의 우수한 드릴가공성도 확인하였다.

• 한국지역사회생활과학회지
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• 제13권2호
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• pp.1-11
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• 2002

This study was conducted to estimate the amounts of the electromagnetic wave penetrating from a cellular phone in a pocket of dress shirt, as well as to test how different the penetration amounts were under the conditions of wearing. It was also investigated the possibilities that the amounts of the electromagnetic wave penetrating could be decreased by using twofold pocket or electromagnetic wave free fabric. The amounts of the electromagnetic wave penetrating were measured in the following five cases; one-layered pocket with 10 different fabrics as dress shirt, a pocket adding a layer of knitted cotton, two-layered pocket with same fabric as dress shirt, two-layered pocket adding a layer of knitted cotton, and one-layered pocket adding a layer of electromagnetic wave free fabric. Each of these five cases were measured using the front and back sides of a cellular phone facing to the body. The results were as follows; 1) The amounts of the electromagnetic wave penetrating were not significantly different in 10 different fabrics and were all above the caution range (0.02mW/$cm^2$). 2) The amounts of the electromagnetic wave penetrating in cases of the back side of the cellular phone to the body, were more than in cases of the front side. 3) There is a significantly differences in part on adding a knitted under wear to one and two layers of the pocket in the case of penetration amount under the wearing conditions. 4) The amounts of the electromagnetic wave penetrating in cases of adding a layer of electromagnetic wave free fabric, were close to the safe standard value of it. The above results suggested that facing the front side of cellular phone to the body and using extra layering with some electromagnetic wave free fabrics might have some protective effects again to the penetration amounts.

• 한국의류산업학회지
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• 제22권5호
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• pp.650-659
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• 2020

The present study provides reference data required for the design of clothing for the elderly by analyzing the body surface area during fitness motion based on 3D scan data of Korean elderly women. This study was conducted with the procedures of (1) survey of motions and main muscles for fitness, (2) acquisition of 3D scan data, and (3) analysis of rate of change for body surface area during fitness motion. Acquisition of 3D body scan data was obtained from seven elderly females (age: 64-77). We selected 66 anatomical landmarks (40 upper body and 22 lower body) by referring to previous studies. Body surface was segmented by connecting the landmarks marked on the 3D scan data acquired. Analysis of body surface area was conducted in terms of the change rate of surface area in 9 postures of elbow 0°, 90° and 180° for flexion, shoulder 90°, 180° for flexion, shoulder 0°, 180° for abduction, hip 90° for flexion, and knee 90° for flexion compared to the those in the standing posture. The amount of changes in body surface area were 12%-62% in the upper body, 15%-77% in the arm, and 10%-51% in the lower body. A future study on the rate of change of body surface length is needed; in addition, a study on how to apply the results of body surface area and body surface length analysis to clothing pattern design is also necessary.

• 한국의류학회지
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• 제33권8호
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• pp.1227-1240
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• 2009

This study examines the actual conditions of toddler playwear preference survey for design and function. The study develops proper indoor and outdoor playwear for toddlers based on the analysis. A survey of 200 parents with toddlers between 2 and 6 years old and 120 teachers was conducted to find the conditions and needs for playwear along with the necessary design elements. Second, 6 designs including 3 designs for indoor playwear and 3 designs for outdoor playwear were made. These designs emphasized on soil contamination part, color, pattern, form, material, detail, and fasteners. Art play and cooking play are considered for indoor playwear and ways to decrease contamination on sleeve hem, elbow, chest, and knee were determined through the use of yellow, green, and blue colors. Applying a character and separate top with sleeves were determined. Light with breathable and waterproof fabric was determined. The correct amount of Velcro fasteners or buttons was determined for front fastening in addition a pocket was considered necessary as a detail part. The common design for both boys and girls along with a proper design for diverse play were determined. For outdoor playwear, water play, sand play, movement play, and ecology experience are considered and ways to decease contamination on hip, sleeve hem, and knee should be applied to the design as determined through the use of yellow, green, blue, and red colors. The demands for pattern, form, material, and details were similar to indoor playwear. Zipper and buttons for front fastening were determined. These final 6 playwear designs are presented using CAD WALK DESIGNWARE.

• 한국자동차공학회논문집
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• 제18권1호
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• pp.23-30
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• 2010

Trends of the automotive market require the application of new engine technologies, which allows for the use of different types of fuel. Since ethanol is a renewable source of energy and it contributes to lower $CO_2$ emissions, ethanol produced from biomass is expected to increase in use as an alternative fuel. It is recognized that for spark ignition (SI) engines ethanol has advantages of high octane number and high combustion speed. In spite of the advantages of ethanol, fuel supply system might be affected by fuel blends with ethanol like a wear and corrosion of electric fuel pumps. So the on-board hydrogen production out of ethanol reforming can be considered as an alternative plan. This paper investigates the influence of ethanol fuel on SI engine performance, thermal efficiency and emissions. The results obtained from experiments have shown that specific fuel consumption has increased by increasing ethanol amount in the blend whereas decreased by the use of hydrogen-enriched gas. The combustion characteristics with hydrogen-enriched gaseous fuel from ethanol reforming are also examined.