레이저 초음파를 이용한 표면파 측정 시스템 개발 및 박막의 탄성계수 평가 응용

김윤영(Yun Young Kim),이정명(Jeongmyung Lee),조창훈(Changhoon Jo) 대한기계학회 2022 大韓機械學會論文集A Vol.46 No.3

본 연구에서는 레이저로 여기된 표면파의 전파거동을 이용하여 박막의 탄성계수를 평가하는 측정시스템을 구축하였다. 나노초 펄스 레이저 광을 박막의 표면에 집속시킴으로써 국소적으로 가열된 지점에서 표면파를 생성하였으며, 레이저 간섭계를 사용하여 표면변위를 측정함으로써 시간영역 파형 신호를 얻었다. 실험 결과로부터 탄성계수를 도출하기 위하여 전달행렬법을 이용해 분산곡선을 계산하고 곡선맞춤 하였다. 1.0 μm 두께의 티타늄 박막에 대하여 나노압입시험과 비교검증을 한 결과 6.3% 오차범위 내에서 탄성계수 값이 일치하는 것을 확인하였다. 또한, 박막의 두께가 240 nm로 줄어들었을 때에 탄성계수는 단지 2.7% 증가하여 크기효과는 미미함을 확인하였다. A measurement system was established to evaluate Young’s modulus of thin films using the propagation behavior of the laser-induced surface acoustic wave (SAW). A nanosecond-laser beam was focused onto the surface of the thin film to generate SAW at the locally heated spot, and its time-domain waveforms were obtained using a laser interferometer by measuring the surface displacement. The transfer matrix method was used to calculate the dispersion curve such that Young"s modulus of the film can be deduced from the experimental data by curve-fitting. A 1.0 μm-thick titanium (Ti) film was tested, and the results were in good agreement with that of the nanoindentation testing with an error percentage of 6.3%. In addition, 240 nm Ti was tested, and only a 2.7% increase in the elastic property was observed, showing that the scale effect is not significant.

J-R 곡선에 대한 시편크기의 영향에 관한 연구

조연제,석창성,김영진,양원호,최용식 成均館大學校 科學技術硏究所 1995 論文集 Vol.46 No.1

The objective of this paper is to investigate the constraint effect on fracture resistance curves. A series of fracture toughness tests with different specimen sizes taken from nuclear piping materials(SA312 TP347 SA516 Gr. 70) were performed. Test results show that fracture toughness is increased with increase in specimen size, probably due to the relaxation crack tip constraint. Elastic-plastic finite element analyses were also performed to investigate the constraint effect. Numerical results show that the stress triaxiality at the crack tip is the governing factor for fracture toughness.

금 합금 보철물의 교합면 삭제로 인한 임플란트-골 계면으로의 열전달에 관한 연구

조재영,강선녀,정창모,윤미정,허중보,전영찬 대한치과보철학회 2012 대한치과보철학회지 Vol.50 No.1

연구 목적: 임플란트-골 계면에서 발생하는 과도한 열은 골유착을 저해하여 임플란트의 실패를 유발한다. 이에 이번 연구에서는 임플란트 금 합금 보철물의 교합면 삭제시 임플란트-골 계면으로의 열전달 양상과 냉각 방식의 효율성을 알아 보고자 하였다. 연구 재료 및 방법: 온도 감지 장치 제작을 위하여 Internal cone 연결형태의 임플란트에 16개의K형 열전대를 부착하여 아크릴릭 레진에 포매하였다. 치과용 금 합금과 주조용 abutment를 사용하여 교합면에 3개의 요철을 가지는 시편을 10개 제작하였고, 연결 나사를 이용하여 임플란트와 연결한 뒤 온도 감지 장치를 37℃로 유지되는 수조에 위치시켰다. 저속 핸드피스와 green stone bur를 이용하여 30초 동안 보철물의 요철을 삭제하였는데, 무냉각군, 공기 냉각 군, 물 분사 냉각 군으로 나누어 요철을 삭제하였다. 보철물이 삭제 되는 동안 임플란트의 부위별로 온도가 0.05초 간격으로 기록되었고, 삭제를 멈춘 뒤에도 무 냉각 군의 경우 임계 온도인 47℃ 이하로 온도가 하강할 때까지, 공기 냉각군과 물 분사 냉각군의 경우 삭제 중단 후 30초 동안 추가로 온도를 기록하였다. 냉각 방식에 따른 임플란트-골 계면의 온도를 알아보고, 임플란트의 부위별 온도변화의 유의차를 알아보기 위하여 one-way ANOVA를 실시하였고, Turkey HSD 이용하여 95% 유의수준에서 사후 검증하였다. 결과: 무 냉각 군은 임플란트-골 계면의 온도가 47℃ 이상으로 상승하였으며, 임플란트의 경부에서 유의하게 높은 열이 측정되었다(P>.05). 공기냉각군과 물분사 냉각군은 임플란트-골 계면의 온도가 47℃ 이하로 유지되었다. 무 냉각 군에서 임플란트 경부의 온도가 47℃에 도달되는 데는 약 10.8 ± 1.5초가 소요되었다. 공기 냉각 군과 물 분사 냉각 군 사이에서는 임플란트-골 계면 온도의 유의차가 없었다(P>.05) 결론: 이상의 결과로부터 임플란트 금 합금 보철물의 교합면 삭제 시, 임플란트 주위 조직에 위해를 가할 수 있는 임계 온도 이상의 열이 발생했음을 알 수 있었으며, 냉각방식은 공기 냉각과 물 분사 냉각 모두 효과적이라고 생각된다. PURPOSE. The purpose of this study was to analyze temperature change along the implant-bone interface induced by grinding the occlusal surface of implant gold prosthesis and to compare the temperature generated by grinding of prosthesis with different cooling methods. MATERIALS AND METHODS. The experimental gold prostheses were fabricated with dental gold alloy and castable abutment. The prostheses had 3 cylindrical protrusions on the occlusal surface with 1mm in height. Temperature was measured using 16 thermocouple wires attached to the implant fixture surface and the fixture was embedded in an acrylic resin block inside the 37℃ water bath. Cylinders were grinded for a period of 30 second with a low-speed handpiece with green stone point. One cylindrical protrusion was grinded without cooling, the second one was grinded with air blow, and the third one was grinded with water-spray. RESULTS. The mean maximum temperature was measured more than 47℃ of the implant and the maximum temperature was measured at the cervical portion of the implant in the group without cooling. There was statistically significant difference between the group without cooling and the groups with cooling (P<.05). However, there was no significant difference at all portion of implant in the groups with cooling (P>.05). CONCLUSION. The results of this study support that the grinding of implant gold prosthesis without cooling may damage the peri-implant tissue. The continuous use of air blow and water-spray adjacent to prosthesis during the grinding of implant gold prosthesis may prove to be beneficial for cooling of the implant.

식단배식시 간호사의 개선내용이 잔식량 감소에 미치는 효과 : 일 대학병원을 중심으로

조남수,민순,정영주,장숙희,김연희,주예란 朝鮮大學校 附設 醫學硏究所 2005 The Medical Journal of Chosun University Vol.30 No.1

The purpose of this study was to provide basic materials for the supply of the high quality of meals which meets the need of patients of university hospital in G city, affording the increase their quality and to make proper preparations through the analysis of the cause of leftover food for the improvement of hospital service and for the efficiency of hospital management. For this study, questionnaires from the total 302 patients hospitalized (1st 149, 2nd 100 and 3rd 53 investigated persons) during May 28 to October 28, 2001 were used and the measurement of leftover food was performed in each hospital ward for 1 week. A tool of research was consisted of the total 22 structured questionnaires to improve satisfaction of patient meal and to reduce leftover food, For the distribution of meals, the contents of improved education are 1) The improved ways for the satisfaction of rice and soup were searched 2) Several kinds of Kimchi were diversified 3) Kindness education was repeatedly performed to all distributors for 20 minutes every Thursday afternoon ;1) The preparation of clean meals was educated and supervised 5) Since there was much leftover food, when patients enter hospitalization and leave the hospital, and they change meals, and they miss changed meals, both official document and oral cooperation were requested to each hospital ward person in charge. The research results are as follows: 1. In food quality and service, the negative opinion was shown in the item of food temperature, food amount, cleanness of dinner table, kindness of food distributor. And the positive opinions of Eat much. Eat by half. in the item of food intake amount supplied by the hospital were shown. It was investigated that the leftover food was due to the great amount of food. 2. In the determination of leftover food among several hospital wards, 63 hospital ward (medical treatment hospital) gave the largest leftover food in the first and the second investigation. In the third investigation, 73 hospital ward with long-term patients among hospital wards with the largest leftover food gave the order of soup-kimchi-rice, kimchi-soup-rice as leftover foods. Summarizing these results, it is considered that the reduction of leftover food by the improvement education in hospital meals distribution might help the nutrition intake as well as service improvement in hospital manger and social benefit.

지속적인 점이액의 투여로 치유된 외이도 폐쇄성 각화증 1례

조영기,이윤우,이봉희,이강대 釜算慶南耳鼻咽喉科學會 1996 임상이비인후과 Vol.7 No.2

유산소 운동 능력의 차이가 점증최대운동부하 후 피로회복과정에 미치는 영향

송영주,권대근,성동진,황정윤,박천조,김춘우 한국스포츠리서치 2003 한국 스포츠 리서치 Vol.20 No.1

This study was conducted to investigate the effects of aerobic capacity on blood lactate changes after supramaximal progressive loaded exercise. The subjects were divided into Handball players(HB, n=6)group and Control(CT, n=6)group. All subjects exercised according to the protocol by bicycle erogometer. Blood lactate concentration was also measured during the test time. The RER values of CT group were relatively higher than that of HB group. In particular, the RER values of HR group at exercise 8 & 12min were significantly lower than that of CT group(P<0.05). The blood lactate concentration of HB group was significantly lower than that of CT group at 12min during the exercise(P<0.05). During the recovery times the blood lactate concentration of HB group were significantly lower than that of CT group. In addition, blood lactate clearance of HB group was also higher than that of CT group during the recovery time. From these results, it was suggested that lactate clearance during the supramaximal exercise may be affected by the level of endurance exercise performance.

국제 스포츠 정보 시스템의 동향 분석

육조영,임정일,윤찬호,이무연,노덕선,배진희,이승훈 한국스포츠리서치 2004 한국 스포츠 리서치 Vol.15 No.6

As Follow suggested : The purpose of this study was to consider tendency of modern sports information. today Modernst information system had four areas such as collection, clearance, communication and application So, most literuture of America and Europe was collected, cleared, communicated and apilcated in international sports data base. If we utillited communication circuit properly, we could use sports information beneficently at the laboratory and office. In the future and now, one was that special sports institution needed to obtain Education about sports imformation such as information of specialization, and information of knowledge on both soft phase and hard phase of new media. Although korea used date base of foriegn country efficiently, korea had to make effort to create its own information system and wish to avoid friction of economy and fiction of information.

코칭 관리의 과정 모델 분석

육조영,김희수,윤찬호 한국스포츠리서치 2004 한국 스포츠 리서치 Vol.15 No.5

The purpose of this study is to examine the process of 'coaching(administration)' .For that purpose, this study brought in the concept of the management process (VanderZwaag, H.J.) and the administrative process(Hodgkinson, C.) and examined the process model of 'coaching(administration)' . As the result of this study, the process of coaching (administration)' was characterized as follows. 1. The process model of 'coaching(administration)' consists of philosophy, planning, organizing, managing and valuating. 2. At the stage of philosophy and planning, the policy of 'coaching(administration)' is made. 3. At the stage of organizing and managing, the policy of 'coaching(administration)' is implemented and the process of 'coaching(administration)' goes on toward the purpose effectively. 4. The last stage of process (valuating) feeds back to the stage of philosophy. 5. The stage of philosophy has the possibility for changing the direction of process through the consideration of value.

고등학교 축구경기에서의 운동상해의 구분별 조사 연구

조영석,윤영조 敎育硏究院 東國大學校 1998 교육문제연구 Vol.13 No.-

With the research about frequency and conditions of physical injury of soccer players in high schools, I collected 138 students players of 5 high schools in Seoul, Inchon and Kyunggido areas as samples for the purpose of reaching the goals to stable and proper student training and games and surveyed three areas about physical injury on the soccer playing. the following are the results. 1) General physical injury on the game ① The number of injury in one game : 2.93 The middle of the first and second half ② In proportion to the order of rainy, sunny and cloudy weather, injury occurrence happens. ③ Physical and mental condition before injury is surveyed to be uneasy and unstable ④ The collision between each player is the major reason for the injury 2) Body part of the physical injury on the game ① The most frequently damaged part is the lower extremity ② Edema in the head injury, Hypodermal bleeding in the face injury ③ The contusion in the neck and thoracic injury, the pain in the abdominal injury, the sprain in the lumber injury. ④ The fracture and contusion in the upper extremity and fracture. Sprain and contusion in the lower extremity 3) Tecnic and skill area of physical injury on the game ① When players tackle, the case happens with the highest frequency and the next is when charging. ② Especially when throwing, the lumber region is severely injured. ③ When tackling, the lower extremity injured with 76% and When heading the facial region, with 40% Checking all the results shows that it is very important to prevent every type of physical injuries for soccer players and it is needed to give full attentions to precautionary aspects of them for improving playing aptitudes of players

고속가공을 위한 검사시편에 관한 연구

정종윤,황영수,이춘만,정원지,고태조 한국공작기계학회 2003 한국생산제조학회지 Vol.12 No.4

The properties of a machine tool greatly affect machining quality since a machine tool has large variance in its features. Machine tool makers want to find best machining condition with the one that they have built. Machine builders need to develop test specimen since it helps finding characteristics of machine tools when the machining properties of the specimen are analyzed. This paper develops test specimen to identify features of the main spindle, the feeding device, and the frame of a machine tool. The specimen is machined with a high speed machine and the features of the machine are analyzed with test items. They are surface roughness, overshoot in axial movement, errors in circular movement, feeding with small movement, and compensational error. This work can improve usability for a machine tool in machining practice.