세그먼트화 폴리우레탄을 이용한 고분자 마이크로 액츄에이터의 제작 및 고분자 전극의 상태에 따른 구동성능

정영대(Young Dae Jung),박한수(Han Soo Park),조남주(Nam Ju Jo),정해도(Hae Do Jeong) Korean Society for Precision Engineering 2005 한국정밀공학회지 Vol.22 No.2

This paper is focused on the development of the flexible electrode for disc-type polymer actuators using Segmented Polyurethane(SPU). This paper consists of two parts. The one is about the mechanical property such as elastic modulus. these parameters mainly affect behaviors of polymer actuators and the other is about the electro-chemical property such as the surface resistance of the composite electrode affects the strength of electrostatic force, results in the deformation of polymer actuators. The Young's modulus was measured by UTM. As result, by increasing the modulus of a body of polymer actuators, the maximum displacement of polymer actuators are decreased. The surface resistance of the electrode was measured by 4 point probe system. Compared with the conductive silver grease, the displacement of polymer actuators using carbon black(CB) composite electrodes is comparably small but CB composite electrode should be the practical approach for the improvement of the performance of all-solid actuators, compared with another types of electrode materials.

가정 운동 프로그램이 만성요통환자에 미치는 영향

정영대,이현옥,송민영,Jung, Young-Dae,Lee, Hyun-Ok,Song, Min-Young 대한물리치료과학회 2009 대한물리치료과학회지 Vol.16 No.3

Background: To study the effect of the home exercise program on pain, flexibility, endurance of extensor in chronic back pain patients, and suggest optimal method for home exercise program. Methods: I divided into two groups who has chronic back pain; one is control group who was given a treatment at the hospital only and the other is experimental group who did another exercise after treatment at the hospital, and there were 10 people in each group. The manual therapy were given to all the patients in each group after applying a stupe and an electric treatment, but the experimental group conducted another exercise program at homes. All the exercise programs were applied to patients 12 times for 4 weeks totally. Result: SPSS for win version 12 was used for statistic analysis and independent t-test was used to find changes between two groups. VAS scale was used to show changes in pain between each group. The grade of pain was decreased between pre&post test to -5.60 in control group and -4.80 in experimental group but there wasn't significant difference between each group. Finger tip-to-floor test was used for the flexibility changes and it was increased between pre&post test in both groups but the change of flexibility between each groups didn't show statistical difference. Biering-Sorensen test was used to measure the endurance of extensor and it was increased between pre&post test in both groups but there wasn't significant difference between each group. Conclusion: As you read the results above, for a chronic low back pain patient, application of the manual therapy showed that it has effect on decrease of low back pain, increase of flexibility and endurance of extensor. However, the effect of home exercise treatment was not sure about improvements for chronic low back pain patient. So I think there should need further study about the effect of home exercise treatment except the treatments at hospital and the thorough education for the exercise of lumbar should be done before the study for the accurate experiment.

광조형법을 이용한 고분자 리소그래피에 관한 연구

정영대(Young Dae Jung),이현섭(Hyun Seop Lee),손재혁(Jae Hyuk Son),조인호(In Ho Cho),정해도(Hae Do Jeong) Korean Society for Precision Engineering 2005 한국정밀공학회지 Vol.22 No.1

Mask manufacturing is a high COC and COO process in developing of semiconductor devices because of mask production tool with high resolution. Direct writing has been thought to be the one of the patterning method to cope with development or small-lot production of the device. This study consists two categories. One is the additional process of the direct and maskless patterning generation using SLA for easy and convenient application and the other is a removal process using wet-etching process. In this study, cured status of epoxy pattern is most important parameter because of the beer-lambert law according to the diffusion of UV light. In order to improve the contact force between patterns and substrate, prime process was performed and to remove the semi-cured resin which makes a bad effects to the pattern, spin cleaning process using TPM was also performed. At a removal process, contact force between photo-curable resin as an etching mask and Si wafer is important parameter.

가정 운동 프로그램이 만성요통환자의 요추측만과 골반정렬에 미치는 영향

정영대 ( Young Dae Jung ),이현옥 ( Hyun Ok Lee ),송민영 ( Min Young Song ) 대한물리의학회 2009 대한물리의학회지 Vol.4 No.3

Purpose:To investigate the effect of the home exercise program on pain, scoliosis, pelvic alignment of low back in chronic back pain patients, and suggest optimal method for home exercise program. Methods:I divided into two groups who has chronic back pain; one is control group who was given a treatment at the hospital only and the other is experimental group who did another exercise after treatment at the hospital, and there were 10 people in each group. The manual therapy were given to all the patients in each group after applying a stupe and an electric treatment, but the experimental group conducted another exercise program at homes. All the exercise programs were applied to patients 12 times for 4 weeks totally. Results:SPSS for win version 12 was used for statistic analysis and independent t-test was used to find changes between two groups. VAS scale was used to show changes in pain between each group. The grade of pain was decreased between pre&post test to -5.60 in control group and -4.80 in experimental group but there wasn`t significant difference between each group. Cobb`s degree was used to compare the changes of scoliosis in lumbar and it was improved in each group but there wasn`t significant difference between each group. The measurement of pelvic misalignment was decreased between pre&post test to -1.00 in control group and -2.00 in experimental group but it wasn`t enough to show significant difference between each group. Conclusion:As you read the results above, for a chronic low back pain patient, application of the manual therapy showed that it has effect on decrease of low back pain, improvement of scoliosis in lumbar and pelvic misalignment. However, the effect of home exercise treatment was not sure about improvements for chronic low back pain patient. So I think there should need further study about the effect of home exercise treatment except the treatments at hospital and the thorough education for the exercise of lumbar should be done before the study for the accurate experiment.

자동차용 충격흡수기의 데이터베이스 시스템 구축에 관한 연구

정영대(Young-Dae Jung),박재우(Jae-Woo Park),이석희(Seok-Hee Lee),김영호(Young-Ho Kim) 한국정밀공학회 1997 한국정밀공학회 학술발표대회 논문집 Vol.1997 No.11월-1

생체적합형 고분자를 이용한 박막형 이동기의 제작 및 특성평가

정영대(Young Dae Jung),정해도(Hae Do Jeong) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5

Electro-active polymer (EAP), one of the smart materials, is a new alternative offering ultra-precise movements and bio-compatibility. We present the results of the design, fabrication, and performance evaluation of a fabricated diaphragm-type polymer actuator using segmented polyurethane(SPU). This paper illustrates the relationship between the elastic modulus and maximum deflection as a key property of the Maxwell stress effect and also presents the relationship between the dielectric constant and maximum deflection as a key property of the electrostriction effect, especially in polymer actuators using SPU. A diaphragm-type actuator was used to induce an equation of the vertically distributed load by using a fully clamped circular plate as the boundary condition. To verify the equation, the results were compared to the data measured from load cell. In the near future, a low-cost check valves and bio-robot can be applied by its actuators.

조선업 설계 작업자의 직무 스트레스와 육체적 불편도에 관한 연구

정영대(Young-Dae Jung),윤훈용(Hoon-Yong Yoon) 대한인간공학회 2018 大韓人間工學會誌 Vol.37 No.3

Objective: The purpose of this study is to investigate the job stress factors of shipbuilding design workers. Background: Due to the nature of building a ship in a shipyard being a job-order production, we assume shipbuilding design worker"s duty be in connection with ship production across the board. Therefore, in this study, we investigate the job stress and occurrence of muscular skeletal disorders due to VDT work and provide prevention programs to fit the job characteristics of design workers. Method: Two hundred and fifteen shipbuilding design workers participated in this study, using survey based on "Job stress factors evaluation tool for Koreans" that was developed by KOSHA in 2003. The eight job stress factors, which are physical environment, job requirement, job autonomy, job insecurity, organizational system, unfair compensation, relationship conflict, and workplace culture were analyzed with job characteristics and health characteristics. Results: The results showed that the stress level of a job requirement, was relatively higher than that of manufacturing industry workers, meaning that shipbuilding design workers" duties involve heavier workload, higher time pressures, and bigger responsibilities that of manufacturing industry workers. And the stress level of the four job stress factors which are physical environment, job requirement, job autonomy, organizational system was relatively higher than that of office worker. Conclusion: An analysis of a high reliability could not be carried out due to the small number of responses received compared to the total number of shipbuilding design workers. However, it is possible to find and remove the factors that influence job stress of workers based on the researched contents, and it is also expected that the study will help in establishing prevent programs for musculoskeletal disorders that match the nature of the VDT workers. Application: Through this study, our results are expected to be helpful in reducing the shipbuilding design worker"s job stress and provide better guidelines for VDT syndrome prevention programs.

급속조형법을 위한 실시간 형상 모델링과 VRML 응용에 관한 연구

정영대(Young-Dae Jung),최홍태(Hong-Tai Choi),이석희(Seok-Hee Lee) 한국정밀공학회 1997 한국정밀공학회 학술발표대회 논문집 Vol.1997 No.5월

자동차용 충격흡수기의 데이터베이스 시스템 구축에 관한 연구

정영대(Young-Dae Jung),박재우(Jae-Woo Park),이석희(Seok-Hee Lee),김영호(Young-Ho Kim) 한국정밀공학회 1997 한국정밀공학회 학술발표대회 논문집 Vol.1997 No.11월-2

레버 증폭 구조의 플렉서를 이용한 공초점 현미경의 개발

이상원,김위한,정영대,박민규,김지현,이상인,이호,Lee, Sang-Won,Kim, Wi-Han,Jung, Young-Dae,Park, Min-Kyu,Kim, Jee-Hyun,Lee, Sang-In,Lee, Ho 한국광학회 2011 한국광학회지 Vol.22 No.1

본 연구에서는 레버 증폭 구조를 이용한 플렉서 기반의 나노 스테이지를 설계, 제작하였다. 제작된 나노 스테이지를 샘플 스테이지로 채용한 공초점현미경을 개발하였다. 2차원 이미징의 구현을 위해서, 기존의 공초점현미경은 레이저를 이미징 평면상에 스캐닝하는 방식으로 구현된다. 본 연구에서는 백 나노미터의 구동정밀도를 가지는 나노 스테이지 위에 놓인 샘플을 2차원으로 스캐닝하면서 2차원 이미지를 구현할 수 있는 공초점현미경을 개발하였다. 플렉서 기반의 나노 스테이지는 이중 판스프링, 변위증폭 레버, PZT 엑추에이터 그리고 변위 센서로 구성 되어 있다. 스테이지의 구동 성능 해석을 위해 상용 유한요소 해석 프로그램을 이용하였다. 현미경에 사용되는 광원은 적색광 레이저이며, 레이저는 여러 광학요소를 거쳐 샘플스테이지의 샘플에 입사되고, 반사된 빛은 광센서인 PMT(Photo Multiplying Tube)로 계측되게 된다. 계측된 빛의 크기를 이용하여서 2차원 이미징을 구현하였다. 개발된 공초점 현미경으로 생쥐 귀의 피부조직을 관찰하여 현미경의 이미징 성능을 검증하였다. 설계된 샘플 스테이지는 기존의 공초점 현미경의 기계적인 Beam 스캐너를 대신함으로써 현미경의 광경로 및 전체시스템을 간소화 하였다. A confocal microscope was developed utilizing a scanning sample stage based on a home-built double-compound flexure guide. A scanning sample stage with nano-scale resolution consisted of a double leaf spring based flexure, a displacement amplifying lever, a Piezo-electric Transducer(PZT) actuator and capacitance sensors. The performance of the two-axis stage was analyzed using a commercial finite element method program prior to the implementation. A single line laser was employed as the light source along with the Photo Multiplier Tube(PMT) that served as the detector. The performance of the developed confocal microscope was evaluated with a mouse ear skin imaging test. The designed scanning stage enabled us to build the confocal microscope without the two optical scanning mirror modules that are essential in the conventional laser scanning confocal microscope. The elimination of the scanning mirror modules makes the optical design of the confocal microscope simpler and more compact than the conventional system.