자발공 행공수련이 스트레스, 불안감, 삶의 만족감에 미친 영향

곽동열,이형환 한국자연치유학회 2013 Journal of Naturopathy Vol.2 No.2

후열처리 온도에 따른 티타늄 코팅의 기계적 특성 평가

곽동열,박태성,이태훈,김용식,박익근 한국비파괴검사학회 2019 한국비파괴검사학회지 Vol.39 No.5

Titanium coating is widely used in various industries due to its high-strength as well as thermal and chemical stability. Post-annealing of titanium coating leads to specific surface characteristics or enhanced mechanical properties. Microstructure characteristics such as grain size, density, morphology, and crystal structure of the coating layer can be changed by post-annealing conditions. These variations affect the structural and functional properties of titanium coating. In this study, titanium coatings measuring 1μm in thickness were deposited on a silicon wafer via direct current (DC) magnetron sputtering and the coatings were conducted via post-annealing at different temperatures ranging from 350°C to 800°C. The fabricated specimens were analyzed using scanning electron microscopy, atomic force microscopy, and X-ray diffraction. The mechanical properties were measured via nano-indentation and scanning acoustic microscopy. The mechanical properties of the titanium coatings fabricated at different post-annealing temperatures were evaluated by analyzing the relationships between microstructure and mechanical properties. 티타늄 코팅은 우수한 강도와 열적, 화학적 안정성으로 인해 다양한 산업분야에 광범위하게 사용되고 있고 특정한 표면 특성을 얻거나 기계적 특성을 향상시키기 위해 후열처리를 수행한다. 이 때 후열처리 조건에 따라 코팅층 내부 입자의 크기, 밀도, 형태, 결정 구조 등과 같은 미세구조적 특성들이 변화되고 티타늄 코팅의 구조적, 기능적인 특성에 많은 영향을 미친다. 본 연구에서는 DC 마그네트론 스퍼터링 기법으로 실리콘 웨이퍼 위에 1 μm 두께의 티타늄 박막을 증착하였고 350℃에서 800℃까지 온도를 다르게 후열처리를 수행하였다. 제작된 시험편을 SEM, AFM, XRD의 미세구조 분석 기법들을 적용하여 분석하였고 나노인덴테이션과 초음파현미경을 이용하여 기계적 물성을 측정하였다. 후열처리 온도에 따른 미세구조의 특성과 기계적인 특성과의 상관 관계를 확인하여 제작된 티타늄 코팅의 기계적 특성을 평가하였다.

원자로 내부구조물 배플포머볼트 검사의 초음파 신호 시뮬레이션

곽동열,이태훈,이정석,오승진,김왕배 한국비파괴검사학회 2022 한국비파괴검사학회지 Vol.42 No.5

Simulation of ultrasonic signals has been widely used to elucidate the propagation behavier of ultrasonic signals in beams and to analyze the signal characteristics of defects in beams. In this study, a simulation was performed using CIVA software, a nondestructive testing simulation tool, to analyze the characteristics of ultrasonic signals generated during the inspection of baffle former bolts in practice. The ultrasonic signals from bolts with no defect, notches in the head-shank, and notches in the thread were compared to their respective simulated signals, and the results indicated a good agreement. In addition, the feasibility of the experimental signals from phased array ultrasonic testing (PAUT) was verified through comparison with the simulated results. PAUT can overcome the limitations of conventional probes during inspection of baffle former bolts and enhance the detectability of defects at various angles. 초음파 신호 시뮬레이션은 초음파 빔의 전파거동 이해와 결함의 신호 특성 분석을 위해 많이 사용된다. 본 연구에서는 실제 배플포머볼트 검사에서 수집된 초음파 신호 특성을 분석하기 위해 비파괴검사 분야의 시뮬레이션 툴인 CIVA 프로그램을 이용하여 시뮬레이션을 수행하였다. 결함이 없는 교정 볼트와 볼트 목 및 나사산 부위에 결함이 있는 각각의 대비 볼트에서 얻어진 초음파 신호를 시뮬레이션 신호와 비교한 결과 매우 유사한 결과를 확인하였다. 또한 종래의 배플포머볼트 검사 탐촉자의 한계를 극복하고 다양한 각도의 결함에 대한 검출능을 높일 수 있는 위상배열초음파를 이용한 실험 데이터와 시뮬레이션 결과를 비교함으로써 위상배열초음파검사의 가능성을 검증하였다.

자발공의 형태개발과 인체의 파동감지능력 연구

곽동열,이형환 한국자연치유학회 2012 Journal of Naturopathy Vol.1 No.1

수지 손상에서 NEUROVASCULAR ISLAND FLAP을 이용한 SENSOY RESTORATION

고성훈,윤성호,김용희,곽동열 大韓成形外科學會 1993 Archives of Plastic Surgery Vol.20 No.2

For successful reconstruction on finger injuries, we must maintain the digital length, preserve nail function, provide adequate soft tissue padding, and most importantaly, give near normal sensation without pain. The critical areas most utilized in picking up and holding objects are the proximal volar aspect of thumb and the proximal radiovolar aspect of index finger. Authors have perfomed neurovascular island flap in 21 patients from March, 1989 to June 1989 and followed up for 2 years. The results were summarized as follows: (1) None of 18 patients had sensory reorientation of island flap. (2) Seventeen of 19 patients had double sensibility in donor and recipient finger and the remained 2 patients had sensibility only to donor finger. (3) Seventeen of 18 patients had sensory recovery of donor finger although hypoesthesia. (4) Ten of 13 patients had neurotization into previously covered groin flap, and of the 10 patients, three patients had neurotization into donor finger. (5) Four of 18 patients had two point discrimination below 15mm.

직류 마그네트론 스퍼터링으로 증착된 은 박막에서의 산소 검출에 관한 연구

곽동열(Dong Ryul Kwak),조승범(Seung Bum Cho),강동찬(Dong Chan Kang),김용성(Yong Sung Kim),박태성(Tae Sung Park),박익근(Ik Keun Park) 한국비파괴검사학회 2018 한국비파괴검사학회지 Vol.38 No.5

박막 증착 공정에서는 기판 온도, 압력, 전압뿐만 아니라 스퍼터링 공정에서 발생된 산소의 검출량과 같은 미소량의 변수가 박막의 특성에 영향을 미칠 수 있다. 본 연구에서는 고진공의 직류 마그네트론 스퍼터링 공정으로 제작된 박막에서 산소의 존재 여부를 확인하기 위해 유리 기판 위에 110 nm의 두께로 은박막을 증착하였다. 스퍼터링 공정에서 DC 출력 제어 및 아르곤 분압 조절 조건과 DC 출력 조절 및 아르곤분압 제어 조건을 다르게 하여 박막을 제작하였고 X선 회절분석법과 레이저 유도 플라즈마 분광분석법을 적용하여 산소의 검출 여부를 확인하였다. 스퍼터링 공정에서 발생된 산소 음이온의 영향으로 은 박막의 표면과 깊이 방향으로 산소가 분포되었고 스퍼터링 조건에 따라 산소의 양이 다르게 검출됨을 확인하였다. The properties of thin films can be effected by small variations such as in the amount of oxygen present during thin film deposition and in sputtering parameters, including the substrate temperature, working pressure, and sputtering voltage. In this study, silver thin films with 110 nm thickness were deposited on a glass substrate by DC magnetron sputtering with high vacuum levels for oxygen detection. The silver thin films were fabricated by keeping the DC output voltage constant and varying the Ar pressure and then varying the DC output voltage and keeping the Ar pressure constant in the sputtering process. Then, X-ray diffraction and laser-induced breakdown spectroscopy analyses were conducted to detect the induced oxygen in the films. The results showed that induced oxygen was present on the surface and along the direction of depth due to the oxygen ions in the sputtering process and that the amount of oxygen differed according to the sputtering parameters.

심신치유를 위한 자발공(自發功) 행법의 기(氣)적 분석

곽동열 ( Dong Yeol Kwak ),이형환 ( Hyung H Lee ) 한국자연치유학회 2013 Journal of Naturopathy Vol.2 No.2

The purpose of this study is to analysis of feeling of the developed motion of spontaneous Qigong naturally appearing in the particular Qigong state for mind and body therapy. For the spontaneous qigong exercise, there have been developed 5 types of Haenggongs (practical motions) for each of 6 levels, 30 Haenggongs in total. The types of developed Spontaneous Qigong were analyzed as the preparatory and arm haenggong, the front body haenggong, the leg haenggong, the abdominal haenggong, the back and head haenggong, the whole body haenggong and sugong levels. This is to harmonize the body and mind by connecting the whole body and moving the qi naturally. As the motions of spontaneous qigong are for the movement of qi, the muscle is contracted at the non-moving part and relaxed relatively at the moving part. The respiration is conducted with the danjeon (abdominal) breathing. The consciousness just follows the movement of arm. In the change of gi-feeling, the power of qi gets stronger when legs go up; the power gets weaker when legs go down. The first level is the preparatory and arm haenggong and its qi-feeling part is mainly the both palms. The second level is the body haenggong and its qi-feeling part is the chest, both rib sides and the lower abdomen. The third level is the leg haenggong and its qi-feeling part is from the left leg and to the lower danjeon. The fourth level is the abdominal haenggong and its qi-feeling part is around the lower danjeon. The fifth level is the back and head haenggong and its qi-feeling part is from the head to the tailbone. The sixth level is the whole body and sugong and its qi-feeling part is the whole body and the lower danjeon. In conclusion, the spontaneous qigong has the characteristic that the movement of haenggong is based on the natural conducts which the start and the end are mutually connected. The qi is moved evenly around the whole body in six levels, maintaining the balance of qi or energy through the repetition of moving and stopping, bending and stretching, contracting and relaxing and ascending and descending. It can be said the spontaneous qigong is the practice to circulate the energy in the body by establishing the specific form of spontaneous generation with the information of body based on the principle of consciousness and unconsciousness are coexisting.

원자로 배플포머볼트 검사를 위한 초음파 신호 시뮬레이션

곽동열(Dong Ryul Kwak),이태훈(Tae Hun Lee),이정석(Jeong Seok Lee),오승진(Seung Jin Oh),김왕배(Wang Bae Kim) 한국비파괴검사학회 2022 한국비파괴검사학회 춘계학술대회 초록집 Vol.2022 No.5

고감쇠 재료에서 위상배열초음파 FMC-TFM 기법의 적용

곽동열(Dong-Ryul Kwak),이태훈(Tae-Hun Lee),김왕배(Wang-Bae Kim) 한국비파괴검사학회 2021 한국비파괴검사학회 춘계학술대회 초록집 Vol.2021 No.6

고감쇠 재료에서 위상배열초음파의 FMC-TFM 기법 적용에 관한 연구

곽동열(Dong Ryul Kwak),이태훈(Tae Hun Lee),김왕배(Wang Bae Kim) 한국비파괴검사학회 2021 한국비파괴검사학회지 Vol.41 No.5

고감쇠 재료에서는 초음파 빔의 왜곡과 감쇠 특성 때문에 하나의 압전소자로 송·수신하는 위상배열초음파의 Full Matrix Capture (FMC) 기법을 적용할 경우 충분한 음압으로 반사 신호를 취득하기 어려울 수 있다. 따라서 고감쇠 재질에 대해서 FMC에 기반한 Total Focusing Method (TFM) 기법의 적용 가능성을 확인할 필요가 있다. 본 연구에서는 2.25 MHz, 32개 소자의 선형 위상배열탐촉자를 사용하였고, 304 스테인리스강 시험편과 주조 오스테나이트 스테인리스강 시험편에 있는 동일한 위치의 측면공에 대하여 일반적인 위상배열초음파검사 신호와 FMC 데이터를 각각 수집하였다. 수집된 FMC 데이터는 후처리 기법을 통해 Sectorial 스캔 및 TFM 이미지로 합성되었고 각 결과의 측면공 수신 신호의 진폭을 비교하였다. 304 스테인리스 강 대비 고감쇠 재료인 주조 오스테나이트 스테인리스 강 시험편에서 FMC 데이터로 합성된 원거리 측면공 신호의 진폭 비율이 일반적인 위상배열초음파검사 결과보다 더 낮게 나타났다. 이를 통해 고감쇠 재료에서 FMC-TFM 기법을 적용하기 위해서는 수신 신호의 진폭 감소율을 고려하여 최종 합성 신호 품질을 확인해야 한다. Obtaining received response signals with sufficient sound pressure can be difficult because of the distortion and attenuation of ultrasonic waves in high-attenuation materials when full matrix capture (FMC) technique is applied for transmitting and receiving the signal by each element in phase arrayed ultrasonic testing (PAUT). Therefore, it is necessary to verify the application of a total focusing method (TFM) based on the FMC for the materials. In this study, a linear phased array probe with 32 elements and a center frequency of 2.25 MHz was used and both commercial phased array response signals and FMC data were collected for side drill holes (SDHs) at the same position in 304 stainless steel and cast austenitic stainless steel. The corrected FMC data were then synthesized to sectorial scans and TFM images via post-processing, and the received response amplitudes for the SDHs were compared. In case of the cast austenitic stainless steel of high attenuation versus 304 stainless steel, the rates of response signal amplitude for the far-distance SDH obtained by using the FMC dataset collection was lower than those obtained by using the commercial sectorial scan of PAUT. Consequently, the quality of the final synthesized signals should be investigated by considering the reduction rate of received response amplitudes for application of the FMC-TFM technique to high-attenuating materials.