Evaluation of Intermediate Phases Formed on the Bonding Interface of Hot Pressed Cu/Al Clad Materials

이광석,Sangmok Lee,Jong-Sup Lee,Yong-Bae Kim,Geun-An Lee,Sang-Pill Lee,Dong-Su Bae 대한금속·재료학회 2016 METALS AND MATERIALS International Vol.22 No.5

The aim of the present study is to identify the properties of intermediate phases formed on the bonding interface of hot pressed Cu/Al clad materials by transmission electron microscopy and nano-indentation analyses. Cu/Al clad materials were fabricated by hot pressing under 200 MPa at 250 °C for 1 h and then heat treated at 400 °C for 1 h. Nano-indentation measurement was conducted to evaluate the nanohardness and modulus of the intermediate phases formed between the Cu/Al interfaces. A 3-tier diffusion layer was observed at the Cu/Al interfaces. Knoop microhardness values at the bonding interface were 7 to 11 times that of the Cu and Al matrix metals. The intermediate phases formed at the bonding interface were Al4Cu9, AlCu, and Al2Cu. A mapping analysis confirmed that the Al and Cu particles moved via mutual diffusion toward the intermediate phases formed at the bonding interface. The nanohardness values of η2-AlCu and γ1-Al4Cu9 were 4 to 7 times that of the Cu and Al matrix metals. Nanohardness and Knoop microhardness measurement curves exhibited similar tendencies. The rigidity values of the respective intermediate phases can be arranged in descending order as follows: γ1-Al4Cu9 > η2-AlCu > θ-Al2Cu.

경골에 시행한 유리 생 비골 및 피부편 이식

이광석,박종웅,하경환,한상석,Lee, Kwang-Suk,Park, Jong-Woong,Ha, Kyoung-Hwan,Han, Sang-Seok 대한미세수술학회 1997 Archives of reconstructive microsurgery Vol.6 No.1

We have evaluated the clinical results following the 46 cases of free vascularized osteocutaneous fibular flap transfer to the tibial defect combined with skin and soft tissue defect, which were performed from May 1982 to January 1997. Regarding to the operation, flap size, length of the grafted fibula, anastomosed vessels, ischemic time of the flap and total operation time were measured. After the operation, time to union of grafted fibula and the amount of hypertrophy of grafted fibula were periodically measured through the serial X-ray follow-up and also the complications and results of treatment were evaluated. In the 46 consecutive procedures of free vascularized osteocutaneous fibular flap transfer, initial bony union were obtained in the 43 grafted fibulas at average 3.75 months after the operation. There were 2 cases in delayed unions and 1 in nonunion. 44 cutaneous flaps among the 46 cases were survived but 2 cases were necrotized due to deep infection and venous insufficiency. One necrotized flap was treated with latissimus dorsi free flap transfer and the other was treated with soleus muscle rotational flap. Grafted fibulas have been hypertrophied during the follow-up periods. The fracture of grafted fibula(15 cases) was the most common complication and occurred at average 9.7 months after the operation. The fractured fibulas were treated with the cast immobilization or internal fixation with conventional cancellous bone graft. In the cases of tibia and fibula fracture at recipient site, the initial rigid fixation for the fibula fracture at recipient site could prevent the fracture of grafted fibula to the tibia.

Thermo-optic Effects of Optical Temperature Sensor

이광석,김현덕,Lee, Kwang-Seok,Kim, Hyun-Deok The Korea Institute of Information and Commucation 2006 한국정보통신학회논문지 Vol.10 No.11

본 연구는 에칭된 실리카 기반의 평면 도파로 Bragg grating에 기반한 광 온도센서의 열전 광 효과에 대한 선형 및 비선형 해석에 대하여 제시하였다. 또한, 에칭된 평면 도파로 Bragg grating 광 온도센서의 이론적인 해석과 실험을 행하고 그 결과를 나타내었다. 도파로에 기반한 grating응답에 대하여 선형 온도 효과보다 비선형의 이론적 모델과 plate deformation이론이 허용오차 범위 내에서의 실험치와 일치함을 알 수 있었다. This paper demonstrates a comparison of linear and nonlinear analyses for thermo-optic effects of optical temperature sensor based on the etched silica-based planar waveguide Bragg grating. Topics include theoretical analyses and experiment of the etched planar waveguide Bragg grating optical temperature sensor, Theoretical models with nonlinear than linear temperature effect for the grating response based on waveguide and plate deformation theories agree with experiments to within acceptable tolerance.

생유리 피부편을 이용한 종부 및 족저부 연부조직 결손의 재건

이광석,강기훈,권규호,임당재,Lee, Kwang-Suk,Kang, Ki-Hoon,Kwon, Kyu-Ho,Lim, Dang-Jae 대한미세수술학회 1998 Archives of reconstructive microsurgery Vol.7 No.2

We have investigated the clinical results of 33 cases of free flap transfer performed for the soft tissue defects of heel and sole. In donor sites, tensor fascia lata flaps were 4, dorsalis pedis flaps were 10, forearm flaps were 9, and latissimus dorsi flaps were 10. The recipient sites were heel in 22 cases, sole in 7 cases, and heel and sole in 4 cases. In these cases, the postoperative complications, morbidity of donor sites, recovery of sensation, and cosmetic results were evaluated in each flap. All the flaps survived successfully. The free flaps provided excellent functional and cosmetic results. The tensor fascia lata flap was more reliable free flap for the reconstruction of heel and sole defects.

국내 제과점에 대한 소비자 만족도 및 구매행동 및 이용실태에 관한 연구

이광석,이승범,정효선,Lee, Kwang Suck,Lee, Seung Bum,Jung, Hyo Sun 한국식품조리과학회 2015 한국식품조리과학회지 Vol.31 No.2

This study considered the intake patterns and realities of consumptions at bakeries in Korea. Based on a total of 442 customers obtained from empirical research, and self-administrated questionnaires were collected and analyzed by using frequency, chi-square, and one-way ANOVA. Satisfaction with the preferred bakery was shown to be in the order of taste, service, product, and price. A most considered factor in selecting the bakery was taste. The visiting frequency was shown to be the highest for 1~2 times a week. The expense per visit was shown to be won 5,100~10,000 on average. The purchase of refreshment was shown to be the most frequent propose of visiting. The product that was mainly being purchased was the sweet dough bread. It was answered to be difficult because of failing to know to contained materials when purchasing product at bakery. Limitations and future research directions are also discussed in this study.

미세수술을 이용한 발뒤꿈치 재건

이광석,허창룡,김학윤,서정대,Lee, Kwang-Suk,Huh, Chang-Young,Kim, Hak-Yoon,Suh, Jeong-Dae 대한미세수술학회 1994 Archives of reconstructive microsurgery Vol.3 No.1

저자들은 1980년 1월부터 1993년 5월까지 종골부위의 피부결손이나 또는 골결손을 동반한 연부조직 손상이 있었던 총 22례 환자에 대하여 유리피판술 또는 생골및 생피부편 이식술을 시행하고 최저 1년 이상 추시하여 다음과 다음과 같은 결과를 얻었다. 1. 유리 피부편의 크기는 최저 $7cm{\times}6cm$에서 최대 $28cm{\times}10cm$로 평균 $12.1cm{\times}9.2cm$였고, 유리 골편의 크기는 각각 $4cm{\times}3cm$, $5cm{\times}4cm$였다. 2. 재건술에 이용된 방법으로 유리 피부피판술은 족배 비판 11례, 서혜부 피판 2례, 전완부 피판 2례였고, 유리 피부근피판술은 활배근 피부근피판 3례, 대퇴근막장근 피부근피판 2례였으며, 골결손을 동반한 연부조직 손상인 경우 2례에서 생장골 피부편을 이식하였다. 3. 총 22례중 19례에서 유리편이 생존하여 86.4%의 성공율을 보였으며, 수술후 혈전증 2례와 감염이 발생하였던 1례에서 실패하였다. 이상의 결과로 볼 때, 고식적인 방법으로 치료하기 어려운 발뒤꿈치의 연부조직 또는 골결손의 치료로서 미세수술을 이용한 유리편 재건술이 유용한 방법으로 사료되며, 발뒤꿈치의 감각신경 회복에 대하여는 향후 지속적인 연구가 필요한 것으로 사료된다. The heel, with its specialized fat for shock absorption at heel strike and large surface area for balance and weight bearing, is a important component of normal ambulation. Despite of distinguished improvement in the field of microsurgical free flaps, the choice of reconstruction of the heel has been remained controversial. We reviewed 22 cases of the heel reconstruction using vascularized free flaps from January, 1980 through May, 1993 at the Department of Orthopedic Surgery of Korea University Hospital. The results were as follows: 1. The etiology was traumatic in 21 cases, and chronic ulceration due to burn in 1. 2. The arteries used in free flaps were 11 dorsalis pedis arteries, 2 deep circumflex iliac arteries, 2 supeficial iliac arteries, 2 branches of lateral femoral circumflex iliac arteries, 2 radial arteries, and 3 thorcodorsal arteries. 3. The mean size of the vascularized bone was $4.5cm{\times}3.5cm$, and that of skin flap was $12.1cm{\times}9.2cm$. 4. Of the 22 cases, 19 had a successful outcome and 3 in failure, the causes of failure were thrombosis and infection.

사지에 발생한 신경초종의 미세수술적 치료

이광석,우경조,김종원,Lee, Kwang-Suk,Woo, Kyung-Jo,Kim, Jong-Won 대한근골격종양학회 1996 대한골관절종양학회지 Vol.2 No.1

Neurilemmomas are the most common benign tumor of the peripheral nerve trunks, and arises from the cells in the sheath of Schwann. Neurilemmomas are well encapsulated and may be separated easily from surrounding tissue and lie completely within a larger nerve trunk, with bundles of neurofibrils spread out over the surface of the tumor. A careful dissection and retraction of the nerve bundles will allow the tumor to be enucleated from the parent nerve without any significant interference with the function of the nerve. Resection of the involved nerve is seldom necessary and should be avoided if at all possible. Our aim in microscopic excision of neurilemmoma of extremities is to reduce any disturbance of the intact neurofibrils of the parent nerve. Thirteen cases of neurilimmomas were treated by microscopic excision at the Department of Orthopaedic Surgery, Korea University Hospital between January 1990 and March 1995. The results was as follows ; 1. The average age at surgical intervention was 40.1 years. Cases in fourth and fifth decades predominated. 2. In their anatomical distribution, 8 cases were in the upper extremity and 5 cases in the lower extremity. 11 cases were on the flexor surface. 3. On the operative field, all the tumors were well encapsulated, however 1 case of 13 was adherent to the periosteum of fibula. 4. In all cases, the tumor were enucleated from the parent nerve without any injury to nerve under high-power magnification, preserving individual fascicles, and sensory and motor function.

상완 신경총 손상후 견관절의 외전 및 주관절의 굴곡 재건을 위한 신경 이전

이광석,강기훈,한상원,이기홍,Lee, Kwang-Suk,Kang, Ki-Hoon,Han, Sang-Won,Lee, Ki-Hong 대한미세수술학회 1998 Archives of reconstructive microsurgery Vol.7 No.2

We have performed the operations for the restoration of shoulder abduction and elbow flexion in 17 patients(20 cases of neurotization) of brachial plexus injury at the Department of Orthopaedic Surgery, Korea University Hospital from October 1991 to May 1997. The mean follow-up period was 42 months. After neurotization for brachial plexus injury, functional recovery of shoulder abduction and elbow flexion were good and fair in 65%. In the functional evaluation, the clinical results of whole arm type were poorer than those of upper arm type, and the operations performed within 6 months since the injury were better than those of other cases.

천이구간 추출 및 근사합성에 의한 음성신호 압축과 복원

이광석,이병로,Lee, Kwang-Seok,Lee, Byeong-Ro 한국정보통신학회 2009 한국정보통신학회논문지 Vol.13 No.2

In a speech coding system using excitation source of voiced and unvoiced, it would be involved a distortion of speech qualify in case coexist with a voiced and an unvoiced consonants in a frame. So, We proposed TS(Transition Segment) including unvoiced consonant searching and extraction method in order to uncoexistent with a voiced and unvoiced consonants in a frame. This research present a new method of TS approximate-synthesis by using Least Mean Square and frequency band division. As a result, this method obtain a high qualify approximation-synthesis waveforms within TS by using frequency information of 0.547kHz below and 2.813kHz above. The important thing is that the maximum error signal can be made with low distortion approximation-synthesis waveform within TS. This method has the capability of being applied to a new speech coding of Voiced/Silence/TS, speech analysis and speech synthesis. 유 무성음의 음원을 이용한 음성부호화 시스템에서는 프레임 내에 유성자음과 무성자음이 공존하는 경우에 음질왜곡을 일으킬 수 있다. 따라서 프레임 내에 유성자음과 무성자음이 공존하지 않도록 하기 방법으로써 무성자음을 탐색하고 검출을 포함하는 천이 구간을 제안하였다. 본 연구는 최소 자승법과 주파수 대 역 분할법을 사용함으로써 TS 근사합성의 새로운 방식을 제시하였으며 결과적으로 이는 0.547KHz이하와 2.813kHz 이상에서의 주파수 정보를 이용함으로써 TS내에서 고품질의 근사합성 파형을 얻을 수 있었다. 보다 중요한 것은 최대 오류신호는 TS 내에 저 왜곡 근사 합성파형이 생길 수 있다는 것이다. 이 방식은 유성음/묵음/TS의 새로운 음성부호화, 음성해석 및 음성 합성에 적용할 수 있으리라 생각한다.

파이프 크기와 굴곡에 적응하는 탐사로봇 설계 및 구현

이광석,이병로,추연규,Lee, Kwang-Seok,Lee, Byeong-Ro,Choo, Yeon-Gyu 한국정보통신학회 2009 한국정보통신학회논문지 Vol.13 No.3

기존의 대부분의 각종 파이프 탐사로봇은 고정크기로 유선 케이블 통신방식으로 구성되어 사용되고 있다. 파이프 굴곡과 각도(수평, 기울어 짐, 수직)를 가지는 파이프 구조에서는 파이프 탐사작업이 매우 어려운 실정이다. 따라서 본 연구에서는 탐사로봇의 구조를 파이프를 스프링의 장력으로 밖으로 밀어내는 방식으로 제안 설계하였으며 통신방식을 RF 통신방식으로 변경 개선하였다. 이와 같은 구조 및 기능 개선으로 인해 로봇 한대로 허용오차내의 파이프 크기와 굴곡에 적응이 가능함으로써 운용의 효율성이 제고되었으며 파이프 내부의 문제점(균열, 부식, 슬러지 등)을 사전 모니터링하고 DB화하였다. 또한 새로이 제안하고 설계 개발된 탐사로봇은 소형, 경량이므로 운반과 동작이 매우 유리함을 확인할 수 있었다. Most of explorer robot in past has the fixed magnitude and communicate with wire communication method. In case of various range of pipe's width and various angle in pipe inter structure, the exploring work is very difficult. Thus, in this paper, we design as dealing with spring tension with pushing out pipe exterior, and applied RF communication. We can accept good performance both structure change and improvement of ability, monitor and collect the defaults data in pipe inter structure. Newly designed and developed pipe explorer robot is very advantageous to carrying and driving as being small and law weight.