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.

Matrix Factorization을 이용한 음성 특징 파라미터 추출 및 인식

이광석,허강인,Lee Kwang-Seok,Hur Kang-In 한국정보통신학회 2006 한국정보통신학회논문지 Vol.10 No.7

본 연구에서는 행렬 분해 (Matrix Factorization)를 이용하여 음성 스펙트럼의 부분적 특정을 나타낼 수 있는 새로운 음성 파라마터를 제안한다. 제안된 파라미터는 행렬내의 모든 원소가 음수가 아니라는 조건에서 행렬분해 과정을 거치게 되고 고차원의 데이터가 효과적으로 축소되어 나타남을 알 수 있다. 차원 축소된 데이터는 입력 데이터의 부분적인 특성을 표현한다. 음성 특징 추출 과정에서 일반적으로 사용되는 멜 필터뱅크 (Mel-Filter Bank)의 출력 을 Non-Negative 행렬 분해(NMF:Non-Negative Matrix Factorization) 알고리즘의 입 력으로 사용하고, 알고리즘을 통해 차원 축소된 데이터를 음성인식기의 입력으로 사용하여 멜 주파수 캡스트럼 계수 (MFCC: Mel Frequency Cepstral Coefficient)의 인식결과와 비교해 보았다. 인식결과를 통하여 일반적으로 음성인식기의 성능평가를 위해 사용되는 MFCC에 비하여 제안된 특정 파라미터가 인식 성능이 뛰어남을 알 수 있었다. In this paper, we propose new speech feature parameter using the Matrix Factorization for appearance part-based features of speech spectrum. The proposed parameter represents effective dimensional reduced data from multi-dimensional feature data through matrix factorization procedure under all of the matrix elements are the non-negative constraint. Reduced feature data presents p art-based features of input data. We verify about usefulness of NMF(Non-Negative Matrix Factorization) algorithm for speech feature extraction applying feature parameter that is got using NMF in Mel-scaled filter bank output. According to recognition experiment results, we confirm that proposed feature parameter is superior to MFCC(Mel-Frequency Cepstral Coefficient) in recognition performance that is used generally.

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.

HR(Human Resource) 마케팅을 시작하라

이광석,Lee, Gwang-Seok 벤처기업협회 2007 벤처다이제스트 Vol.102 No.-

상완 신경총 손상의 수술적 치료

이광석,채인정,우경조,구장성,Lee, Kwang-Suk,Chae, In-Jeong,Woo, Kyung-Jo,Koo, Ja-Seong 대한미세수술학회 1995 Archives of reconstructive microsurgery Vol.4 No.1

The authors have reviewed 19 patients of brachial plexus injury who treated by operative methods at Department of Orthopedic Surgery, Korea University Hospital during the period from January 1989 to February 1994. All of these patients were followed up more than one year and following results were obtained. 1. The whole arm type injury was most common(7 of 19 patient) and supraclavicular lesion(15 of 19 patient) was more dominant than infraclavicular lesion(4 of 19 patients). 2. The neurorrhaphy, nurolysis, nerve grafting, and neurotization were performed for the primary neural surgery and secondary reconstructive procedure consist of musculotendinous transfer and free muscle transfer with neurotization. 3. The followed up period was from one year to four years and six months, average being two years and five months. 4. We have obtained satisfactory results in 12 patients among 19 patients.

수부기능의 재건을 위한 기능성 유리 박근 근피판 이식

이광석,한승범,황인철,서동원,Lee, Kwang Seok,Han, Seung Beom,Hwang, In Cheol,Suh, Dong Won 대한미세수술학회 2000 Archives of reconstructive microsurgery Vol.9 No.2

Purpose : We performed this study in order to analyze the clinical results of functioning gracilis musculocutaneous free flap transplantation for reconstructon of hand function in cases of Volkmann's ischemic contracture and massive soft tissue injury of forearm. Materials and methods : 18 cases were reviewed with 5 yeas of mean follow up period. We evaluated total active motion of the finger joints and wrist, pinch and grip strength. Results : The flap were survived in 17 cases and 1 case was failed due to infection. The sum of active motion of finger joints(TAM) was improved from 0 to $173.8^{\circ}$. The average grip and pinch strength was improved from 0 kg to $2.7{\pm}2.1kg$ and from 0 kg to $2.4{\pm}1.6kg$. Conclusion : The results in most cases were acceptable in relatively long term follow-up. It may be an option for reconstruction of hand function in cases of Volkmann's ischemic contracture and traumatic upper extremity injury.

백서에서 Aspirin과 Prostaglandin E₁이 미세혈관 문합의 개존에 미치는 효과

이광석,서정대,한승범,이승준,최인철,김인선,조성진,Lee, Kwang Suk,Suh, Jeong Dae,Han, Seung Beom,Lee, Seung Joon,Choi, In Chul,Kim, In Sun,Cho, Seong Jin 대한미세수술학회 2000 Archives of reconstructive microsurgery Vol.9 No.2

In the field of microsurgery, the vascular obstruction of the microvascular anastomosis by thrombus is one of the most important complication. The purpose of this study is to compare the effect between aspirin and prostaglandin $E_1$($PGE_1$) which act as the peripheral vasodilatation and platelet disaggregation. We have used total 48 white male rats and divided them into three gruoups(A, B and C group). Each group consists of 16 rats respectively. A group is as control, B group is medicated with aspirin(3.0mg/kg/day) and C group with $PGE_1(1.2{\mu}g/kg/day)$. The gross and histopathologic findings at anastomosed site were observed on 3, 5, 10 and 15 days after vascular anastomosis and the results were obtained as the followings. 1. The microvascular patency rate is 81.2% in control group, 93.8% in aspirin group and 100% in $PGE_1$ group. 2. On the histologic examination, the formation of mural thrombus is decreased both in the aspirin and $PGE_1$ group as comparing with the control group and also the hypertrophy of the intima forming from media is less formed in $PGE_1$ group than aspirin group and the degree of thickeness is also less. 3. The fibrosis of media is less observed in $PGE_1$ group than aspirin group. According to the above results, the application of $PGE_1$ to the microsurgery is considered to be effective on the prevention of the thrombus formation and on providing high patency rate.

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.

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.

감염 창상 치료에 있어 유리 피부 및 생골 피부편 이식

이광석,김상범,이대희,전우주,백종률,Lee, Kwang-Suk,Kim, Sang-Bum,Lee, Dae-Hee,Jeon, Woo-Joo,Baek, Jong-Ryoon 대한미세수술학회 2004 Archives of reconstructive microsurgery Vol.13 No.2

Purpose : We analyse retrospectively the clinical result of consecutive free flap and osteocutaneous flap transfer in the chronic osteomyelitis, nonunion combined with infection and soft tissue defect with infection. Materials and Methods : From December 1989 to Jun 2003, free flap and osteocutaneous flap transfer was performed in 225 patients with osteomyelitis or infected non-union. 44 cases of these patients had revealed antibitotics resistant organism in wound culture, and these 44 cases were investigated in the mechanism of the injury, recurrence of infection, radiographic union, follow-up clincal results, and postoperative complications. Results : Among the 44 cases, consecutive procedures of osteocutaneous flap transfers(26 cases) and free flaps(18 cases) were performed. Causative organisms were MRSA(20 cases), Pseudomonas aeruginosa(18 cases), acinetobacter(2 cases), and so forth. Initial bony union was obtained in the average 6.3 months. Recurrence of infection in free flap and osteocutaneous free flap were occurred in 3 and 4 cases respectively. Eventually, all the cases attained successful subsidence of the inflammation. Conclusion : Free flap and osteocutaneousflap transfer have provided the greatest improvement of surgical results in infected non-union, chronic osteomyelitis and soft tissue defect with infection. Further clincal studies maybe required to minimize failure rate.