Ni-Cr 강과 지르코니아와의 접합에 관한 연구

정형진,유연철,하문영,이용철 대한금속재료학회(대한금속학회) 1989 대한금속·재료학회지 Vol.27 No.9

Studies have been conducted to clarify the joining phenomena of ZrO₂ to Ni-Cr steel produced by solid-state diffusion bonding with Al interlayer. The reaction layer at the steel/Al interface was observed clearly. By the EDX analysis, it was confirmed that this layer was a diffusion layer of Al and Fe. Reaction layer of the Al/ZrO₂ interface could not be detected in spite of good contact suggesting that the Al/ZrO₂ interface was bonded by a surface reaction in which a layer of less than 1㎛ in thickness was formed. It is concluded that the optimum conditions for bonding of ZrO₂ to Ni-Cr steel are of the Al interlayer of 0.6㎜, applied pressure of 100 MPa, temperature of 635℃, and time of 120 minutes. The interface shear strength of 50 MPa is obtained under these conditions.

경비골 도달법을 이용한 족관절 유합술 시 외과의 보존과 희생 방법의 차이에 따른 결과

정형진,배서영,신용운,임동주,조성일,Chung, Hyung-Jin,Bae, Su-Young,Shin, Yong-Woon,Lim, Dong-Ju,Cho, Sung-Il 대한족부족관절학회 2010 대한족부족관절학회지 Vol.14 No.2

Purpose: We analyse and report the result of transfibular ankle arthrodesis using lateral malleolar saving procedureversus lateral malleolar sacrificing procedure. Materials and Methods: Eighteen cases of transfibular ankle arthrodesis which were performed since 2001 were included. We devided them into lateral malleolar saving and lateral malleolar sacrificing groups. We reattached and fixed lateral malleolus in 10 cases and sacrificed malleolus for morcelized bone graft in 8 cases. We evaluated clinical results by AOFAS ankle-hindfoot score, visual analogue scale (VAS) and radiological results by union time. Complications and subjective satisfaction degrees were also recorded and compared between two groups. Results: Preoperative mean AOFAS score was 32 points (16~41) and VAS was 7.5 points (7~8) and they were changed into 68.6 points (61~77) and 2.8 points (2~4) postoperatively. There was no significant difference in clinical results between the two groups even though lateral malleolar saving group showed higher AOFAS score (69.4) than lateral malleolar sacrificing group (67.7). Duration of getting union was 11.3 weeks in lateral malleolar saving group and 10.6 weeks in lateral malleolar sacrificing group. There was no difference in subjective satisfaction level. There were one delayed union and one nonunion in lateral malleolar sacrificing group and one nonunion in lateral malleolar saving group. Conclusion: There was no difference in clinical and radiological results between lateral malleolar saving group and lateral malleolar sacrificing group of transfibular ankle arthrodesis. Therefore it may not necessary to sacrifice lateral malleolus for bone graft except very selective case for which heavy graft is needed.

종골 부정 유합에 대한 두개의 골편을 이용한 거골하 관절 신연 유합술

정형진,배서영,이희성,Chung, Hyung-Jin,Bae, Su-Young,Lee, Hee-Sung 대한족부족관절학회 2009 대한족부족관절학회지 Vol.13 No.1

Purpose: This study was designed to evaluate the results and efficacy of subtalar distraction two bone-block arthrodesis for calcaneal malunion. Materials and Methods: From January 2004 to June 2007, we operated on 8 patients (12 cases). There were 7 male patients and 1 female patient; their mean age was 42 years. 8 cases among them were operated initially. The period between initial injury and arthrodesis was 21 months. At an average follow up was 19 months. In operation, we used extensile lateral approach and arthrodesis was performed through tricortical two bone-block and cannulated screws. The Ankle-Hindfoot scale was used for clinical evaluation. In radiologic analysis, plain X-ray and CT were examined union and various parameters. Results: All cases achieved radiologic union at the final follow-up. The mean Ankle-hindfoot scale (maximum of 94 points) increased from 43.4 points preoperatively to 84 points at the final follow-up. The radiologic analysis of the pre- and postoperative standing lateral radiographs showed and average increase of 5.5 mm in talo-calcaneal height, $5.1^{\circ}$ in talocalcaneal angle, $6.1^{\circ}$ in talar declination angle and decrease of $5.7^{\circ}$ in talo-first metatarsal angle. Conclusion: The short term results of subtalar distraction two bone-block arthrodesis is promising, but longer follow-up was needed.

해부학적 잠김 압박 금속판을 이용한 원위 비골 골절의 치료

정형진,Chung, Hyung-Jin 대한족부족관절학회 2013 대한족부족관절학회지 Vol.17 No.2

Purpose: Preshaped Locking compression plate(LCP) has holes with fixed angle between screw and plate and have advantage firm fixation because it has stability of angular and axial deformity. We evaluated usefulness of LCP after open reduction and internal fixation in distal fibular fracture. Materials and Methods: Between December 2011 and May 2012, 23 patients with fracture of distal fibula were followed up at least 12 months underwent open reduction and internal fixation with LCP. There were 15 males and 8 females with a mean age 39.8(20~69) years. According to Danis-Weber classification, there were 20 cases of type B and 3 cases of type C. There were 13 cases of isolated lateral malleolus fractures, 1 case of bimalleolar fracture, 6 cases of trimalleolar fractures and 3 cases of distal tibia fractures with proximal fibula fracture. Intraoperatively, we assessed whether preshaped LCP fit lateral margin of distal fibula or not and evaluated quality of reduction and postoperative complications. The cases were analyzed by radiological bone union time and clinical results according to the criteria of Meyer Results: Of all cases, complete bone union was achieved and average radiological bone union time was 7.3(6~12) weeks. The clinical results were excellent in 18 cases(78%), good in 5 cases(22%). There were 5 cases of plate with 3 holes, 13 cases of plate with 4 holes, 2 cases of plate with 5 holes, 1 case of plate with 6 holes and 2 cases of plate with 7 holes. The average number of screws at proximal fragement was 2.5 and at distal fragment was 3.5. In 14 cases (60.8 %), we needed re-bending of plate because the distance between plate and lateral cortical margin of distal fibula was more than 5 mm at anteroposterior X-ray after reduction. All cases have anatomical reduction and there were no complications of wound infections. There were no complaint about hardware irritation. Conclusion: At fractures of distal fibula,preshaped LCP had a excellent stability although far cortex was not fixed with screw and bending of plate. And there are less complications of hardware irritation and wound problems. But, Some complement would be needed because there were no complete fitting between precontour of LCP and lateral cortical margin of distal fibula.

광범위 외측 도달법을 이용한 관절내 종골 골절의 수술적 치료

정형진,안종국,배서영,정훈,Chung, Hyung-Jin,Ahn, Jong-Kuk,Bae, Su-Young,Jung, Hoon 대한족부족관절학회 2009 대한족부족관절학회지 Vol.13 No.1

Purpose: This study was designed to investigate the usefulness of extensile lateral approach for accurate reduction and rigid internal fixation in comminuted intraarticular fractures of calcaneus. Materials and Methods: From October 2002 to May 2007, we managed 55 patients (62 cases) with open reduction and internal fixation using extensile lateral approach. Among these, 38 patients (43 cases) who underwent preoperative and postoperative CT scan were enrolled. All patients were evaluated over 24 months after surgery. Bohler angle and Gissane angle on plain X-ray, displacement and step-off of articular surface of calcaneus on CT scan were measured and we compared the difference between preoperative and postoperative value of them. Clinical results were assessed by using AOFAS Ankle-Hindfoot Scale. Results: The average Bohler angle was restored from $6.8^{\circ}$ to $23.5^{\circ}$ and Gissane angle was improved from $116.4^{\circ}$ to $113.5^{\circ}$ after operation. The average distance of displacement was restored from 4.2 mm to 1.4 mm and step-off of articular surface was recovered from 5.1 mm to 1.3 mm. Clinical results were excellent in 17 cases, good in 18 cases, fair in 3 cases, and poor in 5 cases. 10 cases developed postoperative complications such as skin necrosis, heel pain, limitation of motion of ankle and subtalar arthritis. Conclusion: The extensile lateral approach is valuable for the comminuted intraarticular fractures of calcaneus that enables accurate anatomical reduction and rigid internal fixation by providing direct exposure of subtalar joint.

정저항요업체의 제조와 전기적 성질

정형진,윤상옥 한국세라믹학회 1985 한국세라믹학회지 Vol.22 No.2

The semiconducting ceramics having positive temperature coefficient of resistivity in he family of 0.25mol% $Sb_2O_3$ doped barium titanates were prepared with AST ($4Al_2O_3$.$9SiO_2$.$3TiO_2$) and $MnO_2$ as additives and these electrical properties were investigated. The PTCR characteristic in these ceramic materials was improved by the addition of AST and $MnO_2$ because the addition of AST decreased the room temperature resistivity and controlled grin size due to the formation of a liquid phase during sintering and the addition of $MnO_2$ improved by forming acceptor level on the intergranular layer. On dependence on the switching time as switching temperature was increased the initial power and switching time increased.

이트리아를 함유한 지르코니아 고체전해질의 물리적, 전기적 특성

정형진,오영제 한국세라믹학회 1986 한국세라믹학회지 Vol.23 No.1

Zirconia soild electrolytes containing 4~10mol% of yttria were prepared by wet-blending of oxides and rea-ction-sintering, Sinterbility and degree of stabilization were optimized for the development of oxygen sensor. Fracture strength thermal expansion coefficient electrical conductivity and galvanic potential were measured and discussed with respect to the amount of ytria addition phase transformation microstructure and degree of stabilization. It was found that sintering and stabilization occurred when the composition was designed to be near the boundary region of $ZrO_2-Y_2O_3$ binary system. In such away a good zirconia solid electrolyte suitable for oxygen sensor could be developed.

空軍士官生徒의 血液像

鄭亨鎭 공군본부 의무감실 1958 항공의학 Vol.6 No.1

종골의 부정 유합

정형진,Chung, Hyung-Jin 대한족부족관절학회 2012 대한족부족관절학회지 Vol.16 No.2

Calcaneal fractures account for 2% of all fractures and approximately 60 to 70% of tarsal fractures. These fractures typically are the result of high-energy injury, such as a motor vehicle accident or a fall from a height. The potential for disabling malunion following intrarticular displaced calcaneal fracture is high, regardless of treatment. Fracture displacement typically results in loss of hindfoot height, varus and widening of the hindfoot, with possible subfibular impingement and irritation of the peroneal tendon and/or sural nerve. Frequently, subtalar joint develops posttraumatic arthritis. In symptomatic patients with calcaneal malunion, systemic evaluation is required to determine the source of pain. Nonsurgical treatment, such as activity and shoe modification, bracing, orthoses, and injection, is effective in many patients. Surgical treatment may involve simple ostectomy, subtalar arthrodesis with or without distraction, or corrective calcaneal osteotomy. A high rate of successful arthrodesis and of patient satisfaction has been reported with surgical manamgent.

영미법상의 구두증거배제원칙

정형진 한국경영법률학회 2006 經營法律 Vol.17 No.1