ITI 임플란트에서 상부구조의 설계에 따른 삼차원 유한요소법적 응력 분석

박정용,조혜원 원광대학교 치의학연구소 1999 圓光齒醫學 Vol.9 No.2

Nowadays the osseointegrated dental implant has earned a good reputation for its biocompatibility, safety, and usefulness in the field of prosthodontics. But its successful execution does not only depend upon biocompatibility and biofunctionality of the implant, but upon a thorough biomechanical consideration of the superstructure which makes it possible to maintain the implant for a long time. As the living standard of people gets higher, their interest has begun to shift from the recovery of masticatory function to the aesthetic matter. For this reason, diverse kinds of implant fixture and abutment are being used. But when we use them clinically, we need not only good materials and designs but also a thorough analysis of overall occlusal force and stress distribution. For this purpose, we adopted a solid abutment, a cone system, and the 15^* angled abutment for the ITI solid screw implant fixture which is simple in structure and easy to handle. We selected A12O3(CerAdaptTM) for the abutment material with the same form and preprocessed it as a ceramic abutment to restore the implant. We used the high and low positions of the fastening screw and the metal-ceramic and all-ceramic crowns, forming 10 models. The load (100 N) was imposed horizontally, vertically, and obliquely upon the superstructure, and by employing the three-dimensional finite element analysis we compared and analyzed the stress distribution in the crown, abutment, screw, implant fixture, and bone. The results were as follows (1) In three loading conditions, a tendency of highest stress distribution was observed when the horizontal load was given on the labial surface of the crown. (2) In the implant restoration, high stress concentrations were observed in the neck portion of the fixture, in the lingual portion of the abutment cone, and in the middle portion of the screw. (3) In the bone, high stress concentrations were observed in the cortical bone of lingual alveolar crest and in the cortical bone of labial alveolar crest, while low stress concentrations were observed in the cancellous bone under labial alveolar crest and in the apex of the fixture. (4) When the metal ceramic crown was used, high stress concentrations occurred in the solid abutment, but when the all ceramic crown was used, high stress concentrations occurred in the 15 degree angled abutment. (5) In the cone system abutment, the A1203 abutment tended to show higher stress concentrations than the solid abutment. (6) In the solid and cone system titanium abutments, using the metal ceramic crown showed higher stress concentration than using the all-ceramic crown. But in the other abutments, using any sort of crown material made no significant difference. (7) In the position of the screw head, its low position tended to show higher stress distribution.

고우 / 고우 김영구 목사를 영결함

박정용 기독교대한성결교회 활천사 1958 활천 Vol.298 No.-

인쇄전자 산업시장의 현황과 전망

박정용,박재수,Park, Jung-Yong,Park, Jae-Sue 한국정보통신학회 2013 한국정보통신학회논문지 Vol.17 No.2

인쇄전자는 다양한 기판에 기능적 소자를 프린팅한다. 인쇄방법은 스크린 인쇄, 플렉소그라피, 오프셋 리소그라피와 잉크젯 방식을 통해 적정한 패턴을 만든다. 인쇄기법을 응용하여 활용하기 때문에 전통적인 극소전자공학에 비하여 생산과정이 간단하고 비용 또한 저렴하다. 잉크젯 및 R2R(Roll to Roll)기술이 발전을 거듭해 왔기 때문에 디스플레이에서 태양전지의 제조까지 그 기술이 활용된다. IDTech(2010)에 의하면, 전자인쇄시장은 2010년에 10.99(억달러)에서 2020년 55.10(억달러)로 커질 것이며, 2030년에는 반도체산업의 규모보다 큰 3,000억 달러가 될 것으로 전망하고 있다. 센서, 배터리, 광전지, 메모리, 스마트카드 시장이 확대되는 등 조명에서 디스플레이까지 인쇄전자산업시장은 성장할 것이다. Printed electronics creates electrically functional devices by printing on variety of substrates. Printing typically uses common printing equipment or other low-cost equipment suitable for defining patterns on material, such as screen printing, flexography, gravure, offset lithography and inkjet. Compared to conventional manufacturing of microelectronics, printed electronics is characterized by simpler and more cost-effective fabrication of high and low volume products. Now there is huge effort towards printing many other more functional components, from displays to transistors to photovoltaic cells, using the full range of printing technologies - from inkjet to roll to roll analogue print techniques. The market for printed electronics will rise from $1.99 billion in 2010 to $55.10 billion in 2020. In 2030, this industry could be $300 billion - larger than the silicon semiconductor industry - from lighting to displays[8].

창업기업의 국제화

박정용,박재수 한국전통시장학회 2023 전통재래시장연구 Vol.10 No.1

조직역량 기반 기업에 비해 제한된 자원을 활용하는 기업가적 기업의 국제화를 분석한다. 국제화 수준 과 속도에 관한 것으로써 기업가, 자원, 활동 간의 조정에 관한 문제이다. 이를 기준으로 기술개발속도가 빠르고 제품수명주기가 짧은 ICT산업 중 센서 반도체 기업 한 곳인 ㈜A를 사례 조사하였다. 형태적으로 모회사의 지원을 받으면서 성장하는 스핀오프 모델에 속한다. 국제화모형은 매그나칩반도체(유)의 근무경 력과 지역의 반도체클러스터, 그리고 센서기술개발능력이 국제화 수준과 속도를 좌우하고 있다. 단순화 시키면 국제화 경험은 기본적으로 중요하고 관련 산업생태계의 클러스터링의 확보, 경쟁시장으로 자체의 기술개발능력의 확산이 중요하다고 하겠다. This paper analyzes the internationalization of entrepreneurial enterprises that utilize limited resources compared to those with excellent organizational capabilities. It is about the level and speed of internationalization, a matter of coordination among entrepreneurs, resources and activities. Based on this, A case study was conducted on Hatchtech Co., Ltd., one of the semiconductor companies in the ICT industry with fast technology development and short product life cycle.. A Co. Ltd. belongs to a spin-off model that grows while receiving support from its parent company. In other words, in the internationalization model of A Corporation, the conditions derived from the business division of MagnaChip Semiconductor(limited company), cooperation between regional semiconductor clusters, and the ability to develop sensor technology determine the level and speed of internationalization. If it is simplified, the experience of internationalization is fundamentally important, and while securing clustering of the related industrial ecosystem, it is transferring its own technology development capability to the competitive market.

남대문전통시장 학생창업프로그램 고찰

박정용 한국전통시장학회 2020 전통재래시장연구 Vol.7 No.-

학생중심의 산학협력은 기업에 종속되지 않으면서 학사일정에 다소 독립적인 성격이 요구된다. 기술개발 등은 다분히 객관적인 목표를 두고 접근하기 때문에 서로 간의 명확한 계약관계가 필요하지만 학생 중심 의 산학협력 모형을 고민한다면 학생의 독립을 도울 수 있는 방향이 의미 있다. 학생의 학습과정 또는 특 정 프로젝트가 자기 일로서 명확해 질 때 취업이나 창업이 가능하기 때문에 이러한 형태로 산학협력의 방향을 잡는 것이 필요하다. 한남대학교 첼린저스 스타트업 프로그램이 이와 같은데 서울 남대문시장에서 학생들의 비즈니스 활동을 경험하고 새로운 독립정신을 갖추는데 방향성을 제시하고 있다. 하지만 전통시장 을 학생역량의 성장 필드로 활용함으로써 학생들의 학습결과와 또 다른 창의적인 결과 둘 다를 충족시키는지 의문이 있다. Student-centered academic-industrial cooperation requires a rather independent nature of the academic calendar without being dependent on the company. Since technology development is very aimed and approached, a clear contract between business and school is required. However, if you consider the student-centered model of industry-university cooperation, there is a way to help students' independence. When a student's learning process or a specific project becomes clear as his or her job, it is possible to find a job or start a business. Hannam University's Challengers Startup Program is like this, showing the direction of students' business activities and new independence at Namdaemun Market in Seoul. However, it is questionable whether the traditional market is used as a growth field for student competency to meet both student learning outcomes and other creative outcomes.

주요 신경과의 연결이 없이 발생한 긴손바닥근의 신경초종

박정용,정성노,손원일,권호 대한성형외과학회 2011 Archives of Plastic Surgery Vol.38 No.4

Purpose: Neurilemoma is benign tumor of the nerve sheath which arises from Schwann cells. It is usually formed along the path of a peripheral nerve but is rarely separate from normal nerve fascicles. We experienced a patient with an isolated neurilemoma localized in the palmaris longus tendon with no connection to the major nerve trunk, which was in an unusual location and has never been reported. We report our case with the review of the literature. Methods: A 23-year-old female visited our clinic with mild pain on the mass at the flexor area of the right wrist which had been present for about one year. The physical examination revealed a 1 × 1 cm sized subcutaneous mass at the flexor area of the right wrist. Sonography and computed tomography showed an ovoid, superficial solid mass on the palmaris longus tendon. Upon surgical excision, a 1 × 0.5 cm sized mass attached to the palmaris longus tendon was found. The tumor had no connection with the median nerve and was detached easily from the palmaris longus tendon. Results: Histological examination demonstrated the mass to be a neurilemoma, which consists of spindle shaped cells with oval elongated nuclei arranged fascicles. No sensory dysfunction or evidence of recurrence was found during the 12 months of postoperative follow-up. Conclusion: We experienced a rare case of neurilemoma attached to the palmaris longus tendon with no connection to the major nerve trunk. We wish to emphasize its unusual location through our case and hope to expand our spectrum in exploring the upper extremity mass.

황기의 볶음 조건에 따른 성분 및 자외선 광보호 활성 변화

박정용,이지연,김형돈,장귀영,서경혜 한국영양학회 2019 Journal of Nutrition and Health Vol.52 No.5

Purpose: Astragalus membranaceus (AM) is an important traditional medicinal herb. Pharmacological research has indicated that AM has various physiological activities such as antioxidant, anti-inflammatory, immunoregulatory, anticancer, hypolipidemic, antihyperglycemic, and hepatoprotective activities. The bioactive substances responsible for the physiological activities in AM, including many antioxidant substances, change during the roasting process. This study investigated and compared the changes in the antioxidant constituents of AM caused by roasting. Methods: DPPH (1,1-diphenyl-2-picryl hydrazyl) and ABTS+ (2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt) radical scavenging activities and their total phenolic content (TPC) were measured. High-performance liquid chromatography (HPLC) analysis was performed to confirm any changes in the isoflavonoids of roasted AM (R-AM),. The cell viability of UVB-induced HDF (Human dermal fibroblast) cells treated with AM and R-AM extracts was investigated. The comet assay was used to examine the inhibitory effects of R-AM extracts on DNA damage caused by oxidative stress. Results: The DPPH and ABTS+ radical scavenging activities were 564.6±20.9 and 108.2±3.1 (IC50 value) respectively, from the 2R-AM. The total phenol content was 47.80±1.40 mg GAE/g from the 1R-AM. The values of calycosin and formononetin, which are the known isoflavonoid constituents of AM, were 778.58±2.72 and 726.80±3.45 μg/g respectively, from the 2R-AM. Treatment of the HDF cells with R-AM (50~200 μg/mL) did not affect the cell viability. Furthermore, the R-AM extracts effectively protected against UVB-induced DNA damage. Conclusion: The findings of this study indicate that R-AM increases its isoflavonoid constituents and protects against UVB-induced DNA damage in HDF cells.

사용자 인증에 대한 보안성을 높인 폰더리스 자동차 스마트 폰 키 시스템 개발

박정용,조경환,김영일 한국자동차공학회 2017 한국자동차공학회 부문종합 학술대회 Vol.2017 No.5

Zr 신합금 핵연료피복관 제조단계의 미세조직, 집합조직 및 부식특성

朴政容,鄭龍煥,鄭然浩 대한금속재료학회 2002 대한금속·재료학회지 Vol.40 No.12

Microstructure characterization, texture measurement and evaluation of corrosion properties were performed at various manufacturing steps from TREX to final tube for advanced Zr fuel cladding tubes. From the result of corrosion test in steam at 400℃, it was found that the corrosion behavior at the early stage was highly affected by crystallographic texture and the corrosion resistance increased when (0002) texture normal to the corrosion surface was well developed. However, the effect of texture on the corrosion behavior decreased when oxide thickness increased. It is suggested that the texture of Zr alloy plays an important role in corrosion behavior at the early stage though the corrosion behavior is dominated by oxide characteristics when thick oxide was formed.

지르코늄 핵연료피복관의 부식에 미치는 내부압력의 영향

박정용,김선기,정용환,정연호 대한금속재료학회 2004 대한금속·재료학회지 Vol.42 No.1

Effect of the internal pressure on the corrosion behavior was investigated for the Zr nuclear fuel cladding tubes which were pressurized up to 2500 psi using Ar gas and corroded in steam of 1500 psi at 400℃. It was found that corrosion resistance of Zr fuel cladding tube was decreased with increasing the internal pressure although corrosion behavior at the early stage was similar irrespective of internal pressure. X-ray diffraction result on the oxide showed that crystal structure was not affected by the applied pressure of 2500 psi. SEM observation on the oxide surface revealed that a number of cracks elongated in axial direction were propagated from surface to interior in the case of 2500 psi. The degradation of corrosion resistance with internal pressure was attributable to the extensive cracking at the oxide surface, which is thought to be originated from the difference of ductility between Zr alloy and oxide when Zr fuel cladding tube was deformed due to the applied internal pressure. However, the increase of corrosion rate with internal pressure was shown to be relatively small. It was therefore suggested that the crack induced at the surface did not propagate to oxide layer in the vicinity of oxide/metal interface which is known to be protective to oxygen diffusion and to control the corrosion behavior.