18 Ni 마르에이징 강의 기계적 성질에 미치는 Mo 첨가량의 영향

김학모,김인배,박세윤 ( Hak Mo Kim,In Bae Kim,Se Yoon Park ) 한국열처리공학회 1991 熱處理工學會誌 Vol.4 No.3

Effects of Mo content and aging conditions on the amount of retained austenite and mechanical properties of 18 Ni maraging steels were investigated. Maraging steels were fabricated with variation of Mo content, 3, 5, 7, 9% and heat treated by austenitizing at 840℃ for 1 hour and then aged at 480℃ for 0.5∼100 hours. It was found that the amount of retained austenite after aolution treatment was negligible up to 5% Mo. 8 and 11 volume percents of retained austenite were obtained with 7 and 9% Mo respectively. The maximum hardness and yield strength without great loss of impact toughness were attained in the range of 4∼8 hours of aging time at 480℃ with 5% Mo. It was concluded, as a result, that the optimum Mo content for the good combination of strength and toughness is to be 5% Mo.

대구치에서 회전식 NiTi file의 수명과 파절양상

김진우,안병두,박세희,신혜진,조경모 大韓齒科保存學會 2005 Restorative Dentistry & Endodontics Vol.30 No.3

Intracanal separation of the rotary files is a serious concern in modern endodontic practice. The objective of this study was to compare the life span and fracture patterns of three NiTi rotary files in molar teeth. Mesiobuccal roots of upper molar (n = 150) and mesial roots of lower molar (n = 150) were divided into three groups and each group was prepared with Profile, ProTaper, and K3 respectively. Every file was used until separation and/or deterioration of the cutting blade was happened, and then the number of canals to separation and/or unwinding were recorded. Radiographs and Scanning electon microscope (SEM) photographs were taken to evaluate the patterns of separation. The results were as follows: 1. There were no significant differences in numbers of canals to separation and/or unwinding among the groups. 2. Comparing between flaring files, K3 showed significant lower numbers of canals to separation and/or unwinding (p < 0.05), and there was no significant difference between shaping files 3. Separations of instruments were occurred at the midpoint of curvatures within the canals 4. In SEM observations, ductile fractures were seen in most of cases, characterized by shallow dimples. Additional researches is needed to provide a new guideline that informs the appropriate number of times to use NiTi files. 회전식 NiTi file은쉽게 파절되는 단점이 있으나 이에 대한 연구는 아직 부족하다. 본 연구에서는 회전식 NiTi file을 이용해 실제 치아에서 근관을 형성하고, 이 때 발생하는 파절 및 변형을 연구, 분석하였다. 상악 대구치의 근심협측 치근 (n = 150)과 하악 대구치의 근심치근 (n = 150)을 실험대상으로 하여 Profile, ProTaper 및 K3로 각각 근관형성 하였다. 각 file은 파절되거나 변형이 생길 때까지 계속하여 사용한 다음 그 사용횟수를 기록하였다. 파절의 양상을 관찰하기 위해 방사선 및 주사현미경 사진을 촬영하였다. 1 세 군간의 유의할만한 사용횟수의 차이는 없었다. 2. Flaring file 간의 비교에서는 K3의 사용횟수가 통계적으로 유의성 있게 적었으며 (p < 0.05), shaping file 간에는 유의할만한 차이가 없었다. 3, 회전식 NiTi file의 파절은 근관의 최대 만곡부에서 발생하였다. 4. 주사전자현미경으로 파절면을 관찰한 결과 연성파괴의 전형적인 양상인 얕은 딤플이 관찰되었다. 일반적으로 회전식 NiTi file의 평균 사용횟수는 제조회사의 사용지침보다는 길었으며, NiTi file의 수명에 대한 새로운 사용지침을 만들기 위한 부가적인 연구가 있어야 되리라 사료된다.

熱刺戟 電流法에 依한 MOS酸化層內 移動性 陽이온의 擧動에 關한 考察

金種聲,崔世崑,姜星模 嶺南大學校 工業技術硏究所 1988 연구보고 Vol.16 No.1

TSIC(Thermally stimulated ionic current) method, based on the repeated measurements with various heating rates, has been used to investigate the kinetic behavior of mobile ions in the SiO₂layers of an Al-SiO₂-Si system. Experimental results have shown two current peaks at the temperature ranges of 80℃-120℃(A peak) and 400℃-450℃(B peak) respectively, which are caused by the release of Na+ ions and K+ ions trapped at the Al-SiO₂ interface and the Si-SiO₂ interface respectively, in a MOS structure. From the results, activation energies (E), attempt-to-escape frequencies (S) and the initial number of trapped ions(n。)are evaluated for each group by the various heating rate method. According to the values of E.S and n。, it is found that deeper traps are distributed in the Si-SiO₂ interface and that K+ions are trapped in deeper trap than Na+ ions. It is also found that the magnitude of the current peaks is increased while the tempratures showing those peaks are decreased, as the gate voltage is increased.

21세기의 초등학교 무용교육방향에 관한 연구

김세정,이근모 釜山大學校 師範大學 1998 교사교육연구 Vol.35 No.-

This study is aimed at objectifying several procedures for desiable direction of basic dance instruction. The procedures are first, consideration of 〈Journal of Korean Elementary school Dance Education Society〉 to seek current goal and emphasized point of dance instruction. Second, revealing educational value different from that of established by studying realistic and axiom definition of dance. Third, seeking education requirement necessary for fostering as desirable social component necessary for future by arrangement of opinion of future scholar to measuring desirable direction of 21century. Finally, predicting the desirable direction of 21century by these considerations mentioned previously. The result is that the direction of future dance education to foster desirable human for 21century should not emphasize only the body, creation, activity, etc emphasized as current motion education and inspiration of union consciousness should be include folk dance able to inspire union consciousness.

바닥輻射 煖房시스템의 熱傳達 特性

연인모,김대기,이세균 충북대학교 건설기술연구소 2002 建設技術論文集 Vol.21 No.2

The object of this study is to investigate the thermal characteristics of heating system with floor radiation for residential building. As a first step, the thermal resistance of floor constructed with mortar and concrete has been studied while hot water is supplied through pipe under the floor surface. A heat transfer model of floor heating system which has natural convection and radiation from floor surface to the heating space has been developed to predict the heat transfer and the temperature of floor surface. Also, expriments have been performed and the results have been compared with those of heat transfer model. This study does not include all the heat transfer characteristics associated with typical heating system with radiant floor in detail. However, heat transfer modeling developed in this study can be a first step in design of comfortable floor temperature. Therefore, the results of this study can provide important informations to construct and optimize such a system.

Rieger syndrome : 증례보고 A CASE REPORT

이홍모,김정욱,장기택,이상훈,한세현,김종철 大韓小兒齒科學會 2003 大韓小兒齒科學會誌 Vol.30 No.4

Rieger syndrome은 눈의 전안방 기형과 치아결손을 특징으로 하는 희귀한 유전질환으로 두 개안면 이상과 체성기형을 동반하기도 한다. Rieger syndrome은 상염색체 우선유전(autosomal dominant inheritance)되며, 발생빈도는 약 200,000분의 1이고, Paired-like homeodomain transcription factor2(PITX2)의 변이가 이 질환과 연관이 있는 것으로 보고되고 있다. 본 증례는 Rieger syndrome으로 진단 받은 4세 7개월 된 여아에 대한 것으로, 양안에 다동공증과 후태생환을 보이고, 측모두부계측에서 상악골 열성장이 나타났으며, 상악유측절치와 더불어 다수의 영구치 결손이 방사선 상에서 관찰되었다. 이 증례를 통하여 Rieger syndrome 환아의 구강 및 두 개안면의 소견을 관찰하고, 관련 문헌을 고찰하여 다소의 지견을 얻었기에 보고하는 바이다. Rieger syndrome is a rare, autosomal dominant gentic disorder characterized by malformation of the anterior chamber of the eye(goniodysgenesis) coincident with hypodontia. It may also be accompanied by a spectrum of dental, craniofacial and somatic anomalies. Mutations in paired-like homeodomain transcription factor2(PITX2) are associated with the syndrome, and its frequency in the general population has been estimated to be 1 : 200.000. In the present case, the patient, 4 year 7 month-old female, had posterior embryotoxon and polycoria. The maxilla was retrusive in cephalometric radiography. She had congenital missing on #52, #62 and some tooth germs of permanent tooth were not detected in panoramic radiography. The purpose of this paper is to report the dental and craniofacial findings and review the pertinent literature through this case.

21C를 향한 부산 지역의 Green사회체육 활성화 방안

이근모,오세복,김윤숙,김세정,이영덕 釜山大學校 附設 體育科學硏究所 1996 體育科學硏究所 論文集 Vol.12 No.-

The purpose of this study was to create plan of Green Sport for all in Pusan toward 21st century. The plan of Green Sport for all in Pusan toward 21st century was conducted by theoretical analysis based upon an advanced countries' sport for all state and Pusan's sport for all state. The result of this study are as follows; 1. To set plan for sport for all in Pusan, it should consider the environment of sport for all for citizen's social welfare. It is more important to use the present facilities effectively with the good management than expand sport for all facilities. To set budget for all facilities to expand it is expected from 2002 Pusan Asian Games's profit. 2. The public sport facilities and sport for all facilities should be open for citizen after build sport for all facilities at the near river and sea side. It should give permission to build green sport for all facilities in the zone of protect development. The regulation of entrance fees at the public sport center such as basketball gymnasium, soccer stadium, and baseball stadium. To enter public sport center, it is recommended free for athletes to do competition or exercise and for citizen the lowest fee is recommended during whole year. The officials should be consider very good quality of service for citizen. Also, school's sport facilities are recommended to open for citizen after school off. 3. It is recommended to build one sport center at every district(gu) in Pusan like Sport for all Pusan association (The memorial olympic hall). The olympic park should protect forever, it should not be allowed for other purpose whenever. 4. The government should set budget for labor's sport clubs. Also, the government try to encourage to expand labors' sport facilities in the company as the law promotion for labors' sport. 5. The government and the government of Pusan city should lead every company to keep the law of promotion for labors' sport. Also, the government leads company to promote sport for labors at each company by the reduction of taxation for company such as th incorporation tax and a real estate acquisition tax. For example, the government let them reduce company's tax for company's private sport facilities(center) so give them chance to invest for sport facilities. 6. KOC should keep remain neutral to promote territory's sport, university team in Seoul should get away from the victory oriented idea then they might participate as amateur at the national tournament. 7. To reduce traffic at the center of the Metropolis, the energy saving purpose, the effective using of the center of the Metropolis, and to increase sport for all people, the green sport for all underground facilities are recommended at the foot of Youngdo park and the public elementary, junior, high school's ground without the nature damage. And then it will be help a lot to citizen to stress out and to use effective leisure time for themselves. 8. It was suggested that the green sport for all facilities might build in the sea near the yacht race center at Soo young, Haeundae bathing resort and Kwangan ni bathing resort, with minimizing nature damage. The green cultural resport and ocean sport facilities were recommended at the sea side to play yacht, wind surfing, water ski, and water bicycle for touring and sport for all purpose. 9. The green winter sport resort and sport resort were recommended at Seungji park and Daeshin park for citizen. After build these facilities, it should be open for citizen every day.

FORMOCRESOL을 이용한 치수절단술시 FORMALDEHYDE의 전신적 흡수 및 급성독성에 관한 연구

이범모,한세현,김관식,정동균 대한구강생물학회 1990 International Journal of Oral Biology Vol.14 No.1

Formaldehyde that is active constituent in formocresol used in pulpotomy is known as toxic agent that causes systemic toxicity. To determine the fate of the ^14C-formaldehyde which was absorbed following its application to pulpotomy sites, by-pass of posterior facial vein and cannulation of external carotid artery were established with 20G-polyethylene tube. Blood samples (0.2ml) were collected in glass syringe before the pulpotomy and then at 0, 3, 5, 10, 20, 30, 45, 60, 90 and 120 minutes thereafter. Plasma was separated after centrifugation at 3000 x g for 15 min and aliquots of plasma were counted by liquid scintillation counter. After liver, kidney, lung ,heart, spleen, muscle, and alveolar socket were removed and solubilized with tissue solubilizer, the radioactivities in solutions were counted by liquid scintillation counter. The acute toxicity of formocresol was determined by BUN, GOT and OCT assay in blood samples collected 0, 2, 4, 6, 9 and 12 hours by means of cardiac puncture. The results were as follows ; 1. The radioactivity of ^14C-formaldehyde reached maximal value at 3-5 minutes and decreased thereafter. 2. About 8% of ^14C-formaldehyde placed in the pulpotomy site was actually absorbed systemically until 2 hours. 3. About 50% of ^14C-formaldehyde absorbed actually was distributed within 20 minutes. 4. The radioactivity of organ per gram was highest in the spleen and lowest in the muscle. 5. Total radioactivity of organ was highest in the liver and lowest in the heart. 6. There were no significant differences between control and experimental groups in BUN, GOT and OCT assay.

K3에 축적된 내부 응력이 피로 파절에 미치는 영향

김준영,김진우,조경모,박세희 大韓齒科保存學會 2012 Restorative Dentistry & Endodontics Vol.37 No.2

Objectives: This study aimed to evaluate the relationship between the cyclic fatigue of a K3 file and internal stress intentionally induced until the activation of the auto-stop function of the torque-controlled motor. Materials and Methods: K3 (Sybron Endo) .04 and .06 taper, size 25, 30, 35, 40 and 45 were used in this study. To give the internal stress, the K3 files were put into the .02 taper Endo-Training-Bloc (Dentsply Maillefer until the activation of the auto-stop function of the torque-controlled motor. The rotation speed was 300 rpm and torque value was 1.0 N·cm. K3 were grouped by the number of induced internal stress and randomly distributed to 4 experimental groups (n = 10, Stress 0 [control], Stress 1, Stress 2 and Stress 3). For measuring the cyclic fatigue failure, the K3 files were worked against a sloped glass block and time for file separation was recorded. Data was statistically analyzed Statistical analyses were performed using two-way ANOVA and Duncan post-hoc test at p < 0.05 level. Results: Except .04 taper size 30 in Stress 1 group, there were statistically significant differences in time for file separation between control and all experimental groups. K3 with .04 taper showed higher cyclic fatigue resistance than those of .06 taper. Conclusion: In the limitation of this study, the cyclic fatigue of the K3 file was influenced by the accumulated internal stress from use until the auto-stop function was activated by the torque-controlled motor. Therefore, clinicians should avoid the reuse of the K3 file that has undergone auto-stops. (Restor Dent Endod 2012;37(2):74-78)

Resilon을 이용한 근관충전 시 레진계열의 근관실러와 자가-접착 레진시멘트에 따른 미세누출

함선영,김진우,신혜진,조경모,박세희 大韓齒科保存學會 2008 Restorative Dentistry & Endodontics Vol.33 No.3

The purpose of this study was to compare the apical microleakage in root canal filled with Resilon by methacrylate-based root canal sealer or 2 different self-adhesive resin cements. Seventy single-rooted extracted human teeth were sectioned at the CEJ perpendicular to the long axis of the roots with diamond disk. Canal preparation was performed with crown-down technique using Profile NiTi rotary instruments and GG drill. Each canal was prepared to ISO size 40, .04 taper and 1 ㎜ short from the apex. The prepared roots were randomly divided into 4 experimental groups of 15 roots each and 5 roots each for positive and negative control group. The root canals were filled by lateral condensation as follows. Group 1: Gutta-percha with AH-26, Group 2: Resilon with RealSeal primer & sealer, Group 3: Resilon with Rely-X Unicem, Group 4: Resilon with BisCem. After stored in 37℃, 100% humidity chamber for 7 days, the roots were coated with 2 layers of nail varnish except apical 3 ㎜. The roots were then immersed in 1% methylene blue dye for 7 days. Apical microleakage was measured by a maximum length of linear dye penetration after roots were separated longitudinally. One way ANOVA and Scheffe' s post-hoc test were performed for statistical analysis. Group 1 showed the least apical leakage and there was no statistical significance between Group 2, 3, 4. According to the results, the self adhesive resin cement is possible to use as sealer instead of primer & sealant when root canal filled by Resilon. 본 연구의 목적은 Resilon을 이용한 근관충전시 methacrylate-based root canal sealer와 자가-접착 레진시멘트의 사용에 따른 치근단 미세누출을 비교해 보는 것이다. 70개 단근치를 ProFile NiTi rotary instrument와 GG drill을 이용해 근관성형 하였다. 치근을 4개의 실험군 (n = 15)과 2개의 대조군 (n = 5)으로 분류하여 측방가압법으로 충전하였다. <1군: GP + AH-26, 2군: Resilon + RealSeal primer&sealant, 3군: Resilon + Rely-X Unicem 4군: Resilon + Biscem> 7일간 1% 메틸렌블루 용액에 침적 후 수직절단하여 치근첨부터 색소의 침투도를 측정하였다. 1군에서 가장 적은 미세누출값이 측정되었고, 2, 3, 4군 간의 통계적 유의성은 없었다. 이번 연구의 결과에 따르면, 자가-접착 레진시멘트는 Resilon을 이용한 근관충전시 sealer로 사용이 가능하리라 생각된다.