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Frankel appliance(FR-2)를 이용한 2급 부정교합 환자의 치험례
이긍호,최영철,부성언 大韓小兒齒科學會 1990 大韓小兒齒科學會誌 Vol.17 No.2
The functional regular(FR-2) is a removable orthodontic appliance developed by Rolf Frankel that is used during the mixed and early permanent dentition stages to effect changes in anteroposterior, transverse, and vertical jaw relationship in class Ⅱ malocclusions. This appliance serves as a template against which the craniofacial muscles function. The framework of the appliance provides an artificial balancing of the environment, thereby promoting more normal patterns of muscle activity. The Frankel also influences skeletal and dental development. The appliance removes muscle forces in the labial and buccal areas that restrict skeletal growth, thereby providing an environment that maximizes mandibular growth. The case presented here and the progressive analysis reveals the forward and downward growth of the mandible remarkably. This patient with severe overjet, convex profile, underdeveloped and retrognathic mandible have been treated with FR-2, and forward and downward growth of the mandible was observed.
레이저 인터페로메타를 이용한 드릴링 머신의 틸팅에 관한 연구
이승수,손영지,장성규,전언찬 동아대학교 공과대학부설 생산기술연구소 1996 生産技術硏究所硏究論文集 Vol.1 No.2
This paper describes tilt angle measurement method. This method measures tilt angle of drilling machine using laser interferometer with simple sliding linear bearing. Measurement method is next orders. First, measurement position is considered pointed contact of two probes. And revolution of drill axis deliver pointed contact of probe. Second, so laser interferometer attach on sliding linear bearing, moving of probe influence laser reflector. And laser program displays this vibration of laser reflector. Namely, this vibration is tilt factor. A lot of error factor have an effect on accuracy to measurement of linear, angular, and so on. But this paper ignores some error factor, because these error festor is very smaller than tilt angle factor which we had been measuring values.
이긍호,부성언 大韓小兒齒科學會 1992 大韓小兒齒科學會誌 Vol.19 No.1
The purpose of this study was to assess the thickness of unpolymerized layers on sealants and to estimate the degree of polymerization of sealants. In this study, amterials used were four kinds of visible light-cured sealants and two kinds of chemically cured sealants. The thickness of unpolymerized layer was assessed by light microscope and the degree of polymerization was analysed by FTIR spectroscopy and following results were obtained. 1. The thickness of unpolymerized layers ranged from 6.33 to 13.89㎛ in light cured sealants and from 67.11 to 75.00㎛ in chemically cured sealants, and the thickness of unpolymerized layer of light cured sealants were thinner than those of chemically cured sealants(p<0.001). 2. As the exposure time incureased, the differences of thickness of unpolymerized layers in light cured sealants were statistically insignificant except differences between 10 seconds group and 20 seconds group of Concise(p<0.01). 3. As the exposure time increased, the increases of degree of polymerization between 10 seconds group and 20 seconds group of Pit & Fissure Sealant and Teethmate-A were statistically significant (p<0.01). 4. The detree of polymerization of Teethmate-A, Fissureseal and Hi-Pol was greater than that of other visible light cured sealants(p<0.01).
BTA드릴에 의한 심공가공시 최적절삭조건과 공구수명에 관한 연구
장성규,이충일,전언찬,안찬우,김현수 동아대학교 공과대학부설 생산기술연구소 1996 生産技術硏究所硏究論文集 Vol.1 No.2
The BTA deep hole machining has an increasing because of its wide range applications and its good productivity. The BTA tools are capable fo machining for having a large length to diameter ratio in single pass. It's really necessary that the research for machining of the deep hole drilling by the BTA drilling because its required quality should be satisfied with one time machining. In machining deep holes by single edge BTA drill, P10 class of tool material out of single tube BTA drilling system, we got the result of our study of selecting the optimum cutting condition and tool life for an object, SM55C through our testing as follows. (1) Cutting speed V=42m/min, and feed speed F=90mm/min is the optimum cutting condition and the tool life was about 10 meters. (2) The testing was shown surface roughness was 12㎛, and the roundness was less 16㎛.
장성규,변상기,이승수,김현수,전언찬 동아대학교 공과대학부설 생산기술연구소 1997 生産技術硏究所硏究論文集 Vol.2 No.1
Among the cutting process, recently hole processing in one of extensive using. This study, we made use of the 3 point edge drill. Regarding the cutting efficiency, we investigated the shape of cutting hole and studied cutting hole, a slope of center shaft, roundness and surface roughness. By using carbide 3 point cutting edge, compare with 2 cutting edge, it is possible that high precision drill processing and near the hole, at extremely limited area, quantity of magnification is a little big. After 15m cutting distance, a gradient of center shaft values was fixed 22㎛. It is necessary that a sufficient consideration concerned with jig intensity of workpiece, cutting conditions etc.
변상기,장성규,이충엽,전언찬 동아대학교 공과대학부설 생산기술연구소 1997 生産技術硏究所硏究論文集 Vol.2 No.2
Cuttingability of carbide step drill is highly progressing the step drill with more then twice diameter rate is so difficult in regrinding and very easy to damage during machining. As the machining of step drill for blind hole is occur to breakage at small diameter position, so it is very difficult to machining. In this experiments, we investigate roundness and surface roughness by machining distance and were identified that the first distance, 5∼10m, was fine with 7㎛ but the around of 15m was happened so much alternation. And we were identified that after 20m was happend stable machining. The surface roughness was happened the same conditions. So application of step drill, we think that the selection of cutting conditions need lots consideration and the study of step drill's diameter ratio is carried out.
Knowledge Acquisition in the Global Strategic Alliance Network
Eon-Seong Lee 한국항해항만학회 2014 한국항해항만학회지 Vol.38 No.3
This paper aims to empirically examine how shipping companies can effectively acquire knowledge from their strategic alliance partners. This paper adopts cooperative network embeddedness mechanism, such as network density and tie closeness, as a channel through which to acquire more knowledge for shipping participants within a strategic alliance network. This study also examines the moderating role of competition between alliance partners in reinforcing the effectiveness of the cooperative relationships on the knowledge acquisition. Based on the literature, hypotheses to predict the aforementioned associations between cooperative network embeddedness and knowledge acquisition and the moderating role of competition in facilitating that association are established. A quantitative research method using survey data conducted in the Korean shipping industry was employed in order to empirically test the presented hypotheses. The results show that if players in a shipping alliance network are embedded in a dense network and have close relationships with their alliance partners, this helps to facilitate a greater degree of knowledge acquisition from the partners; and the impact of network density on the knowledge acquisition would be intensified with the higher level of competition between shipping companies.