• 대한치과의사협회지
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• 제54권8호
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• pp.592-603
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• 2016

Pathologic tooth migration (PTM) caused by periodontal disease is a relatively common disease with a prevalance rate of 30~55%. It is one of the reasons for periodontal treatment of patients. PTM occurs when various factors related to the position of the tooth are altered and clinical features of PTM include facial flaring, diastema, proximal tilting, rotation, and extrusion of teeth. The purpose of this study was to assess the treatment of teeth of hopeless prognosis through the practice of modified intentional replantation on pathologic migrated tooth. This study presents cases using modified intentional replantation for the treatment of pathologic tooth migration caused by severe periodontitis. Modified intentional replantation is a technique that prepares extraction socket by using an implant drill. Based on 3 cases performed with modified intentional replantation, an improvement of clinical periodontal indicators such as probing pocket depth, bleeding on probing, tooth mobility, and pathologic teeth migration was observed after surgery. Also, the patients were satisfied with the functional and esthetic improvement.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1997년도 추계학술대회 논문집
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• pp.177-182
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• 1997

The purpose of this study is to analyze how tools, guide bush type and the change of cutting speed have effects on the diameter of cutting hole, surface roughness of workpiece and roundness during the deep hole machining of SM55C with solid BTA drill by using BTA drilling system through experiment. Conclusion reached is as follows. (1) The diameter was expanded for 25${\mu}{\textrm}{m}$ at the first section and then was reduced 0${\mu}{\textrm}{m}$ and 15${\mu}{\textrm}{m}$ respectively at the 10m and 20m section comparing to the diameter of tool with respect to the variation of cutting length. (2) It was proved that roughness was below 12S for the whole section of cutting length. (3) The roundness has been below 12${\mu}{\textrm}{m}$. Regarding the polygon phenomenon, it has bee proved that not only uneven number of angle but also even number (quadrilateral, elliptical) of angle were made. (4) Variation of diameter, surface roughness of workpiece and roundness turned out to ve the best at 70m/min of cutting speed, 0.15mm/rev of feed.

• Design & Manufacturing
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• 제6권2호
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• pp.70-73
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• 2012

Drill process is usually used to manufacture a industry about processing, Therefore, the burr problem is very significant, The burrs took place when drill process. And then, sometimes, the burrs are often caused of some problems during automatic such as no good quality products and having good surface roughness products. And also, this paper had some experiments using magnesium. Specially, the magnesium is one of the non-ferromagnetic materials. Magnesium has attracted a lot of interest for using the industry. They offer a possible alternative to steel and aluminum in automotive and aero industries to satisfy the lightweight requirement. also, magnesium has good specific strength and absorbs vibration in occurring working process. So, it has good quality of product processing. And then, it is one of the lightest materials being used to electronic product's cases and automotive because of lightweight and miniaturization. But this material has not widely used all of the industry due to its natural property. If the magnesium is contacted water, it will cause the exploration. But, nowadays many of people study magnesium to safe their experiment and to widely use this industry.

• 한국화재소방학회논문지
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• 제15권3호
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• pp.70-76
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• 2001

현 사회는 안락과 안전을 중요시하고 있다. 그 중, 가장 중요한 부분의 한 부분이 각 건축물에 설치되어 있는 소방시설의 관리와 방화훈련이 얼마나 잘 관리되고 평소 훈련이 되어있는가에 따라서 화재시에 인명과 재산상의 피해를 극소화 할 수 있다. 따라서, 본 연구에서는 공동주택, 상가건축물 및 사무소건축물 등의 소방시설의 점검실태를 설문 조사하였으며, 화재시에 대피훈련을 얼마나 숙지하고 있는가를 조사. 분석함으로써 화재시 손실을 최소화 할 수 있는 방법과, 실질적인 점검 및 훈련방법을 제시한다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.1038-1042
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• 2002

Monitoring of the drill wear and hole quality change is conducted during the drilling process. Cutting force measured by tool dynamometer is a evident feature estimating abnormal state of drilling. One major difficulty in using tool dynamometer is that the work piece must be mounted on the dynamometer, and thus the machining process is disturbed and discontinuous. Acoustic transducer do not disturb the normal machining process, and provide a relatively easy way to monitor a machining process for industrial application. For this advantage, AE signal is used to estimate the abnormal state. In this study vision system is used to detect flank wear tendency and hole quality, there are many formal factors in hole quality decision circularity, cylindricity, straightness, and so on, but these are difficult to measure in on-line monitoring. The movement of hole center and increasement of hole diameter is presented to determine hole quality As the results of this experiment, AE RMS signal and measurements by vision system are shown the similar tendency as abnormal state of drilling. And detection of the abnormal states using BPNs was achieved 96.4% reliability.

• 한국생산제조학회지
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• 제5권2호
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• pp.46-56
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• 1996

Drilling tests were carried out austempered ductile castiron(ADI) to clarify the factors influencing the drilling characteristics of ADI material. The machinability of material was evaluated using high speed steel drill and cobalt contained drill of 6mm diameter. The spheroidal graphite cast iron materials were austenized at 90$0^{\circ}C$ for 1 hour and then wear was kept at 375$^{\circ}C$ for 2 hours. Austempered ductile cast iron contains a great deal of retaine austenite which contributes to an improvement of impact strength, In this paper, machinability of ADI was investigated by drilling experimentation. The results obtained are as follows: a)Flank wear increases logarithmically with the increases of cutting time. b) Relation of flank wear and cutting force can be appiled to $F_z$ = 925VB + 820 for the cutting suggested condition. c) Drilling hole number of about 2 times can be reduced more step feed than ordinary feed due to the high hardness of ADI material and hardness increasing ascribed to the martensite of retained austenite.

• 지질공학
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• 제7권1호
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• pp.11-26
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• 1997

한.독 국제공동연구를 통하여 현실화된 코아스캐너는 세계적인 현기술수준에서 독보적이라 할 수 있다. 발췌된 코아의 외형은 촬영되고 또한 디지털 데이터화 함으로써 다음과 같은 기대효과가 약속되고 있다. $\circled1$ 거의 완벽한 코아 외형복제는 바로 코아 보관에 따른 제반 문제를 극복할 수 있는 기틀을 마련하는 것이 되겠으며, $\circled1$ 재래의 시추주상도가 보여준 불확실성은 다각적인 분석기법 내지 다양한 도면화기법에 의해 크게 해소됨으로써 향후 지질주상도 작성을 위한 새로운 면모를 보여 주는 것이 되었다. 본 논문에는 상기 기법이 국내 변성퇴적암 코아에 응용되어 그의 효율설이 입증되고 있음을 보여주고 있다.

• 대한기관식도과학회지
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• 제14권1호
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• pp.50-53
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• 2008

Subcutaneous cervicofacial, mediastinal emphysemas are complications associated with head and neck surgery, trauma, infectious processes, tooth extraction. Drill cooling stream and dental syringe air ject are the sources of high pressure air that may enter exposed soft tissue. Since the introduction of the high-speed air turbine drill in the 1960s, The incidence of iatrogenic subcutaneous emphysema has increased. Most cases begin to resolve after 2 to 3 days and residual swelling is usually minimal at the end of 7 to 10 days. Surgical approach is not advised because it is likely to be ineffective. The differential diagnosis of neck swelling after dental procedure includes hematoma, cellulitis, angioedema, allergic reaction, subcutaneous emphysema. We report a rare case of patient with subcutaneous cervicofacial emphysema and mediastinal emphysema secondary to third molar extraction.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.842-846
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• 1997

Micro-hole drilling (holes less than 0.5 mm in diameter with aspect ratios larger than 10) is gaining increased attention in a wide spectrum of precision production industries. Alternative methods such as EDM, laser drilling, etc. can sometimes replace mechanical micro-hole drilling but are not acceptable in PCB manufacture because they yield inferior hole quality and accuracy. The major difficulties in micro-hold drilling are related to wandering motions during the inlet stage, high aspect ratios, high temperature,etc. However, of all the difficulties, the most undesirable one is the increase of drilling force as the drill penetrates deeper into hold. This is caused mainly by chip related effects. Peck-drilling is thus widely used for deep hole drilling despite the fact that it leads to low productivity. Therefore, in this paper, a method of cutting force regulation is proposed to achieve continuous drilling. A proportional plus derivative (PD) and a sliding modecontrol algorithm will be implemented for controlling the spinle rotational frequeency. Experimental results will show that sliding mode control reduces the nominal cutting force and its variation better than the PD control, resulting in a number of advantages such as an increase in drill life, fast stabilization of the wandering motion, and precise positioning of the hole.

• 한국생산제조학회지
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• 제7권4호
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• pp.56-63
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• 1998

The purpose of this is to analyze experimentally how the change of cutting speed have effects on hole over size of cutting hole, surface roughness of workpiece and roundness during the deep hole machining of SM55C with solid BTA drill using BTA drilling system. Conclusion reached is as follows. (1) The diameter was expanded for 25$\mu$m at the first section and then was reduced 0$\mu$m and 15$\mu$m respectively at the 10m and 20m section comparing to the diameter of tool with respect to the variation of cutting length at 70m/min of cutting speed. 0.15mm/rev of feed. (2) It was proved that roughness was below 8.67$\mu$m for the whole section of cutting length. (3) The roundness has been below 12$\mu$m. Regarding the polygon phenomenon, it has been proved that not only uneven best at 70m/min of cutting speed. 0.15mm/rev of feed.