• Maxillofacial Plastic and Reconstructive Surgery
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• 제28권1호
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• pp.49-57
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• 2006

Mandibular fractures have higher incidence rate compared to facial bone fractures because of relatively prominent form. Specially, mandibular angle fractures were known as common fracture site because of morphological anatomic structure. The mandibular third molar appears to be the most frequent impacted tooth. The mandibular third molar have influence on mandibular angle fractures according to it's eruption state. Also, the mandibular angle fracture including the third molar may influence on post operative infection whether the third molar is in impacted or extracted state when reduction of fracture site is operated. The presence or absence and degree of impaction of the mandibular third molar were assessed for each patient and were related to the occurrence of the mandibular angle fracture. The extraction or non extraction of the mandibular third molar were related to the occurrence of the post operative infection in the reduction of mandibular angle fractures. In the presence of mandibular third molar, the possibility of mandibular angle fractures were relatively common. When viewing the mandibular third molar at occlusal plane, the possibility of mandibular angle fractures were high in the class C group. The possibility of mandibular angle fractures were high in the mesial angulation and partial impaction. There was a statistically significant difference(P<0.05). In complete erupted mandibular third molar, the possibility of post operative infection occurs quite often, but there was no statistical significant difference(P>0.05). In the extracted or non extracted of mandibular third molar, the post operative infection showed no statistical significant difference(P>0.05). With the results mentioned above, mandibular third molar was significantly more susceptible to mandibular angle fracture. In the reduction of mandibular angle fracture, it was recommended that mandibular third molar should be extracted especially in case of pericoronitis, periodontitis and other infections.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제29권4호
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• pp.239-244
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• 2003

The common errors in preoperative treatment plan for the orthognathic surgery can be occurred during cast impression, cast mounting procedure with face-bow transfer, surgical stent fabrication, and so on. One of the most common errors exists during mounting process of the model on the articulator. Accurate mounting of dental casts to articulator should be achieved by transferring the 3-dimensional spatial relationship of the maxillary arch to an articulator. A face-bow is used for transfer this relationship to articulator, usually by relating the face-bow to a plane of reference of maxillary cast. The purpose of this study is evaluation of the accuracy of face-bow transferring of maxillary model to the articulator. The maxillary casts of thirty patients for orthognathic surgery were mounted on articulator with an face-bow instrument. The relationship of occlusal plane angle to Frankfort horizontal plane relations were compared the cephalogram with the cast-mounted articulator. As a result of this study, the significant difference between the maxillary occlusal planes angle in the cephalogram and articulator were found. The results were followed, 1. The mean occlusal plane angle in cast-mounted articulator was $13.5^{\circ}\;(SD{\pm}5.4)$. 2. The mean occlusal plane angle in cephalogram was $10.4^{\circ}\;(SD{\pm}4.3)$. 3. The mean difference of occlusal plane angle between cast-mounted articulator and cephalogram was $3.3^{\circ}\;(SD{\pm}4.6)$. According to the result, we should suggest that the occlusal plane angle to Frankfort plane in cast-mounted articulator is more steeper than that of cephalogram. And then, maxillofacial surgeon should try to get a more predictable result by suggesting the proper correction method and mounting the cast accurately.

• Composites Research
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• 제30권3호
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• pp.202-208
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• 2017

RTM은 작은 크기에서 큰 크기의 복합재료를 생산할 수 있는 대량 생산 공정이다. 최근 경화 시간이 약 10분 이내인 속경화 수지가 자동차 및 항공우주 산업에 사용되고 있다. 수지의 점도는 경화 정도와 관련이 있으며, 금형 내부로 충진되는 과정에서 급격히 점도가 변할 수 있다. 따라서 속경화 수지의 유동 특성과 경화도를 해석적으로 예측하는 데 많은 노력이 필요하므로 실험적으로 측정하고 평가하는 것이 유리하다. 복합재료의 경화도를 측정하는 방법은 대표적으로 DMA, 유전기법 등이 있다. 본 논문에서는 다채널 경화 모니터링 시스템을 이용하여 속경화 수지의 유동과 경화도를 측정하였다. 총 8채널의 유전센서가 사용되었으며, 다양한 압력 조건에 따른 금형 내부의 유동과 경화도를 측정하고 상호 비교하였다.

• 대한기계학회논문집B
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• 제24권3호
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• pp.390-401
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• 2000

In this study, numerical calculation is carried out to investigate the influence of injection timing, fuel amount, intake $O_2$ concentration, and EGR on Nitric Oxide(NO) formation using a two-zone model in a diesel engine. Results can be summarized as follows. The NO formation is very sensitive to the burned gas temperature, so multi-zone model must be applied to combustion process to predict the burned gas temperature exactly. Since the burned gas temperature increases rapidly during the premixed combustion, most NO is formed within 20 crank angle degrees after ignition. As the injection timing is retarded, the combustion occurs later in the expansion process which causes the decrease of burned gas temperature and, as a result, NO formation decrease. The increase of fuel amount results in the increase of earlier formation of NO in the engine. As the intake $O_2$ concentration increases, the maximum pressure and burned gas temperature increase due to activate combustion. And, [O] mole fraction of equilibrium combustion products also increase. Therefore NO exponentially increases. If exhaust gas is recirculated, the burned gas temperature decreases which results in NO decrease. If exhaust gas is cooled, more NO can be decreased.

• Journal of Preventive Medicine and Public Health
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• 제31권2호
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• pp.215-227
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• 1998

In order to develop the computerized information system of occupational health management at worksite, we surveyed actual states of computer use at worksites. We used a self-administrative questionnaire to the members of Korean Association of Occupational Health Nursing(KAOHN) from July 4 to August 21 in 1997. Among the members of KAOHN, 147 members answered. The worksites where they were employed were very diverse in aspect of jobs, locations, and size. Occupational health computerized system was used at 30(20.4%) worksites among 147 respondants. When they first introduced the computerized system the most difficult problem was the lack of support of manager. The programs that they have used mainly consist of drug management, health examination management, disease management, but the program of worksite environment management have been rarely used. Most users felt that the computerized system was effective, but there were problems in connection within programs. Many worksites have plans to take or expand the computerized information system within several years. It is necessary to develop the effective and integrated occupational health computerized system.

• 한국전자거래학회지
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• 제10권1호
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• pp.41-60
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• 2005

본 논문에서는 국방CALS의 구현을 위한 표준방법론인 ID EF1/1X를 무기체계 연구개발 절차에 적용하여 연구개발 수행과정에서의 연구목표, 정보의 입력, 산출, 제약조건에 대한 정보모델링을 제시하였다. ID EF1/1X를 실행하는 프로그램인 SmartER를 이용하여 연구개발 수행기관 내부에 존재하는 모든 정보자원의 관리에 대한 요구분석을 실시하여 관리해야 할 정보를 식별한 후 TO-BE모델에 대한 정보모델링을 제시한 것이다. ID EF 적용대상인 무기체계 연구개발의 절차는 개념연구, 탐색개발, 체계개발, 그리고 시제품 제작을 거쳐 연구개발 결과 보고서 작성 단계로 구성되어 있다. 본 연구의 정보모델링 결과로 무기체계 통합데이터베이스(IWSDB)를 이용하여 정보를 공유하고 연구개발업무를 수행하는 것을 제시하였다. 무기체계 연구개발사업과 같은 대형 체계개발 사업에 대한 프로세스의 효율성을 기하기 위해서 적절한 방법론으로 알려진 IDEF에 대한 본격적인 연구가 진행되어 국방CALS를 구현하는 계기가 되었으면 한다.

• 식물분류학회지
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• 제32권4호
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• pp.481-489
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• 2002

제주도의 수악계곡과 김녕리에 생육하는 검은별고사리[Thelypteris interrupta (Willd.) K. Iwats.] [처녀고사리과]와 계곡고사리[Dryopteris subexaltata (H. Christ) C. Chr.] [관중과]를 채집하여 국내 미기록종으로 보고하였다. 검은별고사리는 별고사리[T. acuminata (Houtt.) C. V. Morton]와 유사하지만 지하 줄기와 엽병 기부 및 포자의 색깔, 잎 이면의 선모의 유무, 포자낭군의 배열 형태 등에서 차이를 보였다. 계곡고사리는 국내에 분포하지 않는 D. sparsa (D. Don) Kuntze, D. sabaei (Franch. & Sav.) C. Chr., D. yakusilvicola Sa. Kurata와 유사하지만 엽병 기부의 무성아의 유무, 우편의 선단부 모양, 포자낭군의 분포, 포막의 형태에서 차이를 보였다.

• 펄프종이기술
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• 제31권1호
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• pp.39-45
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• 1999

Refining in papermaking plays an important role in changing fiber properties as well as paper properties. The major effects of refining on pulp fibers are internal and external fibrillation, fiber shortening, and fines formation. Many workers showed that internal fibrillation of the primary refining effects was most influential in improving paper properties. In particular, refining produces separation of fiber walls into several lamellae, thus causing fiber wall swelling with water penetration. This leads to the increase of fiber flexibility and of fiber-to-fiber contact during drying. If the fibers are very flexible, they will be drawn into close contact with each other by the force of surface tension as the water is removed during the drainage process and drying stages. In order to study the effect of fiber wall delamination on paper properties, cross-sectional image of fibers in a natural condition had to be generated without distortion. Finally, it was well recognized that confocal laser scanning microscope (CLSM) could be one of the most efficient tool for creating and quantifying fiber wall delamination in combination with image analysis technique. In this study, the CLSM could be used not only to observe morphological features of transverse views of swollen fibers refined under low and high intensity, but also to investigate the sequence of fiber wall delamination and fiber wall breakage. From the CLSM images, increasing the specific energy or refining decreased the degree of fiber collapse, fiber cross-sectional area, fiber wall thickness and lumen area. High intensity refining produced more external fibrillation.

• 펄프종이기술
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• 제39권4호
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• pp.61-67
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• 2007

Paper sludges collected from three different paper mills were physico-chemically analyzed in order to use them as raw materials for making bed soils and seedling pots. The sludge from a fine paper mill contained lots of inorganic pigment particles used for coating, as those from a newsprint mill and a tissue mill had not. It was clearly through XRD analysis confirmed that all sludges included calcium carbonate. The paper sludge from the tissue mill contained the greatest amount of particles, which would contribute to water absorption and nutrient storage. The sludge from the fine paper mill had the highest density due to many inorganic elements. While the ash content and the total nitrogen content were the highest in the sludge from the fine paper mill, the C/N ratio was the lowest in the fine paper mill sludge. All sludges seemed to have insufficient contents of potassium. The sludges from the newsprint mill and the tissue mill showed more silicon contents than that from the fine paper mill. It was concluded that the sludge from the fine paper mill would be able to be the most efficient raw materials for making bed soils and seedling pots and the other two sludges would be more efficient for intensive culture for crops such as rice and grain with additional supplement of nitrogen and other nutrients.

• 펄프종이기술
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• 제39권4호
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• pp.68-75
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• 2007

In order to supplement insufficient nutrients of paper sludges, additional materials such as saw dust and rice husk were added during preparation of bed soils. Rice husk was more finely ground, compared to saw dust. The fine particles of the rice husk prevented their flow in a barrel of the expander. The mixed additives with paper sludges could be used to control the quantity of required nutrients for raising plants. That is, except for potassium and manganese, most of nutrients were decreased with adding the additives to paper sludge. The acidity of the paper sludges mixed with the saw dust or the rice husk was a little decreased with the increased amount of the additives. Differently from the bulk density of the paper sludges, the moisture content and the water absorption rate of the paper sludges were incremented with increasing the additives.