적외선 유도 미사일은 미사일에서 자체적으로 방사하는 신호가 없어 항공기에서 접근을 인지하고 대응하기가 어렵다. 또 한 적외선 유도 미사일을 탐지하는 MAW(missile approach warning)는 고가의 장비로 현재는 항공기에의 사용이 제한되고 있으며 그 효용성이 공개된바가 없다. 따라서 본 연구에서는 MAW가 탑재되어 항공기가 접근하는 유도 미사일에 대해 회피 기동을 수행할 때 항공기의 생존성이 얼마나 증가하는지를 해석하여 MAW의 효용성을 평가하고자 하였다. 생존성의 평가 지표로 위험 거리를 사용하였으며 고도 5km를 마하 0.9로 비행하는 항공기에 대해 AIM-9 적외선 유도 미사일이 접근하는 상황에 대한 위험 거리를 방위각 별로 도출하였다. 항공기의 회피기동에 대한 변수로는 5～7km의 MAW 인지거리와 3～7G 의 항공기 기동성능을 고려하였다. 해석 결과 MAW를 통한 미사일 접근 인지와 회피기동 만으로도 위험 거리가 상당히 감소하는 것을 확인했다. 회피기동에 따른 위험 거리의 감소는 최대 29.4%로 나타났다. 또한 상대적으로 향상시키기 어려운 항공기 기동성능보다는 MAW 인지거리를 증가시키는 것이 위험 거리의 감소에 더 효과적인 것으로 나타났다.

본 논문에서는 과도한 계산용량이 필요한 초음속 비행체의 비정상 열응답 해석을 수행하기 위한 준-비정상해석 기법을 소개한다. 준-비정상해석 기법은 연성 연계 기법과 복합 열전달 해석기법을 통합한 방법으로 계산시간 단축시키면서 동시에 정확도를 향상시키기 위해 고안되었다. 또한 준-비정상해석 시, 해석 구간을 분할하기 위한 기준시간을 결정하는 알고리즘을 고안하여 준-비정상해석 기법의 정확도를 향상시키고자 하였다. 본 논문에서는 준-비정상해석 기법을 평가하기 위하여 가상의 비행 시나리오에서 열응답 해석을 수행하였으며, 비정상 해석 결과와 비교 검증을 수행하였다. 무딘 물체의 표면 온도 및 정체점의 온도를 통해 각각의 기법의 차이를 도출하였다. 비정상 해석을 통해 도출한 정체점의 온도와 준-비정상 해석을 통해 도출한 정체점의 온도 차이는 11.4% 이내로 높은 정확도를 확보함과 동시에 28배에 가까운 계산시간을 단축시켜 해석 기법의 효율성과 정확성을 확보하였다.

Ablative material in a rocket nozzle is exposed to high temperature combustion gas, thus undergoes complicated thermal/chemical change in terms of chemical destruction of surface and thermal decomposition of inner material. Therefore, method for conjugate analysis of thermal response inside carbon/phenolic material including rocket nozzle flow, surface chemical reaction and thermal decomposition is developed in this research. CFD is used to simulate flow field inside nozzle and conduction in the ablative material. A change in material density and a heat absorption caused by the thermal decomposition is considered in solid energy equation. And algebraic equation under boundary layer assumption is used to deduce reaction rate on the surface and resulting destruction of the surface. In order to test the developed method, small rocket nozzle is solved numerically. Although the ablation of nozzle throat is deduced to be higher than the experiment, shape change and temperature distribution inside material is well predicted. Error in temperature with experimental results in rapid heating region is found to be within 100 K.

Krox-25, a Kruppel type zinc finger protein, may play an important role for the morphogenesis of tooth in ectomesenchymal interaction between enamel epithelium and odontogenic mesenchyme. The interrupted expression of Krox-25 by antisense inhibition is supposed to affect the abnormal development of tooth germ similar to the deranged proliferation of odontogenic tumors. This study was performed to know the histomorphogenetic effect of Krox-25 antisense inhibition in tooth germs of mouse embryos and to understand the abnormal expressions of Krox-25 in different odontogenic tumors which proliferate in aberrant direction of ecto-mesenchymal interaction. Total 95 tooth germs obtained from pregnant mice in the 13th day of fertilization were cultured with antisense oligonucleotides targeting mouse Krox-25 gene, and their histological patterns were compared with those of different odontogenic tumors, i.e., ameloblastic fibro-odontoma (n=5), ameloblastoma (n=8), and ameloblastic carcinoma (n=2). Resultantly, the cultured tooth germs treated with antisense oligodeoxynucleotides produced primitive dentine and enamel by odontoblasts and ameloblasts, respectively, but they aberrantly grew and formed abnormal tooth organs. Especially, the harmonious growth of enamel and dentine formation was greatly deranged by the antisense inhibition in the organ culture system. These findings were much similar to the abnormal growth of odontogenic tumors. The relatively well differentiated enamel epithelium of ameloblastic fibro-odontoma showed irregularly strong reaction of Krox-25, while the poorly differentiated enamel epithelium of ameloblastic carcinoma showed weak reaction. These data suggest that Krox-25 may play important roles for the histomorphogenesis of tooth germ by signaling the ecto-mesenchymal interaction between odontoblasts and ameloblasts in normal tooth germ development of mouse embryos as well as in cytodifferentiation of odontogenic tumors.

A case of chronic osteomyelitis caused by prolonged intake of bisphosphonate showed multiple recurrences involving extensive area of mandibular body. After saucerization the removed bony fragments were decalcified, microsected in 4 ㎛ thickness, and stained with hematoxylin and eosin, Masson trichrome, von Gieson, and periodic acid Schiff reaction. The inflammatory lesion contained fragile osteophytes easily propagated into sequestra. Histologically, this osteomyelitis was relatively less suppurative but almost granulomatous, highly infiltrated with small round cells and macrophages. The osteophytes were frequently deposited on the old lamellate bone, but their ossification was extremely immature and frequently filled with sclerosed collagen bundles positive for von Gieson stain. In the polarizing microscope observation under Masson trichrome stain the newly deposited osteophytes were lack of birefringence image of Haversian system contrast to the old bone nearby. Therefore, we presume that the prolonged intake of bisphosphonate may induce the immature osteophytes lack of Harversian system, which are partly filled with sclerotic collagen bundles, and the immature bone is easily undergone extensive degeneration and necrosis, resulted in the inflammatory foci for multiple recurrent osteomyelitis.

Although the sparganosis involving soft tissues, i.e, tongue, cheek, etc., has been frequently reported, the mandibular involvement of sparganosis is not reported up to date. We present a case of intraosseous sparganosis involving whole mandible, which was clinically diagnosed as chronic osteomyelitis. After surgical operation of saucerization for the treatment of chronic osteomyelitis the removed specimens were pathologically examined and finally turned out intraosseous sparganosis. Radiological findings showed irregular multiple radiolucencies in round to ovoid shape throughout both mandibular body areas, of which peripheral rarefying radiopacity was less remarkable compared to the ordinary osteomyelitis. However, the radiolucencies of periapical granuloma, #34-36, were closely associated with the osteolytic lesions of mandibular body. Pathological examination showed a tunnel like space for the passage of sparganum larva, and heavy infiltration of eosinophilicleukocytes. And more, the parasitic tegument materials were found admixed with eggs in the granulomatous lesion, which were gradually degraded and resolved. Taken together, we presumed that the mandibular inflammatory lesion was primarily involved with sparganosis and secondarily aggravated by the periapical infection of #34-36.

35 peri-implantitis recently referred for 10 years showed four types of inflammatory lesions, such as mild granulomatous lesion(n=5), severe granulomatous lesion(n=4), severe inflammatory fibrous scar tissue(n=15), severe abscess formation(n=11). However, the inflammatory lesions were usually localized at the peri-implant area accompanying compensatory hyperplasia of fibrous connective tissue. The fibrous scar and the necrotic abscess frequently occurred depend on the severity of inflammatory reaction. Among 30 cases of severe inflammatory lesions, only 2 cases involved condensing osteitis in adjacent alveolar bone. Thus, we suppose that the inflammatory progression of peri-implantitis could be partly inhibited by the hyperplastic fibrous stromal tissue stimulated by implant material. And more, the focal abscess formed around the implant can be easily drainaged through the fibrous tract of implant pathway, resulted in the chronic persistent inflammatory granulomatous lesion, that is contrast to the common socket granuloma after tooth extraction. However, depend on the degree of inflammatory reaction in the peri-implantitis the inflamed fibrous collagenous tissues, unregenerated graft materials, necrotic abscess and sequestra should be removed by surgical intervention and followed by antibiotic therapy, because the peri-implant tissue is as vivid as the normal periodontium for the inflammatory defense system. Therefore, we suggest that the inflammatory lesions of peri-implantitis be carefully treated to improve the prognosis for the following dental treatments

This study analyzes the factors involving clinical practice which have an influence on the satisfaction of students majoring in physical therapy at colleges or universities located in the Pusan and Kyungnam area. We investigated using a self-reporting method 305 students receiving a grade point average between 2.0 and 4.0 and who had finished their clinical practice. We also investigated the characteristics of clinical settings which make up the clinical practice, the general characteristics of the students involved and the characteristics of a clinical teaching method performed by physical therapists versus a teaching method by a professor of a university. The number of students divided according to educational background are as follows: 149 people (48.9% of the total group) were 4 year students, 156 people were 3 year students (51.1% of the total group). Sixty-nine students' or 22.6% of the group were men while women consisted of 236 persons or 77.4% of the group. Four year students had a longer clinical practice period than that of the 3 year students (p<.05). An average satisfaction score of students with their clinical practice was 3.84. The satisfaction scores showed no significant difference between genders, educational backgrounds, and grades. (p>.05). There were no significant differences in the satisfaction score of students with their clinical practice was 3.84. The satisfaction scores showed no significant difference between genders, educational backgrounds, and grades. (p>.05). There were no significant differences in the satisfaction scores regarding the student management system among varying gender or educational backgrounds between the 3 year and 4 year programs. The average satisfaction score with the environment of the physical therapy room was 3.35. And there were no significant differences in the physical therapy room satisfaction score based on sex or educational system (p>.05). The most influential factor of determining clinical practice satisfaction was a student management system of the clinical practice (p<.01). The next most influential factors were the clinical practice period (p<.05), size of facilities (p<.01) and relationship with physical therapists (p<.01) (=.554).