電力電子 回路의 디지탈 시뮬레이션에 관한 硏究

윤병도,정태경,황선진 중앙대학교 기술과학연구소 1989 기술과학연구소 논문집 Vol.19 No.-

In recent, due to the advanced development of the power semiconductor devices, the digital simulation becomes essential in order to investigate the behavior of the sytem before the manufacturing of the system by using computer for design and analysis of power electronic systems. This paper develops the program, so-called PECA, which can be applied for the power electronic circuits composing of power transistors, thyristers, GTO's and power FET, etc.. Also, the method of using computers for the analysis of power electronic circuits is considered. Finally, we consider both transistor DC chopper circuit and thyristor bridge circuit and prove the effectiveness of the program by both the experiment and simulation.

철근콘크리트 장방형 전단벽의 비선형 유한요소 해석

윤현도,한민기,김선우,박완신,양일승,한병찬 대한건축학회 2005 大韓建築學會論文集 : 構造系 Vol.21 No.2

The major objective of the present study is to conduct parametric study and to propose a finite element analysis(FEA) technique of the reinforced concrete rectangular shear walls using ABAQUS under constant axial and monotonic lateral load. A FEA of the reinforced concrete walls are different to aspect ratio and a detailed finite element models are created to study the post-cracked mode of failure in plastic region of the walls. The proposed models account for the effect of material inelasticity, concrete cracking, and geometric nonlinearity. The prossed FEA model is verified by Lefas's benchmark data and validated through comparisons with experiment result of reinforced concrete shear walls. Finally, the study considered various parameters and compared with ACI 318-02 to confirm accuracy of this study: aspect ratio, axial force ratio, vertical and horizontal reinforcement ratio.

철근콘크리트 연속보에서 부분프리스트레스 도입에 의한 휨보강 효과에 관한 연구

한병찬,윤현도,박완신,황선경,임재형,문정호 대한건축학회 2004 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.24 No.1(구조계)

A strengthening technique for reinforced concrete beams using external unbonded reinforcement offers advantages in speed and simplicity of installation over other, established, strengthening techniques. The purpose of this paper is to investigate the capabilities of a new retrofitting technique, namely external prestressing(Bow), for flexural strengthening of beams. The paper provides a general description of structural behavior of beams strengthened using the technique. Results of 2 physical tests on strengthened reinforced concrete continuous beams are reported and compared. It is shown that the technique can provide greater strength enhancement to lightly reinforced sections and that provision of deflectors enhances efficiency.

변색 실활치에 대한 carbamide peroxide gel의 표백효과

박선아,김선호,황윤찬,오병주,윤창,박영준,정선와,황인남,오원만 大韓齒科保存學會 2002 Restorative Dentistry & Endodontics Vol.27 No.4

The bleaching of discolored nonvital teeth is conservative treatement that satisfy the cosmetic desire. The most common method for this treatement, walking bleaching, is using 30% hydrogen peroxide and sodium perborate. Many alternatives are suggested for preventing the external cervical root resorption that is the common complication of the nonvital teeth bleaching with 30% hydrogen peroxide. The same extent of oxidation reactions as that resulted by the bleaching with the application of 30% hydrogen peroxide and sodium perborate can also be acquired more safely by materials that contain 10% carbamide peroxide, used primarily for the bleaching of vital teeth. Therefore, this study was performed to evaluate the efficacy of 10% and 15% carbamide peroxide bleaching gel in nonvatal teeth bleaching. The internal bleaching of intentionally discolored teeth was performed in vitro with 10% carbamide peroxide (Group 1), 15% carbamide peroxide (Group 2), mixture of distilled water and sodium perborate (Group 3), and mixture of 30% hydrogen peroxide and sodium perborate (Group 4). The bleaching materials were refreshed following 3, 6, 9 and 12 days. To evaluate the bleaching effect, the color change of the crowns was measured at 1, 2, 3, 4, 7 and 15 days of bleaching using the colorimeter. The results were as follows : 1. L^* and ΔE^* values were increased with time in all bleaching agents(p<0.01). 2. There was no significant difference in L^* and ΔE^* value among bleaching agents. 3. Δ^* value higher than 3 was shown after 3 days of bleaching with 10% carbamide peroxide gel, 1 day with 15% carbamide peroxide gel, 4 days with mixture sodium perborate and distilled water and 4 days with mixture sodium perborate and 30% hydrogen peroxide, respectively. These results revealed that the use of 10% and 15% carbamide peroxide bleaching gel in non-vital teeth bleaching is as effective as mixture of distilled water and sodium perborate and mixture of 30% hydrogen peroxide and sodium perborate. Accordingly, carbamide peroxide could be used clinically to bleach discolored non-vital teeth.

재생골재 콘크리트 보강블록을 이용한 증설벽의 구조성능

김선우,이갑원,박완신,한병찬,최창식,윤현도 대한건축학회 2004 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.24 No.1(구조계)

The use of recycled aggregate concrete is increasing faster than the development of appropriate design recommendations. Also noises and shocks caused remodeling and reinforcement work do harm to residents. This paper reports limited experimental data on the structural performance of shear wall used concrete blocks made in recycled aggregates. Reinforced concrete frame and shear wall were tested to determine their diagonal cracking and ultimate shear behavior. The variable in the test program was the existence of infilled wall used concrete blocks Made in recycled aggregates. Based on the experimental results, Infilled wall has a high influence on the maximum strength and initial stiffness of reinforced concrete frame. Structural performance of specimen WSB is quite different from RCF specimen, particularly strength, stiffness and energy dissipation capacity.

심근 허혈-재관류 백서 모델에서 mitogen-activated protein kinase 활성화에 대한 α-lipoic acid의 효과

김연경,박은미,최준호,윤경호,유남진,이은미,김남호,정진원,김민선,박병림,오석규 圓光大學校 醫科學硏究所 2006 圓光醫科學 Vol.21 No.1

Nutcracker 증후군의 진단에 있어서 도플러 초음파검사의 유용성 : Diagnostic Usefulness of Doppler US

박병관,김승협,조정연,성창규,박선원,한만청 대한초음파의학회 1998 ULTRASONOGRAPHY Vol.17 No.2

高靭性 纖維補强 시멘트 複合體를 使用한 耐震要素의 履歷特性

양일승,윤현도,김선우,박완신,한병찬,문연준 대한건축학회 2005 大韓建築學會論文集 : 構造系 Vol.21 No.1

Concrete is one of the principal materials for the structures and It is widely used all over the world While advanced technologies of concrete have been recently focused especially on developing high performance concrete In which possess high compressive strength and durability, such concrete shows extremely brittle failure under shear and tension To Improve such a poor properties, high performance fiber reinforced cement composites(HPFRCC) has been developed For forming multicrack, a large number of fiber and/or the high specific area with thinner fibers are required However, It causes difficulties for the extrusion because of the poor workability So, this theses was suggested adequate mixing method and mix proportion for cach fibers and experimentally observed Structural performance of the seismic devices made by steel bar and HPFRCC These dampers will be applied for reducing damage as weil as seismic response The advantages of the HPFRCC damper is selective structural performance, strength, stiffness, and ductility by changing configuration, bar arrangements and type of materials used The experimental results indicate that elemental ductility is much increased with decreasing damage when the HPFRCC are applied to the damper It means cementitious seismic damper for structure control is available, which has much merit in performance and cost

응급의학과 전공의 교육을 위한 제언

백광제,박승희,선경,장연희,엄병선,홍윤식 대한응급의학회 1993 대한응급의학회지 Vol.4 No.2

Although the medical science in Korea has experienced remarkable development, both qualitatively and quantitatively, since its introduction at the beginning of the 20th century, its main focus has been on the expansion of spcialized treatment and medical care in general. However, the fast-paced economic development that started in the 1960's has caused substantial increases in cerbrovascular disease and coronary artery disease while the industrial development and in creased use of means of transportation have resulted in the rapid rise of incidents in external injuries. Consequently, the public has become acutelyh aware of the need for fast and effective emergency transportation and treatemnt. Such awareness also stems from the wide avalilability of medica care which is now established as a basic citizen's right as a result of the national medical insturance system that started in 1977 and was fully implemented in 1989. In response to the public demand for effetive emergency treatments, kthe health care sector has been making serious efforts to deliver better emergency treatments by expanding the emergency facilities and newly offering emergency training programs. Several hospitals have already commenced training programs in order to provide personnel specially trained in that area. The emergency medicine requires not only specialized training in the emergency treatment program in emergency should be designed in order to adapt to the specific needs of the Koreans, as based on epidemiological studies of the nature of emergency cases, its distribution in the population by ages and nature of injury, admission ratio, death rates, etc. currently prevailing in Korea. The present research has been carried out by the Korea university Hospital in preparation of the commencement of the emergency training program in 1994. The research consists of analysis of the emergency cases admitted in the Emergency center of Korea University Hospiatl from January 1992 to December 1992, its distribution, nature, and statistics regarding admission. Based on our research and our review of other available literature on the subject, we make the following suggestions regarding the specialized training program for emergency treatment. 1. The trainees must be required to be also t4rained in the areas of internal medicine surgery, obstetrics and pediatrics. 2. The training in internal medicine should include gastrointestinal, espiratory, cardiovascular medicine and nephrology which the training in surgery should include general surgery, neurosurgery and cardiac surgery. 3. The program should provide training for effective and accurate reading of the radiology. 4. The trainees should be required to participate in actural emergency treatment activities in order to have opportunities to acquire practical skills as well as theoretical knowledge. 5. The program should include course in medical management which would be necessary for effective management and administration of emergency centers and facilities. 6. The continued development of the program would require extensive studies and researches supported by the academic associations of medicine.

백서에서 Depulpin®과 Formocresol에 대한 치수와 치근단 조직의 반응

문형인,김선호,황윤찬,오병주,황인남,김선헌,정선와,윤창,오원만 大韓齒科保存學會 2002 Restorative Dentistry & Endodontics Vol.27 No.4

One fifth dilution of formocresol is usually for pulpotomy of the primary teeth and emergency pulpotomy of the permanent teeth. However, the use of formaldehyde has been subjected to criticism because it may be absorbed into the blood stream and become distributed systemically, it may also alter the pulp tissue rendering it immumologically active, and have carcinogenic potential. Recently Depulpin®(VoCo., Germany) gains popularity as a devitalizing agent during root canal therapy in spite of high concentration of 49% paraformaldehyde because it facilitate devitalization of pulp and make root canal therapy easier. But there have been not enough publications about the reaction of pulp and periapical tissue caused by Depulpin. This study was performed to evaluate the histological changes in pulp and periapical tissue of rats after pulpotomy using formocresol and Depulpin and to elucidate the toxic effects of these agents. Thirty six Sprague-Dawley rats were anesthetized by intraperitoneal injection of ketamine. Maxillary first molar teeth were used for pulpotomy with formocresol and Depulpin. Rats were sacrificed after 2 days, 4 days, 1 week, 2 weeks, 3 weeks and 4 weeks respectively. Specimens were histologically observed by light microscope changes in pulp and periapical tissue. The obtained results were as follows. 1. Formocresol group A zone of fixed tissue, in which odontoblasts could clearly be defined, was present directly underneath the pulpotomy dressing in almost all teeth of this group. This was followed by an area of necrotic tissue which resembled dried out fibrous tissue with no cellular detail except some pyknotic nuclei. In the specimens of after 2 days, 4 days, 1 week, 2 weeks in which vital tissue was present. it was separated from the fibrous area by a zone of inflammation. In the specimens of after 3 weeks and after 4 weeks, inflammatory infiltrate was in the periodontal ligament adjacent to the apical foramina of the teeth. 2. Depulpin® group The area of necrotic tissue which had no cells and fibers , was present adjacent to the dressing. This was followed by dried out fibrous tissue with no cellular details except some pyknotic nucleli. A short stump of vital pulp with odontoblasts was present at the end of the canal after 2 days. Inflammatory infiltrate was in the periodontal ligament after 4 days and after 1week. Severe root resorption and necrosis of periapical tissue opposite the root resorption site were defined after 2 weeks and after 3 weeks. Periapical lesion which consist of necrotic tissue surrounded by a fibrous connective wall. was found after 4 weeks. The results indicated that Depulpin can cause more adverse reaction to the dental pulp and periapical tissue than formocresol, and further studies are needed for its clinical use with safety.