차체 구조의 빔모델링에 관한 연구

최종근,이승훈,최석환 도립 강원전문대학 1998 道立 江原專門大學 論文集 Vol.1 No.1

This paper has been studied to analyze an automotive body structure by means of a simplified beam model rather than a detailed shell model. It has been done to enhance analysis performance to facilitate design changes. Basically automotive body consists of box channel structures and the strain energy for deformation is concentrated in the vicinity of joint area. Therefore analysis errors from beam modeling are due to the difference in strain energy of joint area between beam and shell modeling. Technique using modified section properties has been introduced, and some important nondimensional factors have been also introduced. We have found out the ratio of thickness and section length, t/H is the main factor to decide whether we have to use this new technique in beam modeling of box channel structures with joint. This technique shows the same results from shell modeling within 2 % error, both in static and normal mode analysis for an isolated model.

대기입자 포집에 의한 공기중 최소검출 방사능농도의 결정

최종서,이원근 경희대학교 환경연구소 1997 環境硏究 論文集 Vol.7 No.-

The role of atmospheric radionuclide monitoring system is to measure the airborne radionuclide released from the nuclear explosive test or nuclear facility. Determination of the MDC(Minimum Detectable Concentration)s of 13 important radionuclides is essential for effective operation of the atmospheric radionuclide monitoring system under the CTBT(Comprehensive Test Ban Treaty) requirement. The radon and thron progeny exert a significant effect in determining the MDCs. The optimum decay and counting times were estimated through a series of experiments on the MDC. It was shown from the experimental results that for long-lived radionuclides, the MDCs were decreased slowly by elapsing the decay time, whereas the MDCs of short-lived radionuclides were increased continuously. In addition, the MDCs of most radionuclides are shown to decrease exponentially as counting time increases. By considering these analysis results, the optimum time parameters which could be satisfied with the CTBT technical requirements were determined. As above results, the optimum decay and counting times were selected 22 hour and 18 hour, respectively.

타이어 편마모 해소를 위한 최적차량 구조설계

최종근,김명규,최석환 도립 강원전문대학 1998 道立 江原專門大學 論文集 Vol.1 No.1

This paper has been studied to eliminate the wear of tire on the solid axle type of an automotive. The heavy tracks, different from passenger cars, have a front axle which consists of a solid axle in a shape of I-beam. Therefore, it is difficult to change the fixed angle of camber and king pin once they are assembled. This study has introduced a suitable method to remove the uneven wear of tire by combination of camber and king pin angle at the stage of design. Parametric optimization has been carried out by setting the optimum characteristics for static and dynamic analysis. The static characteristics represents a condition where the tire and ground makes a perpendicular angle, which makes the ground camber to be zero. The optimal dynamic condition is to minimize the lateral force between the tire and ground in dynamic simulations.

니켈기 초내열합금의 고온부식거동에 관한 연구

최승주,이재현,이찬규,김근수,이종훈 國立 昌原大學校 産業技術硏究所 1998 産技硏論文集 Vol.12 No.-

Hot corrosion behavior of the CMSX-2, CMSX-4, Rene 77, Rene 80 Ni-base superalloys was investigated at 900℃ by two different corrosion methods, immersing the samples in Na2SO4-NaCl mixture(immersion test)and coating the salt mixture on the surface of the samples(modified coating test). The effects of corrosion times and salt compositions from 0 to 100 percent in Na2SO4-NaCl mixtures were examined. Experimental results showed that the corrosion depths in the alloys increased with increasing time, and the depths of the modified coating test were shotter than those of the immersion test in the mixed salt. It was found that the depths of CMSX series alloys increasing NaCl contents in the mixtures up to 50% NaCl. Corrosion products of the alloys were composed of Cr, Al, Ti oxides. The oxide scale, such as Cr₂O₃, Al₂O₃, TiO₂, were shown to improve hot corrosion resistance in the fused Na₂SO₄-NaCl mixtures.

특수학교(급) 고등과정 농생명 교과 운영에 대한 담당교사의 인식

최종근,서선진 이화여자대학교 특수교육연구소 2022 특수교육 Vol.21 No.2

연구목적: 이 연구는 특수학교(급) 고등과정에서 농생명 교과 운영에 대한 특수교사의 인식을 알아보는 데 있다. 연구방법: 특수학교(급) 고등과정에서 농생명 교과를 2년 이상 운영한 경험이 있는 특수교사 8명을 대상으로 면담을 실시하고, 지속적 비교 분석 기법을 통한 주제 분석으로 이들이 인식한 농생명 교과의 운영 실태와 개선 방안에 대해 알아보았다. 연구결과: 농생명 교과는 학생들이 직업 적성을 찾거나 성실한 작업 태도를 형성하고, 안전한 자연체험 활동으로서 생물 재배과정에서 성취감을 얻고 책임감을 기르는 데 기여한다. 특수교사들은 농생명 지식과 실습을 연계한 탐구형 학습을 중시하고, 농생명 교과 활동을 다양화하고 최신화하는 노력을 계속하고 있었다. 그러나 농생명 교과에 대한 학교 구성원들의 부정적 인식이나 노작 및 실습지 관리의 어려움, 그리고 교사의 부족한 교과 내용 지식과 낮은 효능감이 교과 운영의 난점으로 지적되었다. 농생명 교과 개선을 위해 장애학생의 경험과 학습에 초점을 맞추고, 과학농업과 도시농업을 강조하며, 교사 전문성을 지원하는 노력이 필요하다. 논의: 직업 기초 기술의 육성 등 농생명 교과가 가진 다양한 교육적 의미를 탐색하고, 특수교육 농생명 교과의 활성화를 위해 교사의 교과 전문성 확대 지원과 학생의 농생명 학습 경험 확충 방안에 대해 논의하였다. Purpose: The aim of this study was to investigate special education teachers’ perceptions of agricultural education implemented for high school students with disabilities. Method: Eight special education teachers who practiced agricultural education in special education classes and/or schools for more than two years participated in either focus group or individual interviews. These interviews were analyzed with constant comparative analysis. Results: It was reported that agricultural education contributed to fostering special education students’ vocational interests and their work habits, and also to learning to become hardworking and responsible for growing crops. The teachers focused on inquiry-based learning connecting agricultural knowledge to farming techniques and also allowed their students to experience up-to-date agricultural activities. The difficulties in implementing agricultural education were negative attitudes toward agriculture, hardship in hands-on education, and lack of pedagogical knowledge and teaching efficacy. To enhance agricultural education in special education, it is important to focus more on students’ experiences and learning, infuse smart farm technology, and facilitate professional development. Conclusion: Discussions and implications for improving agricultural education practices in special education are provided.

數 種 韓藥의 아세틸콜린에스터레이즈 酵素活性에 대한 효과

최재환,김미영,김현미,최훈,전훈,김대근,임종필,임강현 대한본초학회 2002 大韓本草學會誌 Vol.17 No.1

아세틸콜린에스터레이즈(AChE)는 신경조직에 분포하는 효소로 신경전달물질 중 아세틸콜린(ACh)을 분해하는 효소로 시냅스 신호전달체계에 있어 중요한 역할을 하는 효소이다. 현재 알츠하이머병과 치매치료에 사용하는 서양약물은 AChE의 활성을 저해하는 작용기전을 가진다. 목적 : 전통적으로 기억력 감퇴, 치매 등 치료에 사용되어 온 한약의 AChE에 대한 작용을 밝히기 위해 본 실험이 구상되었다. 방법 : 생쥐 대뇌신경세포의 균질 혼합액으로부터 효소의 활성을 Ellman 방법을 개선한 엘리자(ELISA)법을 이용하여 측정하였다. 결과 : 실험결과 天花? 의 6종이 2.5㎎/㎖의 농도에서 우수한 효소활성저해력을 보였고, 50% 효소활성 저해농도(ID_50)를 구한 결과, 天花?의 ID_50은 1.5㎎/㎖이었고, ??? 1.2 ㎎/㎖, ?? 2.0 ㎎/㎖, ??草 1.2 ㎎/㎖, ??? 1.0 ㎎/㎖, ??生 1.7㎎/㎖, 및 大?皮 2.0 ㎎/㎖를 나타내어 忍冬?의 저해력이 가장 우수하였다. 결론 : 치매 및 기억력감퇴 증상을 치료하는 한약의 작용기전 중 AChE 효소활성억제효과는 忍冬? 의 6종에서 나타났으며, 이는 전통적인 한방치료에 과학적인 기초자료를 제공할 것으로 생각한다.

6주간의 淸暑益氣湯 經口投與가 에너지대사 및 호르몬 변화에 미치는 영향

최용어,강명신,유종만,이규성,오재근,조준용 韓國體育大學校附屬 體育科學硏究所 1994 韓國體育大學校附屬 體育科學硏究所論文集 Vol.13 No.1

The purpose of this study was to investigate the effects of chung-seo-ik-gi -tang administration on the metabolic responses and hormones in 18 healthy-male elite boxes. All subjects were divided randomly with two groups, Chung-sea-ik-gi-tang Group(N=18) and placebo group(N=18) and perfored with 70% of HR max using bycicle ergometer unfil exhaustion. During the submaximal exercise, heart rate was maesured every two min. The blood samples were collected from antecubital vein by 10ml syranges(6ml/each) before immediately after exhaustion, recover-10 min, recover-20 min and recover-30 min. The samples were to analyzed for the level of glucose, lactate, TG, TC, HDL-C, insulin and catecholamine. The results of various blood parameters were summarized as follow; l. Energy substrates (plasma glucose, TG, TC, HDL-C) changes in group C were significantly different from group P. Plasma glucose in group C was significantly lowered at recover-10 min compared to group P (P<0.05). and also TG, TC and HDL-C in group C were significantly increased after 3 weeks compared to group P (P<0.05) whereas. Lactate accumulation in group C was significantly decreased after 3 weeks compared to group P (P<0.05). 2. Plasma insulin level was not showed significant difference between two groups. But insulin depression tendency after 3, 6 weeks in group C was allevated compared to group P. Increasing rate of norepinephrine in group C at Post-exhaustion after 3weeks lowered compared to group P. Norepinephrine in group C at rest periods after 3 weeks showed significant difference compared to group C. The results indicated that Chung-seo-ik-gi-tang had the effects of ergogenic aids on fatigue resistance and recovery from exhaustive exercise at the level of 70% HR max.

장애학생을 위한 검사 조정과 학업성취 수준 분석

최종근,김동일,김은주 국립특수교육원 2005 특수교육연구 Vol.12 No.1

본 연구는 장애학생들이 국가수준 학업성취도 평가에 본격적으로 참여하기에 앞서, 이들 장애학생들에게 요구되는 검사 조정 방안을 모색하고 이들의 기초학습 및 기본학습 능력 수준을 파악하기 위하여 이루어진 전국규모의 조사연구이다. 본 연구를 위해 일반학생 520명과 전국 29개 특수학교 중등부 3학년 학생(시각, 청각, 지체부자유) 144명의 성취수준과 부진학생 비율을 비교하였다. 분석 결과, 한국 장애학생의 기초학습 부진학생 비율은 일반학생의 3-5% 내외에 비해 훨씬 많은 30-50% 안팎에 이르고, 기본학습부진학생(보충학습 대상자) 비율도 일반학생의 10% 내외에 비해 훨씬 많은 60-70% 안팎에 이르는 것으로 나타났으며 특히 청각장애학생의 학업성취수준이 낮은 것으로 나타났다. 따라서 향후 정책적인 측면에서 장애학생들의 기초학습 기능 및 학업성취 수준을 향상시키기 위한 교육의 질 제고에 초점을 두어야 할 것이다. The purpose of this study was to compare the basic learning skill and academic achievement test score of students with disabilities(SWD) with those of general education students', and to identify the change of request for test modification or accommodations(TA) of SWD before and after the test. The participants of this study were 144 9th-grade SWD(the visually impaired, the hearing impaired, and the physically handicapped) from 29 special schools nation-wide, and 520 9th-grade general education students from a school from metropolitan area. In this study, SWD could choose any kind of TA among presentation, response, timing or scheduling, and setting/others. The results could be summarized as follows: (a) Compared to general 3-5%, 30-50% of SWD were categorized as defecting basic learning skill, and compared to general 10%, 60-70% of SWD were categorized as underachievers(in reading, writhing, and math). (b) SWD requested unexpectedly various test accommodations. (c) In order to attain the "appropriate" TA, a well-designed research on impacts of TA should be conducted in the future.

Comparison of Hanwoo with Holstein of OPU derived Embryo and Offspring Production

Jong‐In Jin,Byung‐Hyun Choi,Seong‐Su Kim,Hyun‐Tae Jo,Il‐Keun Kong 한국동물생명공학회(구 한국동물번식학회) 2011 발생공학 국제심포지엄 및 학술대회 Vol.2011 No.1

The objective of this study was to evaluate the comparison of production efficiency of oocytes and OPU (ovum pick‐up) derived embryos of Hanwoo with Holstein. The OPU session of each species (6 cows) was carried out from the Hanwoo (106 sessions) and Holstein (114 sessions) at intervals of 3 4 days (2 times per week) for 3 months. Cumulus‐oocyte‐complexes (COCs) retrieved were classified into 4 grades by the status of oocyte cytoplasm and cumulus cells. The COCs collected were matured in vitro in TCM‐199 supplemented with 10% FBS, 10 mg/ml FSH and 1 mg/ml estradiol‐ 17β in 5% CO2 and over 99% humidity for 24 h. After 24 h co‐incubation with post‐thaw sperm, the presumed zygotes were cultured in CR1aa medium with 4 mg/ml BSA for 3 days and then changed CR1aa medium with 10% of FBS for another 3 4 days. The Mean number of aspirated follicles and collected oocytes were not significantly different between Hanwoo and Holstein spacies (10.4±0.42 vs. 11.4±0.41 and 7.5±0.38 vs. 6.1±0.37 per session). But the collection rate of oocytes from aspirated follicles were significantly higher in Hanwoo (72.8%) than that in Holstein (53.6%) (p< 0.05). Furthermore, the average number of good quality oocytes (Grade I and II) was 5.9±0.28 and 4.1±0.27 (Mean±SD), and the cleavage rate and the development rate to blastocysts was significantly (p<0.05) higher in Hanwoo (40.0%) than Holstein (21.6%). The OPU derived embryos of Hanwoo were transferred 83 times into 52 recipients and then 42 calves were produced from 44 pregnancy recipients. In conclusion, the efficiency of OPU derived embryo was significantly different between Hanwoo and Holstein species. In vitro culture system for OPU derived embryo production should be optimized for industrialization and the improvement of livestock.

농장 사육되는 타조에서 나타난 다리 기형의 증례 보고

최종윤,손화영,전무형,조성환,김혜성,류시윤,박배근,이영원,윤원기 충남대학교 수의과대학 동물의과학연구소 2001 動物醫科學硏究誌 Vol.9 No.-

Two farmed young ostrich chicks were applied to pathology laboratory at Chungnam National University. Grossly, one ostrich showed rotated tibiotarsus, the other showed rolled toes. Case 1 ostrich was hypertrophy of fibualis longus and tibial cranialis tendon and gastrocnemius tendon in crus, inflammation of flexor digitorum longus. In histopathological views, myocytes of fiburalis longus were showed hypertrophy and hyperplasia. It is not found any specific feature in X-ray of the case 2 ostrich. Limb deformities were detected frequently in farmed ostrich chicks in 2- to 3 weeks old. Limb deformities were an important cause of mortality in farmed ostrich chicks during the first 10weeks after hatch. Cause of limb deformities were considered a nutrition problem.