CFRP복합재료의 적층각에 따른 가공 특성

정성택,박종남,김선진,조규재 한국공작기계학회 2002 한국공작기계학회 춘계학술대회논문집 Vol.2002 No.-

In recent days the more use of CFRP composite is in the airplane, automobile, and sport goods, etc., the more necessity of research on it in this engineering. In this research, the CFRP composite specimen are fabricated by 48 CFRP plies with 8 orientation angles, and the specimens are drilled with 3 tools. The results are analyzed with consideration of cutting force, type of tools and fabrication condition. The specimens with each drilling conditions are also investigated with SEM. The optimal drilling conditions such as drill types and cutting force with respect to the fabricating condition are studied.

양측 하악과두 골절에 대한 관혈적 정보술후 나타난 근약화와 시력장애 : 증례보고

정기훈,신용길,김태열,신재명,윤규호,전인성 대한악안면성형재건외과학회 2000 Maxillofacial Plastic Reconstructive Surgery Vol.22 No.6

The condylar fracture show high occurrence rate in the following of symphysis and angle, because it is easy to have concentration of outer pressure due to its long and narrow anatomical shape and mouth opened state when trauma is attacked. For the clinical findings, there are trismus, opening deviation, mal-occlusion and open bite The classification of condylar fracture is varied due to the location of condylar bone fragment, fracture site. There are conservative and surgical methods for treatment modalities. Because of many advantages, conservative method is widely used it has no particular limits of treatment adjustment but the cases of absolutely surgical correction indication are easily found in clinical experience. Although many methods are suggested for treatments of condylar fracture, there are no particular surgical methods for precise reduction due to difficult accessibility in high condylar neck fracture. For precise reduction of condyle, we used Nam's method. However, in Nam's method, because condyle is fixed when once it is kept off externally reduced in avascular state, so complication such as condyle resorption is pointed out as a problem. In our clinic, we obtained some knowledge by treating a patient who had muscle weakness and vision disorder after temporary airway obstruction follownig the both condylar fracure operated using Nam's method, so here we reported the case with a study of documents.

CFRP복합재료의 적층수와 드릴직경에 관한 연구

정성택,박종남,조규재 한국공작기계학회 2003 한국생산제조학회지 Vol.12 No.6

CFRP composite has a lot of merits such as mechanical characteristic, light weight, and thermal resistance. For these merits CFRP is applied to so many industrial area. In order for the composite materials to be used in the air& structures or machine elements, accurate surfaces for bearing mounting or joints must be provided, which require precise machining. In this paper, the relationship between the stack thickness and drill diameter is examined from the drilling experiment, which is the drilling of 16, 32, 48plies specimen with the φ8, φ10, φ12mm cemented carbide drill. The results are analyzed with consideration of cutting force, stack thickness and drill diameter.

적층구성이 다른 복합재의 드릴 가공에 관한 연구

정성택,박종남,조규재,심재기 한국공작기계학회 2002 한국공작기계학회 추계학술대회논문집 Vol.2002 No.-

In recent days the more use of CFRP composite is in the airplane, automobile, and sport goods , etc., the more necessity of research on it in this engineering. In this research, the CFRP composite specimen are fabricated by 48 CFRP plies with 6 stacking sequences, and the specimens are drilled with 4 tools. The results are analyzed with consideration of cutting force, type of tools and fabrication condition. The specimens with each drilling conditions are also investigated with SEM. The optimal drilling conditions such as drill types and cutting force with respect to the fabricating condition are studied.

동종 골수이식 후 만성 이식편대숙주질환과 동반되어 신증후군으로 발현된 IgA 신병증 1예

정철권,김현수,박준성,정성현,조도연,최진혁,남동기,임호영,김명성,신규태,임현이,김효철 대한조혈모세포이식학회 1999 대한조혈모세포이식학회지 Vol.4 No.2

동종 골수이식 후 발생하는 신기능부전은 원인이 다양하여 감별에 어려움이 있다. 만성 GVHD는 흉선의 기능저하에 따른 면역관용의 실패로 발생되는 자가면역현상에 의해 발생되는 것으로 알려져 있으며 드물게 신장을 침범하여 신증후군을 일으키기도 한다. CaA의 용량을 줄이거나 투약중지 후 발생한 만성 GVHD에 동반된 신증후군의 경우 조기에 신조직검사를 시행하여 감별진단하고 CsA의 용량을 증량하거나 재투약하여 좋은 치료 결과를 보일 것으로 기대된다. 저자들은 문헌고찰을 통해 동종 골수이식 후 발생된 신증후군이 유사한 임상양상을 보이며 발생기전에 만성 GVHD와 자가면역현상이 연관되어 있음을 확인하였으며 동종 골수이식 후 신증후군의 임상양상을 보이는 환자에서 병리조직학적으로 lgA 신병증을 진단하고 이러한 lgA 신병증이 발생기전에 만성 GVHD와 자가 면역현상이 연관되어 있을 가능성을 최초로 확인하였으며 CsA를 이용하여 성공적으로 치료한 경험을 하였기에 보고하는 바이다. Renal insufficiency is occasionally encountered in allogeneic bone marrow transplantation and its cause is difficult to ascertain. Chronic graft-versus-host disease (GVHD) related to thymic dysfunction is immune-mediated and involves autoreactivity of T-lymphocytes derived from donor marrow to recipient's major histocompatibility complex(MHC) minor antigens. The clinical mainifestations of chronic GVHD are similar to those of autoimmune disease but kidney involvement is rare. Few cases of nephrotic syndrome with membranous nephropathy or minimal change nephrotic syndrome have been reported to be associated with chronic GVHD in allogeneic bone marrow transplant recipient especially after cyclosporine A(CsA) withdrawal, and these cases have responded well to CsA. Therefore, it is prudent to differentiate the cause of post-transplant renal insufficiency using renal biopsy and to start CsA in a case of nephrotic syndrome associated with chronic GVHD as early as possible. We report a case who had a massive proteinuria during the post-allogeneic marrow transplantation period. The cause of nephrotic syndrome was diagnosed as IgA nephropathy by renal biopsy. The patient was successfully treated with reintroduction of CsA.

CFRP복합재료의 적층수와 드릴직경에 따른 가공 특성

정성택,박종남,조규재 한국공작기계학회 2003 한국공작기계학회 춘계학술대회논문집 Vol.2003 No.-

CFRP composite has a lot of merits such as mechanical characteristic, light weight, and thermal resistance. For these merits CFRP is applied to so many industrial area. In this paper, the relationship between the stack thickness and drill diameter is examined from the drilling experiment, which is the drilling of 16, 32, 48plies specimen with the φ8, φ10, φ12mm cemented carbide drill. The results are analyzed with consideration of cutting force, stack thickness and drill diameter.

이행성 협심증 환자에서 운동부하 심전도 검사

이정우,박형서,박용규,노상필,이유선,정승현,김보영,이재환,최시완,정진옥,성인환 충남대학교 의과대학 의학연구소 2003 충남의대잡지 Vol.30 No.1

목적 : 관상동맥의 경련에 의한 이형성 협심증환자에 있어서 운동부하 심전도 검사의 결과는 매우 다양하다. 이에 저자들은 충남대학교병원 순환기내과에서 관상동맥조영술상 이형성 협심증으로 확진된 환자를 대상으로 운동부하 심전도 검사를 시행하여 이에 대한 결과를 연구하였다. 방법 : 1995년 1월부터 2002년 3월까지 흉통을 주소로 충남대학교병원 순환기 내과에 입원하여 관상동맥조영술을 시행하여 관상동맥의 내경이 50% 미만의 협착이 있고, 에르고노빈(ergonovine) 유발검사도 이형성 협심증으로 진단을 받은 233명중 운동부하 심전도 검사를 시행 받은 183명의 환자를 연구 대상으로 하였다. 운동부하 심전도 검사 결과의 판독시 발생할 수 있는 오류를 줄이기 위해서 운동부하 심전도 검사를 시행하기전 심전도상 ST분절의 상승(5예)이나 하강(8예)이 있는 경우 EH한 T파의 역위(19예)가 있는 32명의 환자를 제외한 총 151명의 환자를 대상으로 하였다. 운동부하는 Marquette사의 case 15 답차를 이용하였고, Bruce protocol에 따라 증상이 나타날 때까지 최대로 실시하였으며 각 stage 및 운동후의 혈압을 측정하고 12 유도 심전도를 기록하였다. 결과 : 1) 임상적 특성 - 내원시 임상 상은 안정형 협심증이 39예(25.8%), 불안정형 협심증이 103예(68.2%), 심근경색증이 9예(6.0%)이었다. 운동부하 심전도 검사 결과 양성 군과 음성군간에 있어서 당뇨병, 고혈압, 비만도, 총 혈청콜레스테롤치, 현재의 흡연 여부, 병력상 운동시 흉통의 유무, 내원시 임상적 진단, 협착의 정도, 연축의 수 등을 조사하였는 바 어떠한 인자들도 유의한 차이를 발견할 수 없었다. 2) 운동부하 심전도 검사 - 운동부하 심전도 검사를 시행 받은 151명의 환자중 음성인 경우는 134예(88.8%)이었고, 양성인 경우는 17예(11.2%)이었다. 양성 소견을 보인 환자들중 ST 분절의 상승이 4예(2.6%), ST 분절의 하강이 13예(8.6%)이었다. 3) 관상동맥조영술 - 관상동맥조영술상에서 혈관 경력 위치는 우관상동맥이 70예(46.1%), 좌전하동맥이 44예(28.9%), 좌회선동맥이 17예(11.2%)의 순으로 나타났다. 운동부하 심전도 검사상 ST 분절의 상승이 있었던 예중 Ⅱ, Ⅲ, aVF에서 ST 분절의 상승이 있었던 1예는 관상 동맥조영술상 우관상동맥에서 경련이 발생하였고, V2-V4에서 ST 분절의 상승이 있었던 2예중 관상동맥조영술상에도 좌전하행동맥에서 경련이 나타난 예는 1예이었으며 다른 1예는 좌회선동맥에서 경련이 나타났고, V5-V6에서 ST 분절의 상승이 있었던 1예는 관상동맥조영술상에도 좌회선동맥에서 경련이 나타났다. 운동부하 심전도 검사상 V5 또는 V6에서 ST 분절의 하강이 있엇던 13예중 6예(46.1%)는 관상동맥조영술상 우관상동맥에서 경련이 발생하였고, 3예(23.1%)는 좌전하행동맥에서, 1예(7.7%)는 좌회선동맥에서, 나머지 3예(23.1%)는 2개의 혈관이나 기타 분지에서 경련이 발생하였다. 결론 : 1) 이형성 협심증 환자는 운동부하 심전도 검사에서 11.2%의 양성소견을 보였다. 이중 ST 분절의 상승은 2.6%이었고, ST 분절의 하강은 8.6%이었다. 2) 이형성 환자중 운동부하 심전도 검사를 실시하여 음성을 보이는 경우 다혈관 관상동맥질환이기 보다는 이형성 협심증일 가능성이 더 높다고 예측할 수 있을 것으로 생각된다. 3) 이형성 협심증 환자중 운동부하 심전도 검사를 실시하여 ST 분절의 상승을 보이는 경우 다혈관 관상동맥질환이기 보다는 이형성 협심증일 가능성이 더 높다고 예측할 수 있을 것으로 생각된다. 4) 운동부하 심전도 검사 결과에 대한 당뇨병, 고혈압, 비만도, 총 혈청콜레스테롤치, 현재의 흡연여부, 병력상 운동시 흉통의 유무, 내원시 임상적 진단, 협착의 정도 등 어떠한 인자들도 3그룹(ST 분절의 상승, ST 분절의 하강, 음성)간에 유의한 차이를 발견할 수 없었다. 5) ST 분절의 상승 부위와 관상동맥조영술상 관상동맥의 연축이 일어나는 혈관과의 상관관계는 매우 높았다. No reports in the literature describe the results of exercise testings in a large number of patients with pure variant angina(coronary stenosis <50%) in Korea. In this report, We present the results of treadmil exercise testing in 151 patients with variant angina. 151 patients with angiographically proven coronary artery spasm underwent a treadmil exercise test. The clinical characteristics of variant angina patients classified according to ST-segment response to exercise were analyzed. Of 151 patients underwent a treadmil exercise test, negative result was seen in 134 patients(88.8%) and positive result was in 17 patients(11.2%). Of 17 patients saw positive result, exercise-induced ST segment elevation was present in 4 patients(2.6%) and ST segment depression was seen in 13 patients(8.6%). There was not a significant relationship between the ST segment response to exercise and the clinical variables(diabetes, hypertension, obesity, total cholesterol, current smoking, effort angina, clinical diagnosis, and degree of stenosis) assessed. Of 4 patients with ST segment elevation in treadmil exercise test, 1 patient with ST segment elevation in Ⅰ,Ⅲ,aVF had spasm in right coronary artery(100%) on coronary angiography, of 2 patients in V2-V4 had spasm in left anterior descending coronary artery in 1 patient(50%) and 1 patient in V5-V6 had spasm in left circumflex artery(100%). Positive treadmil exercise test was present in 11.2% of variant angina patient. If we have negative treadmil exercise result in patients with clinical manifestation of unstable angina at admission, we may have a suspicion of variant angina rather than multi-vessel disease. If we have exercise-induced ST segment elevation in patients with clinical manifestation of unstable angina at admission, we have a suspicion of variant angina rather than multi-vessel disease. Our result suggests that the correlation between the site of the ST segment elevation and the artery involved is quite good.

암모니아 공정에서 CO₂ 고정의 최적화

서성규,이정섭,송준석 國立麗水大學校 環境問題硏究所 2004 環境硏究論文集 Vol.6 No.-

This study was investigated the effects of various system parameters on the absorption of carbon dioxide into absorption solution. An aqueous potassium carbonate solution was used as a chemical absorbent in order to figure out the effect of chemical reaction. For this purpose, the chemical analysis of potassium carbonate solution was performed. The changes of pressure, temperature, K₂CO₃solution flow/feed gas ratio and solution concentration in the absorber and the changes of pressure and temperature in the stripper were also analyzed. The analysis result shows that K₂CO₃ concentration in potassium carbonate solution was 99.6%. The optimum pressure was found to be 27.0㎏/㎠ and the optimum temperature was to be 68℃, the optimum concentration of potassium carbonate solution was to be 26.0wt% in the absorber. The CO₂ leakage decreased with the increment of the K₂CO₃ solution flow/feed gas ratio. But the H₂ leakage in the CO₂ product increased at or above the K₂CO₃ solution flow/feed gas ratio of 1.10. This H₂ leakage induced by the loss of ammonia production. The effects of the changes of the operation condition of the CO₂ stripper to the K₂CO₃ conversion are as follows. The K₂CO₃ conversion decreased as the pressure decreased. The K₂CO₃ conversion increased as the temperature increased. However, increasing the temperature without decreasing the pressure did not bring positive effect. The optimum pressure was found to be 0.45㎏/㎠.

처분장근처에서 침식에 의한 Sr 화학종의 평형

조윤정,김성현,이인화,김시욱,고문주,박성규,이범규 조선대학교 환경공해연구소 2000 環境公害硏究 Vol.16 No.1

Leaching and adsorption equilibria of Sr Chemical Species from the near field of a repository has been studied in solidified cement with Fe and oxidized Fe. The absorption percent, Ads %, and distribution coefficient, K_(d) were calculated using equilibrium concentration to predict the extent of leaching and adsorption. In the mixed aqueous solutions the Ads % increase as Cement(C)/Water(W) ratios increase and K_(d) was decreased for Sr. These behaviors were discussed by adsorption and equilibrium of spiked ions. Oxides Fe promoted the adsorption of spiked ions, but pure Fe had no effect. E_(h) values were also estimated and discussed to elucidate oxidation-reduction environment of experimental system.

선택중심 교육과정의 운영을 고려한 고등학교 소요교실 산정에 관한 연구

김정규,정주성 대한건축학회 2004 대한건축학회논문집 Vol.20 No.1

This study aims to estimate the number of classrooms to operate optional subject curriculum in high school. The study consists in two parts. First, it analyzes the national level curriculum, the province guidances, and operating programs studied in several high schools to investigate factors affecting the number of classrooms. Secondly, it induces an arithmetic expression to estimate the number of classrooms to operate optional subject curriculum, and verifies the arithmetic expression through timetable simulation. The result of this study will be useful to estimate the scale of high school as the architectural space programing tool.