인코넬 690 합금의 크리프거동

황경충,윤종호,최재하,김성청 한국공작기계학회 2002 한국생산제조학회지 Vol.11 No.4

Inconel 690 alloy has widely been used in power plant and high temperature facilities because it has high thermal resistance and toughness. But, we have little design data about the creep behaviors of the alloy. Therefore, in this study, an apparatus has been designed and built for conduction creep tests under constant load conditions. A series of creep tests on Inconel 690 alloy have been performed to get the basic design data and life prediction of inconel products and we have gotten the following results. First, the stress exponents decrease as the test temperatures increase. Secondly, the creep activation energy gradually decreases as the stresses becomes bigger. Thirdly, the constant of Larson-Moller parameters on this alloy is estimated about 10. And last, the fractographs at the creep rupture show both the ductile and the brittle fracture according to the creep conditions.

부재료 첨가에 따른 갓김치의 항산화성

최영숙,황정희,김재이,전영수,최홍식 부산대학교 김치연구소 2000 김치의 과학과 기술 Vol.6 No.-

Antioxidative activities (AA) of mustard leaf kimchi (MLK) by the addition of optional ingredients among selected minor materials were studied. In order to determine AA of MLK with different spices, the model systems of ground cooked beef with green onion, garlic, and red pepper powder were prepared and stored for 4 weeks at 4℃. AA of red pepper added group was stronger than those of others. AA of red MLK was relatively higher than that of (green) MLK. For the enhancement of AA of MLK, another model systems were prepared with the selected antioxidative optional ingredients, which were bonnet bellflower root, leek, burdock, sea tangle, sea mustard, seastaghorn at the level of 2% or 4%. The extracts of water, 75% methanol and hexane of MLK, bonnet bellflower root added MLK, and seastaghorn added MLK had a considerable AA with the inhibition of peroxide formation during the autioxidation of linoleic acid mixtures in aqueous model systems at 37℃. Therefore, AA was more effective in MLK containing specific optional ingredients than that of MLK alone significantly.

절삭공구 팁의 TiCN코팅 특성

황경층,윤종호,최재하,김성청 충북대학교 산업과학기술연구소 2002 산업과학기술연구 논문집 Vol.16 No.2

As the machine tool industry progresses, the performance of cutting tools also needs to be of good quality and specialized. If the existing metal cutting tool tip is coated properly, its life would be longer and the machining of a difficult-to-cut material also could be possible. For the development of the high quality cutting tool, the applicabilities of TiCN coating deposited by PVD on the cutting insert were experimentally investigated. The various analyses such as SEM micrograph, XRD pattern, AFM surface morphology, and hardness were performed to cross-check the possibility and availability of TiCN coated tool in the field.

순환기 내과로 자문의뢰된 환자의 임상상

황진용,최지용,손상균,조용근,채성철,전재은,박의현 慶北大學校 醫科大學 1996 慶北醫大誌 Vol.37 No.4

목적 : 순환기내과 영역은 많은 과로부터 자문의뢰를 받는 영역으로 알려져 있다. 특히 최근 우리나라의 순환기질환의 유형이 변화되고 입원환자가 고령화되면서 동반된 심질환의 유병율도 증가하고있다. 이에 저자들은 타과로 입원하여 순환기내과로 자문의뢰되는 환자의 임상상과 3차병원인 경북대학교병원에서의 순환기내과자문의 유용성 등을 평가하여 향후 순환기질병에 대한 협의진료에 도움을 주고자 본 연구를 시행하였다. 방법 : 1995년 3월부터 순환기내과로 공식자문의뢰된 첫 100명을 대상으로 전향적으로 연령, 의뢰이유, 최종진단명, 수술과의 관련성 여부, 순환기내과의 최종조치, 타과의 순응도 등을 조사하였다. 결과 : 1) 자문을 의뢰한 환자는 평균 58±16(15-89, 중앙치 61)세였고 60세이상의 환자가 57%로 고령의 환자가 많았다. 2) 내과계열 25%, 외과계열 75%로 외과계열의 자문이 많았고 일반외과가 26%로 가장 많았고 내과의 다른 분과가 12%, 신경외과 12%, 정형외과 11%, 흉부외과 11%, 신경과 11% 등의 순이었다. 외과계열중 수술을 시행한 경우는 58례로 이중 응급수술이 13례였다. 술전 위험도 평가를 위한 자문이 38례에서 있었는데 순환기적인 문제로 수술을 받지 못한 경우는 2례(1례는 허혈성 심질환, 1례는 심낭질환)이었다. 이때 응급수술을 제외한 입원일과 술전 자문일파의 간격은 평균 3±7일(입원일-42일)이고 술전 자문일과 수술일과의 간격은 평균 6±4일(1-16일)이었다. 3) 타과의 의뢰이유는 심전도 이상이 36례, 높게 측정된 혈압이 20례, 순환기질환의 과거력 17례, 환자의 증상 때문인 경우가 10례였고 심전도의 이상중에는 부정맥이 18례, 이상 Q파 6례, ST절 이상이 5례, 각차단이 3례의 순이었다. 순환기과거력 중에는 허혈성 심질환이 6례, 현재 혈압은 정상이나 고혈압의 과거력이 있는 경우가 4례 순이었고 환자의 증상은 흉통 6례, 호흡곤란이 3례, 기절이 1례였다. 4) 자문후 최종진단이 가능했던 91례를 진단별(총 97 진단명)로 나누어 보면 고혈압이 28례, 부정맥이 16례, 허혈성 심질환이 14례, 판막질환이 11례, 순환기질환이 아닌경우가 19래였다. 이들중 추적진료가 필요하다고 응답한 경우가 57례였으나 순환기내과 외래에 1번이상 추적진료한 경우는 32례(56%)로 환자의 순응도는 낮았다. 결론 : 순환기내과의 자문의뢰는 고령자에게 많았고 수술과 관련된 경우가 많았으며 심전도의 이상이 의뢰이유로 가장 많았으며 진단별로는 고혈압과 부정맥이 가장 많았다. 그리고 순환기적인문제로 수술을 받지 못한 경우는 드물었고 자문후 지속적인 추적진료를 위해 환자의 교육이 필요하겠다. Objective : Clinical characteristics of the patients with cardiovascular diseases in the general hospital have been changed and prevalance of co-existing cardiovascular disease in the patients who were admitted for non-cardiac diseases has been increased remarkably as the proportion of elderly patients increased rapidly in Korea. We evaluated clinical features of the patients consulted for cardiological evaluation and effectiveness of the consultation in the setting of tertiary general hospital, Kyungpook University Hospital. Method : One hundred patients were studied between January 1995 and January 1996. They were evaluated for the reason of consultation, final diagnosis, final recommendation from cardiologists and its impact on the management of the patients, and compliance of the consulting departments. Results : 1) The ages ranged between 15 and 89 (mean 58±16, median 61) years, 57 patients were male and 43 female. Fifty seven patients were older than 60 years. 2) Consultations from surgical parts were 75 patients. Consultation from general surgery was most frequent (26%), followed by other divisions of internal medicine (12%), neurosurgery (12%) and orthopedic surgery (11%), chest surgery (11%), neurology (11%), obstetrics and gynecology (8%), urology (4%), ophthalmology (2%), dermatology (2%), ENT (1%). Among 75 patients from surgical parts, operation was done on 58 patients, including 13 emergency cases. Preoperative cardiac risk evaluation was the reason of consultation in thirty eight patients, of which operation could not be done in only 2 patients (one had severe ischemic heart disease, the other large pericardial disease). Interval between consultation day and operation day was 6±4 days (1-6 days). 3) Reasons for cardiac consultation were electrocardiographic (ECG) abnormalities in 36 patients, high blood pressure in 20 patients, previous cardiovascular diseases in 17 patients, symptoms of the patients in 10 patients. Among EGG abnormalities, arrhythmias was the reason in 18 patients, abnormal Q waves in 6 patients, ST-T segment abnormalities in 5 patients, bundle branch block in 3 patients. Among previous cardiovascular disease, presence of ischemic heart disease was the reason in 6 patients, previous hypertension in 4 patients. Chest pain was the reason of the consultation in 6 patients, dyspnea in 3 patients, syncope in 1 patient. 4) Definite diagnoses could be made in 91 patients with 96 diagnoses which were hypertension and its complications in 28, arrhythmia with underlying disease in 16, ischemic heart disease in 14. valvular heart disease in 11, non-cardiovascular disease in 19. Cardiological follow up was recommended in 57 patients. However, 25 patients (44%) were lost to follow-up. Conclusion : Cardiological consultation was frequent in the elderly patients. Most frequent reason for consultation was EGG abnormalities. Hypertension or arrhythmia was most common final diagnosis. Inoperability due to cardiovascular problems were rare.

인코넬 690 합금의 절삭성에 관한 연구

황경충,윤종호,최재하,김성청 한국공작기계학회 2002 한국생산제조학회지 Vol.11 No.2

In domestic industry, there is no manufacturers specialized in the production of cutting tools for the difficult cutting materials. Then, we have few data about them. In this study, the gear driving high speed lathe on which is mounted by a tool dynamometer and high speed CCTV were used to measure the various machining characteristics. Relations among the cutting speed, feed rate per revolution, cutting depth, cutting forces and surface roughness were graphically analyzed under 64 cutting conditions. The process of chip, i.e., generation, development and falling-off also were visualized for the characterization of chip shapes of the difficult-to-cut materials using the CCTV.

體育特技者의 肺機能과 運動後 恢復期의 血液가스의 變化

崔圭澤,朴載植,黃樹寬,朱永恩 慶北大學校 1985 論文集 Vol.39 No.-

The pulmonary function and changes of blood gas tensions and pH in the athletes have been reported but are fragmentary as to require more complete studies including all the pulmonary parameters and blood gas tensions especially at the early part of 20 years of age. This study was aimed to elucidate the pulmonary function at the rest and the changes of venous blood gas tension and pH after the exercise in the athletes of physical education students. The subjects chosen for this study were 15 athletes of physical education students (special group) of 21-25 years of age. The athletes had at least four years of exercise careers, and were compared with 12 non-athletes of physical education students (general group) who had not been subjected to any form of rigorous training program. All the subject were directed to perform running on the treadmill for three minutes under the condition of 15% grade and 5 MPH. The venous blood samples were taken at the rest as well as at 0, 5, 10 and 20 minutes after the exercise to check the changes of Pco_2, Po_2 and pH during the recovery period. The venous blood Pco_2, Po_2 and pH were determined using the Model 175 Automatic Blood Gas Analyzer by Corning Co., and the pulmonary function using the computerized spirometer. The results obtained were compared with the general group and summarized as follows: The special group exhibited higher values of the pulmonary function except FVC compared with the general group, and particularly FEV_0·5% and FEV_1% were significantly different. The venous Po_2 was decreased immediately after the exercise, but increased during the recovery period. The special group generally showed higher oxygen partial pressure than the general group. The venous Pco_2 in contrast to the oxygen increased immediately after the exercise, but decreased during the recovery period. The special group showed lower carbon dioxide partial pressure. Blood pH was significantly decreased from the resting value after the exercise and returned to the resting value at 20 minutes. In the special group, however, the change of pH was less than in the general group.

수술로 절제된 간의 국소 결절성 증식의 임상적 특징

황남철,최문석,이준혁,고광철,백승운,유병철,이종철,이광웅,조재원,박철근 대한간학회 2004 Clinical and Molecular Hepatology(대한간학회지) Vol.10 No.2

목적: 간의 국소 결정성 과형성은 일반적으로 특별한 치료가 필요 없는 양성 종양이다. 그러나 드물지만 합병증이 발생한 경우와 진단이 불확실한 경우에는 수술을 시행하게 된다. 이에 저자들은 간절제술을 시행한 국소 결절성 과형성의 임상적, 영상학적 특징들을 알아보고자 하였다. 대상과 방법: 1995년부터 2003년까지 수술을 시행하여 조직을 확인한 국소 결절성 과형성 환자 10명을 대상으로 연령, 성별, 실험실 검사 및 영상 소견과 조직 소견을 분석하였다. 결과: 연령의 중앙값은 37.5세, 남녀 비는 1.5:1이었다. 5예에서는 간세포선종이나 간세포암종을 감별할 수 없어서 수술을 시행하였으며, 수술 후 우연히 진단된 예는 4예이었다. 간세포암종의 위험 인자를 가지고 있었던 예는 4예(B형 간염 바이러스 보유자 3예, 간경변 2예)이었다. CT검사가 시행되었던 6예 중 5예는 동맥기에서 조영 증강을 보였고 문맥기 및 지연기로 감에 따라 주변과 동일(4예)한 또는 감소(2예)되는 양상을 보여 간세포암종과의 감별이 어려웠다. 크기는 3.2±2.2㎝이었으며 위치는 간우엽의 후하구역(S6)에 가장 많았다(30.0%). 4예에서 수술 전 침생검을 시행하였으나 고분화 간세포암종이나 간세포선종과의 감별이 어려웠다. 결론: 임상상, 영상검사 및 간침생검으로도 간세포암종이나 간세포선종과의 감별이 어려운 경우 수술을 시행하였으며 수술 전에는 발견하지 못하였지만 다른 질환으로 인한 수술시 우연히 발견된 경우도 있어 국소 결절성 과형성의 수술 전 진단이 어려운 경우가 적지 않음을 알 수 있었다. Background/Aims: Focal nodular hyperplasia (FNH) is a benign hepatic tumor with few serious complications and no malignant transformation. However, differential diagnosis between FNH and other liver tumors, especially hepatocellular carcinoma, is often difficult. Methods: Clinical features of surgically resected FNH were reviewed. From January, 1995 to February, 2003, 10 patients with surgically resected FNH were enrolled. Their age, sex, results of laboratory examination, imaging studies and pathologic findings were evaluated. Results: Median age was 37.5 years and sex ratio (male:female) was 1.5:1. In 5 cases, resection to exclude hepatic adenoma or HCC was performed. Four cases were diagnosed incidentally after surgery. Four patients had risk factors for HCC, such as hepatitis B virus infection, liver cirrhosis or both. The size of FNH was 3.2 2.2 cm. The most common site of the tumor was segment 6 (30.0%). Differential diagnosis with HCC was difficult in 5 of six cases in whom CT was performed. Although needle biopsies were performed preoperatively in 4 cases, it was difficult to distinguish FNH from hepatic adenoma or HCC. Conclusions: FNH was resected due to uncertainty of diagnosis, or incidentally during hepatectomy in patients with other liver disease. In the former, differential diagnosis with hepatic adenoma or HCC was a major problem despite extensive work-up including dynamic CT or biopsy. (Korean J Hepatol 2004;10:135-141)

Starter 및 멸치액젓 첨가가 김치양념 및 겉절이 김치의 품질에 미치는 영향

최택권,박소희,유진현,임호수,조재선,황성연 한국식생활문화학회 2003 韓國食生活文化學會誌 Vol.18 No.2

양념에 Leu. mesenteroides, Lac plantarum의 젖산균과 멸치액젓 첨가가 김치 양념의 대장균군 제어, 속성촉진여부 및 관능적 특성에 미치는 영향을 조사하였다. Leu. mesenteroides과 젓갈을 첨가한 경우 초기 숙성이 촉진되나 후기 산패는 완만하였으며 Lac. plantarum의 첨가시에는 초기 숙성에는 큰 차이가 없고 후기 산패가 현저하게 진행되었다. 대장균군은 산도 0.80% 이상에서 사멸되었는데 leu. mesenteroides의 경우가 숙성이 촉진되어 보다 신속히 사멸시켰다. 총균수와 젖산균수는 초기에 starter 첨가구는 10^6CFU/mL 정도인데 반해서 starter를 첨가하지 않은 않은 처리구에서 총균수는 10^6CFU/mL , 젖산균수가 10^4CFU/mL 이었고 숙성 후에는 첨가균이 높은 수준을 유지하였다. 하지만 대체적으로 스타터의 첨가가 숙성 및 대장균에 크게 영향을 주지 못하는 경향으로 동일하게 나왔다. 관능적 특성에서는 Leu. mesenteroides 첨가구가 Lac. plantarum의 경우보다 우수하였다. 한편, 시판 겉절이 김치는 산도가 0.09~0.18%, ph 5.46~5.89, 총균수 2.2×10^6~3.1×10^7CFU/mL, 젖산균수는 2.1×10^4~6.6×10^5CFU/mL, 대장균수는 1.8×10^4~7.1×10^5CFU/mL, 염분 1.89%~2.51%으로 스타터 첨가 겉절이에 비해 ph와 염도를 제외한 품질 특성에서 전반적으로 낮은 값을 나타냈다. This study was performed in order to investigate the effect of Leuconostoc mesenteroides, Lactobacillus plantarum and salt fermented anchovy extracts on Kimchi sauce. The sauce was fermented more rapidly by addition of Leu. mesenteroids or salt fermented anchovy extracts on the early fermentation stage than the control, but it was fermented slowly on the late fermentation stage. When L. plantarum was added to the Kimchi on the early fermentation stage, the acidity of Kimchi didn't show a significant difference from the control, but acidity was remarkably increased on the late stage. Coliform group was disappeared when acidity of sauce was higher than 0.8% during fermentation. It was controlled by Leu. mesenteroides but not by L. plantarum. Total count and lactic acid bacterial count of the sauces with starter were 6.30×10^6~1.0×10^7 CFU/mL and 1.04~2.04×10^6 CFU/mL, respectively, but those of the control sauce were 10^6 CFU/mL and 10^4 CFU/mL, respectively. Those count of the sauce with starter were higher than those of the control sauce on the later stage of fermentation. Organoleptic quality of the sauce with Leu. mesenteroides was superior to that with L. plantarum.

N₂분위기에서 Solder 접합부의 젖음성 및 결함특성에 관한 연구

최명기,황선효,이창배,정재필,서창제 大田産業大學校 2001 한밭대학교 논문집 Vol.18 No.-

본 실험을 통하여 대기와 N_2분위기에서의 젖음력과 솔더 접합부의 결함특성에 대하여 연구 검토하였다. 모든 시편 조건에서 질소분위기에서의 젖음성이 대기 중에서 젖음성 보다 좋아졌다. 또한 N_2유량이 증가함으로서 젖음 시간은 짧아지고, 젖음력은 증가하였다. N_2분위기에서 브리지(Bridge)발생률이 25∼76%정도로 현저히 감소하였다. N_2분위기에서는 젖음력의 향상으로 솔더 접합부가 안정되었으며 결함 발생률도 현저하게 감소되는 것을 확인할 수 있었다. This study was prepared to find out wettability and properties of defects on solder joints in N_2 conditions. The wettability of solder joints in N_2 condition was better than that in atmosphere condition, and when the flow rate of N_2 was increased, it is found that the wetting time got a little bit short and the wetting force got stronger as time passed. Also the rate of bridge defects was specially decreased in N_2 conditions, showing the decreasing ratio of 25∼76%. The solder joints were stabilized and the rate of defects was decreased by cause to increasement of wetting force in N_2 conditions.

폐전선 피복재 건류탄을 이용한 제강분진처리를 위한 기초연구

황용길,이상화,이성룡,정석수,최재신,조충형 東亞大學校 1995 東亞論叢 Vol.32 No.-

Distilled carbon from waste electric wire coated by vinyl is used to recover valuable metal such zinc, lead and iron in dust. Pemeability and compressive tests are who done to present basic data on extraction of zinc in dust. Experimental results obtained from sintering property of steelmaking dust, distilled carbon from waste electric wire coated by vinyl and waste pulp sludge mixture briquet at various sintering temperature are as followings; Permeability is increased as increasing distilled carbon and pulp amount at higher temperature than room temperature condition. Compressive strength at room temperature is increased as increasing distilled carbon and decreasing waste pulp amount, but decreased as increasing temperature and waste pulp amount. Weight Loss reaction experiment is increased a increasing distilled carbon and waste pulp amount. ZnO and Fe₃O₄ are obtained from sample containing ZnO, Fe₂O₃ and ZnO at 800℃. Permeability test at 500℃ and 800℃ did not well, because of 13.3% CaO in distilled carbon. Sample because semmi melted state at 1000℃. Distilled carbon obtained from waste electric wire showed effect of reduction and flux material.