析出型 高强度 經合金材料에 있어 過時效에 대한 延伸率의 영향

李承珥,李俊熹 成均館大學校 1977 論文集 Vol.24 No.-

Al-9.30% Zn-1.19Mg alloys with a high Zinc content are added with Cu and Zr. (0.2 % respectively). Using Vickershardness tester, we investigated the ageing characteristics of these alloys under various temperatures of heat treatment (150℃, 170℃ and 190℃). We studied the strength and elongation using Instron at the same hardness of the primary Zone and Over-ageing Zone in the age hardness curve. We used the 1mm/min cross-head speed. We obtained an excellent material with tensile strength over 40 kg/㎟ and elongation more than 16 %. Both age hardening velocity and maximum hardness value turned out to be high.

A1系 合金의 加工熱處理와 腐蝕特性에 관한 硏究

李承珥 成均館大學校 科學技術硏究所 1985 論文集 Vol.36 No.1

Effect of thermomechanical treatment on the intergranular corrosion and stress corrosion cracking of an AI-Zn-Mg alloy have been studied. The results obtained from this experiment are as follows. 1. In the case of thermomechanical treatment; The stress corrosion cracking resistance was increased with an increase of final aging temperature. 2. The stress corrosion cracking resistance of the thermomechanical treatment specimens which are treated finally at 150℃ was enhanced with the increase of cold work, and the intergranular corrosion resistance was also increased with the increase of cold work. 3. Though the final aging temperature is high, as well as low, the effect of thermomechanical treatments on the stress corrosion cracking resistance is in line with that of the inter-granular corrosion resistance.

무우 모자이크 병에 對한 硏究

愼承縡 진주산업대학교 1969 論文集 Vol.3 No.-

有翅진딧물의 飛來가 무우 Mosaic 病의 傳染에 支配的인 因子라는 事實로 有翅진딧물의 飛來時期를 考慮하여 무우 播種期를 變更함으로써 또 무우 生育時期別 發病率을 調査함으로써 무우 Mosaic病을 減免할 수 있을 것으로 思料되어 播種時期別 罹病率과 生育時期別 發病率을 調査하여 무우의 安全한 栽培를 爲한 播種適期와 防除適期를 알고저 本實驗을 行하여 그 結果를 報告한다. 1. 무우 Mosaic病 發病最盛期는 播種後 32∼35日後 라는 것을 알 수 있다. 2. 播種期가 빠를 수록 罹病率이 높고 늦을 수록 罹病率이 낮다는 것을 알 수 있었다. Whole farmers cultivating radish and cruciferous crops throughout Korea and other nations in the world are badly suffering from the damages of radish mosaic virus disease. The radish is a very important food Korean people in autumn and winter. No one know when this disease occure at the first in Korea since there are no reports on this disease. Now-a-days, writer noticed a great mosaic disease occurance in Chinju district, Kyung nam province, Korea. In the last year, 1967, the damages of this radish disease in this district amounts to almost thirty to seventy percent even though there are cultivated various kind of varieties of radish, susceptible or resistant, and the conditions of cultivations are very different from each other, namely, whether they are sown in early times or sown in late times, or catch cropped or not. Author thought that this disease occurence depends upon winged aphids density. In order to develope preventative measure against this disease, this experiment was carried out to find out the most considerable sowing time to avoid the attaction from aphids and to find out the radish mosaic disease appearence percentage according to each growing time. The results obtained from this experiment are as follows. 1. The percentage of radish mosaic disease occurence occured severely thirty two to twenty eight to thirty five days after sowing date even though the seeding date was different each other. 2. Early sowing shows very high percentages of this disease while late shows low percentages.

Al-Mg系合金의 低溫靭性에 관한 硏究

李承珥 成均館大學校 1982 論文集 Vol.32 No.-

All alloys have recently been used as cryogenic structural materials. The purpose of the present paper is to study tensile properties and behavior at impact test of Al-Mg alloys between room temperature and -196℃. In Al-Mg alloys, the effects of Mg cntents on tensile strength were investigated and variations of toughness with Mg contents and temperatures were investigated by instrumented charpy impact test. The results are as follows: 1) As the temperature is decreased, the absorbed energy is decreased slightly from room temperature to-76℃ and decreased rapidly below-76℃ 2) With increasing the Mg contents, the tensile strength is increased and the absorbed energy is decreased. 3) With increasing the Mg contents and decreasing the temperature, the fracture load is slightly increased and deflection is decreased. 4) Al-Mg alloys showed a reduction of notch toughness at low temperature.

작업자 요통안전대책에 관한 연구

허성관,임승환,배극윤 대구대학교 과학기술연구소 1998 科學技術硏究 Vol.5 No.1

The purpose of a study is to obtain accurate information about the low-back pain safety at tasks of the worker. The study investigated formerly studies and ergonomic design for low-back pain safety and general prevention condition. That will based paper for a low-back pain safety of the calamity at the Korea. The results show that there are significant characteristics and trends on a low-back pain accidents. These findings identified in this study can be used to manage the a low-back pain prevention efforts.

정량적관상동맥조영술의 정확도 및 재현도

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

목적 : 정량적관상동맥조영술이 최근 널리 보급되고 있지만 국내외를 막론하고 이의 정확도 및 재현도에 관한 연구가 불충분하여 본 연구를 하였다. 대상 및 방법 : 110명의 환자에서 미국 General Electric사의 Advantx L/C/LP 디지탈혈관찰영기와 미국 USCI사의 좌관상동맥용 Judkins형의 Pro-Flo XT^(TM) 6F 도자를 이용하여 좌관상동맥조영술을 같은 각도에서 3회 실시하고 도자의 외경을 일본 Mitutoyo사의 정밀도 0.01㎜의 micrometer로 측정한 후 측정된 도자의 실제 직경과 정량적관상동맥조영술로 측정된 관상동맥의 직경을 비교하였다. 결 과 : USCI® Pro-Flo XT^(TM) 6F 좌관상동맥용 도자의 실제 외경은 1.91±0.03㎜이었고 정량적관상동맥조영술로 측정 한 도자의 외경은 1.94±0.11㎜이었다. 도자를 5.7F로 calibration했을 매 도자의 외경은 1.87±0.12㎜이었다. 세번 다 다른 화상에서 측정한 경우 근위부관상동맥 직경의 차이는 0.02±0.12㎜이었고 같은 화상에서 3회 측정하였던 경우에는 0.11±0.01㎜이었다. 결론 : 정량적관상동맥조영술의 정확도 및 재현도는 사용에 적합한 정도이나 적지 않은 문제점에 대한 보완이 필요하다고 생각된다. During quantitaive coronary angiography(QCA), contrast filled catheter is usually used as a scaling device. However the real diamerer of catheter is almost always smaller than the listed diameter. We measured the real diameter of catheters with precision micrometer(Mitutoyo® Japan). After caliberating the catheter as listed French size and diameter, we did QCA at the same tube position of the diameters of catheter and proximal left coronary artery. All measurements were done 3 times consecutively. The mean real diameter of USCI® Pro-Flo XT^(TM) 6 F left Judkin catheter was 1.91±0.03 ㎜. The mean QCA diamter of the same catheter was 1.94±0.11 ㎜. When we calibrated catheter as 1.91 ㎜. the mean QCA diameter was 1.87±0.12 ㎜. The mean differences of the diameters of the proximal left coronary artery were 0.20±0.12 ㎜ when the measurements were done in three different frames. When the measurements were done in the same frmae, the mean difference decreased to 0.11±0.01 ㎜. We conclude that the precision and reproducibility of QCA are within reasonable range, but more refimement is needed.

혈관내피세포-U937세포의 부착에 미치는 Eicosapentaenoic Acid의 효과

김은지,전재은,임현주,차성철,정의룡,조용근,조용근 경북대학교 병원 1998 경북대학교병원의학연구소논문집 Vol.2 No.1

연구배경: 역학적연구에서 어류의 섭취가 많은 집단에서 관상동맥질환의 빈도가 낮은 것이 보고되었고, 이것은 어류에 많이 함유된 불포화지방산(polyunsaturated fatty acid) 특히 eicosapentaenoic acid 때문으로 생각되어지고 있다. 본 연구에서는 동맥경화증 발생의 초기단계로 여겨지는 단핵구와 혈관내피세포 사이의 adhesion에 미치는 다불포화지방산의 영향을 in vitro system에서 관찰하고자 하였다. 방 법: 제대정맥에서 얻은 혈관내피세포를 배양하여 96 well에 옮기고 25, 50, 100, 200 ㎛ 농도의 eicosapentaenoic acid(EPA)를 6시간 동안 처리한 U937세포를 부착시켜 adhesion assay를 시행하였다. 혈관내피세포를 자극하기 위해서는 lipopolysaccharide(LPS)를 well당 100 ng씩을 투여하였다. 음성대조군으로는 LPS로 자극하지 않은 혈관내피세포에 EPA처리를 하지 않은 U937세포로 adhesion assay한 성적을 사용했고, 양성대조군으로는 LPS로 자극한 혈관내피세포에 EPA처리를 하지 않은 U937세포로 adhesion assay한 성적을 사용했다. 그리고 EPA(3.3 mM)을 5㎛ CuSO4 및 300 ㎛ asscorbic acid와 혼합하여 섭씨 37도에서 16시간 두어 산화-EPA를 만들어 같은 실험을 반복하였다. 결 과: U937세포에 25, 50, 100, 200 ㎛의 EPA로 6시간 처리하였을 때 U937세포의 생존율은 99% 이상이었다. 혈관내피세포를 LPS로 자극했을 때 adhesion assay에서 혈관내피세포에 붙는 U937세포의 수는 현저히 증가하였다. 그러나 EPA를 U937세포에 25, 50, 100, 200 ㎛의 농도로 6시간 처리 후에 lipopolysac-charide를 처리한 제대정맥 내피세포에 부착(adhesion)시켰을 때 처리한 EPA의 각 농도에 따른 부착된 U937세포의 수는 통계적으로 유의한 차이를 나타내지 못했다. EPA처리가 부착된 U937세포의 수에 영향을 미치지 못하였다. 결 론: EPA는 U937세포에 영향을 미쳐 혈관내피세포-U937 세포부착을 감소시키지는 못하였다. 따라서 EPA에 의한 혈관내피세포-단핵구 부착 억제 효과는 EPA의 단핵구에 미치는 영향에 의하지는 않는 것으로 생각되나 추후 더 많은 연구가 필요하리라 생각된다. Background : Epidemiological studies have shown correlation between low incidence of coronary heart disease and high consumption of fish products. It has been suggested that this may be due to the high content of polyunsaturated fatty acids of the n-3 fatty acid group in fish oil. In animal studies eicosapentaenoic and (EPA) inhibited attachment of monocytes to the arterial endothlium. Method : Adhesion assay was performed on the endothelial cells of the human umbilical vein with 25, 50, 100, 200 ㎛ EPA-treated U937 cells. The endothelial cells were activated with lipopoysaccharide (LPS). The adhesion assay was repeated with oxidized EPA. EPA was oxidized with CuSO4 and ascorbic acid. Result : Viability of U937 cells were not afected by concentrations up to 200 ㎛ of EPAand oxidized EPA. LPS treatment of endothelium notably increased the number of U937 cells attached to endothelial cells on the adhesion assay. However, treatment of EPA, native or oxidized, to U937 cells did not afect the number of U937 cells attached to LPS activated endothelial cells. Conclusion : EPA treatment, native or oxidized, of U937 cells did not affect U937 cell-endothlial cell adhesion. This suggests that inhibition of monocyte-endothlial cells ◎attachment by EPA is not due to the effects of EPS on monocytes.(Korean Circulatin J 1998;28(4):606-610)

골반 자세 변화에 따른 일어서기동작의 운동형상학적 분석과 근전도 연구

최종덕,권오윤,이충휘,김종만,김진경 한국전문물리치료학회 2003 한국전문물리치료학회지 Vol.10 No.2

The purpose of this study was to analyze the effects of three different pelvic tilts on sit-to-stand ativities and to suggest a new therapeutic approach for movement reeducation in patients who have difficulty with sit-to-stand activities. The three different pelvic tilts were: (1) comfortable pelvic tilt sit-to-stand (CPT STS), (2) posterior pelvic tilt sit-to-stand (PPT STS) and (3) anterior pelvic tilt sit-to-stand (APT STS). To analyze the kinematic component of STS, a motion analysis system (Zebris) was applied to the ankle, knee, hip joint, and thigh-off area. Also, to determine the onset time of muscle contraction, surface electrodes were placed to the rectus femoris muscle (RF), the vastus lateralis muscle (VL), the biceps femoris muscle (BF), the tibialis anterior muscle (TA), the gastrocnemius muscle (GCM), and the soleus muscle (SOL). One-way repeated ANOVA was used for the statistical analysis. First, significant differences were found in kinematic variables for the hip, knee, ankle joint, and thigh-off among the three activities. Second, there was significant difference in muscle activation pattern in TA, VL. and BF among three activities. In conclusion, the findings of this study suggest the following evaluative and therapeutic approach for STS activity: (1) Changes in knee and ankle joints should be prioritized and recruitment order differences in VL and RF can be generated to accomplish abnormal STS activity. (2) APT STS can be introduced for movement efficiency and functional advantage when abnormal STS is treated.

좌심실비후 환자에서 베타차단제의 급중단이 임상증상 및 좌심기능에 미치는 영향

황종현,김영태,배용학,임현주,조용근,채성철,전재은,박의현 慶北大學校 醫科大學 1997 慶北醫大誌 Vol.38 No.1

목적 : 베타 차단제와 칼슘 길항제의 장기투여로 안정상태에 있는 비후형 심근증이나 고혈압성좌심실비후 환자에서 이들 약제를 갑자기 중단하였을 때 혈역학, 심기능 및 임상상에 미치는 영향을 알아보기 위하여 본 연구를 시행하였다. 대상 및 방법 : 경북대학교 병원 순환기내과에서 통원치료중인 비후형 심근중 환자 5명과 심한좌심실비후를 동반한 고혈압 환자 6명(남자 6명, 여자 5명)을 대상으로 장기투여 중이던 베타 차단제와 칼슘 길항제를 최소 5일 중단한 후 임상증상, 혈압 및 심박수의 변동, 그리고 투약중지 전후에 도플러 심초음파도를 기록하여 좌심실내경, 벽두께, 좌심실근량, 구혈율 및 승모판혈류속도곡선의 변화를 관찰하였다. 결과 : 1) 약물치료 중단 후, 베타차단제의 경우 9명 중 6명에서, 그리고 칼슘길항제 및 디소피라미드를 복용하던 각 1명, 도합 7명의 환자에서 심계항진, 호흡곤란의 악화, 흉통이 관찰되었고, 심계항진을 호소한 1예에서는 심방세동이 재발되었다. 2) 혈압, 심박수, 확장말기 및 수축말기 좌심실내경, 심실중격 및 심실후벽 두께, 좌심실근량 및 구혈을 모두는 치료약물 중단 전후에 다소 변화하였으나 유의하지 않았다. 3) E파 최고속도와 E파 시간속도적분은 약물투여 중단 전후에 유의한 변화는 없었으나, A파 최고속도와 A파 시간속도적분은 중단 후에 각각 유의하게 증가하였으며(both P<0.01), E/A 최고속도비와 E/A 시간속도적분비는 각각 유의하게 감소하였다(both P<0.01). 한편, E파 감속시간, 등용이완시간 그리고 A-Ar 간격[A파의 최고점에서 A reversal(Ar)파의 최저점간의 시간] 모두는 중단 후 유의한 변화가 없었다. 1 결론 : 비후형 심근증 이나 고혈압성 좌심실비후 환자에서 장기투여중이던 베타 차단제와 칼슘길항제를 일시적으로 중단하였을 때 임상중상의 악화와 더불어 확장기 기능의 변화를 초래하였다. 따라서 약물치료로 비록 임상적으로 안정상태에 있더라도 치료를 갑자기 중단할 때는 주의해야 할 것으로 생각된다. Objectives : This study was done to evaluate the changes in clinical findings, hemodynamics and cardiac function after abrupt withdrawal of longterm beta-blockers and/or calcium channel blockers in hemodynamically stable patients with hypertrophic cardiomyopathy and left ventricular(LV) hypertrophy associated with hypertension. Methods : Eleven patients with hypertrophic cardiomyopathy(n=5) and LV hypertrophy associated with hypertension(n=6) were studied. Symptom assessment, blood pressure, electrocardiography and echocardiography including pulsed Doppler examination were obtained before and at least 5 days after abrupt cessation of beta-blockers and calcium antagonists. Results : 1) Deterioration in symptoms(i.e. palpitation, aggravation of dyspnea and chest pain) was observed in seven patients after abrupt withdrawal. 2) There were no significant changes in blood pressure, heart rate, end-systolic and end-diastolic LV dimensions, interventricular septal thickness, LV posterior wall thickness, LV mass, and ejection fraction before and after drug withdrawal. 3) Doppler time intervals and E wave peak-velocity and time velocity integral(TVI) were not significantly changed before and after drug withdrawal. But A wave peak-velocity and TVI after abrupt withdrawal were significantly increased(both p<0.01), and E/A peak-velocity ratio and TVI ratio were significantly decreased(both p<0.01). Conclusions : These findings suggest that temporary omission of beta blockers and calcium channel blockers develops deterioration in symptoms and LV diastolic dysfunction in hypertrophic cardiomyopathy and LV hypertrophy associated with hypertension. Physicians should avoid abrupt withdrawal of longterm beta blockers in LV hypertrophy.

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.