Study on Microstructure and Mechanical Properties of the Al–25Cr–5Si (at%) Alloy Powder Using Gas-Atomization and SPS Process

Yong‑Ho Kim,Hyo‑Sang Yoo,Jeong‑Han Lee,Ik‑Hyun Oh,Hyun‑Kuk Park,Hyeon‑Taek Son 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.7

In order to investigate the microstructure and mechanical properties on Al–25Cr–5Si (at%) alloy, a mixed powder with pureelements and an alloy powder using a gas atomization process were used. Fine and high purity Al–25Cr–5Si (at%) alloypowder was successfully prepared by gas atomization and densified using a spark plasma sintering (SPS) process. The overallpowder size distribution of the mixed Al, Cr, and Si elemental powders was in the range of 10–15 μm. The atomized Al–Cr–Sialloy powder was fine and spherical in morphology and difficult to be formed by intermetallic formation. Densification wasclearly confirmed at 1000 °C, with almost isolated pores formed, by clear removal of pores between particles, deformationof particles, an increase in the number of contacts, and a change in size between particles. As a result of XRD analysis ofthe sintered compacts, single phase was observed using the mixed powder, but the compact using gas atomization remainedthe alloy phase even at the process temperature. The Vickers hardness of the compacts by mixed powder was observed at59.70 Hv and the compact using gas atomized powders on the temperature 1000 °C of the Vickers hardness increased to702.6 Hv. The compressive yield strength of the compact with mixed powder was 195.24 MPa and the compressive strengthof the compact with gas atomized powder increased to 802.07 MPa. It is considered not to be decomposed by the AlCrSi,Al13Cr4Si4and Al8Cr5phases sintering process, resulting from the improvement of mechanical properties.

감과실에서 분리한 효모의 특성

정용진,김주현,이명희 東國專門大學 1997 金龜論叢 Vol.4 No.1

감과실에서 분리하여 탄닌물질에 내성이 있고 알콜발효력이 우수한 Saccharomyces cerevisiae YJK 20과 Saccharomyces kluyveri DJ 97의 배양학적 특성을 조사하였다. 그 결과 배양은도 30℃ YJK 20, DJ 97은 알콜수율이 95.62%, 94.43%로 가장 높았으며, 초기 pH의 영향은 YJK 20은 pH 6.0에서 DJ 97은 pH 5.0에서 각각 95.76%, 95.23%로 가장 높았다. 그리고 진탕속도의 영향은 두균주 모두 150rpm 이상에서 수율이 감소하는 경향이었다. 또한 초기 당농도에 의한 영향에서는 YJK 20은 150g/ℓ의 농도에서 97.55%, DJ 97은 100g/ℓ의 농도에서 96.55%로 가장 높은 수율을 나타내었다. 따라서 두균주는 식초의 기질이 되는 감알콜발효의 수율을 높일 수 있는 우수한 균주로 선별할 수 있었다.

대구·경북지역의 전통발효식품 이용에 관한 실태조사

정용진,김주현 동아시아식생활학회 1996 동아시아식생활학회지 Vol.6 No.3

This survey was carried out to investigate the usage of traditional fermented foods. Questionaries were answered by 283 female adults ranging from 20 to 60 ages in Daegu city and Kyungbuk province. 39.72% of total subjects answered that they made Meju and soybean paste by themselves. There were significant differences according to income, residential area, education level, and family size. In the results of the preference and consumption study on traditional soybean pastes, Kimchi and salted sea foods, preference of salted sea foods was the highest, whereas the consumption of salted sea foods was the lowest. The recognition of soybean pastes and traditional foods was remarkably low. However, the consumption frequency of traditional fermented foods and the recognition of soybean pastes and traditional foods were significantly increased with age.

대구·경북지역 성인여성의 식습관과 영양보충제의 복용에 관한 연구

김주현,정용진 東國專門大學 1996 金龜論叢 Vol.3 No.1

본 연구는 대구 및 경북 일부 지역에 거주하는 성인 여성을 대상으로 식습관 및 영양보충제의 복용 정도에 관한 설문조사를 실시하였다. 조사대상자의 나이는 37.0±8.1였고 BMI는 21.5±2.6이었다. 나이와 BMI 사이에는 유의적인 상관관계를 보였다(p<0.01). 또 질병 여부를 조사한 결과 위장질환이 가장 높게 나타났다. 영양 보충제의 복용정도를 조사해 보았을 때 조사자의 61.9%가 복용하지 않는 것으로 나타났으나 수입의 증가에 따라 복용정도는 증가하는 경향을 보였다. 운동여부를 조사한 결과 조사자의 43.1%가 운동을 거의 하지 않는 것으로 나타났다. 채소류의 기호도가 비교적 높게 나타났으며 외식시 한식을 선호하는 경향이 약 94%까지 높게 나타났다. 성인병의 예방을 위한 올바른 식이 섭취는 개인의 체격조건, 운동량, 식품기호도를 고려하여야 하며, 실제 생활에 적용되는 구체적인 영양교육 및 영양개선 프로그램의 보급이 절실하다고 사료된다.

대퇴동맥을 통한 경피적 관동맥 중재시술 환자의 천자부위 지혈을 위한 Angioseal^(�) 사용과 고식적 용수 압박법의 비교 : 전향적 연구

김용훈,권현철,김필호,안석진,유철웅,최진호,이상철,김준수,김덕경,전은석,이상훈,홍경표,박정의,서정돈 대한내과학회 2004 대한내과학회지 Vol.66 No.5

목적 : 경피적 관동맥 중재술은 최근 양적 및 질적으로 급격한 발전을 보였지만 시술 시 천자부위의 혈관 합병증은 아직 해결해야 할 문제점이다. 저자들은 대퇴동맥을 통한 경피적 관동맥 중재술을 환자에게 천자부위 지혈을 위한 혈관폐쇄기구인 안지오실의 안전성과 유용성을 고식적인 용수 압박법과 비교 연구하고자 하였다. 방법 : 2002년 4월부터 2003년 5월 사이에 삼성서울병원 심장혈관센터에서 대퇴동맥을 통한 경피적 관동맥 중재술을 성공적으로 시행한 200명의 환자(안지오실 사용군: A군, 100명, 고식적 용수압박법 사용군 B군, 100명)를 대상으로 시술 후 주요 합병증 및 경한 합병증, 지혈 후 환자가 자리에 앉기까지의 시간, 보행개시 가능시간, 총 재원 기간과 시술 1주 후의 합병증을 전향적으로 조사하여 비교 연구하였다. 결론 : 두 군에서 연령, 성별, 기저질환, 심혈관 질환의 위험요소, 시술의 종류, 시술 중 사용한 헤파린의 양, clopidogrel의 양, ticlopidine의 양, 지혈 시 수축기와 확장기혈압, ACT (activated clotting time)는 차이가 없었다. A군이 B군에 비해 시술 후 자리에 앉기까지의 시간 (A군: 4.3±0.3시간, B군: 13.7±0.8시간, p=0.004) 및 보행개시까지의 시간(A군: 6.8±0.5시간, B군: 18.8±2.1시간, p=0.013)이 유의하게 짧았다. 시술 후 주요 합병증은 두군 모두에서 관찰되지 않았으며, 경한 합병증의 전체발생은 A군에서 유의하게 적었다(A군: 28명, B군: 19명, p=0.003). 반상출혈의 경우는 A군에서 유의하게 낮았지만(A군: 3명, B군: 12명, p=0.01), 혈종, 출혈의 발생은 두군간에 차이가 없었다. 총 재원기간에는 두 군간에 차이가 없었다(p=0.239). 시술 1주 후 경과관찰에서 주요합병증은 역시 두 군 모두에서 관찰되지 않았으며, 경한 합병증의 전체발생은 두 군에서 차이가 없었다(A군: 15명, B군: 13명 p=0.418), 반상출혈의 빈도는 차이가 없었지만 혈종의 발생은 A군에서 더 낮았다(A군: 2명, B군:6명, p=0.004). 두 군 모두에서 출혈은 발생하지 않았다. 결론 : 대퇴동맥을 통한 경피적 관동맥 중재술을 시행한 환자에서 안지오실의 사용은 고식적 용수 압박법에 비해 환자의 침상 안정시간을 줄여 조기 활동개시가 가능하게 하였으며 국소합병증의 위험도를 일부 낮추어, 시술에 따른 환자의 불편을 현저하게 감소시킬 수 있다고 할 수 있을 것으로 기대된다. Background : Although the number and the quality of percutaneous coronary intervention have been recently increased dramatically, the vascular complication at puncture site is still the major cause of patients' morbidity. We evaluated the safety and efficacy of newly of newly-developed collagen-based arterial closure device, Angioseal after transfemoral percuatenous coronary intervention. Methods : This study was designed as a prospective single center non-randomized comparative study. A total 200 patients undergoing transfemoral percutaneous coronary intervention were enrolled between April 2002 and May 2003. They were divided into two groups; Angioseal group (group A, n=100) and manual compression group (group B, n=100). The baseline clinical and angiographic characteristics were reviewed. The time to sit up, the time to ambulation, the duration of hospital stay, major and minor vascular puncture site complications were monitored. The patients were followed-up for 1 week after procedure by telephone. Results : The baseline clinical characteriwtics, clinical diagnosis, cardiocascular risk factors, typesof procedure, doses and numbers of anticoagulants were similar between two groups. The blood pressure and activated clotting time were also similar. The time to sit up (group A: 4.3±0.3 hours, group B: 13.7±0.8 hours, p=0.004) and the time to ambulation (group A: 6.8±0.5 hours, group B: 18.8±2.1 hours, p=0.013) were shorter in group A. No major vascular complications were noted. The incidence of hematoma and bleeding were not significantly different between two groups. The incidence of ecchymosis, however, was significantly lower in group A (group A:12%, group B: 3%, p=0.001) The duration of gospital stay was similar between groups. During 7 days of follow-up period incidence of hematoma was significantly lower in group A (p=0.004). Although the incidence of ecchymosis was not significantly different between two groups. Conclusion : The angioseal may be associated with earlier ambulation and less patients' morbidity with low incidence of local complication rate compared to manual compression after transfemoral percutaneous coronary intervention.

원발성 폐암 환자의 생존율에 관한 보고

김현태,이상무,어수택,박춘식,정성환,허승재,남충희,강창희,김용훈 순천향대학교 1994 논문집 Vol.17 No.4

We analysed 404 patients with primary lung carcinoma who were treated at Soonchunhyang University Hospital from July, 1985 to september, 1993 in order to investigate the survival rate and epidemiolgical properties of primary lung cancer. They were 330 males and 74 females. The most prevalent decade was seventh. In terms of cell type, the squamous cell was 225 patients (55%), and adenocarcinoma, small cell, mixed type was 21%, 19%, 4%, respectively. Among non-small cell lung carcinoma, stage Ⅲa was the most prevalent one(92%). In case of small cell carcinoma, the limited stage was 64%. The 12-, 24-, 36- month survival rate of total patients was 57%, 31%, 22%, respectivley and median sruvival time was 15 months. The 36-month survival rate tended to be longer in non-small cell lung carcinoma than that of small cell lung cancer, but there was no difference between two groups, statistically. In non-small cell carcinoma, The 36-month survival rate and meidan survival time were longer in the stage Ⅰ and Ⅱ than those of Ⅲa, Ⅲb, Ⅳ (80% versus 38%, 22%, 0%, p<0.05). According to involvement of lymph node, the 36-month survival rate was longer in NO and N1 than those of N2, N3 (61.9%, 48.7% versus 17.7%, 17.3%, p<0.05). In small cell carcinoma, The 36-month survival rate and median survival rate were higher and longer in limited stage than those of extensive stage(16.1% and 13 month vs 10% and 8 month, p<0.05). In conclusion, we report here the incidence of primary lung carcinoma and the survival rate of paients with primary lung carcinoma who were treated in Soonchunhyang University Hospital.

S.D. Rats를 이용 1, 1-Dichloro-1-fluoroethane의 아민성 흡입독성 연구

김현영,이성배,임철홍,김철우,점용현,한정희,전윤석,최수영,강대봉,이용묵 한국환경독성학회 2002 환경독성보건학회지 Vol.17 No.1

There were no specific effects for test materials on Sprague-Dawley (S.D.) rats in clinical symptoms, amounts of food intakes, weight changes, laboratory findings, and pathology after whole body l, l-Dichloro-1 -fluoroethane (used as coolant, metal cleaner and solvents) exposure(0, 1,500, 3,000, and 6,000 ppm) for 13 weeks (6 hour/day, 5 days/week). However, the loss of capillary vessels in eyeball (pupil) was observed in a female rat among 6,000 ppm group. Though there was a tendency for MCHC (Mean Corpuscular Hemoglobin Concentration) in rat to be decreased (p<0.05), it was not regarded as abnormal because the values were within normal limits. In asthma-stimulation related evaluations, there was also a tendency for inflammatory cell counts in bronchoalveolar lavages to be increased. But it had no statistical significance, and also no dependency on sex and the exposed concentration. Based on this result, the non observed effect level (NOEL) induced by 1, 1-Dichloro-l -fluoroethene inhalation was evaluated in groups with 3,000 ppm below (S .D. Rats, 13 weeks). Finally, it was concluded that the short term exposal of 1, 1-Dichloro-l-fluoroethane is not considered as a asthma stimulant by inhalation despite of some study limitations such as test animals use and short-term exposure .

운동이 지단백대사에 미치는 효과

김주현,정용진 東國專門大學 1997 金龜論叢 Vol.4 No.1

현대인의 활동량과 운동량은 급속도로 감소되고 있으며, 특히 coronary heart diease(CHD)의 위험인자의 감소를 위한 운동처방이 증가되고 있다. CHD의 예방을 위해 CHD의 위험인자중 가장 널리 인지되고 있는 lipoprotein의 수준에 미치는 운동의 효과를 조사하였다. 운동선수의 HDL-C의 수준은 일반인에 비해 유의적으로 높았으며, 운동동안 그 수준이 상승되었다. 또 평소 운동이 전혀 없던 일반인에게 낮은 강도의 유산소 운동을 실시하거나 endurance exercise를 실시한 경우에도 체내의 lipoprotein의 성분과 혈장의 지방수준이 변화하였다. 한편 여가시간의 활동정도 차에 의한 변화 역시 유의적으로 나타났다. 운동은 실시한 운동의 종류, 강도, 기간 대상자의 평소의 활동상태에 따라 lipoprotein의 변화가 상이하게 나타나는 양상을 보인다. 운동에 의한 lipoprotein의 변화는 여러 기전에 의해 일어나는 것으로 제기되고 있다. 운동량의 증가는 근육에서 소비되는 지방산의 증가를 요구하여 LPL 활성이 증가되고 증가된 LPL활성은 chylomicron과 VLDL로 부터 TG, cholesterol, phospholipid, apolipoprotein을 방출시킨다. 운동에 의해 HDL의 subfraction도 변화되는데, 증가된 LPL와 HTGL의 수준의 감소에 의해 HDL3보다 HDL2의 subfraction이 증가된다. 한편 LCAT는 증가되어 HDL3 표면의 free cholesterol, fatty acid로 부터 cholesterol ester를 형성하여 HDL molecule의 중심으로 이동하여 HDL3는 HDL2로 전환을 촉진시킨다. CETP는 운동에 의해 감소되어 HDL의 esterified cholesterol이 VLDL과 LDL로 net transfer되는 경우가 감소하게 된다. 운동이 CHD에 미치는 효과는 운동자체의 효과 뿐 아니라 대상자의 생활 환경의 여러 요인과 관련되므로 식이 조건등 여리조건을 통제시킨 연구가 계속되어야 한다고 사료된다.

소목(Caesalpinia sappan) 추출물의 Streptococcus mutans에 대한 성장, 산생성, 부착 및 비수용성 글루칸 합성 억제에 미치는 영향

유용욱,유현희,김윤정,유미선,서세정,이황,이흥수 대한구강보건학회 2003 大韓口腔保健學會誌 Vol.27 No.2

Streptococcus mutans is known as the causative bacterial playing the most important role in forming plaque and it is being noticed as major causative bacteria of dental caries. Therefore, development of more effective, substantial and safe preventive agent against dental caries and periodontal disease is honestly required. The present study was designed to investigate the effect of chloroform extract(CE), n-butanol extract(BE),methanol extract(ME) and water extract(WE) of Caesalpinia on the growth, acid production, adhesion, and insoluble glucan synthesis of Streptococcus mutans. The CE, BE, ME and WE decreased the growth and acid production of S.mutans than that of control, especially, the ME was more effective than other extracts. The effect of CE, BE, ME and WE on the adherences to saliva-coated hydroxyapatite bead(S-HA) were evaluated. At the concentration of 2,000 ㎍/㎖, the CE showed 32% rate of bacterial adherence to S-HA, whereas, other extracts of the same concentration producedgreater than 50% rate. The CE and BE were significantly decreased the reduction rates of water insoluble glucan formation from sucrose by crude glucosyltransferase of S.mutans. Thus, the application of C. sappan can be considered a useful and a practical method for the prevention of dental caries.

고령 폐결핵환자(60세 이상)에서의 방사선학적 소견

박정희,진용현,임종남 건국대학교 의과학연구소 1999 건국의과학학술지 Vol.9 No.-

In this elderly patients, incidence of pulmonary tuberculosis is very high because of the decreased function of the body immune system and combined diseases. We analysed radiographic findings of 51 patients with pulmonary tuberculosis to compare with the typical findings of reactivation pulmonary tuberculosis in the adult over 60 years old. The typical location of reactivation pulmonary tuberculosis is the apicoposterior segment of the upper lobe and the superior segment of the lower lobe. But in elderly patients of our study, 38cases(76%) showed lesions also in atypical location such as the anterior segment of the upper lobe, the middle lobe, or the basal segments of the lower lobe. Also 36cases(72%) showed multilobar extents, 30cases(59%) showed unusual findings and 26cases(52%) showed multiple cavities and in 19 cases(38%), differential diagnosis with lung cancer was difficult. Especially in patients with diabetes mellitus, involvement of the anterior segment of the upper lobe was significantly high compared with the patients without DM.