Consideration of Diluents Selection and Input Amounts of the Hunter Process for Tantalum Production

Jae‑Jin Sim,Sang‑Hoon Choi,Yong‑Kwan Lee,Sung Gue Heo,Taek‑Soo Kim,Seok‑Jun Seo,Kyoung‑Tae Park 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.7

Tantalum (Ta) is a heavy refractory metal with an atomic weight of 180.95 g/mol, a density of 16.6 g/cm3, and a high meltingpoint of 3017 °C. With its refractory characteristics, it shows excellent chemical and physical stability as well as corrosionand heat resistance at elevated temperatures. The demand for Ta metal and related compounds is increasing with the expansionof the electronics and chemical industries. The Hunter process was proven to be effective in producing Ta powder in1953. Hunter proposed a method in which potassium heptafluorotantalate (K2TaF7) was reduced by sodium (Na). Thus far,this process has been the primary commercial method to produce Ta powder. In this study, quantitative differences wereanalyzed for diluent selection. Additionally, consideration was given to changes in the caloric value depending on the inputamount of diluents. Finally, the optimum material input and the properties of the prepared Ta were analyzed. Stoichiometricratios of K2TaF7(1 mol), NaCl (6.2–6.7 mol), Na (5–7 mol) were weighed, to perform a metallothermic reduction reaction. After the reaction, the tantalum powder was recovered and the flush process was carried out. After that, it was dried in avacuum atmosphere. Physical properties such as oxygen concentration, PSA, ICP-OES, and XRD of powder were conductedto evaluate the characteristics of Ta powder that was finally manufactured.

유전성 비용종증 대장암의 임상적 고찰

서정민,박재갑,최국진,김진복,서정민,박재갑,최국진,김진복 대한대장항문학회 1992 Annals of Coloproctolgy Vol.8 No.2

FDM에서 Build Orientation이 쾌속조형물의 표면에 미치는 영향

전재억,서진호,권광진,권혁준,정진서,하만경 한국공작기계학회 2002 한국공작기계학회 춘계학술대회논문집 Vol.2002 No.-

Fused deposition (FD) modeling by Stratasys Inc., is one of the material deposition subfamilies of solid freeform fabrication (SFF) technologies. In this process, build material in the form of a flexible filament, is heated to a semi-liquid state and extruded from a controlled deposition head onto a fixtureless table in a temperature controlled environment. The position of nozzle is computer controlled relative to the base, which allows geometric complex models to be made to precise dimensions. FDM provide what the part was directly tested by the worker. It provide believable data. This Study is identify to surface roughness by build orientation adjustment. So, the paper is the study on surface roughness by build orientation at FDM.

유전성 비용종증 대장암 1예

서정민,박재갑,김상준,김진복,서정민,박재갑,김상준,김진복 대한대장항문학회 1991 Annals of Coloproctolgy Vol.7 No.2

스쿠알렌 합성 유전자를 도입한 형질전환 가시오가피

서진욱,정재훈,최용의,이학성,신차균 중앙대학교 유전공학연구소 2003 遺傳工學硏究論集 Vol.16 No.1

The enzyme, squalene synthase, represents a branch point in the isoprenoid pathway capable of diverting carbon flow specifically to the biosynthesis of phytosterol and Triterpenoid. Transgenic Eleutherococcus senticosus plants were prepared by introducing the genes for squalene synthase derived from Panax ginseng (PgSS1), hygromycin phosphotransferase (HPT) and green fluorescent protein (GFP) through Agrobacterium-mediated transformation. Establishment of transgenic plantlets were confirmed by the presence of PgSS1 and HPT bands in the genomic DNA preparation using a PCR method and a Southern blotting. In addition, expression of the introduced GFP DNA was confirmed by observing green fluorescence of GFP from the embroyos. In the in vitro analysis of the PgSS1 enzymatic activities the transgenic plants showed to have 1.5 to 3 times higher than wild type plant, indicating that the PgSS1 genes was well over-expressed in the transgenic plants. Especially the PgSS1 acivities of embroyogenic cell was 120 times higher than those of plantlet.

중등학교 교과서의 농업·농촌 기능 분석 및 반영 방안

서우석,강대구,정진수,김절용,김재호,이윤조 한국농업교육학회 2007 농업교육과 인적자원개발 Vol.39 No.2

관상동맥 누공에 의한 급성 심근 경색 1예

서유승,최재웅,송창섭,조용범,양진수,박준섭,정인수 대한내과학회 2003 대한내과학회지 Vol.65 No.2

관상동맥 동정맥루 기형은 매우 드문 질환으로 치료가 불필요한 경우가 대부분이나 coronary steal 현상으로 인해 증상이 발생하거나 합병증이 발생한 환자에 대해선 치료를 요한다. 최근에는 시술에 적합한 누공을 가진 선택된 환자군을 대상으로 카테터를 이용한 중재적 시술이 시행되어 수술적 치료와 유사한 결과를 얻고 있다. 저자들은 젊은 남자에서 관상동맥 동정맥루 기형과 동반된 급성 심근 경색증을 진단하여 비 수술적 방법인 카테타 코일 색전술로 성공적 치료 후 증상 및 심근 재관류에 호전을 보인 증례를 경험하였기에 문헌고찰과 함께 보고하는 바이다. We report a case of coronary fistula between the left anterior descending and main pulmonary artery complicating acute non-Q wave myocardial infarction. A 27-year-old man visited emergency department because of severe chest pain lasting two hours. The electrocardiogram showed ST segment elevation in precordial leads V3~6. Cardiac enzymes were as follows;CK-MB:36.44 IU/L T-T:0.489 ng/mL, CPK:542 IU/L, and LDH:475 IU/L. The thallium-201 dipyridamole stress perfusion scan showed perfusion defect and reversed redistribution in the anteroseptal wall. The coronary angiogram revealed coronary artery fistula between the proximal left anterior descending artery and main pulmonary artery without significant stenoses of coronary arteries. The result of ergonovine test was negative. After micro-coil embolization to the coronary fistula, symptoms were improved. Follow-up thallium-201 scan showed normalized blood flow in the left anteroseptal wall.

30-60대 건강한 서울시민의 脚筋伸展파워 및 신체작업능력 : 동경 및 북경시민과의 비교 Comparison of Tokyo and Peking Residents

서재균,김승일,최영렬,방영진,김형돈,전병관,선우섭,손두옥 한국학교체육학회 1999 한국학교 체육학회지 Vol.9 No.1

본 연구는 한국인의 삶의 질 향상을 위한 국민 생활체육 진흥정책 수립에 필요한 기초자료를 제공하기 위하여, 건강한 30-60대 서울시민(313명)의 체격과 근력, 전신지구력 등의 체력을 측정하여 문화, 경제생활수준이 서로 빠른 동경시민(509명) 및 북경시민(160명)과 비교 검토하는 것을 목적으로 하였다. 각국의 연구대상에 대한 측정은 사전에 협의한 동일한 방법(동경대학 체육과학실법)과 기기를 이용하였다. 체격요인으로는 신장과 체중을, 체력요인으로는 트레드밀 보행시 (90m/분)의 심박수와 보폭 그리고 자전거 에르고미터 운동시의 PWC75%HRmax와 脚筋伸展파워를 측정하였다. 신장 및 체중, 신체질량지수는 남녀 모두 북경, 서울, 동경시민순으로 높게 나타났다. 트레이드밀 보행시의 심박수는 남녀 모두 북경, 동경, 서울시민 순으로 낮은 값을 보였으며, 신장에 대한 보폭비율은 남자의 경우에는 북경, 서울, 동경의 순으로, 여자는 북경, 동경, 서울의 순으로 높았다. 脚筋伸展파워는 60대 여자를 제외한 남녀 모두 북경, 서울, 동경시민의 순으로 높았으며, PWC75%Hrmax는 남자 40대 와 여자 30대를 제외한 모든 연령 대에서 서울시민이 동경시민 보다 높은 경향을 나타냈다. 한편 모든 피검자를 대상으로 연령과 脚筋伸展파워와의 회귀식은 남녀 각각 Y=-0.30X+28.88(n=230, r=0.61, p<.001), Y=-0.l0X +12.49(n=611, r=0.32, p<.001), PWC75%HRmax와의 회귀식은 남녀 각각 Y=-0.01+ 2.50(n=116, r=0.29, p<.01), Y=-0.l0X+1.89(n=461, r=0.20, p<.001)이였다. 따라서 30~60대 서울시민의 체격 및 脚筋伸展파워는 북경시민 보다 낮게 나타나 삶의 질 향상을 위해 보다 적극적인 사회체육 활성화 방안 마련이 요망된다. The purpose of this study was to serve as a basis for making a health promotion policy for better quality of Korean life, by examining 313 citizens of Seoul's physical and leg extension power, physical working capacity who were in their thirties to sixties, enjoying good health, and by making a comparison of tile result with that of 509 citizens of Tokyo and 160 citizens of Peking who lived in different culture and living environment. The findings of this study were as below: First, the male citizens of Peking, who were in their forties to sixties, and the female citizens of the same city, who were in their fifties to sixties, were significantly higher in height, body weight and body mass index. Second, the male citizens of Peking, who were in their thirties and sixties, and the female citizens of the same city, who were in their thirties to forties, were significantly lower in heart rate in walking in the treadmill(90n/min). And there was a tendency that the citizens of Peking showed a higher ratio of stride to height. Third, the male citizens of Peking, who were in their fifties, and the female citizens of the same city, who were in their thirties to forties, had a significantly better leg extension power. As a result of examining all the subjects, there was a negative correlation between leg extension power and age. Fourth, all age groups of Seoul citizens, except males in their forties and females in their thirties, fended to be better in PWC75%HRmax than the citizens of Tokyo. When all the subjects were examined, there was a negative correlation between PWC75%HRmax and age. Consequently, there was a need to prepare more active plan to step up sports fur all successfully in order to improve the quality of life, as the citizens of Seoul who were their thirties to sixties appeared to be inferior in physical physique and leg extension power to the citizens of Peking.

Substance P의 기니피그 위 유문동 윤상근에 대한 수축 및 전기적 효과

서종옥,이승곤,김종승,전제열,여철호,윤평진 조선의대 1995 The Medical Journal of Chosun University Vol.20 No.2

FeCoB계 아몰퍼스 자성박막의 임피던스효과에 관한 연구

서강수,정승우,임재근,신용진 명지대학교 대학원 1997 대학원논문집 Vol.1 No.-

In this paper, we has studied frequency dependence of impedance of FeCoB amorphous magnetic films. First, we investigated optimal composition and sputtering conditions for fabrication of zero magnetostrictive amorphous magnetic films. (Fe_(1-x)Co_x)_79Si_2B_19 was selected as the basic composition and then, the films were fabricated with x=0.94 and 0.95 respectively by using sputtering method at high frequency. In order to relieve the internal pressure and derive the magneto-anisotropic. we annealed the films in about 150[Oe] of magnetic field and in the range(280℃, 300℃ and 320℃ respectively) of crystallization temperature(360℃). In addition, we annealed the films under non-magnetic field and near crystallization temperatures (283℃/30min, 400℃/30min and 400℃/1hr respectively) in order to decrease magnetoanisotropic. Then, we investigated magnetic properties including magneto-impedence and inductance. As the results, we found excellent magnetic characteristics and high impedence changing rate(4.52[%/Oe]) when we fabricated a sample under the condition that input power 400[W], Ar gas pressure 6.4[mTorr]. sputtering time 30[min] and annealing time 30[min] at 300[℃] in 150[Oe] magnetic field Especially, the impedence changing rate which was basic characteristic of Ml element was 4.52[%/Oe] for x=0.94. Moreover, the inductance values of the samples annealed at 400[℃/30min] were higher by 132[%] to 197[%] than those of the non-annealed samples. In addition, the quality factor Q was below 0.7 for all samples. Consequently, we find that the zero magnetostrictive amorphous magnetic film can be used as a magnetic sensor material.