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.

Preparation of mechanically enhanced supramolecular carbon nanotube (CNT) film using a water‑soluble π–π bonding linker

Jun‑Woo Lee,Moonseong Yoo,Kun Won Kim,Hyein Jeong,Jae Woo Chung 한국탄소학회 2019 Carbon Letters Vol.29 No.5

Mechanically enhanced supramolecular carbon nanotube (CNT) films were prepared in water by employing the π-electronrich phenyl, naphthalenyl, and pyrenyl end-functionalized polyethylene oxides (PEOs) as supramolecular linkers, followed by vacuum filtration. Among them, the supramolecular CNT film produced by the pyrenyl end-functionalized PEO (PEOPy) exhibited the highest mechanical strength, which was ~ 1.5–2 times higher than that of the CNT films produced using the typical dispersant, Triton X-100, although the functionality of PEO-Py was lower than that prepared using other linkers, and the content of PEO-Py in the CNT films was lower than that obtained using Triton X-100. Fluorescence and UV–Vis spectroscopy demonstrated that the improved mechanical properties of the supramolecular CNT film result from the formation of π–π interactions between the CNT and the pyrene moieties of the PEO-Py linker. Finally, the supramolecular CNT film exhibited a 40–50 dB electromagnetic shielding efficiency through hybridization with silver nanowires.

가스화 - 수소 회수 공정 개발을 위한 예비실험

차재준(Jae-Jun Cha),김영석(Young-Suk Kim),이진호(Jin-Ho Lee),황순모(Soon-Mo Hwang),정성재(Seong-Jae Jeong) 한국열환경공학회 2010 한국열환경공학회 학술대회지 Vol.2010 No.춘계

자궁경부 상피종양에서 human papillomavirus 감염과 survivin 발현

윤재호,정동준,이정은,박동명,배동한,선우재근,백무준,김창진 순천향의학연구소 2004 Journal of Soonchunhyang Medical Science Vol.10 No.1

Human papillomavirus (HPV) has been considered a causative agent of uterine cervical carcinoma. HPV is a DNA oncogenic virus, which is well known as a causative virus in uterine cervical carcinoma. The virus is classified into two groups genotypically, low risk and high risk, according to the carcinogenic potentiality, and the determination of the viral genotype is important in clinical practice. Recently, numerous genotypes can be determined by high throughput method using DNA chip. Survivin is a recently characterized inhibitor of anti-apoptosis (IAP) protein, which is abundantly expressed in most solid and hematological malignancies, but undetectable in normal adult tissues. In this study, HPV genotypes are determined by DNA chip and the expression of survivin was examined by immunohistochemistry in 80 cases of uterine cervical intraepithelial neoplasia (CIN) and invasive carcinoma to see the roles of HPV and survivin in the carciogenesis of uterine cervical epithelial neoplasia. The results were as follows: 1. HPV positive rate was 72.5%, while negative rate was 27.5% in 80 cases of CIN and invasive carcinoma. The CIN and invasive carcinoma showed higher HPV positive rate (p <0.05). 2. HPV positive rate according to the histologic grade were 60%, 65%, 77% and 90% in CINI, CINII, CINII and invasive carcinoma, respectively. HPV positive rate showed increasing tendency according to the histologic grade, though there was no statistical significance. 3. The most frequent genotype was type 16 and the next were 58, 52, 18 and 33 in order of frequency. 4. Survivin was expressed in 96.3% of CIN and invasive carcinoma. The expression rate of survivin showed no significant difference between the histologic grade of CIN and invasive carcinoma, but showed tendency of increased expression rate in invasive carcinoma. 5. Survivin was expressed in HPV positive and in HPV negative each as in 95.5% and 96.6% respectively. There was no significant difference of survivin expression between HPV positive and negative cases. The above results suggest that HPV has no effect on the regulation of survivin expresson level in the uterine cervical intraepithelial neoplasia and invasive carcinomas.

전해산성수를 이용한 새로운 내시경 소독 시스템(Cleantop WM-1??)의 소독효율

이준행,이풍렬,송재훈,이남용,임윤정,장재권,김영호,김재준,백승운,이종철,최규완 대한감염학회 2001 감염 Vol.33 No.2

Background : Electrolyzed acid water (EAW) is a new liquid chemical germicide containing a mixture of oxidizing species and prepared by mixing a small amount of salt with tap water in an electrolyzer. We attempted an in-use evaluation of the high-level disinfection capability of Cleantop WM-1□, a new endoscope reprocessing system using EAW. Methods : Forty-seven flexible endoscopes were randomly collected just after upper endoscopic examinations and were disinfected using Cleantop WM-1□. Parts of the endoscopes without contact to EAW were disinfected with 75% ethyl alcohol. Immediately after the disinfection procedure, samples were taken from the biopsy channel (S-1), tip of the insertion tube (S-2), the umbilical cord (S-3), and the angulation knob (S-4). Results : In EAW-disinfected parts of the endoscopes, the culture-positive rates were 4.3% (2/47) in S-1 samples and 12.8% (6/47) in S-2 samples. In ethyl alcohol-disinfected area, the culture-positive rates were 2.1% (1/47) in S-3 samples and 25.5% (12/47) in S-4 samples. The colony counts of culture-positive samples ranged from 1 to 144. Pseudomonas aerugi-nasa was recovered from the angulation knob of an endoscope, but other contaminating organisms were mostly : normal flora or opportunistic pathogens. Conclusion : Although part of the endoscopes disinfected with 75% ethyl alcohol were contaminated with more organisms than EAW-disinfected areas, Cleantop WM-1□ showed a relatively good disinfection efficacy in reprocessing patient-used endoscopes. (Korean J Infect Dis 33:133∼138, 2001)

아메바성 대장염과 연관된 Henoch-Scho¨nlein Purpura 1예

장재현,원경준,이준,변유미,이재광,김영훈,박찬국,김만우 朝鮮大學校 附設 醫學硏究所 2006 The Medical Journal of Chosun University Vol.31 No.3

Henoch-SchonIein purpura is a common form of vasculitis primarily involving the skin, the gastrointestinal tract, the joints, the kidneys, and the nervous system. The etiological investigations are essential, because triggering factors are found in approximately half the patients such as viral, bacterial and parasitic infections, drugs, toxins, systemic diseases and cancer. But it's the correlation between Henoch-SchonIein purpura and Entamoeba histolytica has been rarely reported. We report a 29-years-old woman with Henoch-SchoIein purpura complicated by the lower gastrointestinal bleeding caused by the amoebic colitis. She complained of cramping abdominal pain, lower extremity purpura and hematochezia. Cysts and trophozoites of Entamoeba histolytica were detected in her stool. Skin biopsy demonstrated the leukocytoclastic vasculitis. She was administered metronidazole 1,500㎎ a day for the treatment of amebic colitis. Her hematochezia was improved, but the abdominal pain and purpura were not. The subsequent corticosteroid therapy improved her symptoms.

집성재 단면구성에 따른 휨성능 평가

이전제,김광모,한재수,김재건 한국목재공학회 2003 목재공학 Vol.31 No.5

본 연구에서는 몇 가지 새로운 집성재 단면구성 방법을 제안하고, 국산 낙엽송과 합판으로 제조된 집성재의 휨시험을 통해 단면 구성에 따른 집성재의 침성능을 평가 비교하였다. 수평적층(BH), 수직적층(BH), 수직으로 합판보강된 수직적층(BVV)과 수평으로 합판보강된 수직적층(BVH)의 총 네가지 형태의 단면구성 방법에 대하여 실험을 실시하였다. 파괴모드를 관찰하고, 실험을 통해 얻어진 하중-변형 곡선으로부터 MOR 및 MOE를 계산하여 이를 바탕으로 각 단면구성 방법의 휨성능 개선효과를 비교하였다. MOR의 경우에는 결함의 분산으로 인해 수직적층에서 수평적층에 비해 23% 정도의 개선효과를 얻을 수 있었으나, MOE의 경우에는 거의 유사한 값을 나타내었다. 수평으로 합판보강된 경우에는 상대적으로 휨성능이 약한 합판이 사용됨에 따라 MOE가 15% 정도 감소하였으나, 수직으로 합판보강된 경우에는 합판이 사용되었음에도 불구하고 MOE의 감소 없이 MOR이 개선되는 효과를 나타내었는데 이는 전단보강의 효과로 생각되며 이러한 효과를 파괴모드의 관찰을 통해서도 확인하였다. 이상의 결과로부터 집성보의 단면 구성시 라미나의 적절한 배치 및 전단보강 등을 통하여 전체적인 휨성능을 향상시킬 수 있음을 확인하였다. In this paper, bending capacities of glulams with different configurations of cross-section were evaluated. These configurations included horizontal(BH), vertical(BVN), vertical with vertical plywood(BVV) and vertical combination of lamination with horizontal plywood(BVH). Full-scale bending tests were performed to investigate the effect of different section configurations on bending strength(MOR) and stiffness(MOE) of glulam. Compared with type BH, MOR of glulam with type BVN configuration was improved about 23%, which was considered to be caused by defect dispersion effect, while MOE of glulams with these two types of configurations were similar. Because MOE of plywood is generally smaller than that of solid wood laminar, MOE of type BVH glulam decreased about 15%, but in the case of type BVV glulam, MOE was improved without any reduction of MOE. The reason of this result could be undersood in the view of shear-reinforcement effect, which was verified from analysis of fracture mode. From the results of this study, it was concluded that bending capacity of glulam could be improved by proper section design, such as laminar arrangement and shear reinforcement.

편측안면경련 환자에서의 임상적 중증도를 평가하기 위한 전기생리학적 연구

전성만,김종국,정재익,차재관,김상호,김재우 대한신경과학회 1998 대한신경과학회지 Vol.16 No.2

서울의 Penicillinase Producing Neisseria gonorrhoeae 발생빈도(1998)

김재홍,김준호,반재용,이정우,황성주,정준규,정성태,강진문,조흔정,홍창의,정혜신,이한승,김이선,이봉길,이종호,선영우,한기덕,윤성필,이성훈,안종성,박석범,문승현,조항래,김형섭,류지호,황재영,박준홍,손상욱 한양대학교 의과대학 2001 한양의대 학술지 Vol.21 No.1

In recent years, gonorrhea has been pandemic and remains one of the most common STDs in the world, especially in developing countries. For the detection of a more effective therapeutic regimen and assessing the prevalence of Penicillinase Producing Neisseria gonorrhoeae(PPNG), we have been trying to study the patients who have visited the Venereal Disease Clinic of Choong-Ku Public Health Center in Seoul since 1980 by menas of the chromogenic cephalosporin method. In 1998, 93 strians of N. genorrhoeae were isolated, among which 60(64.5%) were PPNG. The prevalence of PPNG in Seoul, which had been decreased to 39% in 1996 after a peak of 74.3% in 1993, is increased to 64.5% in 1998.

골프지도자의 변혁적 리더십이 학생골프선수의 교육만족과 기술만족에 미치는 영향

남재준(Nam, Jae-Jun1),김민(Kim, Min) 한국체육과학회 2021 한국체육과학회지 Vol.30 No.4

This study intends to clarify the causal relation that golf instructor’s innovative leadership has on satisfaction in education & satisfaction in technique of middle school & high school student golfers training in golf academy. The purpose is to provide student golfers with basic data which help golf academy instructor improving leadership & which can develop golfers to excellent players. The target of study are 305 student golfers who are training in golf academy after affiliating in Korea Middle School & High School Golf Federation. Data was processed with frequency analysis, exploratory factor analysis(EFA), reliability analysis, correlation analysis, multiple regression analysis by using SPSS 25.0 Window Version. As a result, first, it is found that golf academy instructor’s innovative leadership has significant influence on student golfer’s satisfaction in education. Second, it is found that golf academy instructor’s innovative leadership has significant influence on student golfer’s satisfaction in technique.