• The Journal of the Korean Society for Microbiology
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• v.17 no.1
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• pp.1-6
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• 1982

To investigate the annual distribution of hepatitis B surface antigen(HBs Ag) in healthy adults, this study was performed by means of counter-immunoelectrophoresis with sera obtained from 4,856 healthy adults who reside in Seoul and Gyunggi-Do area from January to December, 1981. The experimental procedures were same with the previous reports. The subjectives were consisted of two groups: one is mass life group(3.853 adults) and the other, home life group(1.003 adults). The results were as follows: 1. Among the 4.856 cases tested, 326 cases(6.71%) showed HBs Ag positive. HBs Ag positive rates in the group of mass life and home life were 6.51% and 7.48%, respectively. 2. It showed slightly high positive rates in the home life and long term duration group, and upper class group showed slightly high positive rate. 3. In seasonal variation, it showed relatively high positive rate(7.38%) in winter, and A blood group showed higher rate(7.60%) than the other blood groups. And then, boundary area of Seoul city showed slightly high positive rate(7.36%) in areal distribution.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.597-600
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• 2003

Bi-2223/Ag HTS wires have been fabricated by the PIT(powder in tube)process. Intermediate annealing was carried out to increase the homogenization and uniformity of the superconducting filaments embedded in the silver matrix during the deformation process that is important to sustain the engineering critical current density in long superconducting wire. Intermediate annealing act to release the deformation hardening of the superconducting wires during drawing process. Rolling parameters were investigated to roll the superconducting tapes with uniform thickness, width and winding tensions. Critical current of 60 m long superconducting tapes was measured 54.3 A continuously after final sintering heat treatment. The phase analysis of Bi-2223/Ag superconducting tapes are examined by the XRD.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.04b
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• pp.22-23
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• 2008

본 연구에서는 전면 유기 발광소자(TE-OLED)를 제작하여 전기 광학적 특성을 연구하였다. 전면 발광 OLED의 투명 전극으로 사용된 Al과 Ag의 박막 두께에 따른 투과율과 면저항값은 다음과 같이 나타났다. 파장 520nm의 기준으로 Al 금속 박막의 두께가 10nm 이하여야 50% 투과율을 보였고, 반면 Ag는 25nm 이하로 나타났다. 면저항값은 박막두께 20nm 기준으로 Al은 약 $40\Omega/\square$, Ag는 $10\Omega/\square$이하로 나타났다. 전면발광 방식의 시야각에 따른 빛의 세기는 cos $60^{\circ}$ 일 때 0.1로, TE-OLED는 시야각이 증가하였을 때 현저히 감소되는 것을 볼 수 있다. TE-OLED의 시야각의 증가에 따른 EL-peak 또한 약 520nm의 파장대에서 약 500nm으로 변화하였다. 전면 발광 방식의 반폭치(FWHM)는 배면 발광 방식 보다 약 32nm정도 좁게 나타났다.

• Mycobiology
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• v.37 no.2
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• pp.114-120
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• 2009

Streptomyces albidoflavus C247 was isolated from the soil of the Gyeongsan golf course in Korea. Physiological, biochemical and 16S rDNA gene sequence analysis strongly suggested that the isolate belonged to Streptomyces albidoflavus. Preliminary screening revealed that the isolate was active against fungi and bacteria. Self-directing optimization was employed to determine the best combination of parameters such as carbon and nitrogen source, pH and temperature. Nutritional and culture conditions for the production of antibiotics by this organism under shake-flask conditions were also optimized. Maltose (5%) and soytone (5%) were found to be the best carbon and nitrogen sources for the production of antibiotics by S. albidoflavus C247. Additionally, 62.89% mycelial growth inhibition was achieved when the organism was cultured at $30^{\circ}C$ and pH 6.5. Ethyl acetate (EtOAc) was the best extraction solvent for the isolation of the antibiotics, and 100 ${mu}$/ml of EtOAc extract was found to inhibit 60.27% of the mycelial growth of Rhizoctonia solani AG2-2(IV) when the poison plate diffusion method was conducted.

• Korean Journal of Clinical Laboratory Science
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• v.42 no.1
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• pp.32-37
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• 2010

The author was performed to investigation of current status of prevalence for anti-hepatitis C virus (HCV) among the health-checkup adults in Jeonbuk province. A toal of 1,553 (male 1,046, female 507) serum samples were diagnosed by 3rd generation enzyme immunoassay (EIA) for anti-HCV. Total prevalence of anti-HCV was 0.9%, and prevalence of male and female were 0.8% and 1.2%, respectively. The prevalence of female was higher than male. According to ages group, prevalence of anti-HCV was highest in 60 age group, but it was not found in 20 age group. 14 samples with anti-HCV positive were diagnosed by EIA for hepatitis B virus surface antigen (HBs Ag), by chemiluminescence immunoassay (CLIA) for serum albumin, alanine transaminase (ALT) and asparagine transaminase (AST). Positive for HBs Ag was not found. The mean of serum albumin levels was 4.5 g/dL, and mean of ALT and AST were 34.3 IU and 31.9 IU, respectively. Through this study, I know that the prevalence of anti-HCV among adults in Jeonbuk, and suggest that the positive of anti-HCV persons who have lower serum albumin, normal to mild elevations in serum enzymes are chronic hepatitis.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.6
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• pp.575-579
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• 2004

Package reliability test was conducted to investigate the effect of solder paste composition at BGA Package. It was found that the shape and size of the phase form are affected by the processing parameters. The material have used to fill in the via was Sn/36Pb/2Ag and Sn/0.75Cu type solder paste. Sn/36Pb/2Ag and Sn/0.75Cu paste were fabricated on Tape-BGA substrates by screen printing process, and via ball mount data were characterized with variations of dwell time of 85 seconds at reflow peak temperature at 22$0^{\circ}C$ or 24$0^{\circ}C$. The test condition was MRT 30 $^{\circ}C$/60 %RH/96 HR. Failures formed of a ball-off in solder paste process were observed by using a Optical Microscope and SEM(Scanning Electron Microscope). It was concluded that intermetallic layer growth played important roles in increasing solder fatigue strength for addition of Ag composition. The degradation of shear strength of solder composition is discussed.

• Journal of Technologic Dentistry
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• v.45 no.3
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• pp.55-60
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• 2023

Purpose: This study aimed to evaluate the effects of a special heat treatment on Pd-Au-Ag metal-ceramic alloy after degassing treatment and on changes in the hardness of the alloy during the firing process. Methods: Specimen alloys were cast and subjected to degassing at 900℃ for 10 minutes. These specimens were then subjected to a special heat treatment at 600℃ for 15 minutes in a dental porcelain furnace. Further, the specimens were subjected to simulated firing in the porcelain furnace. The resulting specimens were then tested for hardness, and changes in the microstructure were observed. Results: There was a decrease in the hardness of the alloy during the simulated firing of the cast alloy due to the coarsening of the particles. Meanwhile, additional heat treatment after degassing was found to play a crucial role in preventing a decrease in hardness. This treatment effectively suppressed the coarsening of the precipitates during repeated firing at high temperatures. Conclusion: Specific heat treatment of the Pd-Au-Ag metal-ceramic alloy prevented a decrease in its hardness and extended the lifespan of the metal-ceramic prosthesis.

• Elastomers and Composites
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• v.54 no.3
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• pp.252-256
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• 2019

Fullerene oxide[$C_{60}(O)_n$, ($n{\geq}1$)] was synthesized by dissolving fullerene[$C_{60}$] and 3-chloroperoxybenzoic acid in toluene under refluxing condition for 5 h. Hybrid fullerene oxide-silver nanoparticle composites were synthesized by dissolving fullerene oxide and silver nitrate[$AgNO_3$] in diethylene glycol under ultrasonic irradiation for 3 h. The synthesized hybrid nanocomposites were characterized by X-ray diffraction, scanning electron microscopy, and ultraviolet-visible[UV-vis] spectroscopy. The catalytic activity for the reduction of various nitroanilines[NAs] was identified by UV-vis spectrophotometer. The efficiency of the catalytic reduction by the synthesized hybrid nanocomposites has an order of 4-NA > 2-NA > 3-NA.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.11 no.2
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• pp.130-136
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• 2008

Purpose: Lamivudine is known to be effective for the treatment of chronic hepatitis B in adults. However, data on lamivudine therapy in pediatrics is limited. The aim of this study was to evaluate the efficacy and durability of lamivudine therapy for chronic hepatitis B in Korean children. Methods: A total of 44 children (27 males and 17 females, ages 6 months to 14.8 years, mean age 6.7 years) with chronic hepatitis B who received lamivudine (3 mg/kg/day, max 100 mg) for at least 12 months were enrolled. We evaluated the serum AST, ALT and serological HBV markers (HBsAg and anti-HBs, HBeAg and anti HBe, and HBV DNA) periodically. Predictive three year cumulative seroconversion rates were obtained using the Kaplan-Meier method. Results: Twenty one (48%) of 44 children achieved seroconversion of HBeAg by three years, while 23 (42%) children did not. HBV DNA was cleared in 34 (77%) children and the serum ALT levels were normalized in 41 children (93%). The three year cumulative seroconversion rates were 60% for HBeAg, and the clearance rates were 76% for HBV DNA. Eighteen children who discontinued lamivudine after HBeAg seroconversion maintained the therapeutic response for three years (treatment duration 13~58 months mean 24 months). Viral breakthrough developed in 12 children (27%) during the therapy and the YMDD mutation was documented in 11 children (25%). The mean duration for the development of a mutation was 22.7 months. Loss of HBsAg occurred in 6 children (14%). The pretreatment ALT levels were higher in responders; however, the differences were not statistically significant (p>0.05). Conclusion: The results of this study showed that lamivudine treatment had a favorable effect and durable therapeutic response in children with chronic hepatitis B. Long term follow-up and alternative therapy are warranted for those patients who do not respond to this treatment.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.20-21
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• 2009

우리는 전면 발광 소자에서 두께에 따른 발광 스펙트럼을 연구하였다. 소자 구조는 Al(100nm)/TPD(40nm)/Alq3(60nm)/LiF(0.5nm)/Al(2nm)/Ag(30nm)으로 하였다. N,N'-diphenyl-N,N'-di(m-tolyl)-benzidine(TPD)와 tris-(8-hydroxyquinoline) aluminium(Alq3)는 전공 수송층과 발광층으로 각각 사용되었다. 반투명 전극은 Li/Al/Ag로 하였다. 유기물층과 전극은 $2\times10-5$torr의 진공도에서 열 증착하였다. 유기물과 금속의 증착 속도는 $0.5\sim1.0{\AA}/s$과 $0.5\sim5{\AA}/s$로 하였다. 제작된 소자는 두께가 증가할 수록 장파장으로 이동하는 현상을 보였다. 이러한 현상은 마이크로 캐비티 이론으로 설명할 수 있다. 소자는 이론적인 마이크로 캐비티 수식을 이용하여 분석하기 위해 각각의 변수를 이용하여 실험과 이론을 비교하였을 때, 각각의 스펙트럼이 거의 일치하는 것을 확인할 수 있었다.