• 한국식품과학회지
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• 제37권2호
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• pp.287-293
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• 2005

본 연구는 서부경남 진주지역 생딸기 주스 상점에서 미생물학적 오염도를 조사하고 그 결과를 주스 HACCP 도입을 위한 미생물학적 정보를 제공하기 위하여 수행하였다. 본 연구를 위하여 총 75점의 시료를 5곳의 상점으로부터 채취하였으며, 일반세균수, coliforms, 그리고 E. coli와 같은 위생지표세균을 평가하였다. 아울러 E. coli O157:H7, Salmonella spp., Staphylococus aureus and Listeia monocytogenes와 같은 병원성 미생물을 검사하였다. 위생지표세균 검사결과 일반세균수는 $0-5.2\;log_{10}\;CFU/(mL,\;g,\;100cm^{2},\;hand)$. coliform은 $0-2.8\;log_{10}\;CFU/(mL,\;g,\;100cm^{2},\;hand)$ 수준으로 검출되었다. 또한 4곳의 상점에서 판매되고 있는 딸기 주스에서 E. coli가 검출되었다. 한편, 병원성 미생물의 경우는 S. aureus가 19% 검출되었으며 특히 가장 빈번하게 검출된 시료는 작업자의 손, 딸기, 딸기 주스였다. 그러나 E. coli O157:H7, Salmonella spp.와 L. monocytogenes는 검출되지 않았다. 이상의 결과로 미루어 볼 때 안전한 주스의 생산을 위해서는 모든 생산단계에서 미생물학적 위해를 감소시킬 수 있는 HACCP 제도가 도입되어야 하며 주스 HACCP 도입을 위해서는 작업자가 HACCP의 원리를 이해하고 적용할 수 있는 교육이 선행되어야 할 것으로 사료된다.

• 한국식품과학회지
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• 제36권3호
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• pp.514-517
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• 2004

본 연구에서는 이산화염소 처리를 이용하여 대표적 식중독 미생물인 E. coli O157:H7, Salmonella typhimurium, Listeria monocytogenes에 대한 살균 효과를 측정하였다. Pure cell culture 상태에서의 E. coli는 이산화염소 5 ppm에서 D-value가 3.37분으로 측정되었다. 그러나 Salmonella와 Listeria의 생존곡선은 이산화염소 처리시간에 따라 biphasic curve를 나타내었다. 이러한 biphasic curve는 5분까지의 처리로 해당 농도에서의 살균효과는 대부분 나타나고 그 이후는 효과가 없음을 보여주었다. 특히 Listeria의 5ppm과 10ppm의 처리결과는 이산화염소의 처리에 영향을 주는 인자 중 처리 시간보다는 처리농도가 더 큰 영향을 끼치는 것을 나타내었다. 본 연구 결과는 이산화염소 허용치인 5ppm이 신선채소에 대한 미생물학적 안전성을 확보 하기엔 부족하다는 것을 시사한다.

• E2M - 전기 전자와 첨단 소재
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• 제16권9호
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• pp.63.2-64
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• 2003

Epitaxial yttrium-stabilized HfO$_2$ thin films were deposited on p-type (100) Si substrates by pulsed laser deposition at a relatively lower substrate temperature of 550. Transmission electron microscopy observation revealed a fixed orientation relationship between the epitaxial film and Si; that is, (100)Si.(100)HfO$_2$ and [001]Si/[001]HfO$_2$. The film/Si interface is not atomically flat, suggesting possible interfacial reaction and diffusion, X-ray photoelectron spectrum analysis also revealed the interfacial reaction and diffusion evidenced by Hf silicate and Hf-Si bond formation at the interface. The epitaxial growth of the yttrium stabilized HfO$_2$ thin film on bare Si is via a direct growth mechanism without involoving the reaction between Hf atoms and SiO$_2$ layer. High-frequency capacitance-voltage measurement on an as-grown 40-A yttrium-stabilized HfO$_2$ epitaxial film yielded an dielectric constant of about 14 and equivalent oxide thickness to SiO$_2$ of 12 A. The leakage current density is 7.0${\times}$ 10e-2 A/$\textrm{cm}^2$ at 1V gate bias voltage.

• Journal of Applied Biological Chemistry
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• 제62권1호
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• pp.7-10
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• 2019

꼬리겨우살이(Loranthus tanakae) 전초를 80% MeOH 수용액으로 4회 반복 추출한 뒤, 감압 농축한 추출물을 ethyl acetate(EtOAc), n-butyl alcohol (n-BuOH)과 $H_2O$층으로 계통 분획을 실시하였다. n-BuOH 분획에 대하여 silica gel ($SiO_2$), octadecyl silica gel (ODS), Sephadex LH-20 column chromatographies를 반복실시하여 1종의 cyclofarnesane sesquiterpene glucoside 화합물을 분리 및 정제하였다. 스펙트럼 데이터를 분석하여 입체 구조를 포함한 화합물의 구조를 (1'R,3'S,5'R,8'S,2E,4E)-dihydrophaseic acid $3^{\prime}-O-{\beta}-{\text\tiny{D}}$-glucopyranoside로 구조동정 하였다. 이 화합물은 이번 실험을 통하여 꼬리겨우살이로 부터는 최초로 분리되었다. 분리한 단일 물질은 AGS (Caucasian gastric adenocarcinoma cells)와 Hepatocyte carcinoma cells에 대하여 $50{\mu}g/mL$ 이상에서 농도 의존적으로 유의한 정도의 세포독성을 보이는 것이 확인되었다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(2)
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• pp.197-200
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• 2001

Novel Enhanced Inductively Coupled Plasma is applied to etch $SiO_2$. Effect of $O_2$ or Ar addition to $C_{4}F_{8}$ gas is monitored by Optical Emission Spectroscopy and Quadrupole Mass Spectrometer. It is fund that Ar or $O_2$ dilution to $C_{4}F_{8}$ increases F emission intensity and decreases $CF_2$ intensity. However, the ac frequency to the Helmholtz coil decreases the F intensity and thus increases $CF_2$/F ratio. By adjusting the ac frequency, the optimum etch rate and PR to $SiO_2$ selectivity can be obtained in E-lCP.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.489-494
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• 2001

In this thesis, the microstructure and electrical properties of ZnO varistors were investigated according to ZnO varistors with various formulation. A∼E's ZnO varistor ceramics were exhibited good density, 95% of theory density and low porosity, 5%, wholly. The average grain size of A-E's ZnO varistor ceramics exhibited 11.89$\mu\textrm{m}$, 13.57$\mu\textrm{m}$, 15.44$\mu\textrm{m}$, 11.92$\mu\textrm{m}$, 12.47$\mu\textrm{m}$, respectively. Grain size of C's ZnO varistor is larger and grain size of A and D's are smaller than other varistors. In the microstructure, A∼E's ZnO varistor ceramics sintered at l130$^{\circ}C$ was consisted of ZnO grain(ZnO), spinel phase(Zn$\sub$2.33/Sb$\sub$0.67/O$_4$), Bi-rich Phase(Bi$_2$O$_3$) and inergranular phase, wholly. Reference voltage of A∼E's ZnO varistor sintered at 1130$^{\circ}C$ decreased in order D, E > A > B > C's ZnO varistors. Nonlinear exponent of varistors exhibited high characteristics, above 30, wholly. Consequently, C's ZnO varistor exhibited good nonlinear exponent, 68. Lightning impulse residual voltage of A, B, C and E's ZnO varistors suited standard characteristics, below 12kV at current of 5kA.

• 대한수학회지
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• 제45권1호
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• pp.177-196
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• 2008

Using the results on the coefficients of Hermite-Fej$\acute{e}$r interpolations in [5], we investigate convergence of Hermite and Hermite-$Fej{\acute{e}}r$ interpolation of order m, m=1,2,... in $L_p(0<p<{\infty})$ and associated product quadrature rules for a class of fast decaying even $Erd{\H{o}}s$ weights on the real line.

• 한국환경보건학회지
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• 제19권2호
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• pp.61-68
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• 1993

This study aimed at evaluating the preventive effect of Glycyrrhizae Radix and Glycine Semen Extract (GGE) against NAC intoxication. NAC is widely used pesticide in many countries and derivative of carbamats and GGE is well-known antidote to some kinds of toxicants which was referenced from oriental medicine text. The results obtained were as follows: 1) After injecting NAC (100,140 mg/kg), determined Ch.E activities decrease 44.77~50.86% for all experimental groups at one hour after exposure, and were gradually recovered in the course of time. 2) In toxicity test of GGE, there were no sign of death or poisoning up to 5000 mg/kg of GGE for p.o. in mice. From this, we suggest that the LD$_{50}$ of GGE would be above 5000 mg/kg. 3) The Ch.E activity in control group was 471.43 $\pm$ 4.85 luff, group I was 215.27 $\pm$ 23.13 IU/l, group II and group III were 304.03 $\pm$ 9.03 IU/l, 433.81 $\pm$ 21.73 IU/l, respectively. Compare to the control group with experimental group I, remarkable difference revealed (p< 0.01), but the Ch.E activities of group II and III were similar to those of control group. This is indicate that GGE possess a potent activity of recovering Ch.E. GGE had a very remarkable preventive effect on NAC toxicity, and it was able to know that Ch.E activity dramatically increased according to GGE dosage increasing. 4) When GGE and NAC were administered by p.o. simultaneously, LD$_{50}$ and confidence intervals of each group were as follows: the control group: 270 mg/kg, 234.99~310.23 mg/kg, group I and II (GGE 500 mg/kg, 1000 mg/kg by p.o.): 310 mg/kg, 271.69~353.71mg/kg, and 325 mg/kg, 285.09~370.50 mg/kg, respectively. In the comparison with the control group, the protective index was 1.1 and 1.2, respectively. From the above result, GGE has reactivation effect to decreasing Ch.E activity induced by exposure to NAC. Furthermore, GGE shows a preventive effect on NAC intoxication.

• The Journal of Advanced Prosthodontics
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• 제11권4호
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• pp.193-201
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• 2019

PURPOSE. The aim of the present study was to evaluate the color changes of an autopolymerizing PMMA resin used for interim fixed restorations, reinforced with $SiO_2$ nanoparticles. MATERIALS AND METHODS. Silica nanoparticles were blended with the PMMA resin powder through high-energy ball milling. Four shades of PMMA resin were used (A3, B3, C3, D3) and total color differences were calculated through the equations ${\Delta}E_{ab}=[({\Delta}L*)^2+({\Delta}a*)^2+({\Delta}b*)^2]^{1/2}$ and ${\Delta}E_{00}=[(\frac{{\Delta}L^{\prime}}{K_LS_L})^2+(\frac{{\Delta}C^{\prime}}{K_CS_C})^2+(\frac{{\Delta}H^{\prime}}{K_HS_H})^2+R_T(\frac{{\Delta}C^{\prime}}{K_CS_C})(\frac{{\Delta}H^{\prime}}{K_HS_H})]^{1/2}$. Statistically significant differences between ${\Delta}E_{ab}$ and the clinically acceptable values of 3.3 and 2.7 and those between ${\Delta}E_{00}$ and the clinically acceptable value of 1.8 were evaluated with one sample t-test (P<.05). Differences among the different shades were assessed through One-Way ANOVA and Bonferroni multiple comparison tests. RESULTS. Significantly lower values were detected for all groups concerning ${\Delta}E_{ab}$ compared to the intraorally clinical acceptable values of 3.3 and 2.7. Significantly lower mean values were detected for groups B3, C3, and D3, concerning ${\Delta}E_{00}$ compared to the intraorally clinical acceptant value of 1.8. Color pigments in red-brown (A3) and red-grey (D3) shades affect the total color change to a greater extent after the reinforcement with $SiO_2$ nanoparticles compared to the red-yellow (B3) shade. CONCLUSION. Within the limitations of this in vitro study, it can be suggested that reinforcing PMMA with $SiO_2$ nanoparticles at 0.25 wt% slightly affects the optical properties of the PMMA resin without being clinically perceivable.

• 한국세라믹학회지
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• 제55권2호
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• pp.135-139
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• 2018

The glass structure and antibacterial properties of $(65-x)ZnO-xB_2O_3-35P_2O_5$ glasses were investigated. Zinc borophosphate glasses were prepared using a conventional melt-quenching technique at $1000^{\circ}C$. Glass transition temperature and CTE were studied and the structure of zinc borophosphate glasses was evaluated by FTIR. The $Zn^{2+}$ state increase with increasing ZnO content was investigated by XPS and a single sharp Zn $2P_{3/2}$ peak was confirmed, showing that Zn $2P_{3/2}$ exists as $Zn^{2+}$. In order to to evaluate the antimicrobial activity, Escherichia coli (E. coli) was used following the Japanese Industrial Standard JIS Z 2801; the E. coli death rate was found to increase with increasing $Zn^{2+}$ content of glasses.