• 한국포장학회지
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• 제4권1호
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• pp.17-21
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• 1997

Zeolite powder used by molecular sieve, adsorbants and catalist. 1N HCl teated zeolite powders for freshness extension of fruits and vegetables showed that specific surface area was $300.29m^2/g$ largest then that of the others, and ethylene gas adsorbability was 29.07 cc/g. And then 0.5N NaCl Henting after 1N HCl treated zeolite powder showed that specific surface area and ethylene gas adsorbability was $329.43m^2/g$ and 35.64 cc/g largest then those of the others. Specific surface area of processed zeolite powder treated by high intensity magnetic seperator(HIMS) showed $369.67m^2.g$, ethylene gas adsorbability was 39.87cc/g. In this study, it could be employ 0.5N NaCl treat and HIMS methods as MA packaging materials for freshess extension of fruits and vegetables.

• Journal of Microbiology and Biotechnology
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• 제20권11호
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• pp.1597-1602
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• 2010

Chitinase is one of the most important mycolytic enzymes with industrial significance. This enzyme is produced by a number of organisms including bacteria. In this study, we describe the optimization of media components with increased production of chitinase for the selected bacteria, Stenotrophomonas maltophilia, isolated from soil. Different components of the defined media responsible for influencing chitinase secretion by the bacterial isolate were screened using Plackett-Burman experimental design and were further optimized by Box-Behnken factorial design of response surface methodology in liquid culture. Maximum chitinase production was predicted in medium containing 4.94 g/l chitin, 5.56 g/l maltose, 0.62 g/l yeast extract, 1.33 g/l $KH_2PO_4$, and 0.65 g/l $MgSO_4{\cdot}7H_2O$ using response surface plots and the point prediction tool of the DESIGN EXPERT 7.1.6 (Stat-Ease, USA) software.

• 한국식품영양과학회지
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• 제35권5호
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• pp.649-654
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• 2006

품종별 무청의 표면 미생물 분포와 중심합성계획과 반응 표면분석법을 이용하여 물세척, 마이크로웨이브처리 및 스팀처리를 독립변수로 두고, 이들 전처리 조건에 따른 표면미생물의 변화를 조사하였다. 그 결과 무청 품종에 관계없이 병원성 미생물인 Salmomella spp., Camphylobacter spp., Vibrio spp., Shigella spp., Staphylococcus spp., Enterococcus spp. 및 Pediococcus spp.는 전혀 검출되지 않았다. 그러나 총균수의 경우는 품종에 따라 약간의 차이는 있었는데, $3.90{\times}10^5{\sim}1.20{\times}10^7CFU/g$의 범위를 보였고, 대장균군은 $1.10{\times}10^2{\sim}2.00{\times}10^5CFU/g$, 효모/곰팡이는 $2.40{\times}10^3{\sim}3.55{\times}10^6CFU/g$을 보인 반면 젖산균은 검출되지 않은 시료도 있었다. 또 전처리 방법에 따른 무청의 잔존 미생물의 감균 효과가 가장 좋은 전처리 방법은 스팀처리 방법이었다. 원료 무청의 각각의 전처리 방법을 독립변수(independent variables)로 하고, 총균수, 젖산균수 및 효모/곰팡이균수를 종속변수(dependent variables)로 하여 회귀 분석한 결과 상관관계를 나타내는 $R^2$값이 각각 0.89, 0.87, 0.85로 상관성이 높았으며, 물세척 횟수에 의한 감균 효과는 제한적이므고 마이크로웨이브처리나 스팀처리를 병행하여야 효과적이었다.

• Korean Chemical Engineering Research
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• 제49권2호
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• pp.224-229
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• 2011

본 연구에서 탄성표면파(SH-SAW) 디바이스의 지연선에 코팅된 골드 위에서 면역 글로불린 G(IgG) 검출을 위한 SH-SAW 센서를 개발하고자 하였다. 실험결과, 금표면 위에 anti-MIgG 혼합물을 일관되게 고정시킬 수 있었다. G-anti MIgG 혼합물과 blocking buffer를 이용한 골드 표면 위에 고정화 하였을 때 주파수 변위를 측정한 결과, G-anti MIgG 는 초기 주파수에서 75.1 kHz 주파수 변위를 보였으며 blocking buffer는 215.7 kHz의 주파수 변위를 보였다. 100 MHz 센서에서 MIgG의 농도가 25, 50, 75, 100 ${\mu}g$일 때 46.3, 127.45, 161.21, 262.39 kHz 주파수 변위를 보였다.

• 대한환경공학회지
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• 제31권9호
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• pp.755-764
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• 2009

시화호 인공습지내 표층퇴적토에 의한 오염물질 제거효율을 평가하기 위하여 표층퇴적물내 물질함량과 퇴적토에 의한 오염물질의 용출여부를 조사하였다. 조사기간 동안 표층퇴적물의 COD, TOC, IL, TN, TP 함량은 각각 4.1~47.7 mg/g, 0.29~2.81%, 1.88~8.15%, 0.03~0.35%, 362~1,150 ${\mu}g$/g의 범위로 조사지점과 시기에 따라 차이를 보였다. 유기물과 TN 함량은 봄에 높고 시간이 지날수록 감소하는 경향을 보인 반면 TP 함량은 유의적인 차이를 보이지 않았다(3월${\geq}$5월${\geq}$7월${\geq}$9월, p=0.003 for COD, p=0.001 for TOC, p=0.017 for IL, p=0.015 for TN). 표층퇴적토의 중금속 함량은 As 3.5~13.9 ${\mu}g$/g, Cd 0.08~0.38 ${\mu}g$/g, Cr 51.8~107.0 ${\mu}g$/g, Cu 16.4~81.8 ${\mu}g$/g, Pb 26.8~81.8 ${\mu}g$/g, Zn 85~559 ${\mu}g$/g의 범위로 항목에 따라 상이한 시공간적인 분포를 보였다. 퇴적물환경기준으로 볼 때 유기물 함량은 대부분 기준 이하의 수준을 보인 반면 TN과 TP는 "중간오염" 또는 "심한 오염" 수준을 보였다. 그리고 중금속 함량은 Cd과 Pb을 제외한 모든 항목에서 퇴적물 환경기준으로 초과하는 것으로 나타났다. 퇴적토의 용출실험 결과로부터 TN, Pb, Zn은 퇴적토에 의해 제거되는 반면 TP, Cd, Cu는 퇴적토로부터 용출되는 경향을 보였다. 그러므로 시화호 인공습지에서 표층퇴적토의 수질정화기능을 향상시킬 수 있는 방안수립이 필요하다.

• 공업화학
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• 제35권2호
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• pp.140-147
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• 2024

바이오매스 활용을 높이기 위하여, 열처리 공정을 통해 강아지풀 기반 리튬 이온 이차 전지용 탄소음극재(SV-C)를 제조한 뒤 전기화학적 성능을 고찰하였다. 강아지풀의 열처리 온도가 750 ℃로 낮을 때 낮은 결정성과 높은 비표면적(126 m²/g)과 함께, 표면에 많이 존재하는 산소의 (-) 전하가 리튬을 끌어당김으로 인하여 비정전용량(1003.3 mAh/g, at 0.1 C)이 높지만, 용량 유지율은 61.0% (at 500 cycles and 1 C)로 낮아지는 것으로 여겨진다. 또한, 열처리온도가 1150 ℃로 증가하면 탄소층이 축합되어 배열이 우수해짐에 따라 구조 결함이 감소하여 기공이 크게 줄어 비표면적(32 m²/g)이 감소한 것으로 확인되었다. 또한, 음극재 표면결함이 감소하여 결정성이 높아지게 되면, 용량 유지율은 89.7% (at 500 cycles and 1 C)로 높지만, 결함 정도가 작아 활성점이 줄어들어 비정전용량이 471.7 mAh/g로 매우 낮은 것으로 여겨진다. 본 연구 범위에서, 열처리 온도에 따라 제조된 강아지풀 기반 탄소음극재의 경우, 비표면적에 비해 표면 산소 함량과 결정성 등이 음극재의 전기화학적 특성에 더 높은 신뢰도를 갖는 것으로 나타났다.

• 한국식품조리과학회지
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• 제20권1호
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• pp.112-118
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• 2004

The purpose of this study was to find the optimal mixing conditions of three different amounts of gelatin, green tea powder and sucrose for preparation green tea powder jelly. A central composite design involving gelatin(12 ∼ 16g), green tea powder(3∼5g) and sucrose(40∼60g) was used to investigate the sensory characteristics of green tea powder jelly. Sensory characteristics, such as hardness, elasticity, sweetness, transparency, color, flavor and overall quality of green tea powder jelly, were measured using a response surface methodology computer program. The overall optimal conditions that satisfied all the sensory properties of green tea powder jelly were 13.4g gelatin, 4.2g green tea powder and 50.8g sucrose.

• The Journal of Advanced Prosthodontics
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• 제16권1호
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• pp.25-37
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• 2024

PURPOSE. To investigate the effect of sintering programs and surface treatments on surface properties, phase transformation and flexural strength of monolithic zirconia. MATERIALS AND METHODS. Zirconia specimens were sintered using three distinct sintering programs [classic (C), speed (S), and superspeed (SS)] (n = 56, each). One sample from each group underwent scanning electron microscopy (SEM) and grain size analysis following sintering. Remaining samples were divided into five subgroups (n = 11) based on the surface treatments: control (CL), polish (P), glaze (G), grind + polish (GP), and grind + glaze (GG). One sample from each subgroup underwent SEM analysis. Remaining samples were thermally aged. Monoclinic phase volume, surface roughness, and three-point flexural strength were measured. Monoclinic phase volume and surface roughness were analyzed by Kruskal-Wallis and Dunn tests. Flexural strength was analyzed by two-way ANOVA and Weibull analysis. The relationships among the groups were analyzed using Spearman's correlation analysis. RESULTS. Sintering program, surface treatment, and sintering × surface treatment (P ≤ .010) affected the monoclinic phase volume, whereas the type of surface treatment and sintering × surface treatment affected the surface roughness (P < .001). Type of sintering program or surface treatment did not affect the flexural strength. Weibull analysis revealed no significant differences between the m and σ_o values. Monoclinic phase volume was positively correlated with surface roughness in the SGG and SSP groups. CONCLUSION. After sintering monolithic zirconia in each of the three sintering programs, each of the surface treatments can be used. However, for surface quality and aging resistance, G or GG can be recommended as a surface finishing method.

• 상하수도학회지
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• 제23권1호
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• pp.113-119
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• 2009

The feasibility of using cork oak bark for phosphorus removal from wastewater was evaluated in this study. Recently, development of more cost-effective media while maintaining high efficiency in pollutants removal has received concern. Barks have a negative surface charge and, hence, tend to show a high affinity to bind cations, and they need to undergo chemical modification to increase their adsorption capacity of anions. Bark was hydrolyzed by HCl solution and it received modification using an aqueous solution of high molecular weight polyethylenimine(PEI). Surface modification with HCl and PEI resulted in a decrease of specific surface area of the bark from $1.932 m^2/g$ to $1.094 m^2/g$. The adsorption experiments were carried out in batch tests and the data were fitted to the Langmuir isotherm and Freundlich isotherm equations. Phosphate removal rate was higher at the lower solution pH possibly due to the form of phosphate ion in solution. For the initial phosphate concentration of 10 mg/L, maximum adsorption was 20.88 mg P/g at pH 3 and 12.02 mg P/g at pH 5. Mechanism of phosphorus sorption onto the HCl-PEI bark was examined through FT-IR spectrometer. Ion exchange between $NH^+$ and $H_2PO_4{^-}$ appeared to be a key mechanism of phosphate adsorption onto the HCl-PEI bark surface.

• 한국환경과학회지
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• 제9권2호
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• pp.137-144
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• 2000

The observations on the seasonal fluctuation and distributional characteristic of organic matters on surface sediments and its origin were carried out at the 25 stations in Keogeum-sudo, southern coast of Korean Peninsula from February to October in 1993. I made an analysis on the environmental factors for surface sediments such as temperature, ignition loss, chemical oxygen demand, pheopigment, total sulphide, water content, mud content in grain size, COD/IL ratio and COD/sulphide ratio. The results are as follows ; 1) The range of temperature on the surface sediments was between 6.2${\circ}C$ and 24.6${\circ}C$. The highest mean temperatuer of mud was 24.0${\circ}C$ in summer, the lowest 6.6${\circ}C$ in winter. 2) Ignition loss(IL) fluctuated between 1.2% in winter and 16.8% in spring, that is to say, the seasons of increasing in temperature were very high ignition loss. 3) Chemical oxygen demand(COD) showed the highest mean value of 20.52 mg/g dry in summer within the range of 15/46~32.78 mg/g dry, while showed the lowest of 5.79 mg/g dry in winter within the range of 7.4~17.39 mg/g dry. 4) Pheopigment concentrations showed the highest mean value of 4.85 $\mu\textrm{g}$/g dry in autumn within the range of 0.84~9.21 $\mu\textrm{g}$/g dry, while it did the lowest mean value of 1.97 $\mu\textrm{g}$/g dry in summer within the range of 0.23~4.83 $\mu\textrm{g}$/g dry. 5) Total sulphide (H2S) fluctuated between no detect(ND) in spring, and 2.43 mg/g dry in sutumn. The highest mean value was 0.68 mg/g dry in sutumn, the lowest was 0.16 mg/g dry in spring. 6) Water content(WC) and mud content in grain size showed the mean value of 43.2% within the range of 26.5~59.7% and 91.0% within the range of 57.8~99.2%, respectively. 7) By the analytical results on the source of organic matter, it had been dumped from the seaweed farms in Keogeum-sudo coastal waters.