• 한국수산과학회지
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• 제57권1호
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• pp.32-40
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• 2024

The aim of this research was to apply a method designed to derive the factors influencing total ammonia removal when operating an additional pretreatment system at Aquaponics. The Box-Behnken method, among response surface analysis methods was used to characterize and determine the optimal nitrification conditions when operating the pretreatment system. Among the mathematically and statistically calculated prediction equations, the total ammonia nitrogen concentration Y1 measured on day 8 was derived as Y₁=-195.8+2.23X₁+42.9X₂+47.5X₃+0.1856X₁²-1.380X₁X₂-1.770X₁X₃, and the time taken to reach the maximum total ammonia nitrogen concentration during the experiment period was derived as Y₂=271-5.04X₁+60.5X₂-64.8X₃+0.1654X₁²+6.54X₃²-0.600X₁X₃-9.00X₂X₃. The coefficients of determination of the regression models of Y₁ and Y₂ were 93.99% and 94.46%, respectively. The modified coefficients of determination were also high, at 89.48% and 88.91%, respectively. The prediction coefficients of determination of Y₁ and Y₂, were 70.68% and 62.11%, respectively, which was relatively lower than that of Y1, but still indicated a reliable prediction performance.

• 한국약용작물학회지
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• 제26권2호
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• pp.127-133
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• 2018

Background: The demand of recycling renewable agricultural by-products is increasing. Radiation breeding is a method used to improve saccharification efficiency. Thus, we investigated the effect of gamma ray irradiation on the pretreatment and enzymatic hydrolysis of the stalks of Senna tora, an important medicinal plants. Methods and Results: S. tora seeds were irradiated with gamma ray at doses of 100, 200, 300, and 400 Gy. In the pretreated biomass, glucan and lignin content were higher in the M1 ($1^{st}$ generations of irradiation) S. tora stalks than in the M2 ($2^{nd}$ generations of irradiation) stalks, this can be explained by the higher degradation rate in M1. After oxalic acid pretreatment, the concentration of total phenolic compounds (TPCs) in the hydrolysate increased in the gamma ray treated seeds. The highest relative increase rate in crystallinity in the pretreated biomass was observed in M1-400 Gy and M2-100 Gy. The cellulose conversion rate was higher in M1 than in M2, except for 200 Gy. Conclusions: Gamma ray irradiation at an appropriate dose can be used to improve the efficiency of pretreatment and enzymatic hydrolysis, thereby increasing biomass availability.

• Environmental Engineering Research
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• 제20권3호
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• pp.223-229
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• 2015

The application of coagulation for feed water pretreatment prior to microfiltration (MF) process has been widely adopted to alleviate fouling due to particles and organic matters in feed water. However, the efficiency of coagulation pretreatment for MF is sensitive to its operation conditions such as pH and coagulant dose. Moreover, the optimum coagulation condition for MF process is different from that for rapid sand filtration in conventional drinking water treatment. In this study, the use of response surface methodology (RSM) was attempted to determine coagulation conditions optimized for pretreatment of MF. The center-united experimental design was used to quantify the effects of coagulant dose and pH on the control of fouling control as well as the removal organic matters. A MF membrane (SDI Samsung, Korea) made of polyvinylidene fluoride (PVDF) was used for the filtration experiments. Poly aluminum chloride (PAC) was used as the coagulant and a series of jar tests were conducted under various conditions. The flux was $90L/m^2-h$ and the fouling rate were calculated in each condition. As a result of this study, an empirical model was derived to explore the optimized conditions for coagulant dose and pH for minimization of the fouling rate. This model also allowed the prediction of the efficiency of the coagulation efficiency. The experimental results were in good agreement with the predictions, suggesting that RSM has potential as a practical method for modeling the coagulation pretreatment for MF.

• 공업화학
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• 제18권6호
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• pp.552-556
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• 2007

연구에서는 $TiO_2$ 담체에 귀금속(Pd, Ru, Ir)을 담지시켜 촉매를 제조하였다. 금속분산의 향상을 위해 $H_2O-H_2$ 전처리 기술이 이용되었고, 반응물로서 xylene, toluene 그리고 MEK를 사용하였다. 단일금속과 합금금속의 촉매들은 함침법에 의해 준비하였고, XRD, XPS 분석을 통하여 특성 분석하였다. Pd-Ru, Pd-Ir 촉매는 다양한 활성점을 나타내었고, 그것은 Pd의 metal 영역를 강화시켰다. 합금금속으로 이루어진 촉매가 단일 금속으로 이루어진 촉매에 비해 VOCs 전환율이 더 높았다. $H_2O-H_2$ 전처리 기술은 Pd 입자를 고르게 분산시켰다. 이는 촉매의 효율을 증진시키는 효과를 보여주었다. 본 연구에서 Pd에 소량의 Ru, Ir 첨가는 VOCs의 산화반응을 증진시켰고, $TiO_2$ 담체상에서 $H_2O-H_2$ 전처리는 VOCs의 제거효율을 증진시켰다.

• Restorative Dentistry and Endodontics
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• 제39권3호
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• pp.180-186
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• 2014

Objectives: The purpose of this in vitro study was to evaluate the microleakage and penetration of fissure sealant in permanent molar teeth with fluorosis after pretreatment of the occlusal surface. Materials and Methods: A total of 120 third molars with mild dental fluorosis were randomly divided into 6 groups (n = 20). The tooth surfaces were sealed with an unfilled resin fissure sealant (FS) material. The experimental groups included: 1) phosphoric acid etching (AE) + FS (control); 2) AE + One-Step Plus (OS, Bisco) + FS; 3) bur + AE + FS; 4) bur + AE + OS + FS; 5) Er:YAG laser + AE + FS; and 6) Er:YAG laser + AE + OS + FS. After thermocycling, the teeth were immersed in 0.5% fuchsin and sectioned. Proportions of mircoleakage (PM) and unfilled area (PUA) were measured by digital microscope. Results: Overall, there were significant differences among all groups in the PM (p = 0.00). Group 3 showed the greatest PM, and was significantly different from groups 2 to 6 (p < 0.05). Group 6 showed the lowest PM. Pretreatment with Er:YAG with or without adhesive led to less PM than bur pretreatment. There were no significant differences among groups in PUA. Conclusions: Conventional acid etching provided a similar degree of occlusal seal in teeth with fluorosis compared to those pretreated with a bur or Er:YAG laser. Pretreatment of pits and fissures with Er:YAG in teeth with fluorosis may be an alternative method before fissure sealant application.

• Journal of Pharmaceutical Investigation
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• 제27권2호
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• pp.109-117
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• 1997

In order to elucidate the effect of phenobarbital (PB) on the nonlinear pharmacokinetic behavior of naproxen (NAP), we compared the dose dependent hepatic intrinsic clearance, biliary excretion and protein binding of NAP in control rats to those in the PB-pretreated rats which were intraperitoneally pretreated with PB sodium (75 mg/kg) once a day for four days. NAP was injected via femoral (1.5 mg/kg) and portal(0.25, 0.5, 1.5, 15 and 30 mg/kg) vein to the control and PB-pretreated rats, respectively. And also, we measured the plasma free fraction of NAP with the equilibrium dialysis method and the biliary excreted total amounts of NAP in both rats. Plasma free fraction of NAP was decreased in lower concentration than $150\;{\mu}g/ml$ of NAP due to PB pretreatment. In higher concentration, however, plasma free fraction was increased. These in vitro results suggest that the total protein concentration was increased but the total binding capacity of NAP to protein was decreased by PB-pretreatment. The total plasma clearance and the hepatic intrinsic clearance of NAP had similar values in both groups, respectively. And, both clearances of NAP were significantly increased by PB-pretreatment. Even though the plasma free fractions of NAP in both groups were constantly remained within the concentration range according to the increase of administration dose, the hepatic intrinsic clearances of NAP were significantly increased in both groups with the increased dose. And, the biliary excreted total amounts of NAP were significantly increased by PB-pretreatment at the lower dose, but decreased at the higher dose. These in vivo results suggest that NAP represents the uncommon nonlinear pharmacokinetic behavior that the hepatic intrinsic clearance was enhanced with the increased dose, and that PB enhances further the hepatic intrinsic clearance of NAP with the increased dose due to its enzyme induction effect.

• 한국식생활문화학회지
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• 제15권2호
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• pp.95-100
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• 2000

This study was attempt to improve the quality of rapid- and low salt-fermented liquefaction of sardine (Sardinops melanoslicta). Effect of pretreatment methods such as water adding, heating, and intermittent NaCl adding on fermented liquefaction of chopped whole sardine were investigated. The divisions of the experimental samples by pretreatment methods were as follows; Sample A (water adding and heating): chopped whole sardine adding 20% water and then adding 3 and 5% NaCl consecutively at the intervals of 3 and 6 hrs during heating for 9 hrs at $50^{\circ}C$ and then fermented at $33^{\circ}C$ for 90 days. Sample B (preheating): chopped whole sardine with 8% NaCl and heating at $50^{\circ}C$ for 9 hrs and then fermented at $33^{\circ}C$ for 90 days. Sample C (control): neither pretreatment methods of water adding nor preheating on chopped whole sardine with 13% NaCl and then fermented at $33^{\circ}C$ for 90 days. Comparison of the appropriate fermentation period, yield of hydrolysate, chemical composition of fermented liquefied products were carried out. The highest content of amino nitrogen appeared at 60 days in the sample A, 75 days in the sample B, and 90 days in the sample C during the fermentation period. The appropriate fermentation period of the sample A was shorten 15 days than the sample B and 30 days than the sample C in the processing of sardine. The product A was lower NaCl (8.5%) and lower histamine content (25mg/100g) than the sample B and C. Possibly, three kinds of pretreatment methods such as water adding, heating, and intermittent NaCl adding, might be recommend as the processing of rapid- and low salt-fermented liquefaction product of chopped whole sardine.

• 대한화학회지
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• 제43권4호
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• pp.412-417
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• 1999

실리콘 웨이퍼 중의 금속 불순물을 유도결합플라스마-질량분석기(ICP-MS)로 분석하기 위한 시료의 전처리 방법으로 마이크로파 분해법과 산분해법을 비교하였다 $HNO_3$-HF 혼합용액을 실리콘 웨이퍼 시료에 가하고 마이크로파 분해법과 산분해법으로 용해시킨 후, 용액의 실리콘 매트릭스는 증발 용기 안에서 Si-F의 형태로 증발시켜 분석하였다. 실제 시료에 spike한 Ni, Cr 및 Fe의 회수율은 두 전처리 방법에서 95∼106%였다. Cu의 경우는 산분해법이 회수율이 더 좋았고, Zn의 경우는 마이크로파 분해법으로 전처리 한 경우의 회수율이 더 좋았다. Spin coater로 Fe를 오염시킨 실리콘 웨이퍼를 산분해법과 마이크로파 분해법으로 전처리하여 ICP-MS로 분석한 결과, Fe의 농도는 위의 두 전처리 방법에서 거의 차이가 없었다.

• 한국습지학회지
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• 제24권2호
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• pp.83-92
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• 2022

전세계적으로 플라스틱에 대한 수요가 늘어감에 따라 플라스틱 폐기물의 양이 증가하고 있다. 수계 내에서의 미세플라스틱의 위해성에 대한 평가 기준에 대해서는 아직 많은 연구가 필요하지만 대체적으로 미세플라스틱을 성질 개선을 위해 첨가하는 화학물이 유독하다는 사실은 여러 문헌을 통해 증명되어있다. 하수처리장(MWTP)은 오수를 처리하는 시설로서 가정에서 발생하는 미세플라스틱이 모이는 미세플라스틱이 모이는 장소이다. 따라서 MWTP 에서의 미세플라스틱 분석이 필요한 상황이지만 이를 진행하기 위해 표준화된 방법이 아직은 없다. 따라서 본 연구에서는 MWTP에서 미세플라스틱 검출을 위한 하수 시료에 적용할 수 있는 최적의 방법론을 조사해보고자 한다. 본 연구에서는 J 하수 처리장에서 수집한 유입수 샘플로부터 미세플라스틱을 분석하는 다양한 전처리 방법 중에서 하수처리장 샘플에 가장 널리 사용되는 펜톤산화와 H₂O₂ 산화법을 선정하였다. 각 전처리 방법별로 측정에 오차를 발생시킬 요소들이 있었으며, 이를 극복하기 위해 펜톤산화 전처리의 경우 밀도분리법 대신 여과를 진행하여 분석을 진행하는 것이 추천되며, H₂O₂ 산화법의 경우 반응 이후 증류수로 세척하는 과정이 필요해 보인다. 분석 결과 미세플라스틱의 농도는 H₂O₂ 산화법을 이용한 샘플의 경우 2.75 ea/L, 펜톤산화법을 이용한 샘플의 경우 3.2 ea/L 로 측정되었으며 대부분 섬유형태로 존재하였다. 또한 정량분석을 현미경을 이용해 육안으로 진행하기 때문에 측정 결과에 대한 신뢰성을 보장하기가 어렵다고 판단해 검정곡선을 만들었다. 총 3개의 검정곡선이 그려졌으며 해당 검정곡선들을 분석한 결과 R² 값이 전부 0.9 이상이였으며 이는 정량분석에 대해 높은 신뢰성을 보장한다. 정성분석으로 MWTP에 유입되는 미세플라스틱의 계열에 대해선 판단할 수 있었지만 각 미세플라스틱의 화학적인 조성에 대해선 확인할 수 없었다. 향후 MWTP에 유입되는 미세플라스틱의 화학적 조성에 대해서 확인하기 위해서 이번 연구를 활용할 수 있을 것이다.

• 한국환경보건학회지
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• 제16권2호
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• pp.113-119
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• 1990

Many studies on the analysis of cations in blood have been reported. However, no suitable method for the pretreatment of blood for the determination of cations by Ion Chromotography. As a result, pretreatment method that the membrane filtration of plasma a diluted 1 to 100 fold acidified pH 3.5 was found to be the most suitable. The recoveris of monovalent cations in blood were yield 101%(Na$^{+}$). 102%(NH$^{+}_{4}$) and 101%(K$^{+}$) Determinations of divalent cations(Mg and Ca ions) in blood by Ion chromatography were summarized as followed conditions Separator Column : CS$_{3}$. Suppressor Column : CMMS. Eluent conen : 25m M-HCl/2mM-Histidine. Regenerant conen: 40mM-Ba(OH)$_{2}$.