• Membrane and Water Treatment
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• 제10권2호
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• pp.127-137
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• 2019

The D2EHPA/TBP co-extractants immobilized PolyHIPE membrane can be used for the selective separation of Mn (II) from Co (II). By solvent-nonsolvent method, D2EHPA/TBP co-extractants can be effectively immobilized into PolyHIPE membrane. The pore structure of PolyHIPE membrane and the presence of TBP enhance the stability of immobilized co-extractants. The optimal operating conditions for the separation of Mn (II) and Co (II) are feeding phase at pH 5.5, sulfuric acid concentration in the stripping phase of about 50 g/L and stirring speed at 400 rpm. The D2EHPA/TBP co-extractants ratio of 5:1 shows synergetic effect on Mn/Co separation factor about 22.74. The removal rate and recovery rate of Mn (II) is about 98.4 and 97.1%, respectively, while for Co (II) the transport efficiency is insignificant. The kinetic study of Mn (II) transport shows that high initial flux, $J_f^o=80.1({\mu}mol/m^2s)$, and maxima stripping flux, $J_s^{max}=20.8({\mu}mol/m^2s)$, can be achieved with D2EHPA/TBP co-extractants immobilized PolyHIPE membrane. The stability and reusability study shows that the membrane can maintain a long term performance with high efficiency. High purity of Co (II) and Mn (II) can be recovered from the feeding phase and stripping phase, respectively.

• Korean Chemical Engineering Research
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• 제60권3호
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• pp.423-432
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• 2022

Magnetic biochar produced from pyrolysis of dairy cattle manure was used to develop an effective sorbent for arsenic purification from aqueous solution. Biomass and magnetized biomass were pyrolyzed in a tube furnace with 10 ℃/min heating rate at 450 ℃ under nitrogen flow of 100 cm³/min for 2 h. Biochars were characterized by SEM-EDX, BET, XDR, FTIR, TGA, zeta potential analysis. The resultant biochar and magnetic biochar were opposed to 50-100-500 ppm As(V) laden aqueous solution. Adsorption experiments were performed by using ASTM 4646-03 batch method. The effects of concentration, pH, temperature and stirring rate on adsorption were evaluated. As(V) was successfully removed from aqueous solution by magnetic biochar due to its highly porous structure, high aromaticity and polarity. The results suggest dairy cattle manure pyrolysis is a promising route for managing animal manure and producing a cost effective biosorbent for efficient immobilization of arsenic in aqueous solutions.

• 한국식품과학회지
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• 제38권6호
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• pp.767-772
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• 2006

유산균의 일종인 Lactobacillus sp.을 중심물질로 하고 그 바깥을 2중층으로 미세캡슐화하는 공정을 위한 최적 조건을 확립하였는데, [중심물질]과 [피복물질]의 혼합비율과 유화제 첨가농도, 2중층 유화계내의 2종류 유화제(PGPR/PSML)에 의한 상승효과, 분산액의 온도 및 분산액의 교반속도가 유산균함유 2중층 미세캡슐화 수율에 미치는 영향을 검토하였다. W/O형 및 W/O/W형 유화계내에서의 중심물질과 피복물질의 혼합비율과 유화제 첨가농도에 다른 최적조건을 탐색한 결과, Lactobacillus sp.(Cm)와 옥배경화유(Wm)와의 혼합비율이 [W/O형 Cm]:[W/O형 Wm]=3:2(w/w), 1.00%의 유화제(PGPR) 첨가농도에서 최대의 수율을 나타내었으며, 유산균을 옥배경화유가 단일층으로 둘러싼 W/O형 유화계와 다당류 호화액의 혼합비율 즉, [W/O/W형 중심물질, CM]:[W/O/W형 피복물질, WM]=1:3(w/w) 0.65%의 유화제(PSML) 농도에서 가장 높은 미세캡슐화 수율을 얻을 수 있은 것으로 판명되었다. 최종적으로, 유산균 2중층 미세캡슐화 공정을 위한 여러 가지 요인들 중 물리적인 조건의 변화를 살펴본 결과, 분산매의 온도가 10$^{\circ}C$이며, 미세캡슐을 함유하는 분산액 제조시의 교반정도가 270rpm일 때 2중 미세캡슐화의 가장 높은 수율을 확인 할 수 있다.

• 한국식품영양과학회지
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• 제19권6호
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• pp.617-624
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• 1990

유과제조에 좋은 특성을 갖는 일반계 찹쌀(품종： 신선)을 이용하여, 유과의 기업적 생산에 필요한 유과의 제조조건 및 팽화기작 추적 시험을 실시하였다. 유과 반데기 제조를 위한 증자시간은 증기가열로 5, 10, 15, 30, 45, 60분 처리에서 15분이 가장 적당하였고. 반죽의 수분함량은 48, 51, 53%를 시험한 결과, 48% 수준에서 조직이 가장 치밀하였다. 꽈리치는 시간은 1, 3, 4분간에 유의적인 차이가 없이 품질이 우수하나. 전혀 꽈리치기를 하지 않은 처리구는 조직의 치밀성이 낮고, 경도가 아주 유약하였다. 습식 및 건식제 분등 제분방법별 고온처리에 의한 공정단순화 시도에서 습식제분이 건식제분보다 팽화율이 높았으나, 고온처리 시간이 길어질수록 팽화율이 낮아졌고, 환원당량도 증가하여 전분의 분해가 이루어짐을 알 수 있었고. 이들이 유과의 팽화에 부정적인 영향을 주었으나. 각종 두류를 첨가한 결과 단백질 함량이 높아짐에 따라 유과특성이 개선되었다. 반데기는 장기저장시 RM에 따라 흡습정도가 달라졌고, 저장기간에 따라 팽화후 유과 바탕의 품질은 열화 되었다. 유과제조시 주류로서 막걸리, 소주, 청주를 각각 다른 양 첨가하여 품질을 비교한 결과, 첨가량이 중량비로 15%에서 30%로 증가함에 따라서 팽화율 및 조직특성이 다소 향상되었다.

• 접착 및 계면
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• 제13권1호
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• pp.17-23
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• 2012

스트레스 완화를 목적으로 향기나는 마이크로캡슐을 제조하여 수험생들을 대상으로 평가하였다. 향 오일로는 긴장완화에 효과가 있다고 알려진 rosmarinic acid를 사용하였으며 벽재 물질로는 polycaprolactone (PCL)을 사용하였고 안정제로는 poly(vinyl alcohol) (PVA)을 사용하였다. 마이크로캡슐은 액중건조법을 이용하여 제조하였다. 교반속도와 안정제의 농도, 그리고 PCL의 분자량을 변화시키면서 마이크로캡슐을 제조하였으며 형성된 마이크로캡슐의 형태와 입자의 크기를 주사전자현미경을 이용하여 관찰하였다. 마이크로캡슐을 형성시킬 때, 교반속도가 빠를수록 작은 입자가 형성되었으며, 형성된 마이크로캡슐 안에 있는 향 오일의 방출속도는 사용된 PCL의 분자량이 클수록 지연되는 것을 확인할 수 있었다. 제조한 마이크로캡슐을 이용하여 실제 교실에서 학생들에게 aromatherapy를 시도해본 결과 마이크로캡슐화된 향 오일이 캡슐화하지 않은 향 오일보다 향이 지속되는 시간이 훨씬 길었으며 향 오일이 스트레스 완화, 소화작용 촉진, 피로도 감소, 집중력 향상에 효과가 있어 수험생에게 도움이 된다는 설문조사 결과를 얻었다.

• Journal of Microbiology and Biotechnology
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• 제23권10호
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• pp.1445-1453
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• 2013

The scale-up criterion of constant oxygen mass transfer coefficient ($k_La$) was applied for the production of itaconic acid (IA) in a 50 L pilot-scale fermentor by the fungal cells of Aspergillus terreus. Various operating conditions were examined to collect as many $k_La$ data as possible by adjusting the stirring speed and aeration rate in both 5 L and 50 L fermentor systems. In the fermentations performed with the 5 L fermentor, the highest IA production was obtained under the operating conditions of 200 rpm and 1.5 vvm. Accordingly, we intended to find out parallel agitation and aeration rates in the 50 L fermentor system, under which the $k_La$ value measured was almost identical to that ($0.02sec^{-1}$) of the 5 L system. The conditions of 180 rpm and 0.5 vvm in the 50 L system turned out to be optimal for providing almost the same volumetric amount of dissolved oxygen (DO) into the fermentor, without causing shear damage to the producing cells due to excessive agitation. Practically identical fermentation physiologies were observed in both fermentations performed under those respective operating conditions, as demonstrated by nearly the same values of volumetric ($Q_p$) and specific ($q_p$) IA production rates, IA production yield ($Y_{p/s}$), and specific growth rate (${\mu}$). Specifically, the negligible difference of the specific growth rate (${\mu}$) between the two cultures (i.e., $0.029h^{-1}$ vs. $0.031h^{-1}$) was notable, considering the fact that ${\mu}$ normally has a significant influence on $q_p$ in the biosynthesis of secondary metabolites such as itaconic acid.

• Bulletin of the Korean Chemical Society
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• 제32권2호
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• pp.625-629
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• 2011

A quantitative analysis of the decreasing rate of the monomer and increasing rate of the polymerization was made by monitoring radiation level increments using Raman spectroscopy within the therapeutic radiation range for a normoxic polymethacrylic acid gel dosimeter. The gel dosimeter was synthesized by stirring materials such as gelatin, distilled water, methacrylic acid, hydroquinone and tetrakis phosphonium chloride at $50^{\circ}C$, and the synthesized gel was contained in a 10- mm diameter and 32-mm high vial to conduct measurement. 24 hours after gel synthesis, it was irradiated from 0 Gy to 20 Gy by 2 Gy using a Co-60 radiotherapy unit. With use of the Cryo FE-SEM, structural changes in the 0 Gy and 10 Gy gel dosimeters were investigated. The Raman spectra were acquired using 532-nm laser as the excitation source. In accordance with fitting the changes in C-COOH stretching (801 $cm^{-1}$), C=C stretching (1639 $cm^{-1}$) and vinyl $CH_2$ stretching (3114 $cm^{-1}$) vibrational modes for monomer and $CH_2$ bending vibrational mode (1451 $cm^{-1}$) for polymer, sensitive parameter S for each mode was calculated. The values of S for monomer bands and polymer band were ranged in $6.0{\pm}2.6$ Gy and $7.2{\pm}2.3$ Gy, respectively, which shows a relatively good conformity of the decreasing rate of monomer and the increasing rate of polymerization within the range of error.

• Journal of Pharmaceutical Investigation
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• 제38권1호
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• pp.63-72
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• 2008

Meloxicam-loaded microspheres were prepared with poly(D,L-lactic acid)(PLA) by a solvent-emulsion evaporation method. The morphology, particle size, drug loading capacity, drug entrapment efficiency (EE) and release patterns of drug were investigated in vitro. Various batches of micro spheres with different size and drug content were obtained by changing the ratio of meloxicam to $PLA^{\circ}{\AE}s$ with different molecular weight, PLA concentration in the dispersed phase and stirring rate. Meloxicam crystals on microsphere surface, which were released rapidly and could act as a loading dose, were observed with increasing drug content. The release rate was increased with increase in drug contents and decrease in the molecular weight of PLA. Microspheres prepared with smaller molecular weight produced faster drug release rate. The release rate of meloxicam for long-acting injectable delivery system in vitro, which would aid in predicting in vivo release profile, could be controlled by properly optimizing various factors affecting characteristics of microspheres. Blood concentration-time profile of meloxicam after intramuscular injection of meloxicam-loaded microspheres in rabbits showed possibility of long term application of this system in clinical settings.

• Bulletin of the Korean Chemical Society
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• 제28권8호
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• pp.1375-1382
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• 2007

A column preconcentration method with pulverized Amberlite XAD-4 loaded with bismuthiol I (BI) has been developed for the determination of trace Cd(II) and Cu(II) in various real samples by flame atomic absorption spectrophotometry. Various experimental conditions, such as the size of XAD-4, adsorption flow rate, amount of bismuthiol I, stirring time for adsorbing bismuthiol I on XAD-4, pH of sample solution, amount of XAD-4- BI, desorption solvent, and desorption flow rate, were optimized. Also, the adsorption capacity and the adsorption rate of Cd(II) and Cu(II) on XAD-4-BI were investigated. The interfering effects of various concomitant ions were investigated, Bi(III), Sn(II) and Fe(III) were found to affect the determination. But the interference by these ions was completely eliminated by adjusting the amount of XAD-4-BI resin to 0.70 g, although the adsorption flow rate was slower. For Cd(II) our proposed technique obtained a dynamic range of 0.5-40 ng mL-1, a correlation coefficient (R2) of 0.9913, and a detection limit of 0.3 ng mL-1. For Cu(II), the corresponding values were 2.0-120 ng mL-1, 0.9921 and 1.02 ng mL-1. To validate this proposed technique, the aqueous samples (stream water, reservoir water, tap water and wastewater), the diluted brass sample and the plastic sample, as real samples, were used. Recovery yields of 91-103% were obtained. These measured data were not different from ICP-MS data at 95% confidence level. Our proposed method was also validated using rice flour CRM (normal, fortified) samples. From the results of our experiment, we found that the technique we present here can be applied to the determination of Cd(II) and Cu(II) in various real samples.

• 한국응용과학기술학회지
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• 제32권1호
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• pp.157-164
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• 2015

올레아놀릭산은 항암, 신행혈관 생성방지, 항염증, 항산화 및 주름 개선효과가 알려져 있다. 본 연구자들은 천연에서 분리한 올레아놀릭산의 항산화효과에 주목하여 연구하였고 미백효과가 있음을 확인하였다. 본 연구에서는 천연유래의 폴리글리세릴계 계면활성제를 사용하여 간단한 교반만으로 올레아놀릭산을 안정화하였고 고가의 장비인 마이크로풀루다이저를이용하여 제조한 레시틴리포좀과 경피흡수투과율을 비교하였다. 0.4% 올레아놀릭산을 안정화한 폴리글리세릴 나노에멀젼의 12시간 후 경피흡수투과율은 95%였다. 레시틴 리포좀은 92%로 유사하였으나 폴리글리세릴 나노에멀젼은 3시간 경피 흡수투과율이 65%로 레시틴리포좀의 45%에 비해 속방성의 특징을 보였다. 인체대상 임상시험결과 올레아놀릭산을 무배합한 대조군에 비해 올레아놀릭산을 배합한 폴리글리세릴 나노에멀젼은 MEXAMETER의한 멜라닌 색소감소효과가 2주차 25%, 4주차 58%, 8주차 58%이상 높았다.