• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.8
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• pp.1062-1068
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• 2009

Diacylglycerol (DAG) were synthesized by enzymatic esterification of glyceryl monooleate (GMO) and conjugated linoleic acid (CLA) in a shaking water bath. The reaction was catalyzed by Lipozyme TLIM (immobilized lipase from Thermomyces lanuginosa). Effects of reaction time, molar ratio, enzyme road and molecular sieves were studied. Results of normal-phase high performance liquid chromatography (NP-HPLC) analysis were performed. At 1:1, 2:1 and 3:1 (GMO : CLA) molar ratio and Lipozyme TLIM of 20% amount, DAG were produced in 42.6, 54.4 and 54.6 area% in 1 hr, respectively. When different Lipozyme TLIM amounts (2, 5, 10, 20%) were used with 2:1 (GMO : CLA) molar ratio, DAG were produced 21.4 (24 hr), 51.7 (12 hr), 56.2 (6 hr) and 54.4 (1 hr) area%, respectively. The reaction in the absence of molecular sieves increased DAG contents. The maximum DAG concentration conditions were obtained with molar ratio of 2:1 (GMO : CLA), lipase concentration of 10% (of substrate), 10% molecular sieves and reaction time of 6 hours at 55$^{\circ}C$. Under this reaction condition, produced DAG-rich oil was composed of 69 area% DAG, 7.9 area% TAG, 2 area% FFA, and 21.1 area% MAG.

• Progress in Medical Physics
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• v.22 no.3
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• pp.140-147
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• 2011

The purpose of this study was to estimate internal motion using molecular sieve for quantitative improvement of lung tumor and to localize lung tumor in the small animal PET image by evaluated data. Internal motion has been demonstrated in small animal lung region by molecular sieve contained radioactive substance. Molecular sieve for internal lung motion target was contained approximately 37 kBq Cu-64. The small animal PET images were obtained from Siemens Inveon scanner using external trigger system (BioVet). SD-Rat PET images were obtained at 60 min post injection of FDG 37 MBq/0.2 mL via tail vein for 20 min. Each line of response in the list-mode data was converted to sinogram gated frames (2~16 bin) by trigger signal obtained from BioVet. The sinogram data was reconstructed using OSEM 2D with 4 iterations. PET images were evaluated with count, SNR, FWHM from ROI drawn in the target region for quantitative tumor analysis. The size of molecular sieve motion target was $1.59{\times}2.50mm$. The reference motion target FWHM of vertical and horizontal was 2.91 mm and 1.43 mm, respectively. The vertical FWHM of static, 4 bin and 8 bin was 3.90 mm, 3.74 mm, and 3.16 mm, respectively. The horizontal FWHM of static, 4 bin and 8 bin was 2.21 mm, 2.06 mm, and 1.60 mm, respectively. Count of static, 4 bin, 8 bin, 12 bin and 16 bin was 4.10, 4.83, 5.59, 5.38, and 5.31, respectively. The SNR of static, 4 bin, 8 bin, 12 bin and 16 bin was 4.18, 4.05, 4.22, 3.89, and 3.58, respectively. The FWHM were improved in accordance with gate number increase. The count and SNR were not proportionately improve with gate number, but shown the highest value in specific bin number. We measured the optimal gate number what minimize the SNR loss and gain improved count when imaging lung tumor in small animal. The internal motion estimation provide localized tumor image and will be a useful method for organ motion prediction modeling without external motion monitoring system.

• Applied Chemistry for Engineering
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• v.3 no.1
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• pp.18-23
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• 1992

Three solid acid catalysts developed recently are reviewed. Cloverite is a gallophosphate molecular sieve with very large pore, titanium silicate has a specific structure compared with conventional molecular sieves, and Envirocat is prepared for the replacement of aluminium chloride catalyst.

• Proceedings of the Membrane Society of Korea Conference
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• 2004.11a
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• pp.169-171
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• 2004

• Proceedings of the Membrane Society of Korea Conference
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• 2002.11a
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• pp.88-92
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• 2002

No Abstract, See Full Text

• Proceedings of the Korean Ceranic Society Conference
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• 2002.10a
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• pp.199.1-199
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• 2002

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.2
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• pp.150-155
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• 2001

It has been observed that water, which is absolutely essential for enzyme activity, can induce the agglomeration of enzyme particles in organic media. Although enzyme agglomeration is significant in that it usually reduces enzyme activity and stability, little attention has been paid to the quantitative analysis of enzyme agglomeration behavior in nonaqueous biocatalytic systems. In this study, the effect of water and silica gel on enzyme agglomeration were investigated using Candida rugosa lipase and cyclohexane as a model enzyme and an organic medium. The extent of enzyme agglomeration was quantified by sieve analysis of freeze-dried agglomerates. Increasing the water content of the medium increased the size of the enzyme agglomerates, and it was found that water produced during the esterification reaction could also promote the agglomeration of enzyme particles suspended in organic media. On the other hand, the size of the enzyme agglomerates was remarkably reduced in the presence of silica gel at the same water content. We also show that this increase in the size of enzyme agglomerates results in lower reaction rates in organic solvents.

• Transactions of the Korean hydrogen and new energy society
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• v.35 no.1
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• pp.105-113
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• 2024

The natural gas dehydration process plays a central role in liquefying LNG. This study proposes two natural gas dehydration process systems applicable to liquefied natural gas (LNG) liquefaction plants, and compares and analyzes energy optimization measures through simulation. The fuel gas from feed stream (FFF) case, which requires additional equipment for gas circulation, disadvantages are design capacity and increased energy. On the other hand, the end flash gas (EFG) case has advantages such as low initial investment costs and no need for compressors, but has downsides such as increased power energy and the use of gas with different components. According to the process simulation results, the required energy is 33.22 MW for the FFF case and 32.86 MW for the EFG case, confirming 1.1% energy savings per unit time in the EFG case. Therefore, in terms of design pressure, capacity, device configuration, and required energy, the EFG case is relatively advantageous. However, further research is needed on the impact of changes in the composition of regenerated gas on the liquefaction process and the fuel gas system.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.6
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• pp.614-619
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• 2005

The activated carbon fibers of different surface area and pore structures were modified by carbon deposition from the pyrolysis of benzene, in an attempt to obtain carbon molecular sieves of high adsorption capacity and selectivity for the separation of $CO_2/CH_4$ gas mixtures. The ACFs molecular sieves prepared from different temperature and time were tested by the static adsorption of $CO_2$ and $CH_4$ gas, and their pore structures were characterized by the $N_2$ adsorption isotherms. We are able to prepare ACF molecular sieve with good selectivity for $CO_2/CH_4$ separation and showing acceptable adsorption capacities from the change of porosity by carbon deposition of pyrolyzed benzene.

• Applied Chemistry for Engineering
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• v.33 no.5
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• pp.488-495
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• 2022

Activated carbon (AC) and carbon molecular sieve (CMS) have attracted attention as porous materials for recovery and separation of greenhouse gases. The carbon molecular sieve having uniform pores is used for collecting and separating gases because it may selectively adsorb a specific gas. The size and uniformity of pores determine the performance of the CMS, and chemical vapor deposition (CVD) is widely used to coat the surface with a predetermined thickness in order to control the CMS's micropores. This CVD method can be used to control the size of pores in CMS manufacturing, but it must be optimized because of its various experimental variables. Therefore, in order to produce AC and CMS for gas adsorption and separation, this review focuses on various activation processes and pore control technologies by CVD and surface treatment.