• Journal of the Korean institute of surface engineering
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• v.49 no.6
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• pp.567-574
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• 2016

We have analyzed chemical properties of polysiloxane and polysilazane films, respectively, as sealing materials for electrostatic chuck (ESC) and have investigated the possibility of polysilazane as an alternative sealant to polysiloxane. It has been revealed that Si-O with organic bonding ($Si-CH_3$) existed in polysiloxane films compared to only pure Si-O bonding in polysilazane films. The sealing property of polysilazane has been found outstanding even in a short time of application. In the polysiloxane films containing $H_2O$, pin holes have been found possibly due to $CO_2$ gas evolution, and low adhesion with Si substrate has been observed after heat stress test in connection with the existence of organic bonding. After acid resistance test in 0.5 vol.% HF, 68 wt.% $HNO_3$, and 37 wt.% HCl solution, polyilazane films have shown a longer survival times. Compared to the conventional polysiloxane sealant, polysilazane is expected as a new sealing material because of good thermal and chemical stability.

• Journal of Adhesion and Interface
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• v.15 no.1
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• pp.14-21
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• 2014

In the present work, PLA/PBS blends with poly(lactic acid) (PLA) and poly(butylene succinate) (PBS) at different contents were processed by using a twin-screw extruder and an injection molding machine, and then their mechanical, thermal and morphological properties were investigated. The mechanical properties such as flexural strength, flexural modulus, tensile strength and tensile modulus and thermal properties such as melting behavior, dynamic mechanical thermal properties and thermal stability significantly depended on the contents of PLA and PBS. However, the heat deflection temperature of the blends was not significantly influenced by the contents of PLA and PBS. Also, the fracture surfaces of PLA/PBS blends were changed from a brittle pattern to a ductile pattern with increasing the PBS contents.

• The Korean Journal of Food And Nutrition
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• v.13 no.6
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• pp.534-538
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• 2000

Sample frying oil was manufactured from simple mixing treatment of capsicum. butter flavor and silicone resin. the amount were 0.20, 0.15% ($\omega$/$\omega$) and 10 rpm in soybean oil, respectively. This frying oil was confirmed to improving of heat stability as well as removal effect of meat flavor. Frying oil obtained from treatment of capsicum and silicone resin was appeared, acid value and smoke point were 0.301, 232$\^{C}$, than its value in the non-treated soybean oil were 0.385. 220$\^{C}$, respectively, in the case of continuous frying at 185$\pm$2$\^{C}$. These effects were likely to according both anti-oxidation effect of capsicum and inhibition of free fatty acids and smoke production from anti-expansion of surface area in frying oil. Meat flavor and burnt flavor of oil in the frying oil and fried foods were weakened by treating of butter flavor(0.15%, $\omega$/$\omega$), this effect will be produced to new type\`s frying oil product.

• Journal of Korean Society of Water and Wastewater
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• v.34 no.2
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• pp.127-137
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• 2020

In this study, a MWCNT(multi-wall carbon nanotube) was added to polysulfone(PSf) support layer to improve flux of TFC(thin film composite) RO(reverse osmosis) membrane. Two different kinds of MWCNT were used. Surfaces of some MWCNTs were modified hydrophilically through acid treatment, while those of other MWCNTs were modified through heat treatment to maintain their hydrophobicity. MWCNT/PSf support layer was prepared by adding PSf to the NMP mixed solvent containing 0.1 wt% MWCNTs using a phase inversion method. The surface porosity of the MWCNT/PSf support increased by 42~46% while its surface pore size being maintained. The TFC RO membrane made of MWCNT/PSf support layer showed a 20% flux increase while its salt rejection characteristics is sustained. In addition, the MWCNT/PSf support layer has better mechanical stability than the PSf support layer, there resulting in an increased resistance of flux reduction due to physical pressure.

• Archives of Pharmacal Research
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• v.3 no.1
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• pp.7-12
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• 1980

Ampliciline was synthesized from 6-amino-pencillanic acid (6-APA) and D-.alpha. phenylglycine methyl ester by using amplicilin synthesizing enzyme from Peudomonas melanogenum (IAM 1655). The whole cell enzyme was immobilized by entrapping it in the polyacrylamide gel lattices. The polymer used in the enzyme entrapment was made from 150 mg per ml of acrylamide monomer and 8 mg per ml of N, N'-methylenebisacrylamide. About 200 mg/whole cell enzyme was mixed in the polymer for entrapment. The maximal activity retention after immobilization was 56%. The optimal pH values for the whole cell enzyme and the immobilized whole cell enzyme were 6.0 and 5.9, respectively. The optimal temperature for the enzyme activity were the same for both type of preparations. The enzyme stabilities against pH and heat increased for immobilized whole cell enzyme. Immobilized cell was more stable especially in the acidic condition while both type were found to be very suceptible to thermal inactivation at a temperature above 4.deg.C. The kinetic constants obtained from Lineweaver-Burk plot based on two substate reaction mechanism showed somewhat higher value for immobilized whole cell enzyme as compared to the whole cell enzyme : the Km value for 6-APA were 7.0 mM and 12.5 mM while Km values for phenylglycine methyl ester were 4.5 mM and 8.2 mM, respectively. Using the immobilized whole cell enzyme packed in a column reactor, the productivity of ampiciline was studied by varying the flow rate of substrate solution. At the space velocity, SV, 0.14 hr$^{-1}$ the conversion was 45%. Operational stability found in terms of half life was 30 hr at SV = 0.2 hr.

• The Korean Journal of Food And Nutrition
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• v.11 no.2
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• pp.243-248
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• 1998

Ark shell was known as shellfish that had hemoglobin as blood pigment and the action of mecidine, was consumed the great part of it as raw material, though it was produced about 13,000 M/T per year. Ark shell was processed the infinitesimal quantity as conned product, bout canned ark shell had problem that occurrenced discoloration after heat treatment during processing and storage. This discoloration mechanism during processing and storage was not cleared. This study was carried out to understand characteristics of the hemoglobin as blood pigment and carotenoid as meat pigment in ark shell and management of proper processing conditions for prevention of oxidation and discoloration by thermal treatment. When treated by digestion of 0.1% BHA, 0.1% Tenox-II, 0.5% Na2EDTA, 0.05% NDGA and 3% salt soln., 0.1% BHA solution was most suitable for stability of carotenoid that the retention ratio of carotenoids were 63.1% after heating to 116$^{\circ}C$ for 120 minutes. In preparation of canned ark shell and storage at 37$\pm$1$^{\circ}C$ for 60 days, the chemical composition, pH and salinity ere stable. And contents of total carotenoid were decreased slightly from 0.83mg% to 0.727mg%. The viable cell count were 6.92$\times$103 cfu/ml at raw ark shell, after processed and storage were not detected. The predominant amino acids in the raw ark shell were glutamic acid(19.7%), arginine(16.0%), glycine(12.6%), alanine(12.2%) and aspartic acid(7.6%). When 60 days stored, the contents of amino acid were stable. And the predominant nuclotide and their related compounds in the raw ark shell were hypoxanthine(2.14$\mu$mol/g), IMP(1.94$\mu$mol/g) and ATP(0.87$\mu$mol/g), and storage at 37$\pm$1$^{\circ}C$ for 60 days, the quantity order were same as raw material.

• Journal of Life Science
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• v.32 no.3
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• pp.232-240
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• 2022

Various methods are known for preparing liposomes, the simplest being the Bangham method which has been widely used. Although it is possible to produce liposomes effectively on a small experimental level with this approach, large-scale production cannot be easily performed due to difficulties in removing the organic solvent and the size of the reactor required to form the lipid film. On the other hand, emulsion can mass produce tons of liposomes with uniform particles but has the disadvantage of a significantly low capture rate. This study therefore developed an optimal liposome processing method using heat with improved capture rate and stability, and bio-absorption experiments were performed by oral administration to SD rat alongside capture rate, particle size, and zeta potential. Through the heating method, a small and uniform liposome of about 214 nm was formed and the capture rate was 38.67%, confirming that the liposome prepared by heating has a higher capture rate than the 26.46% achieved through emulsion. Comparing blood concentrations, it showed a 1.5 to 2 fold increase in all groups, gradually decreasing until 4-12 hr. The highest blood concentration of ascorbic acid powder was about 12.017 ㎍/ml, the emulsion liposome 13.871 ㎍/ml, and the heating liposome 16.322 ㎍/ml, thereby showing an improved absorption rate.

• Applied Chemistry for Engineering
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• v.19 no.5
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• pp.526-532
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• 2008

The proposed $CO_2$ storage technology in the present study is a one-step sequestration process that stabilizes $CO_2$ in a reactor with Serpentine. The advantage of this technology is associated with its high stability of final product so that the entire system is recognized as permanent environment-friendly $CO_2$ removal method. Since the sequestration reaction mechanisms are generally understood that carbonation reaction proceeds with very slow rate, so that pretreatment method to increases reaction rate of $CO_2$ carbonation reaction should be developed. To increase the reactivity of Serpentine with $CO_2$, two different methods of pretreatment are carried out in the present investigation. One is heat-treatment, the other is chemical pretreatment. In this study, only chemical pretreatment is considered leaching method of magnesium from Serpentine using sulfuric acid at the various reaction temperatures, times, and acid concentrations. Experimental results illustrated that pretreatment by sulfuric acid increases surface area of serpentine from $11.1209m^2/g$ to $98.7903m^2/g$ and extracts magnesium compounds. Single variable experiment demonstrated the enhancements of magnesium extraction with increased reaction temperature and time. Amount of magnesium extraction is obtained by using the data of ICP-AES as maximum extraction condition of magnesium is 2 M acid solution, $75^{\circ}C$ and 1hr. After performing chemical pretreatment, carbonation yield increased from 23.24% to 46.30% of weight.

• Clean Technology
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• v.25 no.1
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• pp.33-39
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• 2019

A.C (activated carbon) is mainly used to remove VOCs (volatile organic compounds), however, it has many problems such as fire risk due to increasing of adsorbent surface temperature during VOCs ad/desorption, increased cost by frequent replacement cycles requirement and performance degradation when containing moisture. In order to solve these problems, many researches, hydrophobic zeolite adsorbents, have been reported. In this study, $NH_4{^+}Y$-zeolite was synthesized with Y-zeolite through steam treatment and acid treatment, which is one of the hydrophobic modification methods, to secure high surface area, thermal stability and humidity resistance. The Y, Y-550-HN, Y-600-HN and Y-650-HN had adsorption capacities of $23mg\;g^{-1}$, $38mg\;g^{-1}$, $77mg\;g^{-1}$, $61mg\;g^{-1}$. The change of Si/Al ratio, which is an index to confirm the degree of modification, was confirmed by XRF (X-ray fluorescence spectrometer) analysis. As a result, the adsorbtion performance was improved when Y-zeolite modified, and the Si/Al ratio of Y, Y-550-HN, Y-600-HN, Y-650-HN were increased to 3.1765, 6.6706, 7.3079, and 7.4635, respectively. Whereas it was confirmed that structural crystallization due to high heat treatment temperature affected performance degradation. Therefore, there is an optimal heat treatment temperature of Y-zeolite, optimum modification condition study could be a substitute for activated carbon as a condition for producing an adsorbent having high durability and stability.

• Korean Journal of Food Science and Technology
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• v.36 no.4
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• pp.677-682
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• 2004

Debates on safety of genetically modified (GM) crops have led to mandatory-labeling legislation of GM foods in many countries including Korea. Effects of heat, pressure, and acid treatments on degradation of DNAs or proteins in GM soybean at levels below detection limits of qualitative PCR and lateral flow strip test (LFST) methods were examined. Results showed that genomic DNAs and proteins were degraded into fragment sizes no longer possible for detection of inserted gene depending on thermal, or thermal and pressure treatment period. Detectaability of LFST for toasted meal increased in weakly treated soybean. DNA and protein detection methods were barely effective for detection of GM ingredient after $121^{\circ}C$ and 1.5 atmospheric treatment for 20 min. These results will be useful in determining GM labeling requirements of processed foods.