• Journal of Korean Society of Industrial and Systems Engineering
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• v.46 no.3
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• pp.59-68
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• 2023

Currently, yellow phosphor of Y3Al5O12:Ce3+ (YAG:Ce) fluorescent material is applied to a 450~480nm blue LED light source to implement a white LED device and it has a simple structure, can obtain sufficient luminance, and is economical. However, in this method, in terms of spectrum analysis, it is difficult to mass-produce white LEDs having the same color coordinates due to color separation cause by the wide wavelength gap between blue and yellow band. There is a disadvantage that it is difficult to control optical properties such as color stability and color rendering. In addition, this method does not emit purple light in the range of 380 to 420nm, so it is white without purple color that can not implement the spectrum of the entire visible light spectrum as like sunlight. Because of this, it is difficult to implement a color rendering index(CRI) of 90 or higher, and natural light characteristics such as sunlight can not be expected. For this, need for a method of implementing sunlight with one LED by using a method of combining phosphors with one light source, rather than a method of combining red, blue, and yellow LEDs. Using this method, the characteristics of an artificial sunlight LED device with a spectrum similar to that of sunlight were demonstrated by implementing LED devices of various color temperatures with high color rendering by injecting phosphors into a 405nm deep blue LED light source. In order to find the spectrum closest to sunlight, different combinations of phosphors were repeatedly fabricated and tested. In addition, reliability and mass productivity were verified through temperature and humidity tests and ink penetration tests.

• Journal of Hydrogen and New Energy
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• v.34 no.6
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• pp.601-607
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• 2023

Pyrolysis oil (C5-C20) produced using plastic non-oxidative pyrolysis technology produces naphtha oil (C5-C10) through a separation process, and naphtha oil produces hydrogen through a reforming reaction to secure economic efficiency and social and environmental benefits. In this study, waste plastic pyrolysis oil was subjected to a steam reforming reaction on a commercialized catalyst of 46-3Q And it was found that the 46-3Q catalyst reformed the pyrolysis oil to produce hydrogen. Therefore, an experiment was performed to increase hydrogen yield and minimize the byproduct of ethylene. The reaction experiment was performed using actual waste plastic oil (C8-C11) with temperature, steam/carbon ratio (S/C) ratio, and space velocity as variables. We studied reaction conditions that can maximize hydrogen yield and minimize ethylene byproducts.

• Biomolecules & Therapeutics
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• v.32 no.3
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• pp.379-389
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• 2024

This study was aimed to evaluate endogenous metabolic changes before and after cisplatin and radiation therapy in patients with cervical cancer via untargeted metabolomic analysis using plasma samples. A total of 13 cervical cancer patients were enrolled in this study. Plasma samples were collected from each patient on two occasions: approximately one week before therapy (P1) and after completion of cisplatin and radiation therapy (P2). Of the 13 patients, 12 patients received both cisplatin and radiation therapy, whereas one patient received radiation therapy alone. The samples were analyzed using the Ultimate 3000 coupled with Q Exactive^TM Focus Hybrid Quadrupole-Orbitrap^TM mass spectrometry (Thermo Fisher Scientific, Waltham, MA, USA). Chromatographic separation utilized a Kinetex C18 column 2.1×100 mm (2.6 ㎛) (Phenomenex, Torrance, CA, USA), and the temperature was maintained at 40℃. Following P2, there were statistically significant increases in the concentrations of indoxyl sulfate, phenylacetylglutamine, Lysophosphatidyethanolamine (LysoPE) (18:1), and indole-3-acetic acid compared with the concentrations observed at P1. Specifically, in the human papillomavirus (HPV) noninfection group, indoxyl sulfate, LysoPE (18:1), and phenylacetylglutamine showed statistically significant increases at P2 compared with P1. No significant changes in metabolite concentrations were observed in the HPV infection group. Indoxyl sulfate, LysoPE (18:1), phenylacetylglutamine, and indole-3-acetic acid were significantly increased following cisplatin and radiation therapy.

• Analytical Science and Technology
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• v.37 no.1
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• pp.25-38
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• 2024

The study aimed to investigate a novel approach by utilizing liquid chromatography (LC) and liquid chromatography-mass spectrometry (LC-MS) to separate, identify and characterize very nominal quantities of degradation products (DPs) of balsalazide along with its process related impurities without isolation from their reaction mixtures. The impurities along with balsalazide were resolved on spherisorb ODS2 (250×4.6 mm, 5.0 ㎛) column at room temperature using 0.2 M sodium acetate solution at pH 4.5 and methanol in the ratio of 55:45 (v/v) as mobile phase pumped isocratically at 1.0 mL/min as mobile phase and UV detection at 255 nm. The method shows sensitive detection limit of 0.003 ㎍/mL, 0.015 ㎍/mL and 0.009 ㎍/mL respectively for impurity 1, 2 and 3 with calibration curve liner in the range of 50-300 ㎍/mL for balsalazide and 0.05-0.30 for its impurities. The balsalazide pure compound was subjected to stress studies and a total of four degradation products (DPs) were formed during the stress study and all the DPs were characterized with the help of their fragmentation pattern and the masses obtained upon LC-MS/MS. The DPs were identified as 3-({4-[(E)-(4-hydroxyphenyl) diazenyl]benzoyl}amino)propanoic acid (DP 1), 4-[(E)-(4-hydroxyphenyl)diazenyl] benzamide (DP 2), 5-[(E)-(4-carbamoylphenyl)diazenyl]-2-hydroxybenzoic acid (DP 3) and 3-({4-[(E)-phenyldiazenyl]benzoyl}amino)propanoic acid (DP 4). Based on findings, it was concluded that, the proposed method was successfully applicable for routine analysis of balsalazide and its process related impurities in pure drug and formulations and also applicable for identification of known and unknown impurities of balsalazide.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.57 no.3
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• pp.216-226
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• 2024

This study screened the antimicrobial and anti-inflammatory activities of three extracts [1% acetic acid (HAc), distilled water (D.W.), and ethanol] from the common stalked barnacle Pollicipes mitella. Among the extracts, the 1% HAc extract showed the strongest antibacterial activity against several bacteria, but exhibited no activity against Candida albicans. To improve the degree of separation of the 1% HAc extract, solid-phase extraction was performed using a C18 cartridge with three solvents (D.W., 60A, and 100A). The 1% HAc 60A eluate showed the strongest antibacterial activity and enzyme, salt, and temperature stability, with no hemolytic activity. In addition, strong DNA-binding ability but no bacterial membrane permeability was observed. These results indicate that the P. mitella 1% HAc 60A eluate may contain antibacterial organic compounds that target intracellular components but not bacterial membranes. In addition, the 1% HAc 60A eluate exhibited potent inhibitory activity to reduce the production of inflammatory mediators (nitric oxide and prostaglandin E₂) and pro-inflammatory cytokines (tumor necrosis factor-α, interleukin (IL)-6, and IL-1β) with no cytotoxicity. Therefore, the P. mitella 1% HAc 60A eluate has anti-inflammatory activity. Collectively, our results suggest that the P. mitella 1% HAc 60A eluate can be used as a bioactive source with antibacterial and anti-inflammatory activities.

• Korean Chemical Engineering Research
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• v.50 no.4
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• pp.684-689
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• 2012

Poly(acrylic acid) (PAA) microspheres is one of the widely-used polymeric materials for the bio-field application and the electric materials. For the synthesis of PAA microspheres, the polymerization technique using surfactants is applied. After the synthesis, the purification and separation processes are required for the removal of surfactant. When general organic solvents were used, many problems, such as huge amount of waste solvent, additional separation processes, and the possibility of residual media, were occurred. Thus, High-pressure Soxhlet extraction using liquid $CO_2$ was developed to solve these problems. In this study, High-pressure Soxhlet extraction of the synthesized PAA microspheres using liquid $CO_2$ was conducted for the removal of Monasil PCA which is used for the dispersion polymerization of acrylic acid in compressed liquid Dimethyl ether (DME). The morphology of the extracted PAA particles was checked by field emission scanning electron microscopy (FE-SEM) and the residual concentration of Monasil PCA was analyzed by inductively coupled plasma - Optical Emission Spectrometer (ICP-OES). For studying the effect of the solvent effect, Soxhlet extraction was conducted using n-hexane, liquid DME, and liquid $CO_2$. In case of n-hexane, some extracted PAA microspheres were produced. However, deformation was also occurred due to the high thermal energy of n-hexane vapor. Liquid DME could not remove Monasil PCA. When using liquid $CO_2$, the extracted PAA microspheres which were free for the residual solvent were produced without deformation. For finding the optimum operating condition, high-pressure Soxhlet extraction was conducted for 8 hours with changing the temperature of reboiler and condenser. When the extractor temperature is $19.6{\pm}0.2^{\circ}C$ and the pressure is $51.5{\pm}0.5$ bar, the best removal efficiency was obtained.

• Journal of the Korean Wood Science and Technology
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• v.38 no.3
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• pp.230-241
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• 2010

The purpose of this study was to seek the optimum condition for effective separation of the chemical constituents of wood biomass by means of hydrolysis of acetone solution in presence of acid salt as a catalyst. Out of diverse acid salts the catalytic effect of aluminum sulfate ($Al_2(SO_4)_3$) was the most excellent during the hydrolysis of wood biomass in the acetone solution and the optimum concentration was 0.01 M (6.3 wt%). In the condition of mixture ratio of acetone and water to 9 : 1 as well as optimum concentration of aluminum sulfate two wood biomass species, oak wood (Quercus mongolica Fischer) and Pine wood (Pinus densiflora Sieb. et Zucc.), was hydrolyzed for 45 minutes at $200^{\circ}C$ and the degree of hydrolysis was determined to 92.7% and 92.4%, respectively. Extending the reaction time to 60 minutes in the mixture ratio of acetone and water to 8 : 2 the degree of hydrolysis of oak wood was also ca. 92.7%. In the case of Pinus, however, the similar hydrolysis ratio was obtained at $210^{\circ}C$. As the temperature and hydrolysis time increased, the quantitative amount of lignin recovered from the hydrolysate clearly increased, whereas the total amount of carbohydrates in the hydrolysate decreased rapidly. Considering the recoverable amount of lignin and carbohydrate in the hydrolysate, the best condition for the hydrolysis of wood biomasses were confirmed to the mixture ratio of acetone and water to 8 : 2, the concentration of aluminum sulfate of 6.3 wt%, hydrolysis temperature of $190^{\circ}C$ for 60 minutes. In this condition the total amounts of carbohydrate in the hydrolysates of oak wood and pine wood were estimated to 47.6% and 51.4%, respectively. The amount of lignin recovered from the hydrolysates were ca. 18.2% for oak wood and 13.7% for pine wood.

• Membrane Journal
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• v.25 no.2
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• pp.191-201
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• 2015

We have studied on the preparation of $TiCo_xFe_{1-x}$(x=0.50~1.00) system alloy, the characteristics of $TiCo_xFe_{1-x}$(x=0.50~1.00) system alloy by X-ray diffractometer (XRD), pressure composition temperature (PCT) curve, scanning electron microscopy (SEM) and the $H_2-N_2$ gas mixture separation of $TiCo_xFe_{1-x}$(x=0.50~1.00)- stainless steel (SS) composite membranes. The formation of $TiCo_xFe_{1-x}$(x=0.50~1.00) system alloys with cubic crystal same as TiCo was confirmed by X-ray diffractometer. $TiCo_xFe_{1-x}$(x=0.50~1.00) system alloys showed the hysteresis at $120^{\circ}C$. As the Fe content of $TiCo_xFe_{1-x}$(x=0.50~1.00) system alloys increased, the hysteresis was increased both range x=0.90~1.00 and x=0.55~0.60, and the range x=0.55~0.90 gave decreased hysteresis. $TiCo_{0.55}Fe_{0.45}$ alloy was the one showed the lowest hysteresis among them. The lowest value of hydrogen permeation pressure of $TiCo_xFe_{1-x}$(x=0.50~1.00)-SS composite membrane was $TiCo_{0.55}Fe_{0.45}$-SS composite membrane with the value of 2.5 atm at $120^{\circ}C$; otherwise, $TiCo_{0.90}Fe_{0.10}$-SS composite had the highest pressure value among the membranes with the value of 10 atm. $TiCo_{0.55}Fe_{0.45}$-SS composite membrane was the best to separate the $H_2-N_2$ gas mixture excellently among the $TiCo_xFe_{1-x}$(x=0.50~1.00)-SS composite membranes since $TiCo_{0.55}Fe_{0.45}$ had the least hysteresis, and hydrogen permeation pressure was the lowest with value of 2.5 atm.

• Membrane Journal
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• v.22 no.2
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• pp.113-119
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• 2012

$YBaCo_2O_{5+{\delta}}$ oxide was synthesized by solid state reaction and a typical dense membrane has been prepared using as-prepared powder by unilateral pressing and sintering at $1,180^{\circ}C$. The $YBaCo_2O_{5+{\delta}}$ membraneswas analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). XRD analysis showed the double layered perovskite structure was observed over $1,150^{\circ}C$ without impurities. Oxygen permeation was measured in the temperature range from 750 to $950^{\circ}C$ according to oxygen partial pressure difference between feed and permeation side. The oxygen permeation flux increased with increasing temperature and oxygen partial pressure and the maximum oxygen flux of $YBaCo_2O_{5+{\delta}}$ membrane with 1.0 mm thickness was about 0.15 mL/$cm^2{\cdot}min$ at $950^{\circ}C$ and $PO_2$ = 0.42 atm. The activation energy for oxygen permeation decreased with decreasing oxygen partial pressure to be 76.0 kJ/mol at the condition of $PO_2$ = 0.21 atm.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.2
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• pp.49-55
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• 2016

The effects of post-annealing and temperature/humidity conditions on the interfacial adhesion energies of atomic layer deposited RuAlO diffusion barrier layer for Cu interconnects were systematically investigated. The initial interfacial adhesion energy measured by four-point bending test was $7.60J/m^2$. The interfacial adhesion energy decreased to $5.65J/m^2$ after 500 hrs at $85^{\circ}C$/85% T/H condition, while it increased to $24.05J/m^2$ after annealing at $200^{\circ}C$ for 500 hrs. The X-ray photoemission spectroscopy (XPS) analysis showed that delaminated interface was RuAlO/$SiO_2$ for as-bonded and T/H conditions, while it was Cu/RuAlO for post-annealing condition. XPS O1s peak separation results revealed that the effective generation of strong Al-O-Si bonds between $AlO_x$ and $SiO_2$ interface at optimum post-annealing conditions is responsible for enhanced interfacial adhesion energies between RuAlO/$SiO_2$ interface, which would lead to good electrical and mechanical reliabilities of atomic layer deposited RuAlO diffusion barrier for advanced Cu interconnects.