• Nuclear Engineering and Technology
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• 제53권4호
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• pp.1318-1322
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• 2021

To unveil and delineate the elements applicable to the radiation protection of a femoral entry shield, calculate its mass attenuation coefficient, and demonstrate its dose reduction efficacy for interventional radiologist performing transarterial embolization (TAE) of ruptured hepatocellular carcinoma (rHCC). The lead equivalency of the shield was firstly validated. Electron microscopy was used to confirm the femoral entry shield being lead-free and to analyze the elemental content, with which the mass attenuation coefficient of the shield was calculated. An adult phantom, irradiated at the upper abdomen to simulate the TAE of rHCC, was used together with a dosimeter attached to the palm of a hand phantom. The dose rates at the hand phantom were measured, with the rHCC clinical protocol, without and with the femoral entry shield placed over the right femoral access site of the adult phantom. Without using the shield, the average hand dose rate was measured to be 0.325 µSv/sec. While using the shield, it was determined to be 0.110 µSv/sec. There was significant 66% dose reduction to the hand dose of IRs performing angiographic intervention with the femoral entry shield.

• Advances in nano research
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• 제7권3호
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• pp.169-180
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• 2019

Plasmonic effects of gold and platinum alloy nanoparticles (Au-Pt NPs) and their comparison to size was studied. Various factors including ratios of gold and platinum salt, temperature, pH and time of addition of reducing agent were studied for their effect on particle size. The size of gold and platinum alloy nanoparticles increases with increasing concentration of Pt NPs. Temperature dependent synthesis of gold and platinum alloy nanoparticles shows decrease in size at higher temperature while at lower temperature agglomeration occurs. For pH dependent synthesis of Au-Pt nanoparticles, size was found to be increased by increase in pH from 4 to 10. Increasing the time of addition of reducing agent for synthesis of pure and gold-platinum alloy nanoparticles shows gradual increase in size as well as increase in heterogeneity of nanoparticles. The size and elemental analysis of Au-Pt nanoparticles were characterized by UV-Vis spectroscopy, XRD, SEM and EDX techniques.

• Journal of the Korean Wood Science and Technology
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• 제47권3호
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• pp.277-289
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• 2019

Herein, a case study discussing the effect of carbonaceous aerosol pollution, which is emitted during the charcoal kiln manufacturing processes or carbonization processes, on the atmospheric environment is presented . In South Korea, in situ analysis of different charcoal production plants specialized in the production of charcoal sauna indicate that the emitted organic carbon (OC) and elemental carbon (EC) aerosols are significantly influenced by the nature of the biomass and technological processes, i.e., treatment or emissions abatement systems for the exhaust effluent gases. In detail, total carbon (TC), which is calculated as the sum of OC and EC emission factors, varied widely from a charcoal production site to another ranging from 21.8 to 35.8 gTC/kg-oak, where the mean value for the considered production sites was approximately 28 gTC/kg-oak (N = 7 and sum = 196.4). Results indicate that the emission factors from a modern charcoal production process in South Korea are quantitatively lower in comparison with the traditional kiln. This study aims to propose advanced wood processes for the production of charcoal from the viewpoint of environmental protection policy and green engineering.

• 대한화학회지
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• 제63권3호
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• pp.160-165
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• 2019

A series of reactions between an amino alcoholic ligand, cis-2-((2-((2-hydroxyethyl)amino)ethyl)amino)cyclohexan-1-ol (HEAC), with the mixtures of group 12 metals including, $HgCl_2/CdCl_2$, $HgCl_2/CdI_2$, $ZnCl_2/CdCl_2$ and $ZnCl_2/CdCl_2/HgCl_2$ was experimentally and theoretically studied to determine the most stable product of these reactions. Furthermore, the Cambridge Structural Database (CSD) studies were done to evaluate the theoretical results. The products were characterized by elemental analysis, FT-IR, Raman, $^1H$ NMR spectroscopy and single-crystal X-ray diffraction. Based on these investigations a binuclear structure of cadmium, [$Cd_2(HEAC)_2({\mu}-Cl)_2Cl_2$] (1), is the most stable product that was formed in all studied reactions between HEAC and metals mixtures. In this structure, the cadmium atom has a $CdN_2O({\mu}-Cl)_2Cl$ environment and distorted octahedral geometry.

• 대한화학회지
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• 제65권2호
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• pp.113-120
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• 2021

New phenylthiophenechalcones,1-(biphenyl-4-yl)-3-(5-phenylthiophen-2-yl)prop-2-en-1-one (3a) and 3-(5-phenylthiophen-2-yl)-1-(4-(piperidin-1-yl) phenyl) prop-2-en-1-one (3b) were synthesized, next, their treatment with thiosemicarbazide in ethanol afforded their pyrazoline derivatives (4a) and (4b), respectively. The molecular structures of the synthesized compounds were confirmed via elemental analysis, FT-IR, 1H, 13C NMR and mass spectroscopy. The geometrical elucidation of four suggested conformers has been studied for these compounds. DFT calculations have been performed to study the stability and the structural parameters of the predicted conformers and revealed that orientation of the biphenyl and the phenylthiophene moieties affect the stability of the estimated conformers of the synthesized chalcones and pyrazoline. Moreover, two reaction mechanisms have been proposed to illustrate the reaction products and the DFT calculations have been used to confirm the reaction mechanism of the pyrazoline compounds.

• 한국재료학회지
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• 제31권8호
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• pp.450-457
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• 2021

From measured thermal conductivity and modeling by simulation, this study suggests that U-factors are highly related to materials used between steel and polymer. The objective and prospective point of this study are to relate the relationship between the U-factor and the thermal conductivity of the materials used. For the characterization, EDX, SEM, a thermal conductive meter, and computer simulation utility are used to analyze the elemental, surface structural properties, and U-factor with a simulation of the used material between steel and polymer. This study set out to divide the curtain wall system that makes up the envelope into an aluminum frame section and entrance frame section and interpret their thermal performance with U-factors. Based on the U-factor thermal analysis results, the target curtain wall system is divided into fix and vent types. The glass is 24 mm double glazing (6 mm common glass +12 mm Argon +6 mm Low E). The same U-factor of 1.45 W/m²·K is applied. The interpretation results show that the U-factor and total U-value of the aluminum frame section are 1.449 and 2.343 W/m²·K, respectively. Meanwhile, those of the entrance frame section are 1.449 and 2.

• Membrane and Water Treatment
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• 제13권6호
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• pp.321-335
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• 2022

Copper-based Metal-organic framework (MOF) namely ([Cu (INA)₂]-MOF) is synthesized by ball milling and characterized using scanning electron microscopy (SEM) for the topography, microstructure, and elemental evidence determination, powdered X-ray diffraction (XRD) for the crystallinity measurement, thermogravimetric (TG) analysis was performed to determine the thermal stability of the material, and Fourier transformed infrared (FTIR) spectroscopy for functional groups identification. The use of [Cu (INA)₂]-MOF as hazardous removal material of β-agonists as persistent hazardous micro-pollutants in our environmental water is first reported in this study. The removal efficiency of the Cu-MOF is successfully determined to be 97.7% within 40 minutes, and the MOF has established an exceptional removal capacity of 835 mg L^-1 with 95 % percent removal on Clenbuterol (CLB) even after the 5th consecutive cycle. The Langmuir model of the adsorption isotherms was shown to be more favourable, while the pseudo-second-order model was found to be favoured in the kinetics. The reaction was exothermic and spontaneous from a thermodynamic standpoint, and the higher temperatures were unfavourable for the adsorption study of the CLB. As a result, the studied MOF have shown promising properties as possible adsorbents for the removal of CLB in wastewater.

• Nuclear Engineering and Technology
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• 제55권3호
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• pp.902-907
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• 2023

To understand the eutectic reaction mechanism and the relocation behavior of the core debris is indispensable for the safety assessment of core disruptive accidents (CDAs) in sodium-cooled fast reactors (SFRs). This paper addresses reaction products and their distribution of the eutectic melting/solidifying reaction of boron carbide (B₄C) and stainless-steel (SS). The influence of the existence of carbon on the B₄C-SS eutectic reaction was investigated by comparing the iron boride (FeB)-SS reaction by Raman spectroscopy with Multivariate Curve Resolution (MCR) analysis. The scanning electron microscopy with dispersive X-ray spectrometer was also used to investigate the elemental information of the pure metals such as Cr, Ni, and Fe. In the B₄C-SS samples, a new layer was formed between B₄C/SS interface, and the layer was confirmed that the formed layer corresponded to amorphous carbon (graphite) or FeB or Fe₂B. In contrast, a new layer was not clearly formed between FeB and SS interface in the FeB-SS samples. All samples observed the Cr-rich domain and Fe and Ni-rich domain after the reaction. These domains might be formed during the solidifying process.

• Geomechanics and Engineering
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• 제34권5호
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• pp.473-480
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• 2023

Acid rain of soils has a significant impact on mechanical properties. An X-ray diffraction test, scanning electron microscope (SEM) test, laser particle size analysis test, and triaxial unconsolidated undrained (UU) test were carried out in red clay soils with different compaction degrees under the effect of different concentrations of acid. The experiments demonstrated that: the dissolution effect of acid rain on colluvium weakened with the increase in the compacting degree under the condition of certain pH values, i.e., the damage to the structure of red clay soil was relatively light, where the number of newly increased pores in the soil decreased and the agglomeration of soil particles increased; for the same compacting degree, the structural gap decreased, and the agglomeration increased with the increase in the pH value (acidity decreases) of the acid rain; the dissolution rate of Si, Al, Fe, and other elemental minerals and cement in red clay soil was found to be higher under the effect of acid rain, in turn destroying the original structure of the soil body and producing a large number of pores. This is macroscopically expressed as the decrease of the soil cohesion and internal friction angle, thereby reducing the shear strength of the soil body.

• 한국재료학회지
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• 제34권5호
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• pp.247-253
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• 2024

The separation of zirconium and hafnium using tributyl phosphate (TBP)-Dodecane extractants in nitric acid medium was performed. Zirconium oxychloride, used as extraction feed, was obtained from the synthesis of Kalimantan zircon sand concentrate smelted using NaOH. The extraction process was carried out by dissolving chloride-based metals in nitric acid media in the presence of sodium nitrate using TBP-Dodecane as an extractant. Some of the extraction parameters carried out in this study include variations in organic phase and aqueous phase (O/A), variations in contact time, and variations in nitric acid concentration. Extraction was carried out using a mechanical shaker according to the parameter conditions. X-ray fluorescence (XRF) was used for elemental (Zr and Hf) composition analysis of the aqueous solution. The results showed that zirconium was separated from hafnium at optimum conditions with an organic/aqueous ratio of 1:5, contact time of 75 min, and an HNO₃ concentration of 7 M. The resulting separation factor of zirconium and hafnium using TBP-Dodecane was 14.4887.