• Journal of Sensor Science and Technology
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• v.1 no.1
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• pp.59-66
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• 1992

To develop the highly sensitive TLD radiation sensors, $BaSO_{4}$ : Eu-PTFE TLDs are fabricated by polymerizing the PTFE(polytetrafluoroethylene) with $BaSO_{4}$ : Eu TL phosphors. The $BaSO_{4}$ : Eu TL phosphors having the highest sensitivity of $X/{\gamma}$-rays are obtained by sintering at $1000^{\circ}C$ in $N_{2}$ atmosphere a mixture of $BaSO_{4}$ powder with 1mol% Eu($Eu_{2}O_{3}$), 6mol% $NH_{4}Cl$ and 5mol% $(NH_{4})_{2}SO_{4}$ which were co-precipitated in dilute sulfuric acid and then dried. The activation energy, frequency factor and kinetic order of $BaSO_{4}$ : Eu TL phosphor are 1.17eV, $3.6{\times}10^{11}/sec$ and 1.25, respectively. And the spectral peak of $BaSO_{4}$ : Eu is about 425nm. The optimum TL Phosphor content and thickness of the $BaSO_{4}$ : Eu-PTFE TLD are 40wt% and $105.7mg/cm^{2}$. The optimum polymerization temperature and time for fabrication of $BaSO_{4}$ : Eu-PTFE TLDs are $380^{\circ}C$ and 2 hours in air, respectively. The linear dose range to ${\gamma}$ rays is 0.01-20Gy and fading rate is about 10%/60hours.

• Polymer(Korea)
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• v.38 no.1
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• pp.103-107
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• 2014

Poly(acrylonitrile-butadiene-styrene) (ABS) composite sheets containing titanium dioxide ($TiO_2$), barium sulfate ($BaSO_4$), calcium carbonate ($CaCO_3$) were prepared by using a co-rotating twin screw extruder, and the reflectance and flexural modulus of the composite sheets were measured. The fillers were well dispersed in ABS matrix. The reflectance of composite sheet was increased with increasing $TiO_2$ and $BaSO_4$ content. Sheet having $TiO_2$ 20 wt% composition, with 5~20 wt% $BaSO_4$ resulted in more than 95% of reflectance. The flexural modulus of composite sheet was increased from 1864 MPa for $ABS/TiO_2/BaSO_4$ 85/10/5 (w/w/w) to 3134 MPa for $ABS/TiO_2/BaSO_4$ 55/20/25 (w/w/w).

• Journal of radiological science and technology
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• v.20 no.2
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• pp.68-72
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• 1997

Small bowel series using methylcellulose are considered a better technique than using other contrast media considering a significant decrease of transit time of $BaSO_4$ and that of the necessary time for the examination. We investigated the mean transit time of $BaSO_4$, maximum luminal diamenter of small bowel, optical density and flocculation frequency after adminstratting 100 ml of 120% $BaSO_4$ to 20 pts), 150 ml of 70% $BaSO_4$ to 20 pts and 200 ml of $BaSO_4$ with 600 ml of mechylcellulose. It was shown that the technique using 150 ml of 70% $BaSO_4$ had the best result. When we apply a adequate amount of density(w/v%), dosage to pts for small bowel series using MC, we can decrease an examination time and have the better image due to double contrast. It is considered that a more study to lower the density of 70% $BaSO_4$ is necessary.

• Bulletin of the Korean Chemical Society
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• v.29 no.5
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• pp.1007-1012
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• 2008

Spray pyrolysis has been found as an excellent method for the preparation of mesoporous barium sulfate at higher temperature. Ethylene glycol, a reducing agent, and solvents had good inhibition effect for the preparation of $BaSO_4$ nano particles. The $BaSO_4$ solution was sprayed at 500 & 800 ${^{\circ}C}$ using different solvents such as methanol, ethanol, propanol and n-butyl alcohol. $N_2$ adsorption-desorption isotherm revealed that $BaSO_4$ is micropore free, possessing narrow mesopores size distribution and high BET surface areas of 72.52 $m^2\;g^{-1}$ at 800 ${^{\circ}C}$ using propanol as an additive. Scanning electron microscopy (SEM) indicates that the morphology of $BaSO_4$ nano material shows uniform shell like particles. Transmission electron microscopy (TEM) proved that the resulting BaSO4 nano particles were uniform in size and the average particle size was 4-8 nm. The surface functionality and ethylene glycol peaks were assessed by Fourier transform infrared resonance (FTIR) spectroscopy. Low intensity ethylene glycol specific absorption peak was observed in propanol which proved that propanol had good inhibition effect on the structural morphology of nano particles.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.2
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• pp.101-112
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• 2016

This study investigated the removal of Sr, which was one of the high radioactive nuclides, by adsorption with Barium (Ba) impregnated 4A zeolite (BaA) from high-radioactive seawater waste (HSW). Adsorption of Sr by BaA (BaA-Sr), in the impregnated Ba concentration of above 20.2wt%, was decreased by increasing the impregnated Ba concentration, and the impregnated Ba concentration was suitable at 20.2wt%. The BaA-Sr adsorption was added to the co-precipitation of Sr with $BaSO_4$ precipitation in the adsorption of Sr by 4A (4A-Sr) within BaA. Thus, it was possible to remove Sr more than 99% at m/V (adsorbent weight/solution volume)=5 g/L for BaA and m/V >20 g/L for 4A, respectively, in the Sr concentration of less than 0.2 mg/L (actual concentration level of Sr in HSW). It shows that BaA-Sr adsorption is better than 4A-Sr adsorption in for the removal capacity of Sr per unit gram of adsorbent, and the reduction of the secondary solid waste generation (spent adsorbent etc.). Also, BaA-Sr adsorption was more excellent removal capacity of Sr in the seawater waste than distilled water. Therefore, it seems to be effective for the direct removal of Sr from HSW. On the other hand, the adsorption of Cs by BaA (BaA-Cs) was mainly performed by 4A within BaA. Accordingly, it seems to be little effect of impregnated Ba into BaA. Meanwhile, BaA-Sr adsorption kinetics could be expressed the pseudo-second order rate equation. By increasing the initial Sr concentrations and the ratios of V/m, the adsorption rate constants ($k_2$) were decreased, but the equilibrium adsorption capacities ($q_e$) were increasing. However, with increasing the temperature of solution, $k_2$ was conversely increased, and $q_e$ was decreased. The activation energy of BaA-Sr adsorption was 38 kJ/mol. Thus, the chemical adsorption seems to be dominant rather than physical adsorption, although it is not a chemisorption with strong bonding form.

• YAKHAK HOEJI
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• v.36 no.6
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• pp.538-547
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• 1992

Optimal synthetic condition of barium sulfate were investigated from the viewpoint of yield and bulkiness according to a randomized complete block design proposed by G.E.P. Box and K.B. Wilson. Barium chloride and magnesium sulfate were utilized as reactants in order to prepare barium sulfate in this study. It was found that optimum temperature range of reactant solutions was $60{\sim}100^{\circ}C$ and the optimum concentration range of the reactant solutions was $10{\sim}17.3%$ and $10{\sim}20%$ respectively, on the viewpoint of yield and bulkiness. The optimum mole ratio of $BaCI_2$ to $BaSO_4$ was in the range of $1.50{\sim}2.0$ and the optimum mole ratio of $BaCI_2$ to $BaSO_4$ was in the range of $1.50{\sim}2.0$ and the optimum reacting time range was $15{\sim}20$ minutes. The optimum drying temperature range was $110{\sim}130^{\circ}C$ from the viewpoint of yield, but it was $90{\sim}110^{\circ}C$ on the basis of bulkiness. Apparent viscosity of barium sulfate suspensions dispersed in various concentrations of Na. CMC was measured by using Brookfield synchrolectric viscometer model LVT, the relative equation, log ${\eta}_{sp}=A+B.{\phi}$ was examined and the equation was found to agree fairly well. 1 w/v% Na. CMC aqueous solution and 0.1 volume fraction of $BaSO_4$ powder were optimum in the preparation of $BaSO_4$ suspension showing highest viscosity at infinite shearing.

• Journal of radiological science and technology
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• v.26 no.1
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• pp.39-44
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• 2003

The aim of this study is to evaluate a efficient w/v% barium suspension and w/v% sodium carboxy methyl cellulose (SCMC) for small bowel examination. Between november 2001 and june 2002, 370 patients were examined small bowel examination with oral administration of barium suspension mixed with SCMC. we classified into six groups including A(fine type 40% $BaSO_4$ mixed 0.5% SCMC and 600 ml 0.5% SCMC administration), B(fine type 30% $BaSO_4$ mixed 0.5% SCMC), C(fine type 20% $BaSO_4$ mixed 0.5% SCMC), D(fine type 25% $BaSO_4$ mixed 0.5% SCMC), E(D mixed coarse type 25% $BaSO_4$ mixed 0.5% SCMC), F(D mixed coarse type 25% $BaSO_4$ mixed 0.75% SCMC). We measured transparency rate of contrast media transit time, administration dose, viscosity and particle size. The transparency rate was higher then 80 kV and 90 kV in 100 kV in the same 20 mAs condition. Transit time was the fastest in A group(mean trans time 56 minutes) and the slowest in E group(mean 100 minutes), Administration dose was the smallest in A group(mean dose 541 ml and the most in E group(mean 1,100 ml), viscosity was the lowest in E(125.1 mpa/s) and the highest in A(375.5 mpa/s), and particle size was $1.0\;{\mu}m$ in A, B, C, and D group, $0.6\;{\mu}m,\;1.0\;{\mu}m,\;10.0\;{\mu}m$ in E, F group. In conclusion, we propose that the efficient condition for small examination is high voltage technique, high density $BaSO_4$, and 0.625% w/v SCMC.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.381-384
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• 2008

The artificial lightweight aggregate was manufactured using stone-dust(SD) and bottom ash(BA) from crushed aggregate manufacture process and thermoelectric power plant respectively. The properties of artificial lightweight aggregate according to mixing ratio of SD and BA was that the density was decreased and the absorption was increased with increasing BA content, because bottom ash was contained many unburned carbon and $Fe_2O_3$ which generates gas by oxidation during a sintering process. The appropriate mixing ratio of SD and BA was estimated at about 5:5. The properties of artificial lightweight aggregate according to addition flux admixture was that it had lower density with increasing of $Na_2SO_4$ content. In this study, we could developed the artificial lightweight aggregate as the bulk density was $1.52g/cm^3$ and water absorption 7.3% under the condition that mixing ratio of SD:BA was 5:5, $Na_2SO_4$, $Fe_2O_3$ 1%, sintering temperature $1,150^{\circ}C$ and sintering time 15mins.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2004.11a
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• pp.47-52
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• 2004

The purpose of this study is to investigate the friction characteristics of brake pads according to different ratios of $BaSO_4/CaCO_3$. Four brake pads with different ratios of $BaSO_4/CaCO_3$ were manufactured. The friction characteristics of brake pads were tested using 1/5 reduced scale tester. With increasing of the amount of $BaSO_4$ density and shear strength of brake pads were increased and hardness of brake pads were decreased. In effectiveness, the friction coefficient of brake pad was higher and the stability of friction coefficient was better as the ratio of $BaSO_4$ increased. In fade test, friction coefficient of B3 sample used only $CaCO_3$ was decreased rapidly. B1 sample showed a good noise performance without noise generation. The wear resistance of samples were decreased with increasing of the ratio of $CaCO_3$.

• Korean Journal of Materials Research
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• v.19 no.7
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• pp.403-406
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• 2009

The friction characteristics of automotive brake friction materials that contained different ceramic content were investigated. Several kinds of raw materials, such as resin-based binder, reinforcing fiber, friction restraint, abrasive, and filling materials were mixed, pressed, and heated in order to make the brake friction materials. The contents of SiC and $BaSO_4$ changed from 5 vol% to 20 vol%, respectively. In addition to this, the content of $Al_2O_3$ adjusted from 1 vol% to 16 vol%. The surface morphology of the SiC containing sample appeared rough while more debris was observed when the contents of SiC increased. This implies that the SiC containing brake composite was not adequate for the automobile. However, the relatively smooth surface was observed in samples that contained the $Al_2O_3$. But the roughness was low with a content of 11 vol% $Al_2O_3$ compared to the other samples. This is consistent with the abrasive properties of the samples. In the case of $BaSO_4$ containing samples, the smoothes surface was observed in the contents of 15 vol% $BaSO_4$. Thus, it was concluded that the 11 vol% $Al_2O_3$ and 15 vol% $BaSO_4$ containing composite would be the optimum content for the brake composite. Similar to the results of the surface morphology, the abrasion resistance consistently decreased when the content of SiC increased. On the contrary, the sample that contained 11 vol% $Al_2O_3$ and 15 vol% $BaSO_4$ showed the highest abrasion resistance compared to the other samples.