• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.12
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• pp.593-598
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• 2001

Transient liquid phase processing was investigated to decrease processing temperatures while maintaining useful piezoelectric properties in the lead zirconate titanate (PZT) system. Niobium oxide$(Nb_2O_5)$ modified crystalline PZT (PZTN) powder was combined with lead silicate $(PS; PbO-SiO_2)$ glass powder and crystalline titania, zirconia, and niobia. Firing above the melting temperature of the lead silicate $(PS; Tm \risingdotseq\; 714^{\circk}C)$ resulted in liquid phase densification of the PZTN followed by dissolution of the titania, zirconia, and niobia into the liquid phase, and crystallization of additional PZTN. The addition of crystalline titania, zirconia, and niobia to react with the lead oxide from the lead silicate phase resulted in an increase in the dielectric and Piezoelectric properties.

• Journal of radiological science and technology
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• v.46 no.3
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• pp.187-195
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• 2023

A shield was made by mixing materials such as bismuth(Bi) and barium(Ba) with silicon to evaluate its shielding ability. Bismuth was made into a shield by mixing a bismuth oxide(Bi₂O₃) colloidal solution and a silicon base and applied to a fibrous fabric, and barium was made by mixing lead oxide(PbO) and barium sulfate(BaSO₄) with a silicon curing agent and solidifying it to make a shield. The test was conducted according to the lead equivalent test method for X-ray protective products of the Korean Industrial Standard. The experiment was conducted by increasing the shielding body one by one from the test condition of 60 kVp, 200 mA, 0.1sec and 100 kVp, 200 mA, 0.1 sec. At 60 kVp, 2 lead oxide-barium sulfate shields, 2 bismuth oxide 1.5 mm shields, and 5 bismuth oxide 0.3 mm shields showed shielding ability equal to or higher than that of lead 0.5 mm. At 100 kVp, 2 lead oxide-barium sulfate shields and 2 bismuth oxide 1.5 mm shields showed shielding ability equal to or higher than that of lead 0.5 mm. It was confirmed that when using 2 pieces of lead oxide-barium sulfate and 1.5 mm of bismuth oxide, respectively, it has shielding ability equivalent to that of lead. Bismuth oxide and lead oxide-barium sulfate are lightweight and have excellent shielding ability, thus they have excellent properties to be used as an apron for radiation protection or other shielding materials.

• Journal of the Korean Society of Radiology
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• v.15 no.5
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• pp.715-721
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• 2021

In radiation brachytherapy, the wrong source location may cause excessive dose to normal tissue. Therefore, research on digital dosimeters is being made to replace the analog detection method. Therefore, in this study, a lead (II) oxide (PbO) dosimeter applied with a passive layer (PL) was fabricated as a basic study to improve the dosimeter performance. Afterwards, reproducibility, linearity, and distance dependence were evaluated to analyze the performance of the Ir-192 source under irradiation conditions. The reproducibility of the PL-PbO dosimeter was 0.40%, which satisfies the evaluation criteria of 1.5%, and showed improved results compared to the PbO dosimeter. Linear function R2 showed excellent results as 0.9995, and slope analysis through regression analysis of the linear function was excellent in PL-PbO. The distance dependence of the PL-PbO dosimeter was +0.599 higher than that of PbO when the slope obtained through regression analysis of the power function was compared with the inverse square value. This study presents the effects and measurement variables according to the measurement configuration of the solid-state dosimeter, and can be used in various radiation detection fields.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.347.2-347.2
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• 2016

Recently, in order to improve the performance of the colloidal quantum dot solar cells (CQDSCs), various efforts such as the modification of the cell architecture and surface treatment for quantum dot (QD) passivation have been made. Especially, the incorporation of halides into the QD matrix was reported to improve the performances significantly via passivating QD trap states that lower the life-time of the minority-carrier. In this work, we fabricated a lead sulfide (PbS) QD bilayer treated with different ligands and utilized it as a photoactive layer of the CQDSCs. The bottom and top PbS layer was treated using metal iodide ($MI_x$ and butanedithiol (BuDT), respectively. All the depositions and ligand treatments were carried out in air using layer-by-layer spin-coating process. The fabrication of the active layers as well as the n-type zinc oxide (ZnO) layer was successfully carried out on the bendable indium-tin-oxide (ITO)-coated polyethylene terephthalate (PET) substrate, which implies that this technique can be applied to the fabrication of flexible and/or wearable solar cells. The power conversion efficiency (PCE) of the CQDSCs with the architecture of $PET/ITO/ZnO/PbS-MI_x/PbS-BuDT/MoO_x/Ag$ reached 4.2 %, which is significantly larger than that of the cells with single QD (PbS-BuDT) layer.

• Journal of the Korean Society for Heat Treatment
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• v.35 no.3
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• pp.130-138
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• 2022

In this study, the characteristic of an amorphous fishing weight material according to controlling the alloy type and alloy composition of the glass forming agent added in PbO₂ oxide was investigated. According to the experimental, when the glass forming agent of 15wt%SiO₂-1wt%MgO content was added in β-PbO₂, an amorphous fishing weight substitute having the lowest friction coefficient, excellent corrosion resistance and durability was obtained. The cell number of PbO₂-15wt%SiO₂-1wt%MgO sample incubated in cell culture fluid tended to hardly decrease even after a lapse of 24 hours, It means that the fabricated PbO₂-15wt%SiO₂-1wt%MgO sample is significantly less-toxic and harmless to the human body, unlikely to metallic lead. It is considered that an fabricated amorphous fishing weight substitute proved to have a potential as an eco-friendly material with little marine pollution.

• Journal of the Korean Society of Radiology
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• v.15 no.6
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• pp.781-788
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• 2021

Due to the high sensitivity to radiation, excessive exposure needs to be prevented by accurately measuring the dose irradiated to the skin during radiation therapy. Although clinical trials use dosimeters such as film, OSLD, TLD, glass dosimeter, etc. to measure skin dose, these dosimeters have difficulty in accurate dosimetry on skin curves. In this study, to solve these problems, we developed a skin dosimeter that can be attached according to human flexion and evaluated its response characteristics. For the manufacture of the dosimeter, lead oxide (PbO) with high atomic number (Z_Pb: 82, Z_O: 8) and density (9.53 g/cm³) and silicon binders that can bend according to human flexion were used. In the case of a dosimeter made of PbO material, the performance degradation has been prevented by using parylene and others due to the presence of degradation due to oxidation, but the previously used parylene is affected by bending, so a new form of passive layer was produced and applied to the skin dosimeter. The characteristic evaluation of the skin dosimeter was evaluated by analyzing SEM, reproducibility, and linearity. Through SEM analysis, bending was evaluated, reproducibility and linearity at 6 MeV energy were evaluated, and applicability was assessed with a skin dosimeter. As a result of observing the dosimeter surface through SEM analysis, the parylene passive layer PbO dosimeter with the positive layer raised to the parylene produced cracks on the surface when bent. On the other hand, no crack was observed in the silicon passive layer PbO dosimeter, which was raised to silicon passive layer. In the reproducibility measurement results, the RSD of the silicon passive layer PbO dosimeter was 1.47% which satisfied the evaluation criteria RSD 1.5% and the linearity evaluation results showed the R² value of 0.9990, which satisfied the evaluation criteria R² 9990. The silicon passive layer PbO dosimeter was evaluated to be applicable to skin dosimeters by demonstrating high signal stability, precision, and accuracy in reproducibility and linearity, without cracking due to bending.

• Journal of the Korean Society of Radiology
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• v.15 no.1
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• pp.79-83
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• 2021

In radiation therapy, electron beam is often used in the treatment of superficial lesion. Accurate measurements are required because electron beam interacts with them in the beam path and affects dose measurements. However, no research has been conducted on electron beam quality assurance. in this study, PbO-based dosimeter was fabricated as a basic study for electron beam quality assurance. Thus, the reproducibility and linearity of the energy of 6, 9, and 12 MeV were analyzed to evaluate measurement accuracy and precision. Reproducibility measurements show RSD value of 1.024%, 1.019% and 0.890%, respectively, at 6, 9, and 12 MeV. linearity measurements show 0.9999 R2 at 6, 9, and 12 MeV altogether. Both evaluations show that the PbO dosimeter has very good measurement accuracy and precision with excellent results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.6
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• pp.457-460
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• 2005

Nano-sized titanium oxide and zirconium oxide powders were synthesized by hydrolysis of titanium isopropoxide $[Ti(OC_3H7)_4]$ and zirconium tetrachloride ($ZrC1_4$) via a sol-gel technique. Lead titanate powders were prepared by mixing $TiO_2$ precursors with PbO slurry made with dilute $NH_4OH$. Lead zirconate titanate powders were, then, synthesized by mixing $PbTiO_3$ with $ZrO_2$ powders. The goal of this research was to obtain the $PbZrTiO_3(PZT)$ powders and sintering these powders at low temperature. The $PbTiO_3$ and PZT powders after firing were analyzed by X-ray diffraction(XRD) and transmission electron microscopy(TEM) was utilized to observe the shape and size of the synthesized nano-particles. In the XRD pattern, the well-crystallized PZT phase could be obtained in consequence of firing at $900^{\circ}C$. SEM micrographs also showed that grains of PZT were relatively well grown with the size of the range of $2{\~}4{\mu}m$. The densified perovskite structure of $PbZrTiO_3$ could be obtained by sintering at temperature as low as $900^{\circ}C$. Characterization of the samples showed improved piezoelectric properties.

• Corrosion Science and Technology
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• v.11 no.3
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• pp.96-102
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• 2012

Outer diameter stress corrosion cracking (ODSCC) has occurred for Alloy 600 (Ni 75 wt%, Cr 15 wt%, Fe 10 wt%) as a heat exchanger tube of the steam generator (SG) in nuclear power plants (NPP) during long term operation. Among many causes for SCC, lead (Pb) is known to be one of the most deleterious species in the secondary system. In the present work, the oxide formed on Alloy 600 was characterized as a function of the PbO content in 0.1 M NaOH at $315^{\circ}C$ by using an electrochemical impedance spectroscopy (EIS), a transmission electron microscopy (TEM), equipped with an energy dispersive x-ray spectroscopy (EDS). The oxide property was analyzed in view of SCC susceptibility.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.593-596
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• 2003

A proposed way to prepare $YBa_2Cu_3O_y$ wires or tapes is that Ag is used as substrate and melting point of $YBa_2Cu_3O_y$ is decreased to lower than the melting point of silver ($961\;^{\circ}C$). Therefore after the deposition of $YBa_2Cu_3O_y$ film on Ag substrate, the heat treatment can be carried out below the Ag melting point. Silver (Ag) and Lead oxide(PbO) were selected to be additives for $YBa_2Cu_3O_y$. Different Ag and PbO contents were added in $YBa_2Cu_3O_y$, the melting points of which were measured by DTA. In order to guarantee that the superconductivity of $YBa_2Cu_3O_y$ was not reduced after Ag and PbO added into $YBa_2Cu_3O_y$, their superconductivities were measured. It is proved that as additives, both Ag and PbO can reduce the melting point of $YBa_2Cu_3O_y$. For Ag doped $YBa_2Cu_3O_y$, $T_c$ is about 93K and ${\Delta}Tc$ is $2{\sim}3K$. For PbO doped $YBa_2Cu_3O_y$, $T_c$ is $88K{\sim}92K$ and ${\Delta}T_c$ is $11{\sim}12K$. When 10 wt% of Ag and 10 wt% PbO were added in $YBa_2Cu_3O_y$, the melting point of the mixture of $YBa_2Cu_3O_y$ (80 wt%), Ag (10 wt%) and PbO (l0 wt%) is $943^{\circ}C$. The transition temperatures ($T_c$) of the sample is 91.8 K.