• Journal of Pharmaceutical Investigation
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• v.31 no.3
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• pp.167-172
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• 2001

All-trans retinoic acid (ATRA), vitamin A acid, has been shown to exert anticancer activity in a number of types of cancers, particularly in acute promyelocytic leukaemia (APL). Due to its highly variable bioavailability and induction of its own metabolism after oral treatment, development of parenteral dosage forms are required. However, its poor aqueous solubility and chemical unstability give major drawbacks in parenteral administration. This study was undertaken to investigate a possibility to develop a parenteral formulation of ATRA by employing solid lipid nanoparticle (SLN) as a carrier. By optimizing the production parameters and the composition of SLNs, SLNs with desired mean particle size (<100 nm) as a parenteral dosage form could be produced from trimyristin (as solid lipid), Egg phosphatidylcholine and Tween 80 (as SLN stabilizer). The mean particle size of SLN formulation of ATRA was not changed during storage, suggesting its physical stability. Thermal analysis confirmed that the inner lipid core of SLNs exist at solid state. The mean particle size of ATRA-loaded SLNs was not significantly changed by the lyophilization process. ATRA could be efficiently loaded in SLNs, while maintaining its anticancer activity against HL-60, a well-known APL cell line. Furthermore, by lyophilization, ATRA loaded in SLN could be retained chemically stable during storage. Taken together, our present study demonstrates that physically and chemically stable ATRA formulation adequate for parenteral administration could be obtained by employing SLN technology.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.835-837
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• 1998

Current lead plays the part of connector between ambient temperature and liquid helium superconducting magnet. Having zero resistance characteristic, it is expected that HTS has very low thermal conductivity and generate no joule heat when fabricated to current lead. In particular, among the HTS meterials, HTS tape has high Jc and Ag-sheath of tape plays the part of stabilizer, but it has too poor mechanical strength to be applied and when fabricated as long length tape, it has tendency to decline Jc seriously. In this study, we fabricated Bi-2223 multifilamentary tapes and then made current lead with stacking type using them. Through this work, we conclude that the defect of HTS long length tape is decreased by addition the number of stacking tape and that current lead is able to operate more stably by minimizing the gap of tapes.

• YAKHAK HOEJI
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• v.43 no.6
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• pp.793-797
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• 1999

Salmonella typhi Ty21a is an attenuated strain of S. typhimurium and used for oral typhoid vaccine. In an attempt to increase the stability of Ty21a manufacturing typhoid vaccine, we studied about the stability of freeze-dried Th21a including additives at various temperature conditions. In order to investigate the freeze-drying rate of Ty21a according to various absorbance, we lyophilized Ty21a by using 8% sucrose as a stabilizer. The optimal freeze-drying rate of Ty21a was appeared when OD (optical density) value of the growth was between 2.5 and 3.0. To investigate the stability of Ty21a at various temperature, the viability was measured after storaging the freeze-dried Ty21a at the room temperature, cold and freezing condition for 1 week. The viability of Ty21a in cold and freezing storage condition was 5 times more stable than in room temperature. To search the most stable additives for the freeze-dried Ty21a, the viability of Ty21a including additives at the various storage condition was estimated. Mannitol and loctose were the most stable additives. Theses results suggest that the OD value of Ty21a growth, low temperature, mannitol and lactose are important factors for the optimal freeze-drying rate, the stable storage and the most stable additives, respectively.

• Journal of Radiation Industry
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• v.7 no.1
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• pp.23-28
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• 2013

In this study, we fabricated high density polyethylene (HDPE) composites filled with antioxidants and UV stabilizers. The electron beam irradiation on the fabricated composites was carried out over a range of absorbed doses from 50 to 200 kGy to confirm the changes of discoloration. The changes of discoloration were characterized using a color difference meter and FT-IR for confirming the changes of the color difference and structural change. It was observed that the color difference of IRGANOX 1010-, IRGAFOS 168-, and TINUVIN 328- added HDPE was higher than that of the control HDPE by electron beam irradiation. The melting temperature of UV stabilizer-added HDPE was not significantly changed by electron beam irradiation. However, the melting temperature of phenol-containing antioxidant-added HDPE was increased with increasing the absorbed dose. And the melting temperature of phosphorus-containing antioxidant-added composite was decreased with increasing the absorbed dose.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.365-366
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• 2009

This study researched into the manufacture of current-limit module of using YBCO coated conductor. Regarding over-current of exceeding the critical current, the quench characteristics were researched according to the stabilizing layer through tendency in resistance, which is generated in conductor, by applying over-current to YBCO coated conductors, which have stabilizing layer. YBCO coated conductors, which were used in experiment, include one kind such as the conductor, which used stainless as the stabilizing layer. The critical current is 70 A. And, the critical temperature is with 90 K. First of all, the quench generation was researched under over-current of exceeding the critical current by using this YBCO coated conductors. The tendency of a rise in the detected voltage according to the applied current was measured. And, the tendency of a rise in resistance through voltage-current curve was measured. As a result, the point of time in thermal quench of conductor, which has stainless as the stabilizing layer, could be confirmed to be fast.

• Journal of the Korean Society of Propulsion Engineers
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• v.12 no.2
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• pp.74-80
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• 2008

The feasibility study into the development of turbine spinners, which start up the turbo-pump, has been carried out and the design requirements and parameters ranges have been presented. Turbine spinners use the solid propellant as such composite propellant based AN compound with high energy plasticizers, coolants, and phase stabilizer which relieves a sensible volume change due to the phase transformation of AN near room temperature. Propellants which have a homing rate of $0.2{\sim}0.3\;mm/s$ and pressure exponent ranged from 0.3 to 0.6, showed stable burn-out in the standard motor tests. Both the magnitude of ignition energy and its thermal transfer mechanism have been proved to have a tangible effect on the ignition of the pyre starter, and the results of this study showed that a flame temperature of 1400K would be quite adequate to get a stable ignition for the AN composite propellant.

• Journal of the Korean Electrochemical Society
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• v.25 no.4
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• pp.191-200
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• 2022

Na-β"-Al₂O₃ has been widely employed as a solid electrolyte for high-temperature sodium (Na) beta-alumina batteries (NBBs) thanks to its superb thermal stability and high ionic conductivity. Recently, a vapor phase conversion (VPC) method has been newly introduced to fabricate thin Na-β"-Al₂O₃ electrolytes by converting α-Al₂O₃ into β"-Al₂O₃ in α-Al₂O₃/yttria-stabilized zirconia (YSZ) composites under Na⁺ and O^2- dual percolation environments. One of the main challenges that need to be figured out is lowered conductivity due to the large volume fraction of the non-Na⁺-conducting YSZ. In this study, the effect of lithia addition in the β"-Al₂O₃ phase on the grain size and ionic conductivity of Na-β"-Al₂O₃/YSZ solid electrolytes have been investigated in order to enhance the conductivity of the electrolyte. The amount of pre-added lithia (Li₂O) precursor as a phase stabilizer was varied at 0, 1, 2, 3, and 4 mol% against that of Al₂O₃. It turns out that ionic conductivity increases even with 1 mol% lithia addition and reaches 67 mS cm^-1 at 350 ℃ of its maximum with 3 mol%, which is two times higher than that of the undoped composite.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.5 no.3
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• pp.171-177
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• 2007

This study suggested a new method to stabilize molten salt wastes generated from the pyre-process for the spent fuel treatment. Using conventional sol-gel process, $SiO_2-Al_2O_3-P_2O_5$ (SAP) inorganic material that is reactive to metal chlorides were prepared. In this paper, the reactivity of SAP with the metal chlorides at $650{\sim}850$, the thermal stability of reaction products and their leach-resistance under the PCT-A test method were investigated. Alkali metal chlorides were converted into metal aluminosilicate($LixAlxSi1-_xO_{2-x}$) and metal phosphate($Li_3PO_4\;and\;Cs_2AlP_3O_{10}$) While alkali earth and rare earth chlorides were changed into only metal phosphates ($Sr_5(PO_4)_3Cl\;and\;CePO_4$). The conversion rate was about $96{\sim}99%$ at a salt waste/SAP weight ratio of 0.5 and a weight loss up to $1100^{\circ}C$ measured by thermogravimetric analysis were below 1wt%. The leach rates of Cs and Sr under the PCT-A test condition were about $10^{-2}g/m^2\;day\;and\;10^{-4}g/m^2\;day$. From these results, it could be concluded that SAP can be considered as an effective stabilizer for metal chlorides and the method using SAP will give a chance to reduce the volume of salt wasteform for the final disposal through further researches.

• Elastomers and Composites
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• v.34 no.3
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• pp.199-211
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• 1999

In this work, the effects of the addition of epoxy on the properties of PVC-sol sealants were investigated. PVC-sol was plasticized with dioctyl phthalates(DOP). Two kinds of epoxy resins having different epoxy equivalent weight (E.E.W.) were used. It was found that the properties of the PVC-sol sealants were significantly affected by the contents and types of the added epoxy resins. The viscosity behaviors of the epoxy-modified sealants, in the case of epoxy A addition, the viscosity was decreased with increasing the epoxy contents, but In the case of $CaCO_3$ addition, the viscosity was increased with increasing the $CaCO_3$ contents. The viscosity of epoxy modified sealants aged at $45^{\circ}C$ waterbath was decreased with increasing epoxy contents, since the epoxy acted on the sealants as a stabilizer. The thermal stability of the PVC-sol sealants was slightly improved by adding epoxy. The tensile strength and elongation of sealants modified with epoxy A(two functionalities of epoxy) were increased with increasing the epoxy contents up to a certain epoxy contents but was decreased with further increasing the epoxy contents. In the case of $CaCO_3$ addition, the tensile strength of sealants were decreased with increasing the $CaCO_3$ contents. In view of the electrical properties, such as tan ${\delta}$($0.1{\pm}0.04$) and ${\epsilon}_r$($0.5{\pm}0.04$), it was found that the epoxy modified sealants were as good as insulators.

• Elastomers and Composites
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• v.37 no.1
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• pp.7-13
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• 2002

In this study, mechanical properties of PVC complexes containing the gypsum (Namhae Chemical Co.) which contains phosphte, CaO, etc., Pb-species stabilizer, and $CaCO_3$ were investigated as a function or the content. As a result, mechanical properties increased when the gypsum was mixed with PVC at the extent of 8.46wt%. From this result, it is suggested that the gypsum containing phosphate and CaO is compatible with PVC. Thermogravimetric analysis(TGA) showed that pyrolysis started about at $275^{\circ}C$, and residual weight(%) increased with the amount of the gypsum, and differential scanning calorimetry (DSC) showed that $T_m,\;T_g$ had the maximum and minimum value respectively when the gypsum was mixed with PVC at the extent of 8.46wt%. Comparing all the results, both mechanical and thermal properties of PVC complex were improved. The X-ray diffraction measurement also showed their blonds and structures.