• Korean Journal of Clinical Laboratory Science
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• v.53 no.1
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• pp.1-10
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• 2021

Radiopharmaceuticals are drugs that contain radioisotopes and are used in the diagnosis, treatment, or investigation of diseases. Radiopharmaceuticals must be manufactured in compliance with good manufacturing practice regulations and subjected to quality control before they are administered to patients to ensure the safety of the drug. Radiopharmaceuticals for administration to humans need to be sterile and pyrogen-free. Hence, sterility tests and membrane filter integrity tests are carried out to confirm the asepticity of the finished drug product, and a bacterial endotoxin test conducted to assess contamination, if any, by pyrogens. The physical appearance and the absence of foreign insoluble substances should be confirmed by a visual inspection. The chemical purity, residual solvents, and pH should be evaluated because residual by-products and impurities in the finished product can be harmful to patients. The half-life, radiochemical purity, radionuclidic purity, and strength need to be assessed by analyzing the radiation emitted from radiopharmaceuticals to verify that the radioisotope contents are properly labeled on pharmaceuticals. Radiopharmaceuticals always carry the risk of radiation exposure. Therefore, the time taken for quality control tests should be minimized and care should be taken to prevent radiation exposure during handling. This review discusses the quality control procedures and acceptance criteria for a diagnostic radiopharmaceutical.

• Membrane Journal
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• v.32 no.2
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• pp.140-149
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• 2022

In this study, the conditions of low temperature and high pressure of biogas upgrading process using polysulfone membrane have been designed and tested to achieve the high recovery and efficiency corresponding to those of the highly selective polymeric materials. Polysulfone hollow fiber membrane with 4-component dope solution was spun via non-solvent induced phase separation. The hollow fiber membrane was mounted into a 1.5 inch housing. The effective area was 1.6 m², and its performance was examined in various operation temperatures and pressures. CO₂ and CH₄ permeances were 412 and 12.7 GPU at 20℃, and 280 and 3.6 GPU at -20℃, respectively, while the CO₂/CH₄ selectivity increased from 32.4 to 77.8. Single gas test was followed by the mixed gas experiments using single-stage and double stage where the membrane area ratio varied from 1:1 to 1:3. At the single-stage, CH₄ purity increased and the recovery decreased as the stage-cut increased. At the double stage, the area ratio of 1:3 showed the higher CH₄ recovery as decreasing the operation temperature at the same purity of CH₄ 97%. Finally, polysulfone hollow fiber membranes have yielded of both CH₄ purity and recovery of 97% at -20℃ and 16 barg.

• Membrane Journal
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• v.24 no.3
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• pp.213-222
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• 2014

In this study, 2-stage recirculation membrane process was developed for purification of high purity bio-methane for the vehicle fuel application. Pure gas permeation and mixture gas permeation test were done as a function of methane content and pressure in the feed using polysulfone membrane modules. 2-stage membrane plant was designed, constructed in a food waste treatment cite. Dehumidification, dry desulfurization, and desiloxane plants are installed for the removal of $H_2O$, $H_2S$ and siloxane in the biogas. Permeation test were done with the pre-treated methane mixture in terms of methane purity and recovery by adjusting the ratio of membrane area (1:1, 1:3, 2:2) in the first and second membrane modules in the plant. When membrane area of 2 stage increased to $3m^2$ from $1m^2$ at 1-stage membrane area of $1m^2$, the feed rate and $CH_4$ recovery at 95% methane purity were increased from 47.1% to 92.5% respectively. When the membrane area increased two-fold (1:1 to 2:2), $CH_4$ recovery increased from 47.1% to 88.3%. When the feed flow rate was increased, in 1:3 ratio, final purity of the methane is reduced, the methane recovery is increased. When operating pressure was increased, the feed rate was increased and recovery was slightly decreased. From this result, membrane area, feed pressure and feed rate could be the important factor to the performance of the membrane process.

• Analytical Science and Technology
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• v.25 no.6
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• pp.483-491
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• 2012

This study is to investigate the issues on how to secure stability during the purification process for the production of recombinant protein A. The final recombinant protein A is produced by passing through the cation exchange column (SP) and the anion-exchange column (Q) during the production process, for which the samples produced by the step-by-step processes can be exposed to trouble in securing stable storage in case the next process cannot be taken within the proper time period. Accordingly, this study aims to evaluate the proper storage conditions and length of time when storing samples produced in the production process. That is, in this study, how to store fair samples, how long the storage period should be set up, and how to evaluate the security of its quality depending on time are dealt with. The items to be experimented with were enodotoxin, SDS-PAGE, HPLC purity and concentration. Experimental results showed that after passing the cation exchange column, when stored at $4^{\circ}C$ or room temperature, SDS-PAGE showed a major band, endotoxin is 5.0 Eu/mg or less, and concentration is on average of 8.21 to 8.24 mg/mL and RSD% 0.10~0.62%. In addition, HLPC purity showed somewhat stable results; at the HPLC purity 214 nm, the average is 99.24% to 99.37% and RSD% is 0.22~0.29%, while the average is 89.72% to 89.80% and RSD% 0.62~1.26% at 280 nm. On the contrary, after passing the anion exchange column, when stored at $4^{\circ}C$ or room temperature, SDS-PAGE revealed the major band, endotoxin is 0.5 Eu/mg or less, and concentration is on average of 5.59 mg/mL and RSD% 0.03~0.10%. when it comes to HLPC purity, the result showed that at the HPLC purity 214 nm, the average is 99.74% and RSD% is 0.10~0.11%, while the average is 96.16% to 96.85% and RSD% 0.72~1.13%. In conclusion, the stability of fair samples of recombinant protein A during the manufacturing process could be obtained without substance decomposition for 7~8 days at $4^{\circ}C$ or 20~21 days at room temperature.

• Journal of the Korean Ceramic Society
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• v.33 no.11
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• pp.1217-1222
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• 1996

Undoped barium titanate ceramic samples with high density were produced by using both high purity hydro-thermally synthesized and oxalate-derived powders. Sintering temperature was varied in the temperature range 128$0^{\circ}C$-140$0^{\circ}C$ to control the average grain sizes of the samples. Electrical breakdown test was performed at two different temperature with 3$0^{\circ}C$(below Tc) and 15$0^{\circ}C$ (above Tc) for samples immersed in silicon oil bath using 60kV dc power supply. From the experimental results at below and above Curie temperature the grain size and thickness dependence of electrical breakdown strength for BaTiO3 ceramics was presented and breakdown behavior was also studied.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.7
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• pp.62-70
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• 1997

In this paper, the optical conditins of a reflective multi-color STN-LCD based on electrical control of birefringence is designed on the poincare sphere. First of all, the angles of polarizer and analyzer for the best color purity are decided in the configuration without a retardation film. A retardation film is introduced for a bright white in the range of the applied voltage. The sretardation and the angle of the retardation film are also decided on the poincare shpere. The test cell is farbricated and its measured spectral transmittance and the CIE chromaticity diagram agree well with simulations.

• Journal of Korea Foundry Society
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• v.7 no.1
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• pp.28-37
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• 1987

The progression of the solidification wave front in V-section and finned casting was studied by use of the pour-out test, employed with high. Purity aluminum. The results obtained were as follows; a) The shape of solidification wave front at the inside and outside corners did not change according to solidification time, but it changes according to the corner angles at a given molding and melting condition. b) The cooling fin effect could be repserented as functions of solidification time and fin sise, and this result could be applied to enhance the accuracy of the section modulus method in the design of T and V section.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.10 no.1
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• pp.42-48
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• 1984

The comparative detergency of Sodium dodecyl sulfate (SDS) solution near the first critical micelle concentration (CMC) was measured by means of a 131 I-labelled castor oil as a soil. More than 95% radiochemical purity of 131 I-labelled castor oil was obtained using potassium lidide as a carrier. Polyester test fabric was soiled with 131 I-labelled castor oil, and washed in a conventional washing apparatus mounted on appropriate devices. Fabric radioactivities were measured before and after washing by a scintilation counter. Near the first CMC, the detergency of SDS was increased with decreasing of surface tension of SDS. It was also shown that 131 I-labelled castor oil was useful for studying the detergency of SDS.

• Journal of Dairy Science and Biotechnology
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• v.17 no.1
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• pp.11-15
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• 1999

The objective of this study was to extract and purity the antibacterial agent from the fermented milk with Lactobacillus helveticus CH-1. The extraction and purification of antibacterial agent from the Lb. helveticus fermented milk were carried out by methanol extraction, acetone extraction, Sephadex G-200 gel filteration and thin layer chromatography and the results were as followings. The antibacterial activity of methanol-acetone extraction showed antibacterial activity against test organisms, B. subtilis, E. coli, Pseu. fluorescens, Sal. typhimurium, Shi. flexneri, and Sta. aureus. Sephadex G-200 gel chromatography showed only antibacterial activity from 33 to 37th fractions of 60 fractions. The agent purified from TLC plate confirmed the antibacterial activity by the means of bioautography.

• Journal of the Korean institute of surface engineering
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• v.29 no.1
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• pp.45-59
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• 1996

Ultrafine powders(UFPs) of aluminum nitride(AlN) have been synthesized by chemical reactions in the nitrogen atmosphere and the gaseous aluminum evaporated from Al powders in thermal plasmas produced by a DC plasma torch. A synthesis system consisting of a plasma torch, a finely-controllable powder feeder, a reaction chamber, and a quenching-collection chamber have been designed and manufactured, and a filter for gathering AlN UFPs produced by the quenching process subsequent to the synthesis is set up. The synthesis process is interpreted by numerical analyses of the plasma-particle interaction and the chemical equilibrium state, respectively, and a fully-saturated fractional factorial test is used to find the optimum process conditions. The degrees and ultrafineness of synthesis are evaluated by means of SEM, TEM, XRD, and ESCA analyses. AlN UFPs synthesized in the optimum process conditions have polygonal shapes of the size of 5-100 nm, and their purities differ depending on collecting positions and filter types, and the maximum purity obtained is 72 wt% at the filter.