• Journal of the Korean Society for Precision Engineering
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• v.21 no.10
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• pp.34-41
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• 2004

A new method to fabricate the fine magnetic abrasives by using mechanical alloying is proposed. The mechanical alloying process is a solid powder process where the powder particles are subjected to high energetic impact by the balls in a vial. As the powder particles in the vial are continuously impacted by the balls, cold welding between particles and fracturing of the particles take place repeatedly during the ball milling process using a planetary mill. After the manufacturing process, fine magnetic abrasives which the guest abrasive particles c lung to the base metal matrix without bonding material can be obtained. The shape of the newly fabricated fine magnetic abrasives was investigated using SEM and its polishing performance was verified by experiment. It is very helpful to finishing the injection mold steel in final polishing stage. The areal ms surface roughness of the workpiece after several polishing processes has decreased to a few nanometer scales.

• Journal of the Korean Wood Science and Technology
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• v.37 no.5
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• pp.440-450
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• 2009

In case of wood flooring, the high emissivity would be one of the most important properties especially as the cover material of underfloor heating system. The FIR (Far Infrared) materials such as wood emit FIR energy by heating, which has been used as the medical therapy such as dry sauna. This research investigated the emissivity and the emission power of wood composites by comparing the amount of the three heat transfer modes transferred by infrared radiation which came from the increased temperature of the bottom board of the plywood box by the heater. The results showed the value of radiation mode was the highest mode for the plywood box, and the convection mode was the main mode for the aluminum box. The rate of convection was 81.8% in the aluminum box and 48.2% in the plywood box, respectively. In case of the rate of radiation, the aluminum box showed only 15.4% and the plywood box showed 51%. The emissivity and the emission power of birch plywood showed the same values as those of wood. The amount of energy required for the temperature rising of water within vial in the aluminum box and in the plywood box were 3.32 kJ and 6.70 kJ respectively, which showed that the vial temperature of the plywood box was two times higher than that of the aluminum box.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.2 no.2
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• pp.108-113
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• 2021

Detrimental effects of inbreeding have been studied by many researchers for a long time. However, only a few studies have shown the occurrence of inbreeding depression due to evolutionary changes as a purging process. In this study, two different populations (inbreeding and outbreeding) of Drosophila melanogaster were compared to assess inbreeding effects on artificial population bottlenecks. For inbreeding conditions, a couple of D. melanogaster (one virgin and one male) were selected from an inbred population and cultured in a vial. For outbreeding conditions, a couple of D. melanogaster were selected from different populations and cultured in a vial. There were significant differences in body lengths of adults, but not in other parameters such as the total number of adults, the rate of survival, and the rate of wing mutants. The mean body length of adults of outbreeding populations was longer than that of inbreeding populations in the first generation (G1; P = 0.004), but not in the second generation (G2; P = 0.066). Although the other three parameters (total number of adults, rate of survival, and rate of wing mutants) showed differences in their mean values between inbreeding and outbreeding populations, these differences were not statistically significant. This might be due to genetic purging. This study demonstrated one additional experimental case related to inbreeding depression in artificial bottlenecked populations. Further studies are necessary to confirm the clear interaction between inbreeding depression and genetic purging using more generations and replicates (or samples) of D. melanogaster.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.3
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• pp.156-158
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• 2009

Purpose: Since radiopharmaceuticals are intended for human administration, it is imperative that we should undergo quality control very strictly. Now almost all the PET laboratories have adopted Bacterial Endotoxin Test as the stand quality control method to monitor whether pyrogen is free or not in the product vial containing crude solution. The aim of this study is to find out the reason why false positive result is observed when using commercially available test vial. Materials and Methods: For this experiment, we used commercially available single test kit (Associates of Cape Code. Inc. USA) and we made pH samples by mixing each buffer whose pH ranges are 1.0 to 12.0. Otherwise we made Ethanol samples diluted with distilled water. After making test samples, it added 0.2 mL to the test vial. Assay mixture in the test vial was incubated in a water bath (Chang Shin Co. KOR) for 60 min at $35{\pm}2^{\circ}C$. Results: After incubation period ($60{\pm}1^{\circ}C$), we inverted the test vial about $180^{\circ}$ To know what pH and how many percentage of Ethanol (Fisher Scientific Korea. Ltd) will affect the reaction. With pH buffer, false positive result was observed at pH 1.0 to 5.0 and 7.7 to 12.6 but at pH 5.2 to.7.5, the test results show negative. It's very strange that we couldn't observe negative test result with Tris buffer at pH 8.4, 8.6, 8.8, 9.0. in other case Ethanol, the test result was seen with 5 to 10% Ethanol. But to my surprise we could see very thick gel formation with 100% Ethanol. Conclusions: In this study, we could notice that pH which is too much acidic or alkalic or high concentrated Ethanol would affect Bacterial Endotoxin Test result. As you know, LAL test is sensitive and very reliable method. Therefore, we are needed to elicit the accurate test result as possible as we can.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.2
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• pp.203-207
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• 2010

Purpose: Hepatitis B is infection caused by Hepatitis B virus (HBV). Currently, there are several methods, Kits and equipments for conducting Hepatitis B test. Due to ununiformed methods, it would cause some differences. To manage these differences, it needs process evaluating function of test system and reagent using particular standard substance. The aim of this study is to investigate tendency of RIA method's reagent used in Asan Medical Center through comparing several other test reagents using national standard substance. Materials and Methods: The standard substance in National Institute of Food and Drug Safety Evaluation's biology medicine consists of 5 things, 4 antigens and 1 antibody. We tested reagents using A, B company's Kits according to each test method. All tests are measured repeatedly to obtain accurate results. Results: Test result of "HBs Ag Mixed titer Performance panel" is obtained match rate compared S/CO unit standard with RIA method and EIA 3 reagents, CIA 2 reagents is that company A's reagent is 94.4% (17/18), 83.3% (15/18), B is 88.9% (16/18), 77.8% (14/18). Test result of "HBs Ag Low titer Performance panel" is obtain that EIA 2 reagents is shown 7 posive results, CIA 3 reagents is 11, and RIA method's company A's reagent is 3, B is 2 of 13 in low panel. "HBV surface antigen 86.76 IU/vial" tested dilution. A is obtain positive results to 600 times(0.14 IU/mL), B is 300 times (0.29 IU/mL). Case of "HBV human immunoglobulin 95.45 IU/vial", A is shown positive result to 10,000 times (9.5 mIU/mL) and B is 4,000 times (24 mIU/mL). Test result of "HBs Ag Working Standards 0.02~11.52 IU/mL" is shown that Company A's kit concentration level was 0.38IU/mL, company B was 2.23 IU/mL and higher level of concentration was positive results. Conclusion: When comparing various test reagents and RIA method according to National Standard substances for Hepatitis B test, we recognized that there were no significant trends between reagents. For hepatitis B virus antigen-antibody titers even in parts of the test up to 600 times the antigen, antibodies to 10,000 times the maximum positive results could be obtained. Therefore, we confirmed that results from Asan Medical Center are performed smoothly by reagents and system for hepatitis B virus test.

• Analytical Science and Technology
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• v.12 no.5
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• pp.428-435
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• 1999

A method for measuring Rn-222 and Ra-226 in aqueous sample using liquid scintillation counting technique has been studied. The Rn-222 was extracted easily from the water sample (10 mL) by 12 mL of xylene based organic scintillant. After radioactive equilibrium between Rn-222 and its alpha emitting decay products for three hours, the alpha activity from Rn-222 and its decay products were measured in a scintillation vial using the Wallae $1220^{TM}$ Quantulus liquid scintillation counter. Ra-226 concentration in aqueous sample was determined, after isolation of Ra-226 from the sample matrix, by extraction the ingrowth of the Rn-222 and its alpha emitting decay products with xylene based organic scintillant. The optimum pulse-shape analysis (PSA) value was evaluated by the figure of merit (FM) criterion. Minimum detectable activity (MDA) is about 0.14 Bq/L (3.78 pCi) for the region of Rn-222 and its alpha emitting decay products and 0.06 Bq/L (1.63 pCi) for the region of Po-214 respectively, with 200 min, counting time at PSA level 100 in the low-diffusion polyethylene vial and xylene based cocktail solution. Experiment on the optimum sample-cocktail volume ratio, the influence of agitation and the diffusion of radon from vial were carried out.

• Journal of Embryo Transfer
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• v.15 no.3
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• pp.295-302
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• 2000

The objective of this study was to compare different superovulation treatments using PMSG or PG600$^{ }$ and to determine the optimal time of oocyte recovery after hCG administration. A total of 90 prepubertal Yorkshire x Landrace gilts crossed with Duroc, 6~7 months old and 100~120 kg of body weight, were used. PMSG (1,500 IU/head) or 5~7.5 ml of PG600$^{ }$(400 IU of PMSG and 200 IU of hCG) were administrated subcutaneously, and then 1,000 IU of hCG were administered intramuscularly at 72 hours after PMSG or PG600$^{ }$ injection. At carious time of 44, 46, 48 and 50 hours after hCG injection, superovulated gilts were slaughtered in a local abattoir. Ovaries together with oviducts were excised from the body immediately after slaughtered and transported to laboratory in 39$^{\circ}C$ saline. Ovaries were examined fur the number of corpus hemorrhagicum and unovulated follicles present in the surface of ovary. The unovulated follicles were categorized into small (1~3 mm in diameter) and large (4~8 mm) groups according to their diameter. Oocytes were recovered by flushing both oviducts with micropipette tip (1~100 $\mu$l) attached to a 10-ml disposable syringe. The number of CH on ovary and recovered oocytes at 46, 48 and 50 hr after hCG injection in PG600$^{ }$ treated groups were significantly higher than the other group. Group of phCG 50 hr among PMSG treated groups had a greater number of CH and recovered oocytes(P<0.05). The number of CH on ovary and recovered oocytes at 50 hr after hCG injection in 1$\frac{1}{2}$ vial(7.5 ml) of PG600$^{ }$ treated groups was significantly higher than 1 vial(5 ml) of PG600$^{ }$ treated group(P<0.05). In conclusions, considering a number of corpus hemorrhagicum and recovered oocytes after superovulation in gilts, effective time of oocyte recovery by treatment with PMSG and hCG was post-hCG 50 hr and with PG600$^{ }$ plus hCG was post-hCG 46, 48 and 50 hr. Also, admini-stration of 1$\frac{1}{2}$ vial(7.5 ml) of PG600$^{ }$ treated group had a great number of CH and recovered oocytes.covered oocytes.

• Journal of Korean Medicine Rehabilitation
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• v.26 no.2
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• pp.51-59
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• 2016

Objectives We studied long-term preservation in stability of a mixed preparation of distilled and 70% alcohol extracted Hwangnyunhaedok-tang pharmacopuncture to establish standards for expiration date and quality control. Methods Three lots of consecutively prepared Hwangnyunhaedok-tang pharmacopuncture were each tested in triplicate to a total 5 tests at 3 month intervals over a period of 12 months for analysis of appearance, pH, specific gravity, index component content, endotoxins, microbial sterility, residual organic solvents, heavy metals, and pesticides. Items with no difference by elapsed time were tested at the initial and final timepoints, and data of items with potential difference by elapsed time were analyzed for trends to establish individual quality control standards. Results All tested items were stable over the study period, and therefore the expiration date was set as 12 months. pH quality control standards were set as 3.66~5.69, and that of specific gravity as 0.802~1.203, respectively. In index component content standards, berberine was set at $4.96{\sim}8.98{\mu}g/vial$, baicalin at $6.47{\sim}10.31{\mu}g/vial$, and geniposide at $116.03{\sim}189.55{\mu}g/vial$, respectively. Standards for other items with no difference by elapsed time were set according to general Korean herbal medicine standards in the Korean Pharmacopoeia. Conclusions Manageable expiration date and quality control standards were established through long-term preservation testing of Hwangnyunhaedok-tang pharmacopuncture, furthering standardization of Korean medicine pharmacopuncture.

• Journal of Radiation Protection and Research
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• v.20 no.2
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• pp.103-115
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• 1995

For the determination of $^{222}Rn$ in water by a very simple and time saving liquid scintillation counting method that does not require any chemical separation, an optimum analytical condition has been investigated. The optimum pulse shape analysis(PSA) level for the measurement of $^{222}Rn$ using LKB 1220 Quantulus liquid scintillation counter was 110 for Optiphase HiSafe3 cocktail and 90 for toluene-based cocktail. The counting efficiencies of $^{222}Rn$ in the window covering u spectra using Optiphase HiSafe3 cocktail were 282.2% for glass vial and 271.6% for Teflon vial, whereas the counting efficiencies in toluene-based cocktail were 262.3% and 247.5% for glass and Teflon vials, respectively. The minimum detectable activity(MDA) in the u window for a 60-min measurement with a Teflon vial using Optiphase HiSafe3 cocktail was $0.30Bq/{\iota}$. The analytical method studied from this work was also applied to the determination of $^{222}Rn$ in some groundwater and hot spring water samples.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.350-353
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• 2004

in order to develop a new technique for the removal of arsenic compoundsfrom acidified water, the removal of arsenic compounds by an acidophilic moss, Jungermannia vulcanicola Steph. was investigated in this study. The result of vial tests for arsenic removal is dependent on the biological activity of moss. The presence of phosphate inhibited the arsenic removal. And the acclimatization of moss by the media containing arsenic increased the its capability of arsenic remova.