• Environmental Mutagens and Carcinogens
• /
• v.16 no.1
• /
• pp.24-29
• /
• 1996

In this study, the micronucleus test with peripheral blood using acridine orange coated slides was evaluated in mice treated with mitomycin C(MMC) at doses of 0.5, 1.0 and 1.5 mg/kg body weight. The peripheral bloods were obtained at 0, 24, 48 and 72h after treatment. The frequencies of micronucleated reficulocytes(MNRET) in the MMC-treated groups increased dose-dependently, and showed a peak time at 48h after treatment. We also performed the sex differences of MNRET frequency in 0.5 mg/kg MMC treated group, and we observed no sex differences in this experiment. And we evaluated the usefulness of a direct acting clastogen, N-methyl-N-nitrosourea and a indirect acting clastogen, benzo(a) pyrene as the positive control in this supravital micronucleus test. They also caused a significant increase in MNRET frequencies. These results suggest that the supravital staining micronucleus test using MNRET can be useful tool to evalulate the quantitative and qualitative assessment of genotoxicity in vivo compared to classical in vivo micronucleus test using bone-marrow cells.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.64 no.4
• /
• pp.592-597
• /
• 2015

3D-IC is a novel semiconductor packaging technique stacking dies to improve the performance as well as the overall size. TSV is ideal for 3D-IC because it is convenient for stacking and excellent in electrical characteristics. However, due to high-density and micro-size of TSVs, they should be tested with a non-invasive manner. Thus, we introduce a TSV test method on test prober without a direct contact in this paper. A capacitive coupling effect between a probe tip and TSV is used to discriminate small TSV faults like voids and pin-holes. Through EM simulation, we can verify the size of eye-patterns with various frequencies is good for TSV test tools and non-contact test will be promising.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.61 no.4
• /
• pp.199-205
• /
• 2012

This paper propose a improved parameter estimations of five-phase squirrel-cage induction motor(IM) for speed control system on field oriented control(FOC). In order to high performance control of ac the motors using a FOC and DTC(direct torque control) algorithm, there are required precise motor parameters for slip calculation, flux observer, controller gain, rotor position and speed estimation, and so on. We are suggest a estimation method of the motor parameters that developing five-phase squirrel-cage IM have a stator of concentrated winding for experimental. There are results of stator winding test, no-load test, locked rotor test, and obtained equivalent circuits using manufactured experimental apparatus. For presenting the superior performance of the speed control system in adapted the parameters, experimental results are presented using a 32-bit fixed point TMS320F2812 DSP with 1.5[KW] IM.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.52 no.12
• /
• pp.671-678
• /
• 2003

This paper proposes an expert system to generate automatically the test table of test system which can highly enhance the quality and productivity of product by inspecting quickly and accurately the defect device on the electronic circuit board tested. The expert system identifies accurately the tested components and the circuit patterns by tracing automatically the connectivity of circuit from electronic circuit database. And it generates automatically the test table to detect accurately the missing components, the misplaced components, and the wrong components for analog components such as resistance, coil, condenser, diode, and transistor, based on the experience knowledge of veteran expert. It is implemented in C computer language for the purpose of the implementation of the inference engine using the dynamic memory allocation technique, the interface with the electronic circuit database and the hardware direct control. And, the validity of the builded expert system is proved by simulating for a typical electronic board model.

• Membrane Journal
• /
• v.27 no.3
• /
• pp.248-254
• /
• 2017

In order to secure the reliability of pathogenic microorganisms such as Cryptosporidium and Giaridia, which are chlorophilic protozoans, membrane filtration systems have been widely used in water purification process. hese integrity tests are classified into direct and indirect methods. Based on the bubble point theory, the pressure-based test in the direct method is presented in the USEPA Guidance Manual with sensitivity to detect a minimum size of pathogenic microorganisms of $3{\mu}m$ or more. Indirect methods are widely used in that they are capable of continuous operation in on-line state, but there is a very low sensitivity of damage detection compared to the direct method, and there is a limit that can not specify the damage area, so it is necessary to improve this sensitivity. In this study, we compared the LRVDIT and UCL values according to the type of membrane defect, number of fiber breaks, and initial set pressure value through the Integrity Test by Pressure Decay Test (PDT).

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.36 no.1
• /
• pp.143-149
• /
• 2016

This study evaluated the shear behavior of geogrid reinforced ballast material using a large scale direct shear test and discrete element method (DEM) based on PFC 3D program. The direct shear test was conducted on ballast materials that have different particle size distributions. Whereas the test results revealed that the shear strength generally increased with the larger particle size of ballast material without geogrid reinforcement, the shear behavior of ballast material was found to change pertaining to the relationship between particle size distribution and geogrid rib size. Generally, it is deemed the effectiveness of reinforcement can be achieved when the rib size is two times greater than average particle size. A numerical analysis based on DEM was conducted to verify the test results. The geogrid modeling was successfully completed by calibration process along with sensitivity analysis to have actual tensile strength provided by manufacturer. With a given geogrid model, the parametric evaluation was further carried out to examine the interactive behavior between geogrid and ballast material. Consequently, it was found that the effectiveness zone of geogrid reinforcement generated within a specific depth.

• Journal of Life Science
• /
• v.10 no.6
• /
• pp.630-639
• /
• 2000

The gastric pathogen Helicobacter pylori(H. pylori) establishes long-term chronic infection that can lead to atrophic gastritis, intestinal metaplasia, and gastric cancer. H. pylori, which express cytotoxic genes is now recohnized as a cause of peptic ulcer and is also a major risk factor for the development of gastric adenocarcinoma. We performed this study 1) to assess the detection rate of H. pylori according to direct investigation of bacteria of gastric biopsy specimen and two serologic tests of GAP test and Helico blot 2.0 system in the symptomatic and non-symptomatic group 2) to evaluate and compare the efficacy of two serologic tests of GAP test and Helico blot 2.0 system for the diagnosis of H. pylori infection. Forty-nine patients were positive for H pylori infection based on direct investigation of bacteria by histology. The detection rates of H. pylori infection based on direct investigation of bacteria by histology. The detection rates of H. phlori were significantly lower in gastric cancer than in other gastroduodenal disease(p<0.05). The concordance of two serologic tests of GAP test and Helico blot 2.0 system is poor. There was no statistically significant difference between the expression rate of CagA and VacA in the symptomatic and non-symptomatic group. Although Helico blot 2.0 system may not displace GAP test, it was a very sensitive serologic test for the diagnosis of H. pylori infection and it was used to detect IgG antibodies to H. pylori-specific antigens, including CagA, VacA and the various urease subunit. Our data suggest that further investigation is needed to determine whether or not the serologic expression of cytotoxic gene may be clinical usefulness of diagnostic methods in the gastroduodenal disease.

• Proceedings of the Korean Nuclear Society Conference
• /
• 2001.05a
• /
• pp.235.1-235
• /
• 2001

• 한국전산유체공학회:학술대회논문집
• /
• 1995.10a
• /
• pp.235-240
• /
• 1995

The paper describes hypersonic rarefied flow of helium and nitrogen over a flat plate by the direct simulation Monte Carlo (DSMC) method. The effect of incomplete accommodation and plate thickness are analyzed and the computational results are compared with wind tunnel test data. Also computational aspects of the method are outlined.

• The Journal of Engineering Geology
• /
• v.26 no.4
• /
• pp.447-460
• /
• 2016

Samples of Hangdeung granite and Berea sandstone containing sliding planes were prepared by saw-cutting and polishing using #100 or #600 grinding powders. Their basic friction angles were then measured directly in direct shear tests and triaxial compression tests, and also in tilt tests, which measure the angles indirectly. Although the angles measured by the direct methods were generally accurate, those measured along certain planes were greatly different from the others depending on the condition of the plane. The tilt tests yielded similar angles regardless of the sliding plane condition or the rock type; however, the error range was relatively wide. Sliding planes polished by the grinding powders yielded more accurate results than those cut by the saw and tested without polishing, as polishing ensured consistent conditions among all the planes. Sliding planes polished using #100 grinding powder yielded better results than polishing with #600 grinding powder. Therefore, the basic friction angles measured along the sliding planes polished using #100 grinding powder, as obtained in direct shear and triaxial compression tests, were the most reliable. The angle could also be measured satisfactorily by tilt testing along sliding planes polished with #100 grinding powder.