• Journal of Korean Society of Environmental Engineers
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• v.35 no.2
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• pp.137-143
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• 2013

This study is to develop the production method of stepwise dilution gas for the evaluation of complex odor concentration by orifice tube. The basic orifice tube for 10 and 30 times of dilution sample was made at first, and with the combination of the basic orifice tubes we can continuously manufacture the stepwise dilution sample gas for air dilution sensory test ; 10, 30, 100, 300, 1,000, 3,000 times etc. The hole size of orifice tube was 0.84 mm for 10 times of dilution sample, and was 0.34 mm for 30 times. Dilution sample gas made with the basic orifice tube have an excellent reproducibility, 2%RSD. In addition, over 90% of correlation was shown between the sample made by the orifice tube and the sample by the syringe dilution method. Because there was no concentration drift of dilution gas with changes of connected pump flow, the basic orifice tube could be mounted directly with a vacuum suction box, and could be used simply as a tool for the evaluation of odor, especially on site.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.5
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• pp.67-73
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• 2009

Recently, Europe decided to start the regulation of diesel engine nanoparticles because of its well known adverse health effects. The diesel nanoparticles can be classified as solid carbon particles and volatile particles. The volatile particles generates during dilution process by condensation of gas phase volatile compounds such as hydrocarbon. The new nanoparticle regulation considers only solid particles because of difficulty of measurement of volatile particles. The aim of this study is to suggest a proper dilution method that prevent the volatile particle generation. As a result, it is found that the $1^{st}$ dilution air temperature should be above $120^{\circ}C$ in order to prevent volatile particle generation effectively. It is also found that the volatile particles can be removed effectively in the evaporation tube by the increase of evaporation tube temperature. But when exhaust gas is hot enough (>$190^{\circ}C$, in this study) and it is diluted in the first diluter with high temperature air (>$120^{\circ}C$), removal phenomenon of volatile particles by increasing of evaporation tube temperature can not be seen. It means that there are no volatile particles in the diluted exhaust gas. Additionally, dilution ratio is not an important factor for volatile particle generation compared with dilution air temperature or evaporation tube temperature.

• Fashion & Textile Research Journal
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• v.5 no.1
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• pp.71-76
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• 2003

Three different types of chitosan were prepared from red crab shells to study anti-microbial activity of chitosan on pathogenic bacteria, MRSA(Methicillin-resistant. Staphylococcus aureus), Water-insoluble chitosan, whose degree of deacetylation is kept over 90% and molecular weights are 20,000, 500,000, 150,000, 80,000, and 40,000, respectively. Water-soluble chitosan, whose degree of deacetylation is about 48% and molecular weights are 200,000 and 80,000. Water-soluble chitosan, whose degree of deacetylation is 82% and molecular weight is 3,900. The anti-microbial activities of three types of chitosan were investigated by Tube Dilution Technique(TDT) and Agar Plate Smear Method(APSM). And the following conclusions are made ; Chitosan having 5 different types of M.W chitosan (over 90% deacetylation) showed similar anti-microbial activities at over 0.05% concentration. Especially, chitosan having M.W 40,000 150,000 showed the excellent anti-microbial activity. The anti-microbial activity of chitosan was enhanced when the chitosan/acetic add solution was aged for 7days. The anti-microbial activity of chitosan was only shown at chitosan/acetic acid solution. The anti-microbial activity was not detected in chitosan solution dissolved in neutral pH water. Therefore, it can be concluded that the anti-microbial activity was due to NH3+ cationic ion of chitosan in acidic aqueous solution.

• Korean Journal of Veterinary Service
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• v.21 no.2
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• pp.107-115
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• 1998

In order to establish a rapid, sensitive and specific diagnostic method for detection of antibody to Brucella abortus, a enzyme-linked immunosorbent assay(ELISA) was adapted. The diagnostic efficacy of the established ELISA was compared with that of the standard tube agglutination test for B abortus. 1. It was found that the optimal concentration of antigen for this ELISA was 5$\mu\textrm{g}$/ml, the optimal dilution of conjugate was 1 : 2000, and the optimal dilution of serum was 1 : 200, respectively. 2. Cut off value in this ELISA was 1,102 that was determined by mean absorbance(at 492nm) of tube agglutination test negative serum added with the triple value of the standared devation. 3. The relationship between the tube agglutination test and ELISA was showen high corresponding rate with sensitivity(96.3%) and specificity(98.1%). 4. The efficacy of the ELISA for detection of B abortus antibody was compared with tube agglutination test In brucellosis outbreak farm. The sensivity of ELSIA was higher than tube agglutination test.

• The Journal of the Korean Society for Microbiology
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• v.9 no.1
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• pp.25-31
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• 1974

A comparative study was performed with 176 cultures of Salmonella organisms on tetracyline, neomycin and colistin in order to find out the relationship between the results obtained from the Ericsson's single disk method and the tube dilution method of antibiotic sensitivity tests which may be carried out in many hospital laboratories. With tetracycline, thirty-three out of 163 cultures of Salmonella typhi were found to be either sensitive or moderate sensitive by means of the disk method and thirty one(ca 94%) out of the thirty three cultures showed less than 1.0 ${\mu}g$ of the Minimal Inhibitory Concentretions(MIC) in the tube-dilution tests, which mean that there were a quite good agreement between the two methods. With neomycin, a hundred and five out of 163 S.typhi were appeared to be either sensitive or moderate sensitive by means of Ericsson's single disk method, among which 103 cultures showed less than 10.0 ${\mu}g$ MIC in the tubedilution method. And also there was a quite correlative pat. terns observed in the result of testing with 13 salmonella cultures other than S. typhi. With colistin, it was hard to observe any particular tendency in the distribution of plotting for 148 cultures showing less the 18 mm in the inhibiting zone diameters between MIC and disk sensitivity patterns except the fifteen, cultures out of 176 salmonella, which appeared to be sensitive in the single disk method and showed less than 1.0 ${\mu}g$ MIC in the tube dilution method.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.12
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• pp.1734-1743
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• 2003

Aerosol generator using an electrically heated tube furnace is a stable apparatus to supply nanometer sized aerosols by using the evaporation and condensation processes. Using this method, we can generate highly concentrated polydisperse aerosols with relatively narrow size distribution. In this work, characteristics of particle size distribution, generated from a tube furnace, were experimentally investigated. We evaluated effects of several operation parameters on particle generation: temperature in the tube furnace, air flow rates through the tube, size of boat containing solid sodium chloride(NaCl). As the temperature increased, the geometric mean diameter increased and the total number concentration also increased. Dilution with air affected the size distribution of the particles due to coagulation. A smaller sized boat, which has small surface area to contact with air, brings smaller particles of narrow size distribution in comparison of that of a larger boat. Finally, we changed the electrical mobility diameter of aggregate sodium chloride particles by varying relative humidity of dilution air, and obtained non-aggregate sodium chloride particles, which are easy to generate exact monodisperse particles.

• The Journal of the Korean Society for Microbiology
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• v.22 no.3
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• pp.301-307
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• 1987

A total of 42 strains of Candida albicans were examined for susceptibility to three antifungal agents, amphotericin B(AMB), 5-fluorocytosine(5-FC), and ketoconazole(KTZ), using defined medium, synthetic amino acid medium-fungal(SAAM-F), supplemented yeast nitrogen base(SYNB) and undefined medium Sabouraud's dextrose broth(SDB) and Kimmig broth media. A tube dilution method was used with minimum inhibitory concentrations(MICs) determined after incubation for 24 hour and 48 hours. All testes were performed in duplicate. In general, MICs were more reproducible after 48 hour of incubation. Forthermore, MICs determined after incubation for 48 hours were significantly higher than those determined after 24 hours. The actural MICs obtained with the different antifungal agents were clearly influenced by the test medium used. The rank order of AMB MICs according to the test medium was as follows: SAAM-F>SYNB>SDB>Kimmig broth. With 5-FC, the following pattern was observed: SYNB>SAAM-F>SDB>Kimmig borth. For ketoconazole, the MICs according to the test medium was SAAM-F>SDB>SYNB> Kimmig broth. In amphotericin B, the MICs mean value with the test medium was as follows: SDB, 0.24 mcg/ml; Kimmig broth, 0.29 mcg/ml; SYNB, 0.21 mcg/ml and SAAM-F, 0.15mcg/ml. The actural value of 5-FC was; SDB, 37.20 mcg/ml; Kimmig broth, 67.41mcg/ml; SYNB, 21.29 mcg/ml and SAAM-F, 24.61 mcg/ml and in ketoconazole, the MICs value was; SDB, 1.83 mcg/ml; Kimmig broth, 4.08 mcg/ml; SYNB, 1.95 mcg/ml and SAAM-F, 1.41 mcg/ml. The results of this investigation suggested that broth dilution susceptibility testing of yeast and yeast-like fungi are best performed with an incubation period of 48 hours. Furthermore, medium composition can significantly influence the results of such testing.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.10
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• pp.639-647
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• 2017

This basic study is focused on the physically removal method of carbon dioxide from the decomposition of ammonium carbarmate to prevent the recombination of ammonium salts. A basic visual experimental set-up was designed and constructed to observe the recombination phenomena from the proper composition of ammonia gas, carbon dioxide gas, and compressed air dilution gas. To quantify the recombination phenomena, a simple device was designed to measure the weight change under severe cases for three different tube sizes. The temperature and pressure in the visual tube and the volumetric flow rates of the nitrogen dilution gas were studied and the conditions to avoid recombination were analyzed according to mean free path theory. Diffusivity values based on the Chapman-Enskog theory were calculated from the experimental data. These value may serve as an index for the prevention of recombination.

• YAKHAK HOEJI
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• v.9 no.1_2
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• pp.8-13
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• 1965

The sensitivity on microorganisms of ten sulfa-drugs and their Cu-complexes was observed. Ericsson's disc method and modified tube dilution method were applied. Dimethylformamide was used for solvent of sulfa drugs. In general, original sulfa-drugs showed more sensitive patterns than its Cu-complexes except sulfadimethoxine-Cu complex which showed more sensitive patterns than its original drug with disc method.

• Progress in Superconductivity and Cryogenics
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• v.24 no.2
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• pp.1-6
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• 2022

This paper reviews the literature that has been published since 1980s related to cryogenic refrigeration systems for quantum computing. The reason why such a temperature level of 10-20 mK is necessary for quantum computing is that the superconducting qubit is sensitive to even very small thermal disturbances. The entanglement of the qubits may not be sustained due to thermal fluctuations and mechanical vibrations beyond their thresholds. This phenomenon is referred to as decoherence, and it causes an computation error in operation. For the stable operation of the quantum computer, a low-vibration cryogenic refrigeration system is imperative as an enabling technology. Conventional dilution refrigerators (DR), so called 'wet' DR, are precooled by liquid helium, but a more convenient and economical precooling method can be achieved by using a mechanical refrigerator instead of liquid cryogen. These 'dry' DRs typically equip pulse-tube refrigerators (PTR) for precooling the DRs around 4 K because of its particular advantage of low vibration characteristic. In this review paper, we have focused on the development status of 4 K PTRs and further potential development issues will be also discussed. A quiet 4 K refrigerator not only serves as an indispensable precooler of DR but also immediately enhances the characteristics of low noise amplifiers (LNA) or other cryo-electronics of various type quantum computers.