• Particle and aerosol research
• /
• v.6 no.2
• /
• pp.61-67
• /
• 2010

In this paper, we describe a new method to form polymer thin films, in which carbon nanotubes (CNTs) are homogeneously distributed so that they can strengthen the mechanical property of resulting polymer film. To do so, we first homogeneously mixed CNTs with polymer in a DMF solvent. With the assistance of ultrasonic nebulizer, the polymer/CNT solution was then aerosolized into micro-sized droplets and finally turned into solidified polymer/CNT composite particles by gas-phase drying process. As the results of SEM and TEM analysis, CNTs were found to be homogeneously immobilized in the polymer matrix particles due to rapid drying process in the gas phase. For comparison purpose, (i) the polymer/CNTs composite particles prepared by aerosol processing method and (ii) polymer/CNTs sheets prepared by simple solution-evaporation method were employed to form polymer/CNTs composite thin films using a hot press. As the result, the aerosol processing of composite particles was found to be a much more effective method to form homogeneously distributed-CNTs in the polymer matrix thin film.

• ETRI Journal
• /
• v.30 no.2
• /
• pp.183-193
• /
• 2008

In this paper, we propose quality of service mechanisms for flow-based routers which have to handle several million flows at wire speed in high-speed networks. Traffic management mechanisms are proposed for guaranteed traffic and non-guaranteed traffic separately, and then the effective harmonization of the two mechanisms is introduced for real networks in which both traffic types are mixed together. A simple non-work-conserving fair queuing algorithm is proposed for guaranteed traffic, and an adaptive flow-based random early drop algorithm is proposed for non-guaranteed traffic. Based on that basic architecture, we propose a dynamic traffic identification method to dynamically prioritize traffic according to the traffic characteristics of applications. In a high-speed router system, the dynamic traffic identification method could be a good alternative to deep packet inspection, which requires handling of the IP packet header and payload. Through numerical analysis, simulation, and a real system experiment, we demonstrate the performance of the proposed mechanisms.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.25 no.1
• /
• pp.47-53
• /
• 2001

Results ar presented of a new process for internal precision finishing of slender fine ceramic pipes using a magnetic field generated by a permanent magnets. For finishing the interior surface of a long pipe, a new type of finishing equipment was developed which can be very easily used in an industrial surrounding. In general, the pipe is so slender that a conventional finishing tool is hardly inserted into the pipe deeply, being impossible to finish. Therefore, a new technology has been considered to finish inside of a slender ceramic pipe by a simple technique. In this experimental, Magnetic Abrasive Machining is applied for the inner surface of silicon nitride fine ceramic pipe using ferromagnetic particles mixed with chromium-oxide powder. It is shown the initial roughness of 2.6㎛ Ry(0.42㎛ Ra) in the inside surface can be precisely finished to the roughness of 0.1㎛ Ry(0.01㎛ Ra). This paper discusses the outline of the processing by the application of magnetic abrasive machining and a few finishing characteristics.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.27 no.1
• /
• pp.95-104
• /
• 2003

The objective of this work is to investigate the turbulent reacting flow in a three dimensional combustor with emphasis on thermal NO emission through a numerical simulation. Flow field is analyzed using the SIMPLE method which is known as stable as well as accurate in the combustion modeling, and the finite volume method is adopted in solving the radiative transfer equation. In this work, the thermal characteristics and NO emission in a three dimensional combustor by changing parameters such as equivalence ratio and inlet swirl angle have investigated. As the equivalence ratio increases, which means that more fuel is supplied due to a larger inlet fuel velocity, the flame temperature increases and the location of maximum temperature and thermal NO has moved towards downstream. In the mean while, the existence of inlet swirl velocity makes the fuel and combustion air more completely mixed and burnt in short distance. Therefore, the locations of the maximum reaction rate, temperature and thermal NO were shifted to forward direction compared with the case of no swirl.

• Korean Journal of Food Science and Technology
• /
• v.52 no.5
• /
• pp.482-486
• /
• 2020

Cases of inflammatory bowel diseases including ulcerative colitis are increasing in Korea and development of non-steroidal anti-inflammatory drugs (NSAIDs) are widely investigated. Natural products with anti-inflammatory properties are rising as safe candidates for NSAIDs. The extract of turmeric or puffed turmeric mixed with herbal extract (goji berry, liquorice, lycium root, and dong quai) was treated to acute colitis mice by oral gavage. The symptoms of colitis, i.e., body weight loss, fecal score, and shortened colon length, were significantly attenuated by puffed turmeric extract with the herbal extract. Non-puffed turmeric extract with herbal extract, however, exhibited a very marginal recovery. Tissue culture supernatant of colons further revealed that both puffed turmeric and non-puffed turmeric extracts with herbal extract suppressed pro-inflammatory cytokine production at a comparable level. These results indicate that puffing is a simple and promising process of turmeric for enhancement of anti-inflammatory properties.

• The Journal of the Korean Society for Microbiology
• /
• v.11 no.1
• /
• pp.79-85
• /
• 1976

There are many of anaerobic culture methods and equipments for isolation and cultivation of anaerabic bacteria, but most of these methods are used without pre-reduced media. Gas-jet method is a recommend. able method for the culture of anaerobes, resently developed. Bacteriological studies were experimented of liver abscess of cattle by the use of gas. jet method. The results were summarised as follows; 1. Gas-jet method for anaerobic culture are expedient for the making of pre-reduced media, maintaining of oxygen free condition in the culture tube, picking of bacteria from colony and colony counting etc. 2. A 121 strains of facultative anaerobic and anaerobic bacteria were isolated from liver abscess of 27 head of cattle, and the isolated anaerobic bacteria were as follows. Peptostreptococcus spp. 7 strains Acid aminococcus fermentans 1 Veillonella spp. 1 Bacterioides spp. 6 Bifidobacterium spp. 4 Arachinia propionica 2 Lactobacillus spp. 4 Propionibacterium acnes 1 3. Liver abscess were infected with many of bacteria, about $10^3-10^9$ numbers per gram of abcessed tissue. Almost of abscess were mixed infection of various bacterial species rather than simple species.

• Journal of the Korean Society of Tobacco Science
• /
• v.1 no.1
• /
• pp.33-38
• /
• 1979

A simple test using latex-agglutination was developed to detect serologically tobacco mosaic virus (TMV), soybean mosaic virus (SoyMV), and barley stripe mosaic virus (BSMV) from infected Plants. Latex spheres ( 0.81 $\mu$, Difco) were adsorbed with immuno globulin purified by electrophoresis from crude antiserum against viruses. The antibody- sensitized latex suspension was mixed with sap from virus -infected leaves in a glass capillary tube (inner diam. 1mm $\times$ 100 mm length) The mixture, after agitation, was observed under a stereo microscope at low magnification (X20 - X4O), to examine the reaction between antigen (Virus) and its antibody. Flocculation occurred when the reaction was positive.

• Korean Journal of Materials Research
• /
• v.15 no.5
• /
• pp.285-292
• /
• 2005

Anti-reflection film was coated by using spherical silica nano colloids. Silica colloid sol was reserved between two inclined slide glasses by capillary force, and particles were convectively stacked to form a film onto the substrate as the water evaporates. As the sliding speed increased, the thickness of the film decreased and the wavelength at the maximum transmittance decreased. The microstructure observed by SEM showed that silica particles were nearly close packed, which enabled the calculation of the effective refractive index of the film. The film thickness was measured by proffer and calculated from the wavelength of maximum transmittance and the effective refractive index. The effective refractive index of the film could be controlled by a subtle controlling of the coating speed and by mixing two different sized silica particles. When the 100 nm and 50 m particles were mixed at 4:1-5:1 volume ratio, the maximum transmittance of $95.2\%$ for one-sided coating was obtained. This is the one that has increased by $3.8\%$ compared to bare glass substrate, and shows that $99.0\%$ of transmittance or $1.0\%$ of reflectance can be achieved by the simple process if both sides of the substrate are coated.

• Korean Journal of Materials Research
• /
• v.17 no.12
• /
• pp.637-641
• /
• 2007

The total energy and strength of Mg alloy doped with Al, Ca and Zn, were calculated using the density functional theory. The calculations was performed by two programs; the discrete variational $X{\alpha}\;(DV-X{\alpha})$ method, which is a sort of molecular orbital full potential method; Vienna Ab-initio Simulation Package (VASP), which is a sort of pseudo potential method. The fundamental mixed orbital structure in each energy level near the Fermi level was investigated with simple model using $DV-X{\alpha}$. The optimized crystal structures calculated by VASP were compared to the measured structure. The density of state and the energy levels of dopant elements was discussed in association with properties. When the lattice parameter obtained from this study was compared, it was slightly different from the theoretical value but it was similar to Mk, and we obtained the reliability of data. A parameter Mk obtained by the $DV-X{\alpha}$ method was proportional to electronegativity and inversely proportional to ionic radii. We can predict the mechanical properties because $\Delta{\overline{Mk}}$is proportional to hardness.

• Proceedings of the KSRS Conference
• /
• 2005.10a
• /
• pp.422-425
• /
• 2005

Spectral characteristics depending on soil constituents and their proportion in a soil were firstly studied for monitoring of soil contamination using hyperspectral remote sensing. The reflectance spectra of heavy metals in soils were investigated in the VIS-NIR-SWIR regions (400-2500 nm) to observe spectral variation as a function of constituents and concentrations. Commercial kaolinite soils mixed with lead, copper, arsenic, and cadmium were used as synthetic soil samples for spectral measurement. In case of copper, relatively spectrally active regions was observed with some band shift whereas other heavy metals had only simple spectral variations expected to be related to the sorption phase and the amount of metal onto kaolinite. The reflectance spectrum of each metal on kaolinite could be identified in VIS-NIR region.