• Textile Coloration and Finishing
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• v.15 no.1
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• pp.48-55
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• 2003

As the polyester fiber becomes thinner, thermomigration that is the most important factor deteriorating the washfastness, is more dominant. For improving the washfastness of ultrafine polyester dyed with disperse dye, it is necessary either to decrease the amount of thermomigrated dyes on the fiber surface, or to use a disperse dye containing diester group in the coupling component. This paper is concerned to investigate the relation between the chemical structure of three disperse dyes and their dyeing properties and washfastness. The disperse dye whose molecular size is big, can dye ultrafine polyester with good build-up, and its washfastness is reasonably good. Other disperse dye which has diester group, shows the same dyeing properties as the standard disperse dye, and its washfastness is better than that of the standard disperse dye.

• IMMUNE NETWORK
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• v.12 no.3
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• pp.104-112
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• 2012

Silica is one of the most abundant compounds found in nature. Immoderate exposure to crystalline silica has been linked to pulmonary disease and crystalline silica has been classified as a Group I carcinogen. Ultrafine (diameter <100 nm) silica particles may have different toxicological properties compared to larger particles. We evaluated the effect of ultrafine silica nanoparticles on mouse bone marrow-derived dendritic cells (BMDC) and murine dendritic cell line, DC2.4. The exposure of dendritic cells (DCs) to ultrafine silica nanoparticles showed a decrease in cell viability and an induction of cell death in size- and concentration-dependent manners. In addition, in order to examine the phenotypic changes of DCs following co-culture with silica nanoparticles, we added each sized-silica nanoparticle along with GM-CSF and IL-4 during and after DC differentiation. Expression of CD11c, a typical DC marker, and multiple surface molecules such as CD54, CD80, CD86, MHC class II, was changed by silica nanoparticles in a size-dependent manner. We also found that silica nanoparticles affect inflammatory response in DCs in vitro and in vivo. Finally, we found that p38 and NF-${\kappa}B$ activation may be critical for the inflammatory response by silica nanoparticles. Our data demonstrate that ultrafine silica nanoparticles have cytotoxic effects on dendritic cells and immune modulation effects in vitro and in vivo.

• Nuclear Engineering and Technology
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• v.55 no.8
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• pp.2785-2796
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• 2023

How to generate the precise broad group cross section is important for the fast reactor design. In this study, a fast reactor multi-group cross-section generation code MGGC2.0 are developed in-house for processing ultrafine group MATXS format library. Validation and verification are performed for MGGC2.0 code by applying the benchmarks of ICSBEP handbook, and the results of MGGC2.0 agree well with that of MCNP. The consistent P_N method with critical buckling search is in good agreement that condensed with TWODANT flux and flux moment for the inner core and outer core region. For the radial blanket and reflector, two region approximation method has been applied in MGGC2.0 by using collision Probability Method neutron flux solver. The RBEC-M benchmark was used to verify the power distribution calculation, and the relative error of power distribution comparison with the reference are less than 0.8% in the fuel region and the maximum relative error is 5.58% in the reflector region. Therefore, the precise broad cross section can be generated by MGGC2.0 for fast reactor.

• Nuclear Engineering and Technology
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• v.50 no.3
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• pp.340-355
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• 2018

The methods and performance of a fast reactor multigroup cross section (XS) generation code EXUS-F are described that is capable of directly processing Evaluated Nuclear Data File format nuclear data files. RECONR of NJOY is used to generate pointwise XS data, and Doppler broadening is incorporated by the Gauss-Hermite quadrature method. The self-shielding effect is incorporated in the ultrafine group XSs in the resolved and unresolved resonance ranges. Functions to generate scattering transfer matrices and fission spectrum matrices are realized. The extended transport approximation is used in zero-dimensional calculations, whereas the collision probability method and the method of characteristics are used for one-dimensional cylindrical geometry and two-dimensional hexagonal geometry problems, respectively. Verification calculations are performed first for various homogeneous mixtures and cylindrical problems. It is confirmed that the spectrum calculations and the corresponding multigroup XS generations are performed adequately in that the reactivity errors are less than 50 pcm with the McCARD Monte Carlo solutions. The nTRACER core calculations are performed with the EXUS-F-generated 47 group XSs for the two-dimensional Advanced Burner Reactor 1000 benchmark problem. The reactivity error of 160 pcm and the root mean square error of the pin powers of 0.7% indicate that EXUF-F generates properly the broad-group XSs.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.1080-1083
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• 2001

Ultrafine NiO/YSZ composite powders were prepared by using a glycine nitrate process for anode material of solid oxide fuel cells. The specific surface areas of synthesized NiO/YSZ composite powders were examined with controlling pH of a precursor solution and the content of glycine. The characteristics of synthesized composite powders were examined with X-ray diffractometer, a BET method with N$_2$absorption, scanning and transmission electron microscopy. The strongly acid precursor solution increased the specific surface area of the synthesized composite powders. This is suggested to be caused by the increased binding of metal ions and glycine under a strong acid solution of pH=0.5 that lets glycine consist of mainly the amine group of NH$_3$$\^$+/. After sintering and reducing treatment of NiO/YSZ composite powders synthesized by GNP, the Ni/YSZ pellet showed ideal micro-structure very fine Ni parties of 3-5${\mu}$m were distributed uniformly and fine pores around Ni metal particles were formed, thes, leading to an increase of the triple phase boundary among gas Ni and YSZ.

• Journal of Powder Materials
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• v.16 no.2
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• pp.98-103
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• 2009

The ultrafine titanium carbonitride particles ($TiC_{0.7}N_{0.3}$) below 100nm in mean size were successfully synthesized by Mg-thermal reduction process. The nanostructured sub-stoichiometric titanium carbide ($TiC_{0.7}$) particles were produced by the magnesium reduction at 1123K of gaseous $TiC_{l4}+xC_2Cl_4$ and the heat treatments in vacuum were performed for five hours to remove residual magnesium and magnesium chloride mixed with $TiC_{0.7}$. And final $TiC_{0.7}N_{0.3}$ phase was obtained by nitrification under normal $N_2$ gas at 1373K for 2 hrs. The purity of produced $TiC_{0.7}N_{0.3}$ particles was above 99.3% and the oxygen contents below 0.2 wt%. We investigated in particular the effects of the temperatures in vacuum treatment on the particle refinement of final product.

• Journal of Powder Materials
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• v.19 no.5
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• pp.338-342
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• 2012

A novel chemical method was evaluated to fabricate the ultrafine tungsten heavy alloy powders with bater-base solution made from the ammonium metatungstate (AMT), iron(II) chloride tetrahydrate ($FeCl_2{\cdot}4H_2O$), nickel(II) chloride hexahydrate ($NiCl_2{\cdot}6H_2O$) as source materials and the sodium tungstate dihydrate ($NaWO_4{\cdot}2H_2O$) as Cl-reductant. In the preparation of mixtures the amounts of the source components were chosen so as to obtain alloy of 93W-5Ni-2Fe composition(wt.%). The obtained powders were characterized by X-ray diffraction, XRF, field-emission scanning microscope (FESEM), and chemical composition was analyzed by EDX.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.5 no.3
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• pp.269-277
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• 1995

Ultrafine TEX>$Al_2O_3$ powders were prepared from $AlCl_3$ and $Al_2(SO_4)_3$3 by using inductively coupled plasma (lCP) of ultrahigh temperature (above 5000 K) in heat source. The prepared $Al_2O_3$ powders had ${\alpha} - group ({\alpha}, {wdelta} ;and; {\theta})$ phase, a narrow size distribution and around 20 nm in meansize. It could be suggested that gas - solid reaction growth and interparticle sintering occured at the center of ICP tail flame (X = 500 mm) through the results of deposited aggregates - flock, whisker and platy on MgO polycrystal plate. And the formation mechanism of $Al_2O_3$ powders In spray - ICP reactor were described from upper results.

• Journal of Powder Materials
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• v.17 no.2
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• pp.142-147
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• 2010

The ultrafine titanium carbonitride ($TiC_xN_y$) particles below 100 nm in mean size, including various carbon and nitrogen contents (x=0.55~0.9, y=0.1~0.5), were successfully synthesized by new Mg-thermal reduction process. Nanostructured sub-stoichiometric titanium carbide ($TiC_x$) particles were initially produced by the magnesium reduction of gaseous $TiCl_4+x/2C_2Cl_4$ at $890^{\circ}C$ and post heat treatments in vacuum were performed for 2 hrs to remove residual magnesium and magnesium chloride mixed with $TiC_x$. Finally, well C/N-controled $TiC_xN_y$ phases were successfully produced by nitrification heat treatment under normal $N_2$ gas atmosphere at $1150^{\circ}C$ for 2 hrs. The values of purity, mean particle size and oxygen content of produced particles were about 99.3%, 100 nm and 0.2 wt.%, respectively.

• Journal of the Korean Ceramic Society
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• v.27 no.5
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• pp.684-692
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• 1990

Ultrafine magnetite powder for the ferromagnetic fluid was prepared by an addition of alkaline solution to the solution containing Fe2+ and Fe3+ ions at 6$0^{\circ}C$. The optimum condition of the magnetite synthesis was delineated by examining such various physico-chemical properties as Fe2+/Fe+3 ratio in the powder, phase characteristics, MHC and $\sigma$max. A new scheme for the steric stabilization of colloidal dispersion was proposed using the concept of the buffer group action for the increased interfacial density of the stabilizing moieties at colloid particle/dispersion medium interface. The proposed concept was successfully applied to the preparation of the kinetically stable kerosinebased ferrofluid using Tween and Span as dispersants. In the dispersion of magnetite particles in a kerosine, Tween(polyoxyethylene sorbitan oleate) acts as a primary stabilizer which provides an anchor group, whereas Span(sorbitan oleate) can be classified as a secondary stabilizer which adsorbs on the surface of magnetite particle through the action of the buffer group. Dispersion studies using various quantities of Tween and Span supported the concept of the buffer group action for increased dispersion characteristics of the kerosine based ferromagnetic fluid.