• Korean Journal of Crystallography
• /
• v.15 no.1
• /
• pp.24-28
• /
• 2004

The structure of $C_{12}H_{15}N_3O_3$ has been determined by X-ray diffraction methods. The crystal system is monoclinic, space group $P2_1/c$, unit cell constants, a = 12.9955(9) ${\AA}$, b = 7.7137(5) ${\AA}$, c = 13.4699(11) ${\AA}$, ${\beta}$ = 107.86(1)$^{\circ}$, V = 1285.2(1) ${\AA}^3$, T = 296 K, Z = 4, $D_c$ = 1.350 $Mgm^{-3}$. The intensity data were collected on an Enraf-Nonius CAD-4 Diffractometer with graphite monochromated Mo $K{\alpha}$ radiation (${\lambda}$ = 1.71073 ${\AA}$). The molecular structure was solved by direct methods and refined by full-matrix least squares to a final R = 4.19% for 1644 unique observed $F_0\;>\;4{\sigma}(F_0)$ reflections 193 parameters.

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2005.06a
• /
• pp.284-289
• /
• 2005

According to the nuclear safety regulation policy including the administration of radionuclides in low level radwastes, the evaporator bottoms were mixed with cement to form a stable solidification for identifying the recovery possibility of the C-14. The chemical oxidation method was applied for the extraction of C-14 from the cement waste form. The emitting beta ray of the C-14 extracted from the radwastes was measured with the liquid scintillation counter and calculated by using the quenching correction curves. Only the beta emitting radioactive nuclides of the C-14 in the radwastes was showed the radioactivities with the range of $2.7E+00\;{\sim}\;3.07E+02$ Bq/g.

• Korean Journal of Crystallography
• /
• v.15 no.2
• /
• pp.93-98
• /
• 2004

The structure of C_{28}H_{41}N_4O_4Br\;{\cdot}\;2H_2O$ has been determined by X-ray deffraction methods. The crystal system is triclinic, space group Pl, unit cell constants, a=9.000(1) $\AA$, b=9.312(3) $\AA$, c=9.344(2) $\AA$, $\alpha=89.37(20)^{\circ},\;\beta=68.81(3)^{\circ},\;\gamma=84.70(4)^{\circ},\;V=726.7(8){\AA},\;T=298K,\;Z=1,\;D_c=1.402Mgm^{-3}$. The intensity data were collected on an Enraf-Nonius CAD4 Diffractometer with graphite monochromated $MoK\alpha$ radiation $(\lambda=0.71073\;{\AA}$. The molecular structure was solved by direct methods and refined by full-matrix least squares to a final $R=5.95\%$ for 2521 unique observed $F_0>4\sigma(F_0)$reflections and 370 parameters.

• Korean Journal of Materials Research
• /
• v.28 no.9
• /
• pp.511-515
• /
• 2018

W-10 wt% Ti alloys that have a homogeneous microstructure are prepared by thermal decomposition of $WO_3-TiH_2$ powder mixtures and spark plasma sintering. The reduction and dehydrogenation behavior of $WO_3$ and $TiH_2$ are analyzed by temperature programmed reduction and a thermogravimetric method, respectively. The X-ray diffraction analysis of the powder mixture, heat-treated in an argon atmosphere, shows W- oxides and $TiO_2$ peaks. Conversely, the powder mixtures heated in a hydrogen atmosphere are composed of W, $WO_2$ and $TiO_2$ phases at $600^{\circ}C$ and W and W-rich ${\beta}$ phases at $800^{\circ}C$. The densified specimen by spark plasma sintering at $1500^{\circ}C$ in a vacuum using hydrogen-reduced $WO_3-TiH_2$ powder mixtures shows a Vickers hardness value of 4.6 GPa and a homogeneous microstructure with pure W, ${\beta}$ and Ti phases. The phase evolution dependent on the atmosphere and temperature is explained by the thermal decomposition and reaction behavior of $WO_3$ and $TiH_2$.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.22 no.2
• /
• pp.99-104
• /
• 2012

The co-precipitation technique has been applied to synthesize biphasic calcium phosphate (BCP). $Ca(NO_3)_2{\cdot}4H_2O$ and $(NH_4)_2HPO_4$ as the starting materials was used. X-ray diffraction (XRD) and Fourier transformed infrared (FT-IR) spectroscopy were used to characterize the structure of as-synthesized and calcined BCP powders. After immersion in Hanks' Balanced Salt Solution (HBSS), for 1 week a precipitation started to be formed with individual small granules on the specimen surface. An MTT assay indicated that BCP powders have no cytotoxic effects on MG-63 cells, and that they have good biocompatibility.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.34 no.3
• /
• pp.341-346
• /
• 2010

The effect of specimen geometry on the bending and tensile strengths of dissimilar joints ($\beta-Si_3N_4/S45C$) with copper interlayers was evaluated. The average bending strength of specimens with circular cross sections was higher than that of specimens with rectangular cross sections. The crack initiation stress ($\sigma_i$) was successfully determined by the acoustic emission (AE) method and was approximately 60~80% of the bending strength. The residual stresses near the interfaces on the ceramic side were measured by X-ray diffraction before conducting the bending test. The bending strength and the crack initiation stress decreased with an increase in the residual stresses. The effect of the bending strain component was evaluated by the tensile testing; the tensile strength decreased with an increase in the bending strain component and was approximately 80% of the bending strength.

• Applied Chemistry for Engineering
• /
• v.23 no.2
• /
• pp.138-142
• /
• 2012

The ${\epsilon}$ type copper phthalocyanine (${\epsilon}$-CuPc), called as a pigment blue 15 : 6, is a significant material to produce a blue pixel in LCD (Liquid Crystal Display) panel. In this study, ${\epsilon}$-CuPc sample was synthesized at various reaction conditions by applying the seed method using ${\epsilon}$-CuPc nanoparticles as a seed. Adequate synthetic conditions of the samples were selected by analyzing and comparing crystalline structure, crystalline purity, microstructure, and synthetic yield of the samples with ${\alpha}$ and ${\beta}$ crystalline CuPc samples. The chemical and crystalline structure of the samples were tested using FT-IR spectrometer and X-ray diffractometry, respectively. The shape of the particle was examined using field emission scanning electiron microscope while the thermal property was tested utilizing thermogravimetric analysis.

• Korean Journal of Materials Research
• /
• v.11 no.8
• /
• pp.647-654
• /
• 2001

Effects of final annealing temperature on the precipitate and oxidation were investigated for the Zr-lNb and Zr-lNb-lSn-0.3Fe alloys. The microstructure and oxidation of both alloys were evaluated for the optimization of final annealing process of these alloys in the annealing temperature regime of 450 to $800^{\circ}C$. The corrosion test was performed under steam at $400^{\circ}C$ for 270 days in a static autoclave. The oxide formed was identified by low angle X-ray diffraction method. The $\beta$-Zr was observed at annealing temperature above $600^{\circ}C$. Above $600^{\circ}C$, the precipitate area volume fraction of Zr-lNb and Zr-1Nb-lSn-0.3Fe alloys appeared to be increased with increasing the final annealing temperature. The corrosion resistance of Zr-lNb was higher than that of Zr- lNb-lSn-0.3Fe alloy. The corrosion rate of both alloys were accelerated due to the formation and growth of $\beta$-Zr with increasing the annealing temperature.

• Journal of the Korean Magnetics Society
• /
• v.16 no.4
• /
• pp.221-227
• /
• 2006

We have synthesized uniform nanometer sized magnetite particles using chemical coprecipitation technique through a sonochemical method with surfactant such as oleic acid. Magnetite phase nanoparticles could be observed from X-ray diffraction. Magnetite nanoparticles is surface phase morphology and biopolymer-microspheres for Application Medical. Magnetite nanoparticles coated biopolymer. Atomic Force Microscope (AFM) was used to image the coated nanoparticles. Magnetic colloid suspensions containing particles with sodium oleate, chitosan and $\beta$-glucan have been prepared. The morphology of the magnetic biopolymer microsphere particles were characterized using optical microscope. Magnetic hysteresis measurement were performed using a superconducting quantum interference device (SQUID) magnetometer at room temperature to investigate the magnetic properties of the biopolymer microspheres and magnetite coated biopolymer including magnetite nanoparticles. Magnetic Resonance (MR) imaging was used to investigate biopolymer coated nanoparticles and biopolymer microspheres.

• Journal of the Korean institute of surface engineering
• /
• v.41 no.5
• /
• pp.181-188
• /
• 2008

A.C. impedance properties of HA/Ti compound layer coated Ti-30Ta-($3{\sim}15$)Nb alloys have been studied by electrochemical method. Ti-30Ta binary alloys contained 3, 7, 10 and 15 wt% Nb were manufactured by the vacuum furnace system. And then specimen was homogenized at $1000^{\circ}C$ for 24 hrs. The sample was cut and polished for corrosion test and coating. It was coated with HA/Ti compound layer by magnetron sputter. The non-coated and coated morphology of Ti alloy were analyzed by X-ray diffractometer (XRD), energy X-ray dispersive spectroscopy (EDX) and filed emission scanning electron microscope (FE-SEM). The corrosion behaviors were investigated using A.C. impedance test (PARSTAT 2273, USA) in 0.9% NaCl solution at $36.5{\pm}1^{\circ}C$. Ti-30Ta-($3{\sim}15\;wt%$)Nb alloys showed the ${\alpha}+{\beta}$ phase, and $\beta$ phase peak was predominantly appeared in the case of increasingly Nb contents. The microstructures of Ti alloy were transformed from needle-like structure to equiaxed structure as Nb content increased. From the analysis of coating surface, HA/Ti composite surface uniformed coating layer with 750 nm thickness. The growth directions of film were (211), (112), (300) and (202) for HA/Ti composite coating on the surface after heat treatment at $550^{\circ}C$, whereas, the growth direction of film was (110) for Ti coating. The polarization resistance ($R_p$) of HA/Ti composite coated Ti-alloys were higher than those of the Ti and HA coated samples in 0.9% NaCl solution at $36.5{\pm}1^{\circ}C$. Especially, corrosion resistance of Ti-Ta-Nb system increased as Nb content increased.