• Applied Microscopy
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• v.36 no.spc1
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• pp.1-7
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• 2006

The three-dimensional structure of an inorganic crystal, $SmZn_{0.67}Sb_2$ (space group $P4/nmm,\;a=4.30(3){\AA}\;and\;c= 10.27(1){\AA}$), was refined by electron crystallography utilizing high voltage electron microscopy (HVEM). Effects of instrumental resolution, image quality, beam damage and specimen tilting on the structure refinement have been evaluated. The instrumental resolution and image quality were the most important factors on the final results in the structure refinement, while the beam damage and specimen tilting effects could be experimentally minimized or controlled. The average phase errors $({\Phi}_{res})$ for the [001], [100] and [110] HVEM images of $SmZn_{0.67}Sb_2$ were $10.1^{\circ},\;9.6^{\circ}\;and\;6.8^{\circ}$, respectively. The atomic coordinates of $SmZn_{0.67}Sb_2$ were consistent within $0.0013{\AA}{\sim}0.0088{\AA}$, compared to the X-ray crystallography data for the same sample.

• Korean Journal of Optics and Photonics
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• v.12 no.5
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• pp.394-400
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• 2001

We studied thermal diffusion properties diffusion properties of multi-layered Ge-Sb-Te alloy thin films for optical recording media by solving the thermal equation. Based on the numerical analysis of optical energy distribution and absorption inside multi-layered films including temperature gradient and heat transfer simultaneously, we proposed the optimum parameters of the input laser power and the multi-layer structure as follow. i) Input laser power is 18 mW, ii) laser exposure time is 60 ns, iii) the thicknesses of the lower and the upper ZnS-SiO$_2$are 140 nm and 20~30 nm respectively, and iv) thickness of Ge-Sb-Te recording film is 20 nm.

• Journal of the Korean Ceramic Society
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• v.28 no.2
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• pp.160-166
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• 1991

Microstructure and phase changes during the sintering of ZnO varistors were studied in ZnO-Bi2O3-CoO-Sb2O3 and ZnO-Bi2O3-CoO-Sb2O3-Cr2O3 systems using acanning electron microscopy (SEM) with an energy dispersive X-ray analysis (EDAX), X-ray diffraction (XRD) and differential thermal analysis (DTA). The spinel phase and the Bi2O3 phase were formed by the decomposition of the pyrochlore phase during heating. The spinel particles (2-4$\mu\textrm{m}$), which were formed both along ther grain boundaries and within the ZnO grain, were always found near the pyrochlore phase. Intergranular phases (Bi2O3 and pyrochlore) were precipitated from the liquid phase during cooling. The Bi2O3 phases were located at the triple (or multiple) point of the ZnO grains. Cr2O3 played a role in decreasing the formation temperature of the spinel phase and Bi2O3 phase during sintering, and inhibited the grain growth.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.11
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• pp.854-858
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• 2010

In this study, we have investigated the effects of Cr dopant on the sintering and electrical properties of ZnO-$Sb_2O_3$ (ZS) ceramics for varistor application. Spinel phases including $\alpha-$ and $\beta$-type was formed at ZS system and $\alpha$-spinel was stabilized by Cr doping in ZS system. Densification of ZS and ZSCr system was retarded to $1000^{\circ}C$ by the formation of spinel at $800^{\circ}C$. The morphology and its distribution of spinel phases in ZS system was homogeneous but disturbed by Cr doping. In ZSCr the densification of ZnO compared with ZS system was more retarded by low concentration of Zn interstitial defects induced by Cr doping in addition to the effect of spinel phase formation. The defects in each system were identified as attractive coulombic center (ZS: 0.13 eV, ZSCr: 0.12 eV) and singly charged oxygen vacancy $V_0^{\cdot}$ (ZSCr: 0.33 eV). In all ZS and ZSCr system have week varistor behavior by the formation of double Schottky barrier at grain boundary but its stability of barrier was very sensitive to sintering temperature.

• Proceedings of the KIEE Conference
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• 1987.07a
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• pp.565-568
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• 1987

In order to determine the standard composition of ZnO varistor with higher nonlinearity, various contents of $MnO_2$, $Co_2O_3$ were added to ZnO-1.0m/o $Bi_2O_3$ system. Also, samples that contained small amount of Sb, Si-oxides in standard composition determined before were fabricated. As a result, the standard composition of higher nonlinearity-oriented ZnO varistor was shown as ZnO-1.0 m/o $Bi_2O_3$-1.0m/o $MnO_2$-1.0m/o $Co_2O_3$ and $Sb_2O_3$ largely enhanced nonlinear exponent and nonlinear resistance, hut SiO largely enhanced nonlinear exponent only.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.5
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• pp.690-699
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• 2017

Objective: This study aimed to examine the effect of sodium butyrate (SB) on growth performance, immune status, organs weights, and microarchitecture of lymphoid organs and small intestine. Methods: A total of 120, 1-d-old broiler chicks were distributed into the following four treatment groups: corn-soy based basal diet (BD) without supplement (control), or the same BD supplemented with 0.1 g/kg zinc bacitracin (ZnB), 0.5 g/kg SB (SB-0.5), or 1.0 g/kg SB (SB-1), respectively. Six birds/group were killed on d-21 and d-35, and samples were collected. Results: Cell-mediated immune response at 48 h post-Phytohemagglutinin-P injection, and antibody titer against Newcastle disease vaccine and sheep red blood cells on d-35 was noted higher (p<0.05) in SB-1 compared to ZnB and control. Lower (p<0.05) feed conversion ratio (FCR) was attained by the supplemented groups. Thymus and spleen weighed more (p<0.05) in SB-1, and bursa registered more (p<0.05) weight in both SB groups compared to control. On d-21, areas of thymus medulla and spleen germinal centers were noted higher (p<0.05) in SB-1 group. The villus height and villus surface area increased (p<0.05) in duodenum and jejunum in both SB groups on d-21, and in SB-1 on d-35, respectively compared to ZnB and control. On d-21, number of goblet cells containing mucins of acidic nature increased (p<0.05) in all the segments of small intestines in SB-1 group compared to control, and on d-35 in ileum compared to other groups. Conclusion: In conclusion, SB improved growth performance and immunity as well as modulated morphology of lymphoid organs and gut mucosa in broiler chickens.

• Applied Microscopy
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• v.34 no.4
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• pp.255-264
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• 2004

The three-dimensional (3D) structure of an inorganic crystal, $SmZn_{0.67}Sb_2$ (space group P4/nmm, $a=4.26{\AA}\;and\;c=10.37{\AA}$) was solved by electron crystallography. High resolution electron microscopy (HREM) images from 3 different major zone axes and selected-area electron diffraction patterns from 16 different zone axes were combined to obtain a 3D information. A crystallographic image processing (CIP) of HREM images was used for more accurate determination of the crystal structure. As a result of this electron crystallography, average phase errors (${\Phi}_{res}$) of [001], [100] and [110] HREM images are $17.0^{\circ},\;8.3^{\circ}\;and\;21.9^{\circ}$, respectively. Xray crystallography of $SmZn_{0.67}Sb_2$ has attempted to compare accuracy of the structure determination by electron crystallography, which resulted in the cell parameters of $a=4.2976(6){\AA}\;and\;c=10.287(2){\AA}$, and the R-factor ($R_{sym}$) of 4.16%.

• Applied Chemistry for Engineering
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• v.10 no.6
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• pp.917-922
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• 1999

The transesterification of dimethyl terephthalate(DMT) with ethylene glycol(EG) was kinetically investigated in the temperature range from 190 to $240^{\circ}C$ with and without a zinc acetate(Zn) as a catalyst. The degree of reaction was calculated by the measurement of the quantity of methanol which distilled from the reaction vessel. This distillation made corrections of reactant and catalyst concentrations necessary. The effects of catalyst concentration, molar ratio of DMT and EG, types of metal compounds, and temperature on kinetics were studied. The catalytic activity of various metal compounds was excellent, in order of Ti, Zn, Sn, and Sb. Also the order of activation energy was Zn>Ti>Sn>Sb.

• Economic and Environmental Geology
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• v.28 no.2
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• pp.147-154
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• 1995

Coal fly ashes collected from the Samcheonpo and the Seocheon Power Plants were analyzed for major and minor components and heavy metals such as As, Cd, Co, Cr, Cu, Ga, Hg, Mo, Ni, Pb, Sb, V and Zn in order to suggest basic data to apply coal fly ash as fertilizer or soil ameliorator. The specific gravity of the samples was less than 2.0, and amounts of organic matter range from 5.0% to 12.3%. The identified minerals by XRD were mainly quartz, mullite and pyrite in anthracite coal, and mainly quartz and mullite in bituminous coal. Generally, the contents of heavy metal elements analyzed were lower less than those of soil, though higher in some samples. Element couples of some elements( e.g., As-Mo, Zn ; Mo-As, Sb, V, Zn ; Sb-Zn ) show positive correlations with each other, but the high correlations of toxic elements such as As, Pb, Cd and Hg indicate to give attention to apply coal fly ash as fertilizer or soil ameliorator.

• Korean Journal of Materials Research
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• v.15 no.7
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• pp.435-438
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• 2005

Single phase $Zn_4Sb_3$ with $98.5\%$ of theoretical density was successfully produced by direct hot pressing of elemental powders containing $1.2 at\%$ excess Zn for compensating the evaporation during the process. Temperature dependences of thermoelectric properties were investigated from 4 K to 300 K. Seebeck coefficient, electrical conductivity, thermal conductivity as well as thermoelectric figure of merit showed the discontinuity in variation at 242K, indicating the $\alpha-\beta$, phase transformation. Interestingly, it was found that lattice thermal conductivity by phonons is dominant in total thermal conductivity of $\alpha-\beta$. Therefore, it is expected that thermoelectric properties can be improved by reduction of lattice thermal conductivity inducing lattice scattering centers by doping and solid solution.