• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.7 no.2
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• pp.167-177
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• 1996

The cutoff frequencies of a double ridged rectangular waveguide are calculated by applying the modal analysis to its cross-section. And the characteristic impedance of its $TE_{10}$ mode is evaluated in a frequency range of 6 to 18 GHz. When both ends of a linearly tapered rectangular wa- veguide consists of single and double ridged rectangular cross-sections, the equivalent nonuniform transmission line of its $TE_{10}$ mode is solved numerically. It is shown that the input impedance at its single ridged terminal becomes nearly constant in the wide bandwidth.

• Journal of Korea Foundry Society
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• v.10 no.4
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• pp.324-331
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• 1990

The single crystal of CdTe was grown by modified 6 zone Bridgman method under the conditions of excess Te and excess Cd. To prevent the constitutional supercooling, the crystal growth was done under the temperature gradient of $17^{\circ}C/cm$ in front of the solid /liquid interface and the growth rate was 3mm/hr. The grain morphologies and the growth mechanism were investigated in excess Te and excess Cd conditions. The grain size of excess Te crystal was increased with an increase of the distance from the tip but, in the case of excess Cd crystal, single crystal was not obtained because of the cavities due to the excess Cd vapors so that the grain size was not increased with an increase of the distance from the tip. In addition, the growth of single crystal of CdTe was done with repeated necking ampoule. It was found that the necking had no effects on the grain selection because the cavities trapped in the necking portion acted as heterogeneous nucleation sites.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.9
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• pp.459-463
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• 2004

In this study, the (l-x)$TiTe_3O_{8}$-x$MgTiO_3$ ceramics were investigated to obtain the improved dielectric properties of a high temperature stability and a sintering temperature of less than $900^{\circ}C$ which was necessary for the LTCC. According to the X-ray diffraction patterns of the (l-x)$TiTe_3O_{8}$-x$MgTiO_3$(x=0∼1) ceramics, the columbite structure of $TiTe_3O_{8}$ and ilmenite structure of $MgTiO_3$ were coexisted. Increasing the $MgTiO_3$ mole ratio(x), the density and dielectric constant were decreased and temperature coefficient of resonant frequency was moved to the negative direction and the quality factor was increased. In the case of the 0.6$TiTe_3O_{8}$-0.4$MgTiO_3$ ceramics sintered at $830^{\circ}C$ for 3hr., the microwave dielectric properties were $\varepsilon_{\gamma}$=29.3, Q${\times}$$f_{\gamma}$=39.600GHz and $\tau$$_{f}$=+9.3ppm/$^{\circ}C$.

• Electrical & Electronic Materials
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• v.10 no.1
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• pp.39-44
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• 1997

Bulk type radiation detector of Au/Cd$_{1-x}$ Zn$_{x}$Te(x=20%)/Au structure using Cd$_{1-x}$ Zn$_{x}$Te(x=20%) wafer(3x4xl mm$^{3}$) grown by high pressure Bridgman method has been developed. We etched wafer surfaces with 2% Br-methanol solution and coated gold thin film on the surfaces by electroless deposition method for 5 min. in 49/o HAuCI$_{3}$ 4H20 solution. Initial etch rates of Cd, Zn and Te were 46%, 12% and 42% respectively. After etched, the surface of wafer was slightly revealed to Te rich condition. The leakage current was increased with etch time, but it didn't exceed 3nA at 50volt. The thickness of Au film was about 100nm by Rutherford Backscattering Spectroscopy(RBS). The resolution were 6.7% for 22.1 keV photon from 109 $^{109}$ Cd and 8.2% for 59.5 keV photon from $^{241}$ Am. The radiation detector such as Au/Cd$_{1-x}$ Zn$_{x}$Te(x=20%)/Au structure was more effective to monitor the low energy gamma radiation.iation.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.4 no.4
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• pp.388-394
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• 1994

A Hg(0.79)Cd(0.21)Te single crystal has been grown by the Traveling Heater Method(THM). Its zinc blend cubic structure is identified from the X-ray diffraction patterns and its lattice constant is determined to be $6.464 {\AA}$ using the least-square method of Cohen. From the values of the lattice constant, the composition x is determined to be 0.21. The electron density is calculated from the relative intensities of the scattered X-ray and compared with the theoretically calculated values. From the electron density distribution, it is shown that the crystal binding of Hg(1-x)Cd(x)Te(MCT) is mainly covalent and has tetrahedron bonds between adjacent atoms.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.376-376
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• 2010

The single crystals of p-$CdIn_2Te_4$ were grown by the Bridgman method without the seed crystal. From photocurrent measurements, it was found that three peaks, A, B, and C, correspond to the intrinsic transition from the valence band states of $\Gamma_7$(A), $\Gamma_6$(B), and $\Gamma_7$(C) to the conduction band state of $\Gamma_6$, respectively. The crystal field splitting and the spin orbit splitting were found to be 0.2360 and 0.1119 eV, respectively, from the photocurrent spectroscopy. The temperature dependence of the $CdIn_2Te_4$ band gap energy was given by the equation of $E_g(T)=E_g(0)-(9.43{\times}10^{-3})T^2/(2676+T)$. $E_g$(0) was estimated to be 1.4750, 1.7110, and 1.8229 eV at the valence band states of A, B, and C, respectively. The band gap energy of p-$CdIn_2Te_4$ at room temperature was determined to be 1.2023 eV.

• Food Science of Animal Resources
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• v.37 no.6
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• pp.889-897
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• 2017

In this study, a nanoemulsion formulation for encapsulating turmeric extract was developed and its physicochemical characteristics including particle diameter, zeta potential, polydispersity index, and stability were determined. The turmeric nanoemulsion (TE-NE) droplets exhibited small diameter (165 nm), low PDI (0.17), and high zeta potential (-31.80 mV), all desirable characteristics in nanoemulsions, as well as stability in a wide range of pH. The TE-NE was spray-dried as a means to allow its incorporation into food products and reduce potential transport and storage costs. The resulting powder exhibited a pale yellowish appearance and had a curcuminoids content of 0.39 mg/g. The spray-dried TE-NE powder was incorporated into minced pork to make canned ham, and the sensory characteristics of the ham were evaluated. As a result, the canned ham incorporating TE-NE powder received the same overall acceptability score as the control, and only exhibited slight yellowing. By contrast, ham incorporating turmeric extract exhibited substantial yellowing, and its appearance was considered less acceptable by the panelists. Therefore, the TE-NE formulation could be incorporated into canned ham and other meat products without substantially affecting their sensory qualities.

• Journal of Powder Materials
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• v.17 no.6
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• pp.494-498
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• 2010

The p-type thermoelectric compounds of $Bi_2Te_3$ based doped with 3wt% Te were fabricated by a combination of rapid solidification and spark plasma sintering (SPS) process. The effect of holding time during spark plasma sintering (SPS) on the microstructure and thermoelectric properties were investigated using scanning electron microscope (SEM), X-ray diffraction (XRD) and thermoelectric properties. The powders as solidified consisted of homogeneous thermoelectric phases. The thermoelectric figure of merit measured to be maximum ($3.41{\times}10^{-3}/K$) at the SPS temperature of $430^{\circ}C$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.6
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• pp.448-453
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• 2019

This work reports the electrical characteristics of and temperature distribution in chalcogenide phase change memory (PCM) devices that have a self-aligned structure. GST (Ge-Sb-Te) chalcogenide alloy films were formed in a self-aligned manner by interdiffusion between sputter-deposited Ge and $Sb_2Te_3$ films during thermal annealing. A transmission electron microscopy-energy dispersive X-ray spectroscopy (TEM-EDS) analysis demonstrated that the local composition of the GST alloy differed significantly and that a $Ge_2Sb_2Te_5$ intermediate layer was formed near the $Ge/Sb_2Te_3$ interface. The programming current and threshold switching voltage of the PCM device were much smaller than those of a control device; this implies that a phase transition occurred only in the $Ge_2Sb_2Te_5$ intermediate layer and not in the entire thickness of the GST alloy. It was confirmed by computer simulation, that the localized phase transition and heat loss suppression of the GST alloy promoted a temperature rise in the PCM device.

• Proceedings of the Korean Vacuum Society Conference
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• 1994.02a
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• pp.43-43
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• 1994

We studied chemical reactio of Eu metal on the in situ cleaved CdTe(110) surface by pphotoemission sppectroscoppy using synchrotron radiation. The chamber was maintained with base ppressure $\leq$2${\times}$10-10 mb during the expperiment. The expperiment was carried out in pphoton Factory in Jappan. Core level pphotoemission sppectroscoppy was carried out with Al K${\alpha}$ Line. The CdTe simiconductor was determined to be pp-typpe with low dopping concentration from Hall measurement. We found that there are two reacted pphases of Te with Eu (related to divalent Eu and trivalent Eu, resppectively) from least square fitting of Te 4d sppectra, but three is no indication of Cd reaction. Trivalent Eu exists after roughly one monolayer depposition (600 sec. depposition time is considered as one monolayer), which is also observed at Eu 3d core level sppectra. Overlayer Eu is metallized after roughly 2 monolayers depposition, as can be deduced from the fact that metallic edge near Fermi level begins to appear. The intensity of core-level of Te decreases expponentially at the initial stage (near one monolayer) and after one monolayer depposition it decreases more slowly due to Te out-diffusion. We categorized the growth mode of Eu on CdTe as S-K growth mode (cluster formation after one monolayer deppisition) from the relative intensity pplot of Te 4d normalized to the cleaved surface. At cleaved surface band bending is already established due to surface defects. At first 100 sec. depposition time the shift toward lower binding side by 0.6 eV is found at all core level sppectra of all elements in semiconductor. This shift is considered as the re-adjustment of surface Fermi level to the pposition induced by Eu metal (0.2 eV above the valence band maximum).