• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1016-1018
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• 1995

In this paper, we studied the electrical and the microwave properties of the amorphous $As_{10}Ge_{15}Te_{75}$ thin film. The electrical properties of a-$As_{10}Ge_{15}Te_{75}$ thin film were examined d.c. and a.c. bias with annealing condition. As the result of the electrical properties, we observed the physical characteristics of a-$As_{10}Ge_{15}Te_{75}$ thin film such as the density of defect states, characteristic relaxation time, localized density of states, and localized wave function by using CBH and QMT model. We also examined the microwave conduction properties before and after d.e. switching.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.11a
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• pp.67-70
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• 1995

Amorpous As$\sub$10/Ge$\sub$15/Te$\sub$75/ device shows the memory switching characterisite under d.c. bias. In bulk material, a-As$\sub$10/Ge/sub15/Te$\sub$75/s switching voltage range is above 100 volts. Our purposes in this gaudy are decreasing a switching threshold voltage, finding the properties of d.c., a.c. conduction, and the characterisitics of switching threshold voltage fur a-As$\sub$10/Ge$\sub$15/Te$\sub$75/. As the results, the d.c.and a.c. conductivities increase with temperature. From the data of conductivity, various electrical and physical properties are obtained experimentally. The switching threshold voltages decrease with increasing annealing temperature and time, but increase with increasing film thickness and distance of electrode for d.c. bias.

• Solar Energy
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• v.17 no.3
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• pp.51-57
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• 1997

Cu-doped ZnTe thin films have been grown by hot-wall evaporation. The electrical conductivity of the intrinsic ZnTe film was of p-type and as low as $10^{-6}({\Omega}{\cdot}cm)^{-1}$. As the doped Cu concentration was increased, the electrical conductivity was increased. up to $10^2({\Omega}{\cdot}cm)^{-1}$, but the mobility was decreased a little. The heavily doped sample shows the metal-like electrical resistivity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.813-816
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• 2002

We investigate the junction between CdZnTe and a variety of metals with the aim of determining whether the choice of metal can improve the performance of X-ray image detectors, in particular minimizing the dark current. The samples consist of $5{\mu}m$ thick CdZnTe with top electrodes formed from In, Al, and Au. For each metal, current transients following application of valtages from -10V to 10V are measured for up to 1 hour. We find that dark currents depending on the metal used. The current is controlled by hole injection at the metal-CdZnTe junction and there is consistent trend with the metal's work function possibly and it seems that metal to CdZnTe layer junction is ohmic contact.

• Preventive Nutrition and Food Science
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• v.17 no.2
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• pp.136-140
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• 2012

Trifoliate orange seed extracts (TSEs) were made using either distilled water (TW), ethanol (TE), or n-hexane (TH), to measure total polyphenol contents, DPPH and ABTS radical scavenging activities, and anti-complementary activity. The results showed that the total polyphenol content showed higher value at TE (235.24 ${\mu}g/mL$, p<0.05) than those of TW (132.65 ${\mu}g/mL$) and TH (165.44 ${\mu}g/mL$) at 10 mg/mL and TE exerted the highest DPPH radical scavenging activity (61.77%, p<0.05), which occurred in the following order: TE TW (56.87%)>TH (39.78%). The results of ABTS radical scavenging activity showed that TW (34.26%) and TE (31.81%) showed similar activities, which were higher than TH (12.74%, p<0.05). Anti-complementary activity of TE (61% at 500 ${\mu}g/mL$) showed a higher activity when compared with the positive control (60% at 1,000 ${\mu}g/mL$) polysaccharide-K (PSK), a known immuno-active polysaccharide from Coriolus versicolor. Consequently, among TSEs, TE is a byproduct from trifoliate orange and could be an important source of dietary polyphenolic antioxidant compounds and immunopotentiating activity, including complement activation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.112-113
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• 2006

A stoichiometric mixture for $Cdln_2Te_4$ single crystal was prepared from horizontal electric furnace. The $Cdln_2Te_4$ single crystal was grown in the three-stage vertical electric furnace by using Bridgman method. The quality of the grown crystal has been investigated by the x-ray diffraction and the photoluminescence measurements. The (001) growth plane of oriented $Cdln_2Te_4$ single crystal was confirmed from back-reflection Laue patterns. The carrier density and mobility of $Cdln_2Te_4$ single crystal measured with Hall effect by van der Pauw method are $8.61{\times}10^{16}\;cm^{-3}$ and $242\;cm^2/V{\cdot}s$ at 293 K, respectively. The temperature dependence of the energy band gap of the $Cdln_2Te_4$ single crystal obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)\;=\;1.4750\;eV\;-\;(7.69{\times}\;10^{-3}\;eV)T^2/(T+2147)$.

• Korean Journal of Materials Research
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• v.9 no.5
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• pp.520-527
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• 1999

As a new approache(extrusion-sintering process) to fabricate the thermoelectric materials, it has been at tempted to extrude and sinter the powders simultaneously. It was possible to produce the highly dense <$(Bi,Sb)_2(Te,Se)_3$-based thermoelectrics with sound surface appearances and microstructures by adjusting the process variables. For the p-type materials, the Seeback coefficient was increased with the amount of Te dopants, and the thermoelectric figure of merit appeared to be $2.5\times10^{-3}/K$ at room temperature when doped with 3 at % Te. The n-type specimen doped with 0.16 mol% $SbI_3$ showed the thermoelectric figure of merit of $1.8\times10^{-3}/K$. In both p-type an 우-type materials, the carrier mobility an the thermoelectric figure of merit parallel to the extrusion direction were higher than those perpendicular to it.

• Korean Journal of Materials Research
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• v.10 no.3
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• pp.246-252
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• 2000

Thermoelectric properties of the $Bi_2(Te_{0.85}Se_{0.15})_3$ alloy, prepared by mechanical alloying and hot pressing, were investigated with the variation of the hot-pressing temperature ranging from $300^{\circ}C$ to $550^{\circ}C$. Contrary to the p-type behavior of single crystal, the hot-pressed $Bi_2(Te_{0.85}Se_{0.15})_3$ alloy exhibited n-type conduction without addition of donor dopant. When the $Bi_2(Te_{0.85}Se_{0.15})_3$ powders were annealed in $(50{\%}\;H_2+50{\%}\;Ar)$ atmosphere, the hot-pressed specimens exhibited a positive Seebeck coefficient due to the reduction of the electron concentration by removal of the oxide layer on the powder surface and annealing-out of the excess Te vacancies. Figure-of-merit of the hot-pressed $Bi_2(Te_{0.85}Se_{0.15})_3$ alloy was improved by hot pressing at temperatures above $450^{\circ}C$, and the maximum value of $1.92{\times}10^{-3}/K$ was obtained for the specimen hot-pressed at $550^{\circ}C$.

• Journal of the Korean Applied Science and Technology
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• v.41 no.1
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• pp.58-68
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• 2024

The purpose of this study was to investigate the effects of treadmill exercise treadmill exercise (TE) and environmental enrichment (EE) interventions on cognitive function, muscle function, and the expression of tight junction proteins in an Alzheimer's disease (AD) animal model. To create the AD animal model, aluminum chloride (AlCl₃) was administered for 90 days (40mg/kg/day), while simultaneously exposing the animals to TE (10-12m/min, 40-60min/day) or EE. The results showed that cognitive impairment and muscle dysfunction induced by AlCl₃ administration were alleviated by TE and EE. Furthermore, TE and EE reduced the increased expression of β-amyloid(Aβ), alpha-synuclein, and tumor necrosis factor-α (TNF-α) proteins observed in AD pathology. Additionally, TE and EE significantly increased the expression of decreased adhesive adjacent proteins (Occludin, Claudin-5, and ZO-1) induced by AlCl₃ administration. Lastly, correlation analysis between Aβ protein and tight junction proteins showed negative correlations (Occludin: r=-0.853, p=0.001; Claudin-5: r=-0.352, p=0.915; ZO-1: r=-0.424, p=0.0390). In conclusion, TE or EE interventions are considered effective exercise methods that partially alleviate pathological features of AD, improving cognitive and muscle function.

• Progress in Medical Physics
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• v.24 no.3
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• pp.162-170
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• 2013

Dedicated single-photon emission computed tomography (SPECT) systems based on pixelated semiconductors are being developed for studying small animal models of human disease. To clarify the possibility of using a SPECT system with CdTe for a high resolution low-dose small animal imaging, we compared the quality of reconstructed images from pixelated CdTe detector to those from a small SPECT system with NaI(Tl). The CdTe detector was $44.8{\times}44.8$ mm and the pixels were $0.35{\times}0.35{\times}5$ mm. The intrinsic resolution of the detector was 0.35 mm, which is equal to the pixel size. GATE simulations were performed to assess the image quality of both SPECT systems. The spatial resolutions and sensitivities for both systems were evaluated using a 10 MBq $^{99m}Tc$ point source. The quantitative comparison with different injected dose was performed using a voxelized MOBY phantom, and the absorbed doses for each organ were evaluated. The spatial resolution of the SPECT with NaI(Tl) was about 1.54 mm FWHM, while that of the SPECT with a CdTe detector was about 1.32 mm FWHM at 30 mm. The sensitivity of NaI(Tl) based SPECT was 83 cps/MBq, while that of the CdTe detector based SPECT was 116 cps/MBq at 30 mm. The image statistics were evaluated by calculating the CNR of the image from both systems. When the injected activity for the striatum in the mouse brain was 160 Bq/voxel, the CNR of CdTe based SPECT was 2.30 while that of NaI(Tl) based SPECT was 1.85. The CNR of SPECT with CdTe was overall higher than that of the NaI(Tl) based SPECT. In addition, the absorbed dose was higher from SPECT with CdTe than those from NaI(Tl) based SPECT to acquire the same quantitative values. Our simulation results indicated that the SPECT with CdTe detector showed overall high performance compared to the SPECT with NaI(Tl). Even though the validation study is needed, the SPECT system with CdTe detector appeared to be feasible for high resolution low-dose small animal imaging.