• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.8
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• pp.474-478
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• 2017

We report on thin-film transistors based on $TiO_x$ pre-annealed by femtosecond laser pulses. A 30-nm thick $TiO_x$ active channel layer was initially deposited by an ALD system. The $TiO_x$ semiconducting films were annealed by irradiation with a femtosecond laser (power: $3W/cm^2$) for 5, 25, and 50s. Atomic force microscopy images revealed that the surface of a $TiO_x$ film without femtosecond laser pre-annealing was relatively rough, while after annealing with femtosecond laser pulses, the surface of the $TiO_x$ films became smooth. With increasing radiation time, the surrounding gas atmosphere could have a larger impact on the $TiO_x$ surface; meanwhile, the thin-film roughness decreased. Thin-film transistors with $TiO_x$ active channels pre-annealed at 50s exhibited good transfer characteristics and an on-to-off current ratio of ${\sim}10^3$.

• Journal of radiological science and technology
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• v.16 no.2
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• pp.45-50
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• 1993

In this paper, the PAE of tube voltage of 93 diagnostic X-ray units those are using at the 19 general hospitals and 9 local clinics in the area of Sungnam, Inchun, and Seoul have been surveyed. The results are summarized as following. 1. PAE of tube Voltage 70, 100KV at the 56 (60%) X-ray units were ${\pm}7%$ below, at the 8 units (9%), were ${\pm}7%$ above, and those 29 X-ray units (31%) were ${\pm}7%$ below or above with the 70, 100KV tube Voltage in a unit. 2. PAE ${\pm}7%$ below were 68 X-ray units, at the low tube voltage (70KV), and 76 X-ray units at the high tube Voltage (100KV). 3. For six year-use abofe, used X-ray units were PAE ${\pm}7%$ above, and so, the longer used years the more X-ray units became declined in those performance. 4. PAE of tube Voltage were better efficiency at the large capacity 30 X-ray units than small capacity 10. 5. PAE ${\pm}7%$ abovein were only 8 units among 84 diagnostic X-ray units in the general hospitals.

• Bulletin of the Korean Chemical Society
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• v.15 no.8
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• pp.636-640
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• 1994

The nonstoichiometric perovskite solid solutions of the $Nd_{1-x}Sr_xFeO_{3-y}$ system for the compositions of x=0.00, 0.25, 0.50, 0.75, and 1.00 have been prepared at $1150^{\circ}C$ in the air pressure. The compound of x=0.00, NdFe$O_{3.0}$, contains only $Fe^{3+}$ ion in octahedral site and the others involves the mixed valence state between $Fe^{3+}$ and $Fe^{4+}$ ions. The mole ratio of $Fe^{4+}$ ion or the ${\tau}$-value increases steadily with the x-value and then is maximized at the compositionof x= 1.00. The nonstoichiometric chemical formulas of the system are formulated from the x, ${\tau}$ and y values. From the Mossbauer spectroscopy, the isomer shift of $Fe^{3+}$ ion decreases with the increasing x-value, which is induced by the electron transfer between the$Fe^{3+}$ and $Fe^{4+}$ ions. The transfer is made possible by the indirect interaction between $Fe^{3+}$ and$Fe^{4+}$ ions via the oxygen ion. The eg electrons of the$Fe^{3+}$ ions are delocalized over all the Fe ions. Due to the electron transfer, the activation energy of electrical conductivity is decrease with the increasing amount of $Fe^{4+}$ ion.

• Journal of the Semiconductor & Display Technology
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• v.8 no.3
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• pp.13-17
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• 2009

we have studied characterization of microbolometer based on the co-sputtered silicon-antimony ($Si_{1-x}Sb_x$) thin film for infrared microbolometer. We have investigated the resistivity and the temperature coefficient of resistance (TCR) with annealing. We deposited the films using co-sputtering method at $200^{\circ}C$ in the Ar environment. The Sb concentration has been adjusted by applying variable DC power from Sb targets. TCR of deposited $Si_{1-x}Sb_x$ films have been measured the range of -2.3~-2.8%/K. The resistivity of the film is low but TCR is higher than the other bolometer materials. Resistivity of the films has not been affected hugely according to the low annealing temperature however the resistivity has been dramatically decreased over $250^{\circ}C$. It is caused of a phase change due to the rearrangement of Si and Sb atoms during crystallization process of the films.

• Journal of the Korean Vacuum Society
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• v.9 no.4
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• pp.346-352
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• 2000

We investigated the oxidation behavior of poly $Si_{1-x}Ge_x$ films (X=0.15, 0.42) at $700^{\circ}C$ in wet oxidation ambients and analyzed the oxide by XPS, RBS, and cross-sectional TEM. In the case of poly $Si_{0.85}Ge_{0.15}$ films, $SiO_2$ was formed on the poly $Si_{1-x}Ge_x$ films and Ge was rejected from growing oxide, subsequently leading to the increase of Ge content. In the case of poly $Si_{0.58}Ge_{0.42}$ films, we found that $SiO_2-GeO_2$ were formed on the poly $Si_{1-x}Ge_x$ films due to high Ge content. Finally, we proposed the oxidation model of poly $Si_{1-x}Ge_x$ films.

• Bulletin of the Korean Mathematical Society
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• v.39 no.2
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• pp.269-276
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• 2002

Let E be a real Banach space. Let T : E longrightarrow E be a map with F(T) : = { x $\in$ E : Tx = x} $\neq$ 0 and satisfying the accretive-type condition $\lambda\$\mid$x-Tx\$\mid$^2$, for all $x\inE,\;x^*\inf(T)\;and\;\lambda >0$. We prove some necessary and sufficient conditions for the convergence of the Mann iterative sequence to a fixed point of T.

• Korean Journal of Mathematics
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• v.17 no.3
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• pp.315-330
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• 2009

Using the fixed point method, we prove the generalized Hyers-Ulam stability of the following cubic-quadratic functional equation $$(0.1)\;\frac{1}{2}(f(2x+y)+f(2x-y)-f(-2x-y)-f(y- 2x))\\{\hspace{35}}=2f(x+y)+2f(x-y)+4f(x)-8f(-x)-2f(y)-2f(-y)$$ in fuzzy Banach spaces.

• Journal of the Korean Magnetics Society
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• v.19 no.4
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• pp.121-125
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• 2009

Amorphous $Ge_1$_$_xMn_x$ semiconductor thin films grown by low temperature vapor deposition were annealed at various temperatures from 400 to $700^{\circ}C$ for 3 minutes in high vaccum chamber. The electrical and magnetotransport properties of as-grown and annealed samples have been studied. X-ray diffraction patterns analysis revealed that the samples still maintain amorphous state after annealling at $500^{\circ}C$ for 3 minutes and they were crystallized when annealing temperature increase to $600^{\circ}C$. Temperature dependence of resistivity measurement implied that as-grown and annealed $Ge_1$_$_xMn_x$ films have semiconductor characteristics, the increase of resistivity with annealling temperature was obseved. The $700^{\circ}C$-annealed sample exhibited negative magnetoresistance (MR) at low temperatures and the MR ratio was ${\sim}$8.5% at 10 K. The asymmetry was present in all MR curves. The anomalous Hall Effect was also observed at 250 K.

• Journal of the Korean Society of Clothing and Textiles
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• v.36 no.9
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• pp.928-939
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• 2012

This study evaluates wear comforts of water-vapor-permeable (WVP) garments through a measurement of various parameters such as skin and rectal temperatures, microclimate between skin and clothing, sweat rate, and subjective sensations (thermal, wet and comfort sensations) to correlate the physiological responses of the human body with its comfort feeling. Wear comfort during a specific exercise on a treadmill in a climatic chamber (temperature T = $20{\pm}0.5^{\circ}C$ and relative humidity H = $50{\pm}10%$) were studied using eight men wearing seven sportswear outfits (a long sleeve shirts and a long pants) made with seven different WVP fabrics. A comfort sensation was found to be highly correlated with skin T (p<.001), microclimate (T and H) between skin and clothing (p<.001) and sweat rate (p<.05). A regression model correlating comfort sensations and physiological responses obtained from wearer trials could be established: Y = 14.167 - 0.362 ${\times}$ X1 + 0.424 ${\times}$ X2 - 0.238 ${\times}$ X3 - 0.561 ${\times}$ X4 + 0.253 ${\times}$ X5 + 0.214 ${\times}$ X6 - 0.393 ${\times}$ X7 + 0.023 ${\times}$ X8 - 0.043 ${\times}$ X9. (Y = comfort sensation, X1 = forehead skin T, X2 = forearm skin T, X3 = hand skin T, X4 = thigh skin T, X5 = T of chest microclimate, X6 = T of thigh microclimate, X7 = chest sweat rate, X8 = H of back microclimate, X9 = H of thigh microclimate. The regression model obtained in this work can be used by manufacturers to objectively estimate the comfort sensation of sportswear before it is introduced to the consumer market. This study provides salient information to sportswear manufacturers and sportswear consumers.

• Journal of the Korean Chemical Society
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• v.33 no.5
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• pp.445-451
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• 1989

A series of solid solutions with formula $Er_{1-x}Sr_xFeO_{3-y}, where x is from 0.0 to 1.0, has been synthesized by heating at $1200^{\circ}C$ for 24 hours. X-ray diffraction shows these samples to be orthorhombically distorted perovskites for compositions up to x = 0. 6 and apparantly simple cubic perovskite structures from $0.8{\leq}x{\leq}1.0$. Lattice volumes are increased with the introduction of Sr. The mixed valence state of two kinds of Fe ion in these ferrite systems is analyzed by the Mohr salt titration method. Mossbauer spectra measured at room temperature for x = 0.0 and 0.5 compositions shows hyperfine splitting for iron (III) due to magnetic ordering and indicates that these samples contain octahedrally and tetrahedrally coordinated iron sites. Electrical conductivity measurements indicate that conduction in these samples apparantly occurs over the octahedral sites by a hopping mechanism.