• Journal of the Korean Crystal Growth and Crystal Technology
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• v.24 no.6
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• pp.229-236
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• 2014

A stoichiometric mixture of evaporating materials for $MnAl_2S_4$ single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films, $MnAl_2S_4$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the Hot Wall Epitaxy (HWE) system. The source and substrate temperatures were $630^{\circ}C$ and $410^{\circ}C$, respectively. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The temperature dependence of the energy band gap of the $MnAl_2S_4$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)=3.7920eV-5.2729{\times}10^{-4}eV/K)T^2/(T+786 K)$. In order to explore the applicability as a photoconductive cell, we measured the sensitivity (${\gamma}$), the ratio of photocurrent to dark current (pc/dc), maximum allowable power dissipation (MAPD) and response time. The results indicated that the photoconductive characteristic were the best for the samples annealed in S vapour compare with in Mn, Al, air and vacuum vapour. Then we obtained the sensitivity of 0.93, the value of pc/dc of $1.10{\times}10^7$, the MAPD of 316 mW, and the rise and decay time of 14.8 ms and 12.1 ms, respectively.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.6
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• pp.63-69
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• 2008

Reconfigurable RF one-chip solutions have been researched with the objective of designing for smaller-sized and more economical RF transceiver and it can be applied to a vehicular wireless terminal. The proposed voltage-controlled oscillator satisfies the targeted frequency range ($4.2{\sim}5.4\;GHz$) and the frequency planning which correspond to the standards such as CDMA(IS-95), PCS, GSM850, EGSM, WCDMA, WLAN, Bluetooth, WiBro, S-DMB, DSRC, GPS, and DVB-H/DMB-H/L(L Band). In order to improve phase noise performance, PMOS is adopted in the cross-coupled pair, the tail current source and MOS varactor in this VCO and differential-typed switching is proposed in capacitor array. Based on the measurement results, a total power dissipation is $5.3{\sim}6.0\;mW$ at 1.8 V power supply voltage. The oscillator is tuned from 4.05 to 5.62 GHz; The tuning range is 33%. The phase noise is -117.16 dBc/Hz at 1 MHz offset frequency and the FOM (Figure Of Merit) is $-180.84{\sim}-180.5$.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.49 no.8
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• pp.22-26
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• 2012

This paper introduces a 2.5-Gb/s optical receiver implemented in a standard 1P4M 0.18um CMOS technology for the applications of active optical HDMI cables. The optical receiver consists of a differential transimpedance amplifier(TIA), a five-stage differential limiting amplifier(LA), and an output buffer. The TIA exploits the inverter input configuration with a resistive feedback for low noise and power consumption. It is cascaded by an additional differential amplifier and a DC-balanced buffer to facilitate the following LA design. The LA consists of five gain cells, an output buffer, and an offset cancellation circuit. The proposed optical receiver demonstrates $91dB{\Omega}$ transimpedance gain, 1.55 GHz bandwidth even with the large photodiode capacitance of 320 fF, 16 pA/sqrt(Hz) average noise current spectral density within the bandwidth (corresponding to the optical sensitivity of -21.6 dBm for $10^{-12}$ BER), and 40 mW power dissipation from a single 1.8-V supply. Test chips occupy the area of $1.35{\times}2.46mm^2$ including pads. The optically measured eye-diagrams confirms wide and clear eye-openings for 2.5-Gb/s operations.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.2
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• pp.34-45
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• 2017

Cyclic loading tests for a total of nine test specimens were performed to evaluate the seismic performance of the exposed steel column-base plate connections. From the tests, flexural strength, deformation capacity, energy dissipation, and initial stiffness were investigated. The primary test parameters were the thickness of base-plate, embedment length of anchor bolt, the presence of hook, and rib plates. Test results showed that flexural behavior of column base-plate connection was substantially affected by the base-plate thickness, embedment length and the number of anchor bolts. On the other hand, the effect of rib plates on the increase of the flexural performance was not observed. The initial stiffness of the test specimens was about 15% of the flexural stiffness obtained by assuming that the support is fixed. As a result, even if the exposed column base-plate is designed in accordance with current design recommendations, in case that bond strength between concrete and the anchor bolts is not sufficient, the base-plate connection showed an unaccceptable load-displacement behavior.

• Korean Journal of Environmental Agriculture
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• v.33 no.4
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• pp.290-297
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• 2014

BACKGROUND: The current study purposed to analyse the dissipation levels of a neonicotinoid insecticide and clothianidin in paddy and upland soils and clarify the effects of soil moisture on degradation and persistence of the insecticide. METHODS AND RESULTS: In order to achieve the research purposes, clothianidin 8% SG was applied to the paddy and upland fields at the rate of 0.024 kg a.i./10a, while the analytical standard was treated at 0.25 mg/kg soil under laboratory conditions. Based on the multiple first-order kinetics, total clothianidin in soils was dissipated with $DT_{50}$ of 6.7-16.1 and 6.9-8.2 days in the paddy and upland fields, respectively, whereas the figures under the laboratory condition became larger showing 56.3 and 19.6 days. CONCLUSION: As affected by soil moisture, some differences in degradative pathways were observed. Flooding of soil caused evidently demethylation and delayed cyclization of a major metabolite, thiazolylmethylguanidine (TMG) and methylaminoimidazole(MAI), compared to the aerobic upland condition. More than 80% and 50% of the parent compound was dissipated by the 24th day after the final application in both soils and, transformation products had constituted most of soil residues after that.

• Journal of Food Hygiene and Safety
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• v.31 no.2
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• pp.67-73
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• 2016

Resveratrol is a non-flavonoid polyphenol which belongs to the stilbenes group and is naturally generated in several plants in response to damage or fungal invasion. It has been shown in published studies that resveratrol has an anti-adipogenic effect. A good consensus regarding the involvement of a down-regulation of $C/EBP{\alpha}$ and $PPAR{\gamma}$ in this effect has been reached. In addition, different metabolic pathways involved in triacylglycerol metabolism in white adipose tissue have been shown to be regulated by resveratrol. Concerning lipolysis, though this compound in itself seems to be unable to cause lipolysis, it increases lipid mobilization stimulated by ${\beta}-adrenergic$ agents. The increase in brown adipose tissue thermogenesis, and accordingly the associated energy dissipation, can attribute to accounting for the body-fat reducing effect of resveratrol. Besides its effects on adipose tissue, resveratrol can also acts on other organs and tissues. Therefore, it increases mitochondrial biogenesis and accordingly fatty acid oxidation in skeletal muscle and liver. This effect can also attribute to the body-fat reducing effect of this molecule. The present review purposes to collect the evidence concerning the potential mechanisms of action which underlie the anti-obesity effects of resveratrol, acquired either in cultured cells lines and animal models.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.10 s.352
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• pp.1-9
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• 2006

In this paper, a couple of 10Gb/s transimpedance amplifiers are realized in a 0.18um standard CMOS technology for optical communication applications. First, the voltage-mode inverter TIA(I-TIA) exploits inverter input configuration to achieve larger effective gm, thus reducing the input impedance and increasing the bandwidth. I-TIA demonstrates $56dB{\Omega}$ transimpedance gain, 14GHz bandwidth for 0.25pF photodiode capacitance, and -16.5dBm optical sensitivity for 0.5A/W responsivity, 9dB extinction ration and $10^{-12}$ BER. However, both its inherent parasitic capacitance and the package parasitics deteriorate the bandwidth significantly, thus mandating very judicious circuit design. Meanwhile, the current-mode RGC TIA incorporates the regulated cascade input configuration, and thus isolates the large input parasitic capacitance from the bandwidth determination more effectively than the voltage-mode TIA. Also, the parasitic components give much less impact on its bandwidth. RGC TIA provides $60dB{\Omega}$ transimpedance gain, 10GHz bandwidth for 0.25pF photodiode capacitance, and -15.7dBm optical sensitivity for 0.5A/W responsivity, 9dB extinction ration and $10^{-12}$ BER. Main drawback is the power dissipation which is 4.5 times larger than the I-TIA.

• Journal of the Korean Ceramic Society
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• v.34 no.2
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• pp.202-208
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• 1997

Bi-layered SrBi2Ta2O9(SBT) films were deposited on Pt/Ti/SiO2/Si sibstrates by rf magnetron sputt-ering at room temperature and then were annealed at 75$0^{\circ}C$, 80$0^{\circ}C$ and 85$0^{\circ}C$ for 1 hour in oxygen at-mosphere. The film composition of SrBi2Ta2O9 was obtained after depositing at room temperature and annealing at 80$0^{\circ}C$. Excess 20mole% Bi2O3 and 30 mole% SrCO3 were added to the target to compensate for the lack of Bi and Sr in SBT film. 200 nm thick SBT film exhibited and dense microstructure, adielectric constant of 210, and a dissipation factor of 0.05 at 1 MHz frequency. The films exhibited Curie temperature of 32$0^{\circ}C$ and a dielectric constant of 314 at that temperature under 100 kHz frequency. The remanent polarization(2Pr) and the coercive field(2Ec) of the SBT films were 9.1 $\mu$C/$\textrm{cm}^2$ and 85 kV/cm at an applied voltage of 3V, resspectively and the SBT film showed a fatigue-free characteristics up to 1010 cy-cles under 5V bipolar pulse. The leakage current density of the SBT film was about 7$\times$10-7A/$\textrm{cm}^2$ at 150 kV/cm. Fatigue-free SBT films prepared by rf magnetron sputtering can be suitable for application to non-volatile memory device.

• Journal of IKEEE
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• v.2 no.2 s.3
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• pp.278-284
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• 1998

This paper describes a l0b CMOS A/D converter (ADC) for HDTV applications. The proposed ADC adopts a typical multi-step pipelined architecture. The proposed circuit design techniques are as fo1lows: A selective channel-length adjustment technique for a bias circuit minimizes the mismatch of the bias current due to the short channel effect by supply voltage variations. A power reduction technique for a high-speed two-stage operational amplifier decreases the power consumption of amplifiers with wide bandwidths by turning on and off bias currents in the suggested sequence. A typical capacitor scaling technique optimizes the chip area and power dissipation of the ADC. The proposed ADC is designed and fabricated in s 0.8 um double-poly double-metal n-well CMOS technology. The measured differential and integral nonlinearities of the prototype ADC show less than ${\pm}0.6LSB\;and\;{\pm}2.0LSB$, respectively. The typical ADC power consumption is 119 mW at 3 V with a 40 MHz sampling rate, and 320 mW at 5 V with a 50 MHz sampling rate.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.9
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• pp.631-637
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• 2003

We have evaluated structural and electric, ferroelectric properties of PZT(30/70) thick film prepared by using 1,3-propanediol based sol-gel method on Pt/Ti/SiO$_2$/Si substrates. Rapid thermal annealing (RTA) is used to reduce the thermal stress and final furnace annealing is processed at $650^{\circ}C$. As the results of SEM analysis, we find that we get 350 nm in thickness for one coating and 1 $\mu$m for three times of coating. In the results of C-D analysis at 1 kHz, dielectric constant ($\varepsilon$$_{r}$) and dissipation factor were 886 and 0.03, respectively. C-V curve is shaped as a symmetrical butterfly. Leakage current density at 200 kV/cm is 1.23${\times}$10$^{-5}$ A/cm$^2$ and in the results of hysteresis loops measured at 150 kV/cm, the remnant polarization (P$_{r}$) and the coercive field (E$_{c}$) are 33.8 $\mu$C/cm$^2$ and 56.9 kV/cm, respectively. PZT(30/70) thick film exhibits relatively good ferroelectric, electric properties.s..