• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.3
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• pp.60-68
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• 2009

This work proposes a 10b 200MS/s 65nm CMOS ADC for high-definition video systems such as HDTV requiring high resolution and fast operating speed simultaneously. The proposed ADC employs a four-step pipeline architecture to minimize power consumption and chip area. The input SHA based on four capacitors reduces the output signal range from $1.4V_{p-p}$ to $1.0V_{p-p}$ considering high input signal levels at a low supply voltage of 1.2V. The proposed three-stage amplifiers in the input SHA and MDAC1 overcome the low output resistance problem as commonly observed in a 65nm CMOS process. The proposed multipath frequency-compensation technique enables the conventional RNMC based three-stage amplifiers to achieve a stable operation at a high sampling rate of 200MS/s. The conventional switched-bias power-reduction technique in the sub-ranging flash ADCs further reduces power consumption while the reference generator integrated on chip with optional off-chip reference voltages allows versatile system a locations. The prototype ADC in a 65nm CMOS technology demonstrates a measured DNL and INL within 0.19LSB and 0.61LSB, respectively. The ADC shows a maximum SNDR of 54.BdB and 52.4dB and a maximum SFDR of 72.9dB and 64.8dB at 150MS/S and 200MS/s, respectively. The proposed ADC occupies an active die area of $0.76mm^2$ and consumes 75.6mW at a 1.2V supply voltage.

• Korean Journal of Remote Sensing
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• v.37 no.5_2
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• pp.1295-1305
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• 2021

Satellite-derived ocean color products are required to effectively monitor clear open ocean and coastal water regions for various research fields. For this purpose, accurate correction of atmospheric effect is essential. Currently, the Geostationary Ocean Color Imager (GOCI)-II ground segment uses the reanalysis of meteorological fields such as European Centre for Medium-Range Weather Forecasts (ECMWF) or National Centers for Environmental Prediction (NCEP) to correct gas absorption by water vapor and ozone. In this process, uncertainties may occur due to the low spatiotemporal resolution of the meteorological data. In this study, we develop water vapor absorption correction model for the GK-2 combined GOCI-II atmospheric correction using Advanced Meteorological Imager (AMI) total precipitable water (TPW) information through radiative transfer model simulations. Also, we investigate the impact of the developed model on GOCI products. Overall, the errors with and without water vapor absorption correction in the top-of-atmosphere (TOA) reflectance at 620 nm and 680 nm are only 1.3% and 0.27%, indicating that there is no significant effect by the water vapor absorption model. However, the GK-2A combined water vapor absorption model has the large impacts at the 709 nm channel, as revealing error of 6 to 15% depending on the solar zenith angle and the TPW. We also found more significant impacts of the GK-2 combined water vapor absorption model on Rayleigh-corrected reflectance at all GOCI-II spectral bands. The errors generated from the TOA reflectance is greatly amplified, showing a large error of 1.46~4.98, 7.53~19.53, 0.25~0.64, 14.74~40.5, 8.2~18.56, 5.7~11.9% for from 620 nm to 865 nm, repectively, depending on the SZA. This study emphasizes the water vapor correction model can affect the accuracy and stability of ocean color products, and implies that the accuracy of GOCI-II ocean color products can be improved through fusion with GK-2A/AMI.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.8
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• pp.565-571
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• 2003

We prepare the PVDF thin film using vacuum deposition method with the application of voltage and obtain the optimum deposition condition for $\beta$-PVDF thin film on the basis of the results of FT-IR, crystallinity of $\beta$ phase, surface roughness studies with varying the condition. The phase of PVDF thin film is analyzed by the FT-IR spectrum. When the substrate temperature and applied voltage increase from 3$0^{\circ}C$ to 9$0^{\circ}C$ and from 0kV to 9kV, respectively, the crystallinity of $\beta$ phase is introduced as large as 64%. It means that the substrate temperature and applied voltage allow the phase transition of $\beta$ phase to occur more easily. Also, the surface roughness of PVDF thin film decreases from 65.1nm to 36.6nm with the increase of substrate temperature. In results, we obtain the optimum deposition conditions for $\beta$-PVDF thin film from these experimental results and measure the Properties of the $\beta$-PVDF film deposited in the optimum condition. The dielectric properties such as dielectric constant and loss tangent decrease from 2.34 to 0.44 and from 0.27 to 0.04 with the increase of frequency, respectively.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.6
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• pp.509-518
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• 2023

In this paper, we designed a 4Kb poly-fuse OTP IP (Intellectual Property) required for analog circuit trimming and calibration. In order to reduce the BL resistance of the poly-fuse OTP cell, which consists of an NMOS select transistor and a poly-fuse link, the BL stacked metal 2 and metal 3. In order to reduce BL routing resistance, the 4Kb cells are divided into two sub-block cell arrays of 64 rows × 32 rows, with the BL drive circuit located between the two 2Kb sub-block cell arrays, which are split into top and bottom. On the other hand, in this paper, we propose a core circuit for an OTP cell that uses one poly-fuse link to one select transistor. In addition, in the early stages of OTP IP development, we proposed a data sensing circuit that considers the case where the resistance of the unprogrammed poly-fuse can be up to 5kΩ. It also reduces the current flowing through an unprogrammed poly-fuse link in read mode to 138㎂ or less. The poly-fuse OTP cell size designed with DB HiTek 90nm CMOS process is 11.43㎛ × 2.88㎛ (=32.9184㎛2), and the 4Kb poly-fuse OTP IP size is 432.442㎛ × 524.6㎛ (=0.227mm²).

• Current Photovoltaic Research
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• v.7 no.4
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• pp.97-102
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• 2019

Bifacial and semitransparent hydrogenated amorphous silicon (a-Si:H) thin-film solar cells in p-i-n configuration were prepared with front and rear transparent conducting oxide (TCO) electrodes using plasma-enhanced chemical vapor deposition method. Fluorine-doped tin oxide and tin-doped indium oxide films were used as front and rear TCO contacts, respectively. Film thickness of intrinsic a-Si:H absorber layers were controlled from 150 nm to 450 nm by changing deposition time. The dependence of performance characteristics of solar cells on the front and rear illumination direction were investigated. For front illumination, gradual increase in the short-circuit current density (J_SC) from 10.59 mA/㎠ to 14.19 mA/㎠ was obtained, whereas slight decreases from 0.83 V to 0.81 V for the open-circuit voltage (V_OC) and from 68.43% to 65.75% for fill factor (FF) were observed. The average optical transmittance in the wavelength region of 380 ~ 780 nm of the solar cells decreased gradually from 22.76% to 15.67% as the absorber thickness was changed from 150 nm to 450 nm. In case of the solar cells under rear illumination condition, the J_SC increased from 10.81 to 12.64 mA/㎠ and the FF deceased from 66.63% to 61.85%, while the V_OC values were maintained at 0.80 V with increasing the absorber thickness from 150 nm to 450 nm. By optimizing the deposition parameters, a high-quality bifacial and semitransparent a-Si:H solar cell with 350 nm-thick i-a-Si:H absorber layer exhibited the conversion efficiencies of 7.69% for front illumination and 6.40% for rear illumination, and average visible optical transmittance of 17.20%.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2006.10a
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• pp.64-67
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• 2006

RF 스퍼터링법을 이용하여 AZO(Al 2wt%, ZnO 98wt%)박막을 glass위에 증착한 후 증착 시간과 증착 압력에 따른 면저항, roughness 및 광투과도를 조사하였다. 본 연구에서 AZO박막의 면 저항은 4-point probe(Guardian, 402S)으로 측정하였으며 광투과도는 IR-VIS-UV spectrophotometer로 측정하였다. AZO 박막을 20분 증착하는 동안, 아르곤 flow양이 50, 100, 150sccm일 때 면저항은 $20\;{\Omega}/{\square}$이고, 200sccm일 때 $3744\;{\Omega}/{\square}$였다. AZO 박막의 두께를 일정하게 증착하는 동안, 아르곤 flow양이 50sccm일 때 면저항은 $49.6\;{\Omega}/{\square}$이고 100, 150, 200sccm일 때 $38{\Omega}/{\square}$였으며, 광투과도는 모두 80%이상을 보였다. Roughness는 각각 4.1nm, 7.6nm, 5.2nm, 16.9nm였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.230-233
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• 2004

The stochiometric mix of evaporating materials for the $CuInS_2$ single crystal thin films was prepared from horizontal furnance. Using extrapolation method of X-ray diffraction patterns for the $CuInS_2$ polycrystal, it was found tetragonal structure whose lattice constant $a_0$ and $c_0$ were $5.524\;{\AA}$ and $11.142\;{\AA}$, respectively. To obtain the single crystal thin films, $CuInS_2$ mixed crystal was deposited on throughly etched semi-insulator GaAs(100) substrate by the hot wall epitaxy (HWE) system. The source and substrate temperature were 640 t and 430 t, respectively and the thickness of the single crystal thin films was $2{\mu}m$. Hall effect on this sample was measured by the method of van dot Pauw and studied on carrier density and temperature dependence of mobility. The carrier density and mobility deduced from Hall data are $9.64{\times}10^{22}/m^3,\;2.95{\times}10^{-2}\;m^2/V{\cdot}s$ at 293 K, respectively The optical energy gaps were found to be 1.53 eV at room temperature. From the photocurrent spectrum by illumination of perpendicular light on the c - axis of the thin film, we have found that the values of spin orbit coupling splitting ${\Delta}So$ and the crystal field splitting ${\Delta}Cr$ were 0.0211 eV and 0.0045 eV at 10 K, respectively. From PL peaks measured at 10K, 807.7nm (1.5350ev) mean Ex peak of the free exciton emission, also 810.3nm (1.5301eV) expresses $I_2$ peak of donor-bound exciton emission and 815.6nm (1.5201eV) emerges $I_1$ peak of acceptor-bound exciton emission. In addition, the peak observed at 862.0nm (1.4383eV) was analyzed to be PL peak due to donor-acceptor pair(DAP).

• Korean Journal of Microbiology
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• v.50 no.1
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• pp.53-59
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• 2014

This study was conducted to investigate the characteristics between non-fermented chinese yam and rice (non-FCYR) and fermented chinese yam and rice (FCYR). 1.1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, total polyphenol, flavonoid contents and reducing power were investigated to evaluate the anti-oxidation activities of FCYR. Also, productivity of monacolin K, major medicinal ingredient of FCYR, was investigated, using Aspergillus terreus KCCM 12225. In case of non-FCYR, DPPH radical scavenging activities for three kinds of yam (Dioscorea japonica, Dioscorea batatas, Dioscorea opposita) and rice were estimated about 51.8, 66.4, 42.2 and 7.5%, while in case of FCYR, those for three kinds of yam and rice were estimated to increased about 64.7, 74.7, 52.8, and 32.3%, respectively. Total polyphenol contents of non-FCYR were estimated to 196.9, 265.7, 160.1, and 91.6 mg/kg, while total polyphenol contents of FCYR were estimated to increase about 530.7, 708.3, 427.2, and 265.9 mg/kg, respectively. Total flavonoid contents of FCYR increased to 2.8-3.3 times higher than those of non-FCYR. Reducing power of non-FCYR was about 0.97, 1.28, 0.64, and 0.17 (OD at 700 nm), while, that of FCYR increased about 1.75, 2.38, 1.24, and 0.46. Remakable increase in monacolin K productivity of FCYR was observed. Monacolin K productivity of FCYR was estimated to 467.1, 514.8, 339.2, and 272.5 mg/kg, respectively. In this study, fermented chinese yam (Dioscorea batatas) was estimated to be effective biological activity material.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.9
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• pp.1847-1855
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• 2012

A 1V 1.6-GS/s 6-bit flash analog-to-digital converter (ADC) with a clock calibration circuit is proposed. A single track/hold circuit with a bootstrapped analog switch is used as an input stage with a supply voltage of 1V for the high speed operation. Two preamplifier-arrays and each comparator composed of two-stage are implemented for the reduction of analog noises and high speed operation. The clock calibration circuit in the proposed flash ADC improves the dynamic performance of the entire flash ADC by optimizing the duty cycle and phase of the clock. It adjusts the reset and evaluation time of the clock for the comparator by controlling the duty cycle of the clock. The proposed 1.6-GS/s 6-bit flash ADC is fabricated in a 1V 90nm 1-poly 9-metal CMOS process. The measured SNDR is 32.8 dB for a 800 MHz analog input signal. The measured DNL and INL are +0.38/-0.37 LSB, +0.64/-0.64 LSB, respectively. The power consumption and chip area are $800{\times}500{\mu}m2$ and 193.02mW.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.3
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• pp.454-458
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• 2014

In this study, we examined the ionization rate and permeability of nanocalcium prepared from oyster shells with various particle sizes. Four particle sizes of the calcium samples were prepared by centrifugation according to their density disparity in alcoholic solution: NC (normal calcium), C-1 (supernatant of 1,000 rpm), C-2 (supernatant of 2,000 rpm), and C-3 (supernatant of 3,000 rpm). Particle sizes of NC, C-1, C-2, and C-3 were $2,280.3{\pm}64.3nm$, $521.3{\pm}83.3nm$, $313.9{\pm}29.5nm$, and $280.0{\pm}3.4nm$, respectively. C-3 showed a slight increase in ionization rate compared with the other calcium samples, but their differences were not significant. Dialysis membrane-employed analysis showed that nanocalcium permeability increased as its particle size smaller; 32% of C-3 nanocalcium was transported to the outside of the membrane, whereas C-1 showed a 25% transport rate. We determined the permeability of the nanocalciums by using rat intestinal sacs, in order to provide different intestinal environments depending on pH level. Nanocalcium generally showed a higher permeability at pH 7, which represents an ileum environments compared to the duodenum and jejunum environments at pH 4.2 and pH 6.2, respectively. However, C-3 calcium showed the highest permeability, followed by C-2, C-1 and NS calciums. This result shows that the size of calcium positively affected its permeability in the intestinal sac. Taken together, nano-sized calcium derived from discarded oyster shell shows improved permeability in intestinal environments.