• Journal of IKEEE
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• v.14 no.1
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• pp.33-39
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• 2010

In this paper, a 5Gb/s receiver with an adaptive equalizer for serial link interfaces is proposed. For effective gain control, a least-mean-square (LMS) algorithm was implemented with two internal signals of slicers instead of output node of an equalizing filter. The scheme does not affect on a bandwidth of the equalizing filter. It also can be implemented without passive filter and it saves chip area and power consumption since two internal signals of slicers have a similar DC magnitude. The proposed adaptive equalizer can compensate up to 25dB and operate in various environments, which are 15m shield-twisted pair (STP) cable for DisplayPort and FR-4 traces for backplane. This work is implemented in $0.18-{\mu}m$ 1-poly 4-metal CMOS technology and occupies $200{\times}300{\mu}m^2$. Measurement results show only 6mW small power consumption and 2Gbps operating range with fabricated chip. The equalizer is expected to satisfy up to 5Gbps operating range if stable varactor(RF) is supported by foundry process.

• Journal of the Korean Solar Energy Society
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• v.31 no.2
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• pp.47-52
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• 2011

Currently, Exterior wall's U-value about building envelope is 0.36 W/$m^2K$(Central Region), but window's one is 2.1 W/$m^2K$ according to air gap of glazing, filling gas, coating and type of windows. The door"s one is 1.6~5.5 W/$m^2{\cdot}K$ depending on material and configuration of door. As such, energy loss per unit of door is considerably larger like windows. The door for the recognition was relatively low because energy loss through the door is relatively small compared to window area. In this paper, thermal performance was analyzed through simulation targeting the door which has thermal break that can improve the insulation performance and doesn't have one. As a results of simulations, case1 was calculated as the average of 1.63 w/m2k and case 2 was calculated as the average of 4.14 w/m2k. The thermal performance of door depends on the type and condition of insulations. As a results of final simulations, Case1 was calculated as 1.06 w/m2k and Case2 was calculated as 1.27 w/m2k. As a results of the experiments, thermal performance of case 1 was measured as 1.28 w/m2k. Error between experiments and simulations is considered problems encountered when creating the samples. The effect of door frame on the overall thermal performance is slight because it's a small proportion of the door frame.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.176-176
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• 2003

The effects of oxide thickness and gate length of MgO/GaN metal oxide semiconductor field effect transistors (MOSFETs) on I-V, threshold voltage and breakdown voltage characteristics were examined using a drift-diffusion model. The saturation drain current scales in an inverse logarithmic fashion with MgO thickness and is < 10$^{-3}$ A.${\mu}{\textrm}{m}$$^{-1}$ for 0.5 ${\mu}{\textrm}{m}$ gate length devices with oxide thickness > 600 $\AA$ or for all 1 ${\mu}{\textrm}{m}$ gate length MOSFETs with oxide thickness in the range of >200 $\AA$. Gate breakdown voltage is > 100 V for gate length >0.5 ${\mu}{\textrm}{m}$ and MgO thickness > 600 $\AA$. The threshold voltage scales linearly with oxide thickness and is < 2 V for oxide thickness < 800 $\AA$ and gate lengths < 0.6 ${\mu}{\textrm}{m}$. The GaN MOSFET shows excellent potential for elevated temperature, high speed applications.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.519-527
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• 1996

Most operation related to the application granular agrochemicals in korea are manual and labour consuming. As a multipurpose granular applicator, a pneumatic granular applicator that can be attached to conventional ride -on machines for paddy field was designed in this study. Experiments and simulations were carried out for determine in the design factors with one fertilizer (DongBu 21-17-17) and one pesticide (SamKong Ivi). The maximum terminal velocity of granular chemicals was estimated as 14.2m/s. A better distribution pattern was obtained at the diffuser having only deflectors without dividing guides. The diffuser spacing 1.0m for the fertilizer and the diffuser spacing 0.8m for the pesticide at the boom height over 0.80m were acceptable for the uniform distribution. In the case that the forward speed of ride-on machines was 0.7m/s, the groove opening and the roller speed of the selected metering device were13mm -15mm at 2 rps for the fertilizer, and 9 mm-11mm at 0.25rps or the pesticide. This study suggested a method of developing a pneumatic applicator for granular agrochemicals.

• Journal of Hydrogen and New Energy
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• v.30 no.5
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• pp.418-427
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• 2019

Activated carbon was synthesized from bamboo charcoal by KOH activation at various temperatures for electrochemical double layer capacitor applications. The micro-structural and surface properties of all the samples were characterized by X-ray diffraction, scanning electron microscopy and N2 adsorption/desorption isotherm method. The electrochemical properties of the activated bamboo charcoal were examined by cyclic voltammetry in the potential window of -1.0 to 0.2 V in 6 M KOH electrolyte at different scan rates. An electrode made from the sample activated with 7.5 M KOH and heat treated at $750^{\circ}C$ for 3 h gave a maximum capacitance of 553 F/g at 1 mV/s and 450 F/g at 10mV/s.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.1
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• pp.67-74
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• 2000

Recently, PTFE-polymide composites are being used self-lubricating parts for industrial field. Thus, this study is mainly concerned with friction and wear properties for the piston ring of non-lubricating air compressor which made of PTFE-polymide composites. The friction and wear test was carried out for the different composition ratio under the atomsphere room temperature and constant load of 7.69N and their friction and wear properties were compared with each other at various sliding speed. notable results are summarized as follows. PTFE 100% showed that friction coefficient was almost same values at 0.94 and 1.88m/s but the value was decreased at 2.83m/s because the friction temperature is higher than low speed. PTFE 80%-PI 20% showed the lowest mean friction coefficient at 2.83m/s. PTFE 20-PI 80% showed the highest friction coefficient at 0.94m/s and the value was decreased at high speed but the value is higher than other materials except PTFE 100 %. PI 100% showed the highest friction coefficient at 0.94 and 1.88m/s becuase adhesive wear mainly occurred that speed. PTFE 100% showed highest specific wear rate on the whole. Specific wear rate of PTFE 80%-PI 20% was almost the same value with PTFE 20%-PI80%. PI 100%showed the lowest value at high sliding speed because the friction surface was thicken and carbonated by high friction temperature.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.12 s.189
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• pp.103-110
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• 2006

The rail clamp is very important device to prevent that a container crane slips along a rail due to the wind blast as well as to locate the crane in the set position during an operating mode. Recently, the design wind speed criteria were intensified from the wind speed of 16m/s to 35m/s during an operating mode, and from 50m/s to 75m/s during a stowed mode in Korea, according to the 'Inspection Criteria for Facilities and Equipments in Port' reformed after typhoon 'Maemi'. In order to design the wedge type rail clamp for the reinforced design wind speed criteria of 35m/s, we carried out the finite element analysis of the rail clamp with respect to the wedge angle, and analyzed the relationship between the wedge angle and the sliding distance of the rail clamp.

• Journal of Power Electronics
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• v.12 no.5
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• pp.821-829
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• 2012

This research article presents a novel approach based on an instantaneous active and reactive power component (p-q) theory for generating reference currents for shunt active filter (SHAF). Three-phase reference current waveforms generated by proposed scheme are tracked by the three-phase voltage source converter in a hysteresis band control scheme. The performance of the SHAF using the p-q control strategy has been evaluated under various source conditions. The performance of the proposed control strategy has been evaluated in terms of harmonic mitigation and DC link voltage regulation. In order to maintain DC link voltage constant and to generate the compensating reference currents, we have developed Fuzzy logic controller with different (Trapezoidal, Triangular and Gaussian) fuzzy M.F.s. The proposed SHAF with different fuzzy M.F.s is able to eliminate the uncertainty in the system and SHAF gains outstanding compensation abilities. The detailed simulation results using MATLAB/SIMULINK software are presented to support the feasibility of proposed control strategy. To validate the proposed approach, the system is also implemented on a real time digital simulator and adequate results are reported for its verifications.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.6
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• pp.317-322
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• 2016

While PFOS sodium salt ($C_8F_{17}SO_3Na$) was not degraded by microorganisms for 28 days, the 4 alternatives were biodegraded at the rates of 21.6% for $C_{25}F_{17}H_{32}S_3O_{13}Na_3$, 20.5% for $C_{15}F_9H_{21}S_2O_8Na_2$, 15.8% for $C_{23}F_{18}H_{28}S_2O_8Na_2$ and 6.4% for $C_{17}F_9H_{25}S_2O_8Na_2$, respectively. The acute toxicity test using Daphnia magna was conducted for 48 hours, the half effective concentration ($EC_{50}$) of PFOS sodium salt ($C_8F_{17}SO_3Na$) was evaluated in 54.5 mg/L. While the 4 alternatives did not show any effect at 500.0 mg/L. The surface tension of the PFOS salt ($C_8F_{17}SO_3Na$) is 46.2 mN/m at a concentration of 500.0 mg/L. While the surface tension of the 4 alternatives was found to be superior to PFOS sodium salt ($C_8F_{17}SO_3Na$). The surface tension of $C_{23}F_{18}H_{28}S_2O_8Na_2$ (20.9 mN/m) has the lowest, followed by $C_{15}F_9H_{21}S_2O_8Na_2$ (23.4 mN/m), $C_{17}F_9H_{25}S_2O_8Na_2$ (27.3 mN/m), $C_{25}F_{17}H_{32}S_3O_{13}Na_3$ (28.2 mN/m). The four kinds of alternatives ($C_{15}F_9H_{21}S_2O_8Na_2$, $C_{17}F_9H_{25}S_2O_8Na_2$, $C_{23}F_{18}H_{28}S_2O_8Na_2$, $C_{25}F_{17}H_{32}S_3O_{13}Na_3$) were found to be superior to PFOS sodium salt ($C_8F_{17}SO_3Na$) in terms of biodegradation, Daphnia sp. acute toxicity and surface tension, and thus they were considered applicable as PFOS alternatives. Especially biodegradation rate of $C_{15}F_9H_{21}S_2O_8Na_2$, $C_{23}F_{18}H_{28}S_2O_8Na_2$ and $C_{25}F_{17}H_{32}S_3O_{13}Na_3$ was relatively high as 15.8~21.6%, and Daphnia sp. acute toxicity and surface tension were considerably superior (surface tension 39~55%) to PFOS sodium salt. Therefore, these alternatives are considered to be available as an alternative of PFOS.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.323-324
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• 2012