• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.9 s.180
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• pp.2319-2325
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• 2000

This thesis studied that seven kinds of residual elements(inclusions) had influenced on fracture toughness($K_{IC}$) obtained by Begley-Logsdon and Rolfe-Novak model equation using tensile an d impact test data of I%CrMoV HP(high pressure) rotor steel. $K_{IC}$ design curve of ASME and fracture surface by SEM were also considered, obtained results are summarized as follows $K_{IC}$ was linearly increased with increase of temperature, effect of the inclusions was significantly over FATT. $K_{IC}$ at lower shelf temperature was quantitatively related to yield strength and was agreed well with Begley's equation. It was difficult to determine $K_{IC}$ because of specimen size and tester capacity at upper shelf temperature, but for this view point Rolfe-Novak's equation was useful. The degree of brittle fracture was dependent on FATT fundamentally, adding S, Sb to matrix decreased impact energy and adding Cu, As increased yield(tensile) strength, and the influence of the others minority inclusion was comparatively insignificant.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2577-2579
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• 2002

In this paper, we describe a CMOS DC-DC converter with a variable output voltage(8-12V @100mA) for a portable battery-operated system applications. The proposed DC-DC converter is used along with a Pulse-Frequency Modulation (PFM) method and consists of a reference circuit, a feedback resistor, a controller, and an internal oscillator. The integrated DC-DC converter with two external passive components(L.C) has been designed and fabricated on a 0.6${\mu}m$ 2-poly, 3-metal CMOS process and could be applied to the Personal Digital Assistants(PDA), Cellular Phone, Laptop Computer, etc.

• JSTS:Journal of Semiconductor Technology and Science
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• v.5 no.4
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• pp.276-281
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• 2005

This paper presents a low voltage operating IF QPSK receiver block which is consisted of programmable gain amplifier (PGA) and analog to digital converter. This PGA has 6 bit control and 250MHz bandwidth, $0{\sim}20\;dB$ gain range. Using the proposed PGA architecture (low distortion gain control switch block), we can process the continuous fully differential $0.2{\sim}2.5Vpp$ input/output range and 44MHz carrier with 2 MHz bandwidth signal at 1.8V supply voltage. Using the sub-sampling technique (input freq. is $44{\sim}46MHz$, sampling freq. is 25MHz), we can process the IF QPSK signal ($44{\sim}46MHz$) which is the output of the 6 bit PGA. We can get the SNDR 35dB, which is the result of PGA and ADC at full gain mode. We fabricated the PGA and ADC and the digital signal processing block of the IF QPSK with the 0.18um CMOS MIM process 1.8V Supply.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.1
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• pp.28-37
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• 2010

In this paper, the IC (Integrated Circuit) for multi-channel asynchronous communication was designed by using FPGA and VHDL language. The existing chips for asynchronous communication that has been used commercially are composed of one to two channels. Therefore, when communication system with two channels or more is made, the cost becomes high and it becomes complicated for communication system to be realized and also has very little buffer, load that is placed into Microprocessor increases heavily in case of high speed communication or transmission of high-capacity data. The designed IC was improved the function and performance of communication system and reduced costs by designing 8 asynchronous communication channels with only one IC, and it has the size of transmitter/receiver buffer with 256 bytes respectively and consequently high speed communication became possible. To detect errors between communications, it was designed with digital filter and check-sum logic and channel MUX logic so that the malfunction can be prevented and errors can be detected more easily and input/output port regarding each communication channel can be used flexibly and consequently the reliability of system was improved. It was composed and simulated logic of VHDL described by using Cyclone II Series EP2C35F672C8 and QuartusII V8.1 of ALTERA company. In order to show the performance of designed IC, the test was conducted successfully in QuartusII simulation and experiment and the excellency was compared with TL16C550A of TI (Texas Instrument) company and ATmegal28 general-purpose micro controller of ATMEL company that are used widely as chips for asynchronous communication.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.8
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• pp.38-48
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• 2014

In this paper, a design of Signal Processing Analog Front-End IC for Automotive Piezo-Resistive Type Pressure Sensor is presented. In modern society, as the car turns to go from mechanical to electronic technology, the accuracy and reliability of electronic parts required importantly. In order to improve these points, Programmable Gain Amplifier (PGA) amplifies the received signal in accordance with gain for increasing the accuracy after PRT Sensor is operated to change physical pressure signals to electrical signals. The signal amplified from PGA is processed by Digital blocks like ADC, CMC and DAC. After going through this process, it is possible to determine the electrical signal to physical pressure signal. As processing analog signal to digital signal, reliability and accuracy in Analog Front-End IC is increased. The current consumption of IC is 5.32mA. The die area of the fabricated IC is $1.94mm{\times}1.94mm$.

• Proceedings of the KIEE Conference
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• 1997.07a
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• pp.364-366
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• 1997

This paper is investigated about the IC-card being expanded gradually, and will be presented the probability applying to fare collection system of railway. To become an intelligent system for railway system, it is necessary to acquire the information for the passengers by non-contact method.

• Proceedings of the KIEE Conference
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• 2000.11b
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• pp.355-357
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• 2000

Measurement used electricsal sounding(MacOHM 2115, Japan) for grounding resistance of Jung-Bu highway Ha-Nam IC about 500m. To applied measurement method is fall of potential method and analysis earth resistivity used ESII(Electrical Sounding Interactive Interpretation) program. This result propose for construction plan of electric corrosion.

• Journal of Life Science
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• v.15 no.5 s.72
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• pp.796-801
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• 2005

For usage of natural antioxidants, sanjook (Sasa boreails var. chiisanensis) leaves were extracted with methanol and investigated about its antioxidative activities and stability. It showed that the antioxidant activity of methanol extracts from the leaves of sanjook depend on their concentration within range of 0.1 to 0.8 mg/ml. The methanol extracts from the leaves of sanjook represented $583{\mu}g/ml$ for $IC_{50}$ of DPPH radical scavenging ability, $800{\mu}g/ml$for $IC_{50}$ of SOD-like activity and $38{\mu}g/ml$for $IC_{50}$ of $H_{2} O_{2}$ scavenging ability, while BHT, as a compared substance, was $271{\mu}g/ml$ for $IC_{50}$ of DPPH radical scavenging ability, $680{\mu}g/ml$ for $IC_{50}$ of SOD-like activity and $30{\mu}g/ml$ for $IC_{50}$ of $H_{2} O_{2}$ scavenging ability, respectively. The anti-au-toxidation effect for methanol extracts from the leaves of sajook was $55\∼60\%$ within range of 0.1 to 0.8 mg/ml. The pH stability on methanol extracts from the leaves of sanjook was most stable at pH 6. The more acid or akali it became, the more unstable it turned. The thermostability on methanol extracts from the leaves of sanjook remained above $80\%$ of their DPPH activity at range of $0^{\circ}C{\;}to{\;}120^{\circ}$.

• Journal of Korean Society of Transportation
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• v.30 no.3
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• pp.31-41
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• 2012

Due to growing interests in the distribution of traffic volume through information dissemination such as VMS and traffic broadcasting system, the research on the driver's reaction and effect of the traffic report has continued. In this study, we propose a methodology, which estimates the traffic volume of diversion and the consequential diversion rate using FTMS data and TCS data, and the estimation is based on the analysis of the national highway and IC, in which real-time FTMS and TCS data are established. We also calculate the diversion rate of actual targeted sections and analyze the changes in time and spatial diversion rate. In this study, we define a deviation (considering a deviation due to dynamic properties of traffic conditions) found when the outflow traffic volume is temporarily higher than the average outflow traffic volume on a relevant time slot after providing traffic information. The diverting volume is considered to be caused by the traffic information, and the study determines the ratio of traffic volume on highways to that of route diversion as the diversion rate. The analysis on changes in the diversion rate in accordance with the time flow, the initial change in the diversion rate on upstream IC that first acquires the report on the traffic congestion is significant. After that, the change in the diversion rate on upstream IC affects the route diversion on downstream IC with spatial and time flow, and this again leads the change in upstream IC. Thereby, we confirmed that there is a feedback-control circulation system in the route diversion.

• Journal of the Korean Chemical Society
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• v.43 no.4
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• pp.461-468
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• 1999

Acetolactate synthase (ALS) catalyzes the first common reaction in the biosynthesis of branched-chain amino acids, valine, leucine, and isoleucine. ALS is the common target of several classes of structurally diverse herbicides, the triazolopyrimidines, the imidazolinones, the sulfonylureas, and pyrimidyl-oxy-benzoates. We examined ihibitory activities of newly synthesized triazolopyrimidine sulfonamide derivatives using partially purified ALS from barley. $IC_{50}$ values for the active derivatives are 0.5nM∼8$\mu$M. Among them TP1 and TP2 are the most potent ALS inhibitors with $IC_{50}$ values of 0.5nM and 1.6nM, respectively. These inhibitors are more potent in the inhibition of barley ALS than commercial herbicides, Metosulam ($IC_{50}$;3.6 nM), Flumetsulam ($IC_{50}$;126 nM), and Cadre ($IC_{50};4 {\mu}M$). The progress curves for inhibition of ALS by TP2 showed that the amount of inhibition increases with time. The inhibition of ALS by TP2 was mixed-type inhibition with respect to pyruvate. Dual inhibition analyses of TP2 versus an imidazolinone, Cadre, and Leu showed parallel and intercepting kinetic pattern, respectively. The results suggest that TP2 binds to ALS competively with Cadre but not with Leu. Chemical modification of cysteinly residues in ALS decreased the sensitivity of ALS to Leu, while the modification did not affect the sensitivity of ALS to TP2 and Cadre.