• Digital Contents
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• no.12 s.151
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• pp.21-29
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• 2005

DC산업이 차세대 국가성장동력인것은 분명하지만 업종별로 구분했을때 명암이 엇갈리는 것은 어쩔수 없는 세상이치인가보다. 올해도 이러한 현상은 여전했다. 상승세가 다소 꺾였다고는 하지만 여전히 온라인 게임분야가 전체시장을 주도한 가운데 패키지 게임·e러닝·DC솔루션분야는 새로운 수요를 찾기위한 관련업계의 움직임이 분주했다. 또한 올해 DC업계에서는 이통사들의 음악서비스 시장진출과 소리바다의 P2P 서비스중단등의 이슈로 온라인 음악시장이 출렁거렸고‘ 한류’의 바람을 타고 디지털 영상분야에서도 가능성을 확인했다.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.21-24
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• 1987

A novel type of the sinusoidal dc-to-ac converter is presented, where a pair of switches is placed in each side of the primary and the secondary of the isolation transformer. This converter is controlled by the phase difference between the two pairs of switches. As a result, the transformer is miniaturized by making the switching frequency high and the reactive energy can be easily recovered to the dc-source. This converter is especially suitable for small UPS systems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.10
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• pp.2653-2659
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• 1996

In this paper, DC-free and minimum bandwidth binary line codes with look-up table are proposed and their performances are analyzed. As results of performance analysis, the proposed codes are shown to have spectral nulls at DC and Nyquist frequency. Among the proposed codes, binary line codes of which both codeword digital sum and alternating digital sum are zero have lower code rate but better spectral characteristics. Furthermore, binary line codes which consist of all codewords including those with nonzero digital sum and alternating digital sum have worese spectral characteristics but higher code rate.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.2
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• pp.719-724
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• 2012

This study aimed to investigate the clinical significance of expression and amplification of decoy receptor 3 (DcR3) in pancreatic carcinomas (PC). mRNA expression was detected by PQ-PCR, and amplification was determined. DcR3 protein expression was detected by immunohistochemistry and ELISA. Correlations between DcR3 expression and clinical pathological factors were analyzed. The relative amount of DcR3 in PC tissues and non-cancerous tissues showed a statistically significant difference, 21 cases displaying more than two fold DcR3 amplification, while no such amplification was found in normal pancreatic tissues. DcR3 positive cell staining was located in the cytoplasm. The positive rate of DcR3 in PC and non-cancerous tissues showed a significant difference. DcR3 mRNA expression was correlated with clinical staging, size of the tumor, lymph node metastasis and histological staging, while protein expression was correlated with clinical data like tumor size. DcR3 gene amplification only correlated with tumor size. The level of DcR3 in serum of the PC resectable group before operation was $72.2{\pm}10.2$ pg/ml, showing a significant difference compared to gallbladder carcinoma group (GC) or pancreatic benign tumor (PBT) group (P < 0.01). In conclusion, DcR3 amplification is correlated with DcR3 expression in PC tissues, especially those clinical pathological factors which reflect tumor progression. Assessment of DcR3 level in sera of PC patients may be helpful for the early diagnosis and prognostic judgement.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.21-26
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• 2016

This paper presents a step-down DC-DC buck converter with a CCM/DCM dual-mode function for the internal power stage of portable electronic device. The proposed converter that is operated with a high frequency of 1 MHz consists of a power stage and a control block. The power stage has a power MOS transistor, inductor, capacitor, and feedback resistors for the control loop. The control part has a pulse width modulation (PWM) block, error amplifier, ramp generator, and oscillator. In this paper, an external capacitor for compensation has been replaced with a multiplier equivalent CMOS circuit for area reduction of integrated circuits. In addition, the circuit includes protection block, such as over voltage protection (OVP), under voltage lock out (UVLO), and thermal shutdown (TSD) block. The proposed circuit was designed and verified using a $0.18{\mu}m$ CMOS process parameter by Cadence Spectra circuit design program. The SPICE simulation results showed a peak efficiency of 94.8 %, a ripple voltage of 3.29 mV ripple, and a 1.8 V output voltage with supply voltages ranging from 2.7 to 3.3 V.

• Environmental Analysis Health and Toxicology
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• v.21 no.2 s.53
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• pp.139-146
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• 2006

The purpose of this study was to investigate the effects of dietary chungguajang powder on blood glucose level and hepatic activities of antioxidant enzymes in normal and streptozotocin (STZ)-induced diabetic rats. Sprague-Dawley male ratt ($200{\sim}220g$) of six groups including normal group fed normal diet (N), diabetic group fed normal diet (C), diabetic groups fed chunggugjang powder diet (DC-1%, DC-5%, DC-10%, DC-20%) were used for the experiments. Diabetes was induced by single intraperitoneal injection of streptozotocin as a dose of 70 mg/kg body weight. After 3 weeks the animals were sacrificed and hepatic activities of antioxidant enzymes, serum level of glucose and organ weight were evaluated. Food and water intakes were higher in diabetic groups than normal group. Body weight gain and food efficiency ratio were lower in diabetic groups. However, they were higher in chunggugjang diet groups (DC) than normal diet group (C). The serum glucose levels were significantly lower (p<0.05) in the diabetic groups fed chunggugjang diet (DC-10%, DC-20%) than diabetic group fed normal diet (C). Hepatic activities of superoxide dismutase, catalase, glutathione peroxidase and glutathione S-transferase were lower in diabetic groups than normal group and they were significantly lower in diabetic groups fed chunggugjang diet (DC-20%) compared to diabetic rats fed normal diet (p<0.05). In conclusion, these results indicated that chunggugjang powder would have antidiabetic and antioxidant effects in STZ-induced diabetic rats.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.10
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• pp.885-888
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• 2008

We present simulation results on DC characteristics of AlGaN/GaN HEMTs having trench shaped source/drain Ohmic electrodes. In order to reduce the contact resistance in the source and drain region of the conventional AlGaN/GaN HEMTs and thereby to increase their DC output power, we applied narrow-shaped-trench electrode schemes whose size varies from $0.5{\mu}m$ to $1{\mu}m$ to the standard AlGaN/GaN HEMT structure. As a result, we found that the drain current was increased by 13 % at the same gate bias condition and the transconductance (gm) was improved by 11 % for the proposed AlGaN/GaN HEMT, compared with those of the conventional AlGaN/GaN HEMTs.

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.6
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• pp.486-496
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• 2016

The voltage unbalance of an LVDC bipolar distribution system was controlled for high power quality. Voltage unbalance may occur in a bipolar distribution system depending on the operation of the converter and load usage. Voltage unbalance can damage sensitive load and lead to converter accidents. The conditions that may cause voltage unbalance in a bipolar distribution system are as follows. First, three-level AC/DC converters in bipolar distribution systems can lead to voltage unbalance. Second, bipolar distribution systems can be at risk for voltage unbalance because of load usage. In this paper, the output DC link of a three-level AC/DC converter was analyzed for voltage unbalance, and the bipolar voltage was controlled with algorithms. In the case of additional voltage unbalance according to load usage, the bipolar voltage was controlled using the proposed converter. The proposed converter is a dual half-bridge converter, which was improved from the secondary circuit of a dual half-bridge converter. A control algorithm for bipolar voltage control without additional converters was proposed. The balancing control of the bipolar distribution system with distributed power was verified through experiments.

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.2
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• pp.95-101
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• 2016

This paper proposed a high-power density bidirectional converter for hybrid electric vehicle high-voltage DC-DC converter(HDC). The conventional HDC has two disadvantages. First, large inductance is required to satisfy the ripple current of inductor by low switching frequency (<20 kHz). Second, large core size is required to prevent the saturation of inductor by high current. Compared with the conventional HDC, the proposed HDC can reduce inductance with SiC-FET for high frequency driving. High-power density of I/O capacitors can be achieved through two-phase interleaved method. The high-power density of inductors can be achieved because the offset current of magnetizing inductance is theoretically terminated by using the differential mode coupled inductor instead of using two single inductors. The validity of the proposed converter is proved through the 50 kW prototype.

• Journal of IKEEE
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• v.21 no.3
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• pp.260-263
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• 2017

Based on several CPU cores, an SoC including ADCs, DC-DC converter and 2M-byte SRAM is proposed in this paper. The CPU core consists of a 12-bit MENSA, a 32-bit Symmetric multi-core processor, as well as 16-bit CDSP. To eliminate the external SDRAM memory, internal 2M-byte SRAM is implemented. Because the SRAM normally occupies huge area, the parasitic components reduce the speed of SoC. In this work, the SRAM blocks are divided into small pieces to reduce the parasitic components. The proposed SoC is developed in a standard 55nm CMOS process and the speed of SoC is 200MHz.