• Electronics and Telecommunications Trends
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• v.34 no.5
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• pp.71-80
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• 2019

Gallium nitride (GaN) can be used in high-voltage, high-power-density/-power, and high-speed devices owing to its characteristics of wide bandgap, high carrier concentration, and high electron mobility/saturation velocity. In this study, we investigate the technology trends for X-/Ku-band GaN RF power devices and MMIC power amplifiers, focusing on gate-length scaling, channel structure, and power density for GaN RF power devices and output power level and output power density for GaN MMIC power amplifiers. Additionally, we review the technology trends in gallium arsenide (GaAs) RF power devices and MMIC power amplifiers and analyze the technology trends in RF power devices and MMIC power amplifiers based on both GaAs and GaN. Furthermore, we discuss the current direction of national research by examining the national and international technology trends with respect to X-/Ku-band power devices and MMIC power amplifiers.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.2
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• pp.683-687
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• 2012

Ku70 plays an important role in DNA double-strand break repair. Studies revealing conflicting results on the role of the Ku70-1310C/G promoter polymorphism on cancer risk led us to perform a meta-analysis to investigate this relationship. Ten case-control studies with 2566 cases and 3058 controls were identified. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strength of associations. The overall results suggested no association between the Ku70-1310C/G promoter polymorphism and total cancer risk. However, on stratified analysis, significantly increased risks were observed among the Asian population (GG vs. CC: OR=1.50, 95%CI=1.10-2.06; GG vs. CC/CG: OR=1.47, 95%CI=1.07-2.01) and population-based case-control studies (GG vs. CC: OR=1.57, 95%CI=1.12-2.22; CG vs. CC: OR=1.35, 95%CI=1.11-1.64; CG/GG vs. CC: OR=1.37, 95%CI=1.14-1.65). Additionally, variant genotypes were associated with a significantly increased breast cancer risk (GG vs. CC: OR=1.80, 95%CI=1.26-2.56; GG vs. CC/CG: OR=1.40, 95%CI=1.01-1.95).

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.4
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• pp.13-20
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• 2008

This paper describes the design of low power 12bit Digital-to-Analog Converter(D/A Converter) using Pseudo-Segmentation method which shows the conversion rate of 80MHz and the power supply of 1.8V with 0.18um CMOS n-well 1-poly 6-metal process for advanced wireless communication system. Pseudo-segmentation method used in binary decoder consists of simple parallel buffer is employed for low power because of simpler configuration than that of thermometer decoder. Also, using deglitch circuit and swing reduced drivel reduces a switching noise. The measurement results of the proposed low power 12bit 80MHz CMOS D/A Converter shows SFDR is 66.01dBc at sampling frequency 80MHz, input frequency 1MHz and ENOB is 10.67bit. Integral nonlinearity(INL) / Differential nonlinearity(DNL) have been measured ${\pm}1.6LSB/{\pm}1.2LSB$. Glich energy is measured $49pV{\cdot}s$. Power dissipation is 46.8mW at 80MHz(Maximum sampling frequency) at a 1.8V power supply.

• Journal of the Ergonomics Society of Korea
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• v.33 no.6
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• pp.553-563
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• 2014

Objective: The purpose of this study was to evaluate the effect of gender (male, female) and grip spans (45, 50, 60, 70, 80mm) on total grip strength, resultant force, finger force and subjective discomfort rating. Background: In order to prevent musculoskeletal disorders, studies of hand tools need to be preceded based on grip strength, finger force, and subjective discomfort rating. However, experimental apparatus using tools such as pliers that reflect the actual work place was almost non-existent. Method: Fifty-Two (26 males and 26 females) participants were recruited from the student population. In this study, a pair of revised pliers, which can change grip span from 45 to 80mm was applied to estimate total grip strength, resultant force and individual finger forces. All participants were asked to exert a maximum grip force with three repetitions, and to report the subjective discomfort rating for five grip spans of pliers (45, 50, 60, 70, 80mm). Results: There were significant differences of total grip strength, resultant force, individual finger forces and subjective discomfort rating according to grip span. The lowest total grip strength was obtained from the grip span of 80mm for both genders. For resultant force, the highest resultant force was exerted at grip spans of 50, 60 and 70mm for females and 50 and 60mm for males. The lowest subjective discomfort rating was observed in the 50mm for both genders. Conclusion: Based on the result, 50mm and 60mm grip spans which provide the highest force and lowest discomfort rating might be recommendable for the male and female pliers users. Application: The findings of this study can provide guidelines on designing a hand tool to help to reduce hand-related musculoskeletal disorders and obtain better performance.

• Applied Chemistry for Engineering
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• v.9 no.6
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• pp.846-851
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• 1998

An experimental research on the preparation of zinc oxide fine particles in w/o emulsions was conducted. Precipitation solutions were zinc nitrate aqueous solutions with hexamethylenetetramine(HMTA) as precipitant. The precipitation solutions formed stable w/o emulsions with kerosine in the presence of Span 80. Homogeneous precipitation reaction occurred in the w/o emulsion after the resultant w/o emulsion was heated above the decomposition temperature of HMTA and zinc oxide particles were precipitated. In some case, zinc oxide particles of bi-modal distribution were obtained. However, zinc oxide fine particles of narrow particle size distribution could be obtained, even when the initial zinc concentration of precipitation solution and the conversion to zinc oxide are both higher that those in bulk homogeneous precipitation.

• Applied Biological Chemistry
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• v.37 no.6
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• pp.456-462
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• 1994

Lysozyme-dextran hybrids were prepared by incubated storage at $60^{\circ}C$ and 80% relative humidity for 16 days. The emulsifying properties of the hybrids were about 14 times higher than those of native lysozyme and were about 3 times higher than those of commercial emulsifiers. Lytic activity of the hybrids remained about 83% that of native lysozyme when mesured against Micrococcus lysodeikticus as a substrate. The excellent emulsifying properties of the hybrids were maintained even at pH 3 and were further improved at pH 10. The emulsifying properties of the hybrids were greatly improved by preheating the hybrids at $100^{\circ}C$. In addition the lysozyme-dextran hybrids showed an antimicrobial effect on Gram-negative bacteria.

• Korean Journal of Food Science and Technology
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• v.30 no.1
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• pp.241-243
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• 1998

The chemical composition of rice germ, a by product of rice milling, was analyzed and its oil stability was evaluated by acid value and Rancimat method during storage. The predominent components of the germ were carbohydrate (36.5%). crude lipid (21.6%) and crude protein (18.7%). The time taken to double the acid value was 2 days for common rice germ, while it took 31 days to increase 1.15 times for rice germ dried at $80^{\circ}C$ for 6 hours. Induction periods of the lipid oxidation from common or dry germ stored at different temperature were not significantly different.

• Korean Journal of Food Science and Technology
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• v.18 no.1
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• pp.1-5
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• 1986

Putrefactive microorganisms from infected onion bulbs collected at several areas were isolated and identified. The infecting microorganisms were mostly the species of Botrytis, Fusarium, Penicillium, Ericinia and Pseudomonas, among which the last was not pathogenic to onion bulbs. Fumigation of onion bulbs with Tetrachloroisophthalonitrile cut down decay rate by half of the control and the onion bulbs stored at 80% RH showed slow decay rate than those stored at 90% RH. The decay of onion bulbs was mainly caused by molds and the portions of them were 78-85% of Botrytis, 11-17% of Fusarium and 3-5% of Penicillium.

• Korean Journal of Food Science and Technology
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• v.18 no.1
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• pp.6-10
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• 1986

Fumigation of onion bulbs with Tetrachloroisophthalonitrile reduced weight loss by half of the control. The weight losses of the control onion bulbs stored at 80% RH were lower than those stored at 90% RH but no significantly different in case of fumigated onion bulbs. No rooting and sprouting to outside were detected during low temperature storage ($0^{\circ}C$) and $Q_{10}$ value of onion bulbs during storage was the range of 1.9-2.1. The weight losses of onion bulbs during storage were mainly due to decay rather than respiration, because there was positive correlation between weight loss and decay rate during storage period but not respiration ratio.

• Fashion & Textile Research Journal
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• v.8 no.1
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• pp.17-24
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• 2006

This research recognizes the importance of hotel and regular traditional restaurants contributing to tourism industry that goes along with demands of an era that considers traditional culture important, and focuses on searching for possibility by proposing direction of designs that traditional restaurant uniforms should aim. To achieve this study goal, by surveying the problems & preferences of the current uniform, over 60% of both the attendants & customers expected an improvement in the uniform. Most of the subjects wanted the improvement in design, followed by the improvement in functionality. Over 80% preferred traditional design or modernized design where traditional aspects were applied. Also, over 70% preferred a design where a pattern was applied. Among the patterns, over 80% of the subjects said that they prefer traditional patterns or modernized patterns where traditional aspects are applied. We admit that there are some limitations on this study, such as insufficient analysis & study on the attendants' action and their uniform, as well as limitations on restaurant selection. However, Through the study we expect that the Korea uniform can be differentiated from others, achieving World-class competitiveness.