• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.6
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• pp.702-708
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• 2019

The range resolution of echo sounders can be improved by enhancing the transducer bandwidth. We designed a bandpass matching network for expanding the bandwidth of a transducer by scaling in both impedance and frequency after transforming a lowpass network into a bandpass configuration for a third-order Bessel filter. We measured the effect of the Bessel matching network for a 50 kHz sandwich type transducer on the transmitting voltage response (TVR), receiving sensitivity (SRT) and figure of merit (FOM), using a chirp echo sounder system. Both the simulation and experimental results indicated that the transducer with a bandpass matching network was capable of producing a symmetrical acoustic output over a wider bandwidth (8.25 kHz) than was the transducer without a matching network (3.75 kHz). By implementing the Bessel matching network, we achieved a 120% bandwidth enhancement.

• Archives of Plastic Surgery
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• v.44 no.6
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• pp.559-563
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• 2017

Supported by recent literature on the signs of aging of the middle and lower face, our clinical research has documented a loss of volume of the deep structural components of the central face and a progressive descent of the nasolabial fat and the jowl fat, leading to facial fragmentation. The signs that appear around the age of 45 to 50 years are well targeted by the mini-invasive technique described here. We focused on refitting the jowl fat and the nasolabial fat associated with cutaneous tightening. The use of absorbable barbed sutures (Quill) led to significant improvements, enabling the fitting of fat on fat. In the past 4 years, 167 operations were performed using this technique. The clinical results were very satisfactory, yielding a natural effect caused by the mobilization and strong fixation of the nasolabial fat and the jowl fat in the direction opposite to their displacement.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1995.04a
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• pp.45-46
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• 1995

Alzheimer's disease is believed to be associated with the loss of cholinergic activity in the cortex and hippocampus. In addition, it has been reported that the monoaminergic systems which also controls brain functions are disturbed in Alzheimer's patients. Based on these neurochemical background, a number of cholinesterase inhibitors including tacrine and its analogues and some monoamine oxidase inhibitors such as L-deprenyl and monoamine reuptake inhibitors have been developed for the treatment of dementia, but all of the known drugs are not truly effective. We thought that a drug that activates only one neurotransmitter system is not effective enough for the treatment of the symptoms associated with Alzheimer's disease and vascular dementia, and we conceived that an agent enhancing both central cholinergic and monoaminergic functions would be useful for the treatment of dementia

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.05a
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• pp.416-417
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• 2000

Chitin, a poly $\beta$-(1longrightarrow14)-N-acetyl-D-glucosamine, is best known as a cell wall component of fungi and as a skeletal materials of invertebrates. Chitosan is derived from chitin by deacetylation in the presence of alkali. Chitosan has been developed as new physiological materials since it possesses antibacterial activity, hypocholesterolemic activity and antihypertensive action. However, the actions of chitosan in vivo still remain ambiguous as the physiological functional properties because most animal intestines, especially the human gastrointestinal tract, do not possess enzyme such as chitosanase which directly degrade the $\beta$-glucosidic linkage in chitosan, and consequently the unbroken polymers may be poorly absorbed into the human intestine. Therefore, recent studies as chitosan have attracted interest for chitosan oligosaccharides, because the oligosaccharides process not only water-soluble property but also versatile functional properties such as antitumor activity, immune-enhancing effects, enhancement of protective effects against infection with some pathogens in mice and antimicrobial activity (Kingsnorth et al., 1983, Mori et al., 1997). (omitted)

• Journal of The Korean Society of Grassland and Forage Science
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• v.21 no.2
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• pp.45-48
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• 2001

In an effort to optimize tissue culture responses of tall fescue, the effects of basic medium and carbon sources on seed culturability and genotypic difference of plant regenerability were investigated. The MS basal medium was superior to $N_{5}$ 6/ and $B_{medium}$ in enhancing callus growth and plant regeneration. To determine the effect of carbon sources on plant regeneration, the seeds were cultured on medium with 30 g/L sucrose and maltose, respectively. Medium supplemented with 30 g/L sucrose resulted in regeneration of shoots from 50% of the calli. The genotypic difference in plant regenerability was obvious among five cultivars of tall fescue tested. \\`KY31\\` and \\`Hokuryo\\` showed to have higher regenerability with the frequency of 33% and 51%, respectively.

• Health Policy and Management
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• v.13 no.4
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• pp.66-83
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• 2003

Self-efficacy is a person's perceived capability to perform a behavior. We have studied the antecedents of self­efficacy, and its moderating role on the relationship between job characteristics and job satisfaction. Data is collected through questionnaire from 910 employees of 6 large hospitals in Korea. The results show that individual's internal locus of control has positive relationship with self­efficacy and self-efficacy has positive relationship with job satisfaction. Contrary to the hypothesis, supervisors' transformational leadership doesn't show any relations with self­efficacy. The moderating role of self efficacy on the relationship between job characteristics and job satisfaction is supported. These results suggest that hospital managers should manage the self­efficacy as an important instrument of enhancing productivity and employee satisfaction.

• Journal of Food Hygiene and Safety
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• v.11 no.1
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• pp.31-34
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• 1996

Aloe, being used widely as a health food and also as a traditional folk remedy for burns and constipation, contains quinone derivatives particularly in its skin. Thus, we have investigated the effect of extracts of Aloe in ethanol metabolism. The dried powder of water extract of skinned Aloe (300 mg/kg body weight given to rats by oral adminstration at 30 min prior to oral adminstration of ethanol given at a does of 4 gm/kg) and the freeze-dried Aloe gel commercial product (600 mg/kg) which was prepared after selective elimination of quinones were found not to increase the ethanol metabolism rate in vivo. This result suggested that quinones, missing from the above preparations, might be responsible for enhancing ethanol metabolism rate.

• Journal of Information Technology Applications and Management
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• v.14 no.4
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• pp.75-96
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• 2007

The effects of information quality and the importance of information have been reported in the Information Systems (IS) literature. However, little has been learned about the impact of information visualization types and contextual information on decision quality. Therefore, this study investigated the interaction effects of these variables on decision quality by conducting a laboratory experiment. Based on two types of information visualization and the availableness of contextual information, this study had a $2{\times}2$ factorial design. The dependent variables used to measure the outcomes of decision quality were decision accuracy and time. The results demonstrated that the effects of contextual information on decision quality were significant. In addition, there was a significant main effect of information visualization on decision accuracy. The findings suggest that decision makers can expect to improve their decision quality by enhancing information visualization types and contextual information. This research may extend a body of research examining the effects of factors that can be tied to human decision-making performance.

• Journal of Electrochemical Science and Technology
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• v.7 no.3
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• pp.199-205
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• 2016

We present the electrochemical performance of electric double layer capacitors (EDLCs) assembled with pyrrolidinium (Pyr)-based ionic liquid electrolytes at 55 ℃. Cations with various alkyl chain lengths were employed in Pyr-based ionic liquids to investigate the effect of cation structure on the cycling stability of EDLCs. The EDLCs exhibited initial specific capacitances ranging from 122.4 to 131.6 F g⁻¹ based on activated carbon material at 55 ℃. Cycling data and XPS results demonstrate that Pyr-based ionic liquid with longer alkyl chain is more effective for enhancing the cycling stability of EDLC by suppressing the reductive decomposition of pyrrolidinium cations during cycling at high temperatures.

• Journal of the Korea Society of Computer and Information
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• v.20 no.12
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• pp.175-180
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• 2015

It is important to maintain information system (IS) following the business and institutional change. Even if successfully developed information systems, we cannot gain the benefit from the systems without the proactive maintenance activities. However, the importance of IS maintenance has not been considered as much as the system development, and we don't have any specific performance management structure. The objective of this study is to identify the relationship between IS maintenance activities and utilization. For empirical test of the hypothesis model, the sample data is collected from public information system sites. Results from multiple regression analysis reveal that proactive maintenance activities including IS maintenance cost increase, improving functionality, and enhancing ease of use have a causal effect on the IS utilization.