• Journal of Bio-Environment Control
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• v.3 no.1
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• pp.66-71
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• 1994

In order to understand the mechanism of the wide occurrence of tipburn phenomenon in Chinese cabbage grown under protected cultivation, Chinese cabbage cultivated in two experimental plots was analyzed based on the distribution of some mineral elements by region in the plant and in the soil. The following results were obtained : 1) The occurrence of tipburn is not related to the concentration of Ca in the soil. 2) The concentration of Ca by region in the plant increased in the order such as inner leaf < middle leaf < outer leaf and inner vein < middle vein < outer vein. 3) From this results the cause of occurrence of tipburn phenomenon in Chinese cabbage which occurred at fixed times in the growth and development of the plant can be controlled by modifying environmental factors in order to prevent excessive transpiration in the inner leaf.

• Macromolecular Research
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• v.8 no.6
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• pp.253-260
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• 2000

Biodegradable wafers were prepared with poly (hydroxybutyrate-co-hydroxyvalerate) (PHBV;5, 10, and 15 mole% for 3-hydroxyvalerate) by simple heat pressing method for the sustained release of antibiotic agent, gentamicin sulfate (GS) to investigate the possibility of the treatment for osteomyelitis. The effects of hydroxyvalerate (HV) content, thickness of wafers, various types of additives such as sodium dodecyl sulfate (SDS), microcrystalline cellulose, polyvinylpyrrolidone, and hydroxypropylcellulose (HPC), and different initial drug loading ratio on the release profile have been investigated. In vitro release studies showed that different release patterns and rates could be achieved by simply modifying factors in the preparation conditions. PHBV wafers with 3 mm thickness, 10% of GS initial loading, 15% of HV content and addition of 5% of SDS and HPC were free from initial burst and a near-zero-order sustained release was observed for over 30 days. It might be suggested that the mechanisms of G5 release may be more predominant simple dissolution and diffusion of GS than erosion of PHBV in our system.

• Korean Journal of Psychosomatic Medicine
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• v.16 no.2
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• pp.75-80
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• 2008

Delirium independently contributes to poor outcomes including prolonged hospital stays and increased risk of mortality. The reported prevalence of delirium in variety of medical and surgical hospital settings is from 15% to 70% ; delirium is, therefore, one of major reason for consultation that is required for psychosomatic interventions. This article reviews the psychosomatic interventions to treat delirium including 1) identification of risk factors and precipitating causes ; 2) non-pharmacological interventions, such as modifying treatment environment and educating patient's family and care-giver ; and 3) pharmacological approaches to control the various symptoms that are frequently presenting with delirium.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.05a
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• pp.186-195
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• 2001

The purpose of this study is to develop the time-dependent, one-dimensional numerical model on the interaction between irregular waves and two-layer permeable coastal structures, by extending and modifying the numerical model PBREAK(Wurjanto and Kobayashi, 1992) which is applicable only to one-layer permeable coastal structures. The two-layer permeable coastal structure consists of two permeable underlayers with different permeable media resting on an impermeable slope and an armor layer covering the permeable underlayer. The numerical model of this study simulates the wave over rough permeable underlayer of arbitrary geometry as well as the waves inside two-permeable underlayers of arbitrary thickness for specified normally-incident irregular waves. The utility of the numerical model is founded from comparing with PBREAK and the four hydraulic model tests under irregular waves. The sensitivities of computed results according to typical parameters(porosity, stone diameter, horizontal width of the permeable underlayer) and major factors(friction factor of primary armor layer etc.) discussed.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.2129-2134
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• 2004

The present study has been conducted to develop a heat pump system using river water of temperature energy which not only belongs to unutilized energy but is a kind of good heat source due to maintain its temperature in a certain degree regardless of seasonal variation. The system did not meet the proposed performance after setup. In this paper, the system performance affected by refrigerant Oil, by pressure drop, or by other factors has been discussed. The followings were obtained : (1) Refrigerant Oil mixture rate was 2.5 in weight percentage, (2) Pressure drop through evaporator was 29.1kPa($3.1^{\circ}C$ in saturated tempearture) (3) Pressure drop from the end of evaporator to compressor inlet was 39.8kPa($4.0^{\circ}C$ in saturated tempearture). (4) The system performance can to be improved by modifying a part of pipe line to compressor, and reducing pressure drop through heat exchangers.

• The Journal of Korean Association of Computer Education
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• v.18 no.2
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• pp.59-70
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• 2015

This paper aims at developing a valid evaluation tool which has reliability to measure the tendency of cyber bullying that is on the increase recently. After setting up the concept of cyber bullying and exploring its factors by reference to advanced research, we developed the draft tool through modifying by the expert group. By conducting several surveys using this evaluation tool, we have verified the reliability and validity of our tool. And we also have developed an evaluation tool to measure its tendency. As a result, the complementary evaluation tool of cyber-bullying tendency was proposed with more advanced and accurate test.

• Computers and Concrete
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• v.15 no.4
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• pp.607-642
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• 2015

The stress-strain relationship of concrete in flexure is one of the essential parameters in assessing the flexural strength and ductility of reinforced concrete (RC) columns. An overview of previous research studies revealed that the presence of strain gradient would affect the maximum concrete stress developed in flexure. However, no quantitative model was available to evaluate the strain gradient effect on concrete under flexure. Previously, the authors have conducted experimental studies to investigate the strain gradient effect on maximum concrete stress and respective strain and developed two strain-gradient-dependent factors k3 and ko for modifying the flexural concrete stress-strain curve. As a continued study, the authors herein will extend the investigation of strain gradient effects on flexural strength and ductility of RC columns to concrete strength up to 100 MPa by employing the strain-gradient-dependent concrete stress-strain curve using nonlinear moment-curvature analysis. It was evident from the results that both the flexural strength and ductility of RC columns are improved under strain gradient effect. Lastly, for practical engineering design purpose, a new equivalent rectangular concrete stress block incorporating the combined effects of strain gradient and concrete strength was proposed and validated. Design formulas and charts have also been presented for flexural strength and ductility of RC columns.

• Journal of the Korea institute for structural maintenance and inspection
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• v.5 no.4
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• pp.169-176
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• 2001

This study aims to present a more reasonable control value than the exiting one by comparing and analyzing control values and field instrument8tion values of the whole excavation depth of the four case sites, using geometric averaging as a statistical method. The range of the study is confined to the horizontal displacement of braced excavation walls among a variety of items, prescribed in the control values by approximately of the allowable and design values, and by safety factors. As a result, it is desirable to revise 70, 90, and 100 percent of LEVEL I, II, and III, respectively. The horizontal displacement values of the allowable and design values approximations should change to 104, 133, and 148 percent of the allowable and design values, respectively. In addition, modifying the horizontal displacement control value of the braced excavation walls is not needed. The horizontal displacement value, presented in the control value as a safety factor, is now 1.19, as it has a slight difference from the present value.

• Macromolecular Research
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• v.8 no.2
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• pp.80-88
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• 2000

Biodegradable microspheres were prepared with poly(L-lactide-co-glycolide) (PLGA, 75 : 25 by mole ratio) by an oil/oil solvent evaporation method for the sustained release of anti-AIDS virus agent, AZT The microspheres of relatively narrow size distribution (7.6$\pm$ 3.8 ㎛) were obtained by controlling the fabrication conditions. The shape of microspheres prepared was smooth and spherical. The efficiency of AZT loading into the PLGA microsphere was over 93% compared to that below 15% for microspheres by a conventional water/oil/water method. The effects of Preparation conditions on the morphology and in vitro AZT release pattern were investigated. in vitro release studies showed that different release pattern and release rates could be achieved by simply modifying factors in the fabrication conditions such as the type and amount of surfactant, initial amount of loaded drug, the temperature of solvent evaporation, and so on. PLCA microspheres prepared by 5% of initial drug loading, 1.0% (w/w) of surfactant concentration, and 25$\^{C}$ of solvent evaporation temperature were free from initial burst effect and a near-zero order sustained release was observed. Possible mechanisms of the near-zero order sustained release for our system have been proposed.

• Journal of Korea Multimedia Society
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• v.25 no.11
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• pp.1621-1633
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• 2022

The present study aims to design an application for anger control training of individuals and test its practical usability with the goal of encouraging preventive training in daily life. This study also investigates, through usability evaluation, whether users can use the application to carry out the actual anger management training program, whether it is useful and convenient, and whether it produces adequate learning effects. In order to conduct usability evaluation, a usability evaluation scale comprised of six factors-utility, reuse intention, learning, error, and reflectivity-was derived, and survey items tailored to each factor were produced. The association between usability evaluation elements, user demographic parameters, mobile usage behavior, and state anger was also examined. The result demonstrated that additional menus and features are necessary to increase the usability of the application for anger management. The result also revealed that it is vital to build an intuitive application interface that users unfamiliar with mobile app functionality can easily navigate, as well as to add entertaining components in the content, as users may be somewhat bored. On the basis of the findings, ideas of modifying and creating anger management training programs were discussed.