• YAKHAK HOEJI
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• v.52 no.3
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• pp.225-231
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• 2008

To clarify effects of the structural changes of Fur protein on the resistance to metronidazole (Mtz), the mutational analysis of structure and function of the protein in Helicobacter pylori (Hp) was undertaken. It was identified that some changes in Hp Fur protein resulted in increase of resistance to Mtz, and other changes resulted in decrease of resistance. Increase of Mtz resistance came from the enzyme's decreased ability of reducing prodrug Mtz to the form of bactericidal agent. Some sites that affects Mtz resistance (i) in Fur's N terminal extension, and (ii) in its central region, which links DNA binding and Fe-binding modules were identified. It was also found that the addition of FLAG tag to Fur's C terminus also significantly impairs Fur function.

• Journal of the Korean Institute of Landscape Architecture
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• v.35 no.3
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• pp.105-113
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• 2007

This study was conducted to analyze the effects of environmental factors such as soil moisture, light intensity, temperature and humidity on changes in cambial electrical resistance. To improve data quality, cambial electrical resistance was continuously measured at fixed points by using a data logger isolated from alternating current. The relationship between environmental factors and changes in cambial electrical resistance was also analyzed. The results are as follows: 1. Cambial electrical resistance is highly correlated to the temperature of the measured area(r=-0.934). Therefore, temperature compensation is needed to analyze the effects of other environmental factors on cambial electrical resistance changes. 2. If temperature is compensated for, the change of cambial electrical resistance is highly correlated to water vapor pressure(r=-0.836). 3. If temperature and humidity are compensated for, the change of cambial electrical resistance is highly correlated to intensity of light(r=-0.738). 4. Diurnal deviation of soil water potential is not more significantly related than the change of cambial electrical resistance. However, in the long-term, soil water potential and cambial electrical resistance are highly correlated(r=-0.831). This indicates that soil moisture significantly influences the long-term change of cambial electrical resistance.

• Korean Journal of Weed Science
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• v.4 no.1
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• pp.96-106
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• 1984

Changes in weed floras and development of plant resistance to herbicides seemed to be closely related with increased and repeated use of herbicides. Herbicide use increased from 5% of the total consumption of pesticide in 1950 to 45% in 1976 in world basis. About 200 herbicides have been introduced to agriculture so as to control about 206 weed species which have been recorded important to human beings. In Korea, there was about 351 times in increased use of herbicides from 1966 to 1982. Interspecific selection by herbicide is mainly responsible for changes in weed floras and resulted in varying tolerance or susceptibility to herbicides, together with the changes of agricultural practices. The present trend toward continuous cereal cultivation throughout world will lead to type of changes in weed floras favorable to therophyte which can survive under unfavorable conditions as seeds rather than the types of geophyte which can survive unfavorable seasons as buds placed below soil surface. However, geophyte such as Sagitaria pygmaea, and Scirpus jurtcoides, and Cyperus rotundus and Cynodon dactylon in temperate warm climate become severe paddy weeds, presumably because of the removal of annual weeds by herbicides. Since differential tolerance to 2,4-D was firstly reported in Agrostis stolofera, about 30 species of weeds in 18 genera are presently known to have developed resistance to triazine herbicides. Resistance of weed biotypes to triazine herbicide is not mainly due to limited absorption and translocation or to the difference in metabolism, but is the result of biochemical changes at the site of metabolic activity, such as a loss of herbicide affinity for triazine binding site in the photosystem II complex of the chloroplast membrane. Genetical study showed that plastid resistance to triazine was wholly inherited through cytoplasmic DNA in the case of Brassica campestris. Plant tissue culture method can be utilized as an alternate mean of herbicide screening and development of resistance variants to herbicides as suggested by Chaleff and Parsons. In this purpose, one should be certain that the primary target process is operational in cell culture. Further, there are a variety of obstacles in doing this type of research, particularly development of resistance source and it's regeneration because cultured cells and whole plants represent different developmental state.

• Journal of Magnetics
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• v.17 no.4
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• pp.280-284
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• 2012

This paper presents a method for evaluating interior permanent magnet synchronous motor (IPMSM) performance over the entire operation region. Using a d-q axis equivalent circuit model consisting of motor parameters such as the permanent magnetic flux, copper resistance, core loss resistance, and d-q axis inductance, a conventional mathematical model of an IPMSM has been developed. It is well understood that in IPMSMs, magnetic operating conditions cause cross saturation and that the iron loss resistance - upon which core losses depend - changes according to the motor speed; for the sake of convenience, however, d-q axis machine models usually neglect the influence of magnetic cross saturation and assume that the iron loss resistance is constant. This paper proposes an analysis method based on considering a magnetic cross saturation and estimating a core loss resistance that changes with the operating conditions and speed. The proposed method is then verified by means of a comparison between the computed and the experimental results.

• Journal of Information Technology Applications and Management
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• v.10 no.1
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• pp.47-59
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• 2003

This study analyses the level of resistance which workers have against the adoption of ERP systems and the factors affecting the resistance to the adoption of the new systems. The major results of the study include 1) about 40% of workers showed resistance to the adoption of ERP systems, and 2) all six factors (technical characteristics of ERP system, functional characteristics of ERP system, implementation approach, task changes caused by the adoption of ERP system, attitude toward change, and altitude toward organization) were proved to affect the resistance to the adoption of the ERP systems. In practice, adoption of ERP system brings significant changes to workers. In order for an organization to succeed, it is necessary to reduce the resistance of workers. Since this study is performed based on a case study, the results of the study may not be generalized. However, the results of the study may provide guidance which organizations can refer in the course of effective personnel management.

• Journal of Technologic Dentistry
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• v.30 no.2
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• pp.9-16
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• 2008

The surface microstructural changes, mechanical properties and corrosion resistance of Ti-Pd alloys for dental biomaterials have been investigated. Ti, Ti-Pd alloys were melted in arc furnace and the corrosion resistance of Ti-Pd alloys was evaluated by anodic polarization test. The surface microstructural changes and mechanical properties of Ti-Pd alloys were analysed by scanning electron microscope and Vickers micro-hardness tester. The vickers hardnees of pure Ti improved by addition of Pd but Ti-25Pd alloy showed decreasing compared with Ti-15Pd. And anodic polarization and potentiostatic test were conducted in 5% HCl to quantify the resistance to corrosion with the addition of Pd, There was no significant difference in corrosion resistance between pure Ti, Ti-5Pd and Ti-15Pd alloy. However, Ti-25Pd alloy showed decreasing compared with pure Ti in corrosion resistance. From these results, it was concluded that newly formulated Ti-15Pd experimental alloy have adequate hardness and high corrosion resistance, and this alloy is promising candidate for a successful dental casting alloy.

• Journal of Ship and Ocean Technology
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• v.10 no.1
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• pp.1-9
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• 2006

The resistance reduction by an air lubrication effect of a large air cavity covering the hull bottom surface and the similarity relations involved have been investigated with a series of towing tank tests of three geometrically similar models. The test results of geometrically similar models have indicated that a large air cavity was formed beneath the bottom having a backward-facing step by artificially supplying air is effective for resistance reduction. The areas of air cavity and the required flow rates of air are directly related to the effective wetted surface area. The traditional extrapolation methods seem to be applicable to the estimation of the resistance in the tested range if corrections are made to account the changes in the frictional resistance caused by the changes in the effective wetted surface area. To investigate the effectiveness of air lubrication in improving the resistance performance of a practical ship, a small test boat having a backward-facing step under its bottom has been manufactured and speed trials in a river have been performed. Air has been supplied artificially into the downstream region of the bottom step to form a large air cavity covering the bottom surface. The results have confirmed the practical applicability of air lubrication for the resistance reduction of a small high-speed boat.

• Journal of IKEEE
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• v.27 no.1
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• pp.85-92
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• 2023

Recently, as the era of the 4th Industrial Revolution approaches, IoT devices that emphasize portability are increasing. At the same time, battery usage is also increasing rapidly. With the rapid increase in battery usage, issues related to battery safety have become inevitable problems and many studies have been conducted. This paper deals with explosion issues caused by swelling among various battery issues, and includes research and development of a system that detects battery swelling by identifying resistance changes. The core technology of this study is to develop a system that frequently detects changes in the resistance of wires drawn on the battery through changes in volume that occur when the battery swelling, and uses the resistance changes to prevent battery explosion. In addition, through pattern analysis, it was analyzed how the wire should be constructed to cause a lot of resistance changes.

• Journal of the Society of Naval Architects of Korea
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• v.41 no.6
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• pp.33-39
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• 2004

The performance of a deep water drillship, is investigated with the view of the characteristics of the thrusters and the resistance increasement due to moonpooi. The model tests have been performed to obtain the resistance of two drillships with the moonpooi open and closed including shape changes of moonpool step. To design the DP system, thrust forces of azimuth thrusters have been measured during azimuthing at zero speed condition. Thrusters, azimuthing under the bottom of ship, have the interactions of the other thrusters due to flow changes made by other thrusters, and the existence of ship hull makes the thrust deduction higher than when the thrust operates by itself. The resistance increasement due to the moonpooi is highly dependent on the step height of the moonpool and the draft. It is found that the height of moonpool step can reduce the resistance increasement by moonpool.

• Elastomers and Composites
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• v.52 no.1
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• pp.1-8
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• 2017

Hydrolysis resistance and mechanical property changes of polyketone (POK)/glass fiber (GF) composites were investigated for GF concentrations varying between 30 and 50%. The hydrolysis resistance of GF filled POK and polyamide66 (PA66, hydrolysis resistant grade) composites were compared. As shown by the experimental results, increasing the immersion time of the composites in a monoethylene glycol (MEG)/water solution at $120^{\circ}C$ had no impact or resulted in slightly decreased mechanical properties such as the tensile strength, tensile modulus, and strain at break in case of POK composites, whereas the mechanical properties of PA66 composites showed a significant drop. Increasing GF concentrations increased the tensile strength, tensile modulus, flexural strength, and flexural modulus of POK composites; however, impact strength did not show significant changes. Hydrolysis mechanisms of POK and PA66 are discussed.