• Journal of Korean Elementary Science Education
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• v.38 no.3
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• pp.387-394
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• 2019

The purpose of this study was to investigate the effects of writing science diary on science learning motivation, science academic achievement and ecological sensitivity of elementary students. Teaching unit was focused on 'The structure and function of plants' in 6th grade science text book. The subjects of study were 51 students of two classes. One class of 25 students, experimental group, wrote science diaries as homework. While the other class of 26 students, comparative group, performed homeworks with fill-in-the-blank worksheets. The results of this study can be summarized as follows: First, writing science diary had a meaningful effect on improvement of science learning motivation. Second, writing science diary had a meaningful effect on improvement of science academic achievement. Third, writing science diary had a meaningful effect on improvement of ecological sensitivity. And we could find that students had a favorable impression and high satisfaction level about writing science diary from the questionnaire.

• Journal of the Korean Institute of Rural Architecture
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• v.23 no.4
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• pp.63-71
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• 2021

The purpose of this study was to investigate whether the standard models for rural housing and wooden housing model have performance for hygrothermal and to propose a way of improvement relevant to hygrothermal performance for those models. All of the models to be analyzed were found to have some parts that were absent of stability in terms of performance for hygrothermal. In the process of analyzing the causes and proposing improvement measures, the following conclusions were derived. Fist, The exterior surface of the structure should be composed of a structure with good moisture permeability, and for the interior surface, a variable vapor retarder paper should be applied in consideration of the reverse condensation phenomenon in summer. Second, in terms of performance for hygrothermal, applications of external insulation plaster finish to the exterior wall or of ventilation method using a rafter vent on the roof should be avoided. Third, a rain screen method with a ventilation layer should be applied to the exterior wall, and a method of constructing ventilation layer separated from the insulation layer with a vapor retarder paper should be applied to the roof. Fourth, the application of insulation materials having capillary action, such as wood fiber insulation board or cellulose insulation board, contributes to more stable performance for hygrothermal.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.428-430
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• 2008

Dye-sensitized solar cell has many internal resistant components such as Pt counter electrode, $TiO_2$/dye/electrolyte, charge diffusion, sheet resistance of TCO. Among these, the resistance about the counter electrode can be reduced by increasing the roughness factor of Pt counter electrode. This causes the increase of fill factor and improvement of efficiency. And the amount of light reflection on the counter electrode also increases as the roughness factor goes up. In our experiment, we suggest a new deposition structure of Pt thin film that is a stepped-type structure. The more step lines are in the counter electrode, the more roughness factor is. As a result, we get the improvement of fill factor and efficiency by controlling the roughness factor of counter electrode.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.1
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• pp.61-66
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• 2004

Bleached chemithermomechanical pulp (BCTMP) was produced from CTMP of Betula maximowicziana Regel by two staged ozone-hydrogen peroxide bleaching in order to improve the optical properties of high yield pulp. This pulp was used for the evaluation of optical properties improvement, chemical characteristics of lignin in fiber and the relationship between lignin and optical properties in fiber cell wall. Hydrogen peroxide treatment improved the brightness, but the post color number (PC No.). There was little improvement on optical properties by ozone treatment, but this could be improved more by using two staged ozone-hydrogen peroxide bleaching. The hydrogen peroxide treatment did not make any change on chemical characteristics of lignin in cell wall, but by ozone treatment, it was found that the non-aromatic conjugated structure was existed in the surface of cell wall, but this could be removed by hydrogen peroxide treatment in two staged ozone-hydrogen peroxide treatment. Therefore, the optical properties was significantly improved, due to the removal of non-aromatic conjugated structure.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.148-149
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• 2014

In modern society, population overcrowding and concentration of facilities are happened because of the concentration on to city. So this phenomenon demands improvement of material's performance, technical development of structure analysis and design and improvement of constructing ability .High strength concrete has some merits. High strengthening makes the cross section reduced, and that cause decrease of structure weight. And using high durable and superplasticizer promote liquidity, thus high quality concrete can be produced. Because of these advantages, this study is for showing validity of using it by compression/tensile strength experiment. As this experiment's result, when concrete become stronger, interface intensity coefficient between cement and aggregate is different and they don't adhere to each other. So there is brittle failure. Fragility factor also steadily increase with strong concrete, it tells high strength concrete has problem. Therefore the sources used in high strength concrete like cement and aggregate must have great quality. So the source's performance must be supervised well because their quality decides performance criteria.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.10a
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• pp.134-138
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• 1995

The reinforced concrcte structure were once belicved to have permanent durability. However, it is now spoiled by durability failure caused by the corrosion of embeded steel reingorcement carbonation. alkali-aggregate reaction and salt attack Recently. salt damage has been also spreading. Salt damage is found in concrete structures built using seasands or certain admixtures containing calcium chlorides and in coastal structures frequently caught in seawater spray or blown by seawind It is the aim of this study to investigate the performance and application of new repair system for the exterior wall according to the durability improvement in the RC structures.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.1
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• pp.1-9
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• 1989

The convergence analysis of adavtive control schemes has been studied over the past decades, but the importance of structure to fast conversgece of adaptive control systems is still a controversial issue. This paper deals with the relative improvement of the exponential rate of convergence in adaptive error models. The Lyapunov's direct method is applied to adaptive control systems in order to improve the convergence rate by modifying the feedback structure of the error systems. Some simulation examples are illustrated to show fast convergence and robustness of these schemes.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.667-670
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• 2003

Ni-silicide has low thermal stabiliy. This point is obstacle to apply NiSi to devices. So In this paper, we have studied for obtain thermal stability and analysis of dopant dependency of NiSi. And then we applied Ni-silicide to devices. To improvement of thermal stability, we deposit Ni70/Co10/Ni30/TiN100 to sample. Co midlayer is enhanced thermal stability of NiSi. Co/Ni/TiN, this structure show very difference between n-poly and p-poly in sheet resistance. But Ni/Co/Ni/TiN, structure show less difference. Also junction leakage is good.

• Journal of the Korean Society of Safety
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• v.28 no.4
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• pp.97-102
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• 2013

This paper presents a new strengthening method of underground box structures against seismic loads for anti-seismic capacity improvement. A threaded steel member with pressure devices(so called 'I-bracing pressure system') is used to improve seismic capacity of the RC box structure. The I-bracing pressure system is fixed the corner of opening after chemical anchor was installed by drilling hole on the box structure. The structural performance was evaluated analytically. Two bracing types of strengthening methods were used; conventional bracing method and improved I-bracing pressure system. For the performance evaluation, seismic analyses were performed on moment and shear resisting structures with and without I-bracing pressure system. Numerical results confirmed that the proposed I-bracing pressure system can enhance the seismic capacity of the underground RC box structures.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1176-1180
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• 2008

This paper represents a study on design hypothesis to improve properties of a product. The functional requirements and function structure of various technical products are analysed. From the above analysis we could formulate one hypothesis. This hypothesis also satisfies basic rules clarity, simplicity and safety that are required in all design cases. The hypothesis says that functional requirements is refined to improve and if there are components which have the same function, they can be integrated into one component and improved. A one-handed faucet was developed by applying the above hypothesis to a two-handed faucet. The design of heat exchange tester was be improved successfully through the hypothesis.