• Restorative Dentistry and Endodontics
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• v.37 no.3
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• pp.155-159
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• 2012

Objectives: To investigate the effect of dentin moisture degree and air-drying time on dentin-bond strength of two different one-step self-etching adhesive systems. Materials and Methods: Twenty-four human third molars were used for microtensile bond strength testing of G-Bond and Clearfil $S^3$ Bond. The dentin surface was either blot-dried or air-dried before applying these adhesive agents. After application of the adhesive agent, three different air drying times were evaluated: 1, 5, and 10 sec. Composite resin was build up to 4 mm thickness and light cured for 40 sec with 2 separate layers. Then the tooth was sectioned and trimmed to measure the microtensile bond strength using a universal testing machine. The measured bond strengths were analyzed with three-way ANOVA and regression analysis was done (p = 0.05). Results: All three factors, materials, dentin wetness and air drying time, showed significant effect on the microtensile bond strength. Clearfil $S^3$ Bond, dry dentin surface and 10 sec air drying time showed higher bond strength. Conclusions: Within the limitation of this experiment, air drying time after the application of the one-step self-etching adhesive agent was the most significant factor affecting the bond strength, followed by the material difference and dentin moisture before applying the adhesive agent.

• Steel and Composite Structures
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• v.20 no.4
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• pp.889-911
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• 2016

Using the hyperbolic shear deformation plate model and including plate-foundation interaction (Winkler and Pasternak model), an analytical method in order to determine the deflection and stress distributions in simply supported rectangular functionally graded plates (FGP) subjected to a sinusoidal load, a temperature and moisture fields. The present theory exactly satisfies stress boundary conditions on the top and the bottom of the plate. No transversal shear correction factors are needed because a correct representation of the transversal shearing strain is given. Materials properties of the plate (elastic, thermal and moisture expansion coefficients) are assumed to be graded in the thickness direction according to a simple power-law distribution in terms of the volume fractions of the constituents. Numerical examples are presented and discussed for verifying the accuracy of the present theory in predicting the bending response of FGM plates under sinusoidal load and a temperature field as well as moisture concentration. The effects of material properties, temperature, moisture, plate aspect ratio, side-to-thickness ratio, ratio of elastic coefficients (ceramic-metal) and three distributions for both temperature and moisture on deflections and stresses are investigated.

• Journal of the Korea Concrete Institute
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• v.18 no.1 s.91
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• pp.135-145
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• 2006

In high multistory reinforced concrete buildings, coupled shear walls can provide an efficient structural system to resist horizontal force due to wind and seismic effects. Coupled shear walls are usually built over the whole height of the building and re laid out either as a series of walls coupled by beams and/or slabs or a central core structure with openings to accommodate doors, elevators walls, windows and corridors. A number of recent studies have focused on examining the seismic response of concrete, steel, and composite coupling beams. However, since no specific equations are available for computing the bearing strength of steel coupling beam-wall connections, it is necessary to develop such strength equations. There were carried out analytical and experimental studies to develop the strength equations of steel coupling beam-connections. Experiments were conducted to determine the factors influencing the bearing strength of the steel coupling beam-wall connection. The results of the proposed equations were in good agreement with both test results and other test data from the literature. Finally, this paper provides background for design guidelines that include a design model to calculate the bearing strength of steel coupling beam-wall connections.

• Spatial Information Research
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• v.11 no.3
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• pp.241-249
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• 2003

The purpose of this paper is to provide the basic data to select the most proper site, which is essential for the economic activation of North Korea by means of the GIS tool. In this purpose, firstly, Nampo area is sampled as model case, classifying the factors into the natural environmental one and socio- cultural one. Secondly, to analyze the land use status and topographic status which is essential for natural environment factor. Besides USLE(Universal Soil Loss Equation), which is one of the disaster effect assessments, is being applied to suggest the selection method for minimizing the environment change by way of assuming the land effluence amount. The started could advance to prove the ideal model in selecting the most suitable site while minimizing the environmental change by means of the composite tool of GIS and USLE.

• Preventive Nutrition and Food Science
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• v.13 no.1
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• pp.40-44
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• 2008

Response surface methodology (RSM) was used for analyzing the manufacturing process of Prunus mume extract-added vinegared red pepper paste (maesil chokochujang) with respect to sensory quality properties. Experiments were carried out according to a central composite design, selecting the amount of kochujang, amount of maesil extract, and type of sugar in the mixture as independent variables; sensory attributes such as flavor, taste, color, and mouthfeel viscosity as response variables. The polynomial models developed by RSM for sensory color and mouthfeel viscosity were highly effective to describe the relationships between the factors studied and the responses. The estimated response surfaces confirmed that the amount of kochujang had a positive effect on color (p<0.001) whereas the amount of maesil extract had a positive effect on mouthfeel viscosity (p<0.001). Increase in the amount of kochujang led to a sharp increase of the sensory score on color at all the maesil extract and sugar type levels. On the other hand, increase in the amount of maesil extract caused a sharp increase in the mouthfeel viscosity value regardless of kochujang concentration and type of sugar. The differences among samples made with different types of sugar were not significant (p>0.05).

• Journal of the Korean Society of Clothing and Textiles
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• v.31 no.9_10
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• pp.1373-1383
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• 2007

The purpose of this study is to find out the dimensions of kidult fashion emotion and identify the influence of socio-psychological characteristics(nostalgic orientation, change inclination, and self-esteem) on kidult fashion emotion. 'Kidult', composite of kid and adult is indicating a group of people who feel nostalgic for and feel attachment to the products that they have been used in their childhood. A questionnaire was prepared in the survey and a total of 474 women in their twenties and thirties who had purchased the kidult fashion products were selected. The research findings are as follows: 1. Kidult fashion emotion can be classified as 5 factors: pursuits of fashion emotion, seeking girlish image emotion, preference for character emotion, seeking fun emotion, and past oriented emotion. 2. Socio-psychological variable that affected kidult fashion emotion is turned out change inclination. 3. The higher the seeking girlish image and pursuit of fashion emotion tendencies, the more they purchase the kidult fashion products. Based on these results, kidult fashion emotions are not the attachment to the past but positive expression of self and individuality.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.34 no.1
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• pp.14-24
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• 2011

Though many researchers have interested in the effects of creativity management on the business performance, few have researched the relationship between management execution systems for creativity management and the performance. This paper tried to identify the relationship between management execution systems for creativity management and the performance by using 181 Korean companies' survey data. In this paper, a creative management execution system is modelled by the six criteria that are widely used in the Malcolmn Baldrige National Quality Award, and the performance is measured by a composite variable called by business capability. Through an analysis of survey data using factor analysis and regression analysis, this paper tried to answer two research questions: Firstly, does creative management execution systems have the characteristics of multi-dimensionality? Secondly, does creative management execution systems have an impact on the firm's performance? It was found that a creative management execution system largely consists of two parts, which are called 'system factor' and 'management support factor', and system factors have a more strong impact on the performance. The contribution of this paper is in suggesting that establishing a systematic creative management execution system is required in order to efficiently manage for creativity.

• Journal of Microbiology and Biotechnology
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• v.20 no.4
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• pp.835-843
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• 2010

The objectives of this study were to investigate the effect of fermentation medium on the hydroxyl radical scavenging activity of exopolysaccharides from Inonotus obliquus by response surface methodology (RSM). A two-level fractional factorial design was used to evaluate the effect of different components of the medium. Corn flour, peptone, and $KH_2PO_4$ were important factors significantly affecting hydroxyl radical scavenging activity. These selected variables were subsequently optimized using path of steepest ascent (descent), a central composite design, and response surface analysis. The optimal medium composition was (% w/v): corn flour 5.30, peptone 0.32, $KH_2PO_4$ 0.26, $MgSO_4$ 0.02, and $CaCl_2$ 0.01. Under the optimal condition, the hydroxyl radical scavenging rate (49.4%) was much higher than that using either basal fermentation medium (10.2%) and single variable optimization of fermentation medium (35.5%). The main monosaccharides components of the RSM optimized polysaccharides are rhamnose, arabinose, xylose, mannose, glucose, and galactose with molar proportion at 1.45%, 3.63%, 2.17%, 15.94%, 50.00%, and 26.81%.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.8
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• pp.651-656
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• 2012

A study on capacitive characteristics of stylus pen for touch panel are progressed in this paper. Also the main factors for capacitive sensitivity are studied. Namely, highly sensitive stylus pen which can be applied to capacitive touch panel are studied based on the analysis of materials and process conditions regardless of pattern shapes. Stylus pen was made of PDMS(Poly-Di-Methyl-Siloxane) and conductive metal powders which does not damage the touch panel surface. We tried to get the advantages of both the properties of soft PDMS and conductive metal powders. We found that potential difference of capacitance change with conductivity of the composite materials(PDMS + metal powders) it implies that during touch process, large voltage difference can be caused by the high conductive materials of stylus pen. Stylus pen made by PDMS with mixed with Ag powders which has large conductivity shows more capacitance change of 1 pF than PDMS with other materials of Ni or C powders.

• Computers and Concrete
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• v.14 no.2
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• pp.109-125
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• 2014

The force transfer mechanism in positive moment continuity details for prestressed concrete girder bridges is investigated in this paper using a three-dimensional detailed finite element model. Positive moment reinforcement in the form of hairpin bars as recommended by the National Cooperative Highway Research Program Report No 519 is incorporated in the model. The cold construction joint that develops at the interface between girder ends and continuity diaphragms is also simulated via contact elements. The model is then subjected to the positive moment and corresponding shear forces that would develop over the service life of the bridge. The stress distribution in the continuity diaphragm and the axial force distribution in the hairpin bars are presented. It was found that due to the asymmetric configuration of the hairpin bars, asymmetric stress distribution develops at the continuity diaphragm, which can be exacerbated by other asymmetric factors such as skewed bridge configurations. It was also observed that when the joint is subjected to a positive moment, the tensile force is transferred from the girder end to the continuity diaphragm only through the hairpin bars due to the lack of contact between the both members at the construction joint. As a result, the stress distribution at girder ends was found to be concentrated around the hairpin bars influence area, rather than be resisted by the entire girder composite section. Finally, the results are used to develop an approach for estimating the cracking moment capacity at girder ends based on a proposed effective moment of inertia.