• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1230-1235
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• 2011

The track stiffness is determined by the pad stiffness. Low elastic pad is the most effective track component on the basis of stress-displacement characteristics, dynamic response and fatigue characteristics. It is more important in case of concrete track. The main objective of this paper is to confirm the reduction effect of train load, which transfer to roadbed through track. To achieve this object, numerical analysis and real scale repeated loading test was performed. The load reduction effect of low elastic pad was analyzed by using displacement, stress and strain ratio of the paved track at each point.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.6
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• pp.1200-1207
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• 1997

Effects of kimchi on lipid metabolism and immune function were studied in experiments using 63mals SD rats fed 6 inds of Baechu-kimchi containing diet during 4 weeks. Three kinds of freeze dried kimchi differ in fermentation period (not fermented, 3-, 6-week-fermented at 4$^{\circ}C$) were added at 5%, 10% of the diet containing 15% lard. The levels of serum total lipid and triglyceride and the content of liver total lipid and triglyceride of all kimchi groups were lower than those of a control group. But the levels of serum and liver cholesterol is not affected by kimchi intake. The triglyceride concentration of epididymal fat pad and feces of kimchi groups were higher than those of a control group. The food efficiency ratio, epididymal fat pad weight of 3-, 6-week-fermented kimchi 10% groups were significantly lower than control and not-fermented kimchi groups. Especially 6-week-fermented kimchi groups showed adipocytes, less in number and larger in size than those of other groups. The blastogenesis of spleen lymphocytes to LPS was higher in rats fed fermented kimchi diets than rats fed control and not-fermented kimchi diet. These results suggest that kimchi stimulates lipid mobilization to epididymal fat pad and lipid excretion via feces, so lower serum and liver triglyceride concentration. The fermented kimchi stimulate the proliferation of B cell and lower the lipid accumulation in epididymal fat pad, especially kimchi fermented for 6 weeks at 4$^{\circ}C$ lower the adipose cell number.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3D
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• pp.399-405
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• 2008

Development of the paved track is required as a low-maintenance of conventional line. The paved tracks are one of the types of the ballast reinforced tracks those are manufactured by adopting the prepacked concrete technique. The main elements of this tracks are large sleeper, low elastic pad, fastener, cement mortar, geotextile and recycled ballast. Low elastic pad is the most effective element of such tracks on the basis of stress-displacement characteristics, dynamic response and fatigue characteristics. The stiffness of the pad determine the stiffness of the track. Consequently, it is more important in case of concrete track structure such as paved track because application of low elastic pad seriously effect the durability and stability of the track. The main objective of this study is to confirm the reduction of train load, which transfer to roadbed through various pad effects. To achieve this task static, numerical analysis and real scale repeated loading test was performed while load reduction effect of low elastic pad was analyzed by using displacement, stress and strain ratio characteristics of the paved track.

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.281-286
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• 2001

Tilting pad journal bearings have been widely used in a high speed rotating machinery, such as steam turbines and gas turbines, owing to their inherent stability characteristics. However, some peculiar fatigue failure in the babbitt metal due to spragging has been continuously occurred at the leading edge of the upper pads. The spragging is defined as the pad vibration initiated on the upper unloaded pads in a tilting pad journal bearing. This paper describes both several kinds of bearing failure related with spragging and the theoretical investigation on the prevention of the spragging phenomenon using the variation of preload. Results show that positive preload(m>0.5) assures all pads remain statically loaded under all operating conditions. For the change of design parameter to prevent spragging, thermo-hydrodynamic lubrication and rotor dynamic analysis were performed to verify temperature limitation on bearing and vibration problems on rotor bearing system.

• Journal of Sensor Science and Technology
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• v.33 no.3
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• pp.158-164
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• 2024

We developed a self-operated paper pump that can maintain a nearly constant flow rate of an aqueous solution along a paper strip channel in paper-based analytical devices (PADs). The quasi-stationary flow rate was controlled by increasing the crosssectional channel area (capillary force) using a fan-shaped absorption pad coupled with a paper strip channel. The flow rate is regulated by varying the fan angle of the circular absorbing pad. Furthermore, the flow rate can be increased by furnishing a hollow cavity at the center of a conventional paper strip channel. The rate was regulated by varying the length of the hollow paper channel in the flow rate range of 5.1-26.4 mm/min. As a preliminary work, a paper-pump-coupled PAD was fabricated, and its CV detection capability was evaluated for the redox reaction of Fe(CN)₆^+4/+3. The combination of a paper pump with a PAD resulted in an ideal CV curve with a higher limiting current and faster response time. These results are interpreted well by the Levich equation, which suggests that the paper pump is a very useful component in paper-based sensors.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2464-2472
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• 2011

Train runs on high speed and the concrete track is constructed. Rail fastening device needs to reduce elasticity, transferred load, noise, and vibration etc. Consequently, low elastic pad has a great impact of the durability and stability of the track. In this study, discussed in previous studies, static numerical analysis and real scale repeated loading test, followed by dynamic response analysis were implemented. The most distinctive characteristics of the model proposed is to simulate the real wheel behavior on rail. And the main analysis object is to evaluate and compare the deformation characteristics of the transition track while load reduction effect of transfer on roadbed assessed by various low elastic pad.

• Steel and Composite Structures
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• v.37 no.1
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• pp.99-115
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• 2020

This article deals with the dynamic analysis in pad concrete foundation containing Silica nanoparticles (SiO₂) subject to seismic load. In order to control the foundation smartly, a piezoelectric layer covered the foundation. The weight of the building by a column on the foundation is assumed with an external force in the middle of the structure. The foundation is located in soil medium which is modeled by spring elements. The Mori-Tanaka law is utilized for calculating the equivalent mechanical characteristics of the concrete foundation. The Kevin-Voigt model is adopted to take into account the structural damping. The concrete structure is modeled by a thick plate and the governing equations are deduced using Hamilton's principle under the assumption of higher-order shear deformation theory (HSDT). The differential quadrature method (DQM) and the Newmark method are applied to obtain the seismic response. The effects of the applied voltage to the smart layer, agglomeration and volume percent of SiO₂ nanoparticles, damping of the structure, geometrical parameters and soil medium of the structure are assessed on the dynamic response. It has been demonstrated by the numerical results that by applying a negative voltage, the dynamic deflection is reduced significantly. Moreover, silica nanoparticles reduce the dynamic deflection of the concrete foundation.

• Journal of Sensor Science and Technology
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• v.32 no.2
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• pp.67-74
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• 2023

A microfluidic paper-based analytical device (µPAD) is proposed for the selective detection of ammonia in water by using the modified Berthelot reagent and a fluidic channel consisting of hollow paper. The modified Berthelot reagents were uniformly dispersed in cyclohexane and then immobilized in a detection zone of the µPAD. The loading position of the reagents and the type of a sample flow channel were optimized to achieve a sensitive ammonia detection within a short analytical time. The NH₃ µPAD exhibits a linear colorimetric response to the concentration of ammonia dissolved in water in the range of 1-100 mg L^-1, and its limit-of-detection is 1.75 mg L^-1. In addition, the colorimetric response was not influenced by the addition of 100 mg L^-1 nitrogen containing compounds (sodium nitrate, sodium nitrite, uric acid, hydroxylamine, butylamine, diethylamine) or inorganic salts (NaCl, Na₂HPO₄), presenting the enough selectivity in the detection of water-dissolved ammonia against possible interferents.

• International journal of advanced smart convergence
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• v.10 no.4
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• pp.183-197
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• 2021

Xiaohongshu is called China's Instagram and is leading overseas product purchases and culture sharing. The purpose of this study is to investigate the structural relationship between Xiaohongshu service quality, emotional response perceived by users, and adhesion to confirm the impact on Xiaohongshu's adhesion at a time when non-face-to-face activities due to COVID-19 have increased. This study distributed and collected questionnaires from October 1st to October 7th, 2021, targeting 210 online shopping mall users. The research results were derived from a total of 206 questionnaires, excluding 4 questionnaires such as omission of record contents, and the causal relationship of the existing PAD model was attempted to be reported by revising and supplementing the existing PAD model. As a result of the study, first, it was confirmed that design among service quality had a positive effect only on ventilation during the user's emotional response. Second, it was confirmed that information among service quality had a positive effect on pleasure and ventilation among users' emotional responses. Third, it was found that security among service quality had a positive effect on pleasure among users' emotional responses. Finally, it was found that pleasure and ventilation had a positive effect on adhesion in the user's emotional response. Based on this result, it is expected that it will be used for operation on other online platforms than the plan for the development of Xiaohongshu.

• Culinary science and hospitality research
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• v.22 no.2
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• pp.206-221
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• 2016

This study presented the need to research into 'emotional response' and 'willingness to use apps', perceived by consumers using food delivery apps amidst the spread of smartphones and surge in use of food delivery apps. This study was also intended to present 'service quality' of food delivery apps, along with 'arousal' and 'pleasure' which represented the 2 types of emotional dimension of Pleasure-Arousal-Dominance(PAD), as variables that could strengthen the willingness to use food delivery apps and examine their roles. On the basis of results of such analysis, we intended to provide basic data necessary for development and operation of food delivery app contents. For subjects and spatial scope of this study, we selected domestic male and female residents nationwide who were aged 20 or older and had experience of using food delivery apps over the last 3 months. Among the subjects of this study, we surveyed foodservice consumers who had experienced of ordering food via food delivery apps such as Baedal Minjok, Yogiyo, and Baedaltong. Based on results of this study, it was found that design and sympathy related to food delivery app service quality had a positive effect on arousal while design and reliability had a positive effect on pleasure. Both informativity and mobility of food delivery app service quality were found to have a positive effect on the willingness to use apps. The pleasure from PAD had a positive effect on willingness to use apps, while arousal did not have any effect on willingness to use apps. The results of this study suggested that design and reliability, informativity, mobility were very important factors in inducing foodservice consumers to use food delivery apps continuously.