• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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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.

• 한국식품영양과학회지
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• 제26권6호
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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.

• 대한토목학회논문집
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• 제28권3D호
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• pp.399-405
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• 2008

포장궤도는 기존선의 유지보수 노력을 절감하기 위하여 개발되고 있다. 이 중 베이스플레이트 저탄성패드는 궤도 전체의 지지강성을 결정하는 구성품으로서 궤도의 응력-변위특성, 동적응답, 피로특성 등에 가장 큰 영향을 미친다. 따라서 저탄성패드의 적용은 궤도전체의 내구성과 안정성에 미치는 영향이 크다고 할 수 있다. 본 논문에서는 저탄성패드의 적용으로 인하여 획득되는 효과 중 노반에 전달되는 열차하중의 저감에 대한 연구를 수행하였다. 이를 위하여 패드스프링계수별 정적해석과 실물반복재하시험을 수행하고 그 결과를 비교 분석하여 저탄성패드의 하중 전달특성을 파악하였으며 전달하중 저감효과를 검토하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집C
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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.

• 센서학회지
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• 제33권3호
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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.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2464-2472
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• 2011

열차주행이 고속화 되고 콘크리트궤도가 건설되고 있는 가운데 레일 체결장치는 저탄성화로 전달하중, 소음, 진동 등을 저감 하려는 추세이다. 따라서 저탄성패드의 적용은 궤도전체의 내구성과 안정성에 미치는 영향이 크다고 할 수 있다. 본 연구에서는 선행연구에서 다룬 패드스프링계수별 정적해석과 실물반복재하시험에 이어 동적응답해석을 추가적으로 수행하였다. 열차바퀴를 실물로 모델링하여 레일위에서 직접 주행시킴으로서 이 때 발생하는 궤도각부의 변형특성을 비교 분석하여 저탄성패드의 스프링계수에 따라 노반으로 전달되는 하중의 저감 효과를 검토하였다.

• Steel and Composite Structures
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• 제37권1호
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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.

• 센서학회지
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• 제32권2호
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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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• 제10권4호
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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.

• 한국조리학회지
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• 제22권2호
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• pp.206-221
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• 2016

스마트 폰 확산과 배달 앱의 이용 증가로 인해 배달 앱 이용 시 소비자가 지각하는 감정반응과 앱 이용의도에 관한 연구의 필요성을 제시하였다. 따라서 본 연구에서는 배달 앱에 대한 이용의도를 높일 수 있는 변수로 배달 앱의 서비스품질과 PAD의 2가지 감정차원, 각성과 즐거움을 제시하여 그 역할을 규명하고자 하였다. 이러한 분석결과를 토대로 배달 앱 콘텐츠 개발과 운영에 필요한 기초적인 자료를 제공하고자 하였다. 연구의 조사대상과 공간적 범위는 최근 3개월이내 배달 앱을 이용한 경험이 있는 전국의 20세 이상 남녀 내국인 거주자로 정하였으며, 조사대상자 중에서 배달의 민족, 요기요, 배달통을 통해 음식을 주문한 경험이 있는 외식소비자들을 대상으로 설문조사를 하였다. 연구결과, 배달 앱 서비스품질의 디자인과 공감성은 각성에 긍정적인 영향을 미치며, 디자인과 신뢰성은 즐거움에 긍정적 영향을 미치는 것으로 나타났다. 배달 앱 서비스품질의 정보성과 이동성은 앱 이용의도에 긍정적인 영향을 미치는 것으로 나타났다. PAD의 즐거움은 앱 이용의도에 긍정적인 영향을 미치나, 각성은 아무 영향력이 없는 것으로 나타났다. 외식소비자들이 배달 앱을 지속적으로 이용하도록 유도하기 위해서는 디자인과 신뢰성, 정보성, 이동성이 매우 중요한 요인임을 제시하였다.