• Journal of the Korea Fashion and Costume Design Association
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• v.14 no.3
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• pp.11-22
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• 2012

As the consuming pattern is changing with the expansion of Internet use and the development of communication technology, Internet shopping market is getting bigger and bigger. By product group, clothing and fashion related products occupy the biggest share. Accordingly, in this study it was tried to identify the effects of Internet utilization capability that enables consumers to search for the information that they need in this information flood, variety pursuit trend and product review accommodation status on shopping value, and to analyze the effects of the shopping value on the purchase behavior in online shopping malls. When factor analysis is nude on Internet use level, it was found that Factor 1 was 'Flow Experience,' Factor 2 'Internet Use Capability,' and Factor 3 'Internet Challenge Desire.' When factor analysis is made on Diversity Pursuit Propensity, it was found that Factor 1 was 'Site Diversity Pursuit Propensity,' Factor 2 'Brand Diversity Pursuit Propensity,' and Factor 3 'Brand Value Pursuit Propensity.' When factor analysis is nude on Product Review Accommodation Propensity, it was found that Factor 1 was 'Product Information Provision Propensity,' and Factor 2 'Product Information Receiving Propensity.' Except Internet Use Capability and Product Information Provision Propensity, all other factors showed high correlation. The factor influencing the entertainment value most was Internet challenge desire, while that influencing the practical value most was flow experience. When the effects of the entertainment value and the practical value on product purchase were analyzed, it was found that both of entertainment value and the practical value influenced product purchase and the practical value influenced the product purchase more than the entertainment value.

• Science of Emotion and Sensibility
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• v.11 no.2
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• pp.257-270
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• 2008

Three experiments were carried out in order to determine whether users have longer using time, better recall of product information, and flow in an aesthetically appealing product (media player) in products offering good usability. For the experiment, fourteen emotional words were employed which were made up of 8 aesthetic and 6 usability words. In a preliminary experiment, the subjects freely used three media players and selected emotional words by a 7-point likert scale to distinguish a group of similar usability value and another group contrary to the other in aesthetic and usability value. (N=18) In the main experiment, it was hypothesized that users use more and have more flow and recalled information in the case of the aesthetically appealing product. Therefore, in the main experiment, we measured how much time subjects spent using the product and asked them to make an assumption regarding the time spent by the group that has the same usability value. We then examined the time they spent and the gap between the actual and estimated time. We also calculated the amount of menu information recalled via a questionnaire. In the last experiment, we selected the group of products contrary to each other in aesthetic and usability value and assessed the differences in using time, recall of product information, and flow. (N=18) The empirical results provide evidence that aesthetically appealing products are associated with greater flow and recall of product information than other products, thus supporting the hypothesis. In addition, it was found that there is a positive correlation between the aesthetically appealing product and flow index as well as with recalled information.

• KSTLE International Journal
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• v.7 no.2
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• pp.27-34
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• 2006

Knudsen number is the ratio of molecular mean free path versus mm thickness and the criterion to determine the flow form. When its value is lower than 0.01, the flow can be assumed to has no slip boundary condition. And in the case that the value is between 0.01 and 10, then the flow has slip boundary condition at both the adjacent walls. The condition of the air flow between the rotating journal and top foil in the air foil bearing is determined by the rotating speed and load, and the Knudsen number is also varied by those values. Because the molecular mean free path is variable to the pressure and temperature, more exact formulation is necessary to understand and analyze the flow regime. In this study, the analysis considering Knudsen number formulated with those variables (pressure, temperature and mm thickness) was executed. The approximate value was examined using the equation to confirm whether the flow has the slip or no-slip boundary condition. From the analytic investigation, it was decided to range approximately 0.01 to 1.0 and the flow can be supposed to have the slip boundary condition. Under the condition of the slip flow, the static characteristics of the air foil bearing were examined using modified Reynolds equations. The results were compared with those considering no slip condition. It shows that the slip condition makes the flow decelerates and the load carrying capacity decreases compared with no slip condition. And as the bearing number and eccentricity ratio increase, the load carrying capacity also increased at both the cases. From this result, it can be supposed that the bearing torque also increases. In the analysis of the dynamic characteristics, the perturbed Knudsen number was taken into consideration. Because the Knudsen number is expressed as the terms of each variable, the perturbed equation can be simply derived. The results of both cases considering and not considering Knudsen number were compared each other. In the case of the direct terms of the stiffness and damping coefficients, the difference between both cases was little and increased as the bearing number and eccentricity ratio increased. And the cross terms have less or more differences.

• International Journal of Highway Engineering
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• v.19 no.5
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• pp.77-88
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• 2017

PURPOSES : It is necessary to clarify the rheological properties of cement paste as a basic research in the development of mechanistic concrete mix design. The rheological properties of cement paste with different binder types, mix propositions, and with/without high range water reducers have been analyzed. METHODS : In this study, ordinary Portland cement, fly-ash, blast furnace slag, silica fume, and limestone powder were used as binders. The range of water-binder ratio was 0.3-0.5, and a total of 30 different mixes have been tested. The slump flow test, V-funnel test, and Dynamic Shear Rheometer (DSR) test were performed to analyze the rheological properties of cement paste. RESULTS : As a result of the slump flow test, it was found that the composition ratio of the binder contents greatly affected the paste flow when the high range water reducers were added. The results of V-funnel test showed that when the water-binder ratio was decreased without high range water reducers, the binder composition ratio had a large effect on the passing time of the V-funnel tester, but with high range water reducers the impact of the binder composition ratio was decreased. The slump flow and V-funnel have a certain relationship with the rheological factors (yield stress and plastic viscosity), but the correlation was not significant. Finally, we proposed the M-value considering the density and specific surface area of the binder. The correlation between rheological factors and M-value were better demonstrated than experimental values, but there is still a limit to predict the rheological factor in general mix design. CONCLUSIONS :In this study, the rheological properties of cement paste were analyzed. The binder type, composition ratio of binder, and with/without high range water reducers have combined to provide the complex effects on the rheological properties of cement paste. The correlation between the proposed M-value and rheological factor was found to be better than experimental results, but needs to be improved in the future.

• Korean Journal of Clinical Laboratory Science
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• v.36 no.1
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• pp.43-48
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• 2004

Cerebral vasoreactivity is an index of autoregulation of cerebral perfusion, and can be measured using functional images such as Xe CT, SPECT and PET in reponse to hypercapneic stimulus. In order to measure cerebral $CO_2$ vasoreactivity in routine TCD study conveniently and reliably, we devised a method of rebreathing into closed volume of reservoir bag as a hypercapneic stimulus, and applied it to 44 healthy volunteers. As a hypercapneic stimulus, we applied fitting mask connected with closed reservoir bag for about 90 seconds, and mean blood flow velocity(MBFV) and pulsatility index(PI) were evaluated at proximal middle cerebral arteries(MCA) of 50-55 mm depth, before and after the hypercapneic stimulus. Age affected the MFV and PI value showed significant and the MFV was 56.45(SD=9.75)cm/sec, while PI was 0.406(SD=0.089). As age increases the flow velocity decreased significantly whereas PI value increased(P<0.05). The vasoreactvity significantly decreased with age(P<0.05). The decrease of cerebral blood flow quantity and cerebral blood flow velocity is not only because of increase of diameter of cerebrovascular resulting from aging, but the resistance increase of small blood vessel resulting from the increase of PI & RI value is regarded. We suppose that the rebreathing method is a reliable and convenient technique as a hypercapneic stimulus in determining cerebral $CO_2$ vasoreactivity. The rebreathing method could be non-invasive and useful methods in estimation of the cerebrovascular reactivity and could be applied to the basal and follow-up evaluation of the cerebrovascular reserve of the ischemic stroke patients.

• Journal of Veterinary Clinics
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• v.37 no.4
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• pp.185-190
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• 2020

This retrospective, echocardiographic study using 144 dogs with clear systolic tricuspid regurgitation on Doppler echocardiography was performed to determine the diagnostic value of the systolic tricuspid regurgitation velocity/pulmonary artery flow velocity time integral to predict the Doppler estimates of dogs with tricuspid regurgitation pressure gradient compared with other cardiac indices of pulmonary hypertension, and to investigate a cutoff value to select patients with a potentially poor outcome. The systolic tricuspid regurgitation velocity/pulmonary artery flow velocity time integral increased significantly as the severity of pulmonary hypertension increased and had a correlation coefficient that was analogous to those of other conventional cardiac indices. A cutoff value greater 1.65 provided the best-balanced sensitivity (84%) and specificity (80%) in determining patients with a poor prognosis. In conclusion, the systolic tricuspid regurgitation velocity/pulmonary artery flow velocity time integral is readily obtained using routine echocardiography and could provide a non-invasive, novel, and supplementary index for evaluating dogs with pulmonary hypertension as useful prognostic criteria, particularly in those with advanced pulmonary hypertension.

• Journal of Korean Society on Water Environment
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• v.21 no.3
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• pp.230-235
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• 2005

The main purpose of the flocculation process is to make flocs bigger to be removed easily in the following processes. The flow pattern and mixing intensity have a great influence on flocculation. In this study, the flow pattern was examined by a hydraulic tracer-test, where 3 water treatment plants having $800,000m^3/d$, $44,000m^3/d$ and $40,000m^3/d$ were employed. Also, the settling test was conducted to find out the relationship between the mixing intensity and the settling ability of flocs. The hydraulic tracer-test was conducted for the various flocculation processes that have different structures of flocculation basins. In the result, the retention time distribution (RTD) curves for the flocculation processes were quite different. In case of the inappropriate structure of the flocculation basin, the flow is not even so that the floc does not grow enough. To find out the relationship between mixing intensity and settleability of flocs, G-values were calculated and the settling test was conducted for two flocculation basins which have the same conditions except the G-value. For the flocculation basin with uneven G-value, the floc settleability was revealed poor. On the other hand, the flocculation basin with even G-value, the settleability was better than the previous one. From these experimental results, it is confirmed that the flow pattern is closely related to the structure of the flocculation basin and the settleability is affected by mixing intensity. Therefore the flow pattern and the strength of the mixing intensity should be examined sufficiently to design and operate flocculation basin.

• Journal of Ocean Engineering and Technology
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• v.12 no.1
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• pp.153-161
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• 1998

This paper is to investigate the Fluidity of Antiwashout Underwater Concrete containing Fly Ash. The results of study are concluded as follows: the increase in Slump Flow value did not happen in the plain concrete which was replaced cement by Fly Ash; however, the maximum value could reach in the replacement of 30% of Fly Ash by weight of cement in the Fly Ash replaced concrete. On the condition of Fly Ash-Antiwashout Underwater Concrete in expecting 50 cm of the Slump Flow, it was necessary that the usage amount of Superplasticizer be around 1% of unit Binder, and 1.5% in 60 cm of the Slump Flow, respoectively.

• Journal of Surface Science and Engineering
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• v.15 no.3
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• pp.138-145
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• 1982

The effects of the simultaneous variations of the ratio of feed gases(H2/N2 Flow ratio), feed gas flow rate (H2/N2, total-flow rate) and partial pressures of TiCl4 (PTiCl41) as well as deposition time and cobalt content of the substrate on the deposition rate of the TiN Coated Cemented Tungsten Carbide Tools were investigated. Deposition was carried out in the temperature range of 930$^{\circ}C$-1080$^{\circ}C$ and an activation energy of 46.5 Kcal/mole can be calculated. Transverse rupture strength was noticeably reduced by the TiN coating on the virgin surfa-ce of Cemented Tungsten Carbide, the extent of which was decreased according to the coa-ting thickness. Microhardness value observed on the work was in the range of 1700∼2000kg/mm, which were in well agreement with the value of bult TiN. The wear resistance of TiN layers was performed by turning test and it was observed that crater and flank resistance remarkably enhanced by TiN coating.

• Journal of applied mathematics & informatics
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• v.29 no.5_6
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• pp.1081-1096
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• 2011

In this paper, a steady axisymmetric MHD flow of two dimensional incompressible fluids is studied under the influence of a uniform transverse magnetic field. The governing equations are reduced to nonlinear boundary value problem by applying the integribility conditions. Optimal Homotopy Asymptotic Method (OHAM) is applied to obtain solution of reduced fourth order nonlinear boundary value problem. For comparison, the same problem is also solved by Variational Iteration Method (VIM).