• International Journal of Fluid Machinery and Systems
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• v.4 no.1
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• pp.57-66
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• 2011

Radial-vaned air separators show a strong stall suppression effect in an axial flow fans. From a survey of existing literature on the effects and the author's data, a possible mechanism for the significant effects has been proposed here. The stall suppression is suggested to have been achieved by a combination of the following several effects; (1) suction of blade and casing boundary layers and elimination of embryos of stall, (2) separation and straightening of reversed swirling flow from the main flow, (3) induction of the fan main flow toward the casing wall and enhancement of the outward inclination of meridional streamlines across the rotor blade row, thus keeping the Euler head increase in the decrease in fan flow rate, and (4) reinforcement of axi-symmetric structure of the main flow. These phenomena have been induced and enhanced by a stable vortex-ring encasing the blade tips and the air separator. These integrated effects appear to have caused the great stall suppression effect that would have been impossible by other types of stall prevention devices. Thus the author would like to name the device "tip-vortex-ring assisted stall suppression device".

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.10a
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• pp.94-100
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• 1997

The purpose of this study is to investigate the effects of operation factors of a typical main spindle system on its efficiency. Among important factors, material type of ball-bearing, bearing-lubricant type and main spindle bearing preload are taken into considered.

• Korean Journal of Childcare and Education
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• v.12 no.3
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• pp.197-210
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• 2016

The purpose of this study was to examine the effects of young children's stay hours on kindergartens or child care centers on their language, cognition, and social development with teacher-child interactions as a mediator. For this purpose, the data from the 2013 Panel Study on Korean Children were analyzed using the GLM and pattern analysis. The results of the GLM analysis were as follows. First, the main effects of the stay hours on child development were statistically significant Second, the main effects of the level of teacher-child interaction were also statistically significant on the results of child development. Third, the moderating effect of teacher-child interaction level between the stay hours and child development were also significant. The results showed that young children's stay hours effected their language, cognitive, and social development and teacher-child interactions mediated these effects.

• Journal of Ginseng Research
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• v.22 no.4
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• pp.289-293
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• 1998

Six-year-old ginseng roots were divided into rhizome, main root (epidermis, cortex and xylem) and lateral root (big tail root, mid tail root and fine tail root) and the concentration levels of soluble dietary fiber (SDF) and insoluble dietary fiber (IDF) in each part of the ginseng were investigated. The amount ratios of SDF to IDF (SDF/IDF) in various parts of the ginseng root were also compared. The concentration levels of SDF and IDF in the ginseng root were 6.56% and 15.41 %, respectively, where the level of SDF in main root was a little higher than that of lateral root. However the amount of IDF in main root was lower than that of lateral root. The SDF/IDF was highest in main root, 0.513, which was higher than that of lateral root or rhizome. The SDF/IDF was 0.704 in xylem, 0.478 in cortex, and 0.099 in epidermis of the main root and the SDF/IDF was 0.576 in big tail root, 0.463 in mid tail root, and 0.255 in fine tail root of the lateral root. It has been reported that SDF might have preventive effects on diabetes, obesity, high blood pressure, colon and rectum cancers, while IDF might have preventive effects on constipation. Therefore, main root of six-year- old ginseng root is thought to have a little different physiological activity from lateral or fine tail roots.

• Structural Engineering and Mechanics
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• v.58 no.6
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• pp.967-988
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• 2016

Due to the significant aerodynamic interference from sub-towers and surrounding tall buildings, the wind loads and dynamic responses on main tower of three-tower connected tall building typically change especially compared with those on the isolated single tall building. This paper addresses the wind load effects and equivalent static wind loads (ESWLs) of three-tower connected tall building based on measured synchronous surface pressures in a wind tunnel. The variations of the global shape coefficients and extremum wind loads of main tower structure with or without interference effect under different wind directions are studied, pointing out the deficiency of the traditional wind loads based on the load codes for the three-tower connected tall building. The ESWLs calculation method based on elastic restoring forces is proposed, which completely contains the quasi-static item, inertia item and the coupled effect between them. Then the wind-induced displacement and acceleration responses for main tower of three-tower connected tall building in the horizontal and torsional directions are investigated, subsequently the structural basal and floor ESWLs under different return periods, wind directions and damping ratios are studied. Finally, the action mechanism of interference effect on structural wind effects is investigated. Main conclusions can provide a sientific basis for the wind-resistant design of such three-tower connected tall building.

• YAKHAK HOEJI
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• v.51 no.5
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• pp.355-360
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• 2007

The essential oil fraction from the aerial parts of A. annua was analyzed by GC-MS. As the results, caryophyllene oxide (11.7%), caryophyllene (7.54%), camphor (7.32%), 1,8-cineol (4.98%), and borneol (3.99%) were confirmed as the main components of the oil fraction. The effects of this oil and its main components on antibiotic-susceptible and -resistant strains of Salmonella enteritidis and S. typhimurium were assessed. A. annua oil fraction significantly inhibited all strains of the two Salmonella species examined, with minimum inhibiting concentrations (MICs) ranging from 2.0 mg/ml to 8.0 mg/ml. Among the main components of the oil, borneol and camphor showed relatively strong inhibiting activity with MICs between 1.0 mg/ml and 4.0 mg/ml. The MICs of caryophyllene and caryophyllene oxide were higher than 16 mg/ml. The combination effects of the oils with kanamycin were evaluated using a checkerboard microtiter assay. Against S. typhimurium KCCM11862 and CCARM8009 strains, the oil fraction of A. annua, camphor, and 1,8-cineol exhibited significant synergistic with kanamycin with fractional inhibitory concentration (FIC) indices in the range of 0.085 to 0.375. In conclusion, a combination of kanamycin and A. annua oil or its main component, camphor, and cineol, may be useful for reducing the minimum effective dose of antibiotic required for the treatment of resistant S. typhimurium infections.

• Journal of Families and Better Life
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• v.22 no.2
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• pp.23-35
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• 2004

The purpose of this study is to evaluate child - care effects on young child's aggression in ecological context. For this, main effects, interaction effects and cumulative effects between child care experiences(quantity, quality, age of entry and stability) and maternal behavior as well as characteristics of child(sex, age and temperament) were examined. A total of 62 young children(34 boys and 28 girls) enrolled in child - care center were observed, and mothers and caregivers completed questionnaires. Data was analysed by three - way ANOVA, logistic regression and crosstabs. As result, first, main effects of quantity, rejective and regulative mothering on children's aggression were found. Second, there were significant interaction effects between both quality and quantity of day-care and rejective mothering. In particular, the interaction effects provided evidence that high - quality child - care served a compensatory function for extensive care and rejective mothering. Third, logistic regression analysis revealed risk factors for child's aggression and the effects of these risk factors were cumulative. Interaction effects of day-care quality and cumulative effects of day-care, characteristics of child and maternal behavior on child aggression were discussed.

• Journal of the Society of Naval Architects of Korea
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• v.43 no.4 s.148
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• pp.431-439
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• 2006

Due to the limitation of size of the test section, blockage effects could not be avoided in the model test of yacht sails for common wind tunnels. In this paper, a numerical analysis is performed to investigate the blockage effects on the lift and drag forces measured from wind tunnel experiments for a 30 feet sloop yacht sail. Complex airflows around the jib and main sails including three-dimensional flow separations are calculated for various close-hauled conditions. It is found that the blockage of a wind tunnel changes the flow separation and consequently the lift and drag forces of the sails, especially the main sail, reduce and increase, respectively, due to the blockage effects.

• Tribology and Lubricants
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• v.5 no.1
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• pp.69-75
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• 1989

The mobility method of dynamically loaded journal bearings was applied to optimize the lubrication of the main journal bearing of the crank press. The effects of oil viscosity, temperature bearing clearance, length, the existence of the circumferential groove, peak press force, and crank rpm were examined. From the results of the minimum film thickness and the maximum film pressure, some of the factors could be optimized, and the degrees of the beneficial and detrimental effects of the others could be estimated.

• Journal of computational fluids engineering
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• v.20 no.3
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• pp.87-93
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• 2015

In this study, a numerical analysis was performed to simulate the thermal-hydraulic response of the secondary side of a steam generator(SG) model equipped with an orifice-type SG outlet flow restrictor to a main steam line break(MSLB) at a pressurized water reactor(PWR) plant. The SG analysis model includes the SG upper steam space and the part of the main steam pipe between the SG outlet and the broken pipe end. By comparing the numerical calculation results for the present SG model to those obtained for a simple SG model having no flow restrictor, the effects of the flow restrictor on the thermal-hydraulic response of SG to the MSLB were investigated.