• Journal of Korean Elementary Science Education
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• v.38 no.3
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• pp.317-330
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• 2019

The purpose of this study is to investigate the influences of science leading schools on primary and middle school students' positive experiences about science (PES) through in-depth interviews with teachers in charge of science leading schools. Science leading schools at the primary and middle school level such as Creative Convergent Science Labs and Student Participatory Science Classes were investigated and 11 teachers were participated in focus group interviews. Teacher in-depth interviews were conducted to explore the factors that led to the effectiveness of science leading schools in improving the student's PES in light of operational characteristics of science leading schools, characteristic factors of science leading schools on students PES, and improvement plans and requirements of science leading schools, as well as implications for general high schools. Science leading schools including Creative Convergent Science Labs and Student Participatory Science Classes applied for the leading school funding to secure supplies, equipments, and lab improvement for authentic science classes. In addition, reconstructed the curriculum more broadly than before, and emphasized and expanded student participatory classes and process-centered assessment at the teacher learning community level. Through student-participatory classes, the science leading schools stimulate students' interest in science, provide students with PES) through various instructions including projects, engage students in interesting science experiences in Creative Convergent Science Labs, and enhance inquiry skills and PES as well as science content knowledge. Based on the results, ways to spread the characteristics of science leading schools to general schools are suggested including expanding budget support, securing the space of science labs and improving spatial composition, providing diverse teaching and learning materials, diversifying assessment subjects and methods, and the necessity of teachers' continuous professional development, etc.

• 한국정보교육학회:학술대회논문집
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• 2021.08a
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• pp.113-121
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• 2021

This study was intended to present an online survey and analysis of the survey results after the operation of the AI education leading school initiation workshop consulting training and the creative convergence type information education room consulting training. Through this, it was confirmed that there is a perception that support such as AI education leading school consulting training is necessary, and the network should be activated to share best practices and an efficient and flexible operating system in terms of operation of leading schools nationwide. could In addition, while the subjects of the survey recognized the importance of AI education-related competency, it was identified that they had low awareness of their AI education-related competency, and recognized the need for various support for systematic and customized AI education-related competency reinforcement.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.823-827
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• 2008

The effects of blade leading edge sweep on both the aerodynamic performance and the structure stress of a high pressure centrifugal compressor impeller are numerically investigated. Changes in the flow structure occur as a result of the effect of leading edge sweep on the loading distribution in the tip region. The flow separation is avoided by introducing a sweep of the main blade leading edge and the strength of shock is reduced at the same time. Backswept of the leading edge is found to be beneficial to the impeller performance improving. On the other hand, the structural analysis indicated that high rotating speed of the impeller will cause substantial high bending stresses and radial deflections of the blade. Studies have shown that it is possible to control the stress distribution along the tip and root of the blade by slight adjustments to the sweep angle of the leading edge. These adjustments may be used to design the impeller with lower blade root stress distribution without aerodynamics performance penalty.

• Journal of Mechanical Science and Technology
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• v.18 no.12
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• pp.2273-2283
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• 2004

The vortical flows over sharp-edged delta wings with and without a leading edge extension have been investigated using a computational method. Three-dimensional compressible Reynolds-averaged Navier-Stokes equations are solved to provide an understanding of the effects of the angle of attack and the angle of yaw on the development and interaction of vortices and the aerodynamic characteristics of the delta wing at a freestream velocity of 20 m/s. The present computations provide qualitatively reasonable predictions of vortical flow characteristics, compared with past wind tunnel measurements. In the presence of a leading edge extension, a significant change in the suction pressure peak in the chordwise direction is much reduced at a given angle of attack. The leading edge extension can also stabilize the wing vortex on the windward side at angles of yaw, which dominates the vortical flows over yawed delta wings.

• Journal of the Korean Society of Food Culture
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• v.36 no.3
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• pp.256-264
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• 2021

The purpose of this study is to observe the influence education experience (home, school, and mass media) on reducing practice behavior(purchasing, using, disposing and leading) of food-related wastes. The study also sought to promote strategy and suggest effective activation plans for the vitalization of behavior of reducing food-related wastes. The study subjects were 412 adult consumers who answered a structured questionnaire. The main findings are as follows: First, the scores of home education experience were 3.61±0.71, which was the highest, and 3.45±0.74 for school education experience, which was the lowest. Second, according to factor analysis, the reducing practice behavior of food-related wastes was converged purchasing, using, disposing and leading behavior. The scores of disposing behavior were 3.79±0.67, which was the highest, and 2.87±0.82 for leading behavior, which was the lowest. Third, the common variables influencing the reducing practice behavior(purchasing, using, disposing and leading) of food-related wastes were home education and mass media and the powerful variable influencing was home education. The results of this study can be used as basic data for the development of educational programs for effective food-related waste reduction.

• Journal of Ship and Ocean Technology
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• v.8 no.2
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• pp.13-19
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• 2004

Jet flows applied tangential to a foil surface near the leading and/or trailing edges increase the lift of the foil by delaying the separation also known as the Coanda effects. Many experimental and numerical studies have proven the effectiveness of Coanda effects on circulation control and the effects have been found to be useful in practical application in many aerodynamics fields. Most of the previous works have studied the effects of the jet blowing near the trailing edges and investigated the influence of jet momentum on lift. A few experimental studies, however, focused on the separation bubble that develops near the leading edge and applied jet flow the edge to remove the bubble but only to find decrease in lift. In the present paper, a Coanda foil of 20% thickness ellipse with modified rounded leading and trailing edges was investigated, and the flow around the foil was numerically studied. The blowing around the leading edge only decreased the lift, as the experiments showed, but the suction considerably increased the lift.

• Journal of Mechanical Science and Technology
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• v.18 no.3
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• pp.481-490
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• 2004

Steady state flow calculations are executed for turbo-pump inducers of modern design to validate the performance of Tascflow code. Hydrodynamic performance of inducers is evaluated and structure of the passage flow and leading edge recirculation are also investigated. Calculated results show good coincidence with experimental data of static pressure performance and velocity profiles over the leading edge. Upstream recirculation, tip leakage and vortex flow at the blade tip and near leading edge are main sources of pressure loss. Amount of pressure loss from the upstream to the leading edge corresponds to that of whole pressure loss through the blade passage. The viscous loss is considerably large due to the strong secondary flow. There appears more stronger leading edge recirculation for the backswept inducer, and this increases the pressure loss. However, blade loading near the leading edge is considerably reduced and cavitation inception delayed.

• Clinical and Experimental Pediatrics
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• v.49 no.12
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• pp.1257-1262
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• 2006

The age of puberty represents a very critical time in the life history of every young woman. The menarche stands as primary indicator of the onset of sexual maturation in females. By late adolescence, 75% of girls experience some problem associated with menstruation. Delayed, irregular, painful, and heavy menstrual bleeding are leading reasons for physician office visits by adolescents, and dysmenorrhea is the leading reason for school absenteeism among girls. This article discusses normal menstrual function during adolescence, then reviews the clinical presentation, evaluation, and management of adolescent dysmenorrhea, dysfunctional uterine bleeding, amenorrhea, and polycystic ovary syndrome.

• Journal of computational fluids engineering
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• v.20 no.2
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• pp.37-45
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• 2015

A parametric study on the shapes of bobsleigh bumpers has been performed to reduce the aerodynamic drag. Effects of geometric parameters, such as leading angle of leading bumper, the ratio of minimum width to maximum width of leading bumper, the ratio of leading bumper length to trailing bumper length, trailing angle of trailing bumper, and the ratio of bumper height to installation location of bumper from the bottom of bobsleigh, on the aerodynamic performance of the bobsleigh were estimated using 3-D Reynolds-averaged Navier-Stokes equations. The turbulence was analyzed using the shear stress turbulence model. Reynolds number based on the hydraulic diameter of the external flow channel was in the range of 150,000~1,000,000. Numerical results for drag coefficient were validated compared to experimental data. Ranges of the five geometric parameters were determined according to the rule of Federation Internationale de Bobsleigh et de Tobaganning. The aerodynamic performance of the bobsleigh sled was most sensitive to the leading angle of leading bumper and the ratio of minimum width to maximum width of leading bumper.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.11
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• pp.888-895
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• 2006

The present study has been conducted to investigate the effects of Reynolds number on heat/mass transfer and pressure drop characteristics in a rotating smooth two-pass duct. For stationary cases, the heat/mass transfer and pressure drop Is decreased on turning region of both leading and trailing surfaces as Reynolds number increases. For rotating cases, increment of Reynolds number affects differently the heat/mass transfer and pressure drop on the leading and trailing surfaces. In the first pass, for example, the heat/mass transfer on the leading surface is greatly increased, though the heat/mass transfer on the trailing surface is almost the same. The reason is that effect of the main flow is more dominant than effect of secondary flow. In particular, it gave decrement of the heat/mass transfer and the pressure drop at turning region and upstream region of second pass for both non-rotating and rotating cases.