• Journal of the Korean Society of Earth Science Education
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• v.12 no.1
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• pp.109-118
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• 2019

The purpose of this study was to investigate the effects of experience as a science experiment assistant teacher on the science instruction anxiety and the science teaching efficacy beliefs of elementary pre-service teachers in a small scale school. For this study, 21 elementary pre-service teachers were selected and then they worked as science experiment assistant teachers in small scale schools for about 10 months. They were tested the science instruction anxiety and the science teaching efficacy beliefs in before and after. After analyzing the tests results, some pre-service teachers were interviewed. The results of this study are as follows. The experiences as science experiment assistant teachers positively influenced on reducing the science instruction anxiety to elementary pre-service teachers. The experiences also had positive effects on reducing both state anxiety and trait anxiety, which are the sub-factors of science instruction anxiety. In addition, the science teaching efficacy beliefs and its sub-factor, the self-efficacy in science teaching, had positive impacts, but the experiences did not have a positive impact on the outcome expectancy. The effects of the experience as a science experiment assistant teacher were different according to the personal experiences and cognitions of pre-service teachers.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.75-75
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• 2022

Traditional agriculture mostly focused on activity in the field, but current agriculture faces problems such as reduction of agricultural inputs, labor shortage and so on. Accordingly, traditional agricultural experiments generally considered the simple treatment effects, but current agricultural experiments need to consider the several and complicate treatment effects. To analyze such several and complicate treatment effects, data collection has the first priority. Remote sensing is a quite effective tool to collect information in agriculture, and recent easier availability of UAVs (Unmanned Aerial Vehicles) enhances the effectiveness. LAI (Leaf Area Index) is one of the most important information for evaluating the condition of crop growth. In this study, we utilized UAV with multispectral camera to evaluate plant-based LAI of sweetcorn in a small-scale field experiment and discussed the feasibility of a new experimental design to analyze the several and complicate treatment effects. The plant-based SR measured by UAV showed the highest correlation coefficient with LAI measured by a canopy analyzer in 2018 and 2019. Application of linear mix model showed that plant-based SR data had higher detection power due to its huge number of data although SR was inferior to evaluate LAI than the canopy analyzer. The distribution of plant-based data also statistically revealed the border effect in treatment plots in the traditional experimental design. These results suggest that remote sensing with UAVs has the advantage even in a small-scale experimental plot and has a possibility to provide a new experimental design if combined with various analytical applications such as plant size, shape, and color.

• Journal of the Earthquake Engineering Society of Korea
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• v.7 no.6
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• pp.101-108
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• 2003

Small-scale models have been frequently used for experimental evaluation of seismic performance because of limited testing facilities and economic reasons. However, there are not enough studies on similitude law for analogizing prototype structures accurately with small-scale models, although conventional similitude law based on geometry is not well consistent in the inelastic seismic behavior. When fabricating prototype and small-scale model of reinforced concrete structures by using the same material. added mass is demanded from a volumetric change and scale factor could be limited due to size of aggregate. Therefore, it is desirable that different material is used for small-scale models. Thus, a modified similitude law could be derived depending on geometric scale factor and equivalent modulus ratio. In this study, compressive strength tests are conducted to analyze equivalent modulus ratio of micro-concrete to normal-concrete. Equivalent modulus ratios are divided into multi phases, which are based on ultimate strain level. Therefore, an algorithm adaptable to the pseudodynamic test. considering equivalent multi-phase similitude law based on seismic damage levels, is developed. In addition, prior to the experiment. it is verified numerically if the algorithm is applicable to the pseudodynamic test.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1592-1597
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• 2004

Experimental studies were carried out to confirm the turbulent enhancement of the cooling system of nuclear reactor by large scale vortex generation in nuclear fuel rod bundle. The large scale vortex motions were generated by rearranging the inclination angles of mixing vanes to the coordinate directions. Experimental studies were carried out at Reynolds Number 60,000 with hydraulic condition. Normal variations of mean velocity and turbulent intensity in the rod bundle subchannel were measured by the 2-color LDV measurement system. The turbulence generated by split mixing vanes has small length scales so that they maintain only about 10DH after the spacer grid. On the other hand, the turbulences generated by the large scale vortex continue more and remain up $25D_{H}$ after the spacer grid.

• The Korean Journal of Pain
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• v.31 no.1
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• pp.10-15
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• 2018

Background: To identify a new strategy for postoperative pain management, we investigated the analgesic effects of allopregnanolone (Allo) in an incisional pain model, and also assessed its effects on the activities of the primary afferent fibers at the dorsal horn. Methods: In experiment 1, 45 rats were assigned to Control, Allo small-dose (0.16 mg/kg), and Allo large-dose (1.6 mg/kg) groups (n = 15 in each). The weight bearing and mechanical withdrawal thresholds of the hind limb were measured before and at 2, 24, 48, and 168 h after Brennan's surgery. In experiment 2, 16 rats were assigned to Control and Allo (0.16 mg/kg) groups (n = 8 in each). The degree of spontaneous pain was measured using the grimace scale after the surgery. Activities of the primary afferent fibers in the spinal cord (L6) were evaluated using immunohistochemical staining. Results: In experiment 1, the withdrawal threshold of the Allo small-dose group was significantly higher than that of the Control group at 2 h after surgery. Intergroup differences in weight bearing were not significant. In experiment 2, intergroup differences in the grimace scale scores were not significant. Substance P release in the Allo (0.16 mg/kg) group was significantly lower than that in the Control group. Conclusions: Systemic administration of Allo inhibited mechanical allodynia and activities of the primary afferent fibers at the dorsal horn in a rat postoperative pain model. Allo was proposed as a candidate for postoperative pain management.

• 한국연소학회:학술대회논문집
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• 2002.11a
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• pp.231-235
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• 2002

A theoretical and experimental study on the combustion process in a constant volume micro combustor is described. Unlike in a macro scale constant volume combustor, the heat loss to the wall plays a major role in flame propagation in a micro micro combustor. In order to analyze the effect of heat loss on combustion phenomena, pressure transition from ignition was measured. A number of cylindrical micro combustors with different diameter and depth were used for experiment to study the effect of length scales and shape factor. The diameter of combustor ranged from 7.5mm to 22.5 mm and the height of cylinder was from 1mm to 4mm. Initial pressure was also varied for the experiment. The diagnostic methods were severely limited due to the size of the apparatus and uncertainties of certain quantities to be measured in a small-scale environment. An analytical method to derive physical quantities that are essential for performance prediction from the pressure measurements is described.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.9
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• pp.98-107
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• 2009

Actually, The hard switching high frequency PWM DC-DC converters are existing accompany, the high frequency of pulse modulation carrier frequency increase of switching loss of power semiconductor switching elements, there are have some problem points of EMI etc. This compliance with a voltage surge or the electric current surge are where the switching transient phenomenon accompanies. In order to solve like this problem effectively it described the principle of operation of New Small Scale Boost PWM Chopper circuits from the present paper, draw Characteristics from simulation and experiment.

• Solar Energy
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• v.12 no.1
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• pp.95-102
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• 1992

A small scale solar collector system composed of a Fresnel lens of $0.5m^2$ area as a solar concentrator and a compact fluidized-bed solar receiver was developed. Performance and temperature distribution in the fluidized bed receiver were measured using SiC for particles and air for working fluid. The maximum gas temperature was attained up to 1250K at this moment. In this study, energy efficiency achieved by the present experiment was high for the small scale solar collector system and compact receiver.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.181-188
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• 2008

In this study, estimation of behavioral characteristics between twin tunnels was performed through the series of laboratory experiment on the small scale tunnel model. In the model test, the experimental parameters were geological conditions, center to center distance between twin tunnels, application of discontinuous inclination. To estimated behavior of pillar and load-displacement relationship by model tests and numerical analyses.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.10
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• pp.967-974
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• 2011

The direct and indirect PFBEM(power flow boundary element method) for the treatment of the 3 dimensional multi-domain problems are proposed to predict the acoustic energy density in medium to high frequency ranges. In the proposed method, the equation is derived in a matrix form by considering coupled relationships of the power flow at the interface of given domains. The proposed method can successfully obtain the analytical solutions for the problems of coupled cubes and the small-scale reverberant chamber. Then the experiment is carried out to obtain STL(sound transmission loss) by using small-scale reverberant chamber and the results are compared with analysis results.