• Journal of The Korean Association For Science Education
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• v.26 no.5
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• pp.660-673
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• 2006

There have been many attempts to determine the value and the role of school laboratory experiment, but it seems hard to find consensus among these attempts from the perspective of education. This difficulty seems mainly due to disagreement on the concept of education, which has caused an instrumental attitude considering the school laboratory only as a means of developing science or pursuing various functions of school. However, the Endogenous Theory of Education (ETE), which claims education as 'a form of life', has recently paved the way for laboratory experiment to be justified as an opportunity of 'educooperation' allowing students to experience the intrinsic values of education in the medium of science. According to this theory, it is not the detailed practicals but the whole context where the laboratory activity is situated that matters in revealing the inherent educational phenomena. Through this new perspective, I observed two biology laboratory classes in a high school and analyzed the pattern of teacher-student and student-student interactions. Some meaningful educooperation was found in students' chattering, which has been traditionally considered as merely noise in the classroom, rather than in teacher-student interactions. This study discusses the reasons for these findings in detail and culminates in suggesting ways for accentuating the educational aspect of school laboratory activity.

• Nuclear Engineering and Technology
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• v.52 no.1
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• pp.59-68
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• 2020

ECCMIX component was introduced in RELAP5/MOD3 for calculating the interfacial condensation. Compared to other existing components in RELAP5, user experience of ECCMIX component is restricted to developmental assessment applications. To evaluate the capability of the ECCMIX component, ECCS experiment was conducted which included single-phase and two-phase thermal mixing. The experiment was carried out with test sections containing a main pipe (70 mm inner diameter) and a branch pipe (21 mm inner diameter) under the atmospheric pressure. The steam mass flow in the main pipe ranged from 0 to 0.0347 kg/s, and the subcooled water mass flow in the branch pipe ranged from 0.0278 to 0.1389 kg/s. The comparison of the experimental data with the calculation results illuminated that although the ECCMIX component was more difficult to converge than Branch component, it was a more appropriate manner to simulate interfacial condensation under two-phase thermal mixing circumstance, while the two components had no differences under single-phase circumstance.

• Nuclear Engineering and Technology
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• v.49 no.8
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• pp.1748-1751
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• 2017

Reduced activation ferritic/martensitic (RAFM) steels are widely applied as structural materials in the nuclear industry. To investigate hydrogen's effect on RAFM steels' elastic properties and the mechanism of that effect, a procedure of first principles simulation combined with experiment was designed. Density functional theory models were established to simulate RAFM steels' elastic status before and after hydrogen's insertion. Also, experiment was designed to measure the Young's modulus of RAFM steel samples with and without hydrogen charging. Both simulation and experiment showed that the solubility of hydrogen in RAFM steels would decrease the Young's modulus. The effect of hydrogen on RAFM steels' Young's modulus was more significant in water-quenched steels than it was in tempering steels. This indicated that defects inside martensite, considered to be hydrogen traps, could decrease the cohesive energy of the matrix and lead to a decrease of the Young's modulus after hydrogen insertion.

• Current Applied Physics
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• v.18 no.11
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• pp.1403-1409
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• 2018

In the present study, the $SrMoO_4:Eu^{3+}$ phosphors has been synthesized through hydro-thermal co-precipitation method, and single factor and orthogonal experiment method was adopted to find optimal synthesis condition. It is interesting to note that hydro-thermal temperature is a prominent effect on the luminescent intensity of $SrMoO_4:Eu^{3+}$ red phosphor, followed by co-precipitation temperature, calcining time, and the doping amount of $Eu^{3+}$. The optimal synthesis conditions were obtained: hydro-thermal temperature is $145^{\circ}C$, co-precipitation temperature is $35^{\circ}C$, the calcining time is 2.5 h, and the doping amount of activator $Eu^{3+}$ is 25%. Subsequently, the crystalline particle size, phase composition and morphology of the synthesized phosphors were evaluated by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The results show that these phosphors possess a scheelite-type tetragonal structure, and the particle size is about $0.2{\mu}m$. Spectroscopic investigations of the synthesized phosphors are carried out with the help of photo-luminescence excitation and emission analysis. The studies reveal that $SrMoO_4:Eu^{3+}$ phosphor efficiently convert radiation of 394 nm-592 and 616 nm for red light, and the luminescence intensity of $SrMoO_4:Eu^{3+}$ phosphors is improved. $SrMoO_4:Eu^{3+}$ phosphors may be a potential application for enhancing the efficiency of white LEDs.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.1
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• pp.28-35
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• 1999

The effects of addition of celulases (A cremonium cellulolyticus and Trichoderma viride, CE), a commercial inoculum containing lactic acid bacteria (Lactobacillus casei, LAB), fermented green juice (macerated napier grass with water was incubated anaerobically with 2% glucose for 1 day, FGJ) and glucose (G), and regional difference of ensiling on napier grass (Pennisetum purpureum Schum.) silage were studied by using 900 ml laboratory glass bottle silos under 30 and $40^{\circ}C$ storage conditions in 1995 and 1996. Experiment 1 was carried out to compare the addition of CE, LAB, FGJ and the combinations. Silages were stored for 45 days after ensiling. Experiment 2 studied the effects of applications of CE, LAB, FGJ and G. Experiment 3 was carried out using the similar additives as experiment 2 except for LAB. Silages were stored for 60 days in the experiments 2 and 3. Experiments 1 and 2 were done in Nagoya, and experiment 3 in Okinawa. Sugar addition through CE or G improved the fermentation quality in all the experiments, which resulted in a greater decrease in the pH value and an increased level of lactic acid, while butyric acid contents increased under $30^{\circ}C$ storage condition in CE addition. LAB and FGJ additions hardly affected the silage fermentation quality without additional fermentable carbohydrate. But the combination of LAB, FGJ and glucidic addition (CE and G) improved the fermentation quality. The effect of the regional difference of ensiling between temperate (Nagoya; $35^{\circ}$ N) and subtropical (Okinawa; $26.5^{\circ}$ N) zones on silage fermentation quality was not shown in the present study.

• International Journal of Fluid Machinery and Systems
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• v.3 no.1
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• pp.80-90
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• 2010

The cavity oscillation with swirling flow in hydraulic power generating systems was studied by a simple experiment and numerical simulation. Several types of fluctuation were observed in the experiment, including the cavitation surge caused by the diffuser effect and the vortex precession by the swirling flow. Both cavitation surge and vortex precession were simulated by CFD. Detailed flow structure was examined through flow visualization and CFD.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.1
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• pp.84-88
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• 2002

The effect of dietary xylitol on growth performance and nitrogen retention was studied in male broiler chicks during immunological stimulation. In experiment 1, chicks (10 day of age) were fed a corn-soybean diet containing 10% glucose or 10% xylitol with identical metabolizable energy and crude protein for 14 days. In experiment 2, ten-day-old chicks were fed 10% glucose or 6% xylitol diet for 8 days. During the final 6 days of the experimental periods, a half of birds fed each diet were injected intraperitoneally with 0.5 mg/kg body weight of Escherichia coli lipopolysaccharide (LPS, 0127:B8) on days 1, 3 and 5, and with 250 mg/kg body weight of Sephadex-G50 superfine on days 2 and 4 to stimulate immune system in both experiments. Feeding of the xylitol diets partially prevented the reduction in body weight gain or feed efficiency due to LPS and Sephadex injections, but the glucose diet did not in both the experiments. LPS and Sephadex injections decreased nitrogen retention, whereas the diet containing xylitol partly in experiment 1 and almost completely in experiment 2, prevented the reduction due to immunological stimulation. These results indicate that dietary xylitol probably prevents the reduction in nitrogen retention with growth retardation due to LPS and Sephadex injection. The beneficial effect on nitrogen retention is obtained when chicks are given xylitol 2 days before stimulating the immune system.

• Journal of Korean Elementary Science Education
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• v.38 no.2
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• pp.203-215
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• 2019

The purpose of this study is to clarify the roles of laboratory work in school. Twenty-one literatures were identified about roles of laboratory work in school by applying criteria such as published in CI level journals or used as a reference over 100 times during 1960-2017. Twenty-one literatures were reviewed according to periods such as 1960-1989, 1990-2003, and 2004-2017, and identified the roles of laboratory work in school that commonly presented in more than two literature. Seven roles of laboratory work in school identified were as follows (a) learning scientific knowledge, (b) enhancing attitude toward science, (c) learning scientific inquiry methods, (d) acquiring skills to use specific laboratory instruments, (e) enhancing scientific attitude, (f) understanding the nature of science(NOS), and (g) providing opportunity to experience natural or scientific phenomena. The results of this study can be used to provide school teachers and students a clear meaning of the roles of laboratory work in school.

• Journal of The Korean Association For Science Education
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• v.9 no.1
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• pp.75-89
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• 1989

Secondary schools in Korea have been faced with several critical problems with regard to science education. Among them one of the most fundamental problems is associated with laboratory-based science education. There fore as a part of research project for the improvement of science education in secondary schools, this study had its abjectives to inquire into the following areas related to laboratory experiment. ${\circ}$Survey and analysis of theoretical backgrounds for science teaching focused on laboratory experiments. ${\circ}$Status survey of experiment-based science teaching in high schools. ${\circ}$Development of model for improving experiment-based science teaching. In order to fulfill these objectives this study used methods of eiterature review, survey, and interviews. The major finding are as follows : ${\circ}$Some topic for laboratory experiments as oppeared in the textbooks are not appropriate in the light of sience curricular operations in high schools. ${\circ}$In some schools equipments and facilities of school laboratories are for from sufficiency. ${\circ}$Laboratory experiments are not financially supportel for ideal science teach in both middle schools and high schools. These are not on exhaustive list of findings from this study More finding and teaching model for improvement of science education are also described in this paper.

• Journal of The Korean Association For Science Education
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• v.28 no.4
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• pp.331-339
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• 2008

The aim of this study was to compare the effectiveness of microcomputer-based laboratory (MBL) with the traditional laboratory experiment on science classes in middle school. MBL tools were developed and applied for five experiment subjects chosen from middle school science textbook for MBL experiment classes, while usual experiment methods suggested in the textbook were used in traditional experiment classes. In order to evaluate the effects of MBL experiment class, achievement, graphic ability, science process skills, affective aspect related to science were tested before and after applying the MBL experiment. The result revealed that MBL experiment class was more effective than traditional experiment class in improving student's science achievement, science process skills, and graphic ability. The result also indicated that there was a significant difference between experiment and control group with regards to the effect on affective aspect related to science. From the above result, we can find the positive implication of applicability of MBL experiment as a new experiment tool at the early stage of introduction in a real context.