• Journal of Advanced Marine Engineering and Technology
• /
• v.22 no.1
• /
• pp.108-116
• /
• 1998

In this paper it is investigated the roles of key elementary reactions for NO formation in methane-air one-dimensional premixed flame and counterflow diffusion flame, which were studied numerically by using NO kinetics and $C_{2}$ -chemistry complied by Miller and Bowman. The spatial distributions of the reaction rates of 9 main elementary reactions directly related to NO formation and destruction were calculated. Integration of the rates of all reactions in the NO formation across the flame yields the quantitative reaction path diagram, which shows clearly relative importance of each reaction path in NO formation and how it changes with the type and parameters of the flame. The results show that the thermal and Fenimore mechanisms are dominant respectively for learn and rich premixed flames, and the latter is dominant for diffusion flames. In addition, it was found that the HCN recycle route is important for diffusion flame, and that the routes of mutual transformation between NO and NO$^{2}$, and between NO and HNO do not contribute to the net NO formation.

• Journal of applied mathematics & informatics
• /
• v.28 no.5_6
• /
• pp.1545-1552
• /
• 2010

It is interesting to know the behavior of a network from its structure. One interesting topic is to find a relation between the existence of a positive equilibrium of the reaction network and its structure. One approach to study this topic is using the concept of deficiency. In this work, we develop an algorithm and show an elementary proof of the relation based on the algorithm and deficiency.

• Journal of The Korean Association For Science Education
• /
• v.36 no.6
• /
• pp.851-866
• /
• 2016

The purpose of this study is to investigate pre-service elementary teachers' views of the law of action-reaction by examining their degrees of understanding and Typically-Perceived-Situations (TPS). Data were collected from 177 Grade 3 pre-service elementary teachers. The results of analyzing these data show: First, the participants did not sufficiently understand about the law of action-reaction, and their degrees of understanding were different depending on the situation provided in the questionnaire. Second, in relation to the TPSs of the law of action-reaction, the participants thought of irrelevant situations to the law of action-reaction such as "a situation generated by inertia" as well as commonly relevant ones such as "a person pushing a wall", and had somewhat biased TPSs in terms of 'action type' and 'result motion type' of action-reaction. Finally, several suggestions on the science education for promotion of understanding about the law of action-reaction were given.

• Korean Chemical Engineering Research
• /
• v.46 no.2
• /
• pp.301-309
• /
• 2008

In this study, the effect of formaldehyde to phenol (F/P) molar ratios, catalyst wt%, and reaction temperature on the chemical structure was studied utilizing a two-level full factorial experimental design. The effect of three variables on the chemical structure was analyzed by using three-way ANOVA of SPSS. Concentration of methyrol-substituted phenols after 300 min addition reaction increased with higher the F/P mole ratio, lower the reaction temperature and lower the catalyst wt%. Resol catalysed by barium hydroxide showed higher addition of formaldehyde onto ortho positions of phenolic rings. A simplified elementary reaction model for resole type phenolic resin formation which do not consider the dissociation of phenolic compounds and the fraction of formaldehyde in the form of methylene glycol was proposed and compared with Zavitsas' type models. Elementary reaction model showed error of 2.79% compared to the error of 3.27% in Zavitsas' type models. It was thought that the elementary reaction model could be used to predict the behavior of addition reaction in resol formation.

• The Korean Journal of Elementary Counseling
• /
• v.9 no.1
• /
• pp.1-20
• /
• 2010

This research was carried out to see that to what extent KSD reaction can be related to types of sociometric status, and it was carried out on the basis of an hypothesis that KSD reactions of elementary school students in high grades(4th, 5th, 6th grades) would vary according to gender and 5 types of sociometric status, For that purpose, sociometry which were developed by Ahn Iehwan(2007) and KSD, were implemented with students of 20 classes (5 classes of 4th grade, 5 classes of 5th grade and 10 classes of 6th grade) at an elementary school in A city. Number of students surveyed was 366 and it was not exactly the stratified cluster sampling method. To verify 3 hypotheses, independent samples t-test, one way ANOVA, discriminant analysis were made. As a result, there was statistically significant difference in action factor and characteristics factor among 3 factors of KSD reaction by gender, but there was not statistically significant difference in dynamics factor. The result of one way ANOVA showed there was statistically significant difference in characteristics factor and dynamics factor among female students, but there was not statistically significant difference in action factor. Therefore, it was understood that characteristics factor of KSD reaction was closely related to gender difference and types of sociometric status. From the result of this research, it was considered necessary to review KSD scoring system suggested by 田中志帆(2009). And lastly, it was observed that KSD reaction was not effective in evaluating sociometry, and a new approach to the projective drawing test was suggested as a supplementary method for sociometry.

• Korean Chemical Engineering Research
• /
• v.47 no.3
• /
• pp.380-385
• /
• 2009

The absorption rate of carbon dioxide with 2-amino-2-methyl-1-propanol(AMP) was measured in such non-aqueous solvents as methanol, ethanol, n-propanol, n-butanol, ethylene glycol, propylene glycol, and propylene carbonate, and in water at 298 K and 101.3 kPa using a semi-batch stirred tank with a plane gas-liquid interface. The overall reaction rate constant, obtained under the condition of fast reaction regime, from the measured rate of absorption was used to get the elementary reaction rate constants in complicated reactions represented by reaction mechanism of carbamate formation and the order of overall reaction of $CO_2$ with amine. The correlation between the elementary reaction rate constant and the solubility parameter of the solvent was also presented.

• Journal of Korean Elementary Science Education
• /
• v.33 no.4
• /
• pp.784-794
• /
• 2014

In this study, we operated science teacher learning community to enhance professionality of elementary science teachers. 8 participants with various background, which include their science content knowledge, teaching experience and beliefs about teaching, were involved in this study. Bales(1950)'s social interaction process framework was mainly used to understand the members' interaction, focusing particularly on process aspects not on contents aspects. The data analysis shows that the members in the science teacher learning community tried their best to maintain the positive reaction to other members in most occasions in the community meetings. On the other hand, there were also negative reaction process due to their different ideas and views, causing their emotional conflicts in some social relations and dialogical situations. Nevertheless, the results also imply that the dual reaction processes, which are positive and negative processes, are equally important to facilitate science teachers' professional knowledge and experience. The educational meanings are discussed in the aspects of science teacher education.

• Journal of Advanced Marine Engineering and Technology
• /
• v.23 no.1
• /
• pp.88-95
• /
• 1999

This study investigates the effects of different kind fuels on the flame structure by using the numerical simulation in triple flame made by a co-flowing fuels-air stream based on the elementary chemical reaction mechanism. Methane and Hydrogen were used as fuel for this study. In order to interpret the result of the study on numerical simulation Skeletal chemistry is employe as the elementary chemical reaction mechanism for methane Gutheil's as an offset ele-mentary chemical reaction mechanism for hydrogen. The result of this study is as follows. In com-parison between the apparent burning velocity change of triple flame and the one-dimensional pre-mixed flame hydrogen fuel flame is higher than methane fuel flame. The flame thrusts out for-ward in the down stream of the boundary between air-fuel mixture and air stream and a part of the flow is bent and forks out in this protruding flame so that a triple flame is originated.

• Hwankyungkyoyuk
• /
• v.24 no.3
• /
• pp.18-25
• /
• 2011

This study was conducted to evaluate the effects of volatile organic compounds and formaldehyde of newly-built school classroom indoor air on the neurobehavioral functions of students. The elementary schools that were opened in September 2008(as of September 2008) was selected for newly-built school and the elementary school that were opened in March 2006 was selected for control group schools. The concentration of formaldehyde(HCHO), a hazardous organic compound that exists in the air of classrooms, exceeded the standard value of $108.2{\mu}g/m^3$ in newly-built schools while it was $60.8{\mu}g/m^3$ in control group schools, which is around 60% of the standard concentration. However, the concentration of the total volatile organic compounds(TVOCs) was $788.9{\mu}g/m^3$ and $756.1{\mu}g/m^3$ in newly-built schools and control group schools respectively, which are approximately two times higher than the standard concentration. In newly-built schools, the mean reaction time of additions and symbol digit, respectively 3,020ms and 2,398ms in pre-exposure were increased to 3,167ms and 2,514ms respectively in post-exposure. The difference of mean reaction time between pre and post exposure was 146.8 ms, or 4.6%, and 116.7ms, or 4.8%, respectively, showing statistically-significant increase of reaction time(p<0.05). On the contrary, the difference of reaction time of both tests were not statistically significant in the control group schools. These results showed that the neurobehavioral performance of newly-built schools students were affected by volatile organic compounds and formaldehyde of classroom indoor air.

• The Journal of Korean Academic Society of Nursing Education
• /
• v.18 no.1
• /
• pp.149-158
• /
• 2012

Purpose: The purpose of this study was to identify the factors influencing mental health among late elementary age children. Methods: The research design was a secondary data analysis. Data were collected from 746 students in grades 5 or 6, and analyzed using descriptive statistics, t-test, ANOVA, Pearson's correlation coefficients and stepwise multiple regression with the SPSS/PC 18.0 program. Results: The average score of mental health was $3.42{\pm}0.55$. There were significant differences in mental health according to health status, economic status, scholastic performance, relationships with friends, relationships with the teachers, atmosphere of the home, number of siblings and the source of trouble. Stepwise multiple regression analysis showed influencing factors of stress, negative reaction under stress, self-esteem, teacher support, and friend support support and explained 41.4% of total variance in late elementary age children's mental health. Conclusion: These results may contribute to a better understanding of mental health in late elementary age children. The results of the present study indicate a need to develop nursing interventions to prevent and manage elementary school-age children's negative reaction under stress.