• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.24-25
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• 2017

Ambient temperature has a direct impact on the hydraulic process. Though -any experiments have been processed in order to investigate the hydration properties under the various ambient temperature of OPC, there are not reported about aluminate-based composite. This presentation is composed of contents on the experimental investigation of the hydration heat of pulverized rapid cooling ladle furnace slag based composite. Based on the experimental outcomes, gypsum can decrease the hydration heat dramatically and lower ambient temperature has a negative effect on accelerated the hydraulic process.

• Structural Engineering and Mechanics
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• v.10 no.5
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• pp.505-516
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• 2000

This paper is a presentation of an experimental study about the elastic-partly plastic behavior of rectangular hollow steel pinned struts subjected to static cyclic axial loading and the evaluation of the compressive strength of retrofitted crooked struts. Retrofitting is achieved by welding stiffening plates along the webs of damaged struts. The material follows a quasi-kinematic hardening hysteresis path as observed from coupon tests. Test results are compared to those of an analytical model showing a good agreement for both standard and retrofitted struts. The comparison of different stiffener plate dimensions shows that more efficient strengthening is achieved by using long thin stiffeners rather than short thick ones.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.10a
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• pp.57-61
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• 2004

As a kind of application of laser propulsion, air-breathing laser-spike engine can be designed for aircraft in atmospheric flight. Laser-spike engine generates thrust using the blast wave induced by laser energy instead of combustion process. And this engine use air as propellant, therefore, it need no on board propellant. For experimental study, supersonic wind tunnel and spark generator were used. Flow visualization was performed using 2-dimensional laser-spike engine model And numerical simulation of the corresponding case for the experiment was done and compared with experimental case. Detailed results will be discussed at the presentation.

• Advances in nano research
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• v.13 no.2
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• pp.135-146
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• 2022

The accurate assessment of the performance of nonuniform systems requires a thorough understanding of stability analysis. As a result, the theoretical modeling of the influence of various variables on the performance of small-scale nonuniform structures with conventional and non-conventional geometries is presented in this paper. According to the fundamental computer simulation based on mathematical and mechanical principles, the stability of the nonuniform structures is examined. Thus, a numerical procedure is used to simulate the stability and instability characteristics of the nonuniform small-scale structures via computer aid. Theoretic simulation methods provide a great deal of the design and production of small-scale structures at a low cost compared to experimental simulations. Thus, this paper provides a good presentation of the stability analysis of the nonuniform nanoscale structures with high accuracy without actual experimental.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.223-226
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• 2017

With the development of information technology, users are provided with information they want through mobile device in various situations. When users communicate with information, there is interaction through gesture activities such as tapping and experience in the process. Experience through interaction in mobile affect the user's psychology. This is important because it is related to the behavior of the user in the future. Various types of information presentation methods have been researched in mobile environment. However, there are more research focusing on functional interactivity. The purpose of this study is to investigate the effect of interaction and usage mode on satisfaction, usefulness, and intention to use for sound text presentation that is user-centered. As variables for my study, there are two factors which are interactivity and usage mode. The interactivity type is composed of two ways that are: High and Low depending on modality and message interactivity; and the usage mode is composed of Action mode and Goal mode depending on whether user has a task or not. The experimental design is $2{\times}2$. The same content is provided in (a) only Modality interactivity, and (b) Modality and Message interactivity are provided. Depending on usage mode, (a) Action mode is processed without a specific task, and (b) Goal mode is performed with a specific task to participants. The experimental study demonstrated that there is a difference in satisfaction, usefulness, and intention to use depending on the difference of interaction and usage mode when providing information in mobile environment. The results of this study are summarized as follows: interaction and usage mode have significant influence on mobile user's satisfaction, usefulness, intention to use.

• Journal of the Korean Chemical Society
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• v.61 no.4
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• pp.211-217
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• 2017

The purpose of this study was to examine UK students' use of multimodal representations in science. Students were asked to explain their understandings of the scientific concept and presentation of the multimodal representations in a science Assessing Pupils' Progress (APP) task. Participants of this study were fifty-four Year 7 students taught by the same teacher. Students from one class (27 students) were assigned to the experimental group, and then they received instruction encouraging the using of multimodal representations as evidences to support students' claims. One class (27 students) was assigned to the control group and they received instruction with traditional teaching methods. Both groups performed an APP task for assessment. The samples of APP assessments produced by students both from the experimental and control groups were analyzed using an analysis framework of multimodal representations, embeddedness in evidence and understanding of scientific concepts. Data analysis indicated that the students in the experimental group performed better than that of the control group on embeddedness of multimodal representations in the APP task. In addition, there was a significant difference between the two groups in the evaluation of understand of the scientific concepts.

• Journal of the Korean Society for Library and Information Science
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• v.56 no.4
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• pp.239-267
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• 2022

In this study, the adolescents' perception of the Information Search Process(ISP); their anxiety and the need for intervention during the process were investigated based on Kuhlthau's ISP model, and the relationship among the factors was analyzed with structural equations. In addition, the effectiveness of scaffolding strategy to the experimental group during the class was verified. The main findings are as follows. First, as a result of exploring the anxiety felt by learners and the need for intervention in the information search process, it was found that the presentation stage had a significant effect on the anxiety, and the collection, presentation, and assessment stages had significant effects on the need for intervention. Second, as a result of controlling each variable to investigate the anxiety felt by learners and necessity of intervention in the information search process, it was confirmed that among the demographic variables, the difference between the first graders and the second ones was significant; and the difference in the metropolitan area was more significant than that in the Gangwon province. Third, as a result of paired t-test and covariance analysis on the control group and the experimental group, it was confirmed that the anxiety and need for intervention of the experimental group were statistically significantly reduced. The significance of this study lies in the point that it presents a practical basis for applying scaffolding strategies appropriate to information search process in the field of education.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.271-271
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• 2012

Many studies have been investigated on high density plasma source (Electron Cyclotron Resonance, Inductively Coupled Plasma, Helicon plasma) for large area source after It is announced that productivity of plasma process depends on plasma density. In this presentation, we will propose the new concept of the multiple source, which consists of a parallel connection of ICP sources and helicon plasma sources. For plasma uniformity, equivalent power (especially, equivalent current in ICP & Helicon) should distribute on each source. We design power feeding line as coaxial transmission line with same length of ground line in each source for equivalent power distribution. And we confirm the equivalent power distribution with simulation and experimental result. Based on basic study, we develop the plasma source for oxidation in semiconductor process. we will discuss the relationship between the processing parameters (With or WithOut magnet, operating pressure, input power ). In ICP, plasma density uniformity is uniform. In ICP with magnet (or Helicon) plasma density is not uniform. As a result, new design (magnet arrangement and gas distributor and etc..) are needed for uniform plasma density in ICP with magnet and Helicon.

• Child Health Nursing Research
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• v.24 no.4
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• pp.443-453
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• 2018

Purpose: This study was describes the development and implementation a sex education program with a blended learning method for university students. Methods: Sixty-eight university students were recruited either to the experimental group (n=35) or the control group (n=33). This program was developed based on the analysis, design, development, implementation, and evaluation model. The analysis phase consisted of a literature review, focus group interview, expert consultations, and target group survey. In addition, learning objectives and structure were designed, and a printed text-book, presentation slides, cross-word puzzle, and debate topics were developed. In the implementation phase, the program was conducted 3 times over the course of 3 weeks. The evaluation phase involved verification of the effects of the program on sex-related knowledge, sexual autonomy, and justification of violence, as well as an assessment of satisfaction with the program. Results: The experimental group had significantly higher scores on sex-related knowledge (t=5.47, p<.001), sexual autonomy (t=2.40, p=.019), and justification of violence (t=2.52, p=.015) than the control group. Conclusion: The results indicate that this sex education program with blended learning was effective in meeting the needs of university students and can be widely used in this context.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.21-24
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• 2003

The understanding of the mechanism of device degradation has been accomplished recently, for devices using $AlQ_3$ electron transport and emitter molecule. In this presentation the experimental evidence for the degradation mechanism of $AlQ_3$ based devices will be reviewed, showing that the hypothesis of an unstable $AlQ_3^+$ cation explains a large amount of experimental data. This hypothesis, however, explains not only the room temperature device degradation in time but also sheds light on temperature stability of OLEDs. Dependence of half-life of a series of devices with an emitter layer composed of a mixture of $AlQ_3$ and different hole transport molecules (mixed emitter layer) will be discussed when they are operated at elevated temperatures. These results can also be explained in the framework of an unstable $AlQ_3^+$ species. An OLED structure containing a doped mixed emitter layer will be described, which shows extraordinary stability, half-life of 1200 hours at operating temperature of 70 C and initial luminance of 1650 $cd/m^2$. We will also discuss a novel Black $Cathode^{TM}$ OLED with reduced optical reflectivity, which is also stable at elevated temperatures. The new cathode utilizes a conductive light-absorbing layer made of a mixture of metals and organic materials.