• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2002.10a
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• pp.169-172
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• 2002

In this study, the effects of the number of coat and immersion period on strength properties, waterproofness and chemical resistance of painted and immersed cement mortars using two admixture were examined. Test results showed that the flexural and the compressive strengths of the coated and immersed cement mortars increase with increasing number of coat and immersion period. The water absorption of the coated and immersed cement mortars tended to decrease with increasing number of coated and immersion period. In the case of the change of weight and the immersion period for the solutions, a decreasing tendency was shown as the immersion period increases regardless of solution, with a little variation.

• International journal of advanced smart convergence
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• v.9 no.1
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• pp.163-171
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• 2020

There are many differences in narrative delivery between common movies and Virtual Reality(VR) films due to their differences in the appreciation structure. In VR films, scene changes by cuts have hindered the immersion of the audience instead of promoting narrative delivery. There are a range of experiments on narratives and immersion to solve this issue in VR films. Floating Tent applies hand gestures and immersive effects found in game elements and does not disturb narrative delivery by setting proper spaces and employing a direction technique to enable the melting of narratives into the characteristics of the spaces. There are time limits to offsound and mission performance, and devices fit for apocalyptic spatial expressions are made through a program. One of measures for the increasingly growing interactive storytelling in VR films is effective immersion. In narrative delivery, it is important to consider spatial setting and immersion to enable active intervention into events for immersion rather than passive audience only supposed to watch characters' acting.

• Advances in aircraft and spacecraft science
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• v.2 no.3
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• pp.249-261
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• 2015

The mechanical characterization of composite materials is nowadays a major interest due to their increasing use in the aeronautic industry. The design of most of these materials is based on their stiffness, which is mainly obtained by means of tensile tests with strain gauge measurement. For thin laminated composites, this classical method requires adequate samples with specific orientation and does not provide all the independent elastic constants. Regarding ultrasonic characterization, especially immersion technique, only one specimen is needed and the entire determination of the stiffness tensor is possible. This paper presents a study of different methods to determine the mechanical properties of transversely isotropic carbon fibre composite materials (gauge and correlation strain measurement during tensile tests, ultrasonic immersion technique). Results are compared to ISO standards and manufacturer data to evaluate the accuracy of these techniques.

• Journal of the Korean Society for Nondestructive Testing
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• v.24 no.4
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• pp.348-353
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• 2004

This study is aimed for the implementation of ultrasonic method to assess the reliability of turbine bearings. A modified ultrasonic immersion technique was carried out in both laboratory experiment and field application. From the laboratory results, we confirmed that the condition of interface layer between the babbitt and base metal be monitored by the C-Scan. The C-scan image by the ultrasonic immersion test can be used successfully to observe the condition of interface layer. The testing with a focused transducer provides a promising approach for estimating the extent of the damaged region and observing the interface layer effectively. The difference of the ultrasonic reflection ratio between the bonding and debonding area at the interface layer is one of the key parameters for assessing the extent of the damaged area; additionally, the reflection amplitude exhibits a favorable correlation with the overall damage level. The technique developed in this study was applied to the inspection of the turbine bearings at several power plants in Korea whereby the applicability in the field can be ascertained.

• The Journal of Information Systems
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• v.31 no.1
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• pp.219-238
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• 2022

Purpose The purpose of this study is to investigate the structural relationships between interest, interaction level, presence, which are the characteristics of metaverse, learning immersion, and learning satisfaction, which are learning factors. Design/methodology/approach A questionnaire survey technique was used to achieve the purpose of the study. A questionnaire survey was conducted from November 22 to December 5, 2021, with students with experience in non-face-to-face classes using Gather Town and a total of 114 copies of the questionnaire excluding those with insincere answers were used for empirical analysis. SPSS Win ver.23.0 was used for basic statistical analysis, and AMOS 22.0 was used for the establishment and analysis of a structural equation model. Findings According to the study findings, interest and interaction levels had effects on learning immersion and learning presence, self-efficacy on learning presence, and learning immersion and learning presence on learning satisfaction. This study is meaningful in that it conducted an empirical study to find variables for improving learning immersion by conducting classes based on metaverse. Based on the findings of this study, it was found that interest and interaction, which are the biggest characteristics of metaverse, sustain learning participation and immersion and increase presence thereby enhancing learning satisfaction so that the possibilities of metaverse as a next generation education platform passing the limit of existing real time video platforms can be peeped.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.2
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• pp.262-267
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• 2008

Plasma immersion ion beam (PIIB) nitriding process is an environmentally benign and cost-effective process, and offers the potential of producing high dose of nitrogen ions in a way of simple, fast and economic technique for the high plasma flux treatment of large surface area with nitrogen ion source gas. In this report PIIB nitriding technique was used for nitriding on austenite stainless steel of AISI304 with plasma treatment at $250{\sim}500^{\circ}C$ for 4 hours, and with the working gas pressure of $2.67{\times}10^{-1}$ Pa in vacuum condition. This PIIB process might prove the advantage of the low energy high flux of ion bombardment and enhance the tribological or mechanical properties of austenite stainless steel by nitriding, Furthermore, PIIB showed a useful surface modification technique for the nitriding an irregularly shaped three dimensional workpiece of austenite stainless steel and for the improvement of surface properties of AISI 304, such as hardness and strength

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.11
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• pp.18-23
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• 2019

The oil immersion method can be used to create objective lenses with long working distances without sacrificing the focusing resolution for laser processing. In this study, a space in which air or oil can be filled was formed in the middle of a lens for analyzing the optical properties of a liquid-oil immersion lens. As the refractive media, air and oils of different refractive index values (1.2 and 1.5, respectively) were used. A simulation was conducted in the ZEMAX software environment using the ray-tracing technique, and the performance of the oil immersion lens was verified by determining its image distortion and focal length (FL) in each medium. In the case of air, the calculated FL was 0.813 mm, whereas the imaged FLs were 1.594 mm and 8.126 mm when the refraction indices were 1.2 and 1.5, respectively. The FL of an oil immersion lens could be increased considerably. In terms of image distortion, the oil immersion lens exhibited little distortion at the center in all cases, but different degrees of image distortion were observed at different points away from the center depending on the refraction index degree.

• Journal of the Korean Society for Nondestructive Testing
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• v.37 no.2
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• pp.84-90
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• 2017

An ultrasonic synthetic aperture focusing technique (SAFT) using a root mean square (RMS) velocity model is proposed for pulse-echo immersion testing to improve the computational efficiency. Considering the immersion ultrasonic testing of a steel block as an example, three kinds of imaging were studied (B-Scan, SAFT imaging based on ray tracing technology and RMS velocity). The experimental results show that two kinds of SAFT imaging have almost the same imaging performance, while the efficiency of RMS velocity SAFT imaging is almost 25 times greater than the SAFT based on Snell's law.

• Journal of the Korean Society for Nondestructive Testing
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• v.28 no.1
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• pp.40-45
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• 2008

Immersion ultrasonic testing (UT) was used to determine elastic moduli of solid materials instead of the widely-used contact UT method. Conventionally, immersion UT is only used for determining the longitudinal wave speed. However, in this research, transverse wave speed was measured through finding transverse wave echoes caused by mode-conversion at material's boundary. Also, even in the cases when wave speeds could not be determined due to unknown thickness, Poisson's ratio was able to be calculated from the ratio of longitudinal and transverse wave speeds. This technique was verified for several materials, and it was found that higher accuracy was obtained by immersion UT method for materials either with relatively high wave speed or with relatively small Poisson's ratio. This technique thus will be suitable fur ceramics or high strength materials.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.3
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• pp.297-302
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• 2014

The AR(Augmented Reality) is the technique that make the fusion between real world and virtual object. The augmented object on real world can provide the visualization of digital information to user. Also, the real-time AR system makes the interaction between user and computers. Therefore, the immersion of user be increasing and help the information transfer to user with AR system. In this paper, we implement the AR system with the modeled VRML as a three-dimensional object using programming language. The application technique is proposed that augment the various virtual clothes to three-dimensional avatar. Moreover, we propose the novel interface by using marker that can be increase the immersion of user.