• 한국농공학회:학술대회논문집
• /
• 한국농공학회 2002년도 학술발표회 발표논문집
• /
• pp.169-172
• /
• 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
• /
• 제9권1호
• /
• pp.163-171
• /
• 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
• /
• 제2권3호
• /
• pp.249-261
• /
• 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.

• 비파괴검사학회지
• /
• 제24권4호
• /
• pp.348-353
• /
• 2004

이 연구는 터빈베어링의 신뢰성을 평가하기 위하여 초음파 C-Scan 방법을 적용한 기술이다. 수침법에 관한 연구는 실험실과 현장검사 적용에 광범위하게 사용되는 기술이다. 여기에서는 C-Scan 방법을 이용하여 베어링의 모재와 Babbitt 금속간 경계부의 상태를 평가하였다. 수침법 C-Scan 방법에 의한 초음파 영상은 베어링 경계부의 상태를 확인하는데 효과적인 방법으로 사용될 수 있었다. 초음파 영상의 분해능을 높이기 위하여 집속형 탐촉자를 사용하고, Babbitt 금속과 베어링 모재간의 접합경계면에서 발생하는 초음파 음압 반사율을 측정하여 결함의 검출과 면적을 추정할 수 있었다. 초음파 수침법은 베어링 접합부의 박리위치와 박리면적의 경계면을 결정하여 크기를 계산하는데 아주 유용하게 사용될 수 있는 기술이며, 이 연구에서 개발된 기술은 화력발전소에서 사용되고 있는 터빈베어링의 건전성을 확보하는데 적용되었다.

• 한국정보시스템학회지:정보시스템연구
• /
• 제31권1호
• /
• pp.219-238
• /
• 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
• /
• 제32권2호
• /
• pp.262-267
• /
• 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

• 한국기계가공학회지
• /
• 제18권11호
• /
• pp.18-23
• /
• 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.

• 비파괴검사학회지
• /
• 제37권2호
• /
• pp.84-90
• /
• 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.

• 비파괴검사학회지
• /
• 제28권1호
• /
• pp.40-45
• /
• 2008

고체의 탄성 계수를 구하기 위한 방법으로 초음파의 종파와 횡파 속도를 측정하기 위하여 기존의 접촉식 초음파 시험법 대신 수침 초음파 시험법을 사용하였다. 통상적으로 수침법에서 종파 에코만 고려하는 것과 달리 모드 변환에 의한 횡파 에코를 찾아서 횡파 속도를 측정하였다. 물질의 두께를 알 수 없어 종파와 횡파 속도를 구할 수 없는 경우에도 두 속도의 비를 이용하여 포아송비를 구할 수 있었다. 다양한 재료를 대상으로 이 방법을 적용한 결과, 속도가 빠른 재료이거나, 포아송비가 작을수록 수침법에 의해 측정한 값이 정확하여 이러한 특징을 가진 세라믹이나 고강도 재료가 이 방법을 통한 종파와 횡파 속도 측정에 적당함을 알 수 있었다.

• 한국전자통신학회논문지
• /
• 제9권3호
• /
• pp.297-302
• /
• 2014

증강현실이란 실세계의 오브젝트에 가상의 오브젝트를 증강시키는 기술로 현실세계에 디지털 정보를 시각화 해주는 기능을 한다. 또한, 증강현실은 실세계와 가상세계를 실시간으로 결합함과 동시에 사용자와 컴퓨터간 상호작용하도록 함으로써 사용자에게 정보전달은 물론 지각능력에 도움을 주며 사용자의 몰입감을 높여주는 기술이라고 할 수 있다. 본 논문에서는 VRML로 모델링된 3차원 객체를 프로그래밍을 통해 3차원 데이터가 증강되는 컨텐츠를 개발하였다. 또한, 가상물체들의 조합을 통해 3차원 아바타 및 다양한 가상의 의상들을 증강시키는 응용기술을 제안하였다. 게다가, 사용자가 직접 마커를 움직여 컴퓨터와 사용자간의 상호작용이 가능한 인터페이스를 제시하여 사용자의 몰입감을 증대 시킬 수 있었다.