• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.857-860
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• 2000

The objective of this paper is to demonstrate degradation phenomena through DC degradation tests and predicts degradation phenomena as a function of time from the tests. The ZnO varistor used in this investigation were fabricated by standard ceramic techniques. Especial, these were sintered in nitrogen atmosphere, at 2 h, for $1300^{\circ}C$. The conditions of DC degradation test were 115$\pm$$2^{\circ}C$for 0, 2, 4, and 8 h, respectively. To demonstrate the degradation phenomena of ZnO varistors, Voltagecurrent analyses were performed before and after the degradation test, and frequency analyses were used with the time of the degradation tests. It was found that the degradation occurred in not grain but grain boundary and the degradation behavior of varistors was unsymmetrically degraded with the direction of tests.

• Journal of the Korean Ceramic Society
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• 제40권11호
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• pp.1047-1057
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• 2003

A sub-nanometer resolution Scanning Nonlinear Dielectric Microscope (SNDM) was developed for observing ferroelectric polarization. We also demonstrate that the resolution of SNDM is higher than that of a conventional piezo-response imaging. Secondly, we report new SNDM technique detecting higher nonlinear dielectric constants $\varepsilon$$\_$3333/ and $\varepsilon$$\_$33333/. Higher order nonlinear dielectric imaging provides higher lateral and depth resolution. Finally, the formation of artificial small inverted domain is reported to demonstrate that SNDM system is very useful as a nano-domain engineering tool. The nano-size domain dots were successfully formed in LiTaO$_3$ single crystal. This means that we can obtain a very high density ferroelectric data storage with the density above 1T-bits/inch$^2$.

• The Journal of Korea Robotics Society
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• 제12권1호
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• pp.78-85
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• 2017

This paper presents the development of a 3D printer based piezo-driven vertical micro-positioning stage. The stage consists of two flexure bridge structures which amplify and transfer the horizontal motion of the piezo-element into vertical motion of the end-effector. The stage is fabricated with ABS material using a precision 3D printer. This enables a one-body design eliminating the need for assembly, and significantly increases the freedom in design while shortening fabrication time. The design of the stage was optimized using response surface analysis method. Experimental results are presented which demonstrate 100nm stepping in the vertical out-of-plane direction. The results demonstrate the future possibilities of applying 3D printers and ABS material in fabricating linear driven motion stages.

• Magazine of the Korean Society of Agricultural Engineers
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• 제7권1호
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• pp.843-849
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• 1965

Some simple devices to demonstrate important hydraulic principles to students are necessitated in fluid mechanics or hydraulics classes. These devices should\ulcorner be easy to make and operate with inexpensive cost. The writer has studied some simple demonstrhation apparatus of hydraulic principles which were made with cheap materials. The purpose of this paper is to present the results of the study. In this paper, hydraulic principles that can be demonstrated by using these apparatus are described, the plans of them are presented, and how to make them and what materiaIs to be used are briefly explained. An axial-flow fan is a device with which the flow of air is supplied for several purposes. It consists of a duct, a fan and a guide vane. It may be possible to demonstrate the principles of propeIler,drag force, lift, etc.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 한국화재소방학회 1997년도 International Symposium on Fire Science and Technology
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• pp.472-476
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• 1997

Hot-smoke testing in Australia has progressed to the stage where there is an Australian Standard for these tests. The purpose of such tests is twofold: firstly they can validate computer modeling predictions for smoke movement, and secondly they can demonstrate that the smoke control systems and associated fire safety systems function satisfactorily. Hot-smoke tests were carried out in March 1997 at two of Sydney's underground railway stations, namely St James and Museum. The purpose of the tests was to demonstrate that the smoke control systems performed their functions as intended. Tests were carried out in the concourses and on the platforms, and trains ran during the tests so that the effect of moving trains on smoke movement could be observed. A total of five tests were carried out and video recordings were taken of each. This is the first time that hot-smoke tests have been carried out in an underground station with trains running. The paper discusses some of the interesting observations and the problems identified by the tests.

• Molecules and Cells
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• 제41권12호
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• pp.1045-1051
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• 2018

The developmentally regulated GTP binding protein 2 (DRG2) is involved in the control of cell growth and differentiation. Here, we demonstrate that DRG2 regulates microtubule dynamics in HeLa cells. Analysis of live imaging of the plus-ends of microtubules with EB1-EGFP showed that DRG2 deficiency (shDRG2) significantly reduced the growth rate of HeLa cells. Depletion of DRG2 increased 'slow and long-lived' subpopulations, but decreased 'fast and short-lived' subpopulations of microtubules. Microtubule polymerization inhibitor exhibited a reduced response in shDRG2 cells. Using immunoprecipitation, we show that DRG2 interacts with tau, which regulates microtubule polymerization. Collectively, these data demonstrate that DRG2 may aid in affecting microtubule dynamics in HeLa cells.

• Nuclear Engineering and Technology
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• 제50권8호
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• pp.1372-1386
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• 2018

Despite recent advances in multi-hazard analysis, the complexity and inherent nature of such problems make quantification of the landslide effect in a probabilistic safety assessment (PSA) of NPPs challenging. Therefore, in this paper, a practical approach was presented for performing an earthquake-induced landslide PSA for NPPs subject to seismic hazard. To demonstrate the effectiveness of the proposed approach, it was applied to Korean typical NPP in Korea as a numerical example. The assessment result revealed the quantitative probabilistic effects of peripheral slope failure and subsequent run-out effect on the risk of core damage frequency (CDF) of a NPP during the earthquake event. Parametric studies were conducted to demonstrate how parameters for slope, and physical relation between the slope and NPP, changed the CDF risk of the NPP. Finally, based on these results, the effective strategies were suggested to mitigate the CDF risk to the NPP resulting from the vulnerabilities inherent in adjacent slopes. The proposed approach can be expected to provide an effective framework for performing the earthquake-induced landslide PSA and decision support to increase NPP safety.

• International Journal of Internet, Broadcasting and Communication
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• 제13권4호
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• pp.48-54
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• 2021

In most existing researches on non-orthogonal multiple access (NOMA) with symmetric superposition coding (SSC), uniform sources have been usually considered. For the first part in this two-part paper, for the strongest channel gain user, we showed that the bit-error rate (BER) for the optimal maximum a-posteriori (MAP) receiver for the non-uniform source improves slightly, compared to that of the conventional receiver for the uniform sources. We demonstrate that in communication scenarios of the non-uniform source NOMA schemes, for the weakest channel gain user, the BER performance of the optimal MAP receiver for a non-uniform source improves greatly, compared to that of the conventional receiver for uniform sources. We first derive an analytical expression of the BER for non-uniform source NOMA with SSC. Then, simulations demonstrate that the BER of the optimal MAP receiver for the non-uniform source improves, compared with that of the conventional maximum likelihood (ML) receiver for the uniform sources. In result, the proposed optimal MAP receiver for the non-uniform source could be a promising scheme for SSC NOMA, with improved BER performances.

• Journal of Industrial and Engineering Chemistry
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• 제67권
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• pp.231-235
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• 2018

In this study, we demonstrate the conversion of starch to (R,R)-2,3-butanediol (2,3-BD) in a hybrid cell-free synthesis system containing a mixture of lysates derived from Escherichia coli (E. coli) and cyanobacteria. A sufficient pool of pyruvate required for the synthesis of 2,3-BD was generated by combining metabolic pathways of cyanobacteria and E. coli. Successful synthesis of 2,3-BD was achieved by additional modifications of the hybrid cell-free system with the enzymes required to convert pyruvate to 2,3-BD. The results demonstrate a new approach to harness biological pathways to expand the scope of cell-free metabolic engineering by cross-species combinations of cell lysates.

• Asia Marketing Journal
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• 제25권1호
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• pp.26-36
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• 2023

This study examines the effects of disclosing sales commissions pertaining to an influencer discount code on perceived sincerity of an influencer and attitude toward using the discount code. In Study 1, consumers participated in a two-cell (commission disclosure: absent vs. present) between-subjects experimental design. In Study 2, consumers participated in a two (commission disclosure: absent vs. present) by two (discount level: low vs. high) between-subjects experimental design. The findings of Study 1 demonstrate that the sales commission disclosure pertaining to discount codes results in a higher perceived sincerity of the influencer. The results of Study 1 also reveal that the perceived sincerity of the influencer mediates the effect of the disclosure (vs. no disclosure) on attitude toward using the discount code. Further, the findings of Study 2 demonstrate the robustness of these disclosure effects regardless of whether the discount level is low or high.