• The Journal of Korea Robotics Society
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• v.14 no.4
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• pp.326-332
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• 2019

In the case of conventional soft robots, the basic stiffness is small due to the use of flexible materials. Therefore, there is a limitation that the load that can bear is limited. In order to overcome these limitations, a study on a variable stiffness method has been conducted. And it can be seen that the jamming mechanism is most effective in increasing the stiffness of the soft robot. However, the jamming mechanism as a method in which a large number of variable act together is not even theoretically analyzed, and there is no study on intrinsic principle. In this paper, a study was carried out to increase the stability of the force chain to increase the stiffness due to the jamming transition phenomenon. Particle size variables, backbone mechanisms were used to analyze the stability of the force chains. We choose a jamming mechanism as a variable stiffness method of a soft robot, and improve the effect of stiffness based on theoretical analysis, modeling FEM simulation, prototyping and experiment.

• Current Optics and Photonics
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• v.3 no.1
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• pp.78-85
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• 2019

The remote phosphor structure has been proven to bear greater luminous efficiency than both the conformal phosphor and in-cup phosphor structures; however, controlling its color quality is much more challenging. To solve this dilemma, various researchers have proposed dual-layer phosphor and triple-layer phosphor configuration as techniques to enhance the display brightness of white LEDs (WLEDs). Likewise, this study picked one of these configurations to utilize in multichip WLEDs with five distinct color temperatures in the range from 5600 to 8500 K, for the purpose of improving the optical properties of WLEDs, such as color rendering index (CRI), color quality scale (CQS), luminous efficacy (LE), and chromatic homogeneity. According to the results of this research, the triple-layer phosphor configuration has superior performance compared to other configurations in terms of CRI, CQS, and LE, and yields higher chromatic stability for WLEDs.

• East Asian Economic Review
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• v.23 no.2
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• pp.149-168
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• 2019

Public information arrivals and their immediate incorporation in asset price is a key component of semi-strong form of the Efficient Market Hypothesis. In this study, we explore the impact of public information arrivals on cryptocurrency market via Twitter posts. The empirical analysis was conducted through various methods including Kapetanios unit root test, Maki cointegration analysis and Markov regime switching regression analysis. Results indicate that while in bull market positive public information arrivals have a positive influence on Ripple's value; in bear market, however, even if the company releases good news, it does not divert out the Ripple from downward trend.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.47.2-47.2
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• 2018

The umbral oscillations of velocity are commonly observed in the chromosphere of a sunspot. Their sources are considered to be either the external p-mode driving or the internal excitation by magnetoconvection. Even though the possibility of the p-mode driving has been often considered, the internal excitation has been rarely investigated. We report the observational evidence for the internal excitation obtained by analyzing velocity oscillations in the temperature minimum region of a sunspot umbra. The velocity oscillations in the temperature minimum region were determined from Fe I $5435{\AA}$ line data taken by the Fast Imaging Solar Spectrograph (FISS) of the 1.6 m Goode solar Telescope (GST) at the Big Bear Solar Observatory. As a result, we discovered 4 events of oscillations which appear to be internally excited. We analyze their characteristics and relation to photospheric features. Based on these results, we estimate the contribution of the internal excitation for umbral oscillations and discuss their importance.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.58.3-59
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• 2018

We investigate velocity oscillations in a solar quiet region by using the spectral data of the $H{\alpha}$ and Ca II $8542{\AA}$ lines. The data were acquired by the Fast Imaging Solar Spectrograph installed at the 1.6 m Goode Solar Telescope of Big Bear Solar Observatory. According to Chae & Litvinenko (2018)'s theoretical work, there is a correlation between dominant period of the oscillations and the temperature of the temperature minimum region in a non-isothermal atmosphere. In our study, we measure the temporal variations of the intensity and the line of sight Doppler velocity, and find out the relations between the intensity and dominant period of the oscillations. In addition, we investigate oscillations in a few distinct regions and discuss regional characteristics of the oscillations.

• Geomechanics and Engineering
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• v.18 no.1
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• pp.1-9
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• 2019

In this study, both 2D and 3D failure shapes of rock mass above the water-filled cavity are put forward when the surrounding rock mass cannot bear the pressure caused by the water-filled cavity. Based on the analytical expressions derived by kinematic approach, the profiles of active and passive failure patterns are plotted. The sensitivity analysis is conducted to explore the influences of different rock parameters on the failure profiles. During the excavation of the deep tunnels above the karst cavity, the water table always changes because of progressive failure of cavity roof. Therefore, it is meaningful to discuss the effects of varying water level on the failure patterns of horizontal rock layers. The changing laws of the scope of the failure pattern obtained in this work show good consistency with the fact, which could be used to provide a guide in engineering.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.47 no.2
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• pp.128-134
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• 2021

Various techniques have been used to reconstruct the temporomandibular joints, including autogenous transplants and alloplastic implants. Among autogenous grafts, costochondral grafts have mainly been used. A costochondral graft has many advantages over other autogenous grafts and alloplastic implants. Harvest is easy and has minimal impact on patients. The graft can bear functional load well and biocompatibility is excellent. A costochondral graft obviates foreign body reactions and further surgery for revision of alloplastic replacements if the graft takes well. Although long-term prognosis remains unclear, it appears that for autogenous condylar reconstruction, costochondral grafts can be used with few complications and acceptable results. This article describes cases and discusses surgical techniques and considerations related to costochondral grafts.

• Bulletin of the Korean Chemical Society
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• v.8 no.4
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• pp.291-296
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• 1987

Vibrational spectroscopy has been applied to the benzenethiol molecule adsorbed on the silver surface. The results of infrared and Raman spectral studies have led to the conclusion that benzenethiol is chemisorbed dissociatively on the silver surface by rupture of S-H bond and the benzenethiolate formed upon adsorption is bound to silver via its sulfur atom. It seemed more likely that benzenethiol is adsorbed as being inclined to the silver surface. On contact with oxygen, the geometry of the adsorbed species appeared to bear a resemblance to that of silver benzenethiolate salt. The infrared bands of adsorbed species remained with little decrease of intensity even after the prolonged evacuation at 673 K, indicating that benzenethiol is very strongly chemisorbred to the silver surface.

• SUVANNABHUMI
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• v.15 no.2
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• pp.245-270
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• 2023

Many publications of ecocritical research papers and translations of ecocriticism occur in Vietnam in recent years. This paper examines ecocritical scholarly writing in Vietnam, understanding how it corresponds to-reflects and attends to-contemporary Vietnamese society and politics. Specifically, this paper contextualizes Vietnamese ecocriticism in contemporary social and political concerns-embodied in journalistic and administrative documents-about the modernity-oriented postcolonial nation-building of Vietnam. In revealing critiques of political and social degenerations implied in ecocritical writings in Vietnam, this paper suggests that the emergence of ecocriticism in present-day Vietnam indicates a recent "political turn." More importantly, such emergence reflects and engages with the continuing Marxist perspective of literature as an instrument for social criticism and cultural revolution in Vietnam. Vietnamese ecocritics bear the mission of prophets of the time, public educators, and soul engineers, writing is an act of engaging with and influencing reality. Writing (literary and scholarly) still forms an idealized ideological instrument in the struggles for national homogeneity and sovereignty and social democracy in present-day Vietnam.

• Progress in Superconductivity and Cryogenics
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• v.11 no.1
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• pp.60-63
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• 2009

Most J-T (Joule-Thomson) refrigerators use a Giaque-Hampson type heat exchanger due to its excellent thermal performance and compactness. The cryoprobe (cryosurgical probe) treating prostate cancer usually has a dimension of 17 gauge (1.6 mm diameter), so it does not have enough space to bear a Giaque-Hampson type heat exchanger. In this paper, the triplet heat exchanger is adopted as the heat exchanger of cryoprobe, and the performance is investigated with an experimental test. The result shows that the triplet heat exchanger can be substituted for Giaque-Hampson type heat exchanger in the application of cryosurgery.