• Journal of the Korean Crystal Growth and Crystal Technology
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• v.30 no.6
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• pp.251-257
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• 2020

In order to quickly and clearly recognize characters or images through display glass, glare of the glass must be suppressed. In this study, we tried to reduce glare by analyzing changes in glass surface shape and optical properties through etching process. The etching process was performed as a function of concentrations of the etching solutions, BOE and HF. During the etching process, a compound containing F ion was generated on the surface of the glass, forming an irregular pattern in the form of a projection, and thus various optical properties of the glass were changed; reflectance of 2.5~4.6 %, haze of 4.5~6.6 %, transmittance of 77~92 %, and gloss of 82~107 GU. As a result, optimum etching condition was obtained to minimize the loss of other optical properties while suppressing glare of the glass.

• English & American cultural studies
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• v.16 no.2
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• pp.47-70
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• 2016

Under the inhumane oppression of imperialism, the Third World's political violence has been often represented as an immediate and explosive one with an instant, concentrated visibility. Yet the ecological and psychological exploitation of the Third-World countries by empires, as Rob Nixon insists, shows the relative invisibility of slow violence. This paper is to reveal this slow violence of the marginalized areas symbolized as the lowland. Although Arne Naess' deep ecology promotes the inherent worth of living beings regardless of their instrumental utility to human needs. this paper deals with three postcolonial ecological textbooks which criticize the white-centered deep ecology: Amitav Ghosh's The Glass Palace, Jhumpa Lahiri's The Lowland, and Barbara Kingsolver's The Poisonwood Bible. Through postcolonial critical study, this paper finds out that all these three works have some themes in common. First, these postcolonial works assume a shape of family saga which is parallel to the slow violence of ecological and psychological plundering of empires in the postcolonial countries. Second, like the mangroves which have a tenacious hold on life, these postcolonial people rather overcome the heterogenic challenge with the sturdy and tough mind than defeated. Third, the native people's ethics of earth functions as the stronghold for their respectable lifestyle in their indigenous historicity. Finally, as a big fat brother, the Americanized globalization or neoliberalism is warned as the neocolonialism which is often shown as the disguised pattern of greenwashing. Namely, the people's self-enhancement is always prior to the imperialistic development or neoliberalism in the postcolonial ecological texts which sharply contrast the native's life consciousness and the empire's development theory.

• Journal of the Korean institute of surface engineering
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• v.54 no.3
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• pp.144-151
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• 2021

In the present work, planar-type ZnO powder of [0001] plane with a high aspect ratio range of 20:1 to 50:1 was synthesized. Ag or CuO could be coated on the planar-type ZnO powder by wet methods such as centrifugation or ball milling. During the coating, the average size of the powder was slightly increased while maintaining the shape and XRD pattern of ZnO. When Ag or CuO was coated, the absolute value of the zeta potential, as well as the concentration of oxygen vacancy, was increased. Ag or CuO coated planar-type ZnO power exhibited excellent antibacterial performance, which seems to be related to their high electrostatic attraction force. They could be made into a masterbatch by mixing with ABS resin, and their applicability to antibacterial substances was confirmed by manufacturing the caps of a keyboard.

• Journal of Periodontal and Implant Science
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• v.51 no.1
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• pp.40-52
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• 2021

Purpose: Various crosslinking methods have been introduced to increase the longevity of collagen membranes. The aim of this study was to compare and evaluate the degradation and bone regeneration patterns of 3 collagen membranes. Methods: Four 8-mm-diameter circular bone defects were created in the calvaria of 10 rabbits. In each rabbit, each defect was randomly allocated to 1) the sham control group, 2) the non-crosslinked collagen sponge (NS) group, 3) the chemically crosslinked collagen membrane (CCM) group, or 4) the biphasic calcium phosphate (BCP)-supplemented ultraviolet (UV)-crosslinked collagen membrane (UVM) group. Each defect was covered with the allocated membrane without any graft material. Rabbits were sacrificed at either 2 or 8 weeks post-surgery, and radiographic and histologic analyses were done. Results: New bone formed underneath the membrane in defects in the CCM and UVM groups, with a distinctive new bone formation pattern, while new bone formed from the base of the defect in the NS and control groups. The CCM maintained its shape until 8 weeks, while the UVM and NS were fully degraded at 8 weeks; simultaneously, sustained inflammatory infiltration was found in the margin of the CCM, while it was absent in the UVM. In conclusion, the CCM showed longer longevity than the UVM, but was accompanied by higher levels of inflammation. Conclusions: Both the CCM and UVM showed distinctive patterns of enhancement in new bone formation in the early phase. UV crosslinking can be a biocompatible alternative to chemical crosslinking.

• Journal of Korea Water Resources Association
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• v.55 no.1
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• pp.59-70
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• 2022

Water distribution systems (WDSs) are a representative infrastructure injecting chlorine to disinfect the pathogenic microorganisms and supplying water from sources to consumers. Also, WDSs prescribe to maintain the usual standard (0.1-4.0 mg/L) of residual chlorine. However, the user's usage pattern, water age, network shape, and type affect the hydraulic features (i.e. nodal pressure, pipe velocity) and water quality features (i.e., the residual chlorine concentration). Therefore, this study developed an optimization approach for optimizing WDSs considering water quality-hydraulic factors using Multi-objective Harmony Search (MOHS). The design cost and the system resilience were applied as the design objective functions, and the nodal pressure and the concentration of residual chlorine are used as constraints. The derived optimal designs through this approach were analyzed according to network characteristics such as the network shapes and type. These optimal designs can meet the safety of economic and water quality aspects to increase user acceptance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.6
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• pp.859-864
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• 2022

Drowsy driving, one of the biggest causes of traffic accidents every year, is accompanied by various factors. As a general method to check whether or not there is drowsiness, a method of identifying a driver's expression and driving pattern, and a method of analyzing bio-signals are being studied. This paper proposes a driver fatigue detection system using deep learning technology and bio-signal measurement technology. As the first step in the proposed method, deep learning is used to detect the driver's eye shape, yawning presence, and body movement to detect drowsiness. In the second stage, it was designed to increase the accuracy of the system by identifying the driver's fatigue state using the pulse wave signal and body temperature. As a result of the experiment, it was possible to reliably determine the driver's drowsiness and fatigue in real-time images.

• Journal of The Korean Astronomical Society
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• v.54 no.2
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• pp.61-70
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• 2021

We investigate 20 post-coronal mass ejection (CME) blobs formed in the post-CME current sheet (CS) that were observed by K-Cor on 2017 September 10. By visual inspection of the trajectories and projected speed variations of each blob, we find that all blobs except one show irregular "zigzag" trajectories resembling transverse oscillatory motions along the CS, and have at least one oscillatory pattern in their instantaneous radial speeds. Their oscillation periods are ranging from 30 to 91 s and their speed amplitudes from 128 to 902 km s-1. Among 19 blobs, 10 blobs have experienced at least two cycles of radial speed oscillations with different speed amplitudes and periods, while 9 blobs undergo one oscillation cycle. To examine whether or not the apparent speed oscillations can be explained by vortex shedding, we estimate the quantitative parameter of vortex shedding, the Strouhal number, by using the observed lateral widths, linear speeds, and oscillation periods of the blobs. We then compare our estimates with theoretical and experimental results from MHD simulations and fluid dynamic experiments. We find that the observed Strouhal numbers range from 0.2 to 2.1, consistent with those (0.15-3.0) from fluid dynamic experiments of bluff spheres, while they are higher than those (0.15-0.25) from MHD simulations of cylindrical shapes. We thus find that blobs formed in a post-CME CS undergo kinematic oscillations caused by fluid dynamic vortex shedding. The vortex shedding is driven by the interaction of the outward-moving blob having a bluff spherical shape with the background plasma in the post-CME CS.

• Journal of the Society of Disaster Information
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• v.17 no.4
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• pp.839-847
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• 2021

Purpose: This study investigates mechanical behavior of functionally graded (FG) carbon nanotube-reinforced composite (CNTRC) plate in flexure. Isogeometric analysis (IGA) method coupled with shear deformable theory of higher-order (HSDT) to analyze the nonlinear bending response is presented. Method: Shear deformable plate theory into which a polynomial shear shape function and the von Karman type geometric nonlinearity are incorporated is used to derive the nonlinear equations of equilibrium for FG-CNTRC plate in bending. The modified Newton-Raphson iteration is adopted to solve the system equations. Result: The dispersion pattern of carbon nanotubes, plate geometric parameter and boundary condition have significant effects on the nonlinear flexural behavior of FG-CNTRC plate. Conclusion: The proposed IGA method coupled with the HSDT can successfully predict the flexural behavior of FG-CNTRC plate.

• Journal of Korean Medical classics
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• v.35 no.3
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• pp.41-58
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• 2022

Objectives : In this paper, the outline and overall content of the Majinhwiseong, a specialized medical text on measles written by Lee Wonpung was introduced, along with its academic historical meaning. Methods : The entire Majinhwiseong was analyzed according to content and form. In terms of form, organization, construction, cited literature, etc., were studied, while in terms of content, diagnosis of disease pattern and treatment formulas were studied. Later, based on cited medical texts and the author's social position, the academic historical meaning of this book was discussed. Results : Through the Majinhwiseong, Lee Wonpung strengthened the credibility of the text by not only providing medical knowledge on measles but listing their sources and comparing and analyzing related contents. In the diagnosis part, Lee focused on the changes in symptom, shape, color, and pulse of measles, discussing in detail its differential diagnostic methods. In the treatment part, while listing numerous formulas suggested by Ming (明) masters, Lee did not leave out treatment experiences of Joseon physicians. Meanwhile, the Majinhwiseong is indicative of measles medicine in 18th century Joseon having been progressed in the private sector rather than the official, and how the results of private sector medicine were being absorbed into the official realm through the Uiyakdongcham (議藥同參) system. Conclusions : The Majinhwiseong is a practical treatment manual written by clinician Lee Wonpung to deal measles which was widely spread at the time. The author organized existing medical knowledge on measles for clinicians while reflecting outcomes and medical situation of Joseon physicians in this book. Based on these findings, we could verify that medicine in 18th century Joseon had been progressing actively around the private medical sector.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.3
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• pp.241-248
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• 1991

A few Korean native rice cultivars, 'Sharei' and red rice which are regarded as weedy rice and a rice sample enshrined in the Buddha's Image were examined for the grain shape, seed coat color, amylose content, alkali digestibility and esterase response pattern. Among the Korean native varieties which are collected during 1920's and preserved up to now, there are some varieties belong to the typical Indicas. Some lines of 'Sharei' and some collections of red rice from farmer's field showed the evidence of Indica rice. A rice sample which was enshrined in the Buddha's image in 1302 looked like a mixtures of Indica and Japonica. Reviewing the articles from the old books describing characteristics and some reports on the Indica rice in Korea, it was deduced that the Indica rice was grown in Korea in some extent before 1300.