• Journal of the Microelectronics and Packaging Society
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• v.29 no.1
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• pp.7-16
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• 2022

Recently, the automobile industry is rapidly changing due to technological development. Next-generation cars with high technology and new functions are on the market. It is essential to develop electronic devices to meet the condition of next-generation cars. In this study, the authors have reviewed recent trends of automotive electronics and packaging technology. Automotive electronics are used in harsh environments compared with other industries. Thus, it is important to improve the reliability of device junctions that directly affect electronics performance. Soldering, TLP (transient liquid phase bonding), and sintering are introduced for the bonding methods in car electronics.

• Membrane Journal
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• v.31 no.6
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• pp.456-470
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• 2021

In this study, polyetherimide-based hollow fiber membranes were manufactured using the NIPS (nonsolvent induced phase separation) method. THF, Ethanol, and LiNO₃ were used as additives to control the morphology of the PEI-hollow fiber membranes. Furthermore, for the development of a high hydrogen separation membrane, the spinning conditions were optimized through the characterization of SEM and gas permeance. As a result, as the content of THF increased, the hydrogen/carbon dioxide selectivity increased. However, the permeance decreased due to the trade-off relationship. When ethanol was added, a finger-like structure was shown, and when LiNO₃ was added, a sponge structure was shown. In particular, in the case of a hollow fiber membrane with an optimized PDMS coating layer, the permeance was 40 GPU and the hydrogen/carbon dioxide selectivity was 5.6.

• Journal of dental hygiene science
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• v.21 no.4
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• pp.219-226
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• 2021

Background: Proper detection and management of dental plaque are essential for individual oral health. We aimed to evaluate the maturation level of dental plaque using a two-tone disclosing agent and to compare it with the fluorescence of dental plaque on the quantitative light-induced fluorescence (QLF) image to obtain primary data for the development of a new dental plaque scoring system. Methods: Twenty-eight subjects who consented to participate after understanding the purpose of the study were screened. The images of the anterior teeth were obtained using the QLF device. Subsequently, dental plaque was stained with a two-tone disclosing solution and a photograph was obtained with a digital single-lens reflex (DSLR) camera. The staining scores were assigned as follows: 0 for no staining, 1 for pink staining, and 2 for blue staining. The marked points on the DSLR images were selected for RGB color analysis. The relationship between dental plaque maturation and the red/green (R/G) ratio was evaluated using Spearman's rank correlation. Additionally, different red fluorescence values according to dental plaque accumulation were assessed using one-way analysis of variance followed by Scheffe's post-hoc test to identify statistically significant differences between the groups. Results: A comparison of the intensity of red fluorescence according to the maturation of the two-tone stained dental plaque confirmed that R/G ratio was higher in the QLF images with dental plaque maturation (p<0.001). Correlation analysis between the stained dental plaque and the red fluorescence intensity in the QLF image confirmed an excellent positive correlation (p<0.001). Conclusion: A new plaque scoring system can be developed based on the results of the present study. In addition, these study results may also help in dental plaque management in the clinical setting.

• Journal of the Korean Electrochemical Society
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• v.25 no.2
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• pp.69-80
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• 2022

The anion exchange membrane (AEM) water electrolysis for high purity hydrogen production is attracting attention as a next-generation green hydrogen production technology by using inexpensive non-noble metal-based catalysts instead of conventional precious metal catalysts used in proton exchange membrane (PEM) water electrolysis systems. However, since AEM water electrolysis technology is in the early stages of development, it is necessary to develop research on AEM, ionomers, electrode supports and catalysts, which are key elements of AEM water electrolysis. Among them, current research in the field of catalysts is being studied to apply a previously developed half-cell catalyst for alkali to the AEM system, and the applied catalyst has disadvantages of low activity and durability. Therefore, this review presented a catalyst synthesis technique that promoted oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) using a non-noble metal-based catalyst in an alkaline medium.

• Journal of the Korea Safety Management & Science
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• v.24 no.4
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• pp.49-59
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• 2022

Mt. Umyeon is a low-altitude mountain near a residential area, and the actual forest area is not large due to the fact that development for use as a living green space is being completed and in progress across the mountain, so the buffering action for landslides was weak. The unit was located at the top of Mt. Umyeon, and there were reports of contents related to the military unit in some accident areas. Some experts suggested that the landslide that started on the cut side of the unit could be one of the causes of the landslide at Mt. Umyeon. It is presumed that there was a sudden collapse of trees that had fallen due to erosion inside the valley. In the case of the Umyeon landslide, localized torrential rain is the biggest cause, but the fact that it suffered a lot of damage is the result of no preemptive measures. In particular, it can be said that the damage was caused by the concentration of residential and commercial facilities due to the unplanned urban expansion without prior review of the feng shui geography of settlement areas. The important lesson we have learned is that we should recognize nature as living things and live in harmony and coexistence between humans and nature through understanding and cooperation. Adapting to changes in the environment can survive, but if it doesn't, it will be slaughtered. As such, geography influences changes in feng shui. Changes in feng shui have a profound effect on not only humans but also the natural ecosystem.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.4
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• pp.577-583
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• 2022

In this study, the characteristics of self-healing mortars produced using an inorganic self-healing material consisting of ground granulated blast furnace slag, expansion agent, and anhydrite, were investigated. For three types of self-healing mortars with different amounts of the inorganic healing material, compressive strength was measured and the self-healing performance was evaluated through the constant water head permeability test. The healing rate and equivalent crack width according to crack-induced aging were used as indicies of healing performance evaluation. Considering the development of compressive strength of the self-healing mortars, the change in the healing rate with healing periods, and the economic feasibility, the optimal amount of inorganic self-healing materials was suggested as 20 % of the mass of cement.

• The Plant Pathology Journal
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• v.38 no.6
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• pp.583-592
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• 2022

Root-knot nematode disease is a widespread and catastrophic disease of tobacco. However, little is known about the relationship between rhizosphere bacterial community and root-knot nematode disease. This study used 16S rRNA gene sequencing and PICRUSt to assess bacterial community structure and function changes in rhizosphere soil from Meloidogyne incognita-infected tobacco plants. We studied the rhizosphere bacterial community structure of M. incognita-infected and uninfected tobacco plants through a paired comparison design in two regions of tobacco planting area, Yuxi and Jiuxiang of Yunnan Province, southwest China. According to the findings, M. incognita infection can alter the bacterial population in the soil. Uninfested soil has more operational taxonomic unit numbers and richness than infested soil. Principal Coordinate Analysis revealed clear separations between bacterial communities from infested and uninfested soil, indicating that different infection conditions resulted in significantly different bacterial community structures in soils. Firmicutes was prevalent in infested soil, but Chloroflexi and Acidobacteria were prevalent in uninfested soil. Sphingomonas, Streptomyces, and Bradyrhizobium were the dominant bacteria genera, and their abundance were higher in infested soil. By PICRUSt analysis, some metabolism-related functions and signal transduction functions of the rhizosphere bacterial community in the M. incognita infection-tobacco plants had a higher relative abundance than those uninfected. As a result, rhizosphere soils from tobacco plants infected with M. incognita showed considerable bacterial community structure and function alterations.

• Journal of Species Research
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• v.11 no.4
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• pp.266-277
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• 2022

The current surveys of Ulva in the subtidal area around Jeju Island give a chance to discover unrecorded green algal species of the Korean macroalgal flora. As a result of this investigation, we found Ulva adhaerens Matusmoto & Shimada, inhabiting the subtidal regions, up to 15 m deep, and conducted the DNA barcoding on plastid rbcL-3P and tufA regions with describing the morphological characteristics. Our specimens of U. adhaerens forms a monophyletic clade with the Japanese type specimen and U. piritoka Ngāti Kuri, Heesch & W.A. Nelson from New Zealand exhibiting each 0.3% sequence divergences, respectively, in the plastid rbcL-3P. The genetic variation of U. adhaerens clade is 1.0-3.9% in rbcL-3P and 4.8-9.8% in tufA to each Ulva species, including the generic type, U. lactuca Linneaus. The morphology of Korean U. adhaerens specimens is identical to the type specimens of U. adhaerens from Japan having the development of rhizoidal filaments from both of the cell layers of the distromatic blade and the extension of rhizoidal clumps with adhesive trait between blades by extended rhizoidal clumps at the basal blades. The thallus attachment to substrate is by numerous minute discoidal plates made up of rhizoids originating from the inner part of distromatic blades in basal. Although there are still some problems to resolve the relationship between U. adhaerens and U. piritoka in the rbcL dataset and the phylogenetic pattern of the Group II intron of rbcL, we propose the new record of U. adhaerens in Korean macroalgal flora based on the morphological characteristics of Korean specimens. Continued study of the genus Ulva by morphological and molecular assessment will delimit the species of Ulva, elucidate the relationships between them, and uncover the species diversity.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.3
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• pp.365-378
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• 2022

Complete blood cell count(CBC) is a technique that counts leukocytes for each type of blood cell being analyzed. The principle is that laser is incident to ex vivo flowing leukocytes in a microcapillary tube and scattered light occurs by laser and leukocytes. By collecting the scattered light, we can count the types of cells because different cells generate different light-scattering patterns. However, the technique has an intrinsic limitation, scattering pattern is shown in a wide range region in the resulting, which makes it difficult to accurate analyze and use fluorescent dyes. To overcome this limitation, a new design of CBC with a dual laser, which irradiates with orthogonal angles for collecting quad-scattering information was proposed. Before development, the scattering difference depending on wavelength must be investigated to only catch up to the scattered signal by angles. Some studies, which focused on simple particles, have been conducted to theoretically and experimentally investigate different scatterings by wavelength. In this study, we propose an optical system for measuring scattered light and investigate a complex particle. As a result, the green laser made strong scattering signals in both the forward and side direction: 10% and 30%, respectively.

• Journal of Digital Convergence
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• v.20 no.5
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• pp.375-381
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• 2022

The DEA-BCC model. And the Malmquist index have been used, from static and dynamic perspectives, to measure the eco-efficiency of 30 cities and provinces in China from 2011 to 2020. The results shows that: the average static eco-efficiency of 30 cities and provinces in China is 0.643. Differences exists all over China. While Shanghai and Beijing are ecologically efficient, other 28 cities and provinces are faced with different extents of inefficiency. There are also differences among regions, which generally show the spatial distribution pattern with high efficiency in the eastern regions while low in the western regions. The Malmquist index of eco-efficiency in total 30 cities and provinces shows a healthy growth trend, and the technological progress. Acts as its main driving force. Therefore, eastern regions should enhance the. radiation capacity, strengthen the synergy among regions, give full play to. The advantages of each regions. It is sensible to improve the eco-efficiency by means of optimizing the industrial structure, enhancing the technological level and improving eco-efficiency of China and realizing green development.