• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.5
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• pp.9-15
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• 2022

Discarded bio-wastes, such as seeds and rinds, cause environmental problems. Multiple studies have recycled bio-wastes as eco-friendly energy sources to solve these problems. This study uses bio-waste to fabricate a mandarin peel powder based triboelectric nanogenerator (MPP-TENG). The MPP-TENG is based on the contact separation mode. It generates an open-circuit voltage and short-circuit current of 156V and 2µA, respectively. In addition, MPP-TENG shows stable operation over continuous 3000s without any deviation in output. Also, the device exhibits maximum power density of 5.3㎼/cm² when connected to a resistance of 100MΩ. In an energy storage capacity test for 1000s, the MPP-TENG stores an energy of 171.6µJ in a 4.7µF capacitor. The MPP-TENG can power 9 blue LEDs and 54 green lettering LEDs. These results confirm that the MPP-TENG can provide a new avenue for eco-friendly energy harvesting device fabrication.

• Asia-Pacific Journal of Business
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• v.12 no.2
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• pp.175-186
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• 2021

Purpose - This study intended to identify the effects of varied institutional systems and policies that regulate or define operations of enterprises upon the profitability of private enterprises through case analysis. Design/methodology/approach - The systems and differences in the institution and commodity distribution in Korea and Japan, which define the operation of the "Garak Wholesale Market" and "Ota Wholesale Market". We were examined in the presentthis study, and the statistical data pertinent to the trade volume and profitability of wholesale market corporations that substantially run both markets, were analyzed. Findings - The competition among the corporations that run the "Garak Wholesale Market" substantially is limited due to regulations over the mode of transaction and monopoly of trust thereby significantly higher level of profitability and safety are guaranteed. However, the institutional autonomy that enabled each distributor in the "Ota Wholesale Market" to compete with each other freely caused the distributors therein face difficulties in securing stable profits due to the relatively poor level of profitability resulted from the autonomy. Research implications or Originality - It seems the autonomy in commercial transaction in the "Garak Wholesale Market" in Korea needs to be secured to promote the competition of distributors therein through an amelioration of institutional systems and amendment of relevant laws that prescribe current management of various distributors/operators in the market.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.58 no.3
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• pp.230-240
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• 2022

In general, a high tension on the anchor and chain is placed when a ship at anchor is subjected to heavy weather. Mariners have to pay attention to whether dragging anchor occurs to keep the safety of the ship at anchorage since it is difficult to maintain the stable motion of ship and it causes collisions with other ships nearby. In this paper, the ship motion against the external forces was shown to obtain the fundamental data about characteristic of holding power due to nature of seabed at anchor, so practical trials were carried out in rocky area and muddy area using a trial ship around coastal area of South Korea. In muddy seabed, holding power showed reasonable tension values depending on the distance from anchor position of continuing swing motions of a ship corresponding to wind force. Meanwhile in rocky seabed, tension values on the chain appeared very high occasionally regardless of the distance from the anchor position and seemed to exceed its holding power to be the breaking strain of the chain although weather was not in a severe condition. Therefore, some of the cables laid on the seabed were presumed to be caught in a crack on the rock. It is assumed that even a small amount of external force may cause the chain to break in a moment in rocky seabed. Additionally, wind and current forces had a somewhat contradictory effect on holding power of the ship between them.

• International Journal of Computer Science & Network Security
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• v.22 no.8
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• pp.269-274
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• 2022

Economy of Ukraine is characterized by the rapidly increased level of financial failures at a corporate level. Conditions of doing business in Ukraine become tighter year after year and it should motivate the business owners not only to watch more accurately the state in which their business is but also to introduce new, more precise, more tight systems of crisis management and economic security. The experience shows that in order to stay afloat and not to suffer losses companies should pay more attention to different areas of economic security, such as production potential, financial indicators, logistics, staff, etc. For this purpose companies should use a system of valuation of the most important for their activity indicators and transform their values in an integral one in order to use this assessment in making managerial decisions. Such a valuation is one of the components which the article presents. The article also reveals the key points which characterize crisis management as an integral part of enterprise development and economic security. There are specified the essence and problems of crisis management and proposed the ways of raising the level of economic security of a company based on the example of an industrial and commercial enterprise. The key focus of the enterprise's economic security management is defined as constructive responses to threats from the external environment and, as a result, ensuring stable functioning and effective realization of untapped potential in the future. The current assumption is to explain the scheme of strategic management of an industrial and commercial enterprise and to calculate the methodology of an express assessment of the level of enterprise economic security, taking into account the components of crisis management. To assess the level of economic security of the enterprise, it is proposed to use the method of point assessment, which is based on a multi-level system of indicators, which covers the main areas of the enterprise's activity.

• ALGAE
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• v.37 no.2
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• pp.123-133
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• 2022

Genetic diversity and distribution patterns of marine macroalgae are increasingly being documented in Southeast Asia. These studies show that there can be significant levels of genetic diversity and isolation between populations on either side of the Thai-Malay Peninsula. Bostrychia tenellla is a common filamentous red seaweed in the region and the entity is represented by at least two cryptic species. Despite being highly diverse and widespread, genetic variation and population structure of this species complex remains understudied, especially around the Thai-Malay Peninsula. We analyzed genetic diversity and inferred the phylogeographic pattern of specimens identified as B. tenella using the plastid RuBisCo spacer from samples from the Andaman Sea and the Gulf of Thailand. Our genetic analysis confirmed the occurrence of the two cryptic B. tenella species (B and C) along both coasts. Cryptic species B was more common in the area and displayed higher genetic diversity than species C. Historical demographic analyses indicated a stable population for species B, but more recent population expansion for species C. Our analyses also revealed that both cryptic species from the Andaman Sea possessed higher genetic diversity than those of the Gulf of Thailand. We also detected moderate to high levels of gene flow and weak phylogeographic structure of cryptic species B between the two coasts. In contrast, phylogeographic analysis showed genetic differences between populations of both cryptic species within the Andaman Sea. Overall, these results suggest that cryptic B. tenella species around Thai-Malay Peninsula may have undergone different demography histories, and their patterns of genetic diversity and phylogeography were likely caused by geological history and regional sea surface current circulation in the area.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2001.06a
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• pp.72-72
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• 2001

Plasma polymerized thin films have been deposited on Si(lOO) substrates at $25-400^{\circ}C$ using thiophene ($C_4H_4S$) precursor by plasma assisted chemical vapor deposition (PACVD) method for low-dielectric device application. In order to compare physical properties of the as-grown thin films, the effects of the plasma power, gas flow ratio and deposition temperature on the dielectric constant and thermal stability were mainly studied. XRD and TED studies revealed that the as-grown thin films have highly oriented amorphous polymer structure. XPS data showed that the polymerized thin films that grown under different RF power and deposition temperature as well as different gas ratio of $Ar:H_2$ have different stoichiometric ratio of C and S compared with that of monomer, indicating a formation of mixture polymers. Moreover, we also realized that oxygen free and thermally stable polymer thin films could be grown at even $400^{\circ}C$. The results of SEM, AFM and TEM showed that the polymer films with smooth surface and sharp interface could be grown under various deposition conditions. From the electrical property measurements such as I-V and C-V characteristics, the minimum dielectric constant and the best leakage current were obtained to be about 3.22 and $10-11{\;}A/\textrm{cm}^2$, respectively.

• Steel and Composite Structures
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• v.47 no.2
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• pp.269-287
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• 2023

The WGJ420 fire-resistant weathering (FRW) steel is developed and manufactured with standard yield strength of 420 MPa at room temperature, which is expected to significantly enhance the performance of steel structures with excellent fire and corrosion resistances, strong seismic capacity, high strength and ductility, good resilience and robustness. In this paper, the mechanical properties of FRW steel plates and buckling behavior of columns are investigated through tests at elevated temperatures. The stress-strain curves, mechanical properties of FRW steel such as modulus of elasticity, proof strength, tensile strength, as well as corresponding reduction factors are obtained and discussed. The recommended constitutive model based on the Ramberg-Osgood relationship, as well as the relevant formulas for mechanical properties are proposed, which provide fundamental mechanical parameters and references. A total of 12 FRW steel welded I-section columns with different slenderness ratios and buckling load ratios are tested under standard fire to understand the global buckling behavior in-depth. The influences of boundary conditions on the buckling failure modes as well as the critical temperatures are also investigated. In addition, the temperature distributions at different sections/locations of the columns are obtained. It is found that the buckling deformation curve can be divided into four stages: initial expansion stage, stable stage, compression stage and failure stage. The fire test results concluded that the residual buckling capacities of FRW steel columns are substantially higher than the conventional steel columns at elevated temperatures. Furthermore, the numerical results show good agreement with the fire test results in terms of the critical temperature and maximum axial elongation. Finally, the critical temperatures between the numerical results and various code/standard curves (GB 51249, Eurocode 3, AS 4100, BS 5950 and AISC) are compared and verified both in the buckling resistance domain and in the temperature domain. It is demonstrated that the FRW steel columns have sufficient safety redundancy for fire resistance when they are designed according to current codes or standards.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2002.02a
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• pp.339-339
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• 2002

In the RABiTS approach to coated conductor development, successful (both economic and technological) depends on the refinement and optimization of each of three important components: the metal tape substrate, the buffer layer(s), and the HTS layer. Here we will report on the ORNL approach and progress in each of these areas. - Most applications will require metal tapes with low magnetic hysteresis, mechanical strength, and excellent crystalline texture. Some of these requirements are competing. We report on progress in obtaining a good combination of these characteristics on metal alloys of Ni-Cr and Ni-W. - The deposition of appropriate buffer layers is a crucial step. Recently, base research has shown that the presence of a stable sulfur superstructure present on the metal surface is needed for the nucleation and epitaxial growth of vapor-deposited seed buffer layers such as YSZ, CeO$_2$ and SrTiO$_3$. We report on the details and control of this superstructure for nickel tapes, as well as recent results for Cu and Ni-13%Cr. - Processes for deposition of the HTS coating must economically provide large values of the figure-of-merit for conductors, current x length. At ORNL, we have devoted efforts to a precursor/post-annealing approach to YBCO coatings, for which the deposition and reaction steps are separate. We describe motivation for and progress toward developing this approach. - Finally, we address some issues for the implementation of coated conductors in real applications, including the need for texture control and electrical stabilization of the HTS coating.

• The Journal of the Convergence on Culture Technology
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• v.9 no.1
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• pp.401-405
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• 2023

From a phenomenological perspective on military human resources to carry out the government's "Defense Vision 2050" project, this study presents the direction of revision of the military pension along with the age and continuous retirement age system under Article 8 of the Military Personnel Act and the promotion criteria under Article 33 of the Enforcement Decree of the Military Act. The Military Personnel Act and the Enforcement Decree of the Military Personnel Act, which was created 60 years ago, are contrary to the equity of the current situation in 2022, and the conflicts continue to be drawn in terms of internal and external aspects of military human resources carrying out the "Defense Vision 2050" project, which is the keynote of the government's policy. In addition, this is linked to the national financial burden of military pension finances. Therefore, this study began with the need to revise the Military Personnel Act so that excellent human resources can continue to be introduced into a military system and perform stable duties through retirement age guarantee systems rather than class retirement.

• The Journal of the Convergence on Culture Technology
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• v.9 no.1
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• pp.443-448
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• 2023

Over the past five years, the number of patients with sleep disorders has increased by about 250,000 from 840,000 in 2017 to 1.09 million in 2021. In addition, sleep disorder is a factor that causes dementia risk factors, and furthermore, the population with sleep disorder is a very important policy issue in terms of stable health insurance financial management in the future in terms of national health management in the super-aging trend. Therefore, this study aims to establish an efficient treatment environment in medical institutions responsible for the current status of polysomnography and effective reimbursement policies for the recently increasing population with sleep disorders, and appropriate sleep management policies for future sleep disorders through correct implementation. We are trying to find out the actual condition and improvement plan through interviews with related organizations and experts.