• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.858-863
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• 1995

The nitrogenation process and magnetic properties of $Sm_{2}Fe_{17}N_{x}\;(0{\leq}x{\leq}3)$ were investigated. During the initial nitrogenation process, the nitrogen content had linear relation with the square root of nitrogenation time, and the activation energy for the process was calculated to be 102.4 kJ/mol. The magnetic properties of $Sm_{2}Fe_{17}N_{x}$ were strongly dependent on the nitrogen content and the composition having $Sm_{2}Fe_{17}N_{2.8}$ showed optimum magnetic properties with a Curie temperature of 450 oC. The intrinsic magnetic properties of the nitride at room temperature were $M_{s}=1147\;emu/cm^{3},\;K_{1}=4.6{\times}10^{7}erg/cm^{3},\;K_{2}=6.0{\times}10^{7}erg/cm^{3}\;and\;H_{A}=290\;kOe$, respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.8
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• pp.1046-1052
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• 2021

Artificial intelligence is being applied in various industrial fields to the development of the fourth industry and the construction of high-performance computing environments. In the medical field, deep learning learning such as cancer, COVID-19, and bone age measurement was performed using medical images such as X-Ray, MRI, and PET and clinical data. In addition, ICT medical fusion technology is being researched by applying smart medical devices, IoT devices and deep learning algorithms. Among these techniques, medical image-based deep learning learning requires accurate finding of medical image biomarkers, minimal loss rate and high accuracy. Therefore, in this paper, we would like to compare and analyze the performance of the Cross-Entropy function used in the image classification algorithm of the loss function that derives the loss rate in the chest X-Ray image-based deep learning learning process.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.33 no.5
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• pp.187-190
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• 2023

In this study, antibacterial glasses were developed by the addition of CaO in ZnO-Na₂O-B₂O₃-SiO₂ glass system. The effect of the addition of CaO on the thermal properties, dissolution properties, surface zeta potential and antibacterial activity were analyzed. Differential thermal analysis (DTA) analysis was performed to analyze the thermophysical properties of 30ZnO-xCaO-20Na₂O-30B₂O₃-(20-x)SiO₂ (x = 0, 2, 4, 6, 8, 10 mol%). It was confirmed that the glass transition temperature decreased as the CaO content increased. The amount of released Zn²⁺ ions and surface zeta potential of glass samples increased with increasing CaO concentration. For these reasons, the antibacterial activity was dramatically improved. By the addition of CaO, we could successfully develop an antibacterial glass with 99.9 % antibacterial activity against both Escherichia coli and Staphylococcus aureus.

• Journal of Advanced Navigation Technology
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• v.28 no.2
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• pp.193-200
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• 2024

This paper describes the design and development of a transmit receiver module(TRM) for mounting on X-band SAR of the NEXTSat-2. The TRM generates the chirp signal with required bandwidth through the DDS in X-band and performs frequency conversion, combination for the signal to transmit and be received and frequency synthesis. Tx path of the TRM produces signals of total 28 bandwidths up to 96.8 MHz and has output signal level of more than + 9.37 dBm. Rx path of the TRM has minimum noise figure of 15.7 dB. The measurement results show that required requirements are satisfied. The TRM is installed on the NEXTSat-2 flight model(FM), launched by KSLV-II(Nuri) on May 23, 2023 and currently operational.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.8 no.1
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• pp.7-10
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• 1975

The catches of mackerel by monofilament and multifilament net were compared by means of $x^2$ and t-test method. In order to improve the netting twine of drift nets, 6 shoots 5 different mesh and nylon-monofilament netting twines $(B\times2,\;C\;D,\;F,)$ and 2 shoe nylon-multifilament $(A\times2)$ which are using near the Jeju Island in contemporary days were used for the experiment. These gill no were connected in order of A, ,B, C, A, B, E, F and operated fly fishing boat Taeann Ho (7T) near sea of Jeju Ialand from May 1974 to August 1974. The results obtained are as follows: 1. B type nylon-monofilament gill nets were superior to nylon-multifilament gill nets in catch according to the result of $X^2$ test and t-test, and the catch ratio was $M_A:\;M_B=1:1.8$. 2. 75mm mesh size C, D nylon-monofilament gill nets were superior to 85mm mesh size nylonmonofilament gill nets, and their catch ratio were E, F: C, D=1:2.8. 3. The catch ratio C, D and E, F type nets were compared by means of t-teat, however could not recognized their relationship.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.1
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• pp.56-64
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• 2016

This study analyzed characteristics of officers' watch-keeping during fishing operation at the fisheries training ship KAYA (GT: 1,737 tons, Pukyong National University). It observed fishing works of three officers in wheel house of KAYA. The observations were carried out at the fishing ground 45 miles away from east of Jeju from 7 to 8 January 2010. The works and movements of the officers were recorded with three common video cameras and a 4-channel MPEG-4 Triplex DVR. Recorded data of the working circulation was analyzed by using the post-processing method. As a result of the traffic lines, the average (${\pm}S.D$) of working hour (min) and moving frequency (times), distance (m) and speed (m/min) during setting the net was 11.8 (0.9), 43.7 (8.1), 133.9 (35.8) and 10.5 (0.6), respectively. During trawling the net, it was 100, 241 (39.8), 615.7 (194.6) and 5.2 (1.6), respectively. During hauling the net, it was 17.6 (1.4), 41.0 (7.2), 196.9 (37.6) and 10.7 (0.8), respectively. In addition, it has a different tendency of the instrument usage frequency by the fishing works. During setting, the usage priority was CCTV, ECDIS, RPM and pitch controller, net monitor, GPS plotter, chart room, X-band radar, fish finder and public addressor. During trawling, it was CCTV, ECDIS, fish finder, X-band radar, net monitor, chart room, GPS plotter, RPM and pitch controller, auto pilot and steering, interphone, wind speed and direction indicator, No.1. VHF, navigation light control panel and public addressor. During hauling, it was CCTV, RPM and pitch controller, GPS plotter, public addressor, chart room, net monitor, X-band radar, auto pilot and steering and fish finder.

• Korean Journal of Crystallography
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• v.1 no.1
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• pp.49-56
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• 1990

The crystallizied Inactions of the two metastable phases in the glasses of plagioclase compositions were estimated by x-ray diffraction method. The orthorhombic metastable phase is easily drystaliized in the composition range of 70 to 80 mol% of albite, whereas the hexagonal metastable phase is mostly crystallized in the anonhite-rich side. For the purpose of refining the orthorhombic metastable structure some single crystal fragments of the composition Na,17ca‥‥All Isi2 nn were separated Som the crystallized glasses. The cell parameters of this crystal are a=8.237(1)A. b=8.644(1)A c=4.818(1)A. The space group of this crystal is Pn,2, Final atomic coordinates give R value of 0.040 and Rw of 0.028 with anisotropic thermal parameters. The position of Na and Ca atoms statistically distributed is splitted in two points with the occupancy of 0.5. The Si and Al atoms are statistically distributed in the six-membered ring of the Immm-type framework.

• Bulletin of the Korean Chemical Society
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• v.23 no.9
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• pp.1213-1221
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• 2002

Friedel-Crafts alkylation reaction of an isomeric mixture of 1,2,3,4,5,6,7,8- (2) and 1,2,3,4,5,6,7,8-octahydrophenanthrene (2') with excess vinylchlorosilanes such as vinyl(methyl)dichlorosilane (1a) and vinyltrichlorosilane (1b) in the presence of aluminum chloride catalyst at 80 $^{\circ}C$ gives only one dialkylated products, 9,10-bis[2-(chlorosilyl)ethyl]-1,2,3,4,5,6,7,8-octahydroanthrenes [(Cl2XSiCH2CH2)2C14H16: X = Me (4a), Cl (4b)] in good yields, but 9,10-bis[2-(chlorosilyl)ethyl]-1,2,3,4,5,6,7,8-octahydrophenanthrenes are not obtained. However, monoalkylation of 2 with 1 affords a mixture of both isomeric compounds, 9-[2-(chlorosilyl)ethyl]-1,2,3,4,5,6,7,8-octahydroanthracenes 3 and -phenanthrenes 3'. The yield of product 3' is always higher than that of 3. When a mixture of 3 and 3' is alkylated again with 1, only product 4 without phenanthrene type compounds is obtained, indicating that the isomerizations between 2 and 2', or 3 and 3'occur under the alkylation condition. The alkylation with dimethylvinylchlorosilane or trimethylvinylsilane did not proceed. The structure of 4a is determined by X-ray single crystal diffraction analysis.

• Korean Journal of Crystallography
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• v.8 no.2
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• pp.119-123
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• 1997

The complex [Ni(L)]I2 (1) (L:3,5,10,12-Tetramethly-1,4,8,11-tetraazacyclotetradecane) has been prepared and characterized by X-ray diffraction methods. The complex 1 crystallized in the orthorhombic system, space group Pcab with cell parameters a=13.293(1) Å, b=28.550(7) Å, c=10.804(1) Å, z=8. Least-squares refinement of 1 led to a R(Rw) factor of 0.043 (0.046) for 1851 observed reflections of Fo>3o (Fo). The crystal structure of 1 has a slightly distorted square-planar geometry and adopts the trans-III conformation.

• Journal of Integrative Natural Science
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• v.6 no.4
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• pp.197-204
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• 2013

The crystal structure of the potential active 4,6-dimethyl-9-phenyl-8,12-dioxa-4,6-diazatetracyclo [8.8.0.02,7.013,18] octadeca-2(7),13,15,17-tetraene-3,5,11-trione 2-ethoxyphenyl (2E)-but-2-enoate ($C_{22}H_{18}N_2O_5$) has been determined from single crystal X-ray diffraction data. In the title compound crystallizes in the monoclinic space group $P_12_1/c_1$ with unit cell dimension a=15.2039(8), b=12.3888(6) and c= 9.8162(5) [alpha & $gamma=90^{\circ}$ beta=98.113(2)]. In the structure fused pyrone and pyran rings each adopt a sofa/envelop conformation. The crystal structure is stabilized by intramolecular C-H... O hydrogen bond interaction.