• Transactions of Materials Processing
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• v.25 no.6
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• pp.379-389
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• 2016

As a stator for steam turbine diaphragm, hollow-type nozzle stator to substitute for conventional solid one is introduced in this study. This hollowed stator can be separated into two parts such as upper and lower plates with large and curved surface area. This study focuses on thick plate forming process for the upper plate of the hollow-partitioned nozzle stator. First, to reduce forming defects such as under-cut and localized thinning of the deformed plate, and to avoid tool interruption between forming punch and lower die, tool design including the position determination of forming surfaces is performed. Uni-axial tensile tests are carried out using SUS409L steel plate with initial thickness of 5.00mm, and plastic strain ratio (r-value) is also obtained. Due to the asymmetric curved configuration of the upper plate, it is hard to adopt a series of blank holder or draw-bead, so the initial plate during this thick plate forming experiences unstable and non-uniform contact. To easy this forming difficulty and find suitable tool geometry without sliding behavior of the workpiece in the die cavity, two geometric parameters with respect to each shoulder angle of the lower die and the upper punch are adopted. FE models with consideration of 21 combinations for the geometric parameters are built-up, and numerical simulations are performed. From the simulated and predicted results, it is shown that the geometric parameter combinations with ($30^{\circ}$, $90^{\circ}$) and ($45^{\circ}$, $90^{\circ}$) for the shoulder angle of the lower die and the upper punch are suitably applied to this upper plate forming of the hollow-partitioned nozzle stator used for the turbine diaphragm.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.10
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• pp.4661-4680
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• 2016

Cognitive radio (CR) technology is an effective solution to the spectrum scarcity issue. Collaborative spectrum sensing is known as a promising technique to improve the performance of spectrum sensing in cognitive radio networks (CRNs). However, collaborative spectrum sensing is vulnerable to spectrum data falsification (SSDF) attack, where malicious users (MUs) may send false sensing data to mislead other secondary users (SUs) to make an incorrect decision about primary user (PUs) activity, which is one of the key adversaries to the performance of CRNs. In this paper, we propose a coalition based malicious users detection (CMD) algorithm to detect the malicious user in CRNs. The proposed CMD algorithm can efficiently detect MUs base on the Geary'C theory and be modeled as a coalition formation game. Specifically, SSDF attack is one of the key issues to affect the resource allocation process. Focusing on the security issues, in this paper, we analyze the power allocation problem with MUs, and propose MUs detection based power allocation (MPA) algorithm. The MPA algorithm is divided into two steps: the MUs detection step and the optimal power allocation step. Firstly, in the MUs detection step, by the CMD algorithm we can obtain the MUs detection probability and the energy consumption of MUs detection. Secondly, in the optimal power allocation step, we use the Lagrange dual decomposition method to obtain the optimal transmission power of each SU and achieve the maximum utility of the whole CRN. Numerical simulation results show that the proposed CMD and MPA scheme can achieve a considerable performance improvement in MUs detection and power allocation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.620-626
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• 2017

This study conducted chemical and physical hazard analysis on the acidity, peroxide value, color removal, and limit criteria of metal detector of roasted laver. The Hunter color L- and a-value of roasted laver was higher than the control, and the b-value was higher at $400^{\circ}C$. The limit criteria establish by metal detector was determined to a sensitivity of 60 because it detected 100% in a sensitivity of 60 to Fe and Sus. The acidity and peroxide values increased with increasing temperature. These results confirmed that roasted laver is safe when roasted to $300^{\circ}C$ for 5 seconds.

• Journal of the Korean institute of surface engineering
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• v.31 no.3
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• pp.133-141
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• 1998

Stainless is widely used for various purposes due to its good corrosion resistance. There has been much research to produce the color stainless steel by several methods. In this experiment, TixN films have been deposited on the SUS304 substrate by the DC magnetron sputtering system and the color and texture of the films as a function of coating conditions has been studies. The TixN films showed a (111) preferred orintation in bias-free conditions. The texture of coated later was changed from (111) to (200) to (2200 with a change of the bias from -1000V to -3000V. When the bias is low, coated elements have low energy. Therefore, the texturct (111) of low surface energy. The mobility of atoms was increased with the increase of the blas and texture was changed to the other plane. Non-etched specimens all exhibited strong (111) texture. This result shows that (111) is a loose plane and of non-etched specimens all exhibited. High growing velocity of (111) of especially was main texture of Non-etched specimens. Low working pressure($4\times10^{-3}$torr) was more effective than figh working pressure ($6\times10^{-3}$torr) for the gold color of $Ti_xN$ film. L and b were increased and a was decreased with the increase of bias voltage. Accordingly, We obtained the near gold color of $Ti_xN$ film(L;92, a;1~1.5 b:24~29.50. As a result of reflectance. And as the bias increased, the reflectance was proportional to the increasing bias voltage, but we took the top reflectance when the bias voltage was -200V.

• Bulletin of the Korean Chemical Society
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• v.21 no.10
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• pp.969-972
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• 2000

[Fe II Fe III $BPLNP(OAc)_2](BPh_4)_2$ (1), a new model for the reduced form of the purple acid phosphatases, has been synthesized by using a dinucleating ligand, 2,6-bis[((2-pyridylmethyl)(6-methyl-2-pyridylmethyl)ami-no)methyl]-4-nitrophenol (HBPLNP) . Complex 1 has been studied by electronic spectral, NMR, EPR, SQUID, and electrochemical methods. Complex 1 exhibits two strong bands at 498 nm $(\varepsilon=$ 2.6 ${\times}10^3M-^1cm-^1)$ and 1363 nm $(\varepsilon=$ 5.7 ${\times}10^2M-^1cm-^1)$ in $CH_3CN.$ These are assigned to phenolate-to-FeIII and intervalence charge-transfer transitions, respectively. NMR spectrum of complex 1 exhibits sharp isotropically shifted resonances, which number is half of those expected for a valence-trapped species, indicating that electron transfer between FeⅡ and FeⅢ centers is faster than NMR time scale at room temperature. Complex 1 undergoes quasireversible one-electron redox processes. The $FeIII_2/FeIIFeIII$ and $FeIIFeIII/FeII_2$ redox couples are at 0.807 and 0.167 V ver-sus SCE, respectively. It has Kcomp = 5.9 ${\times}$10 1s(acetato) ligand combination sta-bilizes a mixed-valence FeIIFeIII complex in the air. Interestingly, complex 1 exhibits intense EPR signals at g = 8.56, 5.45, 4.30 corresponding to mononuclear high-spin FeⅢ species, which suggest a very weak magnetic coupling between the iron centers. Magnetic susceptibility study shows that there is a very weak antiferromag-netic coupling (J = $-0.78cm-^1$, H = $-2JS_1${\times}$S_2)$ between FeII and FeIII centers. Thus, we can suggest that complex 1 has a very weak antiferromagnetic coupling between the iron centers due to the electronic effect of the nitro group in the bridging phenolate ligand.

• Cross-Cultural Studies
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• v.34
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• pp.285-306
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• 2014

La historia sobre la ${\acute{e}}poca$ de la independencia y la $formac{\acute{o}}n$ de las naciones latinoamericanas enfatiza sobre todo los roles de los hombres y $espor\acute{a}dicamente$ de las mujeres. Se han considerado directrices las acciones de algunos criollos de esa epoca como $Sim{\acute{o}}n$ Bolivar y San Martín. La historiografía masculina-$c{\acute{e}}ntrica$ $est{\acute{a}}$ ignorando y marginando las luchas y los sacrificios de las mujeres que participaron en la independencia y la $formac{\acute{o}}n$ de las naciones. Por tanto, es preciso realizar una crítica a los procesos que han mantenido la tendencia machista, uno de ellos es porque no se han desatendido concepciones y cosmovisiones sobre el $g{\acute{e}}nero$. En fin, esta tendencia es porque no se ha superado la herencia colonial de manera crítica. En este contexto, este artículo intenta investigar los cambios sobre los puntos de vista y la manera de ver a las mujeres y sus actividades durante la ${\acute{e}}poca$ de la independencia. Puesto que las mujeres han sido consideradas como objetos que ocupan un espacio secundario en $comparaci{\acute{o}}n$ a los roles de los criollos. Este estudio pretende configurar nuevos puntos de vista para reestructurar nuestro enfoque tradicional sobre la independencia y las formaciones de las naciones latinoamericanas para poner en evidencia los roles de las mujeres en la historia.

• Tribology and Lubricants
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• v.34 no.6
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• pp.235-240
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• 2018

Superlubricity refers to the lubrication phenomenon that occurs when the friction coefficient is lower than 0.01. In recent years, this phenomenon has received a significant amount of attention because it can greatly contribute to the reduction of economic and environmental losses caused by friction and wear. In the case of acid lubricants, only ceramic materials can be used for superlubricity, and it takes a long running-in period to enter the superlubricity regime. In this work, we investigated the superlubricity effect of vitreous enamel coating on SUS304. We also examined the running-in period of vitreous enamel coating under phosphoric acid lubricant condition with respect to surface treatments. Drying and polishing methods were used to treat the vitreous enamel coating on the specimen. The friction experimental results revealed that superlubricity could be achieved with vitreous enamel coating. It was also found that the drying and polishing methods can significantly reduce the running-in period and improve the wear properties of vitreous enamel coating. In particular, the polishing method shortened the running-in period by approximately 99% and reduced the wear rate by approximately 99%, compared to nontreated vitreous enamel coating.

• Plant Breeding and Biotechnology
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• v.6 no.4
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• pp.337-353
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• 2018

We used Illumina/HiSeq sequencing for analysis of gene expression profiling among four maize seed types (dent, CM3 and CM6; waxy, CM5 and CM19) at 10 DAP (days after pollination). A total of 88,993,000 (CM3), 103,817,340 (CM6), 103,139,640 (CM5), and 66,978,958 (CM19) sequence reads were generated with read lengths of about 0.9, 1.0, 1.0, and 0.7 billion bp, respectively. We obtained 69.1 (CM3), 71.0 (CM6), 71.2 (CM5), and 71.8% (CM19) high quality reads from the raw data and compared them with reference RNA sequences in a public DB (NCBI). It was revealed that mapped reads were 58%, 63%, 62%, and 62% of the EST reference in CM3, CM6, CM5 and CM19, respectively; and more than 51,000 genes were expressed based on RPKM criteria (over 0.25 value) in each CM3, CM6, CM5, and CM19 inbred line. In differentially expressed gene (DEG) analysis, we found that 3,527 genes were differentially expressed by at least two-fold with 1,709 upregulated in the two waxy inbred lines and 1,818 upregulated in the two dent inbred lines. We also detected genes for the sucrose and starch biosynthesis pathways based on BINs, and different expression patterns between waxy and dent inbred lines were shown for the gene set for starch synthesis, such as sh2, bt2, du1, wx1, and ae1. Although some genes were more expressed in dent lines, most genes for starch synthesis were much expressed in waxy lines. Especially, there was greater expression of the sus2 gene in both waxy lines compared with the dent lines.

• Tribology and Lubricants
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• v.34 no.6
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• pp.241-246
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• 2018

This research addresses the improvement of tribo-systems, specifically regarding the reduction of friction and wear through tribo-coupling between tetrahedral amorphous carbon (ta-C) with different types of counterpart materials, namely bearing steel (SUJ2), tungsten carbide (WC), stainless steel (SUS304), and alumina ($Al_2O_3$). A second variable in this project is the utilization of different values of duct bias voltage in the deposition of the ta-C coating - 0, 5, 10, 15, and 20 V. The results of this research are expected to determine the optimum duct bias and best counter materials associated with ta-C to produce the lowest friction and wear. Results obtained reveal that the tribo-couple between the ta-C coating and SUJ2 balls produces the lowest friction coefficient and wear rate. In terms of duct bias changes, deposition using 5 V produces the most optimum tribological behavior with lowest friction and wear on the tribo-system. In contrast, the tribo-couple between ta-C with a WC ball causes penetration through the coating surface layer and hence high surface delamination. This study demonstrates that the most effective ta-C coating duct bias is 5 V associated with SUJ2 counter material to produce the lowest friction and wear.

• Journal of Ocean Engineering and Technology
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• v.33 no.4
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• pp.340-349
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• 2019

In the case of a fire accident on a ship or an offshore plant, the design of the bulkhead penetration piece must be verified via a fire test procedure (FTP), as specified by the Maritime Safety Committee (MSC). The purpose of this study is to verify both the numerical analysis results and the design specifications for penetration pieces that could be applied to the A60 class bulkhead division. In this study, the FTP was carried out in accordance with the test procedure prescribed in the MSC regulation. In order to review the fire resistance performance according to the material type, bulkhead penetration pieces for the FTP were made from brass, carbon steel for machine structures (S45C), and austenite stainless steel (SUS316). In addition, spray-type insulation and mechanical fastener-type insulation were applied to investigate the fire resistance performance according to the type of insulation. To verify the heat transfer numerical analysis results for the A60 class bulkhead penetrating piece from this test study, the design specifications of the penetrating piece material and the insulation type applicable to a ship and an offshore plant were identified.