• Korean Journal of Microbiology
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• v.44 no.1
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• pp.63-68
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• 2008

Strain Kan-23 was extracted from nematophagous fungi, which were isolated from the soil sample of oriental melon field. The strain exhibited the slow-growing characteristic forming conidia after prolonged incubation for 30 days. Morphological features of strain Kan-23 were observed under scanning electron microscope (SEM). It possesses erect conidiophores which contain $2{\sim}3$ side branches, with each branch producing $5{\sim}10$ conidia. The size of conidiophores were between $160{\sim}450\;{\mu}m$. Conidia were ellipsoidal with three septa[septum] in each conidium. Strain Kan-23 captured nematodes by means of giant constricting rings, which were observed in the glucose peptone agar medium. ITS region of rDNA sequence was analyzed. On the basis of the high sequence similarity of ITS region (99%), the Kan-23 strain was closely related to Drechslerella brochopaga (U51950). This is the first report on Drechslerella brochopaga as a nematophagous fungus in Korea.

• Korean Chemical Engineering Research
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• v.43 no.6
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• pp.662-667
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• 2005

2,3-Dihydrobenzofuran derivatives, important intermediates of medicines and agricultural chemicals, were prepared from aryl methallyl ethers over MCM-41 mesoporous material catalysts. Two mesoporous materials with Si/Al mole ratios of 40 and 50 were prepared to investigate the effect of acid site concentration on their catalytic activities. Aryl methallyl ethers with various substituents on their benzene rings were used to investigate the effect of electron density on benzene ring on the conversion of the ethers and the yield of 2,3-dihydorbenzofuran derivatives. The catalyst with a high acid site concentration showed high conversions, but it is difficult to correlate the yield of the derivatives with the acid site concentration. The increase in the electron density of the benzene ring by introducing electron-donating groups accelerated Claisen rearrangement reaction, resulting in the enhanced yield of the derivatives. On the other hand, the decrease in the electron density by introducing electron-attracting groups accelerated the cracking reaction of aryl methallyl ether by acid catalysts, producing phenol derivatives rather than 2,3-dihydrobenzofuran derivatives.

• Journal of Korean Society of Forest Science
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• v.10 no.1
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• pp.41-45
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• 1970

This study was carried out to investigate the identification of the woods of commercially important exotic tree species grown in Korea. The test trees used in this study were selected 21 species grown in Kwangyang and Suwon, Korea. The items of macroscopical features were observed and examined principally on the annual rings, transitions spring to the summerwood, pore types and arrangements, sap and heartwoods, wood colors, odor and tastes, resin ducts, parenchymas, and rays etc. The microscopical features observable in the elements, and their compositions such as vessels, tracheids, wood fibers, ray parenchyma cells, and intercellular cannals were observed and measured. The observed and measured results investigated were synthesized, and accordance with these results macroscopical and microscopical keys were prepared for the wood identification as seen in the text.

• Journal of the Korea Fashion and Costume Design Association
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• v.11 no.1
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• pp.1-16
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• 2009

Ip-yeong or gat-keun decorate heuk-rip, supplementing its simplicity. When the wind blew, a dynamic beauty was created, especially if the gat-keun was made with long straps of jade or silk. Basically, ip-yeong was a practical chin strap to hold the gat tight on the head. Commoners made ip-yeong by folding cotton cloth or fine gauze. However, as available materials became diversified, people used cloth, jade, agate, amber, coral, gold medallion, rock crystal and bamboo as well, juk-yeong, which was made with bamboo, became popular especially when Heungsun Daewon-gun, the father of King Kojong, decreed that people wear simple clothes. Most records concerning ip-yeong in Chosun-wangjo-shillok, the authentic record of the Joseon Dynasty, are related to forbidding a sumptuous life. The book also suggests that ip-yeong was bestowed by the king or was offered to foreign diplomats as gifts. Ip-yeong doesn't seem to be a unique system for Korea. Based on portraits or paintings where ip-yeong can be found, it seems to have been widely used during the Yuan dynasty and the Goryeo dynasty. The system disappeared in China as the Ming Dynasty was established, but it remained in use in the Korean Goryeo dynasty and through the Joseon. Literature suggests that the same materials were used for ip-yeong from the beginning of Joseon to the end of the dynasty. Guyeongja refers to a ring that connects an ipja to a chin strap. Guyeongja made with silver, bronze and jade still remain. In gungjungbalgi, the royal court inventory book, records of imogarye can be found (1882), where ten pairs of pure gold strap rings and ten pairs of gold-plated ones were used for a royal wedding.

• Journal of Satellite, Information and Communications
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• v.11 no.2
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• pp.29-35
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• 2016

High-availability seamless redundancy (HSR) is a fault-tolerant protocol for Ethernet networks that provides two frame copies for each frame sent. Each copy is forwarded on a separate physical path. HSR is a potential candidate for several fault-tolerant Ethernet applications, including smart-grid communications. However, the major drawback of the HSR protocol is that it generates and circulates unnecessary frames within connected rings regardless of the presence of a destination node in the ring. This downside degrades network performance and can deplete network resources. Two simple but efficient approaches have previously been proposed to solve the above problem: quick removing (QR) and port locking (PL). In this paper, we will present a hybrid approach, QRPL, by combining QR with PL, resulting in further traffic reductions. Our analysis showed that network traffic is significantly reduced for a large-sized HSR connected ring network compared to the standard HSR protocol, QR, and PL.

• Tribology and Lubricants
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• v.32 no.5
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• pp.141-146
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• 2016

The diketopyrrolopyrrole (DPP) pigment is a bicyclic 8-π-electron system containing two lactam units. Typical DPP derivative pigments have melting points of over 350°C and very low solubility in most solvents, and show absorption in the visible region with a molar extinction coefficient of 33,000 dm²mol⁻¹ and strong photoluminescence with maxima in the range 500–600 nm. X-ray structure analyses of DPP show that the whole molecule is almost in one plane. The phenyl rings are twisted out of the heterocyclic plane and the intermolecular hydrogen bonding between neighboring lactam NH and carbonyl units influences the structure of the DPP pigment in the solid state. In this study, mono-N-alkylation and mono-N-arylation were undertaken for Pigment Red 264 or Pigment Orange 73 with alkyl halide and aryl halide, respectively, in the presence of sodium tert-butoxide as a base catalyst to improve the solubility of DPP pigments and their application as CO₂ indicators. The synthetic yield was in the range 11–88%. The indicator dyes are highly soluble in organic solvents and shows pH-dependent absorption (λ_max 501 and 572 nm for the protonated and deprotonated forms, respectively) and emission (λ_max 524 and 605 nm for the protonated and deprotonated forms, respectively) spectra. The mono-N-alkylated and mono-N-arylated DPP pigment was identified by ¹H-NMR (¹H-Nuclear Magnetic Resonance Spectrometer), FT-IR (Fourier Transform Infrared Spectroscopy), and MS (Mass Spectrometry). According to the results of color and hue properties obtained by a color matching analyzer, the synthesized DPP pigment material can be used as a CO₂ indicator.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.8
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• pp.17-25
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• 1998

Aluminum alloys have low density, relatively high strength and yield strength, good plasticity, good machinability, and high corrosion and acid resistance. Therefore, they are suitable for large containers for the food, chemical and other industries. Large containers are often bodies of revolution consisting of shell courses, stiffening rings, heads and other elements joined by annular welds. Larger containers have longer welds and require greater leak-tightness and higher weld mechanical properties. The LNG tank consists of aluminum plates with various sizes, so its construction should by divided by several sections. Moreover, each section has its own sub-section consisted of several aluminum plates. To guarantee the quality of huge LNG tank, therefore, the precise control of plate dimension should by urgently needed in conjunction with the appropriate selection of process parameters such as cutting speed, depth of cut, rotational speed and so on. In this paper, a manufacturing system was developed to implement automatic circular tracking in height direction and automatic circular interpolation in depth of cut direction. Also, the neural network based on the backpropagation algorithm was used to predict the cutting quality and motor load related with the life time of the developed system. It was revealed that the manufacturing system and the neural network could be effectively applied to the bevelling process and to predict the quality of machined area and the motor load.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.7
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• pp.1390-1406
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• 1994

This study deals with the DMCLP(Delay constrained Minimum Cost Loop Problem)-one of problems arising in the design of local access computer networks. The problem consists of finding a set of rings to satisfy the traffic requirements of end user terminals. In the problem, the objective is to minimize the total link cost. This paper presents heuristic algorithm which consists of two phases for this problem, under the constraints that the number of nodes served by a single ring is limited and network mean delay is dropped within the desired time. The algorithm is derived using the clusters obtained by the existing MCLP(Minimum Cost Loop Problem) algorithm and a trade-off criterion explained in the paper. Actually, simulation results in that the proposed algorithm in this paper produces better solution than the existing MCLP algorithm modified. In addition, the algorithm has the relatively short running time.

• Journal of Chest Surgery
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• v.28 no.12
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• pp.1079-1095
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• 1995

Recently endogenous digitalis-like substances were found in the blood of various cardiovascular diseases and they have been considered one of the causes of evoking hypertension. However, the mechanism of endogenous digitalis-like substances-induced hypertension is not clarified yet. Therefore, the effects of Na-K pump inhibition on the contractility of vascular smooth muscle[conduit and resistant artery were investigated, using organ bath and bioassay experiment. Aortic and carotid arterial rings[conduit artery and the branches of brachial and superior mesenteric artery[resistant artery were used to find the effect of Na-K pump inhibition. The results obtained were as followes;The magnitudes of contractions induced by norepinephrine, serotonin, or acetylcholine in all these arteries were significantly increased by the inhibition of Na-K pump. The increased contractile responses to these agonists, especially to serotonin, were much more prominant in resistant arteries. Nitroprusside-induced relaxations were attenuated by Na-K pump inhibition and there were no significant differences in the effects of Na-K pump inhibition on nitroprusside-induced relaxations of these blood vessels. Endothelium-dependent relaxation was suppressed by the inhibition of Na-K pump, especially by the administration of ouabain, and this inhibitory effect was much more prominent in the branches of superior mesenteric artery, compared with other arteries. In the branches of superior mesenteric arteries, endothelium-dependent relaxation was completely blocked by ouabain. The release of EDRF was partially suppressed by Na-K pump inhibition.From the above results, it is suggested that the hypertension due to the increase in vascular resistance can be evoked by the inhibition of Na-K pump and endogenous digitalis-like substances induce hypertension through this mechanism.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.89-89
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• 2010

The atomic structure of Sb/Si(5 5 12)-$2{\times}1$ surface, deposited at room temperature (RT) and post-annealed, has been identified by scanning tunneling microscopy and the corresponding interface has been studied by synchrotron core-level photoemission spectroscopy. With 0.3-nm Sb deposition at RT and postannealing at $600^{\circ}C$, the surface has been facetted to (225)-$2{\times}1$ and (112)-$1{\times}1$, and its Si 2p has shown that all the Si 2p surface components have disappeared, while the single Sb-Si interfacial component has appeared. Such results indicate that all of surface Si atoms are replaced by Sb atoms and the charge is transferred from Si to passivating Sb-atoms at the top layer. With subsequent postannealing up to $700^{\circ}C$, the surface has been facetted to (113)-$2{\times}2$ and (335)-$4{\times}2$, still having Sb-Si interfacial component and partially re-exposed Si surface components. From the present study, the role of surfactant atom, Sb, as well as the thermal-stabilization of Sb-passivated high-index Si surface will be exposed. Especially, the key role of the Sb/Si(113)-$2{\times}2$, composed of Rebonded-Dimer-Rebonded atom 1D structures, for stabilization will be discussed.