• Journal of the Korean institute of surface engineering
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• v.31 no.6
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• pp.334-344
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• 1998

Yew coating pmccss t.o form a surface layer ol CrN phasc on mild steel (A81 1020!, AlSI Hi3, 1Cr-0.5Mo steel (ASTM A213 and Nickrl-base superalloy (Inconel 718) was developed. Surlaces of various alloys t,n.ateii by chromizing for the formation ol Cr diffusion layer was subsequently trcaled by plasma nitriding in order t.o form the hard CrS coating layer on the surfaces. This duplex plasma surface tri-atments of chromizing and plasma nitriding have induced a lormation of a duplex-lrcated surfacr hyer of approximat~ls 70-80 $\mu\textrm{m}$thickncss with a iargcly improved microiiardnrss up to approxiniateW 1500Hv(50gf). The main cause for the lage improvment in the surface hardncss is altribilted to [.he fact that CrN and $Fe_xN$ phases are created successfully by ccliromizins and plasma nilriding treatment. High tenipera1,urc wear resislance of the duplex-treated mild steel and HI3 steels at $600^{\circ}C$ was examined. Comparing the duplex-treated specimens with the specimens treated only by chromizing, the rcsults shovmi that, thc wear volume of the duplex-treated mild skcl and 1113 stcel aSt.er a wear test, at $600^{\circ}C$ were reduced hy a Iactor of 8 and 3, respectively. Characteristics of the CrS phase by duplrx treatment were compared with $CrN_x$,/TEX> film by ion plating and the wear behaviors of CrN film lormed by two different nroccsses arc nea.riy identical.

• Journal of Biosystems Engineering
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• v.35 no.4
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• pp.224-230
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• 2010

The purpose of this study was to develop position control system of an electric actuator for automatic shuttle shifting of a tractor. The electric actuator was installed at the link of the forward-reverse gearshift of the tractor transmission, and controlled in the ranges of forward, neutral, and reverse positions. The position control system of the electric actuator was developed based on PID (Proportional Integral Derivative) controller and transfer function of the electric actuator. The coefficients of the PID controller were determined by Ziegler-Nichols (Z-N) method and optimized using simulation program. The prototype AMT (Automated Manual Transmission) test unit of the tractor was installed and used to evaluate the performance of the position control. The evaluation system for the control performance consisted of forward-reverse actuator, motor driver, and controller. The tests were conducted as the controlled positions of the actuator were changed from neutral position to forward, neutral, and reverse positions in sequence. The sequential tests were repeated 20 times. The operations of changing the gearshift were considered as the step response of the control system. Maximum overshoot, settling time, and steady-state error were analyzed. The results showed that performance of the position control system was reasonable and qualified. The maximum overshoots, the steady-state errors, and the settling times of the position control system were 10~20%, 1~5%, and 0.92~1.49 sec, respectively. The modifications of the electric actuator will be required to enhance the performance of position control during field operation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.12A
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• pp.1174-1182
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• 2005

This paper, we propose a new channel Estimation method for MB-OFDM(Multi-Band OFDM) system that is suggested as one of standards in IEEE 802.15 TG3a for high data rate(110Mbps${\~}$480Mbps) WPAN system. The proposed method uses correlation characteristic of the PS(Packet Synchronization) sequence for timing synchronization. It can reduce the influence of noise compared with the conventional algorithm which based on LS(Least square) algorithm is redundancy without using the CE(Channel Estimation) Sequence for channel Estimation. We simulate both conventional method and proposed method for performance analysis in S-V channel environment which proposed by IEEE 802.15.3a. Simulation results show the proposed algorithm outperforms conventional algorithm about 1${\~}$1.5dB of Eb/NO.

• The Plant Pathology Journal
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• v.16 no.6
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• pp.306-311
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• 2000

A new strain of Cucumber mosaic virus (CMV) from easter lily (Lilium longiflorum), Ly2-CMV, was identified and compared to the well-characterized Mf-CMV (subgroupⅠ) and LS-CMV (subgroupⅡ) by host reaction in several indicator plants, dsRNA analysis, serological property, RT-PCR analysis, restriction enzyme profile of the PCR products and nucleotide sequence of coat protein (CP) gene. Remarkable differences in symptoms of Ly2-CMV were found between Mf-CMV or LS-CMV in tobacco plants and Datura stramoinium. Ly2-CMV induced small necrotic ringspots on the inoculated leaves of Nicotiana tabacum cvs. Xanthi nc and Burley 21 and D. stramonium, and failed to infect these species systemically. Of the indicator plants tested, N. benthamiana only reacted with systemic infection by inoculation of Lr2-CMV. In experiments of dsRNA analysis, serology and RT-PCR of CP gene, Ly2-CMV was come within subgroupⅠ CMV. However, restriction enzyme analysis of the PCR products using MspⅠ showed that Ly2-CMV was distinct to Mf-CMV. The CP gene of Ly2-CMV contains 657 nucleotides, and the nucleotide sequence is similar to that of Mf-CMV. There is also a high degree of conservation between their putative gene products in Ly2-CMV and Mf-CMV, with five amino acid changes in the 218 amino acids of the CPs.

• Korean Journal of Weed Science
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• v.12 no.4
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• pp.374-379
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• 1992

Response of medicinal plants(58 species in 28 families) cultivated or naturally grown in Korea on paraquat (1,1'-dimethyl-4,4'-bipyridinium ion) was determined. All the plants, except for Jiwhang(Rehmannia glutinosa Liboch.) were killed by paraquat at 0. 8kg $ha^{-1}$. Jiwhang showed a great resistance to paraquat. The phytotoxic effect did not occur in Jiwhang with paraquat applied at 3.2kg $ha^{-1}$. Only 10% growth inhibition of Jiwhang was obtained at 4.8kg $ha^{-1}$. Normal growth of Jiwhang also occurred when at 0.8kg $ha^{-1}$ of paraquat different application dates from 2 leaf stage(LS) to 8 LS and/or five-repeated applications at 20-day intervals starting from 3 LS were employed. However, Jiwhang was completely killed by glyphosate[N-(phosphonomethyl) glycine], 2,4-D[2,4-dichlorophenoxy) acetic acid], and dicamba[3,6-dichloro-2-methoxy benzoic acid]+2, 4-D at the respective recommended rates.

• Korean Journal of Weed Science
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• v.16 no.3
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• pp.194-199
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• 1996

Seed size and days required to reach specific growth stages were determined for Echinochloa crus-galli (L.) P. Beauv. varieties which are major grass species found in Korean paddy field and the results were compared with E. frumentacea (Roxb.) Link. In addition, responses of the Echinochloa species on preemergence herbicides (molinate, esprocarb, and mefenacet) were investigated with respect to time of application. One thousand seed weight of E. crus-galli var. oryzicola was about 3 times heavier than that of var. praticola, but was not significantly different that of E. frumentacea. Days requited to reach the 2.5 leaf-stage (LS) were 11, 13, and 14 days after seeding for E. frumentacea, E. crus-galli var. oryzicola, and E. crus-galli var. praticola, respectively. E. crus-galli var. praticola was more sensitive to molinate, esprocarb and mefenacet than var. oryzicola and the sensitivity of both the varieties decreased as the time of application LS was delayed. However, there was no great difference in the response for E. frumentacea when applied between 1.5 and 3.0 LS. In thiocarbamate hebicides esprocarb was more active to Echinochloa species than molinate and the higher the active ingredient of the herbicides, the greater was the activity to Echinochloa species. Differential susceptibility of Echinochloa species to the herbicides was not related to the seed size, but to the early growth stages at the time of herbicide application which were affected by the seed size.

• Bulletin of the Korean Chemical Society
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• v.33 no.2
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• pp.651-656
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• 2012

Cationic immunoliposomes were prepared by conjugation of Fab' fragments of the recombinant humanized monoclonal antibody (HuCC49) against tumor-associated glycoprotein (TAG)-72 to sterically unilamella liposomes. The cationic immunoliposomes are composed of cationic lipid (O,O'-dimyristyl-N-lysyl aspartate, DMKD), cholesterol, and 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-N-[maleimide(polyethyleneglycol)$_{2000}$] (DPPE-PEG-maleimide) with a molar ratio of 0.5:0.47:0.03. Plasmid DNA was effectively condensed by addition of transferrin (Tf) during the formation of anti-TAG-72 PEG-immunolipoplexes (PILPs). These anti-TAG-72 PILPs were able to adhere to the surface of TAG-72-overexepressing LS174T human colon cancer cells more effectively than conventional liposomes, thereby facilitating gene delivery in vitro. Furthermore, intravenous administration of the anti-TAG-72 PILPs into the tumor-carrying mice exhibited efficient localization of the reporter gene in the tumor tissues.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.181-181
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• 1999

Self-assembled monolayers(SAMs) of alkanethiol have been formed on the Cu(111) surfaces in vacuum. The thermal behavior of octanethiol-based SAMs on the Cu(111) surface have been examined in ultrahigh vacuum. Using X-ray photoelectron spectroscopy (XPS), it is found that the monolayers are stable up to about 500K in vacuum. Decomposition is signaled by a decrease in the intensity of C ls peak, accompanied by an increase of the intensity of the Cu 2p peak. However, the intensity of the S 2p peak doesn't change much as a function of annealing temperature. Thermal the decomposition mass spectra show that n-alkene is the predominant species desorbing from the surface in the 500-600K temperature range. The totality of these data leads to the conclusion that the monolayers decompose through the S-C bond cleavage by hydrogen elimination reaction, resulting in the desorption of hydrocarbon moiety as n-alkene. Following this initial decomposition step, Cu2S layers are observed on the surface. For comparison, attempts were also made to examine the thermal behavior of octanethiol-based SAMs on the Cu(111) surface in air. It has been shown that the SAMs on the Cu(111) surfaces begin to desorb with the oxidation of the thiolate to sulfonate at 400K. Upon annealing to 450K, the monolayer has almost completely desorbed as indicated by the virtual disappearance of the S 2p peak.

• Steel and Composite Structures
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• v.23 no.2
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• pp.153-160
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• 2017

It is extremely important to be aware of the ballistic performances of engineering materials in order to be able to choose the lightest armor providing full ballistic protection in civil and military applications. Therefore, ballistic tests are an important part of armor design process. In this study, ballistic performance of plates made of carbon steel and cold worked tool steel against 7.62 mm AP (armor-piercing) bullets was examined experimentally and numerically in accordance with NIJ standards. Samples in different sizes were prepared to demonstrate the effect of target thickness on ballistic performance. Some of these samples were coated with titanium nitride using physical vapor deposition (PVD) method. After examining all successful and unsuccessful samples at macro and micro levels, factors affecting ballistic performance were determined. Explicit non-linear analyses were made using Ls-Dyna software in order to confirm physical ballistic test results. It was observed that the ballistic features of steel plates used in simulations comply with actual physical test results.

• Journal of the Korean Chemical Society
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• v.32 no.3
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• pp.195-202
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• 1988

An electrochemical reduction on the 3-phenyl-4-nitrosydnone in acetonitrile solution has been studied by direct current, differential pulse polarography, cyclic voltammetry and controlled potential coulometry. Before the cleavage of phenyl-N single bond a irreversible electron transfer-chemical reaction(EC) mechanism of nitro functional group proceeded to form amino (or-hydroxylamino) group by multielectron transfer which is followed to give phenyl hydrazine by single electron transfer-chemical reaction at the 2nd and 3rd irreversible reduction wave of high negative potential region. The cathodic half-wave potentials shown to be shift negative due to inhibitory effect of cetyl-trimethyl ammonium bromide micelle while reversible anodic peaks on the 2nd and 3rd reduction waves in the presence of NaLS at high negative potential region.