• Title/Summary/Keyword: H.W.O.S.T

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Raman spectra of Diamond thin film grown from $CH_4-H_2-O_2$ system ($CH_4-H_2-O_2$계로부터 성장된 Diamond 박막의 Raman spectra)

  • Geun, H.K.;Park, S.T.;Cho, J.G.;Park, S.H.;Park, J.C.
    • Proceedings of the KIEE Conference
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    • 1994.07b
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    • pp.1490-1492
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    • 1994
  • Diamond thin films were deposited on Si substrate from $CH_4-H_2-O_2$ system by MWPECVD at the condition of power of 800W, pressure of 80torr, $H_2$ flow rate of $75{\sim}81sccm$, $O_2$ flow rate of $0{\sim}3.8sccm$, $CH_4$ flow rate of $4.8{\sim}9sccm$, substrate temp, of $950{\sim}1010^{\circ}C$ and deposition time of 5hr. The deposited films were characterized by SEM, XRD and Raman spectroscopy. The growth rates of thin films and particles was measured. Good quality were synthesized at 40% of oxygen concentration which 6% of fixed metane concentration, and at 50%. Its deposition rates were $2.4{\mu}m/h$ respectively. As oxygen concentration increased, it was known that the broad peak of $1350 cm^{-1}$ was shifted to $1332cm^{-1}$ due to etching of carbon component.

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Friction Behavior of High Velocity Oxygen Fuel (HVOF) Thermal Spray Coating Layer of Nano WC-Co Powder

  • Cho, T.Y.;Yoon, J.H.;Kim, K.S.;Fang, W.;Joo, Y.K.;Song, K.O.;Youn, S.J.;Hwang, S.Y.;Chun, H.G.
    • Journal of the Korean institute of surface engineering
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    • v.40 no.4
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    • pp.170-174
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    • 2007
  • High Velocity Oxygen Fuel (HVOF) thermal spray coating of nano size WC-Co powder (nWC-Co) has been studied as one of the most promising candidate for the possible replacement of the traditional hard plating in some area which causes environmental and health problems. nWC-Co powder was coated on Inconel 718 substrates by HVOF technique. The optimal coating process obtained from the best surface properties such as hardness and porosity is the process of oxygen flow rate (FR) 38 FMR, hydrogen FR 57 FMR and feed rate 35 g/min at spray distance 6 inch for both surface temperature $25^{\circ}C\;and\;500^{\circ}C$. In coating process a small portion of hard WC decomposes to less hard $W_2C$, W and C at the temperature higher than its decomposition temperature $1,250^{\circ}C$ resulting in hardness decrease and porosity increase. Friction coefficient increases with increasing coating surface temperature from 0.55-0.64 at $25^{\circ}C$ to 0.65-0.76 at $500^{\circ}C$ due to the increase of adhesion between coating and counter sliding surface. Hardness of nWC-Co is higher or comparable to those of other hard coatings, such as $Al_2O_3,\;Cr,\;Cr_2O_3$ and HVOF Tribaloy 400 (T400). This shows that nWC-Co is recommendable for durability improvement coating on machine components such as high speed spindle.

Di(propylene glycol) Methylether (DPGME) Sensing Characteristics of SnO2-ZnO Sensor (SnO2센서의 ZnO 첨가량에 따른 di(propylene glycol) methylether (DPGME)에 대한 반응 특성)

  • Cha G. Y;Baek W. W;Yun K. Y;Lee S. T;Choi N. J;Lee D. D;Huh J. S
    • Korean Journal of Materials Research
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    • v.14 no.3
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    • pp.224-228
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    • 2004
  • Respectively the powder made of ZnO added $SnO_2$ was prepared by coprecipitation method and the thick film gas sensor was fabricated by screen-printing technique, The morphology and phase of the powder and film was investigated by SEM and XRD. The specific area of the particle was linearly increased with ZnO contents. Target gas was di(propylene glycol) methylether ($CH_3$($OC_3$$H_{6}$ )$_2$OH, DPGME), which is simulant gas of blister gas. The gas sensing characteristics for DPGME were examined with flow type measurement system and the concentrations of target gas were controlled from 500 ppb to 1500 ppb. ZnO (2 wt%) added $SnO_2$ showed maximum sensitivity to DPGME at $300^{\circ}C$.

The vortex dynamics in $Bi_2$$Sr_2$Ca$Cu_2$$O_8$single crystals unirradiated and with low-density columnar defect (저밀도 원통형 결함이 $Bi_2Sr_2CaCu_2O_8$ 단결정의 볼텍스 동역학에 미치는 영향)

  • Lee, T.W.;Lee, C.W.;Shim, S.Y.;Ha, D.H.;Kim, D.H.
    • Progress in Superconductivity
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    • v.3 no.1
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    • pp.36-40
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    • 2001
  • We have studied vortex dynamics in$ Bi_2$$Sr_2$$CaCu_2$O$_{8}$single crystals of unirradiated and irradiated samples by using 100 $\times$ $100\mu\textrm{m}^2$Hall sensor. Doses equivalent magnetic fields are 20 G, 100 G and 1 kG. In the magnetization measurement, a second magnetization peak (SMP) was observed in unirradiated, 20 G dose and 100 G dose samples in contrast to 1 kG dose sample. In the unirradiated sample, the SMP was observed in the range of 18 K ~ 35 K and the amplitude of the SMP decreased with increasing temperature. With increase of the irradiation dose, temperature region and sharpness of the SMP were reduced. In the magnetic relaxation measurement, we observed that the normalized relaxation rate S decreased with increasing the irradiation dose. Our results suggest that the vortex dynamics is not greatly affected by low-density columnar defects.s.

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Clinical Study on 1 Case of patient with Urinary Retention (요폐환자(尿閉患者) 1례(例)에 대한 임상적(臨床的) 고찰(考察))

  • Kim, Jae-Hyeng;Cho, Chung-Sik;Kim, Chul-Jung
    • Journal of Haehwa Medicine
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    • v.14 no.1
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    • pp.43-49
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    • 2005
  • One case of patient with urinary retention was reported in this clinical study. After the study, the results were as follows: 1. Anulesis belongs to l$\acute{o}$ng-bi(癃閉) in oriental medicine and the patient of this case belongs to chronic anulesis. 2. The patient of this case was thought as broke out anuresis by vesical nerve palsy of diabetic bladder pathy and sequela of stroke, and ischuria of long lie down 3. The patient of this case changeable process is supposed to urinary frequency, 'bi(閉)', 'l$\acute{o}$ong(癃)', urinary incontinence and urinary frequency. 4. First time of drug treatment is GAMIPHALJENG-SAN(ji$\bar{a}$-w$\grave{e}$i-b$\bar{a}$-h$\bar{e}$ng-s$\check{a}$n) by oral administration that action of alleviate a fever, water utilization and metaphase, convalescence time of drug treatment is PHALMIWANGAMI (b$\bar{a}$-w$\grave{e}$i-w$\acute{a}$n-ji$\bar{a}$-w$\grave{e}$i), YIKLUENG-TANG(yi-ling-t$\bar{a}$ng), CHUKYOO-TANG(s$\grave{u}$-ni$\grave{a}$o-t$\bar{a}$ng) that action of recreation. 5. Accupuncture treatment is s$\bar{a}$n-x$\bar{i}$ng-xuw$\acute{e}$, zw$\acute{u}$-s$\bar{a}$n-li, qi-h$\check{a}$i, gu$\bar{a}$n-yu$\acute{a}$n, zh$\bar{o}$ng-ji by mild supplementing and reducing manipulation of needle and heat accupuncture is qi-h$\check{a}$i, gu$\bar{a}$n-yu$\acute{a}$n, zh$\bar{o}$ng-ji-xu$\acute{e}$. 6. The other treatment is a sitz bath that prevent of urinary tract infection, and relieve of initial acute auresis by using of urethral catheterization.

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Association of Sequence Variations in DGAT 1 Gene with Economic Traits in Hanwoo (Korea Cattle)

  • Kong, H.S.;Oh, J.D.;Lee, J.H.;Yoon, D.H.;Choi, Y.H.;Cho, B.W.;Lee, H.K.;Jeon, G.J.
    • Asian-Australasian Journal of Animal Sciences
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    • v.20 no.6
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    • pp.817-820
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    • 2007
  • The effects of diacylglycerol O-acyltransferase (DGAT1) candidate gene polymorphism on the economic traits of Hanwoo were studied. Through sequencing analysis, two polymorphism sites at K232A and T11993C were established and were analyzed by PCR-RFLP. The PCR-RFLP analysis for K232A showed that the frequencies of alleles K and A were 0.75 and 0.25, respectively, and the frequencies of genotypes for K/K, K/A and A/A were estimated as 0.509, 0.491 and 0, respectively. In the PCR-RFLP analysis for T11993C, we found allele frequencies of 0.773 and 0.227 for T and A, respectively, and 0.546, 0.454 and 0 for the T/T, T/C and C/C genotype frequencies, respectively. No significant effects on economic traits in Hanwoo were found in the separate analysis of K232A and T11993C polymorphisms, but the interaction between K232A and T11993C showed a significant effect (p<0.005) on marbling score. The DGAT1 candidate gene was found to have a significant effect not only on milk yield and component traits but also on the metabolism of intramuscular fat.

일본의 과학 및 학술 정보 정책의 수립 과정과 실시 체제의 분석

  • 현규섭
    • Journal of the Korean Society for information Management
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    • v.5 no.1
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    • pp.31-52
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    • 1988
  • The information policy in Japan have bccir growing rapldlr 111 recent vttars. \'arioi~s level of govc~riimerital organrzatlons, ir~bt~tution arid agrircics have undt~rtak~~rr iriforrnatiori polrcy 111 order to i r l - crease information flow toward tlie society in Japan. At tlie same trme, computerized library systems also h a w uridergoirc rapid expansion. NACSIS(National Ceriter for- Science Informat~on System) wl~icl~ was cstablisl~ed bv Mirristr> of Etlr~c~arion, Sc~ence arid Culture haw witnessed dramatic adv;rnces i r i promoting for corrstructiori of database so as to provide their 11rf'3r.mat1orr nu nationwide scale. T l r i h articlr inrroduccs tlie actr\rtle> and ~mplcmeritat~o~~ of it format in^^ pol~cy wl~i(~li taktas a place hy goverrirnrlit of Japar~ aid arraly~c,.; thi~ ~ I . O I . P S I of deciiioii maltiiig iri polit~cal procedures. So far as b:ast-A\~ari riatioris art, ~ . n r i v t ~ r ~ ~ , e.;pc,ciall\. Kr,rc.an a~rd Japair !rave ,imilar cultural and liistorical backjir. ourii1, ard could t)t. tliif most a p p r o p r i a t ~ ~ caac stlldh for political ~nq~lerncritat~orr. Thus the topic of this artrclc will be useful to r t ~ a l l ~ t . Ore, trail ur~d c r r o r prorex, iri iiiior.matior~ pnlic\ulcorner.

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AlInGaN - based multiple quantum well laser diodes for Blu-ray Disc application

  • O. H. Nam;K. H. Ha;J. S. Kwak;Lee, S.N.;Park, K.K.;T. H. Chang;S. H. Chae;Lee, W.S.;Y. J. Sung;Paek H.S.;Chae J.H.;Sakong T.;Kim, Y.;Park, Y.
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2003.11a
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    • pp.20-20
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    • 2003
  • We developed 30 ㎽-AlInGaN based violet laser diodes. The fabrication procedures of the laser diodes are described as follows. Firstly, GaN layers having very low defect density were grown on sapphire substrates by lateral epitaxial overgrowth method. The typical dislocation density was about 1-3$\times$10$^{6}$ /$\textrm{cm}^2$ at the wing region. Secondly, AlInGaN laser structures were grown on LEO-GaN/sapphire substrates by MOCVD. UV activation method, instead of conventional annealing, was conducted to achieve good p-type conduction. Thirdly, ridge stripe laser structures were fabricated. The cavity mirrors were formed by cleaving method. Three pairs of SiO$_2$ and TiO$_2$ layers were deposited on the rear facet for mirror coating. Lastly, laser diode chips were mounted on AlN submount wafers by epi-down bonding method. The lifetime of the laser diodes was over 10,000 hrs at room temperature under automatic power controlled condition. We expect the performance of the LDs to be improved by the optimization of the growth and fabrication process. The detailed characteristics and important issues of the laser diodes will be discussed at the conference.

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