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Plasma Assisted Nitriding of Stainless Steel Type 304L (304L 스테인리스 강의 플라즈마 질화처리)

  • Park, J.R.
    • Journal of the Korean Society for Heat Treatment
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    • v.8 no.4
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    • pp.255-265
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    • 1995
  • Stainless steel type 304L has been nitrided in the low pressure (600Pa) and high nitrogen (80% $N_2$+20% $H_2$) environment for 5 hours by the square-wave-pulsed-d.c. plasma as a function of temperature $400{\sim}550^{\circ}C$ and pulsation. At the lower temperature range of $400{\sim}500^{\circ}C$ and at the relatively high ratio of pulse duration to pulse period. "S-phase" has been developed in the form of thin nitrided surface layer which has many cracks, leading to be nearly impossible for the industrial anti-wear and anti-corrosion applications. At the higher temperature up to $550^{\circ}C$ with the increasing ratio of the pulse duration to pulse period up to $50{\mu}s/100{\mu}s$, the nitrided layer, whose growth rate has increased also, has been composed mainly of CrN and $Fe_4N$ phases and has become thick, uniform and nearly crack-free.

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D$\acute{e}$veloppement d'un Programme d'$\acute{E}$cotourisme dans la R$\acute{e}$gion de Yeosu en Coree du Sud: le Cas de l'$\hat{I}$le de Sado et de son Relief Caract$\acute{e}$ristique (지형 특성에 기반한 여수시 사도일원의 생태관광 프로그램 구성)

  • Lee, Jeong-Hun
    • Journal of the Korean association of regional geographers
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    • v.17 no.6
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    • pp.738-752
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    • 2011
  • La c$\hat{o}$te m$\acute{e}$ridionale de la Cor$\acute{e}$e du sud, et principalement la ville de Yeosu et ses environs pr$\acute{e}$sentent un int$\acute{e}$r$\hat{e}$t particulier puisque le paysage offre de nombreuses presqu'$\hat{i}$les, baies et $\hat{i}$les. Pour tirer profit de ces paysages naturels il est d'abord n$\acute{e}$ssaire de les prot$\acute{e}$ger. Malgr$\acute{e}$ la haute valeur de ces paysages naturels, ils demeurent peu connus et les analyses $\acute{e}$cotouristiques de la ville de Yeosu et ses environs sont encore incompl$\grave{e}$tes. Par ailleurs, la protection de ces paysages naturels est rendue difficile par la d$\acute{e}$sagr$\acute{e}$gation d$\hat{u}$e aux sels halo$\ddot{i}$des. Cette recherche a pour objet l'$\acute{e}$tude du tourisme physico-$\acute{e}$cologique et sa contribution au d$\acute{e}$veloppement $\acute{e}$conomique d'une r$\acute{e}$gion de Yeosu en Cor$\acute{e}$e du sud. Nous nous int$\acute{e}$ressons particuli$\grave{e}$rement au d$\acute{e}$veloppement d'une route $\acute{e}$cotouristique, aux crit$\grave{e}$res de s$\acute{e}$lection du lieu $\acute{e}$cotouristique et $\grave{a}$ la pr$\acute{e}$sentation des explications touristiques, en tenant compte de l'$\hat{i}$le de Sado et de ses paysages naturels sur le plan de l'$\acute{e}$cotourisme. Il y a plusieurs ressources $\acute{e}$cotouristiques sur l'$\hat{i}$le de Sado et dans ses environs: la plage de sable et la falaise de l'$\hat{i}$le de Sado; les traces fossiles de dinosaures, la ripple-mark et la crevasse dans le sol boueux de l'$\hat{i}$le de Joungdo; le tombolo, l'affleurement tufac$\acute{e}$ et le dyke de l'$\hat{i}$le de Silouseom; le trou provoqu$\acute{e}$ par les sels halo$\ddot{i}$des et le dyke de l'$\hat{i}$le de Jangsado; la mer ass$\acute{e}$ch$\acute{e}$e entre l'$\hat{i}$le de Naquek et l'$\hat{i}$le de Choudo. On a, g$\acute{e}$n$\acute{e}$ralement, d$\acute{e}$velopp$\acute{e}$ les reliefs li$\acute{e}$s $\grave{a}$ la couche s$\acute{e}$dimentaire et les fossiles de la derni$\grave{e}$re p$\acute{e}$riode du m$\acute{e}$sozo$\ddot{i}$que. La route $\acute{e}$cotouristique part de l'embarcad$\grave{e}$re de l'$\hat{i}$le de Sado et continue du Nord jusqu'au Sud.

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Synthetic Studies on Carbapenam Skeletons

  • 구양모;서민효;이윤영
    • Bulletin of the Korean Chemical Society
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    • v.17 no.10
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    • pp.909-918
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    • 1996
  • Syntheses of carbapenam skeletons were achieved from 1,3-propanediol through 1,3-dipolar cycloaddition. 3-(Tetrahydropyran-2-yloxy)-(10) and 3-(t-butyldimethylsilyloxy) propanal (13) were obtained from 1,3-propanediol. 3-Hydroxypropanals (10, 13, 14) were reacted with N-hydroxyglycine esters to give C-(2-hydroxyethyl)-N-alkoxycarbonylmethylnitrones (15a-15d). 1,3-Dipolar cycloaddition of the nitrones with methyl acrylate or ethyl crotonate gave 3-(2-hydroxyethyl)isoxazolidines (16a-16b, 17a-17b, 18, 19a-19b). 3-(2-Hydroxyethyl)isoxazolidines (17a, 17c, 19a, 19b) were converted to 3-(2-iodoethyl)isoxazolidines (21a-21d) or 3-phenylthiocarbonylmethylisoxazolidines (25a-25d) which were cyclized to give 2-oxa-1-azabicyclo[3.3.0]octanedicarboxylates (22a-22d, 26a-26d). 2-Oxa-1-azabicyclo[3.3.0]octane-4,8-dicarboxylates (22c-22d, 26c-26d) were transformed to 6-(l-hydroxyethyl)carbapenam-3-carboxylates (30a-30b, 31a-31b).

Effents of Plant Explant Position of Miscanthus and Medium Supplements on Callus Induction (억새(Miscanthus spp.) 식물재료와 배지 첨가물질이 캘러스 형성에 미치는 영향)

  • Kim, Kwang-Soo;Kwon, Da-Eun;Lee, Ji-Eun;Cha, Young-Lok;Moon, Youn-Ho;Song, Yeon-Sang;Kang, Yong-Ku
    • Proceedings of the Plant Resources Society of Korea Conference
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    • 2018.04a
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    • pp.54-54
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    • 2018
  • 억새(Miscanthus spp.)는 우리나라 등 동아시아가 원산이며 바이오매스량이 많아 바이오에너지 원료작물로서 잠재성이 크기 때문에 2세대 바이오에탄올 생산 원료로 주목을 받고 있고, 축산깔개 및 토양개량제 등으로도 이용되고 있다. 미국과 유럽 등에서는 생태계 교란 방지를 위해 4배체 물억새(M. sacchariflorus)와 2배체 참억새(M. sinensis)의 종간 교잡 이질 3배체인 불임성 억새(M. x giganteous)을 주로 재배하고 있으나, 단일 유전형의 품종으로 병해충과 자연재해에 취약하여 다양한 억새 품종의 개발이 시급한 실정이다. 본 연구는 억새를 재료로 하여 반수체 및 배수체 확보를 통한 배수성 별 특성 평가와 함께 기내배양을 통해 탈분화 및 재분화 시스템을 구축하여 억새의 육종 효율을 높이기 위해서 실시하였다. 억새 종자로부터 캘러스의 유도는 MS배지와 N6배지에 1mg/L 2.4-D를 첨가하였을 때 비배발생 캘러스(nonembryogenic callus)가 유도되었고, N6배지에 3~5 mg/L 2,4-D를 첨가하였을 때 배발생 캘러스(embryogenic callus)가 발생하였다. MS배지보다는 N6배지에서 캘러스 유도율이 높았으며, 식물생장조절제로 2,4-D와 BA 조합처리 보다 2,4-D 단용 처리하였을 때 캘러스 유도율이 더 높았다. 억새 종에 따른 캘러스 유도율은 물억새가 25.2~49.3%, 참억새는 30.3~52.0%였고 거대억새는 62.6~81.1%로 나타났다. 억새 신초 및 줄기로부터의 캘러스 유도율은 물억새가 4.4~17.2%, 참억새는 1.8~7.7%, 거대억새는 15.3~19.9%로 나타나 종자에 비해 매우 낮았다. 미성숙화기로부터의 캘러스 유도는 억새 종에 따른 차이가 없었으며, 3mg/L 2,4-D 첨가 배지에서 캘러스 유도율이 비교적 낮았고(60~80%), 1mg/L와 5mg/L의 2,4-D가 첨가된 배지에서 캘러스 유도율이 높게(90~95%) 나타났다.

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LAGUERRE CHARACTERIZATIONS OF HYPERSURFACES IN ℝn

  • Shu, Shichang;Li, Yanyan
    • Bulletin of the Korean Mathematical Society
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    • v.50 no.6
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    • pp.1781-1797
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    • 2013
  • Let x : $M{\rightarrow}\mathbb{R}^n$ be an n - 1-dimensional hypersurface in $\mathbb{R}^n$, L be the Laguerre Blaschke tensor, B be the Laguerre second fundamental form and $D=L+{\lambda}B$ be the Laguerre para-Blaschke tensor of the immersion x, where ${\lambda}$ is a constant. The aim of this article is to study Laguerre Blaschke isoparametric hypersurfaces and Laguerre para-Blaschke isoparametric hypersurfaces in $\mathbb{R}^n$ with three distinct Laguerre principal curvatures one of which is simple. We obtain some classification results of such isoparametric hypersurfaces.

Comparison of Effects of Hemoglobin Levels Upon Tumor Response among Cervical Carcinoma Patients Undergoing Accelerated Hyperfractionated Radiotherapy versus Cisplatin Chemoradiotherapy

  • Thakur, Priyanka;Seam, Rajeev Kumar;Gupta, Manoj Kumar;Rastogi, Madhup;Gupta, Manish;Bhattacharyya, Tapesh;Sharma, Mukesh;Revannasiddaiah, Swaroop
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.10
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    • pp.4285-4289
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    • 2015
  • Purpose: Blood hemoglobin levels are known to influence response to radiotherapy. This retrospective analysis compared the effect of hemoglobin levels upon response to radiation among patients treated with radiation alone (by accelerated hyperfractionated radiotherapy) versus those treated with concurrent cisplatin chemoradiotherapy. Materials and Methods: Among patients treated for locally advanced carcinoma of the cervix (LACC) during 2009-10, a total of 60 fulfilled the eligibility criteria. In this time frame, external beam radiotherapy was delivered with either concurrent chemoradiotherapy (CRT, n=31) (45Gy over 25 fractions, with weekly cisplatin at 40mg/m2), or with accelerated hyperfractionated radiotherapy (AHRT, n=29) (20Gy over 10 daily fractions over the first two weeks, followed by 30Gy over 20 fractions over the next two weeks, with two fractions of 1.5Gy per day, without the use of chemotherapy). Mean weekly hemoglobin (MWH) levels of all patients were calculated as the arithmetic means of weekly recorded blood hemoglobin levels. As per MWH, patients in both of the AHRT or the CRT groups were classified into two subgroups-those with MWH between 10-10.9g/dL, or with MWH>11g/dL. Complete response (CR) to external beam RT phase (prior to brachytherapy) was declared after clinical examinations and computed tomography. The CR rate was noted for both MWH sub-groups within each of the AHRT and CRT groups. Results: Within the AHRT group, patients with MWH>11g/dL had a much better CR rate in comparison to those with MWH:10-10.9g/dL (80% vs. 21.1%) which was statistically significant (p 0.0045). Within the CRT group, there was no significant difference in the outcomes within the MWH>11g/dL and MWH:10-10.9g/dL sub-groups (CR rates of 80% vs. 61.9%, p=0.4285). Conclusions: The importance of maintaining a minimum hemoglobin level of 11g/dL during RT is much greater for patients treated with RT alone, than for patients treated with concurrent chemoradiotherapy. Enhanced haemoglobin levels during RT may to an extent negate the ill-effects that may otherwise arise due to non-use of concurrent chemotherapy.

Synthesis and Antifungal Evaluation of 6-(N-arylamino)-7-methylthio-5,8-quinolinediones

  • Kim, Chung-Kyu;Choi, Jung-Ah;Kim, Sung-Hee
    • Archives of Pharmacal Research
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    • v.21 no.4
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    • pp.440-444
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    • 1998
  • A series of 6-(N-arylamino)-7-methylthio-5,8-quinolinedione derivatives 4a-4l was newly synthesized for the evaluation of antifungal activity. 6-(N-Arylamino)-7-methylthio-5,8-quinolinediones were prepared by regioselective nucleophilic substitution of 6,7-dichloro-5,8-quinolinediones with arylamines in the presence of $Ce^{3+}$, and $Na_2$S/dimethylsulfate. The MIC values of 4a-4l were determined for antifungal susceptibility in vitro against Candida species by agar streak method. The derivatives 4a-4l had generally potent antifungal activities against all human pathogenic fungi. Especially they had the most potent activity against C. krusei at 12.5-0.8 $\mu\textrm{g}$/ml. Compounds 4d, 4g, 4h, 4j and 4k had more potent antifungal activities than fluconazole. Compounds 4g and 4h completely inhibited the fungal growth at 0.8-6.3 $\mu\textrm{g}$/ml against all Candida species, while fluconazole inhibited the growth at 25 $\mu\textrm{g}$/ml. The compounds such as 4g and 4h containing an N-(4-bromo-2-methylphenyl)- or N-(4-bromo-3methylphenyl)amino substituent exhibited the most potent antifungal activities.

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Piezoelectric properties of Pb(Sb,Mn) $O_3$- Pb(Zr,Ti) $O_3$ Ceramics doped L $u_2$ $O_3$ (L $u_2$ $O_3$ 치환에 따른 Pb(Sb,Mn) $O_3$-Pb(Zr,Ti) $O_3$ 세라믹스의 압전특성)

  • ;;Sergey Kucheiko
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1997.11a
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    • pp.60-63
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    • 1997
  • Dieletric ailed piezoelectric properties of Pb[$Zr_{0.45}$/ $Ti_{0.5-x}$/L $u_{x}$ (M $n_{1}$3//S $b_{2}$3)$_{0.05}$] $O_3$(0$\leq$x $\leq$0.03) were investigated. The partial substitution of $Ti^{4+}$ by a L $u^{3+}$ permitted improvement of the piezoelectric constant( $d_{33}$ ), electromechanical coupling factor ( $k_{p}$ ) and dielectric constant($\varepsilon$$_{33}$ /Sup T/). The dielectric loss(tan $\delta$ ) increased and mechanical quality factor(Qm) decreased with an increase of x were observed. A new piezoelectric material for actuator application was developed at x=0.02 with $d_{33}$ =370$\times$10$^{-2}$ /C/N, $k_{p}$ =58.5%, $\varepsilon$$_{33}$ $^{T}$ =1321, $Q_{m}$ =714 and tan $\delta$ =0.98%.%..%.%.

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Etude sur le v tement dans le Proche-Orient (근동지역의 복식 연구(I) -성서에서의 복식의 상징성과 고대 근동지역의 복식 연구-)

  • 오춘자
    • Journal of the Korean Society of Costume
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    • v.19
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    • pp.175-194
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    • 1992
  • Le Proche-Orient est le pays de la Bible, Le peuple He breu ancien, appartenant la race des S mits s mi-nomades, est venu avec Abraham, de m sopotamie en Palestine, terre de Canaan. Nous avons consid r les v tements du peuple des anciens H breux en nous basant sur la Bible et en observant des peintures murales et des bas-reliefs des divers payes de l'ancienne poque, Pour comprendre l' volution des v tements des gens de la pr sente r gion palestinienne, nous avons tudi les v tements traditionnels de la race b douine qui m nent jusqu' maintenant une vie nomade dans le m nent jusqu' maintenant une vie nomade dans le d sert, parce que nous n'avons pas pu connaitre le processus d' volution des v tements apr s l'ancienne poque la suite d' v nements historiques compliques. En conclusion, nous pouvons nous r sumer comme suit: 1) Nous pensons que la kimlah, costume important du peuple h breu ancien est devenu abajeh, manteau des B douins, puisque ces v tements servent prot ger le corps lors des changments de temps, et la nuit on les utilise comme couverture et comme sac pour y mettre des objets, et comme tente lors su travail. en un mot, les fonctions de la Simlah et celles de l'abajeh sont les memes l' poque ancienne et maintenant. 2) Nous pensons que la forme et l'utilisation de la Kethoneth ayant une forme de tunique et de la thob des B douins sont presque semblable. La kethoneth et la thob sont la tuniqu importante que portent jusqu' maintenant tous les peuples du Proche-Orient. 3) Comme on le voit dans la Bible, les femmes du peuple h breu et celles des B douins utilisent le voile pour couvrir la e te, et se servent d'accessoires pour d corer leur corps. A l'avenir, les vVtements des Palestiniens, dans une recherche pous approfondie, feront l'objet de a 2 me partie de l' tude des costumes du Proche-Orient.

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