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UV-LASER INDUCED SURFACE REACTION - DESORppTION AND ETCHING

  • Murata, Yoshitada
    • Proceedings of the Korean Vacuum Society Conference
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    • 1992.02a
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    • pp.3-10
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    • 1992
  • pphotostimulated desorpption of NO chemisorbed on ppt(001) at 80K has been studied by the (1+1)-resonance-enhanced multipphoton ionization((1+1)-REMppI) technique. A linearly ppolarized ArF excimer laser ( =193 nm, 6.41eV) is used as the ppumpp laser. A high adsorpption rate selectivity was found in the expposure deppendence of the NO desorpption yield. The NO desorpption yield increases drastically when the amount of NO expposure exceeds ~1.8 L. This result shows that the amount of NO sppecies with a large cross section for pphotostimulated desorpption increases drastically at higher NO coverages. Using scanning tunneling microscoppy, we have observed structural modifications of the chlorinated Si(111)-7$\times$7 surface induced by 266nm laser irradiation. At very low laser fluence of 0.7mJ/$\textrm{cm}^2$, at which thermal desorpption can be ignored, a pperiodic stripped ppattern of a single domain is imaged. This ppattern consists of flat terraces and narrow grooves of ~60 and ~10A in width, resppectively.

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Structural Properties of SCT Thin Film with Deposition and Annealing Temperature (증착 및 열처리온도에 따른 SCT 박막의 구조적인 특성)

  • Kim, Jin-Sa
    • Journal of the Semiconductor & Display Technology
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    • v.6 no.3
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    • pp.41-45
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    • 2007
  • The (SrCa)$TiO_3$(SCT) thin films were deposited on Pt-coated electrode(Pt/TiN/$SiO_2$/Si) using RF sputtering method according to the deposition condition. The crystallinity of SCT thin films were increased with increase of deposition temperature in the temperature range of $100{\sim}500[^{\circ}C]$. The optimum conditions of RF power and Ar/$O_2$ ratio were 140[W] and 80/20, respectively. Deposition rate of SCT thin films was about $18.75[{\AA}/min]$ at the optimum condition. The composition of SCT thin films deposited on Si substrate is close to stoichiometry (1.081 in A/B ratio). The maximum dielectric constant of SCT thin film was obtained by annealing at $600[^{\circ}C]$.

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Development of a Virtual Reality Application for Helping Self-Directed Learning - Focused on Nonspecific Immunity Learning (자기 주도 학습을 돕는 가상현실 앱 개발 : 1차 방어 작용 학습 중심으로)

  • Kim, Yuri;Lee, Hyunju;Park, Chan Jung
    • Proceedings of The KACE
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    • 2018.08a
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    • pp.41-44
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    • 2018
  • 최근 가상현실의 시대가 다시 각광 받고 있는 시점에서 콘텐츠 확산을 위해 노력하는 것은 의미를 가진다. 본 연구에서는 중학교 과학에서 항상성과 몸의 조절 중 1차 면역 반응을 학습하는데 도움을 줄 수 있는 VR 학습 콘텐츠를 개발하였다. VR 게임으로 구현하여 학습자가 직접 몸속에 들어가 1차 면역 반응을 체험하도록 개발하였다. 학습자의 흥미를 높이기 위해 게임이라는 컨텐츠를 이용하여 학습자가 게임을 하며 학습할 수 있어 자기주도적 학습이 가능하다. 또한 최근 디지털 교과서에서 VR/AR 콘텐츠가 제공되기 시작하여 가상현실 기술의 교육적 활용 가능성을 높이고자 하였다.

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A Study on the Use and Provision of Urban Parks in Kwang Ju City (광주시 도시공원의 이용과 공급에 관한 연구)

  • 오병태
    • Journal of the Korean Institute of Landscape Architecture
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    • v.22 no.4
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    • pp.1-21
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    • 1995
  • Parks in Kwang Ju ar determined by the development of a housing project under the regulations of land development rather than the planning approach of park provision. This study tries to identify who is the provider of parks, to estimate the size of urban parks per person in the area of the housing project, to look at the spatial allocation patterns of park provision and to identify the character profiles of users and the social profile of an ares(Dong). This research has produced the following major conclusions : 1. The city government should set up a master plan of park provision to control park delivery system to avoid maldistribution. 2. A positive discrimination policy should be introduced to disadvantaged areas in terms of park provision. 3. The null hypothesis - there is no relationship between distance and park Use - is rejected by the correlation rate of 0.4984. 4. The ratio of parks per a person ; 10.43㎡/person in 1990 has decreased to 10.41㎡ /person in 1994. This means that the increase of parks in terms of quantity could not catch up the increase of population.

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Comparative Studies on Morphology of Low Temperature Ar-Plasma-treated Polymer Surfaces (알곤저온플라즈마처리된 고분자표면의 모폴로지에 대한 비교연구)

  • Seo Eun-Deock
    • Textile Coloration and Finishing
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    • v.16 no.5
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    • pp.35-41
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    • 2004
  • Poly(ethylene terephthalate), polyimide(Kapton), and polypropylene surfaces were modified with argon low temperature plasma by RF glow discharge at 240m Torr, 40W to investigate the surface morphological changes due to the plasma treatment using atomic force microscopy(AFM). Analysis of the AFM images and Ra(average roughness) revealed that the plasma treatment resulted in significant ablation on the surfaces. The morphological changes and surface roughness, however, were different depending on material characteristics such as heat stability, presence of amorphous region, swelling phenomenon, and molecular structure of repeating unit. It was assumed that polypropylene due to its tertiary hydrogen was ablated easily compared to poly(ethylene terephthalate), and that polyimide was more resistant to the ablation than PET due to rigid skeleton of imide and stable phenyl ring structure.

Ferrite-based wideband circularly polarized microstrip antenna design

  • Mashhadi, Mostafa;Komjani, Nader;Rejaei, Behzad;Ghalibafan, Javad
    • ETRI Journal
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    • v.41 no.3
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    • pp.289-297
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    • 2019
  • In this paper, a wideband, circularly polarized patch antenna is proposed that leverages the unidirectional resonant modes of a circular patch mounted on top of a grounded dielectric-ferrite substrate. The proposed antenna is fed via the proximity coupling method and several parasitically coupled patches are placed on a dielectric superstrate to enhance the impedance bandwidth of the antenna. The resonant modes of the structure rotate only in the clockwise or counter clockwise directions. In the frequency range where the effective permeability of the ferrite layer is negative, the resonance frequencies of these modes differ significantly, which produces a large axial ratio (AR) bandwidth. For the proposed antenna, the numerical results show the 10 dB impedance bandwidth to be around 44% and the 3 dB axial ratio bandwidth to be higher than 64%.

Construction of "CIDEAR" Model for Selecting and Evaluating Cross Impact R & D Projects (상호영향형 R&D과제군의 평가산정을 위한 "CIDEAR" 모형의 개발)

  • Kwon Cheol Shin;Park Joon Ho;Hong Seok Ki
    • Journal of the Korean Operations Research and Management Science Society
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    • v.29 no.3
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    • pp.41-61
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    • 2004
  • The purpose of this paper is to construct $\ulcorner$CIDEAR(Cross Impact-DEA-AR)$\lrcorner$ model which evaluates proposed R&D projects considering cross impact among them and selects proper projects to utilize resources efficiently as well as to maximize efficacy of investments. For this purpose, $\ulcorner$CIDEAR$\lrcorner$ model is designed as the following six steps. $\ulcorner$Decision Theory Evaluation Model$\lrcorner$ is for setting and selecting the evaluation items according to the structured procedure of evaluation system. The priority of items is decided at $\ulcorner$AR Decision Model$\lrcorner$$\ulcorner$Cross Impact Estimation Model$\lrcorner$ is for computing the final probability of success and the result is used to revise the evaluation results of $\ulcorner$Decision Theory Evaluation Model$\lrcorner$. $\ulcorner$Resource Performance Analysis Model$\lrcorner$ classifies the proposed R&D projects on the basis of required resources and expected performance. Consequently, the possibility of bias of project selection can be prevented. $\ulcorner$Priority Oder Decision Model$\lrcorner$ is for computing the efficacy of proposed projects. Finally, $\ulcorner$Efficacy-Efficiency Cause Analysis Model$\lrcorner$ analyzes the structure of efficacy and efficiency of the projects. The major findings and significances of this study are summarized as follows: (1) $\ulcorner$CIDEAR$\lrcorner$ model can deal with the affairs of R&D projects having the characteristics of mutual independence as well as mutual dependence in the point of efficacy and efficiency. Hence, it is possible to evaluate and select R&D projects more accurately. (2) It can be possible to raise the possibility of projects success. R&D manager can use the information for project management because the efficacy-efficiency structure of selected projects can be analyzed. (3) We proved the usefulness of the constructed $\ulcorner$CIDEAR$\lrcorner$ model using an case about twenty-one R&D projects of a leading company of electronic industry in Korea.

The Effect of Reinforcing Soil Shear Strength by a Root System Developed from Direct Sticking of Salix gracilistyla Miq (삽목에 의한 갯버들 근계의 토양전단강도 보강효과)

  • 이춘석;임승빈
    • Journal of the Korean Institute of Landscape Architecture
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    • v.31 no.5
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    • pp.1-10
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    • 2003
  • The purpose of this study was to verify the shore margin protection effect of a root system developed from direct sticking of Salix gracilistyla Miq., focusing on the reinforcement of soil shear strength. The materials were 20cm long sticks whose average diameter and weight were 7.52mm and 14.58g respectively, and sandy loam(Sand 60.36%, Silt 28%, Clay 11.64%), whose maximum dry weight(${\gamma}$$_{dmax}$) was 1.59gf/㎤ at the water ratio( $W_{opt}$) 13.8%. The direct shearing test(KS F 2343) was applied to cylindric columms(diameter 132mm) of pure soil and two years old root reinforced soil. At each condition of vertical stress, 10N/$ extrm{cm}^2$, 14.41N/$\textrm{cm}^2$ and 18.82 N/$\textrm{cm}^2$, five soil+root columns were sheared. After shear tests, the root area ratio and soil moisture on the shear plane were measured. The results of this research were as follows: 1. The average of root area ratio was 1.86% and the soil moisture 14.67%. 2. Two years old root system was found to increase the soil shear strength of pure soil in terms of Cohesion(C) and Inner friction Angle($\phi$) as follows. 3. The relationship between root area ratio and the increased shear strength can be presented with the following equation, $\Delta$S ≒ 0.33ㆍ TrㆍAs/A $\Delta$S : Increased Shear Strength Tr : Average Tension Strength of Root, Ar/A : Root Area Ratioioage Tension Strength of Root, Ar/A : Root Area Ratio

A Study on Development of Interactive Contents for Digital Mirror (Digital Mirror를 위한 인터렉티브 콘텐츠 개발에 관한 연구)

  • Lee, Ki-Hoon;Jeong, Ji-Hong;Pan, Young-Hwan;Oh, Sung-Ryong;Park, Jin-Woo;Jo, Hyun-Cheol;Lee, Dong-Wook
    • 한국HCI학회:학술대회논문집
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    • 2008.02b
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    • pp.41-46
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    • 2008
  • 디지털 기술의 발전은 인간 생활에 큰 변화를 가져다주었다. 이와 같은 디지털 기술의 발전으로 변화된 인간 생활 중 가장 큰 변화는 기술의 발전 이전에 사용되던 각종 제품 및 도구들이 디지털 기술의 힘으로 새롭게 재탄생하고 있다는 점이다. 재탄생된 제품 및 도구들은 사람과 제품간의 경계를 무너뜨리고 서로 융합되고 있다. 이러한 제품들 중에서 대표적으로 Digital Mirror를 들 수 있다. 기존 인간 생활에서 사용되던 일반적인 Mirror가 최근 들어 Digital Mirror라는 새로운 형태의 제품으로 연구되어 지고 있다. 이러한 Digital Mirror는 일상생활 속에서 기존 거울을 대체하고 있으며, 인터렉티브 미디어 아트에서도 많이 응용되고 있다. 현재 Digital Mirror는 광고, 인터렉티브 아트 등의 분야에서 다양한 형태의 콘텐츠가 개발되고 있다. 하지만 Digital Mirror를 새로운 제품 산업군으로 확대하여 신사업을 창출하기 위해서는 수많음 사용자들의 욕구를 충족시킬 수 있는 인터렉티브한 콘텐츠 제작을 해야 한다. 본 연구에서는 Digital Mirror의 인터렉티브한 콘텐츠 제작을 목적으로, 기존의 인터렉티브한 콘텐츠 사례를 중점적으로 연구하여 새로운 콘텐츠 아이디어를 도출하였다. 아이디어를 통해 어린이 사용자를 타켓으로 새로운 사용경험을 제공해 줄 수 있는 컨셉을 정하여 인기 애니메이션 캐릭터를 사실적으로 체험할 수 있게 해주는 콘텐츠 제작방향을 설정하여 연구를 진행하였다. 또한 놀이와 참여, 상호작용을 통한 새로운 디지털 놀이 도구라는 개념으로 AR기술을 이용해 캐릭터를 좀더 사실적으로 체험 할 수 있도록 제작하였다. 어린이 사용자가 캐릭터 마커를 착용하고 Digital Mirror앞에 서게 되면 캐릭터 마커에 해당되는 3차원 입체영상 애니메이션 캐릭터가 어린이 사용자의 모습과 합성되어 사실적인 캐릭터 콘텐츠를 체험 할 수 있게 해 주는 콘텐츠이다. 어린이들에게 인기 있는 캐릭터를 3D로 제작하여 캐릭터 소스로 활용하였고 이를 효율적으로 사용할 수 있도록 어플리케이션 저작툴을 개발 완료하여 제작하였다. 그리고 평판 디스플레이를 이용하여 실제 Prototype 제작하였다.

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Hydrothermal Synthesis of Ultra-fine SrAl2O4:Eu Powders and Investigation of their Photoluminescent Characteristics (수열합성법에 의한 SrAl2O4:Eu 초미세 분말 합성공정 및 형광 특성)

  • 박우식;김선재;김정식
    • Journal of the Korean Ceramic Society
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    • v.41 no.5
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    • pp.370-374
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    • 2004
  • Sr$_{l-x}$Ba$_{x}$Al$_2$O$_4$:Eu (x = 0, 0.1, 0.2, and 0.3 mol) phosphor was synthesized by the hydrothermal method and its properties of photoluminescence and long-afterglow were investigated. The mixtures of Sr(NO$_3$)$_2$, Al(NO$_3$)$_3$9$H_2O$, and Eu(NO$_3$)$_3$$.$6$H_2O$ salts dissolved in distilled water, after controlling their pH by NH$_4$OH solution, put into an Autoclave reactor with high temperature and pressure to react. Such synthesized SrAl$_2$O$_4$:Eu powders showed homogeneous and ultra-fine particles of sub-micron size. In order to have the photoluminescence characteristic, powders were heat treated at 1100 -140$0^{\circ}C$ for 2 h in Ar/H$_2$ reduction atmosphere. Photoluminescence spectra showed a excitation along the wide wavelength of 250 ∼ 450 nm, and broaden emission with maxima peak at 520 nm. Also, it showed a good long afterglow with decaying over 1000 sec after excitation illumination for 10 min. In addition, the microstructure and crystal structure of SrAl$_2$O$_4$:Eu powders were investigated by an SEM and XRD, respectively.