• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.118.2-118.2
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• 2016

3D NAND 제조에 있어 high-aspect-ratio etch 공정을 견뎌낼 수 있는 hardmask 소재로서 amorphous carbon layer (ACL) 가 각광받고 있으며 hardmask로서의 특성을 향상시키기 위해 다양한 연구가 진행중에 있다 [1]. 본 연구팀의 기존 연구에서 질소 및 붕소 doping 된 ACL 박막의 etch rate 및 Raman 분석을 통해 박막 특성을 확인한 바 있었으나, 공정 중 arcing이 일어나는 등 의도치 않은 문제로 인해 공정 최적화에 일부 문제가 존재하였다. 본 연구에서는 plasma enhanced chemical vapor deposition (PECVD) 공정을 통해 C6H12 기체 및 doping을 위한 NH3 와 B2H6 두 기체를 이용하여 특성 개선된 ACL을 증착하는 과정에서 발생하는 arcing 및 증착 특성을 규명하고자 진공 내 입자의 수농도를 실시간 측정할 수 있는 particle beam mass spectrometer(PBMS)를 적용, 특정 공정 사건 진단 및 해당 사건에서 발생하는 입자를 분석, 증착된 박막의 Raman spectroscopy 결과와 비교 분석하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.247.2-247.2
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• 2016

산업 발달에 따라 여러 유해 가스들의 양이 많아지고 그 종류가 다양해지고 있다. 이에 따라 가스센서의 필요성도 더욱 증가 하였고, 이러한 변화에 대응하기 위해 기존 가스 센서로 이용되던 $SnO_2$나 ZnO보다 더 나은 화학정 안정성과 내구성을 얻고자 2D $MoO_3$ 박막의 대면적 합성을 연구를 진행하였다. 기존 $MoO_3$ 합성에 사용되던 Pyrolysis 방식이 아닌, 플라즈마 화학기상증착법(PECVD)을 이용해 공정과정을 단순화시켜 센서 수율 증대를 목표로 하였다. E-beam avaporator을 이용해 Mo 금속 박막을 $SnO_2$ 기판 위에 증착시킨 후 $O_2$ 플라즈마를 이용한 Implantation 방식으로 박막을 합성하였고, 라만 분광법, X-ray 광전자 분광법(XPS)을 통해 $MoO_3$ 박막이 nm단위로 합성된 것을 확인하였다. 이를 바탕으로 $MoO_3$ 박막을 2D 가스센서의 소재로 적용하는 것이 가능할 것이라고 예상된다.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.70.2-70.2
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• 2015

현재 반도체 및 디스플레이이 공정 분야는 1 um 이상의 입자에서부터 10 nm이하 크기의 오염입자를 제어해야 한다. 현재 오염원인을 파악하기 위해서 사용하는 방법은 공정 완료 후 대상물(웨이퍼 및 글래스)을 CD-SEM (Critical Dimension Scanning Electron Microscope)와 같은 첨단 분석장비를 사용하여 사후 (Ex-situ) 진행하고 있다. 이러한 방법은 오염원이 이미 공정 대상물을 오염시키고 난 후 그 원인을 분석하는 방법으로 그 원인을 찾기가 어려울 뿐만 아니라, 최근 공정관리가 공정 진행 중(In-situ) 행해져야 하는 추세로 봤을 때 합당한 방법이라 할 수 없다. 이를 해결하기 위해 진공공정 중 레이저를 이용하여 측정하고자 하는 여러 시도들이 있었지만, 여전히 긍정적인 답변을 보여주지 못하고 있다. 본 발표에서 소개하는 PCDS (Particle Characteristic Diagonosis System)은 PBMS (Particle Beam Mass Spectrometer)와 SEM (Scanning Electron Microscope), 그리고 EDS (Energy Dispersive X-ray Spectroscopy)를 통합하여 만든 시스템으로 진공공정 중 (In-situ) 챔버 내부에서 발생하고 있는 입자의 크기 분포, 입자의 형상, 그리고 입자의 성분을 실시간으로 분석할 수 있는 방법을 제공한다. 이러한 방법 (PCDS)에 대한 개념과 원리, 그리고 현재까지 개발된 단계에서 얻어진 결과에 대해 소개할 것이다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.3
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• pp.635-643
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• 1998

A spectral element method(SEM) is introduced for the vibration analysis of a rectangular plate subject to dynamic concentrated loads. First, the spectral plate element is derived from the relations between the forces and displacements along the two opposite edges of plate element. The global spectral matrix equation is then formulated by assembling two spectral plate elements so that the dynamic concentrated load is located at the connection nodal line between two plate elements. the concentrated load is then spatially Fourier transformed in the direction of the connection nodal line to transform the two-dimensional plate problem into a simplified equivalent one-dimensional beam-like problem. We may benefit from these procedures in that the spectral results from the present SEM is compared with the exact analytical solutions to prove the remarkable accuracy of the present SEM, while this is not true for conventional finite element solutions, especially at high frequency.

• Progress in Medical Physics
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• v.1 no.1
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• pp.109-122
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• 1990

A method of making inserts for shaped fields in electron beam therapy on the Mevatron KD 67-7467 Linear Acclerator is introduced. The inserts are made from an alloy called Lipowitz metal. These are designed to fit the inside of the standard Siemens cones. Studies have shown that this method does not adversely affect field flatness. However, if the ratio of shaped field to open field is greater than about 70%, the output dose is significantly changed by the inserts. Because the cone ratios for the fields do not follow the open cone ratio curves on the Mevatron KD 67-7467, we separated the cone ratio suggested by Biggs into two parts, the insert ratio and the cone factor. The dosimetry for these shaped beams has been investigated extensively.

• Food Science of Animal Resources
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• v.35 no.2
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• pp.248-257
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• 2015

Effects of double packaging (combinational use of aerobic and vacuum conditions) and antioxidants on physicochemical properties in irradiated restructured chicken rolls were determined. Chicken breast treated with antioxidants (none, sesamol+a-tocopherol) was used to process restructured chicken breast rolls. The sliced rolls were vacuum, aerobic, or double packaged (vacuum for 7 d then aerobic for 3 d) and electron beam irradiated at 2.5 kGy. Color, 2-thiobarbituric acid reactive substances (TBARS), oxidation reduction potentials (ORP), and volatile profiles of the samples were determined at 0 and 10 d. Irradiation made restructured chicken rolls redder (p<0.05), and the increased redness was more distinct in irradiated vacuum-packaged than irradiated aerobic or double packaged meats. TBARS values of antioxidant-treated double packaged rolls were lower than even nonirradiated vacuum-packaged meat, and those were distinct at 10 d (p<0.05). ORP and lipid oxidation values were lower in irradiated vacuum and double packaged samples than those in irradiated aerobic packaged ones at 0 d (p<0.05). Irradiation of restructured chicken rolls increased the amount of total volatiles. Considerable amounts of off-odor volatiles were reduced or not detected by double packaging and antioxidant treatment at 10 d. Therefore, the combined use of antioxidants and double packaging would be useful to reduce redness and control the oxidative quality changes of irradiated restructured chicken rolls

• Journal of the Korea Concrete Institute
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• v.17 no.5 s.89
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• pp.835-842
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• 2005

This paper presents an experimental investigation of bond-strengthening hooks as a new method to increase bond strength along flexural reinforcing bars in reinforced concrete (RC) beams and columns. The RC members, which consisted of 1,300 MPa-class spirals as shear reinforcement, often suffered from bond splitting failure. The proposed method attempts to increase confining stiffness around the flexural bars by placing U-shaped hooks and to prevent premature bond splitting failure. Twelve specimens with varied amounts and sizes of the hooks were prepared to verify the strengthening effectiveness under monotonic and cyclic loading conditions. The test result indicated that the hooks increased the bond strength along the flexural bars although the strengthening effectiveness was limited by effective reinforcement ratio $P_{be}$. This limit is determined by size of stress-transmitting zones of concrete around anchors of the hooks. Anchors of the hooks are recommended to be longer than twelve times the hook diameter and inserted deeper than a quarter of the member depth (D/4). Proposed design equations provide modest estimates of the shear strengths.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.11
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• pp.1027-1036
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• 1991

This paper proposes an implementation of ODIF(Open Document Interchange Format)decoder and PostScript converter. AS ODIF data stream based on IS 8613 is described according to ASN.1 notation it is necessary to decode ODIF data stream to the proper internal structure to PostScript format as proposed in order to make hard copies in good quality using LBP(Laser Beam Printer). Among several kinds of DA(Document Architecture) and DAP(Document Application Profile). PDA(Processable DA) and Core 26(Level 2 DAP) are selected for our study. An ODIF data stream submitted by ICL is used to show the conformance in the level of data stream.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.35.1-35.1
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• 2011

수열합성법으로 제작된 ZnO 나노와이어는 저온 MBE (Molecular Beam Epitaxy) 방식과 달리 Ti, Au와 같은 촉매로 부터 성장이 끝난뒤 나노와이어 끝에 남는 촉매를 제거해야할 필요가 없으며, 저온에서 합성이 가능하기 때문에 현재 연구가 많이 되고 있는 방법중에 하나이다. 본 연구에서는 수열 합성법을 이용하여 금속촉매 또는 AZO로 seed를 형성한 후 기판 위에 균일한 크기의 ZnO 나노막대를 성장시키고 성장밀도 및 길이의 간편한 제어를 하였다. 이를 위해 계면활성제인 PEI (Polyethyleneimine) 첨가 및 Chloride ($Cl_-$)를 조절하여 ZnO 나노와어의 성장밀도를 조절 하고자 하였다. 실험방법으로는 전구체인 Zn(NO3)2${\cdot}$6H2O와 HMT에 Chloride 계열인 Ammonium chloride 와 Kcl 의 몰농도를 각각 조절하고 PEI를 첨가하여, ZnO 나노와이어를 성장하였다. 성장된 ZnO 나노와이어의 특성을 평가하기 위해 field emission scanning electron microscopy (FE-SEM)을 이용하여 광학적인 특성을 측정하였으며, 결정성을 조사하기 위해 X-ray diffraction (XRD)을 이용하여 분석하였다. 또한 scanning PL 장비를 통해 photoluminescence양을 측정하고 ZnO 나노와이어의 응용 가능성을 평가하였다.

• Korean Journal of Optics and Photonics
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• v.11 no.4
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• pp.294-298
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• 2000

The output characteristics of intracavity frequency doubling of laser-diode end-pumped Nd:S-VAP laser were investigated. Nd:S-VAP is suitable for a microchip laser medium, which has a low threshold property because of a very high value of the stimulated emission cross-section and lifetime product. The threshold energy measured was 81 J.ll. The second harmonic output energy measured was $126\mu\textrm{J}$at a pump energy of $2\mu\textrm{J}$. We described for intracavity frequency doubling by using theoretical calculations. Q-switched second harmonic energy measured was $15\mu\textrm{J}$per pulse with a pulse-width of 26 ns. at a pump energy of 2 mJ and an $M^2$ of 1.47 represented a good beam quality. ality.