• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.617-617
• /
• 2013

최근 그래핀 연구와 더불어 2차원 구조의 나노소재에 대한 관심이 급증하면서 육각형의 질화붕소(hexagonal boron nitride; h-BN) 박막(nanosheet) [1]이나 붕소 탄화질화물(boron caronitride; BCN) 박막 [2,3]과 같은 2차원 구조체에 대한 연구가 활발히 진행되고 있다. 그 중 BCN은 반금속(semimetal)인 흑연(graphite)과 절연체인 h-BN이 결합된 박막으로 원소의 구성 비율에 따라 전기적 특성을 제어할 수 있다는 장점이 있다. 따라서 다양한 나노소자로의 응용을 위한 연구가 활발히 진행되고 있다. 본 연구에서는 폴리스틸렌(polystyrene, PS)과 보레인 암모니아(borane ammonia)를 고체 소스로 이용하여 열화학기상증착법으로 BCN 박막을 SiO2 기판 위에 직접 합성하였다. SEM과 AFM 관측을 통해 합성된 BCN 박막의 두께가 약 10 nm이며, RMS roughness가 0.5~2.6 nm로 매우 낮은 것을 확인하였다. 합성과정에서 PS의 양을 조절하여 BCN 박막의 탄소의 밀도를 성공적으로 제어하였으며, 이에 따라 전기적인 특성이 제어되는 양상을 확인하였다. 또한 합성온도 변화에 따른 BCN 박막의 전기적인 특성이 제어되는 양상을 확인하였다. 추가적으로 같은 방법을 이용하여 BCN 박막을 Cu 위에서 합성하여 SiO2 기판위에 전사하였다. 합성된 BCN 박막의 구조적 특징과 화학적 조성 및 결합 상태를 투과전자현미경(transmission electron microscopy), X-선 광전자 분광법(X-ray photoelectron spectroscopy), 라만 분광법(Raman spectroscopy)을 통해 조사하였고, 이온성 용액법(ionic liquid) [4]을 이용하여 전계효과 특성을 측정하였다.

• Korean Journal of Optics and Photonics
• /
• v.13 no.3
• /
• pp.223-227
• /
• 2002

Polymeric multi-mode optical waveguides were fabricated for parallel optical interconnection. Waveguide structures were molded by a Ni mold master using a hot embossing technique. The Ni mold master was manufactured by LIGA process. Multimode optical waveguides with a 48$\times$47 ${\mu}{\textrm}{m}$$^2$cross-section were produced by a simple two-step process. The propagation losses of the multimode waveguide measured at 0.85 ${\mu}{\textrm}{m}$ and 1.3 ${\mu}{\textrm}{m}$ wavelengths were 0.38 dB/cm and 0.66 dB/cm, respectively.

• Polymer(Korea)
• /
• v.35 no.1
• /
• pp.77-86
• /
• 2011

Polymerization properties of six dinuclear constrained geometry catalysts (DCGC) were investigated. The different length bridges of three catalysts were para-phenyl (Catalyst 1), para-xylyl (Catalyst 2), and para-diethylene phenyl (Catalyst 6). The other three DCGC have the same para-xylyl bridge with the different substituents at the phenyl ring of the bridge. The selected substituents were isopropyl (Catalyst 3), n-hexyl (Cataylst 4), and n-octyl (Catalyst 5), It was found that the longer catalyst not only exhibited a greater activity but also prepared a higher molecular weight copolymer. The catalyst 3 having a bulky isopropyl substituent revealed the lower activity but formed the highest molecular weight polymer comparing with the other alkyl substituted DCGCs. These results were able to be understood on the basis of the electronic and steric characteristics of the bridge. This study confirms that the control of the bridge structure of DCGC may contribute to control the microstructure of polymers.

• Journal of Korean Ophthalmic Optics Society
• /
• v.11 no.3
• /
• pp.281-291
• /
• 2006

The aim of this study was performed the clinical test using Netspeg lens for good visual acuity on subjects with abnormal refraction status. The subjects of one hundreds adults (fifty males, fifty females, mean=21 years, range=19 to 24) were recorded. The subjects were researched the history including the systemic health, medication, genetics, allergy, systemic disease and ocular disease. The refraction test was recorded the monocular and binocular using objective method. Visual acuity was performed the binocular status using the Netspeg lens and CR-39. Stereopsis test was performed the titmus fly and TNO at near distance using Netspeg lens and CR-39. The P-VEP test was used the 16 pattern size(Bausch Lomb, production in USA) with three channels. Also Subjects viewed the p-vep stimulus with binocular vision through the corrected visual acuity using the Netspeg lens and CR-39. The contrast sensitivity test was performed the contrast sensitivity chart(pelli-Robertson, USA) at 1m distance using the Netspeg lens and CR-39. The ultrastructure of surface on the Netspeg lens and CR-39 was observed the SEM(JMS-5800, made in Japan). The results of this study was as follows: 1. In corrected visual acuity of abnormal refraction using the Netspeg lens and CR-39, the Netspeg lens wearer were acquired the good visual field and clear visual acuity comparative to CR-39 wearer in the subject vision test. however the comfort of visual acuity was similar results in the Netspeg lens and CR-39. Also the subjects of Netspeg lens wearer was good visual acuity more than CR-39 wearer and in the analysis of P-VEP, the amplitude of wave on Netspeg lens used appears to be better through the CR-39(p>0.5). Besides, on the contrast sensitivity, the Netspeg lens wearer was good results than CR-39. The value on stereopsis with TNO by Netspeg lens wearer was better than CR-39 in results. However, in the stereopsis test with Titmus, the Netspeg lens and CR-39 wearer was similar results. 2. The ultrastructure of Netspeg lens surface was the smooth and fine shape more than CR-39. Also, Netspeg lens have a fine line structure in ultrastructure. In conclusion, the results of this study conformed that the surface ultrastructure of Netspeg lens used is more specific pin hole design structure than CR-39. This study indicated that the vision of Netspeg lens used have a better than CR-39 in the corrected visual acuity for abnormal refraction eye. Therefore, In this paper, we suggested that the ultrastructure and line structure of Netspeg lens was related to good visual function. However the visual function of the aspheric Netspeg and ultra waterproof Netspeg lens was similar results.

• Journal of Digital Contents Society
• /
• v.15 no.4
• /
• pp.501-512
• /
• 2014

Due to smart phones introduced since 2007, mobile contents production become activated and with this trend, attention among different age groups to production of mobile games has been growing. Whereas in the past, development of games was the domain of developers equipped with technical knowledge, provision of editor-type engines in recent times is lowering the high barrier of entry to game production. This paper proposes an event-based module design method from the perspective of general users, aimed at producing games by oneself with a Unity 3D, one of editor-type game engines. This is to plan behaviors and roles in the unit of modules in the whole process of a game to be in line with the perspective of game production by one person. Each module includes diverse events that express game characteristics. In addition, the script function provided by the Unity 3D is appropriate to embody the proposed module structure and utilizes the Unity 3D. Lastly, this study produce a simple 3D mobile casual game in order to verify whether effective game production from the planning to the development is possible through the proposed method.

• KDI Journal of Economic Policy
• /
• v.9 no.1
• /
• pp.27-42
• /
• 1987

본논문(本論文)에서는 우리나라의 노동시장(勞動市場)의 구조(構造)를 동학적(動學的)으로 살펴보고 이에 따른 정책과제(政策課題)를 도출(導出)하기 위해 취업(就業)과 실업상태(失業狀態)를 번갈아 움직이는 노동자(勞動者) 행태(行態)의 결정요인(決定要因)을 실증분석(實證分析)하였다. 분석방법(分析方法)으로는 직업탐색이론(職業探索理論)을 이용(利用)하여 이론적(理論的)인 가설(假說)을 도출(導出)하였고, 계량적(計量的) 검증(檢證)을 위해 회귀모형(回歸模型)을 정형화(定型化)하였다. 통계자료(統計資料)는 1985년(年) 한해 동안의 "경제활동인구조사(經濟活動人口調査)"의 매월(每月) "테이프"에서 같은 근로자(勤勞者)를 11개월(個月) 동안 추적하여 분석(分析)을 위한 표본(標本)으로 이용(利用)하였다. 임금(賃金)은 취업(就業)에서 실업(失業)으로 변화(變化)할 확률(確率)에 대해 부(負)의 효과(效果)를 보이고 실업(失業)에서 벗어나 재취업(再就業)할 확률(確率)에도 부(負)의 효과(效果)를 나타내어 이론(理論)에서 도출(導出)된 가설(假設)이 검증(檢證)되었다. 연령(年齡)이 상태간(狀態間) 이동(移動)에 미친 효과(效果)는 부(負)의 값을 보였다. 그러나 이 효과(效果)는 일정한 연령(年齡)이 지나면 정(正)의 효과(效果)로 바뀌는 비선형성(非線型性)을 보였다. 이러한 결과(結果)에 입각(立脚)하여 우리는 높은 임금(賃金)을 받는 근로자(勤勞者)일수록 이직(移職)의 가능성(可能性)이 낮고 또한 실업상태(失業狀態)에서 재취직(再就職)의 가능성(可能性)이 낮다는 사실(事實) 등을 알 수 있다. 이에 따른 정책적(政策的) 시사점(示唆點)의 하나는 직업훈련(職業訓鍊)을 단순히 양적(量的)으로 확대(擴大)하기보다는 연령체계(年齡體系)에 맞추어 그 내용을 질적(質的)으로 조정(調整)하는 것이 바람직하다는 것이다.

• The Korean Journal of Emergency Medical Services
• /
• v.23 no.2
• /
• pp.109-123
• /
• 2019

Purpose: This study aimed to propose an effective one-rescuer infant cardiopulmonary resuscitation (CPR) chest compression technique by comparing the differences in efficacy, convenience, and pain levels between the two thumb-encircling and two finger techniques. Methods: Subjects were randomized to perform either two-thumb-encircling or two-finger technique for 8 minutes each on infant CPR manikins. After the chest compression, a survey was administered to the subjects to measure convenience and pain levels according to compression method. Results: Total compression depth over 8 minutes was significantly deeper for the two-thum-encircling technique ($43.5{\pm}4.8mm$) compared with the two-finger technique ($32.6{\pm}5.4mm$) (p<0.001). In terms of compression depth measured at 1-minute intervals, compression depth with the two-finger technique decreased from $38.3{\pm}4.23mm$ to $29.0{\pm}6.79mm$, whereas compression depth with the two-thumb-encircling technique did not show a significant change (from $43.7{\pm}4.12mm$ to $43.4{\pm}5mm$). The results of the survey indicated that, the majority of subjects found the two-thumb-encircling technique to be the most comfortable technique for compression depth (n=29, 64.4%). The majority of subjects (n=31, 68.9%) answered that the two-finger technique resulted in the most pain. Conclusion: Comparison of efficacy of the two-thumb-encircling and two-finger-techniques in the performance of one-rescuer infant CPR revealed that the two-thumb-encircling technique was more effective in maintaining chest compression depth.

• Journal of the Korean Chemical Society
• /
• v.32 no.4
• /
• pp.297-300
• /
• 1988

Ammonium p-methylbenzenesulfonate, $C_7H_11NO_3S$, Mr = 189.23, orthorhombic, space group $Pna2-1$, a = 20.406(4), b = 6.271(1), c = 7.067(2)${\AA}$, V = 904.19 ${\AA}^3$, Z = 4, $D_x$ = 1.39, $D_m =1.38g{\cdot}cm^{-3}$, ${\lambda}(M_o K_{\alpha})$ = 0. 71069 ${\AA}$, ${\mu}=3.1 cm^{-1}$, T = 298K, F(000) = 400, final R = 0.057 for 994 unique observed reflections with I > $16{\sigma}(I)$. The methylbenzene portion including the sulfur atom is nearly planar. Between the $SO_3$ groups and the ammonium ion, there are three unique hydrogen bonds; two of which make the anions linked along the c-axis and the remaining one along the b-axis. These hydrogen bonds make two-dimensionally hydrogen-bonded molecular layers. Among these hydrophilic layers, the methylbenzene moieties cluster together to form hydrophobic layers.

• Membrane Journal
• /
• v.19 no.1
• /
• pp.25-33
• /
• 2009

PES (polyethersulfone) membranes with highly enhanced their asymmetry were prepared by phase inversion process. The membranes were prepared by using PES/DMF (N,N-dimethylformamide)/TSA (p-toluenesulfonic acid)/PVP (polyvinylpyrrolidone) casting solution and water coagulant. The pre-coagulation of membrane surface which was induced by an addition of TSA as a demixing agent and PVP as a swelling polymer in the PES solution and humid exposure time, played a crucial role in determining morphological properties and the PWP (pure water permeation) performance. The PES solution was coated on polyester film under condition of 80% humidity for a while ($72{\sim}144$ sec) before immersing in a coagulation bath. The characterization of membranes was carried out by a capillary flow porometer, a FE-SEM and a permeation test apparatus. As the thickness of the smallest pore size layer (SPL) decreased, the asymmetry of membrane increased under conditions of 20 wt% of TSA and 10 wt% of PVP in 11 wt% of PES solution during longer humid contact time. As a result, the membranes showed a remarkable increase of PWP.

• Membrane Journal
• /
• v.30 no.4
• /
• pp.252-259
• /
• 2020

Olefins are industrially important materials used for the synthesis of various petrochemicals. During the polymerization process, unreacted olefin monomers are discharged together with a large amount of nitrogen. For economic benefits, these olefin gases should be efficiently separated from nitrogen. In this study, a poly(glycidyl methacrylate-co-methyl methacrylate) (PGM) comb-like copolymer was synthesized and 4,4'-diaminoazobenzene (DAAB) was introduced to the copolymer to prepare a cross-linked membrane for C₃H₆/N₂ separation. PGM and DAAB were readily reacted at room temperature through an epoxide-amine reaction without additional thermal treatment. PGM-based membrane, which is a glassy polymer, showed a faster permeation of N₂ compared to C₃H₆. The pristine PGM membrane exhibited the N₂ permeability of 0.12 barrer and the high N₂/C₃H₆ selectivity of 32.4. As DAAB was introduced as a cross-linker, the thermal stability of the membrane was significantly improved, which was confirmed by TGA result. The N₂/C₃H₆ selectivity was decreased at 1 wt% of DAAB content, but the N₂ permeability increased by approximately 4.7 times. We analyzed N₂/C₃H₆ gas separation properties through a glassy polymer-based membrane, which has not been widely studied. Also, we proposed that thermal stability of the membrane can be greatly improved by the cross-linking method.