• Bulletin of the Korean Chemical Society
• /
• v.17 no.3
• /
• pp.228-234
• /
• 1996

The rates of solvolysis of 1-(4-methoxyphenyl)-1-aryl-2,2,2-trifluoroethyl chlorides[I] in a variety of solvents were measured by an electroconductometric method. LArSR relationships (Yukawa-Tsuno eq.)were found to give a linear plot, log(k/ko)=-1.84[σo+0.918(σ+-σo)], in 80% aqueous ethanol. Small |ρ| and r values in comparison with 1-aryl-1-(trifluoromethyl)ethyl tosylate(ρ=-6.09, r=1.59) suggested that the carbocationic charge in the transition state was dispersed by a strong p-π donor, p-methoxy group. Linear mY plots with m 0.90 for all of the substituents in aqueous acetone and m=0.60-0.82 for those of aqueous ethanol indicate that this solvolysis proceeds via an SN1 mechanism with nucleophilic solvent assistance. Thiourea effects and isokinetic temperatures for the rate of solvolysis also can prove the above mechanism.

• Bulletin of the Korean Chemical Society
• /
• v.16 no.4
• /
• pp.305-309
• /
• 1995

The enantiomeric separation of several amino acid derivatives by reversed-phase liquid chromatography using two (R)-and (S)-naphthylethylcarbamate-β-cyclodextrin(NEC-β-CD) bonded stationary phases was studied to illustrate the chiral recognition model of the enantiomeric separation. The retention and enantioselectivity of the chiral separations with (R)-and (S)-NEC-β-CD bonded phases were compared with similar separations with the native β-CD stationary phases. Especially, the enantioselectivity and elution orders between the derivatized amino acid enantiomers are carefully examined. These results can be illustrated by the chiral recognition models involving inclusion complexation, π-π interaction, and/or hydrophobic interaction. Inclusion complexation and hydrophobic interaction of the naphthyl group of the NEC moiety seem to be major chiral recognition components in the enantiomeric separation of 2,4-dinitrophenyl amino acids and dabsyl amino acids on (R)-and (S)-NEC-β-CD columns. For dansyl amino acids, only the inclusion complexation is the dominant factor. Three different chiral recognition models containing π-π interaction, inclusion complexation and hydrogen bonding were proposed for the separation of the 3,5-dinitrobenzoyl amino acid enantiomers, depending on the size and shape of amino acids.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.5 no.1
• /
• pp.65-84
• /
• 1995

The information security is needed to guarantee the safety and the confidence to users in open system. This paper analyzes transport layer security protocol and security association protocol, which are standards proposed by ISO/IEC, to provide a security service in the transport layer and particulars, not in the standard, are defined for development. And this paper suggests a development model and develps security system based upon the suggested model. The ONP of USL is used as the development environment.

• Transactions of Materials Processing
• /
• v.30 no.1
• /
• pp.27-34
• /
• 2021

In this study, response surface method (RSM) was used in modeling and multi-objective optimization of the parameters of AA5052-H32 in incremental sheet forming (ISF). The goals of optimization were the maximum forming angle, minimum thickness reduction, and minimum surface roughness, with varying values in response to changes in production process parameters, such as tool diameter, tool spindle speed, step depth, and tool feed rate. A Box-Behnken experimental design (BBD) was used to develop an RSM model for modeling the variations in the forming angle, thickness reduction, and surface roughness in response to variations in process parameters. Subsequently, the RSM model was used as the fitness function for multi-objective optimization of the ISF process based on experimental design. The results showed that RSM can be effectively used to control the forming angle, thickness reduction, and surface roughness.

• Textile Coloration and Finishing
• /
• v.32 no.4
• /
• pp.226-231
• /
• 2020

This study investigated effect of particle sizes of polymer binders for digital textile printing(DTP) pigment inks on touch of fabrics. The polymer binders were synthesized via miniemulsion polymerization of methyl methacrylate(MMA), butyl acrylate(BA), N-ethylolacrylamide(NEA) and methacrylic acid(MAA). The prepared binders were applied to black pigment inks and those black pigment inks were used to dye cotton fabrics. Then, color strength, rubbing fastness, stiffness, surface and bending properties of the dyed fabrics were investigated. Depending on the particle size of the polymer binder used, color strength, friction fastness, stiffness, surface and bending properties change. Generally, the larger the particle size of the polymer binder, the softer properties.

• Applied Chemistry for Engineering
• /
• v.32 no.3
• /
• pp.253-259
• /
• 2021

Colorectal cancer (CRC) is one of the most prevalent diseases in modern society, constituting a serious threat to global health. Currently, routine clinical screening and early removal of precancerous polyps are the most successful methods for reducing CRC incidence and mortality. However, the high cost and invasive detection of sigmoidoscopy and colonoscopy limited the CRC-screening participation and prevention. The emergence of biosensors provides an inexpensive, sensitive, less invasive tool for detecting CRC disease biomarkers. This review highlights some of recent efforts made on developing biosensors with electrochemical and optical techniques targeting CRC specific protein biomarkers for early diagnosis and prognosis, potential applications, and future perspectives.

• Human Ecology Research
• /
• v.60 no.1
• /
• pp.39-52
• /
• 2022

The purpose of this study was to investigate whether attachment to primary caregivers and family interaction affect rural children's social competence through self-regulation ability. To achieve this, a survey was conducted with 345 students aged 11-13 attending elementary schools in a rural area of Gyeongsang Province. Data were analyzed using descriptive statistics, Pearson correlation analysis, and path analysis using the AMOS 23.0 program. The main result was that rural children's self-regulation had an indirect effect on attachment with primary caregivers and family interaction through social competence. The findings of this study will contribute to designing a variety of programs that can promote the positive development of social competence among rural children.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2010.11a
• /
• pp.629-632
• /
• 2010

본 논문에서는 Fringe Pattern profilometry(FPP)을 이용한 높이 측정 시스템을 구현하고, R, G, B 각 컬러 채널별로 위상이 다른 파형을 인가함으로써 Phase shifting 방법을 이용한 실시간 위상 정보를 획득할 수 있게 한다. 디지털 프로젝터의 비선형성으로 인해 필연적으로 발생하는 하모닉스 성분을 근사화된 정현파를 인가함으로써 높이 정보에서 가장 큰 문제를 발생하는 2차 하모닉스 성분을 줄인다. 이렇게 구한 위상 값을 Digital Phase Loop Lock(DPLL)회로에 인가함으로써 3차원 모양 정보를 실시간으로 획득 가능하게 한다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2010.11a
• /
• pp.712-715
• /
• 2010

본 논문은 한 장의 이미지로 카메라와 물체 사이의 거리를 실시간으로 구하는 방법을 제안한다. 일정한 거리 차이를 가지는 이중 평면 거울을 물체와 카메라 사이에 45도 각도로 위치 시킨 후 이미지를 얻게 되면 동일한 물체에 대해서 일정한 거리 차이가 나는 두 장의 이미지를 얻게 되는 효과를 가진다. 이 정보의 차이를 삼각측량법에 적용시키면 거울과 물체 사이의 거리를 측정할 수 있게 된다. 한장의 이미지로 거리를 측정 할 수 있기 때문에 이를 실시간 처리가 가능한 하드웨어로 구현 하였다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2010.11a
• /
• pp.542-545
• /
• 2010

모바일은 사용자의 여섯 번째 감각의 도구로써 신체의 일부가 되고 있으며 사용자의 감정이나 행동패턴 등의 상황 정보를 분석하여 사용자의 의도나 요구사항을 예측할 수가 있다. 본 논문에서는 안드로이드를 기반으로 사용자의 감정을 포함한 다양한 상황을 인지하고 감정과 상황에 따른 사용자의 행동을 추론할 수 있는 상황인지 스마트 폰을 제안한다. 상황인지 스마트폰은 카메라에서 입력된 사용자의 얼굴 영상을 통해 감정을 인지하고 감정에 따른 행동과 그 때의 상황정보를 조합하여 히스토리 DB에 축적된다. 또한 현재의 감정과 상황 정보에 따라 과거의 히스토리DB를 비교 분석하고 현재의 행동을 추론한다. 이것은 사용자에게 고차원적인 서비스를 제공해줄 수 있다. 상황인지 스마트폰은 감정을 인지하는 감정인지 매니저와 상황 정보를 수집하고 관리하는 컨텍스트 매니저, 행동을 추론하는 추론 매니저로 구성된다.