• Korean Journal of Food Science and Technology
• /
• v.20 no.4
• /
• pp.553-557
• /
• 1988

To investigate the effect of storage humidity on the textural characteristics of crackers, their crispness and tenderness were measured by sensory and instrumental methods. Domestic cracker samples stored for 1 and 3 weeks at 4 different relative humidities of 23, 31, 51 and 79% showed the decrease in crispness intensity as the humidity increased while storage period did not affect their textural characteristics. When domestic and imported cracker samples were stored for 1 and 3 weeks at relative humidities of 31% and 79%, there was no significant difference in their textural characteristics.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2017.11a
• /
• pp.1068-1071
• /
• 2017

카 하이어링 서비스는 개개인간의 차를 공유할 수 있는 환경을 제공해주는 서비스 플랫폼이다. 카 하이어링 서비스에서는 일반적으로 웹 서버를 구축하여 자차의 대여를 원하는 개인이 해당 차량의 지역 정보, 등록 정보 등을 기입 저장한다. 이후 웹 서버를 통해 일련의 인증과정을 거친 사용자가 해당 지역에 등록되어 있는 차량의 이용을 원할 때, 서버로 본인의 유저 정보를 송신하여 차량을 대여할 수 있도록 서비스를 운영한다. 우리는 본 연구에서 비콘 기술과 영상처리를 통한 PSNR 검출을 사용하여 개인 간의 차량 대여에서 발생하는 보안성과 신뢰성 문제를 보완 향상시켜 카 하이어링 서비스를 활성화 할 수 있는 기반을 구축하고자 한다. 이를 위해 웹 서비스 구현, 인증된 사용자만이 차량을 이용할 수 있는 인증키 생성 및 암호화 알고리즘, 라즈베리파이를 비콘 스캐너로 활용한 인증키 검증 절차, 카메라 영상처리를 이용한 차량 동작 감지 방법의 구현으로 보안성을 강화한 시스템을 구축하였다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2016.04a
• /
• pp.1004-1007
• /
• 2016

점차 발전하는 자동차 산업에 맞추어 운전자들에게 보다 편리한 서비스를 제공하는 스마트 카에 대한 사회적 관심 또한 증가하고 있다. 이는 최근 스마트 카를 주제로 한 각종 어플리케이션이 등장하는 속도만 봐도 몸소 알 수 있다. 실제로 많은 운전자들이 차를 운전할 때 내비게이션의 목적지를 일일이 설정하는 것에 큰 번거로움을 느끼고 있으며, 이로 인한 사고의 위험성 역시 적지 않다. 이러한 기존의 문제점과 사회적 관심을 고려하여 사용자의 일상이 결합된 스마트 카 어플리케이션 '카스텔라'를 기획하였다. 매번 도로 위에서 목적지를 조작하는 과거의 자동차 내비게이션과 달리, '카스텔라'는 사용자가 등록한 일정을 내비게이션과 연동함으로써 사용자의 일상이 결합된 맞춤 서비스를 제공한다. 또한, 자신의 차량을 상대로 사용자를 등록하여 해당 사용자가 차량의 시동을 제어하는 시스템과 당일의 날씨에 따른 안전 멘트도 제공한다. 기존의 다른 어플리케이션과 달리 사용자 일정 차량이 하나로 녹아들어 사용자의 모바일과 자동차의 연동이 보다 편리하고, 사용자가 자신의 어플리케이션에 등록한 일정을 자동차의 내비게이션에서 바로 목적지로 설정할 수 있다는 것이 특징이다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2017.05a
• /
• pp.521-528
• /
• 2017

In this paper, the numerical analysis for heat conduction of silica/phenolic composite material, which is used for solid rocket nozzle liner or insulator, was conducted. 1-D Finite Difference Method for the analysis of silica/phenolic during the firing of solid rocket motor was used to calculate the heat conduction considering the surface ablation and the thermal decomposition. The boundary condition at the nozzle wall took into account the convective heat transfer, which was obtained by integration equation. The numerical results of the surface ablation and char depth were compared with the results of test motor that is TPEM-10. It was found that the result of calculation is favorably agreed with the thermal response of test motor.

• Journal of the Korean Ceramic Society
• /
• v.40 no.11
• /
• pp.1102-1105
• /
• 2003

The fiber drawing process induced defects in silica fiber have been investigated. This study has focused on the Oxygen Deficient Centers (ODCs) and E' centers induced by the fiberization process in low-OH silica fibers. To investigate those defects induced by the fiberization process, the optical absorption spectrum and Electron Spin Resonance (ESR) have both been employed. The concentration of Oxygen Deficient Centers (ODCs) and E' centers are increased by the fiber drawing process. The population of defects in the neck-down region has also been investigated. The most significant generation of defects during fiber drawing process has been shown to occur in this region of silica preform. The population of defects is higher on the edge region than in the center of neck-down region.

• Polymer(Korea)
• /
• v.28 no.5
• /
• pp.391-396
• /
• 2004

In order to overcome drawbacks in the conventional preparation of epoxy/silica nanocomposites, such as formation of micro voids and dimensional instability caused by evolution of volatile by-products during curing reaction, a novel preparation method using Si-N precursor has been proposed. When prepared through in-situ reaction of epoxy curing reaction with sol-gel reaction of Si-N precursor, methyltripiperidinylsilane (MTPS) which does not produce by-products during reaction, epoxy/silica nanocomposites of extremely even dispersion of inorganic phase could be successfully prepared, resulting in high enhancement of mechanical and thermal properties as well as outstanding transparency.

• Resources Recycling
• /
• v.21 no.2
• /
• pp.47-52
• /
• 2012

According to the diversification of types of concrete structures, the quality of the concrete which is demanded also, is becoming high performance essentially. The high performance of the concrete leads using of admixtures, generally, in order to produce high strength, concrete has been used to silica fume. Silica fume is excellent mechanical properties, but unlikely to be economic. So, recently as a replacement for silica fume, metakaolin is a lot of research underway. In this study, it is used the metakaolin substitute for silica fume. For in order to prevent loss of liquidity when occurs using the admixtures, we used the silica dioxide. Therefore, concrete with the admixtures and silicon dioxide were examined the mechanical properties.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.22 no.4
• /
• pp.76-84
• /
• 2018

In this paper, the numerical analysis for heat conduction of silica/phenolic composite material, used for solid rocket nozzle liners or insulators, is conducted. A 1-dimensional finite difference method for the analysis of silica/phenolic during the firing of a solid rocket motor is used to calculate heat conduction, considering surface ablation and thermal decomposition. The boundary condition at the nozzle wall, considering the convective heat transfer, is obtained via integration equations. The numerical results of the surface ablation and char depth are compared with the results of a TPEM-10 test motor, finding that the result of calculation agrees with the thermal response of the test motor.

• Journal of Adhesion and Interface
• /
• v.13 no.4
• /
• pp.151-155
• /
• 2012

In the present study, we synthesized mesoporous silica hollow spheres with different wall thickness using polystyrene (PS) spheres as a structure template, tetraethoxysilane (TEOS) as a silica source, cetyltrimethylammonium bromide (CTAB) as a template. Particle size and dispersion of PS spheres were strongly depended on the concentration of surfactant in the aqueous solutions. The size of PS spheres was increased with decreasing concentration of surfactants. Dispersion of PS particle was improved when the surfactant concentration was lower than 0.5 g of surfactant.

• Journal of Adhesion and Interface
• /
• v.15 no.1
• /
• pp.9-13
• /
• 2014

The purpose of this work is to investigate the specific gravity, thermal, and mechanical property changes of polypropylene (PP)/mica composites before and after solid-state extrusion. On increasing the filler content, the specific gravity of the composites increased. The specific gravity of the oriented specimen containing filler in PP matrix is found to be much smaller than that of pre-specimen due to the formation of more microvoids. The presence of microvoids in the case of oriented composite specimen significantly affected the tensile and flexural properties of the composites. Both flexural strength and modulus of the composites showed maxima when the mica contents was 10 wt%, regardless of the orientation via solid state extrusion.