Min Sang Lee

N-doped graphene-carbon nanotube hybrid networks attaching with gold nanoparticles for glucose non-enzymatic sensor

Herein, we successfully developed a novel three dimensional (3D) opened networks based on nitrogen doped graphene‑carbon nanotubes attaching with gold nanoparticles (N-GR-CNTs/AuNPs) to apply for non-enzymatic glucose determination. It was demonstrated that the N-GR-CNTs/AuNPs modified electrode exhibited good behavior for glucose detection with a long linear range of 2 μM to 19.6 mM, high sensitivity of 0.9824 μA·mM-1·cm-2, low detection limit of 500 nM, and negligible interference effect. The high performance of the N-GR-CNTs/AuNPs based sensor was assumed due to the outstanding catalytic activity of AuNPs well dispersing on N-GR-CNTs networks, which exhibited as a perfect supporting scaffold due to the enhanced electrical conductivity and large surface area. The obtained results indicated that the N-GR-CNTs/AuNPs hybrid is highly promising for sensitive and selective detection of glucose in sensor application.

The Analysis of Thermal Characteristics of Carbon Containing PET Surface Element According to the Area Density and Electrode Shape

The temperature uniformity of most carbon fiber is degraded on the entire area. Therefore, understanding the thermal characteristics based on surface density and electrode shape becomes necessary. In this paper, the samples were fabricated according to the area density of carbon fiber and polyethylene terephthalate (8.8 g/m2, 20.2 g/m2, 42.1 g/m2). Different voltages (2V, 4V, 6V) were applied on them and the image was taken using thermal camera. Initially, the samples were investigated for morphology and element characterization by SEM-EDAX of surface heating elements and found that increased area density resulted in increase in the number of carbon atoms and decrease in number of oxygen atoms. It was also found from sheet resistance test that area density has inverse proportional relation with sheet resistance. In addition to that, regardless of the shape of the electrode, the increase in area density leads to a rise in temperature. It also increased the range of the temperature variation. Therefore, the uniformity and temperature stability can be satisfied by securing the electrode part as wide as possible through uniform electrode shape. In case of homogeneous electrode type, the saturation time of maximum temperature was 270 seconds, and the loading time was longer than 70 seconds of the concentrated electrode type. Therefore, in order to satisfy the reference temperature (30°C~ 50°C), the required surface heating product should be manufactured with the area density of 20.2 g/m2 at a voltage applied around 6V or less.

A Study on the Analysis of Bending Strength of Carbon Composite Skin Using Wire Mesh

Composite materials with advantage of high strength, rigidity, corrosion resistance than a normal metal material are widely used in applications such aerospace, automotive, marine requiring safety and weight reduction by continuous research and development, especially large in electromagnetic shielding areas spotlighted. In conventional electromagnetic shielding areas, where metal materials are mainly used, polymers and composite materials are drawing attention as a substitute material for it. Composites mechanical properties are changed in accordance with the stacked alignment angle, the number of stacked layers and the layered material. By laminating the carbon fiber pre-preg and the Wire Mesh the test specimens were created. The bending tests were performed and by using an S-S Curve the bending strength and bending stiffness were analyzed.

A Study on the Nondestructive Evaluation of Carbon/Carbon Brake Disks Using Infrared Thermography

Carbon/carbon brake disks that use carbon fibers impregnated in a carbon matrix are widely utilized in aircrafts and automobiles owing to their high strength, high heat conductivity, low density, and excellent overall mechanical properties. Carbon/carbon brake disks are high cost products and require multi-process manufacturing. The safety and material efficiency of defective products reduces significantly and nondestructive testing is required to monitor the quality, homogeneity, and integrity of the material. In general, radiographic evaluations pose safety problems owing to the use of radiation in such evaluations and ultrasonic flaw detection is difficult to use because of its dependence on the surface of the specimen. This study uses an infrared thermography camera technique, which is not influenced by the sample surface, to monitor the heterogeneity of materials during the manufacturing process and to thus prove the reliability of the method.