• Restorative Dentistry and Endodontics
• /
• 제21권2호
• /
• pp.505-516
• /
• 1996

The effects of application of dentin desensitizer containing glutaraldehyde (Gluma Desensitizer) and dentin adhesive system (All Bond 2) to the exposed dentin on the intradental nerve activity (INA) and the occluding aspects of dentinal tubules were investigated in cat canine teeth. Single pulp nerve units were dissected from the inferior alveolar nerve and indentified as $A{\delta}$-fiber units. The INAs elicited by 4M NaCl before and after the application of each experimental agent were compared. The morphological changes of exposed dentin surfaces and dentinal tubules in the dentin specimens used to record INAs were observed by SEM. The results obtained were as follows. 1. Eight $A{\delta}$-fiber units (conduction velocity: $8.0{\pm}4.0m$/sec) were identified. 4M NaCl evoked an irregular burst of action potentials which ceased immediately after washing. 2. In 4 $A{\delta}$-fiber units, the change of INA after the application of Gluma Desensitizer was $133.9{\pm}80.7%$ when it was compared with the INA before the application of the same agent. 3. In 4 $A{\delta}$-fiber units, application of All Bond 2 completely abolished the INA induced by 4M NaCl. 4. In specimens applied with Gluma Desensitizer, the formation of hybrid layer as well as the identification of resin penetration and reaction products with proteins in dentinal tubules were not clearly observed in interface between dentin and adhesive resin. In specimens applied with All Bond 2, the gap width of 2-$3{\mu}m$ was formed between exposed dentin and adhesive resin, and the hybrid layer and resin tags were not clearly formed either.

• 대한본초학회지
• /
• 제20권4호
• /
• pp.33-39
• /
• 2005

Objectives : Because Ligusticum sinense Root as well as those of Angelica tenuissima Root are sole as Gobon(藁本) in domestic markets, morphological characteristics of them are attempted to be distinguished. Methods : The slice of the tested material made by paraffin section technique was colored with Safranine Malachite Green contrast methods, and then observed and photographed by olymphus-BHT. Results : 1. Angelica tenuissima Root has considerable number of thick roots, but Chinese Ligusticum sinense Root and Ligusticum jeholense Root are composed of rhizomes mostly with small roots. 2. Intersection of rhizomes of Angelica tenuissima Root shows a 'V'-like arrangement of xylem vessel. 3. Chinese Ligusticum sinense Root and Ligusticum jeholense Root did not show the 'V'-like arrangement, and sliced fiber bundles were found in xylem. 4. There was no difference between Chinese Ligusticum sinense Root and Ligusticum jeholense Root. Conclusions : In conclusion, Angelica tenuissima Root, Chinese Ligusticum sinense Root, and Ligusticum jeholense Root show characteristic differences in internal forms, so that it is possible to distinguish them with optical microscope.

• 한국의류학회지
• /
• 제37권6호
• /
• pp.827-836
• /
• 2013

Indigotin, indirubin, berberine, palmatine, alizarin, and purpurin are major pigments of indigo plant, Phellodendron bark, and madder. The six pigments were examined using the HPLC-DAD-MS instrument for the purpose of the simultaneous detection of the pigments in a single sample run. The HPLC-DAD-MS method examined the individual pigment solutions in DMSO, a solution containing 6 pigments, and the DMSO extract of the silk dyed with a dye solution of 5 pigments excluding indirubin. The retention times of the HPLC chromatograms, ${\lambda}_{max}$ of the uv-vis absorption bands in the DAD analyses, and the molecular ions detected for the compound peaks in the MSD analyses were consistent throughout the analyses of individual pigment solutions, mixed pigment solutions, and dye extracted from silk dyeing. The developed instrumental method of the simultaneous detection of six pigments can identify dye in an exhumed textile if the textile is dyed using any one (or multiple) pigments of indigo, Phellodendron bark, or madder plant.

• 한국광학회지
• /
• 제14권4호
• /
• pp.351-354
• /
• 2003

본 논문에서는 0.8bit/s/Hz의 높은 대역효율을 얻을 수 있는 12.5GHz채널 간격의 양방향 초고밀도 파장분할다중화(UD-WDM: ultra-dense wavelength division multiplexing) 광채널을 80 km의 단일 모드 광섬유로 전송하였다. 초고밀도 WDM 시스템에서 요구되는 광채널 주파수의 안정화를 위해 BFL(beat-frequency-locking) 기술을 이용하였으며, 실험을 통하여 $\pm$200MHz 이내로 광채널을 안정화 시킬 수 있음을 보였다. 특히, 다수개의 비트 주파수 변별과 높은 주파수 변별력을 확보하기 위하여 RF 스펙트럼 분석기를 이용하였다. BFL 기술이 적용된 채널간격 12.5 GHz 양방향 광채널의 전송 패널티는 단방향 전송과 비교시 단지 0.3dB이었다.

• 대한본초학회지
• /
• 제20권4호
• /
• pp.77-82
• /
• 2005

Objectives : In order to distinguish Akebiae Caulis and Aristoiochiae Manshuriensis Caulis, their external and internal states were examined by microscope. Methods : The slice of the tested material made by paraffin section technique was colored with Safranine Malachite Green contrast methods, and then observed and photographed by olymphus-BHT. Results : 1. Akebiae Caulis has stone cells and fiber bundles in its pericycle part, which include square crystal of calcium oxalate. Outside of neogenesis has a lot of cells with square crystal of calcium oxalate. 2. Aristoiochiae Manshuriensis Caulis has a little lignified fiber bundles in its pericycle part, and parenchymatous cell has delicate starch grains and druse of calcium oxalate. Conclusions : In conclusion, internal forms of Akebiae Caulis and of Aristoiochiae Manshuriensis Caulis are different in that each includes square crystal of calcium oxalate and druse of calcium oxalate respectively, so that it may be possible to distinguish them with optical microscope.

• 한국기계가공학회지
• /
• 제15권3호
• /
• pp.36-43
• /
• 2016

Carbon fiber-reinforced silicon carbide (Cf-SiC) and SiC / SiC composites have high thermal conductivity, and excellent corrosion and wear resistance, a low coefficient for thermal expansion and are lightweight. This is why they are commonly used in parts of the aerospace industry to develop an aircraft thrust deflector, jet vane, combustion chamber, elevens, body flap, and a shingle. So, understanding how this state-of-the-art Cf-SiC affects both internal and external crack detection and determining issues during the manufacturing process of composite materials, should be evaluated according to valuation techniques in the external environment. In this paper, we apply a non-contact air ultrasonic technique of non-destructive testing techniques to perform a study on internal defect detection identification and assessment of carbon-fiber reinforced silicon carbide composites to perform basic research and applied research.

• Fibers and Polymers
• /
• 제5권3호
• /
• pp.198-203
• /
• 2004

Composite films were prepared by casting the solution of polyacrylonitrile (PAN) and single wall nanotube (SWNT) in DMF subsequent to sonication. The SWNTs in the films are well dispersed as ropes with 20-30 nm thickness. Moreover, AFM surface image of the composite film displays an interwoven fibrous structure of nanotubes which may give rise to conductive passways and lead to high conductivity. The polarized Raman spectroscopy is an ideal characterization technique for identification and the orientation study of SWNT. The well-defined G-peak intensity at 1580 $cm^{-1}$shows a dependency on the draw ratio under cross-Nicol. The degree of nanotube orientation in the drawn film was measurable from the sine curve obtained by rotating the drawn film on the plane of cross-Nicol of polarized Raman microscope. The threshold loading of SWNT for electrical conductivity in PAN is found to be lower than 1 wt% in the composite film. The electrical conductivity of the SWNT/PAN composite film decreased with increasing of draw ratio due to the collapse of the interwoven fibrous network of the nanotubes with uniaxial orientation.

• Smart Structures and Systems
• /
• 제4권4호
• /
• pp.391-406
• /
• 2008

This study attempts to develop a real-time debonding monitoring system for carbon fiber-reinforced polymer (CFRP) strengthened structures by continuously inspecting the bonding condition between the CFRP layer and the host structure. The uniqueness of this study is in developing a new concept and theoretical framework of nondestructive testing (NDT), in which debonding is detected without relying on previously-obtained baseline data. The proposed reference-free damage diagnosis is achieved based on the concept of time reversal acoustics (TRA). In TRA, an input signal at an excitation point can be reconstructed if the response signal measured at another point is reemitted to the original excitation point after being reversed in the time domain. Examining the deviation of the reconstructed signal from the known initial input signal allows instantaneous identification of damage without requiring a baseline signal representing the undamaged state for comparison. The concept of TRA has been extended to guided wave propagations within the CFRP-strengthened reinforced concrete (RC) beams to improve the detectibility of local debonding. Monotonic and fatigue load tests of large-scale CFRP-strengthened RC beams are conducted to demonstrate the potential of the proposed reference-free debonding monitoring system. Comparisons with an electro-mechanical impedance method and an inferred imaging technique are provided as well.

• Composites Research
• /
• 제28권5호
• /
• pp.277-284
• /
• 2015

본 연구의 목적은 고유진동 응답데이터로부터 적층된 GFRP 판구조의 섬유 물성 변화를 추정하는 것이다. 고등유한요소 상용프로그램(ABAQUS)와 연동된 알고리즘은 미시역학적 관점에서 손상된 요소를 추정할 뿐만 아니라 위치, 개수 및 정도를 탐색할 수 있다. 연동된 기법을 적용하여 역문제를 해결하기 위하여 본 연구에서는 모드형상 대신 제한된 몇 개의 고유진동수 데이터만을 적용하였다. 몇가지 수치해석 결과로부터 제안된 시스템 기법은 다양한 적층배열을 갖는 복합재료 적층판과 같은 복잡한 구조물의 섬유 강성 변화를 추정하는 데 수치해석적으로 효율적임을 보여준다.

• Journal of Biosystems Engineering
• /
• 제39권2호
• /
• pp.115-121
• /
• 2014

Background: Frequent outbreaks of foodborne illness have been increased awareness of food safety. CDC estimates that each year roughly 48 million people gets sick, 128,000 are hospitalized and 3,000 die of foodborne diseases in US. In Korea, 6,058 were hospitalized and 266 incidents were reported in 2012. It is required to develop rapid methods to identify hazard substances in food products for protecting and maintaining safety of the public health. However, conventional methods for pathogens detection and identification involve prolonged multiple enrichment steps. Purpose: This review aims to provide information on biosensors to detect pathogens in food products to enhance food safety. Results: Foodborne outbreaks continue to occur and outbreaks from various food sources have increased the need for simple, rapid, and sensitive methods to detect foodborne pathogens. Conventional methods for foodborne pathogens detection require tremendous amount of labor and time. Biosensors have drawn attentions in recent years because of their ability to detect analytes sensitively and rapidly. Principles along with their advantages and disadvantages of a variety of food safety biosensors including fiber optic biosensor, impedimetric biosensor, surface Plasmon resonance biosensor, and nano biosensor were explained. Also, future trends for the food safety biosensors were discussed.