• Polymer Science and Technology
• /
• v.7 no.2
• /
• pp.179-192
• /
• 1996

• Journal of the Optical Society of Korea
• /
• v.14 no.3
• /
• pp.235-239
• /
• 2010

In this study, we have fabricated two types of non-invasive fiber-optic respiration sensors that can measure respiratory signals during magnetic resonance (MR) image acquisition. One is a nasal-cavity attached sensor that can measure the temperature variation of air-flow using a thermochromic pigment. The other is an abdomen attached sensor that can measure the abdominal circumference change using a sensing part composed of polymethyl-methacrylate (PMMA) tubes, a mirror and a spring. We have measured modulated light guided to detectors in the MRI control room via optical fibers due to the respiratory movements of the patient in the MR room, and the respiratory signals of the fiber-optic respiration sensors are compared with those of the BIOPAC$^{(R)}$ system. We have verified that respiratory signals can be obtained without deteriorating the MR image. It is anticipated that the proposed fiber-optic respiration sensors would be highly suitable for respiratory monitoring during surgical procedures performed inside an MRI system.

• Journal of Sensor Science and Technology
• /
• v.23 no.4
• /
• pp.245-250
• /
• 2014

When the charged particle travels in transparent medium with a velocity greater than that of light in the same medium, the electromagnetic field close to the particle polarizes the medium along its path, and then the electrons in the atoms follow the waveform of the pulse which is called as Cerenkov light or radiation. This type of radiation can be easily observed in a spent fuel storage pit. In optical fibers, the Cerenkov light also can be generated due to their dielectric components. Accordingly, the radiation-induced light signals can be obtained using optical fibers without any scintillating material. In this study, to measure the intensities of Cerenkov radiation induced by gamma-rays, we have fabricated the fiber-optic Cerenkov radiation sensor system using silica optical fibers, plastic optical fibers, multi-anode photomultiplier tubes, simulated spent fuel assembly and a scanning system. To characterize the Cerenkov radiation generated in optical fibers, the intensities of Cerenkov radiation generated in the silica and plastic optical fibers were measured. Also, we measured the longitudinal distribution of gamma rays emitted from the Ir-192 isotope by using the fiber-optic Cerenkov radiation sensor system and simulated spent fuel assembly.

• Science of Emotion and Sensibility
• /
• v.14 no.4
• /
• pp.495-502
• /
• 2011

The plastic optical fiber has been previously known to have the limits in fabrication and care, due to its lack of flexibility and durability. Recently, an innovative technology of 'water-resistant & flexible optical fiber', in which the surface of etched POF(i.e., plastic optical fiber) is to be coated with a type of synthetic resin, has been developed. In this study, the post-treated POF-based flexible textiles were evaluated in terms of luminance, physical visibility and perceived visibility, according to the fabric lengths and colors of the light source. The POF-based flexible textile with 10cm fabric length and green light source appeared to show relatively higher illuminating effects. The maximum distance for perceived visibility of the POF-based flexible textiles was found to be 100m. Therefore, the results of this study are expected to be utilized as a fundamental for the further studies to develop the digital color clothing with application of POF-based flexible textile.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2004.04a
• /
• pp.111-114
• /
• 2004

Using the embedded optical fiber sensor of totally-reflected extrinsic Fabry-Perot interferometer(TR-EFPI), longitudinal strains(Ex) of the core and skin layers in glass fiber reinforced plastic(GFRP) cross-ply composite laminates have been measured. Transmission optical microscopy was employed to study the damage formation around the TR-EFPI sensor. It was observed that values of ex in the interior of the skin layer and the core layer measured by embedded TR-EFPI sensor was significantly higher than that of the specimen surface measured by strain gauges. The experimental results agreed well with those from finite element analysis on the basis of uniform stress model. Large strains in the core layer led to the occurrence of transverse cracks which drastically reduced the strain at failure of optical fiber sensor embedded in the core layer.

• Proceedings of the Optical Society of Korea Conference
• /
• 2008.07a
• /
• pp.313-314
• /
• 2008

• Polymer Science and Technology
• /
• v.13 no.2
• /
• pp.168-179
• /
• 2002

• Journal of Sensor Science and Technology
• /
• v.18 no.5
• /
• pp.365-371
• /
• 2009

In this study, we have fabricated a fiber-optic pH sensor which is composed of a light source, plastic optical fibers and a spectrometer. As an indicator, a phenol red is used, and a pH liquid solution is prepared by mixing of phenol red and various kinds of pH buffer solutions in these experiments. The emitting light from a light source is guided by plastic optical fibers to the pH liquid solution, and the optical characteristic of a light is changed in the pH liquid solution according to its color change. Therefore, we have measured the intensities and wavelength shifts of the modulated lights, which are changed due to the color variations of phenol red at different pH values, by using of a spectrometer for spectral analysis. Also, the relationships between the pH values of liquid solutions and the optical properties of modulated light according to the change of color of phenol red are obtained.

• Journal of Sensor Science and Technology
• /
• v.17 no.2
• /
• pp.100-105
• /
• 2008

The objectives of this study are to measure and to remove Cerenkov lights generated in a fiber-optic radiation sensor by a charge-coupled device. we have fabricated a fiber-optic radiation sensor which comprises an organic scintillator, a plastic optical fiber and a charge-coupled device. Charge-coupled device as a light measuring tool has many advantages which are easy in multi-dimensional measurements, high spatial resolution and relatively low cost.

• Journal of Sensor Science and Technology
• /
• v.23 no.3
• /
• pp.173-177
• /
• 2014

A Rhodamine-based fiber-optic sensor has been developed to detect mercury ions in aqueous environments. The fiber-optic sensor was composed of a mercury-sensing thin film, plastic optical fibers, and a spectrometer. The mercury-sensing thin film with the synthesized Rhodamine derivatives was fabricated with Sol-Gel process. A light emitted by a light source is guided by plastic optical fibers into the thin film in an aqueous solution and a reflected light is analyzed with the spectrometer. The experiment exhibits that an absorbance in the thin film is increased as mercury concentration is increased in the solution and the absorbance by mercury is higher than that by other heavy metals. The fiber-optic sensor exhibits high chromogenic phenomenon of mercury ions among various heavy metals and the correlation between absorbance and mercury concentration in the aqueous environments.