• Journal of Sensor Science and Technology
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• v.21 no.5
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• pp.367-373
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• 2012

We fabricated a fiber-optic alpha/beta detector, which is composed of a sensing probe, a plastic optical fiber, a photomultiplier tube, and a multichannel analyzer, to obtain the energy spectra of radioactive isotopes. As inorganic scintillators of a sensing probe, a ZnS(Ag) film was coupled with a $CaF_2$(Eu) crystal for alpha and beta spectroscopy. In this study, $^{210}Po$ and $^{90}Sr$ were used as alpha and beta sources, respectively, and we measured the radiation energy spectra using a fiber-optic alpha/beta detector to identify alpha and beta emitting radionuclides for nuclear medicine application. Also, the variations of energy spectrum were obtained according to the length of plastic optical fiber.

• Analytical Science and Technology
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• v.23 no.2
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• pp.165-171
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• 2010

Glucose oxidase ($GOD_{ox}$) immobilized biosensor was fabricated by two methods. In one of the methods, gold nanoparticles (Au-NPs) prepared by ${\gamma}$-irradiation were loaded into the poly(maleic anhydride)-grafted multi-walled carbon nanotube, PMAn-g-MWCNT electrode via physical entrapment. In the other method, the Au-NPs were prepared by electrochemical reduction of Au ions on the surface of PMAn-g-MWCNT electrode and then GODox was immobilized into the Au-NPs. The $GOD_{ox}$ immobilized biosensors were tested for electrocatalytic activities to sense glucose. The sensing range of the biosensor based on the Au-NPs physically modified PMAn-g-MWCNT electrode was from $30\;{\mu}M$ to $100\;{\mu}M$ for the glucose concentration, and the detection limit was $15\;{\mu}M$. Interferences of ascorbic acid and uric acid were below 7.6%. The physically Au deposited PMAn-g-MWCNT paste electrodes appear to be good sensor in detecting glucose.

• Korean Journal of Materials Research
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• v.8 no.2
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• pp.173-178
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• 1998

$MgB_4O_7$: Tb, Tm, Dy, La, Ho and Nd phosphors have been prepared by sintering around $580^{\circ}C$ for 2 hours followed by flowing Ar gas. Activation energy and kinetic order of main peak of glow curve were studied by two methods peak shape method and initial rise method. By these methods, the estimated activation energies were $0.76\pm0.02eV$(Tb doped), $0.94\pm0.03eV$(Tm doped), $0.72\pm0.02eV$(Dy doped), respectively. The TL phosphors prepared in this work may be utilized to radiation sensor elements becaue of their high sensitivity to low energy X-ray.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.6
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• pp.1219-1226
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• 2017

In this paper, it is performed the optimal design of the UV LED bar which can be used variously. The UV LED Bar emits ultraviolet rays, so it is important to emit ultraviolet rays constantly for the purpose of use. In order to emit a certain amount of ultraviolet rays as ever, the ultraviolet ray emission should be driven by a constant current source within the operable input voltage range. And also the heat dissipation is particularly important because of the long ultraviolet emission retention time due to the UV utilization characteristics. In addition, since human body protection is essential, the algorithm is configured to operate according to human body detection using distance sensor and Bluetooth. Three 365nm UV LEDs were used in series to emit ultraviolet UVA, operating at the constant current of 500mA with an efficiency of 87.5% and a power consumption of 6.006W. The ultraviolet radiation dose was measured at $5.35mW/cm^2$ at the distance of 10 cm when measured by the Lutron ultraviolet measuring instruments.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.1100-1102
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• 2015

In the study, stereo-based of gamma-ray sources detector for the space including the gamma-ray source to scan in a raster scan method, and obtains a visible light image and the gamma-ray image. We went to retrieve and visualize the distance to source and the direction of the 3-dimension information from Stereo gamma-ray detectors. Configuration of the detector consisted of gamma-ray detecting sensor for gamma-ray Sources, pan-tilt for the scanning of the raster for detecting sources, and CCD camera for visible-light image. Implement a stereo structure of the device to measure the spatial distribution of source, the gamma-ray Detector and CCD camera for the stereo image acquisition was as each configuration 2. The gamma-ray detector and a visible light camera to revision the distribution of detection source, After performing each of the cameras of the stereo correction and shows the distribution of the gamma-ray Sources through 중첩 visible light image and the gamma-ray image. After Rectification process of Left and right image, we were derived visualization results of the stereo image.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.12
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• pp.545-552
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• 2003

When a Si PIN diode is exposed to fast neutrons, it results in displacement damage to the Si lattice structure of the diode. Defects induced from structural dislocation become effective recombination centers for carriers which pass through the base of a PIN diode. Hence, increasing the resistivity of the diode decreases the current for the applied forward voltage. This paper involves the development of a neutron sensor based on the phenomena of the displacement effect damaged by neutron exposure. The neutron effect on the semiconductor was analyzed. Several PIN diode arrays with various thickness and cross-section area of the intrinsic layer(I layer) were fabricated. Under irradiation tests with a neutron beam, the manufactured diodes have a good linearity to neutron dose and show that the increase of thickness of I layer and the decrease of cross-section of PIN diodes improve the sensitivity. Newly developed PIN diodes with thicker I layer and various cross section, were retested and then showed the best neutron sensitivity at the condition that the I layer thickness was similar to a side length. On the basis of two test results, final discrete PIN diodes with a rectangular shape were manufactured and the characteristics as neutron detectors were analyzed through the neutron beam test using on-line electronic dosimetry system. Developed PIN diode shows a good linearity as dosimetry in the range of 0 to 1,000cGy(Tissue) and its neutron sensitivity is 13mV/cGy at constant current of 5mA, that is three times higher than that of commercially available neutron detectors. And the device shows little dependency on the orientation of the neutron beam and a considerable stability in annealing test for a long period.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.6
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• pp.89-99
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• 2008

In this paper proposes a novel tacking algorithm regarding the power loss when operating a tracking system for a rapidly changing insolation to improve the power of PV hacking system. The tracking system of sensor method used in a conventional PV power station is unable to exactly track a sun position when lacking in the intensity of radiation and has the problem is malfunction of tracking system by a rapidly changing climatic. The tracking system of program method spends too much energy on the unnecessary operation of tracking system because that is unable to adapt itself to a outside factor of climatic environment. In case of tracking an azimuth and altitude of the sun in realtime, therefore, the actual PV power is less increasing than the power of tracking system fixed a specific position. To reduce the power loss, this pap proposes a novel control algorithm of the tracking system. Also, this paper is analyzed efficiency of traditional solar tracking method and proposed method, prove validity of proposed algorithm through demonstrable study.

• Journal of Sensor Science and Technology
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• v.30 no.5
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• pp.320-325
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• 2021

Biochemical oxygen demand (BOD) and chemical oxygen demand (COD) methods are conventional analytical methods to analyze water quality. Both of these methods are technically indirect measurement methods, require complicated preconditions, and are time-consuming. On the other hand, the total organic carbon (TOC) method is a direct and fast measurement method which is more intuitive and accurate than the BOD and COD methods. However, general TOC analysis methods involve complicated processes and high power consumption owing to the process of phase transition from liquid to gas by a high-temperature heater. Furthermore, periodic consumables are also required for the removal of inorganic carbon (IC). Titanium dioxide (TiO₂) is one of the most suitable photocatalysts for simple processes. Its usage involves low power consumption because it only reacts with the organic carbon (OC) without the requirement of any other reagents and extra processes. We investigated a TiO₂ photocatalyst-based TOC analysis for simple and affordable products. TiO₂-coated fiber substrate maintained under carbon included water was exposed to ultraviolet (UV) radiation of wavelength 365 nm. This method is suitable for the real-time monitoring of water pollution because of its fast reaction time. Its linear property is also sufficient to match the real value.

• The Journal of Korean Medicine
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• v.42 no.1
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• pp.75-98
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• 2021

Objectives: The purpose of this study is to investigate the characteristics, validity, and reliability of non-radiological assessment tools of scoliosis that have been studied so far. Methods: Electronic databases including Pubmed, Cochrane Library, CNKI, Science On, RISS, OASIS were searched by keywords including 'scoliosis assessment', 'scoliosis screening', 'physical examination', 'functional measurement', 'photography', and 'smartphone'. Results: 32 articles using radiation-free assessments were identified from 1,011 records. The mostly used non-radiological methods were Surface topography, Scoliometer, Ultrasound, Digital Infrared Thermal Imaging, and Photography. The other methods were Gait analysis, 3D depth sensor imaging, and Low intensity electromagnetic scan. Conclusions: It was found that non-radiological assessment tools might reduce the number of radiographs taken in scoliosis patients. To increase the reliability and validity, further research on the measurement tools of scoliosis will be needed.

• Journal of radiological science and technology
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• v.43 no.6
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• pp.481-487
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• 2020

Radiation measurement technology has steadily improved and its usage is expanding in various industries such as nuclear medicine, security search, satellite, nondestructive testing, environmental industries and the domain of nuclear power plants (NPPs). Especially, the simultaneous measurements of gamma rays and neutrons can be even more critical for nuclear safety management of spent nuclear fuel and monitoring of the nuclear material. A semiconductor detector comprising cadmium, zinc, and tellurium (CZT) enables to detect gamma-rays due to the significant atomic weight of the elements via immediate neutron and gamma-ray detection. Semiconductor sensors might be used for nuclear safety management by monitoring nuclear materials and spent nuclear fuel with high spatial resolution as well as providing real-time measurements. We aim to introduce a portable nuclide-analysis device that enables the simultaneous measurements of neutrons and gamma rays using a CZT sensor. The detector has a high density and wide energy band gap, and thus exhibits highly sensitive physical characteristics and characteristics are required for performing neutron and gamma-ray detection. Portable nuclide-analysis device is used on NPP-decommissioning sites or the purpose of nuclear nonproliferation, it will rapidly detect the nuclear material and provide radioactive-material information. Eventually, portable nuclide-analysis device can reduce measurement time and economic costs by providing a basis for rational decision making.