• 대한방사선기술학회지:방사선기술과학
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• 제41권6호
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• pp.603-610
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• 2018

This study examined the following: accuracy of the exposure conditions in the inverter device and three-phase device; output waveform over the exposure conditions; and average and standard deviation of the output waveform. After assessing whether the dose corresponding to the theoretical dose was presented, the following conclusions were obtained: 1. The accuracy of the tube voltage(kVp) and tube current(mA) exposure time(sec) was within the tolerable level prescribed in Korea's Safety Management Standards. In the error, Inverter device was large the tube voltage and exposure time, the three-phase device was large the tube current. 2. In terms of the output waveform of the exposure conditions and the average and standard deviation of the output waveform, the higher tube voltage and larger tube current resulted in greater standard deviation in pulsation. Moreover, the standard deviation of pulsation was shown to be greater in the inverter device than the three-phase device; there was also greater standard deviation in the inverter device considering the exposure time. 3. Regarding the exposure conditions over the output dose, all linearity showed the coefficient of variation which had an allowable limit of error within 0.05. Although the output dose ratio for the inverter device was 1.00~1.10 times no difference that of the three-phase device, there was almost no difference in dose ratio between the tube currents.

• 대한방사선기술학회지:방사선기술과학
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• 제27권4호
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• pp.37-41
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• 2004

목 적 : 측정을 통한 장치의 성능관리 평가로 임상실무에서의 능력배양과 정확한 관전압, 조사시간, 출력선량을 측정하는 기술을 익히고 병원에서 사용 중인 간접촬영용 X-선 발생장치 성능현황을 파악하기 위함이다. 재료 및 방법 : 관전압, 조사시간, 출력선량 측정기를 이용하여 10개 대학병원 간접촬영용 X-선 발생장치(원내,외 각 10대)를 이용하였다. 결 과 : 관전압 정확도 시험 PAE 판정에 의해 부적합한 간접촬영기는 3대가 나왔으며, 조사시간의 정확도 시험에서는 2대, 또한 조사선량의 재현성 시험에서도 조사선량에 대한 변동계수를 계산한 결과 3대가 나왔다. 3가지 성능검사에서 원외(이동차량)의 부적합한 간접촬영기는 5대, 원내는 3대로 원외(이동차량)의 간접촬영기가 원내보다 부적합한 것이 높게 나타났다. 결 론 : 간접촬영기의 성능을 일정하게 유지함으로서 방사선 피폭경감, 화질관리, 재촬영 감소 등에 의해 환자에게 양질의 의료서비스를 제공할 수 있는 여건을 마련할 수 있을 것이다. 따라서 정기적인 성능검사가 필요하다고 사료된다.

• 한국환경보건학회지
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• 제30권5호
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• pp.481-486
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• 2004

Vehicle occupant exposure to air pollutants has been a subject of concern in recent years because of higher levels of air pollutants inside gasoline or diesel-using vehicle, comparing to the surrounding atmosphere. Contrary to previous studies, fuel of vehicles operated in this study was liquefied petroleum gas (LPG). This study examined the potential exposure and removal efficiency of selected volatile organic compounds (VOCs), nitrogen dioxide ($NO_2$) and respirable suspended particle (RSP) by commercial air cleaning device inside vehicle under different ventilation conditions. Vehicle concentrations inside of benzene, toluene, m,p-xylene, $NO_2$ and RSP were lower under the low ventilation condition. This was indicated that outdoor air pollutants could affect the vehicle air quality inside in case metropolitan cities such as Daegu. The urban vehicle concentrations inside of benzene, toluene, m,p-xylene, $NO_2$ and RSP with air cleaning device were higher than those without air cleaning device. This means that the use of air cleaning device equipped with activated carbon filter, which was used in this study, in the interior of vehicles could be expected to reduce the vehicle occupants exposure to air pollutants effectively. In batch type reactor of laboratory scale, removal efficiencies of air cleaning device used were $97.0\%,\;95.7\%,\;94.6\%\;and\;85.5\%$ respectively in benzene, toluene, m,p-xylene and $NO_2$.

• 대한방사선기술학회지:방사선기술과학
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• 제44권3호
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• pp.189-194
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• 2021

This study was conducted to reduce the exposure dose to the breast and adjacent organs as the number of Mammography increased. Therefore, it has been designed a shield in lead, bismuth + tungsten, and bismuth that does not require to be equipped by the patient, in which each type of shield was compared and analyzed of radiation exposure dose to breast, thyroid, and eye. Using a mammography machine, optically stimulated luminescent dosimeter(OSLD) was inserted to bilateral breast, thyroid, and eye of a dosimetry phantom to measure dose radiated onto the phantom. Shielding device was made in different thickness of 2mm, 3mm, and 5mm and dose evaluation was performed by measuring the dose while using lead, bismuth, and bismuth + tungsten prosthesis. When each shields combined with shielding device, were compared of dose, all showed similar does reduction in the dose to breast, thyroid, and eye in both cranialcaudal and mediolateraloblique view. Based on the current study, bismuth and bismuth + tungsten can replace conventional lead shield and it is anticipated to safely and conveniently reduce radiation exposure to breast, thyroid, and eye with the shield that does not require to be equipped.

• 센서학회지
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• 제27권6호
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• pp.368-373
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• 2018

The effects of long-term exposure of high and low humidity on thin-film humidity sensors are investigated. Five commercially available thin-film humidity sensors are initially calibrated in a humidity chamber as a reference before longterm exposure to high and low humidity. Then, the sensors are kept in a high-humidity environment (~95 %rh) for four months. After the exposure, the sensors are calibrated in the same manner as the initial calibration. Consequently, the device reading values from the humidity sensors are elevated up to about 5 %rh. Interestingly, the degree of elevation by the high-humidity exposure shows a negative correlation with the price of the humidity sensors. Humidity sensors are then kept in a low-humidity environment (~10 %rh) for another four months. After the exposure, a calibration similar to the initial calibration is performed. As a result, the device reading from humidity sensors is decreased, indicating a recovery from the effect of high-humidity exposure. The durability test conducted in this study provides experimental evidence for the use of thin-film humidity sensors in high-humidity environments such as greenhouses and food factories for a long period of time.

• 센서학회지
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• 제32권2호
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• pp.100-104
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• 2023

In this study, a device was fabricated to check the possibility of a memory device by controlling the oxygen functional groups in graphene oxide formed with a 45-second exposure time. We discovered that graphene oxide can be formed using the ultraviolet (UV) light treatment method with different exposure times. Moreover, Raman spectroscopy measurement revealed that the oxygen functional groups can be moved by controlling the voltage. We further studied the change in the local graphene oxide region, which was found to be related to the modulation of the electrical properties of the device. Therefore, the fabricated graphene oxide device can be used as a wettability switching membrane and graphene-based ion transport device.

• Nuclear Engineering and Technology
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• 제54권7호
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• pp.2606-2613
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• 2022

Spent resin often exceeds radiation limits for safe disposal, creating a need for commercial-scale treatment techniques to reduce resin radioactivity. In this study, the radiological safety of a commercialized spent resin treatment device with a treatment capacity of 1 ton/day was evaluated. The results confirm that the device is radiologically safe in the event of an accident. This device desorbs ¹⁴C from the spent resin, allowing disposal as low-level waste instead of intermediate-level waste. The device also reduces overall waste by recycling the extracted ¹⁴C. Potential accident scenarios were explored to enable dose assessments for both internal and external exposure while preventing further spillage of the device and processing the spilled resin. The scenarios involved the development of a surface fracture on the resin mixture separator and microwave systems, which were operated under pressure and temperature of 0-6 bar and 0-150 ℃, respectively. In the case of accidents with separator and microwave device, the maximum allowable working time of worker were derived, respectively, considering external and internal exposures. When wearing the respirator corresponding to APF 50, in the case of the microwave device accident scenario, the radiological safety was confirmed when the maximum worker worked within 132.1 h.

• 대한의생명과학회지
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• 제14권3호
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• pp.173-178
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• 2008

With the widespread use of laser in medical and industrial settings, the incidence of laser injury to the ocular continues to grow among workers involved in handling lasers. The aim of this study is to compare ocular damages after irradiation with various laser wavelengths and power density. Ocular of pigmented rats was irradiated with $CO_2$ laser, 1064 nm Nd:YAG laser, and 532 nm diode laser. We observed damage of cornea, lens, and retina using slit lamp microscope and funduscopy. H&E staining of histopathology were applied to study the specimens. The higher exposure ($200mW/cm^2$, 10 sec) with $CO_2$ laser resulted in severe damage at the cornea. For the 1064 nm Nd:YAG laser, the higher exposure than $10mW/cm^2$ (10 sec) resulted in damage at the cornea and lens. Further, with the 532 nm diode laser, retinal lesions were induced when $10mW/cm^2$ (0.25 sec) was delivered to the eye. Theses results suggest that the ocular damages are different from various laser wavelength and power density.

• 한국임상수의학회지
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• 제41권3호
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• pp.157-164
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• 2024

The standard radiation protection method in the angiography suite involves the use of a thyroid shield, a lead apron, and lead glasses. However, exposure to substantial amounts of ionizing radiation can cause cataracts, tumors, and skin erythema. A newly developed curtain-type radiation protection device consists of a curtain drape composed of a five-layer bismuth and lead acrylic head-shielding plate, with both bearing an equivalent 0.25 mm lead thickness. In this study, a quality assurance phantom was used as the patient to create radiation scatter from the radiographic source, and an anthropomorphic mannequin phantom was used as the interventionalist to measure the radiation dose at seven different anatomical locations. Thermoluminescent dosimeters were used to measure the radiation dose. The experimental groups consisted of all-sided or one-sided curtain set-ups, the presence or absence of a conventional shielding system, and the orientation of beam irradiation. Consequently, the curtain-type radiation protection device exhibited better radiation protection range and capabilities than conventional radiation protection systems, especially in safeguarding the forehead, eyes, arms, and feet, with minimal radiation exposure. Moreover, the mean shielding ratios of the conventional shielding system and curtain-type radiation protection device were measured at 51.94% and 93.86%, respectively. Additionally, no significant decrease in the radiation protection range or capability was observed, even with changes in the beam orientation or one-sided protection. Compared with a conventional shielding system, the curtain-type radiation protection device decreased radiation exposure doses and improved comfort. Therefore, it is a potential new radiation protection device for veterinary interventional procedures.

• 대한방사선기술학회지:방사선기술과학
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• 제31권2호
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• pp.123-127
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• 2008

목 적: 임상에서 인버터식 X선장치의 사용이 보편화됨에 따라 이에 대한 보다 정확하고 간편한 성능평가 방법이 요구되고 있다. 따라서 최근 국내에 소개되어 사용되고 있는 X-Ray Multi-Function Test Device (model : Xi (unfors)-prestige)를 이용한 성능평가의 유용성을 확인하고자 한다. 방 법: 인버터식 X선장치의 성능 평가시 접속형 측정장비로 널리 활용되고 있는 Dynalyzer III를 이용한 성능평가를 기준으로 하여 비접속형 측정장비인 X-Ray Multi-Function Test Device (model: Xi (unfors)-prestige)의 성능평가를 비교 분석하여 그 유용성을 검토하였다. 결 과: 두 측정기에 대한 X선 출력선량은 큰 차이 없이 측정되었으며 촬영조건 등의 변화에 따라서 접속형인 Dynalyzer III가 약간 증가된 값으로 측정되었으며 출력의 재현성은 두 측정기 모두 성능평가 합격 기준 0.05 이하인 0.002 이하로, 직선성은 합격기준인 0.1 이하로 평가되었다. 촬영조건의 정확도에서는 관전압은 1.8과 2, 관전류는 2.01과 2.3, 촬영시간은 T > 0.01 sec에서 ${\pm}10%$ 이하로 나타났다. 모두 성능평가 기준의 허용범위에 있는 것으로 나타났다. 결 론: X-Ray Multi-Function Test Device (model: Xi (unfors)-prestige) 측정기를 이용한 인버터식 X선장치의 X선 출력의 재현성, 직선성과 촬영조건의 정확도에 대한 성능평가의 유용성을 확인하였다.