• Journal of Magnetics
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• 제20권4호
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• pp.450-459
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• 2015

In this paper, the safety distances and maximum permissible power (MPP) of resonant wireless power transfer systems are defined and derived with regard to human exposure to electromagnetic field (EMF). The definition is based on the calculated induced current density and electric field in the standard human model located between the transmitting and receiving coil. In order to avoid the adverse health effects such as stimulation of nerve tissues, the induced current and electric field must not exceed the basic restriction values specified in EMF safety guidelines. The different combinations of diameters of the coils and the distance between the two coils are investigated and their effects are analyzed. Two versions of EMF safety guidelines (ICNIRP 1998 and ICNIRP 2010) are used as bases for safety distance calculation and the difference between the two guidelines are discussed.

• Nuclear Engineering and Technology
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• 제17권4호
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• pp.267-278
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• 1985

원자력발전소로부터 배출되는 방사성물질에 의한 피폭선량을 규제하는데 있어 몇 가지 종류들의 방식들이 적용되어 왔다. ICRP에 의해 권고된 일차 선량 당량 제한치가 가장 근본적인 것이다. 일차 제한치가 직접 적용될 수 없을 때 외부 피폭의 경우 선량당량 지표가 내부피폭의 경우 최대허용농도, 연섭취 제한치 흑은 유도대기 농도 및 최대 신체 부하량 등이 이용되어 왔다. 그러나 이 값들은 실제 배출량을 제어하는 견지에서 바로 사용할 수 없어 유도방출 기준치를 구하게 된다. 본 연구에선 월성 원자력발전소에 대해 고려되는 특정환경들 사이의 전달속도가 시간에 독립적인, 장기성 농축인자 방식으로 방출속도의 유도 제한치를 구하였다.

• 한국안전학회지
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• 제17권3호
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• pp.22-29
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• 2002

The safety device of infrared type for dangerous machine being used currently has a harmful effect on human's eye and skin. In this paper we explain about the characteristics of lasr source and analyze the amount of harmfulness on human's eye by simulation method. We used the datas given by ANSI in this simulation.

• 한국전자파학회논문지
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• 제7권4호
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• pp.353-362
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• 1996

본 논문에서는 토끼를 대상으로 하여 그 두부에 전자파가 조사(照射)된 경우에 대해 토끼 두부를 3충 구모델로 근사해서 SAR분포를 계산하였다. 계산 결과를 확인하기 위해 주파수 2,450MHz인 마이크로파를 출력세기별로 5그룹으로 설정하여 각각에 대한 노출 전 후의 EEG를 전두부(前頭部)에서 측정하였다. 실험에서 전자파 조사 후에는 뇌전위의 전체평균값은 조금 감소히였고, 특히 $\theta$, $\delta$그리고 $\beta$파의 평균합성비율은 증가하였다. 이 결과는 마이크로파 조사후 전기적 생리활동의 감소와 뇌파의 속파화 경향을 나타낸다. 측정된 뇌전위로써 생체에 대한 전기 생리적 효과를 정량적으로 파악하여 최대허용노출(Maximum Permissible Exm posure)의 객관적인 추정을 하였다.

• 한국환경과학회지
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• 제19권6호
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• pp.671-680
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• 2010

The present study evaluated residential exposure to atmospheric formaldehyde and acetaldehyde according to distance from the a dyeing industry complex (DIC). This purpose was achieved by measuring concurrently the outdoor air concentrations in residences near the DIC and a certain distance away, plus the outdoor air concentrations at two industrial areas within the DIC boundary. Formaldehyde concentrations (median values of 24.3 and $22.5{mu}g/m^3$ in IS1 and IS2, respectively) were higher than acetaldehyde concentrations (median values of 7.4 and $7.3{mu}g/m^3$ in IS1 and IS2, respectively) at both sites. However, there was no significant difference in the industrial outdoor air concentrations of both formaldehyde and acetaldehyde between the two sites. In addition, the median formaldehyde concentration from the residential site near the DIC (RS1) was about 1.5 times higher than that from the residential site far away from the DIC(RS2), and the median acetaldehyde concentration from RS1 was about 1.3 times higher than that from RS2. It is noteworthy that the mean or median risk as well as these maximum risks are well above the USEPA's permissible risk level of $10^{-6}$ from environmental exposure. This suggests that appropriate management for formaldehyde and acetaldehyde is necessary in order to decrease risk of the residents of study areas, regardless of the distance from the DIC.

• 한국광학회지
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• 제30권2호
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• pp.48-58
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• 2019

구면 초점 초음파 측정기에 의해 구형의 광 흡수체로부터 측정된 시간(즉, 펄스 형태 광원) 및 주파수 영역(즉, 처프 형태 광원) 광음향 신호의 신호 대 잡음비(signal-to-noise ratio)를 이론 및 시뮬레이션으로 분석하였다. 이전 문헌과 마찬가지로 시간 영역 광음향 측정에 의한 신호 대 잡음비 값이 주파수 영역 광음향 측정의 경우보다 더 높았는데 이 근본적인 이유를 최대허용노광량(maximum permissible exposure)에 따른 광원의 세기와 주파수 필터링을 통한 두 측정 모드의 광음향 스펙트럼들에 대한 분석을 통해 이해하였다. 또한, 분석의 결과로서 주파수 영역 광음향의 처프 형태 광원에 대한 정합 필터링에 더해 DC 스펙트럼 부분을 제거하니 신호 대 잡음비가 5 dB 정도 상승하는 것을 발견하였다. 특히, 주파수 필터 함수의 주파수 상한 값의 변화에 따라 신호대 잡음비 값이 급격하게 변동하였는데 신호 대 잡음비가 최대가 되는 주파수 상한 값이 두 광음향 측정 모드에서 서로 다르게 나타남을 관찰하였다.

• 한국산업보건학회지
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• 제18권1호
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• pp.32-40
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• 2008

Methyl bromide has been used as a representative fumigant for quarantine, and several poisoning cases have occurred recently by this chemical in Korea. The purpose of this study is to evaluate workers' exposures to airborne methyl bromide in the importing and exporting plant products quarantine companies. Air samples were collected 400/200 mg Anasorb 747TM and were analyzed by gas chromatograph /flame ionization detector according to the Occupational Safety and Health Agency (OSHA) Method PV2040. Geometric mean (GM) and arithmetic mean (AM) of total 27 workers' exposure concentrations to airborne methyl bromide were 1.12 ppm and 0.24 ppm, respectively. Two exposures(12.1 ppm and 12 ppm as 8hr-TWA) of total 27 workers' exposures exceeded the Korean standard (5 ppm) of Ministry Labor, while 4 exposures (15%) exceeded the Threshold Limit Value (TLV) (1 ppm) of American Conference of Governmental Industrial Hygienists (ACGIH). Seven samples (11%) of total 63 short-term air samples exceeded the OSHA Permissible Exposure Limit (PEL) 20 ppm (Ceiling). The opening (management) task in wood fumigation by tent showed the highest short-term exposure concentrations (AM: 18.6 ppm, GM: 0.58 ppm, maximum: 340.7 ppm). The maximum level in treatment task of the same process was 2.01 ppm. Methyl bromide concentrations in opening operation was significantly higher than that in treatment operation (p<0.05). In conclusion, the GM of workers' 8hr-TWA exposures to airborne methyl chloride in the importing/exporting plant quarantine industry was estimated below the ACGIH TLV (1 ppm). However, opening task in the fumigation of wood being covered with tent or fumigation of pant products in container showed the levels exceeding ACGIH TLV (1 ppm), and opening task in the fumigation of wood being covered with tent showed the level exceeding the Korean standard of Ministry of Labor (5 ppm).

• 한국대기환경학회지
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• 제9권3호
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• pp.191-199
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• 1993

This paper describes the results of a systematic study to determine the characteristics of particle generated from various types of asbestos containing material(ACM) and manmade fiber material(MMFM) during operations of cutting and grinding in laboratory and workplace. Tests were conducted with a specially designed glove box which allowed complete sampling of the generated asbestos fibers. Specificially, air measurements were made during ACM and MMFM installation in building. All personal air samples collected were identified by polarized light microscopy(PLM), X-ray diffraction(XRD) and scanning electron microscope with energy dispersive X-ray analysis(SEM/EDXA). Also, the samples were counted by phase contrast microscope(PCM) in order to compare the results with the permissible exposure standard for workplace. Results indicate that the characterisitcs of fibers found in the roofing sheet, the ceiling and the wall insulation boards were identical to those of asbestos, while the characteristics of fibers found in the ceiling insulation board, the floor tile and the sprayed on insulation products in parking area were identical to those of asbestos, while the characteristics of fibers found in the ceiling insulation board, the floor tile and the sprayed on insulation products in parking area were identical to those of rock wool. The concentrations of airborne fibers from various building materials cut by a grinder for 5 minutes were in the ranges of 0.09 $\sim$ 1.71 fibers/cc(f/cc). The highest concentration(1.71f/cc) was found during grinding the wall insulation board which also contains rock wool. The airborne fiber concentrations generated by installing at workplace were ranged from 0.0009 to 0.029 f/cc. All asbestos fibers from the ceiling insulation board at workplace were less than 20$\mu$m in length and more than 20% of them had the average aspect ratio greater than 20. Therefore, for the purpose of decreasing asbestos and man-made fiber concentrations at the workplace, the ceiling and wall board should use strong binding material to increase the binding force with fiber. Also, the permissible exposure standard for workplace(2.0f/cc) in Korea should be constituted below the maximum avaiable concentration measured at glove box.

• Journal of electromagnetic engineering and science
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• 제15권3호
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• pp.142-150
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• 2015

Several reports supported that continuous exposure to 60 Hz magnetic field (MF) induces testicular germ cell apoptosis in vivo. We recently evaluated duration- and dose-dependent effects of continuous exposure to a 60 Hz MF on the testes in mice. BALB/c male mice were exposed to a 60 Hz MF at $100{\mu}T$ for 24 hours a day for 2, 4, 6, or 8 weeks, and at 2, 20 or $200{\mu}T$ for 24 hours a day for 8 weeks. To induce the apoptosis of testicular germ cell in mice, the minimum dose is $20{\mu}T$ at continuous exposure to a 60 Hz MF for 8 weeks, and the minimum duration is 6 weeks at continuous exposure of $100{\mu}T$. Continuous exposure to a 60 Hz MF might affect duration- and dose-dependent biological processes including apoptotic cell death and spermatogenesis in the male reproductive system of mice. The safety guideline of the International Commission on Non-Ionizing Radiation Protection (ICNIRP) indicates that the permissible maximum magnetic flux density for general public exposure is $200{\mu}T$ at 60 Hz EMF (ICNIRP Guidelines, 2010). In the present study, we aimed to examine the expression of pro- and anti-apoptotic genes regulated by the continuous exposure to 60 Hz at $200{\mu}T$ in Sprague-Dawley rats for 20 weeks. The continuous exposure to 60 Hz at $200{\mu}T$ does not affect the body and testicular weight in rats. However, exposure to 60 Hz MF significantly affects testicular germ cell apoptosis and sperm count. Further, the apoptosis-related gene was scrutinized after exposure to 60 Hz at $200{\mu}T$ for 20 weeks. We found that the message level of endonuclease G (EndoG) was greatly increased following the exposure to 60 Hz at $200{\mu}T$ compared with sham control. These data suggested that 60 Hz magnetic field induced testicular germ cell apoptosis through mitochondrial protein Endo G.

• Advances in environmental research
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• 제6권4호
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• pp.241-254
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• 2017

This study was conducted to investigate the levels of heavy metals in twelve species of vegetables and assessment of health risk. Samples were analyzed using inductively coupled plasma mass spectrometer (ICP-MS). The ranges of Cr, Ni, Cu, As, Cd and Pb in vegetables species were 0.37-5.4, 0.03-17, 0.35-45, 0.01-2.6, 0.001-2.2, and 0.04-8.8 [mg/kg, fresh weight (fw)], respectively. The concentrations of As, Cd and Pb in most vegetable species exceeded the maximum permissible levels, indicating unsafe for human consumption. Health risks associated with the intake of these metals were evaluated in terms of estimated daily intake (EDI), and carcinogenic and non-carcinogenic risks by target hazard quotient (THQ). Total THQ of the studied metals from most of the vegetables species were higher than 1, indicated that these types of vegetables might pose health risk due to metal exposure. The target carcinogenic risk (TR) for As ranged from 0.03 to 0.48 and 0.0004 to 0.025 for Pb which were higher than the USEPA acceptable risk limit (0.000001) indicating that the inhabitants consuming these vegetables are exposed to As and Pb with a lifetime cancer risk. The findings of this study reveal the health risks associated with the consumption of heavy metals through the intake of selected vegetables in adult population of Bangladesh.