Radon is known to be one of the representative carcinogen materials, and may cause severe health damage to the human body with long-term exposure. Without proper treatment such as natural and mechanical ventilation, indoor radon concentration tends to increase as time passes. In this aspect, it is necessary to maintain indoor radon concentration below the domestic indoor air quality (IAQ) management standard by continuous monitoring. However, the number of practical devices which can detect radon concentration is scarce and most of the existing devices are very costly. Among such devices, the RS9A, a prototype of a radon detector, detects indoor radon concentration and is priced significantly lower compared to other existing radon detectors. In this paper, we investigated the RS9A for the continuous detection of indoor radon gas and compared its performance to a commercially available radon detector (RadonEye). We measured indoor radon concentrations at two separate sites by using both detectors simultaneously. The indoor radon concentrations measured by the aforementioned detectors revealed a high correlation. Therefore, the RS9A can be considered as an appropriate candidate for use as a continuous indoor radon monitoring system.

The reduction in solar radiation transmittance(SRT) because of dust and other foreign materials was experimentally tested in two types of greenhouses with the intent to obtain basic data for establishing maintenance and management guidelines for greenhouse cover materials. The test results in the greenhouse in Gyehwa-do estimated the amount of removed dust at 16.8– 1,021.6 mg·m-2(average: 520.7 mg·m-2), and the dust amount varied widely with the measurement points. The SRT measured in triplicate before and after dust removal ranged 68.5–80.9% and 80.9–87.2%, respectively; thus, there was an improvement in SRT by about 8.1% after dusting. In contrast, the greenhouse in Gyeongsang National University did not exhibit great fluctuations in the coefficient of determination(correlation coefficient) regardless of the daily total, average, or maximum horizontal surface radiation; the SRT gradually decreased over time. The SRT increased or decreased, showing clearly different patterns in summer and winter half years, as did the coefficients of determination(0.468–0.828). Dust was measured to be in the range 747.1– 983.1 mg·m-2(average: 840.1 mg·m-2), without great differences between the measurement points, unlike in the case of the greenhouse in Gyehwa-do. The SRT measured before and after the dust removal ranged 73.0–80.5% and 81.0–88.6%, respectively, showing an average improvement of about 7.9%. The SRT measured after washing with water ranged 88.7–90.6%, demonstrating a greater improvement with an average increase rate of 13.0%, which is 5.1% higher than the increase rate after dust removal. These results suggest that although washing with water rather than dust removal improves SRT to a greater extent(13.0% vs. 7.9%), dust removal alone is considered to provide considerable improvement in SRT. Comparison of the images of the unused film and pre-dusting film under the microscope revealed that foreign materials such as dust were adhered to the pre-dusting film, and variations were observed according to the magnification ratio and photographed area.

고준위 방사성 폐기물 처분장의 경우 폐기물의 방사성 붕괴에 의해 열이 발생되며, 암반을 통한 열전달 에 의해 처분장 주변 환경이 변화됨으로써 처분장의 안전성에 영향을 미칠 수 있다. 그러므로 지하 처분장 대기의 열전달계수를 결정하는 것은 매우 중요하다. 이에 본 연구에서는 Korea Atomic Energy Research Institute Underground Research Tunnel (KURT)에서 내부 환경 인자들의 측정을 통해 강제대류시 열전달계수를 산정하였다. 실험을 위해 KURT 내 히터구간의 막장 벽면에는 길이 2 m, 용량 5 kw의 히터를 삽 입하여 암반 내부를 90℃로 가열하였고, 외부와 연결된 급기용 팬에 의해 신선한 공기를 공급하였다. 연구 결과, 외부공기 공급 후 히터구간 대기의 기류속도는 평균 0.81 m/s로 측정되었고 레이놀즈수는 약 310,000 340,000의 값을 나타냈다. 그리고 강제대류조건에서 히터구간 내 계절별 열전달계수는 각각 여 름철 7.68 W/m2·K와 겨울철 7.24 W/m2·K의 수치를 나타냈다.

Detailed low spectral resolution observations of the spectrum have been made for three early spectral type standard stars, HR718, HR1544, HR3454, respectively, for the wavelength region 4,300 A to 7,500 A, using the Bohyunsan Optical Astronomy Observatory (BOAO) Middle- Dispersion Spectrograph. These standard stars were chosen from well-known bright northern standard stars. All of the observed long slit spectral data has been reduced and analyzed using the IRAF reduction procedure. The derived extinction coefficients are compared with the other observatory result. The derived value can be used in the determination of flux calibration of BOAO spectroscopic observation. However, until the high quality data are secured from a new series of observation in the blue region and are re-analyzed together, the extinction coefficients below the 4,000 A wavelength remains unknown.