The seismic deformation method is conventionally used as a seismic design for a multi-utility tunnel in Korea. In the seismic deformation method, the soil ground’s natural period is one of the most critical factors for calculating the ground displacement using cosine functions. Correction factors for the natural period and shear wave velocity have been used to consider the non-linearity of dynamic soil properties. However, the correction factors have been issued because the correction factors have not been sufficiently studied to consider Korea’s regional conditions. This paper aims to evaluate the natural periods for the seismic deformation method considering Korea’s ground conditions. Ground response analysis was performed using seven real earthquake records on twelve sites with different soil conditions where actual multi-utility tunnels are installed. As a result, natural periods of the sites were analyzed and new correction factors were proposed according to seismic performance and Korea’s regional conditions.

In this study, we develop and propose damping correction factors for the Korean standard design spectra. The newly proposed Korean standard design spectra has been given only for 5% damping ratio. But in practice, engineers need design spectra for damping values other than 5%. To obtain design spectra for various damping values from the standard spectra, damping correction factors are derived. These factors modify the shape of design spectra in accordance with the damping ratio. Response spectra for various damping values are calculated from the earthquake records that had been used to calculate standard design spectra. They consist of 55 records from 18 earthquakes occurred in overseas intraplate regions and Korea. The regressed spectra for the damping values ranging from 0.5% to 50% are compared with standard spectra at three regions acceleration, velocity and displacement sensitive regions. The regression analysis of these data rendered formula for damping correction factors. Finally, a single formula for damping correction factors is recommended that is valid for both horizontal and vertical design spectra and that is applicable to the entire range of periods. One thing to note that recommended damping correction factors is valid for the design spectrum of the rock grounds because the design spectra was developed based on the earthquake records of the rock ground.

We report results of investigation of amplitude calibration for very long baseline interferome- try (VLBI) observations with Korean VLBI Network (KVN). Amplitude correction factors are estimated based on comparison of KVN observations at 22 GHz correlated by Daejeon hardware correlator and DiFX software correlator in Korea Astronomy and Space Science Institute (KASI) with Very Long Base- line Array (VLBA) observations at 22 GHz by DiFX software correlator in National Radio Astronomy Observatory (NRAO). We used the observations for compact radio sources, 3C 454.3, NRAO 512, OJ 287, BL Lac, 3C 279, 1633+382, and 1510−089, which are almost unresolved for baselines in a range of 350-477 km. Visibility data of the sources obtained with similar baselines at KVN and VLBA are se- lected, fringe-fitted, calibrated, and compared for their amplitudes. We find that visibility amplitudes of KVN observations should be corrected by factors of 1.10 and 1.35 when correlated by DiFX and Daejeon correlators, respectively. These correction factors are attributed to the combination of two steps of 2-bit quantization in KVN observing systems and characteristics of Daejeon correlator.

Base Balance Technique은 건축물의 하중과 변위 및 가속도와 같은 응답들을 구하기 위한 기본적인 풍동실험기법으로 사용되어 왔다. 이 기법은 선형적인 형상함수의 내제된 가정으로 수행함으로써, 밑면 전도모멘트로 일반화된 하중을 추정할 수 있다. 그러나 초고층건물은 다수의 풍방향진동에 대한 형상함수들을 가지고 있다. 본래의 초고층건물의 기본적인 형상함수는 선형적이지 않으므로 풍동실험이나 선형적인 해석의 결과로부터 약간의 조정이 필요하다. 본 연구에서는 풍동실험의 데이터를 이용하여 풍방향응답의 보정계수를 제안한다. 그리고 건물의 높이와 너비, 건물주기 등으로부터 보정계수의 요인들을 이해할 수 있다.

CHIME 연대측정을 위한 전자현미분석(EPMA)에서는 통상적으로 핵 연료 물질 등 구하기 어렵고 관리에 민감한 표준 물질을 사용하므로 이를 구하지 못하는 실험실에서는 적용에 어려움이 있다. 이 연구에서는 이러한 표준 물질을 대신할 수 있는 새로운 실험실 표준법을 제시한다. CHIME 연대 측정이 원활하게 이루어지고 일련의 표준 물질이 잘 구비된 실험실에서 X선 세기가 균질함이 확인된 모나자이트와 같은 광물편을 대상으로 보정 상수를 정확히 구하고, Th, U 등의 특성 X선 세기를 측정해두면, 다른 실험실에서는 단지 광물편의 특성 X선 세기를 측정하는 것만으로 바로 사용할 수 있는 표준 물질로 활용할 수 있다. 이 기법은 전자 현미 분석에서 화학성분과 X선 간섭 보정 계수의 결정에 필요한 표준 물질로 모두 활용이 가능하며, 광물 표준 물질의 복잡한 화학 성분에 대해 독립적이다.

본 연구에서는 대기 중 황성분을 채취하는데 가장 널리 활용되는 방법 중의 하나인 테들러 백 방식의 채취와 관련된 오차요인을 여러 가지 관점에서 검정하고자 하였다. 이를 위해, 표준시료를 백과 백간에 이동시켜 주므로서, 백의 벽면을 통해 초래될 수 있는 성분별 손실율을 비교하였다. 상대습도 0 %, 실온 조건에서 실험한 결과, 황화수소와 멀캡턴과 같은 성분들은 백과의 접촉이 일어나면서, 20 %에 가까운 손실율이 확인되었다. 반면, 상대적으로 이들에 비해 반응성이 높지 않은 DMS, DMDS와 같은 성분들도 10 %내외의 손실율이 확인되었다. 이들 성분의 정확한 정량을 위해서는 테들러 백의 흡착손실 등에 대한 특성을 정확하게 파악하는 것이 중요하다. 특히, 습도나 온도와 같은 환경조건의 변화에 대한 고려도 동시에 수반되어야 할 것이란 점을 확인할 수 있었다.

This study was conducted to propose a strength correction factor to compensate the strength delay at designed age caused by the temperature drop in low temperature condition. Strength correction factors due to temperature drop T28 were provided using the constant function model.

This study investigated the association between PM2.5 concentrations obtained with portable real-time monitors and those obtained with gravimetric methods in national urban air-quality monitoring sites in Seoul, South Korea. We used the SidePak AM510 Personal Aerosol Monitor (TSI Inc., 500 Cardigan Road Shoreview, MN) and DustTrak DRX 8533 (TSI Inc., 500 Cardigan Road Shoreview, MN) as portable real-time monitors for measuring PM2.5 concentrations and compared these values with those measured with the PMS-103 or SEQ 47/50 models operated by Federal Reference Method (FRM) or the European Committee for Standardization(ECS), respectively, in national urban air-quality monitoring sites in Seoul. Measurements were conducted every other day in the winter and spring seasons of 2014. The estimated daily mean concentrations of PM2.5 ranged between 13.4 and 161.9 μg/m3 using AM 510 and between 22.0 and 156.0 μg/m3 using DustTrak. The Spearman correlation coefficient for PM2.5 concentrations between AM 510 and gravimetric results was 0.99, and the correlation between DustTrak and gravimetric results was 0.87. The correction factor suggested was 0.42 and 0.29 for AM 510 and DustTrak, respectively. We found that PM2.5 concentrations measured with real-time monitors could overestimate true PM2.5 concentrations and therefore the application of a correction factor (0.43) is strongly suggested for quantification when Real-time monitors were operated of PM2.5 levels at urban atmospheric environment of South Korea.