먹노린재의 방제시기 설정을 위하여 서식지 내 발생 양상을 조사하였다. 전라남도를 중심으로 돌발 대량 발생 한 먹노린재의 발생 조사는 2023년도 벼의 모내기가 완료된 시점부터 전남 곡성군 석곡면과 여수시 화양면 일대 의 친환경단지에서 주 1회 실시하였으며, 벼의 수확이 완료되는 시점까지 진행될 예정이다. 금년도 발생 조사 결과는 지난 2021년도 결과와 비교하여 분석하고자 하였다. 현제까지의 결과, 여수시의 친환경단지 내 먹노린재 의 발생은 모내기가 완료된 이 후 2주 경과 시점에서 발견되었으며, 곡성군은 4주 경과 시점에서 발견되었고, 발생 최고점은 여수시의 경우 모내기 후 6주 경과 시점으로, 곡성군의 경우 5주 경과 시점으로 나타났다. 먹노린재 의 대발생이 지속되던 2021년도의 결과와 비교하였을 때, 2023년도 결과도 유사한 것으로 나타났다. 이에 따라, 먹노린재 친환경제재 살포 시기는 모내기 후 2주 경과 시점이 적절한 것으로 나타났으며, 2차 방제 시점에 대해서 는 추가 조사를 통해서 제안하고자 한다.

Some of the metal waste generated from KEPCO NF is being disposed of in the form of ingots. An ingot is a metal that is melted once and then poured into a mold to harden, and it is characterized by a uniform distribution of radioactive material. When measuring the uranium radioactivity in metal ingot with HPGe detector, 185.7 keV of U-235 is used typically because most gamma rays emitted at U-235 are distributed in low-energy regions below 200 keV. To analyze radioactivity concentration of U-235 with HPGe detector more accurately, self-attenuation due to geometrical differences between the calibration source and the sample must be corrected. In this study, the MCNP code was used to simulate the HPGe gamma spectroscopy system, and various processes were performed to prove the correlation with the actual values. First an metal ingottype standard source was manufactured for efficiency calibration, and the GEB coefficient was derived using Origin program. And through the comparison of actual measurements and simulations, the thickness of the detector’s dead layers were defined in all directions of Ge crystal. Additionally instead of making an metal ingot-type standard source every time, we analyzed the measurement tendency between commercially available HPGe calibration source (Marinelli beaker type) and the sample (metal ingot type), and derived the correction factor for geometry differences. Lastly the correction factor was taken into consideration when obtaining the uranium radioactivity concentration in the metal ingot with HPGe gamma spectroscopy. In conclusion, the U-235 radioactivity in metal ingot was underestimated about 25% of content due to the self-attenuation. Therefore it is reasonable to reflect this correction factor in the calculation of U-235 radioactivity concentration.

We introduce the Transformable Reflective Telescope (TRT) kit that applies an aluminum profile as a base plate for precise, stable, and lightweight optical system. It has been utilized for optical surface measurements, developing alignment and baffle systems, observing celestial objects, and various educational purposes through Research & Education projects. We upgraded the TRT kit using the aluminum profile and truss and isogrid structures for a high-end optical test device that can be used for prototyping of precision telescopes or satellite optical systems. Thanks to the substantial aluminum profile and lightweight design, mechanical deformation by self-weight is reduced to maximum 67.5 μm, which is an acceptable misalignment error compared to its tolerance limits. From the analysis results of non-linear vibration simulations, we have verified that the kit survives in harsh vibration environments. The primary mirror and secondary mirror modules are precisely aligned within 50 μm positioning error using the high accuracy surface finished aluminum profile and optomechanical parts. The cross laser module helps to align the secondary mirror to fine-tune the optical system. The TRT kit with the precision aluminum mirror guarantees high quality optical performance of 5.53 μm Full Width at Half Maximum (FWHM) at the field center.

Even in an era where 8-meter class telescopes are common, small telescopes are considered very valuable research facilities since they are available for rapid follow-up or long term monitoring observations. To maximize the usefulness of small telescopes in Korea, we established the SomangNet, a network of 0.4{1.0 m class optical telescopes operated by Korean institutions, in 2020. Here, we give an overview of the project, describing the current participating telescopes, its scientic scope and operation mode, and the prospects for future activities. SomangNet currently includes 10 telescopes that are located in Australia, USA, and Chile as well as in Korea. The operation of many of these telescopes currently relies on operators, and we plan to upgrade them for remote or robotic operation. The latest SomangNet science projects include monitoring and follow-up observational studies of galaxies, supernovae, active galactic nuclei, symbiotic stars, solar system objects, neutrino/gravitational-wave sources, and exoplanets.

막 생물 반응기(MBR)에서, 활성화 된 슬러지는 생물학적 성분을 분해하고 막 공정은 이 부유 물질인 박테리아를 분리시킨다. 그러나 MBR에서의 주요 문제는 ‘막 오염’이다. 이 리뷰에서는 ‘막 오염’을 극복하기 위하여 제시된 ‘복합막’을 논의하고 있다. ‘복합막’은 탄소 또는 비탄소 재료 포함하는 막으로 분류할 수 있다. 이 복합막의 친수성은 그래핀, 산화그래핀 (GO) 및 탄소 나노 튜브 또는 그들의 변형 된 부분을 깨끗한 막에 도입시킬 때 향상된다. 이산화규소(SiO2) 또는 이산화티타 늄(TiO2)과 같은 무기 물질 또한 막의 물 흐름을 증가시키기 위해 복합막 형성에 통합된다.