Nuclear Forensics is recognized as a essential component in the nuclear non-proliferation verification sector by the international community. It is being advanced under the leadership of the IAEA, the U.S., and the EU. Both the U.S.’s Lawrence Livermore National Laboratory (LLNL) and the international collaborative organization, the Nuclear Forensics International Technical Working Group (ITWG), have proposed to establish a relationship between the production timing and radiochronometry of nuclear materials or samples to utilize in the field of nuclear forensics. Radiochronometry of nuclear materials is calculated based on the Bateman equation, incorporating factors with uncertainties derived from tests, experiments, and analyses. The results from the nuclear activity radiochronometry also encompass uncertainties, affecting their reliability. This study examined the mathematical uncertainty calculations related to the results of nuclear activity radiochronometry, focusing on calculation methods, contribution rates per factor, and sensitivities. Uncertainty factors for the Bateman equation-based radiochronometry were observed in the decay constants for each nuclide type and the uncertainty in the radioactive ratio of the tracer nuclide. The sensitivity for each factor revealed that the uncertainty in the radioactive ratio of the signature nuclide contributed more significantly than the uncertainty in decay constants for each nuclide type. Each factor displayed a distinct sensitivity curve relative to the radioactive ratio. As it approaches a radioactive equilibrium, the sensitivity tends to increase infinitely, indicating a corresponding trend of infinite increase in uncertainty. Because the time and curve shape to reach radioactive equilibrium vary depending on the signature nuclide, it’s essential to choose an appropriate signature nuclide based on the anticipated period and analysis requirements for nuclear activity radiochronometry. However, radiochronometry using mathematical methods is limited to the relationship between parent and daughter nuclides, presenting the potential for underestimation of uncertainty factors like decay constants. Future research will need to focus on uncertainty calculation methods through computational simulations, especially using the Monte Carlo method, to overcome the limitations of mathematical approaches and potential underestimations.

In this study, the MoS2 nanoparticles grown on crumpled 3D graphene microball (3D GM–MoS2) was synthesized using a microfluidic droplet generator with thermal evaporation-driven capillary compression and hydrothermal reaction. The morphology and size of 3D GM–MoS2 are controlled by the concentration of nano-sized graphene oxide (GO) and the flow rate of oil phase on the droplet generator. The 3D GM–MoS2 with fully sphere-shape and uniform size (~ 5 μm), and homogeneous growth of MoS2 nanoparticles could be synthesized at the flow rate of the oil phase of 60 μL/min with the optimized GO concentration of 1.0 mg/mL, and ( NH4)2MoS4 concentration of 2.0 mg/mL.

소나무재선충은 소나무에이즈라고 불리는 소나무해충으로서 전국적으로 큰 피해를 끼치고 있다. 최근 소나무재선충 피해는 경북지역의 경주 및 포항지역에 많이 발생하고 있다. 특히 경주지역에는 역사적인 유적지 및 고분공원이 많은데 이 지역의 소나무 숲에 재선충 피해가 확산되고 있어서 역사적 가치뿐만 아니라 관광산업에 큰 피해가 예상된다. 재선충 피해를 줄이기 위하여 재선충 감염목에 대한 신속한 제거작업이 필요한데 이에 대한 진단이 어려운 실정이다. 본 연구에서는 LAMP-PCR 진단키트를 이용하여 경주 고적지 지역의 재선충 감염이 의심되는 소나무를 진단하였다. 경주남산 및 불국사부근 7개 지역에서 재선충 감염 의심목으로부터 시료를 채취하여 조사해 본 결과 약 50%의 소나무에서 양성반응을 나타내었다. 본 연구를 통하여 경주 고적지의 재선충 감염여부를 신속하게 진단할 수 있었고 경주 유적지의 재선충 피해를 억제하는데 기여할 수 있을 것으로 판단한다.