• Nuclear Engineering and Technology
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• v.56 no.5
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• pp.1679-1686
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• 2024

Graphite material plays an important role in nuclear reactors especially the high-temperature gas-cooled reactors (HTGRs) by its outstanding comprehensive nuclear properties. The structural integrity of graphite pebble fuel elements is the first barrier to core safety under any circumstances. The correct knowledge of the stiffness coefficient of the graphite pebble fuel element inside the reactor's core is significant to ensure the valid design and inherent safety. In this research, a vertical extrusion device was set up to measure the stiffness coefficient of the graphite pebble fuel element by the Institute of Nuclear and New Energy Technology (INET) of Tsinghua University in China. The stiffness coefficient equations of graphite pebble fuel elements at different temperatures are given (in a helium atmosphere). The result first provides the data on the high-temperature stiffness coefficient of pebbles in helium gas. The result will be helpful for the engineering safety analysis of pebble-bed nuclear reactors.

• Journal of Advanced Navigation Technology
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• v.27 no.4
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• pp.351-355
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• 2023

The need for Advanced LOSA arises from the limitations and drawbacks of traditional LOSA. Amended LOSA aims to address some of the shortcomings of the original methodology and make it more effective and relevant to current aviation safety needs. Some of the key reasons for developing Advanced LOSA include Enhancing the scope, Improving data collection and analysis, Providing more targeted safety recommendations. First, Traditional LOSA mainly focuses on flight deck operations, but Advanced LOSA expands the scope to include other operational areas such as cabin operations, ground handling, and maintenance. Second, Advanced LOSA can build a Forecasting System that can predict the future through data collection and data analysis. Third, Advanced LOSA aims to provide more specific and targeted safety recommendations based on the Aviation data collection and Aviation data analysis. Overall, Advanced LOSA seeks to improve aviation safety by addressing the limitations of traditional LOSA and providing a more comprehensive and effective methodology for identifying and mitigating safety risks in aviation operations.

• Analytical Science and Technology
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• v.29 no.4
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• pp.155-161
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• 2016

Distribution of various illegal or counterfeit drugs of seven approved erectile dysfunction drugs and their analogues has been increased, causing health problems such as cardiovascular disorder, tachycardia, headache, or vision disturbance. We used liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) to determine the erectile dysfunction drugs and their analogues in various counterfeit drugs. Eleven erectile dysfunction drugs and their analogues were detected, with sildenafil and its analogues being the most counterfeited compounds (73.8 %), followed by tadalafil and its analogues (25.4 %). The limits of detection (LOD) and the limits of quantitation (LOQ) of liquid-type and solid-type negative samples ranged from 0.1 to 3.3 ng/mL or ng/g and from 0.3 to 10.0 ng/mL or ng/g, respectively. The recoveries ranged from 84.3 to 112.3 % and 83.2 to 110.2 %, respectively. The contents of sildenafil and tadalafil in the various counterfeit drugs ranged from 21.0 to 947.5 mg/g and from 0.2 to 170.2 mg/g, respectively.

• Nuclear Engineering and Technology
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• v.55 no.8
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• pp.2723-2733
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• 2023

Transuranic nuclides (such as ²³⁸Pu, ²⁵²Cf, ²⁴⁹Bk, etc.) have a wide range of application in industry, medicine, agriculture, and other fields. However, due to the complex conversion chain and remarkable fission losses in the process of transuranic nuclides production, the generation amounts are extremely low. High flux reactor with high neutron flux and flexible irradiation channels, is regarded as the promising candidate for producing transuranic nuclides. It is of great significance to increase the conversion ratio of transuranic nuclides, resulting in higher efficiency and better economy. In this paper, we perform an optimization design evaluation of producing transuranic nuclides in high flux reactor, which includes optimization design of irradiation target and influence study of reactor core loading. It is demonstrated that the production rate increases with appropriately determined target material and target structure. The target loading scheme in the irradiation channel also has a significant influence on the production of transuranic nuclides.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.10a
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• pp.153-153
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• 1998

• Analytical Science and Technology
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• v.28 no.2
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• pp.86-97
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• 2015

Recently, the consumption of dietary supplements has increased because of people’s greater interest in health. Unfortunately, the sales of dietary supplements containing unauthorized substances such as drugs have also increased. We developed a rapid, accurate method for the simultaneous determination of antihistamines using liquid chromatography tandem mass spectrometry with a multiple reaction monitoring mode. The limit of detection (LOD) and limit of quantification (LOQ) of the instrument used in this method were in the ranges 0.0003-0.3 and 0.0009-0.6 µg mL⁻¹, respectively. The linearity of the method was > 0.99. The precision levels of the method were 0.1-9.8% (intra-day) and 0.3-9.6% (inter-day), and the levels of accuracy of the method were 82.7-115.0% (intra-day) and 84.3-113.0% (inter-day). The mean of recovery of the method was in the range of 83.9-117.9% and the RSD of the stability was less than 5.9%.

• 한국가스학회:학술대회논문집
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• 2003.10a
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• pp.197-202
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• 2003

• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.4049-4061
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• 2022

TRISO-coated particle fuel is widely used in high temperature gas cooled reactors and other advanced reactors. The performance of coated fuel particle is one of the fundamental bases of reactor safety. The failure probability of coated fuel particle should be evaluated and determined through suitable fuel performance models and methods during normal and accident condition. In order to better facilitate the design of coated particle fuel, a new TRISO fuel performance code named FRAT (Fission product Release Analysis Tool) was developed. FRAT is designed to calculate internal gas pressure, mechanical stress and failure probability of a coated fuel particle. In this paper, FRAT was introduced and benchmarked against IAEA CRP-6 benchmark cases for coated particle failure analysis. FRAT's results agree well with benchmark values, showing the correctness and satisfactory applicability. This work helps to provide a foundation for the credible application of FRAT.

• Nuclear Engineering and Technology
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• v.56 no.1
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• pp.147-159
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• 2024

Plutonium-238 has always been considered as the one of the promising radioisotopes for space nuclear power supply, which has long half-life, low radiation protection level, high power density, and stable fuel form at high temperatures. The industrial-scale production of ²³⁸Pu mainly depends on irradiating solid ²³⁷NpO₂ target in high flux reactors, however the production process faces problems such as large fission loss and high requirements for product quality control. In this paper, a conceptual design study of producing ²³⁸Pu in a multi-purpose high flux reactor was evaluated and analyzed, which includes a sensitivity analysis on ²³⁸Pu production and a further study on the irradiation scheme. It demonstrated that the target structure and its location in the reactor, as well as the operation scheme has an impact on ²³⁸Pu amount and product quality. Furthermore, the production efficiency could be improved by optimizing target material concentration, target locations in the core and reflector. This work provides technical support for irradiation production of ²³⁸Pu in high flux reactors.

• Analytical Science and Technology
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• v.32 no.1
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• pp.24-34
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• 2019

The safety of food is occasionally questionable, as there have been some reports of products contaminated with illegal adulterants. In this study, the presence of 16 sedative-hypnotics and sleep inducers in dietary supplements was determined by ultra-high-performance liquid chromatography with UV detection (UPLC-UV) and quadruple Orbitrap mass spectrometry (Q-Orbitrap-MS). The UPLC method was validated, providing a linearity (R2) of more than 0.999, and LODs and LOQs that ranged from 0.2 to 0.5 and 0.6 to $1.5{\mu}g\;mL^{-1}$, respectively. The repeatabilities were 0.2-8.4 % (intra-day) and 0.3-4.5 % (inter-day), and the accuracies were 89.0-117.0 % (intra-day) and 87.8-111.9 % (inter-day). The mean recoveries of the spiked samples ranged from 98.7 to 107.3 %. The relative standard deviation (%RSD) of the stability was less than 2.4 %. Using the developed method, one sedative-hypnotic compound, phenobarbital, was detected in one of the nineteen samples tested. In addition, the major characteristic fragment ions of each target compound were confirmed using Q-Orbitrap-MS for higher accuracy. Monitoring the presence of these 16 sedative-hypnotics and sleep inducers in dietary supplements should be pursued in the interest of human health, and the results of this study confirmed that the developed method has value for this application.