共查询到20条相似文献,搜索用时 15 毫秒
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B. N. Kolbasov 《Journal of Fusion Energy》1997,16(3):285-290
The paper seeks to provide a summary report of observations and results of some Russian fusion safety studies performed in 1996. Release of tritium and helium from neutron irradiated beryllium at relatively high neutron fluences has a burst nature. With the growth of the beryllium temperature-increase rate to 90 K/s, the temperature of tritium burst release decreases from 800 to 450–500°C and for helium decreases from 1200 to 500°C. Characterization of carbon and tungsten dust produced in experiments simulating plasma disruptions revealed that dust particle distribution of sizes for graphites and carbon fiber composites has a bimodal nature with maxima in the range of 0.01–0.03 and 2–4 m for composite UAM and in the range of 0.14–0.18 and 2–4 m for graphite MPG-8. Chemical reactivity of beryllium with air was studied as well. A mathematical model for beryllium weight gain under its chemical interaction with air at temperatures of 700–800°C as a function of beryllium porosity, temperature, and interaction duration was developed. 相似文献
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Several changes to the focus of Computational Intelligence in Nuclear Engineering have occurred in the past few years. With earlier activities focusing on the development of condition monitoring and diagnostic techniques for current nuclear power plants, recent activities have focused on the implementation of those methods and the development of methods for next generation plants and space reactors. These advanced techniques are expected to become increasingly important as current generation nuclear power plants have their licenses extended to 60 years and next generation reactors are being designed to operate for extended fuel cycles (up to 25 years), with less operator oversight, and especially for nuclear plants operating in severe environments such as space or ice-bound locations. 相似文献
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On the basis of the previously described increase in internal friction in uranium during heating, a semiquantitative evaluation was made of the dependence of increase in internal friction on the rate of heating, frequency and amplitude of vibrations. The results of the calculations agree satisfactorily with data obtained experimentally. A study was made of the effect of the initial state of the specimen on the increase in internal friction at the initial stages of heating. 相似文献
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Momo Takada Toshihiro Yamada Teruhiko Takahara Satoru Endo Kenichi Tanaka Tsuyoshi Kajimoto 《Journal of Nuclear Science and Technology》2017,54(4):452-458
Downward migration of 137Cs in soils was studied in three mixed deciduous forests c.a. 40 km northwest of the Fukushima Daiichi Nuclear power plant (FDNPP), Japan. We selected three different types of forest regarding to environmental condition such as slope inclinations and snow coverage conditions at the time of deposition. We examined temporal changes in the vertical distribution of 137Cs from litter layers to 10 cm soil depth for two years (2.3 to 4.3 years after the FDNPP accident in 2011). At all three study sites, the 137Cs in the litter layer had largely migrated to surface soil by 2013. After 2014, about 80% of the 137Cs in forest soils (litter layer to 10 cm soil depth) remained within 0–5 cm soil layer. The vertical distribution had not changed substantially since 2014, suggesting that changes to the downward migration rates of 137Cs in soils drastically decreased with time. In addition, small amounts of migrating 137Cs could not be detected by the present method because there was a large spatial variation in the distribution of soil 137Cs. The results showed similar patterns of soil 137Cs distribution among the three study sites although there were differences in the environmental conditions. 相似文献
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报道了广东省商检中心放射性检验室开展的广东进出口食品中的放射性检验工作。介绍了检验工作采用仪器的主要性能及应用;给出了分析测量方法和探测下限以及实验的质量保证措施,并给出了检验室测量的广东省几种食品中的放射性含量范围,测量结果与我国食品中放射性活度变化范围大体一致。 相似文献
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Deng Ke Wang Ling Xia Zheng-Hai Ma Yu-Hua Qin Lai-Lai Zhang Qin Liu Jia-Yu Yao Jian Liu Wei 《核技术(英文版)》2018,29(5):1-7
Beamline BL17 U1 at Shanghai Synchrotron Radiation Facility is an energy-tunable macromolecular crystallography beamline that has been in user operation since 2009. Growing demand from the user community for a small beam and related experimental methods have motivated upgrades of the devices in the endstation.Minibeam modes have already been developed for operation. A self-integrated diffractometer reduces the sphere of confusion of the rotatory axis to 1μm. The new diffractometer is equipped with an upgraded on-axis viewing system that can improve the resolving power. Additionally,the area detector was also upgraded to the newest generation of detectors, the EIGER X 16 M, which can collect data at 133 Hz. After these upgrades, the endstation became virtually new. This paper covers the upgrade of the endstation devices and gives the first data collection results. 相似文献
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2010年,美国铀矿总共施工7 209个钻孔,总进尺1 493 520 m;生产铀1 628.55t;铀矿业总支出费用为2.773亿美元,其中铀矿地勘费支出为3 450万美元,占铀矿业总费用的12.44%.铀矿地勘钻探费用为4 460万美元,占铀矿业总费用的16.08%. 相似文献
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自噬对鼻咽癌(Nasopharyngeal carcinoma,NPC)具有抑瘤和促瘤双重作用。自噬在NPC发生、发展及转归中起重要作用:低水平、基础自噬有利于细胞的自我保护与新陈代谢,是NPC放、化疗抵抗的重要因素之一;高水平、过度自噬则可导致自噬性细胞死亡,是基于自噬靶点的NPC治疗基础。自噬剂的研发与应用是实现自噬水平调控的关键环节,自噬抑制剂或自噬诱导剂可增敏NPC放、化疗甚至诱导其自噬性细胞死亡,但其作用机理颇为复杂且迄今尚未完全明了。本文着重综述自噬与NPC放疗研究进展,并探讨自噬作为新靶点的NPC治疗前景,尤其X射线作为自噬剂以诱导NPC发生治疗性的自噬性细胞死亡。 相似文献
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Ke Deng Ling Wang Zheng-Hai Xia Yu-Hua Ma Lai-Lai Qin Qin Zhang Jia-Yu Liu Jian Yao Wei Liu 《核技术(英文版)》2018,(5)
Tritium concentrations in precipitation can be used as a criterion to evaluate the tritium baseline of the environment. The tritium concentration in precipitation in Shanghai during 2014-2015 was determined. Values ranged from 0.68 ± 0.04 to 4.11 ± 0.39 Bq/L, and it showed a decreasing trend compared with historical data; however,the values were slightly higher than the natural background tritium level. Additionally, the tritium concentration shows a seasonal variation: It was higher in autumn and winter and lower in summer and spring. A comparison of concentrations in precipitation in Shanghai and around the Qinshan Nuclear Power Plant reveals no correlation,implying that the nuclear power plant operations may not affect the environment of Shanghai. Thus, the raised tritium concentrations in Shanghai might be due to the effects of monsoons, spring leak, raindrop, or other activities that generate tritium there. Those activities may include chemistry research that uses tritium as a tracer. 相似文献
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分别采用高效液相色谱法、紫外分光光度法对OxLDL-Ab进行定性、定量分析,评价~(125)I-OxLDL-Ab在正常动物和动脉粥样硬化模型动物的体内分布。正常动物采用昆明小鼠,模型采用载脂蛋白E基因敲除的小鼠(apolipoprotein E-deficient mice,ApoE~(-/-))。高效液相色谱条件为:磷酸缓冲液(PB,0.2 mol/L,pH=7.4)为流动相,流速1.0mL/min,检测波长220nm;紫外分光光度法测得蛋白浓度的标准曲线为:y=0.664 5x-0.008 3,r2=0.999 7。~(125)I-OxLDL-Ab在正常小鼠体内分布实验结果表明:除甲状腺外,各器官的放射性摄取随时间延长而减少,无明显浓集;在注射~(125)I-OxLDL-Ab后1d各器官代谢消除超过2/3,7d后血液中完全清除。~(125)I-OxLDL-Ab在ApoE~(-/-)鼠体内的分布实验中采用w=2%的KI溶液封闭了甲状腺,消除了甲状腺高摄取的影响;靶器官肺有较高放射性摄取,且在注射后4~8h显示出放射性浓集;除血外,其它各器官的靶器官/非靶器官的放射性摄取比值(T/NT)均大于1,其中T/Mu(肌肉)8,显示出~(125)I-OxLDL-Ab对靶器官有一定的选择性。标记抗体的体内靶向性是显像研究中至关重要的一环,要进一步用于动脉粥样硬化早期显像诊断,还需进一步提高靶器官/非靶器官的放射性摄取比值,提高其在体内与其抗原的亲和性。 相似文献
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Ken-ichi Fukumoto Ryota Fujimura Michio Yamawaki Yuji Arita 《Journal of Nuclear Science and Technology》2015,52(10):1323-1327
The effects of air on the corrosion of Hastelloy-N alloys in molten salt coolant containing fission product elements were investigated to determine the safety of structural materials in high-temperature reactors cooled with fluoride salt. Corrosion tests of Hastelloy-N in the molten fluoride salt FLiNaK in an alumina crucible and a graphite crucible under argon gas or air were performed at 773–923 K for 100 h. The depth of corrosive attack, as well as the extent of chromium and molybdenum depletion, increased with increasing temperature. The extent of Hastelloy-N corrosion in molten salt under air was significantly greater than under argon gas. The effect of adding the impurity cesium iodide to molten salt containing nuclear waste fuel on the corrosion behavior was negligible. 相似文献
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The results of an experimental investigation of explosive-emission plasma dynamics in an ion diode with self-magnetic insulation are presented. The investigatio... 相似文献
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XU Jiehua ZHANG Zikang CHENG Muhua WANG Ping WU Chunxing SHAN Hong 《核技术(英文版)》2007,18(5):294-297
The study was to evaluate factors affecting outcome of 131I therapy in hyperthyroidism for optimizing the method. Data from 213 patients who received 131I treatment from July 2003 to July 2005 in our department were retrospectively analyzed. Factors possibly contributing to the outcome of the 131I therapy were analyzed, including gen-der, age, history of antithyroid drug, thyroid volume, duration of disease and radioactive iodine uptake rate. Multivariate analysis was done. The rates of euthyroidism and hypothyroidism were 69% and 8.5%, respectively, after one time 131I therapy. Multivariate analysis of the patients showed no statistically significant factors affecting the outcome of 131I therapy. The study showed that 131I dose can be directly calculated, and this simplifies the dose-determined method and individualizes the therapy. 相似文献