氦离子辐照烧结碳化硅损伤效应研究

利用中国科学院近代物理研究所320 kV高压平台提供的氦离子辐照烧结碳化硅,辐照温度从室温到1 000 ℃,辐照注量为1015~1017 cm-2。辐照完成后,进行退火处理,然后开展透射电子显微镜、拉曼光谱、纳米硬度和热导率测试。研究发现,烧结碳化硅中氦泡形核阈值注量低于单晶碳化硅。同时,氦泡形貌和尺寸与辐照温度、退火温度有关。另外,对辐照产生的晶格缺陷、元素偏析进行了研究。结果表明,辐照产生了大量的缺陷团簇,同时氦泡生长也会发射间隙子,在氦泡周围形成间隙型位错环。在晶界处,容易发生碳原子聚集。辐照导致材料先发生硬化而后发生软化,且热导率降低。     

Experiments on the Twisted Vortex State in Superfluid 3He-B

We have performed measurements and numerical simulations on a bundle of vortex lines which is expanding along a rotating column of initially vortex-free ³He-B. Expanding vortices form a propagating front: Within the front the superfluid is involved in rotation and behind the front the twisted vortex state forms, which eventually relaxes to the equilibrium vortex state. We have measured the magnitude of the twist and its relaxation rate as function of temperature above 0.3T _c. We also demonstrate that the integrity of the propagating vortex front results from axial superfluid flow, induced by the twist.      

Elucidating the degradation mechanism of 0.5Gd2Zr2O7·0.5TRPO under multi-energy He ion irradiation

Gd₂Zr₂O₇ has long been considered as one of the most promising waste forms and has attracted broad interest in the field of nuclear waste immobilization. This work utilizes multi-energy He-irradiation to study the microstructural and helium bubble evolution of Gd₂Zr₂O₇ immobilizing with the final waste after partitioning high-level liquid waste by using the trialkyl phosphide (TRPO waste, the waste load is 50 wt%) in an experimentally feasible time frame. Interestingly, at less than 40 nm below the He-irradiated surface (Region I), there are a significant number of well-aligned large spherical He bubbles with diameters ranging from 5 to 25 nm and a severely amorphous structure. The mechanism of these novel phenomena may be related to enhanced migration rate of vacancies by high electronic energy loss, promoting the combination of vacancies with relatively high-density He atoms, suppressing the recombination-annihilation of vacancies and interstitial atoms, thus accelerating the irradiation amorphization.     

Clean energy transition in the Turkish power sector: A techno-economic analysis with a high-resolution power expansion model

The Turkish power sector achieved rapid growth after the 1990s in line with economic growth and beyond. However, domestic resources did not support this development and therefore resulted in a high dependency on imported fossil fuels. Furthermore, the governments were slow off the mark in introducing policies for increasing the share of renewable energy. Even late actions of the governments, as well as significant decreases in the cost of wind and especially solar technologies, have recently brought the Turkish power sector into a promising state. A large-scale generation-expansion power-system model (TR-Power) with a high temporal resolution (hours) is developed for the Turkish power generation sector. Several scenarios were analyzed to assess their environmental and economic impacts. The results indicate that a transition to a low-carbon power grid with around half of the electricity demand satisfied by renewable resources over 25 years would be possible, with annual investments of 3.97–6.88 billion in 2019 US$. Moreover, TR-Power indicates that the shadow price of CO₂ emissions in the power sector will be around 17.1 and 33.8 $/per tCO2 by 2042, under 30% and 40% emission reduction targets relative to the reference scenario.     

<史记.天官书>星象(待续)--天人合一的幻想基准

《史记·天官书》成于西汉中期偏后 ,成为自汉代以后历代史书记载星象的源头。其记载内容是以北天极附近的中宫以及七政 (日、月、五大行星 )移动的背景星区 (黄赤道带 )即东、南、西、北四宫星象为基准 ,是入史以来天文知识总汇的杰出代表 ,在天文学史学方面具有承上启下的关键作用。     

Microstructural evolution,swelling and hardening of CVD-SiC induced by He ions irradiation at 650 °C

In the present study, chemical vapor deposited (CVD) SiC samples were irradiated by 500 keV He ions to different doses at 650 °C. The microstructural evolution, surface swelling and nanohardness change caused by irradiation versus He ion dose were investigated using TEM, AFM and nanoindentation. Results showed that a high number density of He bubbles and dislocation loops were formed in the sample irradiated to the high dose, resulting in a swelling of 1.53%. Meanwhile, the hardness of the samples increased after He ions irradiation, which was attributed to the pinning effect of the irradiation induced defects and bubbles. The irradiation hardening degree increased and tended to be saturated with the increasing He ion dose.     

氖中微量组分气相色谱测量分析方法与验证

为测量聚变堆固态氚增殖剂堆内辐照氚增殖剂的产氚速率，除用常规电离室之外，本研究建立了Ne载气的高精度气相色谱在线检测分析方法，通过测量产氚回路中的氦产生量，验证系统中产生的氚量，从而为聚变堆固态包层产氚包层增殖剂材料辐照产氚性能提供一种新的产氚速率测量验证方法。本工作通过研制含有三个检测器、五个色谱柱的气相色谱分析系统，建立了Ne中微量⁴He、H₂及杂质组分的色谱检测分析方法，并完成了实时在线检测的验证实验。结果表明，研发的色谱分析系统可实现高纯Ne中4He、H₂及杂质组分的检测分析，H₂、⁴He检测限可分别达到1.0×10^-6、5.9×10^-6，各组分含量及峰面积的相对标准偏差(sr)均小于5.0%(n=6)，线性相关系数(r²)均大于0.99，说明检测方法重复性好。根据Ne中多组分气体的在线检测验证实验可知，单时段和多时段内的测量重复性均较好，可为辐照产氚考核系统中的产氚速率验证提供分析手段，进而为正式入堆得到辐照数据和氚衡算提供技术支持。     

《史记@天官书》星象(续完)——天人合一的幻想基准

《史记·天官书》成于西汉中期偏后 ,成为自汉代以后历代史书记载星象的源头。其记载内容是以北天极附近的中宫以及七政 (日、月、五大行星 )移动的背景星区 (黄赤道带 )即东、南、西、北四宫星象为基准 ,是入史以来天文知识总汇的杰出代表 ,在天文学史学方面具有承上启下的关键作用。