Ab initio study of helium in Li4SiO4 crystals: Electronic properties,migration, and vacancy capture mechanism

Li₄SiO₄ crystal is a candidate material for tritium breeder material. Vacancy defects and He atoms will be produced in the crystal after neutron irradiation in fusion reactor. In previous research, we learned vacancy defects mainly include V_O⁰, V_O²⁺, and V_Li⁰, meanwhile, He atoms are easy to migrate and aggregate in the crystal. In order to understand the relationship between vacancy defects and He atoms, we use density functional theory (DFT) to study the interaction mechanism between vacancy and He atom. The results show that the local stable sites of He atoms are related to the surrounding charge distribution. V_O²⁺ and V_Li⁰ can capture interstitial He atoms, and it is difficult to escape the vacancies, thereby increasing the nucleation center of He atoms. V_O⁰ promotes the diffusion of He atoms in the interstitial space, which will cause small helium bubbles to merge more easily.     

Matrices pattern using FIB; ‘Out‐of‐the‐box’ way of thinking

Focused ion beam (FIB) is an extremely valuable tool in nanopatterning and nanofabrication for potentially high‐resolution patterning, especially when refers to He ion beam microscopy. The work presented here demonstrates an ‘out‐of‐the‐box’ method of writing using FIB, which enables creating very large matrices, up to the beam‐shift limitation, in short times and with high accuracy unachievable by any other writing technique. The new method allows combining different shapes in nanometric dimensions and high resolutions for wide ranges.     

和而不同--国务院参事室研究中心设计

国务院事室研究中心工程，地处东交民巷这一历史信息密集街区。笔者移植“和而不同”这一传统理念应用于历史街区局部更新，从建筑形式、整体比例、细部尺度、材料选择几个方面努力，基本达到了预期的设计目标：融合与共生。     

氦中氙、六氟化硫气体标准物质研制

论述了氦中氙、六氟化硫气体标准物质的制备方法、稳定性参考值、不确定度计算方法,证明达到国家二级气体标准物质要求。该研制方法可行,最值准确可靠。     

（U-Th）/He定年技术在矿床年代学研究中的应用前景

（U-Th）/He定年技术是近年来快速发展起来的一种新的放射性同位素定年方法,已经在基础地质研究领域得到了广泛应用。在介绍（U-Th）/He定年方法技术原理的基础上,对此技术发展现状和地质应用研究成果做出简要总结,并对用该方法研究金属和非金属矿床成矿时代、研究金属矿床后期改造和矿床揭顶时代的可行性进行探讨。     

石墨镶嵌Co纳米晶的形成及其特性

用直流碳弧法在阳极石墨棒中加入金属Ｃｏ产生石墨镶嵌Ｃｏ纳米晶,研究在复合石墨棒中加入不同的Ｃｏ含量对石墨镶嵌Ｃｏ纳米晶的形貌、结构特性及晶粒尺寸分布的影响,探讨石墨镶嵌Ｃｏ纳米晶的形成原因及碳弧法中氦气压力和Ｃｏ含量对掺Ｃｏ阳极石墨棒所产生的碳灰的Ｃ６０／７０产率的影响。结果表明,复合阳极棒中的Ｃｏ含量决定了石墨镶嵌Ｃｏ纳米晶的数量和晶凿直径分布,碳弧法中的Ｈｅ气压力仍是影响掺Ｃｏ阳极棒所产生的碳     

垂直偏振态He-Ne激光自混合干涉的实验研究

从实验上研究了频率分裂激光器中偏振态相互垂直的o光和e光的自混合干涉现象,因为o光和e光之间的模竞争效应,所以在o光和e光的反馈曲线中,最大值和最小值相互对应,在一个周期中,最大值出现的次数是一般反馈曲线的2倍,幅值的变化也是一般反馈曲线的2倍。     

郑和下西洋的出国门——五虎门考辨

对于郑和历次下西洋的出国门, 在国内外郑和研究著述中, 尚未见专文论述, 而在这个问题上, 自明朝 至今还存在一些误解在传讹, 很有必要澄清。通过考证, 论定郑和下西洋的出国门应是五虎门, 而非其他港口。对五虎门在海疆中地理形势和其地名渊源及古今行政隶属进行了考辩, 对五虎门的古今功能进行了考证, 建议在地方命名上保持著名国门的历史名称。     

Frictional Effects in Thin 3He Films

The recent high-precision torsional oscillator experiments of Casey et al. involving thin films of normal liquid ³He showed that the film decouples from the substrate with a time constant which is proportional to T ⁻¹ where T is the absolute temperature. We interpret this experiment by adapting a theory due to Meyerovich which was developed for dilute ³He-⁴He mixtures flowing between two relatively smooth plates. The analysis of the experiment confirms the central idea that varies as T ⁻¹. The variation of with film thickness, d, is affected by the change in the shape of the free surface of the film, due to van der Waals forces, as the film becomes thinner.     

Test results after refurbish of cryogenic system for smiles

Superconducting Sub-millimeter-wave Limb-Emission Sounder (SMILES) is to be operated aboard the Japanese Experiment Module (JEM) of the International Space Station (ISS) in 2009. SMILES uses two superconductor-insulator-superconductor (SIS) mixers for sub-millimeter-wave atmospheric observation and they are cooled to 4 K levels by a cryogenic system with a two-stage Stirling cooler, a Joule-Thomson (JT) cycle cooler and a cryostat composed of three stages. Two-stage Stirling cooler precools the JT circuit and also cools radiation shields in the cryostat. JT circuit has three tube-in-tube type heat exchangers and an orifice for JT expansion in the cryostat. The cryogenic system is built, tested and delivered.