Carbon Encapsulation of High Entropy Alloy Nanoparticles with Extraordinary Coercivity and Saturation at Room Temperature

Owing to their unique properties and technological potential, high entropy alloys (HEAs) have become the subject of great interest in the materials science community. HEAs consist of more than four principle elements in equimolar ratio so their configurational entropy is intrinsically greater than one-principle element based. The increasing surface energy and chemical tendency toward clustering of like atoms at low dimension, however, make production of HEA-nanoparticles (HEA-NPs) extremely difficult. A facile production of HEA-NPs inside carbon nanotubes and nanoparticles is demonstrated in this work. Electron microscopic and elemental analyses confirm encapsulated to be solution phase; some embrace carbides and form multidomains with chemical composition ranging from quaternary to quinary phase. Multidomains and nonmagnetic centers create hardening thus promoting coercivity significantly at room temperature. Alloying induces electron redistribution into high spin states, accounting for observed high saturation. Configurational entropy of encapsulated HEA-NPs lies on a range comparable with bulk.     

Towards the meV limit of the effective neutrino mass in neutrinoless double-beta decays

We emphasize that it is extremely important for future neutrinoless double-beta(0νββ)decay experiments to reach the sensitivity to the effective neutrino mass|mββ|≈1 meV.With such a sensitivity,it is highly possible to discover the signals of 0νββ decays.If no signal is observed at this sensitivity level,then either neutrinos are Dirac particles or stringent constraints can be placed on their Majorana masses.In this paper,assuming the sensitivity of|mββ|≈1 meV for future 0νββ decay experiments and the precisions on neutrion oscillation parameters after the JUNO experiment,we fully explore the constrained regions of the lightest neutrino mass m1 and two Majorana-type CP-violating phases{ρ,σ}.Several important conclusions in the case of normal neutrino mass ordering can be made.First,the lightest neutrino mass is severely constrained to a narrow range m1∈[0.7,8]meV,which together with the precision measurements of neutrino mass-squared differences from oscillation experiments completely determines the neutrino mass spectrum m2∈[8.6,11.7]meV ing phases is limited to ρ∈[130°,230°],which cannot be obtained from any other realistic experiments.Third,the sum of three neutrino masses is found to beΣ≡m1+m2+m3∈[59.2,72.6]meV,while the effective neutrino mass for beta decays turns out to be mβ≡(|Ue1|2m1^2+|Ue2|2m2^2+|Ue3|2m3^2)1/2∈[8.9,12.6]meV.These observations clearly set up the roadmap for future non-oscillation neutrino experiments aiming to solve the fundamental problems in neutrino physics.     

有机化学多媒体教学的一些体会

针对有机化学课程特点,编写了适合课堂教学的有机化学电子教案,总结了有机化学多媒体教学实践的经验,提出了多媒体教学中应当注意的一些问题。     

柱前衍生化高效液相色谱荧光检测法测定桑叶中的1-脱氧野尻霉素

建立了芴甲氧酰氯(FMOC—Cl)柱前荧光衍生一高效液相色谱法测定桑叶中1-脱氧野尻霉素(DNJ)的方法。桑叶经0．05mol／L,盐酸提取,在pH8．5的硼酸盐缓冲溶液条件下,DNJ反应生成荧光产物,然后用高效液相色谱-荧光检测器测定。流动相为乙腈-0．1％醋酸(55：45,V/V)。线性范围为0．567～34mg／L(相关系数r=0．9999);检出限为0．03mg／L。实验测得桑叶中DNJ含量为0．24％;平均回收率为97．1％,RSD为1．35％(n=6)。     

Cr,Fe,Cu/Al2O3界面化学结构的光电子能谱

应用Ｘ－射线光电子能谱，通过离子刻蚀，原位研究第四周期过渡金属与氧化铝所形成界面的化学状态，结果表明，Ｃｒ，Ｆｅ在界面处有不同程度的氧化，氧化程度Ｃｒ＞Ｆｅ，而Ｃｕ则无明显氧化。化学成份的定量分析表明，界面过渡层的厚度与界面化学反应强弱直接相关。     

微波合成SrTiO3的工艺、结构与性能研究

应用微波会成这一材料合成新方法制备SrTiO3，研究了不同工艺条件下微波合成产物的结构，确定出制备纯净SrTiIO。的合成条件．对微波合成的工艺及其影响因素进行详细的探索，从合成产物的显微结构、粒度分布、比表面积、烧结性能等方面比较了微波合成与常规固相合成的差别，结果表明微波合成与各种常规方法相比有合成时间短、合成工艺简单、合成产物性能好等特点，是一种有发展潜力的材料合成技术．     

二(三氟乙酸)氯化钕的合成及其对双烯聚合的催化活性

1976年F.Dawans在研究丁二烯定向聚合时,曾引入三氟乙酸氯化镍类型的乙醚络合物,对聚合机理作了令人满意的解释并已得到实际应用。但迄今为止,稀土催化剂作为定向聚合催化剂,在三烷基铝低用量条件下,均系非均相的三元体系。这在理论研究和实际应用上都存在一定困难。     

Circular patterns of calcium oxalate crystals induced by defective Langmuir-Blodgett film

The injury of the renal epithelial cell membrane can promote the nucleation of nascent crystals, as well as adhesion of crystals on it. It thus accelerates the formation of renal calculi. In this paper, the defective Langmuir-Blodgett (LB) films were used as a model system to simulate the injured renal epithelial cell membrane. The microcosmic structure of the defective LB film and the molecular mechanism of the effect of this film on nucleation, growth, deposited patterns and adhesion of calcium oxalate monohydrate (COM) were investigated. The circular defective domains were formed in dipalmitoylphosphatidylcholine (DPPC) LB film after the film was treated by potassium oxalate. These domains could induce ring-shaped patterns of COM crystals. In comparison, the LB film without pretreatment by potassium oxalate only induced random growth of hexagonal COM crystals. As the crystallization time increased, the size of COM crystals in the patterns increased, the crystal patterns changed from empty circles to solid circles, and the number of the circular patterns with small size (5-20 μm) increased. The results would shed light on the molecular mechanism of urolithiasis induced by injury of the renal epithelial membrane at the molecular and supramolecular level.