分子模拟在高性能聚合物纤维力学性能研究中应用

聚合物力学性能取决于单个分子链的力学性质和分子链聚集形态。综述了通过分子模拟研究高度取向的液晶高分子纤维的微观力学行为,从微观角度揭示聚合物力学性能的本质,解释其力学破坏的结构因素。     

基于FDTD算法研究超短脉冲与二能级原子系统的相互作用

以往对于超短脉冲与二能级原子系统的研究大多基于一些近似方法(慢变包络近似和旋转波近似等),从而求得解析的近似解。但是,由于忽略掉一些有用的光场中的信息,就会造成光场导数项所产生的非线性性质的缺失。本文基于FDTD算法和预测-校正法相结合,建立了预测-校正FDTD算法,用于研究超短脉冲与二能级原子系统的相互作用,以准确地描述光场与原子系统相互作用的特征,验证了面积定理的部分规律;进一步构建了能够实现完全反转原子系统上下能级粒子的短脉冲。相关研究可为目标的特征分析提供参考。     

From Claringbullite to a New Spin Liquid Candidate Cu_3Zn(OH)_6FCl

The search for quantum spin liquid(QSL) materials has attracted significant attention in the field of condensed matter physics in recent years, however so far only a handful of them are considered as candidates hosting QSL ground state. Owning to their geometrically frustrated structures, Kagome materials are ideal systems to realize QSL. We synthesize the kagome structured material claringbullite(Cu_4(OH)_6FCl) and then replace inter-layer Cu with Zn to form Cu_3Zn(OH)_6FCl. Comprehensive measurements reveal that doping Zn~(2+) ions transforms magnetically ordered Cu_4(OH)_6FCl into a non-magnetic QSL candidate Cu_3Zn(OH)_6FCl. Therefore,the successful syntheses of Cu_4(OH)_6FCl and Cu_3Zn(OH)_6FCl provide not only a new platform for the study of QSL but also a novel pathway of investigating the transition between QSL and magnetically ordered systems.     

新高考改革背景下大学与中学物理实验有效衔接的研究

分析了在新高考背景下大学物理实验与中学物理实验衔接存在问题的原因,结合调查情况,提出了二者之间在沟通交流、课程设置、教学内容及教学方法方面的改革措施,实现大学与中学物理实验的有效衔接。     

HL-2A托卡马克超声分子束注入深度和加料效果研究

超声分子束注入深度与加料效率是分子束加料研究中的基本课题.在近期开展的超声分子束注入实验中，发现分子束注入深度与等离子体电子温度和密度、分子束源的气压和温度有直接关系，获得了分子束注入深度的定标律.在低温气体源(液氮冷却)的分子束注入实验中，发现分子束流中形成了团簇，其注入深度超过30 cm，分析了在低温气源分子束注入实验中的团簇现象. 关键词： 超声分子束注入 注入深度 加料效率 团簇     

Resonance in Defect Turbulence under Periodic External Force

The periodically forced spatially extended Brusselator is investigated in the chaotic regime. We explore resonant or non-resonant patterns generated under various forcing frequencies and forcing amplitudes. Resonant spatially uniform oscillation and irregular structures are found. Furthermore two types of regular spatial patterns are generated under appropriate parameters. Our results of numerical simulations demonstrate that periodic force can give rise to resonant patterns in forced systems of spatiotemporal chaos similar to the situation of forced systems of regular oscillations.     

Spectroscopic investigation of a new crystal： Nd^3＋,Yb^3＋：YVO4

The absorption and emission spectra of the YVO4 single crystal co-doped with 1 at.% Nd^3＋ and 1 at.% Yb^3＋ are investigated. The efficient Nd^3＋ → Yb^3＋ energy transfer and the back transfer （Yb^3＋ → Nd^3＋） are observed at room temperature. The fluorescence lifetime of the 4F3/2 level of Nd^3＋ in Nd,Yb：YVO4 is measured under 808 nm laser light excitation. The efficiency of Nd^3＋ → Yb^3＋ energy transfer in YVO4 is determined to be about 34%.     

Observation of Non-Local Transport Phenomena with SMBI in HL-2A

The non-local transport phenomenon induced by supersonic molecular beam injection （SMBI） was first observed in the HL-2A tokomak. In comparison with the phenomena induced by other methods in various tokamaks, it has its own feature： the effect induced by SMBI in HL-2A lasts much longer than that induced by pellet injection in other similar size tokomaks. Both the bolometer radiation and He emission decrease when the non-local effect appears. This suggests that an electron transport barrier has been formed at the position just outside the q = 1 surface when the non-local effect appears.     

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用中平面往复快速扫描6探针组观测HL-2A装置边缘等离子体的扰动特性。在一次放电中能测量到边缘等离子体参数的时空分布及其涨落量，雷诺胁强与极向流和带状流的关系，以及静电涨落驱动的粒子通量和热通量的径向变化。在多发弹丸注入(MPI)和多脉冲超声分子束注入(SMBI)条件下，研究了边缘参数的涨落和相关特性。实验结果表明：SMBI和MPI等注入手段改变了边缘的扰动特性；雷诺胁强的径向梯度可以驱动带状流，抑制湍流输运。