Polymorphism and solvates of 3,3'‐dihydroxy‐ß,ß‐carotene‐4,4'‐dione: Screening and their thermodynamics

3,3'‐dihydroxy‐ß,ß‐carotene‐4,4'‐dione (DCD) is a carotenoid used for the pink coloration in animal and fish foods. Two nonsolvated and two solvated forms of this compound have been discovered and characterized using different analytical techniques. The thermodynamic stability of the relevant polymorphs is revealed. The transformation rate depends strongly on the selection of solvent medium. Moreover, different chemical stability refers to the shelf life is studied correlating to the different polymorphs. The results show the possibilities to improve the pigmentation efficiency and chemical stability by a changing in the crystal polymorphs. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

A2( MoO4)3(A=Al,Cr,Fe)结构与相变的Raman光谱研究

用XRD、Raman光谱和DSC研究了Al2 (MoO4)3、Cr2( MoO4)3和Fe2 (MoO4)3的结构与相变.Al2(MoO4)3、Cr2 (MoO4)3和Fe2 (MoO4)3在室温下为单斜相,分别在483 K、673 K和783 K附近转变为正交相.发现MO4四面体的对称和反对称伸缩振动模的频率和相对强...     

快速烧结合成Zr1-xMxW2O8(M=Hf,Sn,Y)固溶体的Raman光谱研究

首次采用快速烧结合成技术制备了Zr1-xMxW2O8 (M=Hf,Sn,Y)系列固溶体.制备的合适条件为:温度1523～1553 K,时间30 min～1 h,同传统固相反应烧结相比,该方法合成时间和能耗显著降低.XRD和Raman光谱分析表明,Zr1-xMxW2O8 (M=Hf,Sn,Y)固溶体具有α-ZrW2O8的...     

不良导体导热系数与温度关系研究

采用稳态平板法测量不良导体的导热系数时,关键是得到稳态时不良导体的传热速率。根据稳态时传热速率与散热铝盘的散热速率相等,可以测定自然冷却过程中,稳态时散热铝盘温度T2所对应的冷却速率。基于Matlab软件,分析并绘制曲线直观反映出温度、时间、冷却速率三者之间的关系,用拟合法研究了不良导体导热系数随温度变化的关系。     

带孔片状不良导体导热系数测试方法探究

推导出稳态法测量带孔片状不良导体导热系数的适用公式,并采用有效的方法对光盘进行了测试分析.     

The effects of induced heat loads on the propagation of Ince-Gaussian beams

Thermal effects are very much influential in high power beam generators. Their impacts on special types of beams such as Helmholtz-Gauss beams have attracted special attentions. This work reports thermal effects on the generation and propagation of Ince-Gaussian beams. The results show considerable beam spot size variations for near fields under various induced heat loads. As Ince-Gaussian beams are directly related to cavity symmetry breaking, the results can greatly help system designers for circumventing these types of symmetry breaks usually encountered in high power lasers.     

Propagation of coupled dipole-mode beams in nonlocal thermal media

The mutual trapping of two dipole-mode beams is investigated numerically in nonlocal thermal media. Results show that the incoherent attraction of perpendicularly aligned dipole-mode beams can enhance the stability of their composite structure. When the powers of the dipole components are identical, the larger the power, the shorter the stable distance. While when the powers are different, the closer the powers, and the longer the stable distance. Furthermore numerical results proved that the coupled solitary structures exhibit stable propagation for much larger distances than the corresponding scalar cases.     

气源MBE外延自组装GeSi量子点的光致荧光

利用气源分子束外延技术(MBE)制作了GeSi自组装量子点样品.利用原子力显微镜(AFM)和光致荧光(PL)光谱研究了该量子点的形貌和光学性质.气源MBE在较低温度下生长的量子点材料具有较高的量子点覆盖度.200K以下载流子以局域激子形式束缚在量子点中,激子束缚能约为17 meV.升温至200 K,载流子的输运过程发生...     

快速热退火对Co/Si0.85Geo.15肖特基结电学特性的影响

用离子束溅射技术分别在SiO2和单晶Si衬底上沉积了Si1-xGex和Co薄膜.在不同温度下,对Co/Si1-xGex肖特基结进行快速热退火处理(RTA),对处理后的样品进行了表面形貌和电学测量.发现退火温度升高,样品表面粗糙度变大,理想因子也变大,但对肖特基势垒高度(SBH)的影响很小.分析认为,随着退火温度的升高,...     

聚合物发光二极管面光源的光热特性

运用传输矩阵法及MATLAB软件模拟计算了以MEH-PPV为发光材料的PLED面光源出光率,分析了发光层、PEDOT层、ITO层对器件出光率的影响.模拟分析了玻璃表面半球形、圆台形、圆锥形3种微形貌对器件出光率的影响.仿真结果表明,玻璃表面为圆锥形微散射层对提高器件出光率最有利,且出光均匀性最好.最后分析了PLED面光...