Comparison between photoluminescence spectroscopy and photoreflectance spectroscopy in CuGaSe2 epilayer

Photoluminescence （PL） spectroscopy and photoreflectance （PR） spectroscopy are very useful techniques for studying the properties of materials. In this paper, the same material of Cu-rich metal-organic vapour phase epitaxy （MOVPE） grown CuGaSe2 layer is investigated in a temperature range from 20 to 300 K to compare these two techniques. Both PL and PR spectra appear red shifted, less intense and broadened. The temperature dependence of interband transitions is studied by using the Manoogian Leclerc equation. The values of the band gap energy at T=0K and the effective phonon temperature are estimated. The temperature dependences of intensities and broadenings of PL and PR spectral lines are also analysed. Based on the results of the comparison, the features and applications of the PL and PR can be shown in detail.     

啤酒酵母中β-(1-3)葡聚糖的提取及其性能分析

本文采用Sevage脱蛋白法、酸溶液浸提法、碱溶液浸提法对啤酒废酵母细胞壁中的β-(1-3)葡聚糖作了提取试验,并对所获多糖进行生化特性分析,阐述了碱溶液浸提法是从啤酒酵母中回收高质量β-(1-3)葡聚糖的理想途径．     

色散耦合道光学模型对28Si的核子散射数据分析

在光学势中引入色散关系, 相比于通常的耦合道光学模型, 极大地减少了光学势 参数的个数. 采用基于软旋转子模型的耦合道方法对较轻形变核²⁸Si核的中子和质子散射实验数据进行了计算分析, 拟合得到一组色散光学势参数. 计算的中子总截面、以及中子、质子的弹性与非弹性散射微分截面与实验数据有较好的符合.     

基于新型三环谐振器的诱导透明效应分析

针对谐振式微腔的应用需求, 提出了一种新型三环谐振式微腔结构, 类似于原子系统中的电磁诱导透明, 耦合诱导透明(CRIT)效应在一个新的光学微腔系统中已被实验证明. 该结构在硅基上由三个尺寸完全一样的微环腔组成, 通过理论分析、制备和实验测试, 能够观察到CRIT现象, 其频谱具有低群速的狭窄透明峰, 与光栅耦合器的耦合效率为34%, 并且谐振器的品质因数达到了0.65×10⁵, 同时, 失谐的谐振波长可以通过温度变化来控制, 这在旋转传感、光滤波器、光存储器等方面的应用有重要意义.     

液相色谱串联质谱法测定蔬菜中四聚乙醛残留量

建立了测定蔬菜中四聚乙醛残留量的液相色谱串联质谱方法.蔬菜样品经乙腈提取,盐析后吹干乙腈提取液,再用氟罗里硅土固相萃取小柱净化,用正已烷/丙酮(80:20,V/V)混合溶剂洗脱,氮吹后用乙腈-20mmol/L,乙酸铵溶液(70:30,V/V)溶解后进行仪器分析.分析采用XBridgeTM C18色谱柱分离,乙腈-20m...     

Investigations on PMMA-PVdF polymer blend electrolyte with esters of dibenzoic acids as plasticizers

Plasticizers can be used to change the electrical and mechanical properties of polymer electrolytes by reducing the degree of crystallinity and lowering the glass transition temperature. The transport properties of gel type ionic conducting membranes consisting of poly (methyl methacrylate) (PMMA), poly (vinylidene fluriode) (PVdF), Lithium perchlorate (LiClO₄) and dioctyl phthalate (DOP), dibutyl phthalate (DBP), dimethyl phthalate (DMP) or diethyl phthalate (DEP) were studied. The polymer films were characterized by X-ray diffraction, Thermal, Fourier transform infrared and impedance spectroscopic studies. It is found that the addition of DMP as the plasticizer in the PMMA / PVdF-LiClO₄ polymer complex favours an enhancement in ionic conductivity. The temperature dependence of the conductivity of the polymer films seems to obey the VTF relation. The conductivity values are presented and the results are discussed.     

Enolic Schiff Base Zinc Amide Complexes: Highly Active Catalysts for Ring-Opening Polymerization of Lactide and ε-Caprolactone

A series of zinc silylamido complexes based upon NNO tridentate enolic Schiff base framework have been synthesized and characterized. These complexes were tested for the ring opening polymerization of lactide and ε-caprolactone, exhibiting notably high activity at ambient temperature. The influence of imine bridge length and substituents of diketone over the course of polymerization was investigated in details. Remarkably, 4 a was confirmed to be a rare example of exceedingly active and robust zinc catalysts, achieving major transformation of lactide under extremely low loading(0.025 mol%) within 18 min. The influence of various monomers as well as the polymerization mechanism have also been discussed.     

Supramolecular Polymerization Driven by the Dimerization of Single-stranded Helix to Double-stranded Helix

We reported a type of strong and highly directional non-covalent interactions based on the dimerization of single-stranded helix to double-stranded helix that can achieve supramolecular polymerization,giving rise to the formation of linear supramolecular polymers.     

水溶液中环氧值的测定

基于用酸滴定法滴定与亚硫酸钠在水溶液中反应所生成的氢氧化钠,提出了测定环氧值的方法.以环氧氯丙烷(ECH)为试验对象,令一定量的ECH与亚硫酸钠在一定体积的水溶液中反应1～2 h后,分取部分经定容至一定体积的反应溶液,用标准盐酸溶液滴定.按文中给出的公式计算其环氧值,对反应时间、反应温度和溶液的pH值对测定的影响作了试验.方法的检出限为4.5×10-5mol·L-1,还对方法的精密度和回收率进行了试验,测得相对标准偏差和回收率依次在1.3%～1.8%之间和95.9%～98.6%之间.     

铕(Ⅲ)、铽(Ⅲ) β-二酮配合物的制备及表征

醋酸铕、醋酸铽分别与乙酰丙酮在60°C水浴下加热回流,生成两种稀土β-二酮配合物,即乙酰丙酮铕(Eu(acac)3?3H2O)和乙酰丙酮铽(Tb(acac)3?3H2O),在紫外灯下观察配合物发光现象,乙酰丙酮铕在紫外灯下显暗红色,乙酰丙酮铽在紫外灯下显亮绿色。红外分析结果与理论相吻合,荧光分析表明它们是较好的荧光材料,热分析结果说明它们的热稳定性相对较高。