烷基和酰基钴化合物合成方法研究进展

总结了烷基和酰基钴化合物及其膦配体衍生物的合成方法,综述了其合成方法研究进展.指出烷基和酰基钴化合物是多种重要催化反应如氢甲酰化反应、甲醇同系化反应、酰胺羰基化反应的循环中间体;近年来,烷基和酰基钴化合物因可以催化羰基化聚合反应而引起了广泛的关注.     

高效液相色谱法检测化妆品中着色剂罗丹明B、金光红C和颜料红57

采用N,N-二甲基甲酰胺提取样品中的待测物,建立了化妆品中禁、限用着色剂罗丹明B、颜料红57和金光红c的高效液相色谱检测方法。以XDB-C18柱为分析柱,5mmol／L四丁基氢氧化铵-氢氧化钾水溶液（磷酸调至pH7．00）和甲醇为流动相,梯度洗脱。550am（罗丹明B）和480nm（颜料红57和金光红C）为检测波长,柱温30℃,流速1．0mL／min,保留时间定性,外标法定量。结果表明在0．25-20mg／L（罗丹明B和金光红C）、0．5-40mg／L（颜料红57）浓度范围内线性关系良好,检出限分别为5,20,20mg／kg（S／N=10）,实际样品中的加标回收率分别为94．8％～100．5％,95．1％～103．1％,82．5％-90．5％,相对标准偏差为0．9％～4．6％。该方法前处理简单、易操作,检测结果准确可靠。能够满足化妆品中这3种着色剂的检测要求和监管需要。     

NaGdF4:Eu3+的结构和VUV荧光性质

利用水热方法合成了纯度较高的六方结构的ＮaGdF4,在氧气存在条件下950℃加热处理可以使其转变为CaF2型立方结构,在真空紫外光激发下,六方结构的NaGdF4:Eu^3 中的Gd^3 离子吸收一个光子,并将能量分两步传递给Eu^3 离子,发生双光子发射,立方结构的NaGdF4:Eu^3 中存在有一定量的氧离子取代缺陷,使Gd^3 离子4f-5d跃迁移到177nm附近,这与惰性气体放电产生的真空紫外波长一致。     

用规整膜板对砷化镓的三维微结构图形加工刻蚀

以微齿轮图形结构作为规整模板 ,用约束刻蚀剂层技术对GaAs样品表面进行了加工刻蚀 .在有捕捉剂H3AsO3存在的情况下 ,规则微齿轮图形能够很好地在样品表面复制 .刻蚀结果与没有捕捉剂存在时的刻蚀结果做了比较 .另外还测试了不同方法制得膜板的性能 ,初步探讨了电化学模板的制作工艺 .     

烧结温度对红色长余辉发光材料Ca0.8Zno.2TiO3∶ Pr3+,Na+性能的影响

采用溶胶凝胶燃烧法合成了Ca0.8Zn0.2TiO3∶Pr3+,Na+纳米红色长余辉发光材料,利用XRD、SEM、荧光分光光度计、热释光谱仪和照度计研究了烧结温度对样品物相、形貌以及发光性能的影响.结果表明:煅烧温度为600℃时生成了CaTiO3相,当烧结温度大于700℃时,出现了Zn2TiO4相;随煅烧温度的升高,样品的晶粒逐渐变大,平均晶粒尺寸均小于100nm;不同温度下样品的激发峰位于328nm,发射峰位于613 nm,归属于P,+的1D2-3 H4跃迁;当烧结温度为800℃时,样品的初始亮度和余辉时间最佳,其分别为2000 mcd/m2和10 min(≥1mcd/m2).     

Electronic Phase Separation in Iron Selenide(Li,Fe)OHFeSe Superconductor System

The phenomenon of phase separation into antiferromagnetic(AFM) and superconducting(SC) or normal-state regions has great implication for the origin of high-temperature(high-T_c) superconductivity. However, the occurrence of an intrinsic antiferromagnetism above the T_c of(Li,Fe)OHFe Se superconductor is questioned. Here we report a systematic study on a series of(Li,Fe)OHFe Se single crystal samples with T_c up to ～41 K. We observe an evident drop in the static magnetization at T_(afm) ～ 125 K, in some of the SC(T_c 38 K, cell parameter c■9.27 ?) and non-SC samples. We verify that this AFM signal is intrinsic to(Li,Fe)OHFe Se. Thus, our observations indicate mesoscopic-to-macroscopic coexistence of an AFM state with the normal(below T_(afm)) or SC(below T_c) state in(Li,Fe)OHFe Se. We explain such coexistence by electronic phase separation, similar to that in high-T_c cuprates and iron arsenides. However, such an AFM signal can be absent in some other samples of(Li,Fe)OHFe Se, particularly it is never observed in the SC samples of T_c 38 K, owing to a spatial scale of the phase separation too small for the macroscopic magnetic probe. For this case, we propose a microscopic electronic phase separation. The occurrence of two-dimensional AFM spin fluctuations below nearly the same temperature as T_(afm), reported previously for a(Li,Fe)OHFe Se(T_c ～ 42 K) single crystal, suggests that the microscopic static phase separation reaches vanishing point in high T_c(Li,Fe)OHFe Se. A complete phase diagram is thus established. Our study provides key information of the underlying physics for high-T_c superconductivity.     

原子力显微镜与表面形貌观察

简要介绍原子力显微镜观察材料表面形貌的原理。运用原子力显微镜,观察CD,VCD,DVD和可擦写的VCD光盘的刻录划痕,分析各类光盘的刻录特征,指出原子力显微镜在观察材料表面微米至纳米尺度形貌是非常有效的。     

钚气溶胶环境中惰性气体氪迁移过程研究

放射性气体的安全性问题是涉及反应堆运行中必需研究的重要问题.因此在钚气溶胶环境中,对钚材料裂变产生的放射性气体裂变产物,需要研究其在钚气溶胶环境中的迁移过程.对放射性惰性气体Kr87,Kr88的实验测量数据进行了具体分析.依据它们具有钚材料直接裂变和作为固体裂变产物子体两种来源这一物理特性,在不同的制样时间对Kr87/Kr88比值变化规律进行分析.确立了这两种来源的在钚气溶胶环境中的物理图像和迁移过程的物理模型,并与实验数据进行比较以验证模型的正确性. 关键词： 钚气溶胶 气体裂变产物 放射性Kr87/Kr88 迁移过程     

Noncontinuous Solitary Wave Solutions for Double sine-Gordon Equation

Using the tanh method and a variable separated ordinary difference equation method to solve the double sineGordon equation, we derive some new exact travelling wave solutions, especially a new type of noncontinuous solitary wave solutions. These noncontinuous solitary wave solutions are verified by using the conservation law theory.     

Magnetic field effect in photodetachment from negative ion in electric field near metal surface

Based on the closed-orbit theory, the magnetic field effect in the photodetachment of negative ion in the electric field near a metal surface is studied for the first time. The results show that the magnetic field can produce a significant effect on the photodetachment of negative ion near a metal surface. Besides the closed orbits previously found by Du et al. for the H in the electric field near a metal surface (J. Phys. B 43 035002 (2010)), some additional closed orbits are produced due to the effect of magnetic field. For a given ion-surface distance and an electric field strength, the cross section depends sensitively on the magnetic field strength. As the magnetic field strength is very small, its influence can be neglected. With the increase of the magnetic field strength, the number of the closed orbits increases greatly and the oscillation in the cross section becomes much more complex. Therefore we can control the photodetachment cross section of the negative ion by changing the magnetic field strength. We hope that our results may guide future experimental studies for the photodetachment process of negative ion in the presence of external fields and surfaces.