ICP-AES测定夜交藤中金属元素的含量

以干热法处理夜交藤样品,用电感耦合等离子体-原子发射光谱仪检测夜交藤中Cu、Zn、Fe、Mn、Pb、Cd、Al、V、Ti的含量。结果表明,Fe和Al含量较高,其他含量较低,含量测定相对标准偏差在0.53%—3.3%之间,加标回收率在85.1%—105.0%之间,干热法处理样品和ICP-AES相结合的方法能够较好地分析夜交藤中的金属离子含量。     

表面热透镜薄膜吸收测量灵敏度提高方法

为提高表面热透镜薄膜吸收测量仪的灵敏度，在表面热透镜衍射理论基础上，通过数值模拟给出了探测激光腰斑半径、探测激光腰斑到样品表面距离、样品到探测光纤端面距离等仪器参数的优化方法. 经优化调整后该仪器能达到优于0.1ppm量级的薄膜吸收率测量灵敏度. 关键词： 吸收测量 表面热透镜 光热形变 薄膜     

不同波长激光激发下C6H12受激拉曼散射模式竞争

发现不同波长激光激发下C6H12的受激拉曼散射模式竞争现象. 在不同波长的激光激发下,不同拉曼模式的Stokes光占优势. 短波长(404,532 nm)激光激发时小频移模式ω1(802 cm-1)为弱增益模式,大频移模式ω2(2852-3038 cm-1)为强增益模, 主要产生ω2模式的Stokes光. 长波长(808 nm)激光激发时,小频移模式ω1为强增益模式,大频移模式ω2为弱增益模式,有利于ω1模式Stokes光输出. 在普通激光拉曼光谱实验中观察到类似现象. 讨论了这一现象的产生机理及应用前景.     

Synthesis, structure, and magnetic properties of three 1D chain complexes based on high-spin metal-cyanide clusters: [Mn(III)6M(III)] (M = Cr, Fe, Co)

On the basis of high-spin metal-cyanide clusters of Mn(III)(6)M(III) (M = Cr, Fe, Co), three one-dimensional (1D) chain complexes, [Mn(salen)](6)[Cr(CN)(6)](2)·6CH(3)OH·H(2)O (1), [Mn(5-CH(3))salen)](6)[Fe(CN)(6)](2)·2CH(3)CN·10H(2)O (2), and [Mn(5-CH(3))salen)](6)[Co(CN)(6)](2)·2CH(3)CN·10H(2)O (3) [salen = N,N'-ethylenebis(salicylideneiminato) dianion], have been synthesized and characterized structurally as well as magnetically. Complexes 2 and 3 are isomorphic but slightly different from complex 1. All three complexes contain a 1D chain structure which is comprised of alternating high-spin metal-cyanide clusters of [Mn(6)M](3+) and a bridging group [M(CN)(6)](3-) in the trans mode. Furthermore, the three complexes all exhibit extended 3D supramolecular networks originating from short intermolecular contacts. Magnetic investigation indicates that the coupling mechanisms are intrachain antiferromagnetic interactions for 1 and ferromagnetic interactions for 2, respectively. Complex 3 is a magnetic dilute system due to the diamagnetic nature of Co(III). Further magnetic investigations show that complexes 1 and 2 are dominated by the 3D antiferromagnetic ordering with T(N) = 7.2 K for 1 and 9.5 K for 2. It is worth noting that the weak frequency-dependent phenomenon of AC susceptibilities was observed in the low-temperature region in both 1 and 2, suggesting the presence of slow magnetic relaxations.     

A CVD diamond film detector for pulsed proton detection

A chemical vapour deposition （CVD） diamond film detector was prepared and the main characteristics for pulsed proton detection were studied at Beijing Tandem Accelerator. The result shows that the charge collection efficiency of the detector increases with increasing electric field intensity and reaches to 9.44% at 5 V/μm with the charge collection distance of 15.9 μm. The relationship between the sensitivity of the detector and proton energy is consistent with the Monte Carlo （MC） simulation result. Its plasma time for a pulse with 4.85×10^5 protons is 1l.2ns. The dose threshold for onset of damage under 9MeV proton irradiation in the detector is about 10^13 cm^-2. All of the results show that a CVD diamond detector has fast time response and high radiation hardness, and can be used in pulsed proton detection.     

聚(偏氟乙烯-三氟乙烯)纳米薄膜极化反转与疲劳特性

采用旋涂法制备了厚度为140 nm的聚(偏氟乙烯-三氟乙烯)[P(VDF-TrFE)]纳米薄膜, 研究了不同退火温度以及环境相对湿度对薄膜的极化反转和疲劳性能的影响. 运用X射线衍射仪、扫描电子显微镜和傅里叶变换红外光谱仪等测试技术对薄膜的微结构进行了表征. 实验结果表明, 通过不同温度的退火处理, P(VDF-TrFE)铁电薄膜的结晶度随着退火温度的升高而不断提高, 并且一定的温度范围内的退火处理可以提高薄膜的极化性能; 此外, P(VDF-TrFE) 铁电薄膜性能还表现出一定的环境湿度的敏感特性, 这与薄膜的物理性能和结构特点密切相关; P(VDF-TrFE)铁电薄膜在不同的环境湿度条件下 表现出较好的电学特性, 其漏电流均保持在10 ^-7A/cm² 的较低水平. 本工作揭示了再退火过程对薄膜的极化反转速度和疲劳恢复特性的影响, 并结合薄膜二次疲劳结果, 探讨了薄膜可逆的内部疲劳恢复特性机理.     

Facile synthesis of nitrogen-doped graphene aerogels functionalized with chitosan for supercapacitors with excellent electrochemical performance

Three-dimensional porous nitrogen-doped graphene aerogels (NGAs) were synthesized by using graphene oxide (GO) and chitosan via a self-assembly process by a rapid method. The morphology and structure of the as-prepared aerogels were characterized. The results showed that NGAs possesed the hierarchical pores with the wide size distribution ranging from mesopores to macropores. The NGAs carbonized at different temperature all showed excellent electrochemical performance in 6 mol/L KOH electrolyte and the electrochemical performance of the NGA-900 was the best. When working as a supercapacitor electrode, NGA-900 exhibited a high specific capacitance (244.4 F/g at a current density of 0.2 A/g), superior rate capability (51.0% capacity retention) and excellent cycling life (96.2% capacitance retained after 5000 cycles).     

含席夫碱基的螺吡喃双功能光致变色材料的合成及性质

设计合成了一系列含席夫碱基的螺吡喃双功能光致变色材料4a~4n. 通过1H NMR, IR和HRMS对其结构进行了表征. 研究了化合物在几种溶剂和PMMA膜中的光致变色性质, 研究了化合物4a在甲醇中, 以及化合物4a和4f在高分子介质聚甲基丙烯酸甲酯(PMMA)中的消色过程. 结果表明, 化合物4e在PMMA膜中光照后呈现出与其它化合物不同的颜色, 为罕见的绿色. 化合物4a在二氯甲烷溶液中有良好的荧光性能. 所合成的新型含席夫碱基的螺吡喃双功能光致变色材料在甲醇、二氯甲烷和环己烷溶液中及在PMMA膜中均表现出良好的光致变色性质.     

小波变换用于示波信号中有用信息提取的研究

示波分析是近年来在我国发展起来的一个新的电化学分析研究领域［１～４］．它根据阴极射线示波器荧光屏上示波图及其变化进行分析测试,从原理上可以将其分为示波电位法和示波计时电位法;从测定方式上可以将其分为示波滴定和示波测定．关于示波电位法的一些理论问题（如...     

新型含氧亚甲基和亚胺桥键的液晶化合物的合成及介晶性

报道一类新的、结构通式为MeO₂CC₆H₄CH₂OC₆H₄CH＝NC₆H₄Y, Y＝OC_nH_2n＋1, Me, Cl, Br, NO₂, H 的棒状液晶化合物的合成. 通过DSC和偏光显微镜对其介晶性研究发现, 除Y＝H外, 这些化合物均具有介晶性. 当Y为非烷氧基时, 呈向列相液晶; 当Y为较短的烷氧基时(n＝1～3), 液晶化合物具有向列相(N); Y为较长烷氧基时(n＝4～16 ), 液晶化合物只有近晶B相(S_B)和近晶A相(S_A); S_A-I相变的熵变随烷氧链原子数而奇-偶变化, 但与N-I相变的“奇-偶效应”相反.