香兰素对甲苯胺希夫碱稀土配合物的红外光声光谱

研究了香兰素对甲苯胺希夫碱及其金属配合物在３８００－２００ ｃｍ＾－１范围的傅里叶变换红外光谱光谱，对主要谱带进行了经验归属。     

活血逐瘀颗粒剂中芍药甙的含量测定

本文采用了薄层色谱法将复方制剂活血逐瘀颗粒中的芍药甙与其他成分分离，用紫外分光光度法测定芍药甙的含量，其平均回收率为９８．７４％，变异系数为１．４３％，本文方法抗干扰能力强，适合于中药复方制剂中芍药甙的定量分析。     

Electric-pulse-induced local conducting area and joule heating effect in VO2/Al2O3 films

We investigated the effect of an electric-pulse on the insulator–metal phase transition of VO₂/Al₂O₃ films using synchrotron-based infrared microspectroscopy. By monitoring the time-resolved optical response, we could demonstrate that local conducting areas are formed under the influence of the electric-pulse, and the Joule heat generated from the local current flow drives a consecutive thermal phase transition in the adjacent sample area.     

Low-field magnetoresistance of Ag-substituted perovskite-type manganites

A series of bulk polycrystalline Nd_1−xAg_xMnO₃ samples were prepared by conventional solid-state reaction processing, for x between 0.1 and 0.5. The structure, magnetism, and magnetoresistance (MR) of the samples are investigated. The X-ray diffraction patterns show that the x=0.1 sample is a single perovskite structure, while x0.167, samples consist of a ferromagnetic perovskite phase and two nonmagnetic phases, Ag and Mn₃O₄. The MR of Nd_1−xAg_xMnO₃ is enhanced by increasing the composition of Ag. Compared with the sample of x=0.1, the x=0.5 sample has a significantly larger value of low-field MR. The enhanced low-field MR is related to the spin-dependent scattering of spin-polarized electrons at the interfaces between the perovskite grains and silver granules.     

Analytical expression for the diffraction field of an axicon using the ray-tracing and interference method

We present a simple analytical expression for calculating the vector field distribution behind an axicon using the ray tracing and interference method. This expression can be used for analyzing vector beam propagation throughout the whole space behind the axicon, with any base angle. Using the present analytical expression, we have studied the propagation characteristics of the four kinds of polarizations, linear polarization, left-handed circular polarization (i.e., the radial polarization), right-handed circular polarization, and azimuthal polarization, incident on the axicon. We found that the longitudinally-polarized component has to be considered for a large base angle and high refractive index of axicons, apart from the azimuthally-polarized beam of incidence. PACS 42.15.Dp; 42.60.Jf; 42.25.Hz     

Synthesis of tungsten carbide nanopowder via submerged discharge method

Tungsten carbide nanopowder was prepared via pulsed discharge of bulk tungsten and graphite rods immersed in pure ethanol. The effect of discharge parameters on the characteristics of final products was investigated. Structural and morphological characterization of nanopowder was performed by means of X-ray diffraction analysis and transmission electron microscopy. In order to determine the feasibility of using synthesized material as an electrocatalyst, tungsten carbide nanopowder was tested for hydrogen evolution. A correlation was found between morphology of nanoparticles, their phase composition and electrocatalytic activity.     

Room-temperature cw and pulsed operation of a diode-end-pumped Tm:YAP laser

We report the continuous-wave and acousto-optical Q-switched operation of a diode-end-pumped Tm:YAP laser. Continuous-wave output power of 3.5 W at 1.99 μm was obtained under the absorbed pump power of 14 W. Under Q-switched laser operation, the average output power increased from 1.57 W to 2.0 W, with an absorbed pump power of 12.6 W, as the repetition rate increased from 1 kHz to 10 kHz. The maximum Q-switched pulse energy was 1.57 mJ with a repetition rate of 1 kHz. The minimum pulse width was measured to be about 80 ns, corresponding to a peak power of 19.6 kW. PACS 42.55.Rz; 42.55.Xi; 42.60.Gd     

Optical characterization of sol gel TiO<Subscript>2</Subscript> monoliths doped with Brilliant Green

Amorphous titanium dioxide monoliths doped with brilliant green (BG) were synthesized by the sol-gel process. The optical properties of the monoliths were characterized by Photoacoustic Spectroscopy and Photoluminescence Spectroscopy. The absorption spectra for the BG-doped TiO₂ monoliths exhibited two well defined absorption regions: a band below 400 nm corresponding to TiO₂ absorption and three absorption bands centered at 424 nm, 588 nm, and 632 nm due to brilliant green. While the undoped TiO₂ monoliths showed no luminescence, the doped samples showed a strong luminescence band at 673 nm, which increased its intensity for increasing organic dye doping.     

Structure and electrical characterization of amorphous ErSiO films deposited by rf magnetron sputtering on Si (001)

Amorphous ErSiO films have been fabricated on p-type Si (001) substrates using rf magnetron sputtering technique. X-ray diffraction, high-resolution transmission electron microscopy, and atomic force microscopy were employed to investigate the samples. It is found that ErSiO film exhibits a flat surface, a sharp interface and superior electrical properties after post-deposition annealing in O₂ ambience for 30 min at 450°C. The effective dielectric constant of the film is measured to be 14.2, and the effective oxide thickness reaches 1.9 nm, with a low leakage current density of 1.1×10⁻⁴ A/cm² at an electric field of 1 MV cm⁻¹ after annealing at 450°C. The obtained characteristics make the amorphous ErSiO films a promising substitute for SiO₂ as a high-k gate dielectric.     

Efficient continuous-wave 908 nm Nd:YLF laser emission under direct 880 nm pumping

The quasi-three-level 908-nm continuous-wave laser emission under direct diode laser pumping at 880 nm into emitting level ⁴ F _3/2 of Nd:YLF have been demonstrated. An end-pumped Nd:YLF crystal yielded 4.7 W of output power for 11.8 W of absorbed pump power. The slope efficiency with respect to the absorbed pump power was 43.3%. Comparative results obtained for the pump with diode laser at 808 nm, into the highly-absorbing ⁴ F _5/2 level, are given in order to prove the advantages of the 880-nm wavelength pumping.