Growth and optical properties of Er,Yb:YAl3(BO3)4 crystal

Single crystal of erbium, ytterbium-codoped yttrium aluminum tetraborate Er,Yb:YAl₃(BO₃)₄(Er,Yb:YAB) has been grown by the flux method. The absorption spectrum in the visible and NIR regions of Er,Yb:YAl₃(BO₃)₄ crystal are measured at room temperature and fluorescence spectrum of Er,Yb:YAl₃(BO₃)₄ crystal are also measured at room temperature, excited by 976 nm laser. Not only the strong NIR emission peaks located at 1548 nm was observed, but also the visible up-conversion luminescence has been found. The specific heat of the Er/Yb:YAB crystal at room temperature is 0.81 J/g °C.     

Comparison of corrosion behavior of zirconium bombarded with self-ion and molybdenum ion

In order to study the effects of zirconium and molybdenum ion bombardment on the aqueous corrosion behavior of zirconium, one group of specimens was implanted with zirconium ions with ions surface densities ranging from 1 × 10¹⁵ to 2 × 10¹⁷ ions/cm² at about 170 °C, using a metal vapor vacuum arc (MEVVA) source operated at an extraction voltage of 50 kV. The other group of specimens was bombarded with molybdenum ion with ions surface densities ranging from 1 × 10¹⁶ to 5 × 10¹⁷ ions/cm² at about 160 °C, using a MEVVA source operated at an extraction voltage of 40 kV. The valence states and depth distribution of elements in the surface of the samples were analyzed by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES), respectively. Polarization curves measurement was employed to evaluate the aqueous corrosion resistance of the zirconium samples in a 1N H₂SO₄ solution. It was found that the aqueous corrosion resistance of zirconium implanted with 5 × 10¹⁶ Zr ions/cm² is the best in first group samples. For molybdenum ion implantation, the aqueous corrosion resistance of samples declined with raising ions surface densities. The natural corrosion potentials of zirconium samples bombarded with self-ions are more negative than that of the as-received zirconium. While, as for molybdenum ion implantation, the results are opposite. Finally, the mechanisms of the corrosion behavior of the zirconium samples implanted with zirconium and molybdenum ions are discussed.     

Preparation of Perovskite-Type Oxides La1-x Srx Fe1-y Coy O3 Using EDTA Sol-Gel Method

Two series of perovskite-type oxides with composition La1-xSrxFeO3 (x≤0.8)and La1-xSrxFe1-yCoyO3( x = 0.2；y = 0.2, 0.4 ) powder productions were synthesized by EDTA complexing sol-gel method. The products were characterized by XRD, TEM, SEM, BET method (N2 adsorption)and laser granularity analysis for different synthesis conditions to obtain the optimum conditions for the preparation process. Single-phased, uniform perovskite-type oxides with small particle size were obtained by EDTA sol-gel process with high stability and repeatability,and the process temperature is much lower than that of solid state reaction method.     

Application of Fourier Analysis to Digital Imaging for Particle Shape Analysis

The shape of aggregates has an important influence on the behavior of civil engineering materials. Digital imaging techniques provide unique opportunities for describing these features in an automated fashion. Shape analysis of fine and coarse aggregate particles is investigated in this study using Fourier transform of digital images. The geometric signature of each shape is extracted by measuring the distance between its centroid and the boundary at constant increment of angles, and Fourier transforms are used to evaluate its spectral information. The number of highest amplitude harmonics required for accurate profile regeneration is evaluated. Shape of a given aggregate particle is reconstructed using inverse Fourier transforms considering a limited number of significant harmonics. A parameter that can quantify the error between regenerated and original profiles is proposed. Using this value, two shape parameters are defined to describe the overall shape and the ruggedness of a particle. A procedure of quantitatively describing the roundness/angularity of aggregate shape is presented and extended to three dimensions using orthogonal views.     

用单片机实现各音色电子琴

介绍了音色概念以及音色的决定性因素。针对传统电子琴采用以滤波网络电路对某次谐波量进行放大或衰减来模拟音色的方法,提出了一种新的实现方案,即采用以单片机为主体的数字电路,"软硬"兼施,模拟音色的波形,再通过D/A输出,从而达到听觉上的模拟音色的目的。解决了传统的模拟音色电子电路的设计的复杂性和多变性问题。给出了具体的实现电路、软件设计方法和步骤。     

Kinematic calibration for a hybrid 5DOF manipulator based on 3-RPS in-actuated parallel manipulator

The measurement method is a decisive step for any calibration method. This paper studies the practical performance of a 5DOF manipulator based on a 3-RPS parallel mechanism. By comparing the controlling data that resides in parallel part and serial part at different orientations, a calibration method has been put forward and proved to be applicable. The precision of the calibrated model mainly depends on the number of measurements carried out. The distribution of measurement points also affects the precision and the measurement number could be significantly reduced if uniform distribution were ensured.     

3G网络基站电磁环境影响分析

通过资料收集、理论预测、数据监测与分析,讨论了辽宁某市3G网络基站中典型基站的电磁环境。结果表明,理论预测与实际监测结果差距不大,各典型基站的电磁辐射功率密度均低于国家标准限值8μW/cm2,对该地区的电磁环境影响不大。对保护环境提出了相应的对策措施.     

Cu(Ⅱ)-3,5-diCl-DMPAP-OP 显色反应及其应用研究

研究了在非离子表面活性剂ＯＰ存在下，２－（３，５－二氯－２－吡啶偶氮）－５－二甲氨基苯酚（３，５－ｄｉＣｌ－ＤＭＰＡＰ）与Ｃｕ（Ⅱ）的显色反应。实验表明，在ｐＨ７．５～１０．０的硼砂缓冲介质中，铜（Ⅱ）与试剂形成１∶２的稳定的红色配合物，其表观摩尔吸光系数ε５５８＝９．７×１０４Ｌ·ｍｏｌ－１·ｃｍ－１，铜浓度在０～６．５μｇ／１０ｍＬ范围内符合比尔定律。在柠檬酸三钠和二酮肟的存在下，可直接用于铝合金和纯铝中微量铜的测定，获得满意结果。     

A Review of ABO3 Perovskite Photocatalysts for Water Splitting

Photocatalysts with perovskites for hydrogen production from aqueous solution were reviewed. Among the most of metal oxide photocatalysts, the family of ABO3 Perovskite-type oxide shows higher photocatalytie activity, especially alkaline earth titanate and alkali tantalate. Therein, sodium tantalate showed the highest activity for water splitting. The reasons for the high photocatalytic activity of ABO3 perovskties are considered to the diverse and flexible crystal structure. The photocatalytic activity of ABO3 perovskties can be improved by doping other element at A site, B site or O site and loading CO-catalysts such as NiO and Pt. In this paper, the mechanism of photocatalytic water splitting, the structure of ABO3 perovsktie, and Perovskite-type photocatalysts were reviewed.     

并行设备总线嵌入式控制系统设计

采用ARM7内核芯片S3C4510的高性能网络控制器结合使用CPLD设计VME总线控制器逻辑时序,研制出了类似3UVME的并行设备总线控制器。开发嵌入式系统uClinux的网络通讯软件,实现提供设备之间高速网络连接通道,把后台计算机数据库和前端设备紧密地连接起来,实现数据的快速获取与给定。