激光二极管抽运Nd:GdVO4微片激光器

报道了一种新型激光二极管（LD）端面抽运Nd：GdVO4微片激光器，测量了抽运输入功率与激光输出功率的关系，激光阈值功率为83mw，在2W的抽运功率下得到860mw的1.064μm基横模连续激光输出，光-光转换效率为43％，最大斜度效率达到47％。     

To increase the lifetime of electroluminescent (EL) device by low-temperature deposition of organic thin solid films

We have studied the electrical and light-emitting behaviour as well as the lifetime of electroluminescent (EL) cells which consist of naphthoylimide (NPL) as the emitting layer and poly(3-octythiophene) (P3OT) doped with poly(N-vinylcarbazoe) (PVK) as the hole transport layer sandwiched between indium-tin-oxide (ITO) and aluminium (Al) electrodes. The mixed polymer (P3OT : PVK) layer and the emitting layer were deposited by spin coating and by vacuum deposition. When the ITO substrate was cooled to near liquid N2 temperature during the deposition of the NPL emitting layer, the brightness of the cells increased. Characterized by atomic force microscopy (AFM), the emitting layer became more amorphous as the deposition temperature decreased. Results collected show that low temperature deposition of organic thin solid films would be a powerful technique for not only the enhancement of electroluminescent brightness but also increasing the lifetime of EL devices. © 1998 Kluwer Academic Publishers     

Photoluminescence and doping mechanism of theranostic Eu3+/Fe3+ dual-doped hydroxyapatite nanoparticles

Theranostic nanoparticles currently have been regarded as an emerging concept of ‘personalized medicine’ with diagnostic and therapeutic dual-functions. Eu³⁺ doped hydroxyapatite (HAp) has been regarded as a promising fluorescent probe for in vivo imaging applications. Additionally, substitution of Ca²⁺ with Fe³⁺ in HAp crystal may endow the capability of producing heat upon exposure to a magnetic field. Here we report a preliminary study of doping mechanism and photoluminescence of Eu³⁺ and Fe³⁺ doped HAp nanoparticles (Eu/Fe:HAp). HAp with varied concentration of Eu³⁺ and Fe³⁺ doping are presented as Eu(10 mol%):HAp, Eu(7 mol%)-Fe(3 mol%):HAp, Eu(5 mol%)-Fe(5 mol%):HAp, Eu(3 mol%)-Fe(7 mol%):HAp, and Fe(10 mol%):HAp in the study. The results showed that the HAp particles, in nano-size with rod-like morphology, were successfully doped with Eu³⁺ and Fe³⁺, and the particles can be well suspended in cell culture medium. Photoluminescence analysis revealed that particles have prominent emissions at 536 nm, 590 nm, 615 nm, 650 nm and 695 nm upon excitation at a wavelength of 397 nm. Moreover, these Eu/Fe:HAp nanoparticles belonged to B-type carbonated HAp, which has been considered an effective biodegradable and biocompatible drug/gene carrier in biological applications.     

基于可见/近红外反射光谱的稻米品种与真伪鉴别

利用可见/近红外光谱技术对市场上5种稻米进行了鉴别.以ASD FieldSpec3地物光谱仪采集了5种稻米的光谱数据,各获取35个样本,随机分成训练集(150份)和检验集(25份),并分别采取全波段与特征波段(400~500nm、910~1400nm与1940~2300nm)两种方法建立模型进行分析.光谱经S.Golay平滑和标准归一化(SNV)处理后,以主成分分析法(PCA)降维.将降维所得的前9个主成分数据作为BP人工神经网络(BP-ANN)的输入变量,稻米品种作为输出变量,建立3层BP-ANN鉴别模型.利用25个未知样对模型进行检验,结果表明两类模型预测准确率均高达100%,其中特征波段模型比全波段模型具有更高的预测精度,说明利用可见/近红外技术结合PCA-BP神经网络分析法进行稻米品种与真伪的快速、无损鉴别是可行的,且提取特征波段是优化模型的有效方法之一.     

Synthesis of nanocrystalline cubic substoichiometric WC1 − z powders by mechanochemical technology

Nanocrystalline cubic substoichiometric WC_{1 – z} powders were synthesized by a mechanochemical method at room temperature, a process of highly reactive energetic ball milling of WO₃ + 3Mg mixtures containing excessive graphite as a source of carbon for W phase. The excessive graphite plays a very important role in the formation of cubic phase, otherwise the h.c.p. phase is formed. The entropy evaluation shows that the reduction reaction is a self-propagating process. After millimg for 90 hours and excluding MgO from the product by using HCl solution, the cubic substoichiometric WC_{1 – z} powders containing a little excessive graphite with the grain size in the range of 4 to 20 nm were obtained.     

钛离子掺杂对LiFePO4结构和性能的影响

为提高LiFePO4的充放电性能，用Ti（Ⅳ）对LiFePO4进行掺杂．用电化学方法测量了Li1-xTixFePO4的充放电性能，用X射线衍射和里特沃尔特方法表征了掺杂LiFePO4的晶体结构．固相反应可以制备单相Li1-xTixFePO4（x=0．00、0．01、0．02、0．03、0．05和0．07，摩尔分数），其中Li0．98Ti0．02FePO4具有更好的电化学性能，在80mA／g的充放电电流下，第2次的放电比容量为136．606mAh／g，循环20次后为128．388mAh／g．研究表明，少量钛离子掺杂不仅改变了原子间距和位置、引起晶胞收缩，而且增加了LiFePO4中Fe^3＋／Fe^2＋共存态的浓度，提高了材料的导电能力，从而能有效地提高LiFePO4的比容量和循环性能．     

La0.68Pb0.32FeO3纳米材料在低工作温度条件下对CO气体的气敏性研究

采用sol-gel法制备了具有正交钙钛矿结构的La0.68Pb0.32FeO3和LaFeO3纳米粉体.用该粉体制成气敏元件,并测试了该粉体材料在CO气体中的气敏特性,测试结果表明：与LaFeO3相比,La0.68Pb0.32FeO3具有更小的粒径、较大的电导值、对CO气体具有更好的气敏性能,特别是工作温度大大降低.与空气中相比,在CO气体中,材料La0.68Pb0.32FeO3的导电激活能增大.     

Message Queuing Markup Language for Enterprise Integration

With the advent of dynamic e-business and its open standards-based supporting technologies, valuable legacy applications that support essential business processes in enterprises can join this new area of distributed computing. Message Queuing allows applications to use components that communicate with one another using queued messages. In this paper, we propose an extensible Message Queuing Markup Language (MQML), which is a major component of the Software Integration Markup Language (SIML) for enterprise integration with Universal Web Services model. A research prototype is presented to validate the effectiveness and value of our proposed MQML for enterprise integration.     

Linker-free layer-by-layer self-assembly of gold nanoparticle multilayer films for direct electron transfer of horseradish peroxidase and H2O2 detection

Au nanoparticle (AuNP) multilayer films were fabricated by combining interfacial assembly and layer-by-layer assembly. The key point is that the procedure does not require assistance of organic linker molecules, thus providing a suitable platform for the modification of biological molecules. Direct electron transfer can easily take place between a glassy carbon electrode and horseradish peroxidase (HRP) molecules adsorbed on AuNP films. The current density of direct electron transfer was closely related to the layer number, m, and reached a maximum value for m = 4. The optimized HRP/AuNP multilayer film had a relatively rapid response and satisfactory selectivity for H₂O₂ detection. The linear range and the detection limit were 9.8 × 10⁻⁶ to 6 × 10⁻³ mol/L and ∼4.9 × 10⁻⁶ mol/L (S/N = 3), respectively.