CaAl2O4：Eu^2＋，Nd^3＋纳米粉体的合成与表征

采用溶胶一凝胶法制备了CaAl2O4：Eu^2＋，Nd^3＋纳米粉体发光材料。样品的XRD和SEM分析结果表明：800℃已形成CaAl2O4晶相；样品颗粒尺寸随灼烧温度升高而增加，平均粒径约为20nm～40nm。光谱分析表明：样品的激发光谱为240nm～400nm的宽带谱，在256．6nm和330．6nm处有激发峰。发光光谱是386nm～500nm的宽带谱，峰值位于440nm，与CaAl2O4：Eu^2＋，Nd^3＋粗晶材料相比，光谱发生了“蓝移”现象。样品的热释光峰值位于206℃，与粗晶材料相比，峰值向高温移动了96℃，热释发光峰曲线形状也变宽。样品的发光衰减是由初始的快衰减和随后的慢衰减构成，余辉时间为5h。     

塑料用有机硅材料的研究进展

综述了国内外在塑料用有机硅材料的制备、应用等方面的研究进展,介绍了有机硅材料在塑料改性加工中的用途,并展望了塑料改性用有机硅材料的研究及发展趋势.     

A low complexity algorithm of blind estimation of convolutional interleaver parameters

Interleaving plays an important role in many wireless communication systems,which is used to cope with burst errors and improve the reliability of data transmission.In this paper,we propose a new method to blindly estimate the parameters of convolutional interleaver in a non-cooperative context.The proposed method exploits both the property of interleaved stream and the deinterleaving technique.The product of the depth and width of the interleaver is firstly determined by analyzing interleaved data stream.Then the interleaved data stream is let to pass through a series of reconstructed deinterleavers.Thus the delay,the depth and width of the convolutional interleaver can be estimated by analyzing the deinterleaved data streams.Compared with other algorithms,the proposed method significantly reduces the searching scope and improves computational efficiency.Simulation results show that the algorithm has good performance even if errors exist.     

改进小波阈值去噪法在谐波检测中的应用

针对电力系统谐波检测中传统的软、硬阈值去噪方法不能有效的解决噪声干扰的问题,提出了一种新的去噪算法:改进软硬阈值折衷法。对模拟的电力系统信号分别采用传统的硬、软阈值法、软硬阈值折衷法和文中方法进行Matlab仿真,定量对比分析得出结论:改进软硬阈值折衷法能够更好的解决噪声干扰问题,去噪信号的的信噪比得到提高,均方根误差得到减少,重构后信号能更好还原原始信号,去噪效果好,实用价值较高。     

原子吸收法测定槐花和香椿芽中微量元素含量

用灰化法处理样品，配制混合标准系列溶液，采用空气-乙炔火焰原子吸收法在同一试液中测定10种微量元素含量。建立了优化的仪器测试条件，方法的回收率均在97．3％～102．1％，RSD为1．1％～2．5％，测定方法简便、灵敏、准确，结果满意。     

基于Pro/E三维标准定位、夹紧元件库的建立

传统的专用夹具设计都是根据国标二维图样来完成的,随着CAD技术的日趋成熟,三维造型技术应用已越来越普及,采用Pro/E提前建立好三维标准定位、夹紧元件库,可大大缩短设计周期,降低产品开发及设计成本。     

连栋温室西、甜瓜一年三茬无土栽培试验研究

有机生态型无土栽培技术是指不用天然土壤,而使用基质,不用传统的营养液灌溉作物根系,而使用有机固态肥并直接用清水灌溉作物的一种先进栽培技术.其主要特点是,能提高作物的产量与品质,减少农药用量,对环境无污染,节水节肥省工,利用非可耕地生产瓜、菜等.     

西安生漆涂料研究所30年发展概况

本文概述了从事漆树和生漆资源应用研究和产业开发的专业研究所-西安生漆涂料研究所30年的发展历程和研究概况。主要从三个发展阶段,即:1、欣逢盛世,彰显生机(1980-1985);2、坚守阵地,积极进取(1986-2005);3、描绘新蓝图,而立再辉煌(2006-2010)对漆树资源和生漆研究项目和成果推广应用进行了概述,并提出了研究所发展的工作思路和未来展望。     

Vibration properties and transverse shear characteristics of multibody molded beetle elytron plates

Science China Technological Sciences - This study utilized cantilever experiments to investigate the vibration properties of multibody molded beetle elytron plates (BEPs), which is a type of...     

Luminescent properties of Na2GdMg2(VO4)3:Eu3+ red phosphors for NUV excited pc-WLEDs

Herein, a series of novel Na₂GdMg₂(VO₄)₃:Eu³⁺ (NGMVO:Eu³⁺) red phosphors were elaborated by conventional solid-state reaction process. Their structural features, luminescent properties, energy transfer were researched at length. XRD patterns indicate that NGMVO:Eu³⁺ crystallized in single cubic garnet structure. Under the excitation of near ultraviolet light at 356 nm, the emission spectra of NGMVO host could be divided in two parts that resulted from ³T₂ → ¹A₁ and ³T₁ → ¹A₁ transitions of VO₄^3?. While NGMVO:Eu³⁺ phosphors show intense sharp red emission peaks including 590, 610, 652 and 706 nm that originated from ⁵D₀ → ⁷F_J (J = 1–4) transitions of Eu³⁺, respectively. The optimal concentration of Eu³⁺ is 0.7. Importantly, NGMVO:0.7Eu³⁺ sample presents high energy transfer efficiency (89 %) and high external quantum efficiency (48.3 %). Besides, its emission intensity remains 79 % at 420 K compared with that at 300 K, proving the good thermal stability of phosphors. All above results suggest that NGMVO:Eu³⁺ red phosphors have latent applications in white light emitting diodes.