Preparation of Silver Nanowires via a Rapid,Scalable and Green Pathway

Rapid synthesis of silver nanowires(Ag NWs) with high quality and a broad processing window is challenging because of the low selectivity of the formation of multiply twinned particles at the nucleation stage for subsequent Ag NWs growth.Herein we report a systematic study of the water-involved heterogeneous nucleation of Ag NWs with high rate(less than 20 min) in a simple and scalable preparation method.Using glycerol as a reducing agent and a solvent with a high boiling point,the reaction is rapidly heated to 210 ℃ in air to synthesize Ag NWs with a very high yield in gram level.It is noted that the addition of a small dose of water plays a key role for obtaining highly pure Ag NWs in high yield,and the optimal water/glycerol ratio is0.25%.After investigating a series of forming factors including reaction temperature and dose of catalysts,the formation kinetics and mechanism of the Ag NWs are proposed.Compared to other preparation methods,our strategy is simple and reproducible.These Ag NWs show a strong Raman enhancement effect for organic molecules on their surface.     

Rare-earth free sensitizer in NaLuCrF4:Er upconversion material

Upconversion phosphors are known as a material system that can convert near-infrared light into visible/ultraviolet emissions by sequentially absorbing multiple photons. The studies on upconversion materials often use two rare earth (RE) ions as a sensitizer-activator pair. We investigated the influences on luminescence intensity depending on Cr-doping content (x) of hexagonal NaLu_0.98–xCr_xF₄Er_0.02 (x = 0–0.9) upconversion material by substituting Lu³⁺ ions with Cr³⁺in the absence of Gd³⁺. The change in upconversion luminescence intensity appears with saddle-like shape. We suggest that Cr³⁺ ions play the dual role as a constituent in host lattice and a sensitizer in the upconversion process. Optimal conditions for gaining the strongest upconversion emission correspond to x = 0.3–0.5, where there are effective energy transfers between Cr³⁺ and Er³⁺ ions and CrEr dimers. Apart from these values, the emission intensity decreases rapidly which can be ascribed to the absence of multiple-photon absorption for the case of low Cr³⁺ contents, and to the coupling between Cr³⁺ and/or Er³⁺ ions for the case of high Cr³⁺ contents. Magnetization and electron-spin-resonant measurements were performed to understand the correlation between the optical and magnetic properties.     

张海潮副总裁在中国石化销售企业技能竞赛和技术比武活动总结表彰大会上的讲话(摘要)

1 2006年竞赛比武活动的简要总结 这次中国石化销售企业职业技能竞赛和技术比武活动，是销售系统组建以来历时最长、参赛人数最多、规模最大的一次全员大练兵，今年又是竞赛比武的第一年，时间紧、任务重。在总部领导及有关部门的关心支持下，各级销售企业高度重视，精心组织，经过8个多月的辛勤努力，圆满完成了本年度竞赛比武的各项任务，取得了阶段性的成果。回顾今年的竞赛比武活动，主要有以下三个特点：     

合成氨中置锅炉的修复

本文在分析中置锅炉失效原因的基础上，提出了详细的修复措施，为类似情况的设备修复提供了借鉴。     

评定飞航导弹单发命中概率的方法研究

通过对抽样检验方法的研究,确立了区间估计的下限公式,用来在已知样本值的情况下确定导弹单发命中概率出现在该区间内的置信水平和精确度。     

电子称在化工生产中的应用

针对化工生产环境的特点对电子称重仪器在化工计量中的正确选择和使用作一些分析阐述。     

高温对冶金窑窑体的影响

针对冶金回转窑窑体在高温下产生的失效进行数值分析，并在此基础上对冶金窑窑体的设计方法进行修正。     

位置控制器与通用变频器APC系统

在每一周期的开始时的速度值V1预设定到传动装置上进行速度预控制，同时，反馈回来的实际值Sj与S1进行比较计算，得出当时偏差值△S，此偏差值△S乘以比例系数Ksp，得到Vk叠加在Vt上，得出传动装置应具有的速度控制信号V，然后V经速度／电压变换和D／A转换向传动系统的速度控制发出控制信号Uα控制执行机构的定位。调节Ksp的值使系统无超调无振荡。     

丙酮低压一步法合成甲基异丁基酮催化剂体系研究进展

对丙酮低压一步法合成甲基异丁基酮所需要的催化剂体系及反失活机理进行了详尽的综述，并对近年来的研究工作进行了系统地分析与比较，提出了未来的研究方向。