球状纳米硅氧化物的制备

以硅、二氧化硅为原料,采用水热沉积法制备了球状纳米硅氧化物。用扫描电子显微镜、透射电子显微镜、能量色散谱仪、荧光光度计等测试手段观测了样品的形貌,分析了样品的成分、结构及光致发光（PL）特性。扫描电镜、透射电镜的研究结果表明,所得样品为高纯、直径较均匀的球状纳米硅氧化物。选区电子衍射结果表明,所得纳米硅氧化物球为无定形结构。PL测试表明,样品具有较强的蓝光发射能力。     

一种异形分流锥的加工

数控线切割机床加工解决了很多传统加工难以解决的难题,尤其是在带锥度平面切割的产品加工过程中更具优势,已广泛应用于塑料模具、航空、航天等工业领域。本文介绍了一个实例,希望读者可以在这加工方法中得到一些启示。     

CuO对木粉/PVC复合材料热解和燃烧过程中烟释放行为的影响

采用热重分析法、锥形量热仪测试及Py-GC-MS联机方式研究了CuO对木粉/PVC复合材料(WF-PVC)热解和燃烧过程烟释放行为的影响.实验结果表明,WF-PVC热解过程具有PVC热解的特性;与WF-PVC相比,用CuO处理WF-PVC能明显提高第1阶段质量损失,降低第2阶段的质量损失,提高成炭量;WF-PVC燃烧过程中烟释放速率和总烟量低于PVC,用CuO处理WF-PVC总烟量降低更显著;Py-GC-MS分析结果表明,与PVC相比,WF-PVC以及用CuO处理的WF-PVC,燃烧气相组分中芳香族化合物含量分别降低52.29%和49.34%;加入CuO,抑制了气相组分中多环化合物的生成.     

Volume of a liquid drop detaching from a sphere

A theoretical and experimental study is conducted to investigate the detached volume from a pendant drop on the surface of a sphere. Observation of drop detachment by high‐speed video camera reveals that the movement of the upper part of the neck of the drop is quite slow compared to that of the detaching lower part. The surface profile of the upper part was calculated approximately as a static problem using the axisymmetric Laplace equation. Using the drop profile, the system energy, including the work done by the solid–liquid wetting behavior, was calculated. Based on the condition of minimum energy, the volume of the detached part V was calculated. The volume V increases with the sphere diameter and approaches the value for the pendant drop attached to a plate. In addition, V is strongly dependent on the wettability between the sphere and the liquid and decreases with the receding contact angle. The detached volume of the water drop was measured for spheres of porous brick of various diameters. The experimental and theoretical results were found to be in good agreement. © 2010 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/htj.20305     

用锥形量热仪研究聚氨酯泡沫的阻燃性能

在50 kW/m2辐射功率下,利用锥形量热仪研究了氢氧化铝、卤系阻燃剂、氮系阻燃剂和磷系阻燃剂阻燃聚氨酯泡沫(PUF)的阻燃特性,获得了点燃时间、最大热释放速率、总热释放、比消光面积及质量损失速度等参数。结果表明,将热释放速率、燃烧总释放热和烟气释放量作为材料阻燃性能好坏的评价指标,阻燃剂聚磷酸铵（APP）和三聚氰胺磷酸盐（MP）是PUF的理想阻燃剂。     

风积沙地基工程性质及其输电线路基础抗拔设计

沙漠风积沙地基工程性质及其输电线路杆塔基础抗拔设计是当前我国电网建设中的关键研究课题之一。通过对我国不同沙漠风积沙地基的物理力学性质的试验及其研究成果的统计,分析了我国沙漠地区风积沙地基的颗粒级配组成及其分类,给出了其含水性、容重、孔隙性、相对密度、内摩擦角等典型物理力学特性参数的平均值。基于我国沙漠风积沙地基的工程特性,介绍了沙漠风积沙地基输电线路杆塔基础抗拔稳定性“土重法”设计方法及其正确性。研究并分析了宁夏毛乌素沙漠4 个斜柱扩展基础上拔水平力组合荷载试验、新疆塔克拉玛干沙漠4 个装配式基础上拔水平力组合荷载试验、内蒙库布齐沙漠1 个直柱扩展基础和2 个混凝土拉线盘基础抗拔试验成果,得到了我国典型沙漠风积沙地基极限上拔角标准值为16.9°;在考虑地基抗拔承载力分项系数为1.65 的基础 上,得到风积沙地基上拔角设计值为10.3°。由于该上拔角设计值综合考虑了风积沙地基的区域特征、基础类型、基础几何尺寸、基础荷载工况等不同影响因素,可作为我国沙漠地区输电线路基础设计的依据。     

热敏CTP曝光参数中的斜排角度的设定及分析

使用适用于激光密排斜排热敏CTP的测控条,对国产热敏CTP的曝光参数中的激光密排斜排角度进行设定及研究,并分析了斜排角度对制版质量的影响。结果表明,激光密排斜排角度设置不正确,印版图文信息会发生扭曲、变形,影响制版质量。     

Template-free fabrication of SnO2 hollow spheres with photoluminescence from Sni

SnO₂ hollow spheres with interstitial Sn²⁺ defect were fabricated by the hydrothermal method without any surfactant or polymer, whose shell is constructed by two layers of tetragonal prism nanorod arrays. The growth mechanism of the hollow spheres was investigated and attributed to the nucleation and arrangement of SnO₂ tetragonal prism nanorods on the surface of the hydrothermal reaction formed NO bubbles in the aqueous solution. After illumination by 275 nm wavelength light, narrow peak emissions centered at about 587-626 nm have been found in the photoluminescence spectrum, which have been ascribed to the interstitial Sn²⁺ defect in the SnO₂ hollow spheres.     

惯性圆锥破碎机概述

惯性圆锥破碎机是一种具有独特原理和结构的新型节能超细破碎设备,可实现物料的选择性破碎,满足多碎少磨新工艺的要求。文中简述了惯性圆锥破碎机的结构特点、工作原理及工作参数对性能指标影响,并通过实例证明了该机在粉碎工程领域中的良好应用前景。     

用斜投影法解决相交的几个问题

运用斜投影法解决直线与平面,直线与锥面、平面与斜棱锥,平面与椭圆柱,正圆锥与椎圆柱等相交,求交点,交线的作图问题。