钢结构防火涂料应用中存在的几个问题

在分析钢结构防火涂料应用发展现状的基础上,针对实际应用中影响质量的几个问题进行了剖析,提出了改进的建议。     

膜分离技术大行其道

食品与膜分离技术 膜分离技术是以滤膜作为选择性障碍层，允许某些成分透过而保留混合物中的其它成分。他在食品工业上，主要应用于制造过程中的前处理，去除杂质、除菌、浓缩、澄清、分离，甚至污水处理等。在分离过程中，不涉及相变化及化学变化，具有高效能、节省能源、避免环境污染等特点。膜过滤技术包括逆渗透、     

Kinetics of AuSn4 migration in lead-free solders

The relatively fast diffusion of Au atoms in eutectic PbSn matrix is considered one of the contributing factors to the Au embrittlement problem. In this study, we further investigated the Au embrittlement problem in high-Sn solders. Experimentally, Sn3.5Ag (wt.%) spheres with 500-μm diameter were soldered over the Au/Ni soldering pads. It was found that some of the AuSn₄ needles that formed after reflow inside the solder migrated back to the solder/pad interface during thermal aging. However, the migration kinetics in high-Sn solders was slower compared to that in eutectic PbSn. The difference in migration kinetics of AuSn₄ in eutectic PbSn and SnAg was ascribed to the difference in the magnitudes of the Au flux and the Ni flux. In eutectic PbSn, the Au flux was much greater than that of the Ni flux, and the Au and Ni flux were in the same order of magnitude in eutectic SnAg. The relative magnitude of the Au and Ni flux changed in eutectic PbSn and SnAg because the homologous temperatures of PbSn and SnAg were different.     

Dynamic responses and damages of water-filled pre-pressurized metal tube impacted by mass

An account is given of some principal observations made from a series of experiments in which three-span pipe beams were subjected to central impact by indenters with different nose shapes. These pipes were filled and pre-pressurized with water in order to identify the main effects produced by the fluid–structure interaction. In comparison, the impact experiments of the pipes with no water were also carried out. The perforation failure modes and corresponding critical impact energies were obtained in different test conditions. The experimental results indicated that the critical perforation energy and the deformation of the wall of the pipe were significantly influenced by the presence of the water and the pressure.     

燃料性质对加热炉腐蚀结焦的影响及其防治

从加热炉燃料变化情况入手 ,分析了加热炉目前存在的炉管结垢 ,预热器烟气露点腐蚀以及炉体腐蚀等问题。从机理上进行了探讨 ,从而提出了原油脱金属、燃料气脱硫、燃料油优化、化学除垢以及预热器改造等防护措施。     

用添加剂改善柴油的颜色稳定性

利用实验室筛选出的一种柴油安定性改进剂改善柴油的颜色稳定性。贮存实验表明：成品柴油(催化裂化柴油组分占30％)中加入该剂300～400μg/g，可改善比色0．5-1．5个号，同时可抑制柴油氧化沉渣的生成，改善柴油的氧化安定性和颜色稳定性。     

5V转换成-10V的简单电路

典型开关式电容器充电泵不需要电感器，因此容易设计．且能将正电压加倍及将正电压转换成一个等效负电压。但在某些应用中．只有正电源可用．且电源系统必须产生一个幅度比正电源电压幅度更大的负电压。图1所示电路可将其输入电压反相的同时将所得负电压加倍。     

TD-SCDMA标准化进展

依据演进次序，从3GPP R99、3GPP R4、3GPP R5、3GPP R6和3GPP R7五个方面对TD-SCDMA系列标准进行了概括的介绍，并对各标准的主要特点和新增功能进行了概述。     

纳米羟基磷灰石的合成及分散性能研究

采用中和反应制备羟基磷灰石（HA），在反应过程中添加了六偏磷酸钠、三聚磷酸钠和“快易”作分散剂。采用X射线衍射仪（XRD）、扫描电镜（SEM）、透镜电镜（TEM）、热重和差示扫描分析（TG-DSC）等测试手段对所合成的粉末进行了表征。结果表明：分散剂添加的时间对合成粉末的粒径没有明显的影响；三种分散剂中六偏磷酸钠和三聚磷酸钠的均有较好的分散效果，粉末粒径达到纳米级。