动静态研究体系中CaCO_3沉积规律的理论分析及实验研究

本文针对冷却水系统污垢研究的两种测试体系 ,对 Ca CO3 沉积规律进行了理论分析与相应的实验研究 ,探讨了两种体系存在差别的根本原因。     

动静态研究体系中CaCO3沉积规律的理论分析及实验研究

本文针对冷却水系统污垢研究的两种测试体系,对ＣａＣＯ３沉积规律进行了理论分析与相应的实验研究,探讨了两种体系存在差别的根本原因。     

输油管线内气液固三相流中沙粒沉积规律的数值模拟研究

以苏丹油田Palouge油区的输油管线参数为研究对象,基于多相流混合模型,采用Fluent软件对输油管线内的气液固三相流中的沙粒沉积过程进行了数值模拟,研究了流速、含沙量、含水量、压力和原油粘度对沙粒沉积规律的影响。结果表明:沙粒在输油管线中的沉积分为起始沉积段、过渡段和稳定段。平均沉沙量随流速、含水量的增大而减小,随含沙量的增大而增加,压力为0.2MPa和原油粘度为0.1 Pa.s时,分别达到51.80%和45.76%极小值。沉沙量最大位置随流速、含水量而右移,随含沙量增大而左移,随着压力和原油粘度增大存在一临界值(0.2MPa时4.28m和0.1Pa.s时3.68m)。过渡段宽度随流速和压力增大存在一临界值,随含沙量、含水量和原油粘度的增大存在极值(8%时22.56m,20%时21.80m和0.1Pa.s时22.19m)。过渡段压差直接影响了过渡段的宽度。流速和含沙量对其沉积规律的影响最大。     

煤液化沥青转化过程中循环溶剂典型供氢组分的相互作用规律研究

为阐明煤液化沥青转化过程中循环溶剂典型供氢组分的相互作用及其对溶剂性能的影响规律,从而为循环溶剂的组成优化提供理论支撑,将二氢蒽（DHA）、二氢茚（IND）分别与四氢萘（THN）混配作为供氢溶剂以考察供氢组分种类及溶剂和沥青质量比（3∶1和5∶1）对煤液化沥青加氢转化行为的影响规律。结果表明：在溶剂和沥青质量比为3∶1和5∶1时,随着混配溶剂中DHA或IND质量分数的增加,油水产率均不断降低,焦产率均先降低后升高,气产率随着DHA质量分数的升高不断降低,而随着IND质量分数的升高则不断升高,氢耗不断升高。此外,随着混配溶剂中DHA或IND质量分数由25%增加到75%,转化率随着DHA质量分数的升高不断降低,而随着IND质量分数的升高逐渐升高。两种混配溶剂中溶剂和沥青质量比为5∶1时油水产率和转化率均低于溶剂和沥青质量比为3∶1时。在溶剂和沥青质量比为3∶1和5∶1的条件下,两种复配溶剂中的油水产率均高于理论值,这说明DHA,IND分别与THN混配在直接液化过程中存在协同作用,DHA和THN复配在溶剂和沥青质量比3∶1时的协同作用较强,而IND和THN复配在溶剂和沥青质量比5:1时协同作用稍强。     

注氮排液过程中环空内气液两相流动型态的实验研究

本文阐述了垂直环空中气液两相流动型态的实验研究对连续油管注氮排液施工的重要作用,分析了整个注氮排液流程的特点,自行设计了可模拟现场施工的垂直环空管路系统及计算机实时数据采集系统,对注氮过程进行了室内实验模拟,获取了大量的实验数据,并绘制了垂直环空管内的流动型态图,为进一步的垂直环空中流动型态的分布规律研究奠定了理论基础,也为现场的施工提供了事实的依据。     

碳化硅陶瓷内筒服役过程中的结构演变和蚀损机理

通过对使用前后的碳化硅陶瓷预热器内筒样品进行扫描电镜显微观察和X射线衍射分析,得出陶瓷内筒在使用过程中的结构演变和蚀损机理.结果表明:碳化硅陶瓷内筒在热烟气的氧化作用下不断被氧化,随后氧化生成的Si02在高速物料的冲蚀磨损作用下断裂、剥落,最终导致的结构损坏.     

SELECTIVE FLAT PLATE COLLECTORS FOR SOLAR DRYERS

ABSTRACT

Five different selective surfaces coated with oxides of nickel, manganese, chromiUm, lead, am iron on galvanized iron substrate by electro-deposition or chemical method were studied for properties such as absorptivity, emissivity, temperature rise of the surface and stagnation air temperature. The properties of the surfaces which may change due to weather conditions were predicted by: subjecting the collector surfaces to accelerated tests. The best among them was found to be black nickel, followed by manganese, chromium, lead, and iron oxides. Black nickel and manganese surfaces were included in the solar drying system and their drying air temperatures recorded. With selective surfaces, a temperature rise between 250to 4sOC was observed depending on the surface (either manganese oxide or nickel oxide)., Hence high mo~sture content food crops can be dried in less than half the time using selective surface     

陶瓷过滤管表面粉尘层清除过程的图像分析

Based on the analysis of high-speed video images, the detachment behavior of dust cake from the ceramic candle filter surface during pulse cleaning process is investigated. The influences of the dust cake loading,the reservoir pressure, and the filtration velocity on the cleaning effectiveness are analyzed. Experimental results show that there exists an optimum dust cake thickness for pulse-cleaning process. For thin dust cake, the patchy cleaning exists and the cleaning efficiency is low; if the dust cake is too thick, the pressure drop across the dust cake becomes higher and a higher reservoir pressure may be needed. At the same time there also exists an optimum reservoir pressure for a given filtration condition.     

扫描电子显微镜在新型陶瓷材料显微分析中的应用

简要介绍了扫描电子显微镜的工作原理; 以铁电陶瓷为例阐述了这种检测仪器在新型陶瓷材料的显微结构分析、纳米尺寸研究及铁电畴的观测领域中的用途,说明了扫描电子显微镜与其他设备的组合以实现多种分析功能的发展趋势和陶瓷材料在扫描电镜分析时的几个常见问题.     

润滑油中机械杂质的扫描电镜／能谱分析

采用溶剂稀释,离心分离获得润滑油机械杂质。利用扫描电子显微镜和X射线能谱仪对润滑油机械杂质进行形态观察和X射线能谱微区元素分析,观察润滑油机械杂质扫描电子显微形态结构及能谱分析结果表明,润滑油机械杂质主要由含C、O、 Al、 Si、 S、 K、 Ca、 Fe的泥块状的细微颗粒组成,随机组的长时间运行,润滑油中含碳纤维杂质有逐渐增多的迹象。     

水泥颗粒生长与黏结的微观分析

水泥微观结果的变化是一个十分复杂的过程,其中包含了水泥颗粒的生长、黏联、絮凝以及其它反应。了解这些水泥颗粒的行为对于更好地掌握水泥基材料早期性能非常重要。采用扫描电子显微镜内安装的Quantomix密封舱系统,原位观察了3种不同的水泥浆体的微观结构。基于这个系统可连续观察水泥浆体微结构发展的优点,研究了水化过程中单个颗粒的生长与颗粒间的连接。通过显微照片的图像分析获得水泥颗粒的灰度变化,用于上述研究。对这些水泥浆体中水泥颗粒的生长与连接情况进行了定量研究。     

Determination of Thermal Properties and Morphology of Eucalyptus Wood Residue Filled High Density Polyethylene Composites

Thermal behaviors of eucalyptus wood residue (EWR) filled recycled high density polyethylene (HDPE) composites have been measured applying the thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Morphology of the materials was also studied using scanning electron microscope (SEM). Addition of the EWR into the recycled HDPE matrix reduced the starting of degradation temperature. EWR filled recycled HDPE had two main decomposition peaks, one for EWR around 350 °C and one for recycled HDPE around 460 °C. Addition of EWR did not affect the melting temperature of the recycled HDPE. Morphological study showed that addition of coupling agent improved the compatibility between wood residue and recycled HDPE.     

Tensile tests in the environmental scanning electron microscope (ESEM) - Part I: Polypropylene homopolymers

Performing tensile tests in an ESEM enables the simultaneous recording of both the force-elongation diagrams and the microstructures forming at the crack tip. Whereas the former are macroscopic parameters, the latter provide information on the micro-scale and are dependent both on the microstructure of the material itself and the test parameters. Changes in the fracture behaviour during a tensile test can be directly observed and correlated with the respective part of the force-elongation diagram.Neat polypropylene samples with varying MFI values and different types of crystal modification and structure were investigated. Videos of the crack propagation at the crack tip clearly show that irreversible deformation already starts at forces far below the maximum load. The size of the spherulites seems to determine the size of the structures developing at the crack tip. Cyclic tests demonstrate that the respective structures can deform elastically, but they do not heal. Furthermore, relaxation experiments prove that relaxation does not take place at the central fracture region but beyond it. Decreasing the specimen temperature below the glass transition temperature of the material provides information about the change in the microstructures at the crack tip involved therewith.     

板式换热器以松花江水为冷却水条件下的污垢特性

为研究板式换热器在天然水下的污垢特性;实验采用BR0.015F型板式换热器;研究了其在不同的流速和温度下的污垢特性;用扫描电镜观察了已经结垢的换热表面。结果表明:此板式换热器松花江水的污垢类型为渐进型且不存在诱导期;随着流速的增大污垢热阻降低的幅度减小。冷却水温度在27.5～28.5 ℃时污垢热阻较大;温度升高污垢热阻降低;换热表面的混合污垢成片的附着于换热面;有少量的难溶盐析出的晶体生成。     

Development of new techniques for scanning electron microscope observation using ionic liquid

Based on our previous discovery that ionic liquid (IL) can be observed by a scanning electron microscope (SEM) without charging the liquid, we have developed several novel techniques for SEM observation. Coating of insulating sample with IL is useful for providing electronic conductivity to the samples like metal or carbon coating by vacuum vapor deposition. In this case, dilution of the IL with appropriate volatile solvent like alcohol is effective for coating thin layer of IL on the sample. As a biological sample, seaweed including IL was attempted to be observed by SEM. A seaweed leaf swollen by water was put in an IL bath and the bath was put in an outgassed desiccator to replace water in the seaweed leaf with IL. The resulting sample gave a SEM image of the swollen seaweed whose thickness was several times larger than dried one. Furthermore, the introduction of the IL in vacuum chamber allowed us to develop the in situ electrochemical SEM observation system. Using this system, we observed changes in polypyrrole film thickness caused by the redox reaction of the film and the electrochemical deposition of silver and its oxidative dissolution. It was also found that the energy dispersive X-ray fluorescence (EDX) analysis was available even for the electrode polarized in IL.