基于成本优化的天然气长输管道管径、压力比较研究

随着天然气市场的迅速发展,大口径、高压力管道是天然气长输管道未来的发展趋势。如何选择合适的管径和压力成为减少项目投资、提高经济效益的关键因素。讲述如何通过费用现值法进行管径、压力方案比选,来选择成本最优的方案,通过分析研究得出在一定条件下,天然气长输管道建设项目费用成本与管道压力、管径选择之间的关系。以某天然气管道工程为实例,对不同管径和压力的方案进行比较研究,用费用现值法找到最优方案,即成本最优、经济效益最大的方案,为项目投资者追求投资效益最大化做出正确的决策提供重要依据。     

纳米铁酸锌/丙氨酸改性聚乳酸复合磁性微球的制备和表征(英文)

以改进液相化学法合成铁酸锌纳米磁流体来代替传统的铁氧化物磁粉,同时以D,L型丙交酯与丙氨酸为单体进行本体聚合,得到氨基酸改性聚乳酸,再以改性聚乳酸包封纳米磁流体构建磁性高分子微球。采用X射线衍射、傅立叶红外光谱仪、核磁共振仪、扫描电镜、透射电镜、振动样品磁强计、热重分析仪等对所合成的材料进行表征。结果表明:所制备的材料为尖晶石型的ZnFe2O4纳米晶,粒径为20～45nm,磁饱和强度为32×10-3A.m2;丙氨酸成功接枝到了聚乳酸链上;铁酸锌纳米磁流体/聚乳酸复合微球的分散性较好,粒径为80～300nm,聚乳酸的包覆率为45.5%,磁饱和强度为10.6×10-3A.m2,ZnFe2O4经改性聚乳酸封装后仍然保持较好的磁饱和强度。     

碳纤维布上负载钨酸铋的光催化性能

以柔韧性和耐腐蚀性强的碳纤维布为载体,通过水热法将Bi(HO3)3·5H2O和Na2WO4·2H2O制备的前驱液负载在碳纤维布表面,在不同温度下进行焙烧处理制备了负载型纳米钨酸铋光催化剂,利用SEM、XRD和分光光度计等对制备的催化剂进行表征,并采用农药厂废水和罗丹明B等模拟污水进行光催化降解实验.结果表明,焙烧温度为...     

斜向板块运动和大陆构造

三维变形必定与斜向板块汇聚有关,三维变形通常也引起板块边缘处收缩和横推分量之间的变形的分块。转换挤压和转换拉张的走滑分块运动学模式确定了3个关键参数(板块运动、瞬间应变轴和走滑分块程度)之间的准确关系。对两个端员构造环境(即低走滑分块程度的新西兰南岛和高走滑分块程度的加利福尼亚中部)的应用证实这一个参数存在明显的一致性,同时还表明这两个地区的变形应用走滑分块转换挤压这一模式是很有效的。在以扭动变形为主的系统中,如加利福尼亚中部,所出现的极高的走滑分块程度应该与有限和瞬间应变轴的基本错位有关。     

超支化聚酯改性酚醛树脂的制备与固化性能研究

以三羟基丙烷和二羟甲基丙酸为原料,缩聚反应制备了超支化聚酯（HBPE）,并制备了酚醛树脂/HBPE（PF/HBPE）共混体系。采用红外光谱、差示扫描量热分析等方法表征了HBPE的分子结构和PF/HBPE共混体系的性能,并用非模型等转化率法Flynn Wall Ozawa (FWO)描述了PF/HBPE共混体系的活化能与转化率之间的关系。结果表明,由于PF的酚羟基和HBPE的羟基产生了氢键作用,PF/HBPE共混体系显示出单一的玻璃化转变温度,HBPE的加入,提高了PF固化物的冲击强度和弯曲强度,当HBPE的含量为15 %时,冲击强度和弯曲强度分别为4.5 kJ/m2 和77.84 MPa。     

一种新的计算浮顶油罐蒸发损耗方法

针对浮顶油罐的油品蒸发损耗计算问题,提出了一种新的计算方法,通过实例计算分析,与传统的计算方法相比较,新的计算方法更科学,为油库的设计与管理提供理论依据。在此基础上提出了新的降耗方案,得到相应的结论。     

Surface topography of La-Ti composite oxide nanocrystallines examined with atomic force microscope

1　INTRODUCTIONAtomicforcemicroscope (AFM )isakindofscanningprobemicroscope(SPM )derivedfromscan ningtunnelmicroscope(STM ) [1,2 ] .Basedontheprinciplethatoscillationfrequency (ω)ofatomsap proximatestoorismorethan 10 13Hz ,theatomicmass (m )isamountto 10 2 5kg ,theatomicforcee lasticconstantk =ω2 m ,whosescaleis 10N/m ,thereforewithanelasticconstantlessthanatomice lasticconstant,theprobecantilevertipperformsfric tionactionwiththesamplesurface ,thecantileverfluctuatesaccordingtotheap…     

Strain-induced orientation of copper oxide nanoislands through decomposition of pre-organized copper nitrate

By the decomposition of copper nitrate at 400℃, oriented islands of copperoxide crystals were suceessfully fabricated on the amorphous glass surface. X-ray diffraction (XRD), atom force microscope (AFM), and X-ray photoelectron spectroscopy (XPS) confirm the presence of copper oxide islands. The formation of oriented island structures is attributed to the following reasons: 1) the mismatch between the glass substrate and the copper oxide crystals during the relaxation of thermal expansion leads to the formation of islands; 2) the preorganized copper nitrate particles in the voids of colloidal crystals determine their ordered spatial distribution; 3) the strain of the glass substrate developing during calcination provides the driven energy for the orientation of copper oxide crystals along the same direction.     

Fabrication of 2D and 3D dendritic nanoarchitectures of CdS

The controlled preparation of two-dimensional （2D） and three-dimensional （3D） dendritic nanostructures of CdS was reported. 2D dendritic pattems are obtained through the self-assembly of nanoparticles under the entropy-driven force. 3D dendritic needle-like nanocrystals are prepared through an aqueous solution synthesis regulated by oleic acid molecules. Their growth mechanism is presumed to be the selective binding of OA molecules onto growing crystal planes. Techniques such as SEM, TEM, XRD, and FT-IR were employed to characterize the morphologies and structures of the obtained products.