PHASE HOLDUPS AND LIQUID-LIQUID EXTRACTION IN THREE PHASE FLUIDIZED BEDS

Effects of the continuous phase velocity (0.01-0.08 m/s(, the dispersed phase velocity (0.0-0.04 m/s) and particle size (1.0-3.0 mm) on the individual phase holdups and the mass transfer coefficient have been determined in two (liquid-liquid) and three (liquid-liquid-solid) phase fluidized beds.

In the beds, the dispersed phase holdup increased with dispersed phase velocity but it decreased with continuous phase velocity. Whereas the continuous phase holdup decreased with dispersed phase velocity but it increased with continuous phase velocity. The bed porosity increased with both the dispersed and continuous phase velocities in the beds of 1.7 and 3.0 mm particles. In addition, the continuous phase holdup decreased with the presence of solid particles in the bed, however, the dispersed phase holdup was not affected by the presence of the particles.

The overall mass transfer coefficients in the continuous and dispersed phases increased with increasing fluid velocities but it decreased with the bed height.

The continuous phase holdup and mass transfer coefficient data have been correlated with the operating variables and the dimensionless groups.     

分子印迹技术在固相萃取中的应用与展望

20世纪90年代以来,具有构效预定性、特异识别性和广泛实用性等特点的分子印迹技术在异构体及手性分离、化学仿生传感器、模拟酶催化、膜分离及固相萃取等领域的研究较多. 固相萃取技术作为一种比液液萃取更好、更快速、更简便的分离技术,是近30年来才快速发展起来的.以印迹聚合物作为固相萃取填料是分子印迹技术最具应用前景的一个方向.对分子印迹技术及固相萃取技术的基本原理及方法进行了简单介绍,并着重介绍了近年来分子印迹技术在固相萃取中的应用,如环境样品分析、药物分离与分析、生物与临床医学检测等,并对两种技术结合取得的成果、面临的问题及应用前景进行了展望.     

荷电有机超滤膜处理金属离子溶液过程中离子强度的影响

以KCI溶液为代表,考察了压差对电位差的影响;测定了聚砜中空纤维超滤膜（截留分子量为6k）在KCl、NaCl、MgCl2、CaCl2和AlCl3背景电解质液中的等电点;研究了不同性质溶液的离子强度对流动电位、膜渗透性、离子截留率及△pH值的影响.结果表明：电位差随压差呈线性递增;膜等电点仅与金属离子价态有关;离子强度影响着流动电位,进而与膜渗透性、离子截留率及△pH密切相关.     

聚硅酸复盐混凝剂在有机高浓度废水处理中的应用

研究了由固体废物（炼铁废渣和炼钢废渣）制取的两种聚硅酸复盐混凝剂处理有机高浓度废水,结果表明,这两种聚硅酸复盐混凝剂不仅处理效果好,工艺简单,成本低廉,而且可以达到以废治废的目的,同时提高了废水的可生化性,为废水的后续处理打下了良好的基础。     

建筑涂料用高固体分乳液的研究

通过调整配方和聚合工艺,研制了固体分〉６５％的高固体分乳液,特别适宜配制外用厚涂建筑涂料。讨论了诸如乳化剂、引发剂、酸性单体用量、加料方式等乳液聚合因素对乳液性能的影响。     

连铸用高强度复合定径水口的研制

通过对配方和工艺的调整，成功地研制出高强复合定径水口，其整体与复合体结构紧密，提高了复合体的抗热震性，克服了镶嵌式水口的缺陷，并提高了水口的耐用性。     

高熔体强度聚丙烯的研究进展

综述了国内外采用接枝与交联改性法制备高熔体强度聚丙烯(HMSPP)的研究进展。分析了目前采用接枝与交联改性PP所存在的问题,指出硅烷接枝交联改性技术的成本适中,产品质量好,是获得HMSPP的最有希望的改性技术。     

无酯基树脂高固体分汽车涂料

介绍了无酯基树脂——多异氰酸酯多元醇齐聚物用HMMM交联固化,避免了酯键带来的弱点,可获得耐酸雨性的高固体分汽车涂料。     

高熔体强度聚丙烯研究进展

综述了国内外熔体强度聚丙烯（HMSPP）的研究进展和应用前景,重点介绍了为获得长链支化的高熔体强度聚丙烯一般采用的方法,如树脂掺混,射线辐射,化学交联和聚合过程中引发接枝等,并简述了国外高熔体强度聚丙烯在熔融热成型,挤出涂布和发泡等方面的应用。     

苯酚在浊点萃取中凝聚层相的增溶规律

采用分光光度法测定了苯酚在非离子表面活性剂单相胶束溶液中和在非离子表面活性剂两相浊点萃取时凝聚层相中的增溶结果.实验表明：溶质在凝聚层相的增溶与表面活性剂形成胶束的结构有关.当凝聚层相的表面活性剂形成正相胶束时,溶质在凝聚层相的增溶规律和在表面活性剂胶束溶液中的增溶规律一致;当凝聚层相的表面活性剂形成反相胶束时,溶质在凝聚层相和在溶液相的浓度关系可理解为在这两种溶剂之间的分配随着凝聚层相的含水率逐渐降低趋近于一定值,溶质的分配系数也趋近于一定值.     

THE BEHAVIOR OF THE DISPERSED PHASE IN LIQUID-LIQUID EXTRACTION IN FLUIDIZED BEDS

An investigation was carried out on the effects of liquid flow rates, solid particle size, bed height, and voidage on the dispersed-phase holdup, the drop size and the behavior of the dispersed phase in liquid-liquid concurrent fluidized beds. The mass transfer coefficients were calculated from liquid-liquid extraction data and the calculated results could be satisfactorily explained by matching with the dynamic behavior of the liquids and the change of drop size. The increase of liquid-liquid extraction rates in liquid-liquid fluidized beds was mainly due to the increase of interfacial areas of the dispersed phase.     

高温环境下蜂窝夹层结构埋件拉脱性能研究

介绍了常温环境下和高温环境下蜂窝夹层结构埋件拉脱性能的试验和结果,对比分析了高温环境对埋件拉脱性能的影响。结果发现,埋件在受法向拉脱力时,高温环境中承载力下降为常温的8%左右,且失效模式也发生了变化,由常温的蜂窝芯剪切破坏变为面板与蜂窝芯脱粘破坏;埋件在受面内拉脱力时,常温环境和高温环境下埋件分别呈现出了两种典型的失效模式,常温环境中失效模式为面板压缩破坏,高温环境中失效模式为面板皱褶失稳破坏,且拉脱力降为常温的28%左右。     

抑制高强混凝土受火爆裂的措施

提出了定量表征混凝土受火爆裂程度的方法,研究了4种纤维、1种聚合物乳液和2种防火涂层对硅灰和粉煤灰高强混凝土受火爆裂的抑制效果。研究表明：单丝状、直径较小的聚丙烯纤维可有效抑制爆裂。提出了包裹于纤维表面的混凝土柱的直径计算方法,并定量描述纤维掺量和直径对抗爆裂的影响。孔结构分析表明：添加物能有效抑制爆裂的一般表现为混凝土试件受火后孔隙率显提高,最可几孔径发生明显偏移,并且此最可几孔占有一定的数量。防火涂层抗爆裂具有一定的效果,抗爆裂效果与涂层本身性能有关。     

应用模糊控制理论综合评定高强混凝土的抗冻性能

现有的抗冻评估标准在适用于同强混凝土方面已显得不足，而这一问题必将随着高强、同性能混凝土的逐步推广应用日益突出，采用了能分别体现混凝土内部抗浆、外部抗冻以有韧性大小的3个指标（即陡然劣化特征点对应的冻融循环数，质量损失率以有最大曲率值）来综合衡量混凝土的抗冻性能，在试验的基础上，应用了先进的模糊控制理论以上述3指标作为输入向量对高强混凝土的抗冻性能作进行了综合评定。结果表明，该方法用于同强混凝土的抗冻评定更为客观和合理。另外，在模糊控制计算的基础上，提出了简化经验计算公式，该公式可直接进行高强混凝土抗冻性的评估。     

方型状态方程在高压相平衡中的研究及应用

对近年来状态方程的研究及其在高压相平衡计算中的应用状况作了综述分析。以ＰＲＳＶ方程为基础，通过实际计算考察和评价不同混合规则在复杂体高压汽液平衡、超临界流体／固体体系相平衡计算中的性能     

Bi系高Tc超导相的研制

在液氨温区的YBaCuO体系超导研究正处于高潮之际,C.Michel等人给出了非稀土的Bi-Sr-Cu-O体系,发现Bi_2SrCu_2O_(7+(?))在7—22K出现超导电性转变。之后,H.Maeda等人宣布制备出名义组分为BiSrCaCu_2O~y超导体,起始转变温度为105K,而零电阻温度在70K引起了世界各国超导工作者们极大的注意。我国科学院物理所的科学工作     

《缠绕用高强玻璃纤维无捻粗纱》标准介绍

为了方便各方对 JC/T 953-2005《缠绕用高强玻璃纤维无捻粗纱》行业标准的理解和使用,文章对该标准的范围、编制原则作了介绍,并对主要技术内容和与国内外同类标准水平的对比等作了详细的阐述。文章相信该标准的制订和实施, 对推动我国高强玻璃纤维的健康发展具有重要意义。     

COMPLEXATION OF STRONTIUM IN THE SYNERGISTIC EXTRACTION SYSTEM DICYCLOHEXANO-18-CROWN-6, VERSATIC ACID,CARBON TETRACHLORIDE

The synergism in the extraction of Sr? +? from 0.5M Sr(NO?3?) ?2? by 0.05M dicyclohexano-18-crown-6 (DC18C6) + 0.1M Versatic 1519 (abbreviated v-acid or RCOOH, a neo carboxylic acid) in CCl?4? has been found to stem from a strong 1:1 interaction between DC18C6 and Sr?2+ ? However, both nitrate and carboxylate can function as the anion for the (DC18C6)Sr?2+? moiety. At aqueous conditions corresponding to less than complete loading (i.e., [Sr?2+?[ org < 0.05M for pH < 11.7), (DC18C6)Sr(NO?3;)?2? precipitates as a solid. As the pH is raised in the interval 7 < pH < 11.7 to deprotonate the V-acid, the precipitate (DC18C6)Sr(NO?3?) ?2? becomes solubilized first with probable formation of a mixed-anion complex and finally with quantitative (0.05M) formation of the monoraeric complex (DC18C6)Sr(OOCR) ?2? H?2?O at pH = 11.7 as confirmed by viscometric titration of 0.05M DC18C6 in wet CCl?4? with Sr(OOCR) ?2?, Karl-Fischer titrations, vapor-phase osmometry, and IR spectrophotometry.     

AN EXPERIMENTAL STUDY OF PHASE DISTRIBUTION AND TURBULENCE STRUCTURE FOR SOLID/LIQUID FLOW IN A HORIZONTAL PIPE

Local measurements of the velocity and phase distribution were made for solid/liquid two-phase flows in a horizontal pipe using a multidimensional laser Doppler anemometer (LDA) system. The pipe used had a 30.6 mm inner diameter and was made of a special optically clear material, Fluorinated Ethylene Propylene (FEP), which has the same index of refraction as water. The test section and laser probes were submerged in water so that no optical corrections were necessary. Simultaneous measurements of the liquid and particle phases were obtained and discriminated based on differences in the residence time that each particle had when crossing the LDA's measurement volume.

Positive buoyant and negative buoyant solid spherical particles, about 2 mm in diameter, were used in this study. A complete data set of the phasic mean velocities, turbulence and volume fractions were taken for each particle type.

The results presented herein are complete and self-consistent, and can be used to assess the predictive capabilities of multidimensional two-fluid computational fluid dynamic (CFD) models.