C5/C6烷烃异构化Pt/Al2O3-Cl催化剂的性能

采用浸渍法制备了Pt/Al₂O₃,在300℃、CCl₄氯化1h,制备出Pt/Al₂O₃-Cl催化剂。采用FT-IR、XRD、TEM、CO-IR、Py-IR和TPD等方法表征了催化剂,并与中温型RISO催化剂的催化性能进行比较。结果表明,在氯化处理过程中氯取代了氧化铝的表面羟基,导致3000～3800cm^-1红外吸收峰强度大幅度减小,但催化剂的晶相不发生改变;氯化使Pt粒子的平均粒径增大,粒径分布变宽,金属分散度降低;氯化后金属Pt主要以+2价的PtCl₂的形式出现,其中一部分生成了易升华的PtCl₂·2AlCl₃,从而导致Pt含量降低;氯化后的催化剂上只有L酸,评价后既有L酸,又有B酸;氯化后的催化剂热稳定不高,随着温度升高,3种类型的氯化物相继脱出;Pt/Al₂O₃-Cl相对于中温型RISO催化剂表现出较好的异构化性能,正己烷转化率达88.17%,2,2-二甲基丁烷选择性达29.68%,裂化和氢解几乎没有发生。     

TiO_2/沸石与活性炭三维粒子电极体系光电催化研究

采用溶胶-凝胶法制备沸石负载TiO2(TiO2/沸石)。将TiO2/沸石与活性炭按照不同比例混合为粒子电极,采用钛网作为主电极,硫酸钠溶液为助电解质,紫外灯为光源建立了三维电极光电催化体系,处理亚甲基蓝模拟废水。实验表明:当电极间距为4.0 cm、TiO2/沸石∶活性炭=2∶3、亚甲基蓝的初始浓度为3 mg/L,灯距为10 cm、电压为2.0 V、电解质浓度为0.04 mol/L、初始p H=6.0,光催化降解效率可达49.5%。三维电极光电催化效果优于二维电极光电催化与光催化效果。Fe3+离子掺杂提高了体系的光电催化效率,最大光电催化效率可达53.3%。     

硫酸钛液稳定性分析及偏钛酸粒度控制研究

测试了硫酸法钛白生产中系列浓度钛液在不同温度下的稳定性;并根据系列稳定性数据调节水解工艺,在水解初期适当延长升温时间,水解后期加入适量的稀碱液。用激光粒度分析仪、扫描电子显微镜测定偏钛酸的粒度分布及粒子形貌。结果显示,调节工艺后得到的偏钛酸粒度分布曲线的半峰宽缩小,整体均匀性较好;扫描电子显微镜照片显示调节工艺对小粒子的产生有明显抑制作用;水解率达到97.0%。     

Investigation and simulation of a cross-flow air classifier

Extensive experimental tests and a computational study of the performance in a cross-flow air classifier have been carried out. A computational fluid dynamics (CFD) package—Fluent—is used to first understand and explain why the cuts or the sharpness of cut of this classifier are not as sharp as they ought to be, and then to optimize the geometry and operational conditions.

Flow fields of the classifier under various set-up conditions and geometry were measured by using laser Doppler anemometry (LDA). Using sieve analyses and the HELOS-laser method, the patterns of behaviour of separation parameters such as cut size and sharpness of cut have been investigated at different boundary conditions.

Using the Fluent package, a two-dimensional computational fluid dynamics model has been developed. The model is based on the Euler–Lagrangian approach. Different turbulence models have been tested. Both Fluent 4.5, with a structured grid, and Fluent 5.1, with structured and unstructured grids, have been used.

Discussions and analyses of the experimental, as well as the computational results, are presented. The simulation with a structured grid shows good agreement with experimental data, except for the sharpness of cut. The reasons of poor performance of the classifier have been found. The geometry is optimized and other conditions were also improved. The performance of the classifier is improved. The experimental observations together with the computed results should increase the depth of understanding of the underlying mechanisms.     

Changes in the Cuticular Hydrocarbon Profile of the Slave-Maker Ant Queen, Polyergus breviceps Emery, After Killing a Formica Host Queen (Hymenoptera: Formicidae)

Queens of the slave-maker ant, Polyergus breviceps, take over nests of their Formica host species by fatally attacking the resident queen. As workers only begin grooming the P. breviceps queen once she has ceased her attack, we investigated whether a change in parasite queen chemistry may account for the change in worker behavior. Cuticular hydrocarbon profiles of newly mated P. breviceps queens and of queens of their two Formica host species were found to be species-specific. Profiles of newly mated P. breviceps queens that had attacked a Formica queen, however, were virtually identical to the queen profile of the species killed. Mass spectral analysis revealed that the hydrocarbons on the cuticles of newly mated P. breviceps changed from primarily normal alkanes to methyl and di-methyl branched alkanes after attacks. The results suggest that cuticular compounds from the host queen were transferred to the parasite queen during their aggressive interaction.     

Microwave-Hydrothermal Synthesis of Nanocrystalline Zirconia Powders

Nanosized zirconium oxide (ZrO₂) powders were prepared by adding NaOH to a zirconyl chloride aqueous solution under microwave-hydrothermal conditions. The obtained results showed that the tetragonal polymorph increased with increasing NaOH concentration in the starting solution and reached the maximum value by using 1 M ZrOCl₂. The microwave-assisted hydrothermal synthesis is expected to be able to process continuously, and may lead to energy savings because of rapid heating to temperature and increased kinetics of crystallization. This method is very simple and can lead to powders with desirable characteristics such as very fine size, narrow size distribution, and good chemical homogeneity.     

利用聚氨酯泡沫复合废料制造板材的研究

用热压工艺将汽车车顶饰件生产过程中的聚氨酯泡沫复合废料制成板材,研究了板材的性能与热压工艺之间的关系。试验结果表明,当热压温度为150℃以上时,板材的弯曲强度可以达到15－28MPa,板材的吸水率为0－2％,密度为1．0－1．2g/cm^3,其强度与中密度纤维板相当,密度则高于纤维板,吸水率大大低于纤维板。这种板材可望在分园设施,家具,音呼同材料方面获得应用。     

内构件对高密度提升管内流体力学及径向气体混合的影响

Effect of bluff internals on the hydrodynamics and lateral gas mixing was studied in a 0.186m ID high-density riser. With the bluff internals, the extremely non-uniform radial profiles of solid fraction and particle velocity become flat and the dense downflow layer near the wall disappears, indicating the significant enhancement of solid turbulence introduced by the internals. The fluctuation velocity and solid fraction transient signal analysis indicates a significant increase in fluctuation intensity near the wall region. The length influenced by the internals on the flow structure is about 1 meter. The lateral gas dispersion coefficient increases significantly as the bluff internals exist in the riser.     

微细级磷酸锌生产新工艺

利用表面改性技术，改进直接法生产磷酸锌，不用粉碎，得到０．０３７ｍｍ以下微细颗粒及均匀颗粒度分布产品，表观密度～０．４ｇ／ｃｍ３，Ｚｎ及ＰＯ４含量指标满足国外最新标准要求，运用正交试验优化工艺条件。     

Changes in the Peeled Surfaces of Copper Thin Films Deposited on Polyimide Substrates After Heat Treatment

Peel strength between a copper (Cu) thin film and a polyimide (pyromellitic dianhydride-oxydianiline, or PMDA-ODA) substrate is reduced by heat treatment at 150°C in air. In this work, we investigated the peel strength, the morphology of the interface between Cu films and polyimide substrates using optical microscopy and electron microscopy, and chemical change of the interface using Auger electron spectroscopy (AES) and micro X-ray photoelectron spectroscopy (XPS). The analysis showed that CuO “lumps” were present on the peeled surface of PMDA-ODA after heat treatment at 150°C in air. The peeled surfaces of other polyimide substrates were also analyzed: biphenyl dianhydride-para phenylene diamine (BPDA-PDA) and biphenyl dianhydride-oxydianiline (BPDA-ODA). CuO lumps were present on the peeled surface of BPDA-ODA after the heat treatment, but not that of BPDA-PDA. Compared with the adhesion strength for the Cu thin film, the adhesion strength was high for the Cu/PMDA-ODA and Cu/BPDA-ODA laminates, but the adhesion strength was very low for the Cu/BPDA-PDA laminate. This low strength is the reason that CuO lumps were not detected on the peeled surface of the BPDA-PDA substrate. These CuO lumps were related to the adhesion degradation of the Cu/polyimide laminates after the heat treatment.