镁碱沸石结晶度及晶体形貌的影响因素

以硅溶胶为硅源,偏铝酸钠为铝源,乙二胺为模板剂制备镁碱沸石.考察了晶化温度、晶化时间、碱度、陈化时间和晶种加入量对镁碱沸石结晶度和晶体形貌的影响.用X射线衍射仪(XRD)、扫描电子显微镜(SEM)等对所合成的样品进行了表征.结果表明:在碱度为0.12~0.15、晶化温度为160 ℃、晶化时间为60 h的条件下能够合成出晶化良好的样品;随着晶化温度的升高样品结晶度先升高后降低,其晶体尺寸逐渐增加;随着晶化时间的延长样品的结晶度和晶体尺寸先增加后趋于稳定;适当温度的陈化可以减小晶体尺寸,而添加晶种则可以显著改变晶体的形貌和尺寸.     

Product-centered processing: Manufacture of chemical-based consumer products

A systematic framework for product-centered processing is useful particularly in developing chemical-based consumer product manufacturing processes. The objective is to provide directions and guidelines toward the development of a process for manufacturing a product with the desired performance in reduced time and effort. The product performance, represented by several quality factors, is related to product ingredients and structural attributes, as well as the process flowsheet and operating conditions. The procedure consists of five steps. First, the product functionality, form, and packaging are defined. Second, relevant quality factors are identified. Third, necessary ingredients are selected and product microstructure is determined. Fourth, the manufacturing process is designed in light of the desired product properties. Limitations on achievable product quality are also identified. Finally, the product and process are evaluated with the help of experimental data. The framework is illustrated using industrial examples, including the production of dry toner, laundry detergent, shampoo, and cosmetic lotion.     

A three-chamber electrochemical cell facilitated biogas upgrading and high-purity oxygen production

Journal of Applied Electrochemistry - Anion exchange membrane (AEM)-equipped electrochemical cells can be used for removing the carbon dioxide (CO2) from biogas, thereby upgrading its energy...     

Pd/Ce0.6Zr0.4O2/Al2O3 as advanced materials for three-way catalysts: Part 1. Catalyst characterisation, thermal stability and catalytic activity in the reduction of NO by CO

Pd-loaded Ce_0.6Zr_0.4O₂ solid solutions supported on Al₂O₃ are investigated as catalysts for the reduction of NO by CO. The attention is focused on the role of the Ce_0.6Zr_0.4O₂ and of the Pd dispersion on the catalytic activity. The system shows a very high activity below 500 K, which is almost independent on the Pd dispersion. The high activity is attributed to a promoting effect of the Ce_0.6Zr_0.4O₂ on the NO conversion. Investigation of the influence of high temperature treatments disclosed a thermal stabilisation of both Ce_0.6Zr_0.4O₂ and Al₂O₃ in the Ce_0.6Zr_0.4O₂/Al₂O₃ system.     

The Instrumented Indentation Study of HVOF-Sprayed Hardmetal Coatings

Elastic-plastic properties, namely, hardness and Young’s modulus, of four HVOF-sprayed hardmetal coatings were measured by instrumented indentation using Oliver-Pharr method Nanoindenter XP MTS with a continuous stiffness measurement (CSM) module. The results show that with sufficient number of CSM measurements, one can distinguish between indents made in the hard particles and indents made in the binder material. This can be accomplished by analyzing the plots of hardness and Young’s modulus versus load (or versus indentation depth). Further development of the dependence curves enables the load (or indentation depth) to be set to correspond to the point of transition from a single structure component to the composite material and to determine the properties of both. Comparison of results of CSM measurement with the results of single indentation measurement at a defined load reveals a new perspective on the origin of the indentation size effect in hardmetal coatings. The measurements show that the increase in both the hardness and Young’s modulus with decreasing load is caused mainly by the predominant influence of hard particles in the coatings.     

Phenolic compounds and antioxidant activity of extracts of Ginkgo leaves

The aim of the present study was to determine the flavonol contents of crude extracts from Ginkgo (Ginkgo biloba L.) leaves, their antioxidant properties in model system studies, and their inhibitory action of linoleic acid oxidation in an emulsion system and of triacylglycerols (TAG) in rapeseed oil. Extracts were prepared from both green and yellow leaves of Ginkgo trees using water, aqueous acetone, and ethanol. Extracts were analyzed by HPLC for their presence and content of selected flavonols; these included myricetin, quercetin, kaempferol, isorhamnetin, and morin. The highest level of flavonols, especially quercetin, myricetin and kaempferol, were found in the aqueous acetonic extracts. Crude extracts from yellow Ginkgo leaves contained greater amounts of flavonols. The best DPPH radical‐scavenging activity amongst the Ginkgo extracts examined was determined for aqueous acetonic extracts, while the lowest was noted for the ethanolic extract of green leaves. Water infusion extracts exhibited the highest iron(II) chelating activity. The reducing power of extracts from yellow leaves was 2 higher than that of crude extracts from green leaves. Nevertheless, extracts from green Ginkgo leaves imparted a greater protection factor against TAG oxidation, as assessed by the Rancimat method. Crude extracts from yellow Ginkgo leaves were more efficacious than green ones at inhibiting oxidation of the linoleic acid emulsion.     

动力髋螺钉手术治疗股骨粗隆间骨折的临床效果分析

目的探讨动力髋螺钉手术治疗股骨粗隆间骨折的临床效果。方法对我院95例股骨粗隆间骨折患者采用DHS治疗。结果本组患者手术时间90～240min,平均140min,出血量100～600mL,平均220mL。均获得随访,随访时间为6～40个月,平均12个月。93例骨折均愈合,2例延迟愈合,与过早负重有关,限制活动后骨折愈合。平均愈合时间为3个月。完全负重时间为5个月,无伤口感染、褥疮、无骨不愈合、髋内翻发生,无螺钉穿出股骨头、退出、钢板断裂及变形。本组优75例,良18例,差2例,优良率为97.9%。结论DHS是治疗股骨粗隆间骨折内固定器械中的首选,手术时间短,内固定牢靠,减少了卧床并发症及髋内翻发生,缩短了住院时间,疗效可靠,值得临床推广应用。     

Duplex positioning method for increasing the fatigue life of threaded connections under eccentric loading

A new method, duplex positioning method DPM, to increase the fatigue lifetime of the threaded connection under eccentric loading is presented. When DPM is applied, the most damaged stud regions periodically are removed from risky positions by a change of the stud’s and nut’s mutual position in the axial direction alongside with a change of the stud’s position in respect to bending plane. The mathematical model for DPM enables us to predict its efficiency. To simulate the fatigue strength of the stud the following was used: Patterson’s and Kenny’s thread deflection factors, solutions for the distributions of the axial load and bending moment along the threads, Neuber’s method for the stress concentration factors in multiplier notches, Heywood’s formulas for the stress due to the thread flank loading and for the combined stresses, as well as the results of the photoelastic analysis of the araldite models under eccentric loading.