The effect of apatite and elemental sulphur mixtures on growth and P content ofCentrocema pubescens

Two glasshouse pot experiments and one incubation experiment were undertaken to measure the effectiveness of Sri Lanka (Eppawala) apatite rock phosphate as a fertilizer for the perennial legumeCentrocema pubescens. The apatite was applied alone, or as a mixture with elemental sulphur and soil containingThiobacelli bacteria either as powder or pellets that were either uncoated or coated with rubber (to reduce the rate of release of P thereby increasing P release for a longer-term).Application of apatite to the soil significantly increased DM yields of shoots and P content (yield × P concentration) in shoots. Application of sulphur andThiobacelli bacteria with the apatite caused further increases in yield and P contents of shoots. Pelletizing the apatite and sulphur together with a soil inoculum ofThiobacillus did not increase dry matter yields of shoots or P content of shoots compared to a mixture of apatite and sulphur in the powder form. Incubating the mixture in powder or pellet form in the laboratory increased water-soluble P extracted and decreased the pH of these mixtures. Pellets of the mixture when coated with rubber released P more slowly during incubation, but growth ofCentrocema pubescens treated with coated pellets was comparable with that for uncoated pellets.     

Effect of algicides on urea fertilizer efficiency in transplanted rice

The effects of the algicides terbutryn and copper sulfate on the potential for reducing the gaseous loss of NH₃ from urea applied to rice were examined in experiments with 2 methods of N fertilizer management, 2 or 3 N rates, and 3 algicide treatments. The experiments were conducted during the 1986 dry and wet seasons in an experimental field at Pila, Laguna, Philippines.Copper sulfate had little effect as an algicide at the rate used, but terbutryn immediately reduced algal growth. The populations of species resistant to terbutryn probably increased, but terbutryn had no long-term effect on the total number of colony-forming units of algae. There was some evidence that terbutryn reduced photodependent N₂ fixation as estimated by acetylene reduction assay.Terbutryn, when applied with urea 10 days after transplanting, reduced the maximum floodwater pH by 0.9 units or more for 7 d in the DS and by about 0.5 units for 8 d in the WS. Terbutryn increased the ammoniacal-N (AN) concentration in the floodwater 100% or more in the DS and 60% in the WS. The combined effect of terbutryn on the floodwater pH and AN concentration was reduced photodependent NH₃ partial pressure (NH₃), about 25% in the DS and 38% in the WS. deceased     

Resolving the unresolved complex mixture in motor oils using high-performance liquid chromatography followed by comprehensive two-dimensional gas chromatography

High-performance liquid chromatography (HPLC) followed by comprehensive two-dimensional gas chromatography (GC×GC) was used for detailed group-type characterization of hydrocarbons present in motor oils. With conventional GC, motor oil is not well separated due to its complexity, resulting in a “hump” in the chromatogram: the unresolved complex mixture (UCM). With HPLC-GC×GC, motor oil hydrocarbons can be quantitatively separated into four major groups: alkanes, cycloalkanes, alkenes and aromatics. Each group can be further separated and divided by ring number or carbon number. Three selected motor oil samples were characterized by HPLC-GC×GC including two conventional motor oils and a synthetic motor oil. Using a proprietary silver-modified HPLC column, the aromatic components in motor oils were baseline separated from the aliphatic UCM and were then further separated by GC×GC based on their aromatic ring numbers. Accordingly, the aliphatic components were separated by GC×GC based on their saturated ring numbers. This paper illustrates the capabilities of HPLC-GC×GC for reliable and detailed quantitative group-type characterization of hydrocarbons present in motor oils.     

Eu-Doped BaTiO3 Powder and Film from Sol-Gel Process with Polyvinylpyrrolidone Additive

Transparent BaTiO₃:Eu³⁺ films were prepared via a sol-gel method and dip-coating technique, using barium acetate, titanium butoxide, and polyvinylpyrrolidone (PVP) as modifier viscosity. BaTiO₃:Eu³⁺ films ~500 nm thick, crystallized after thermal treatment at 700 ºC. The powders revealed spherical and rod shape morphology. The optical quality of films showed a predominant band at 615 nm under 250 nm excitation. A preliminary luminescent test provided the properties of the Eu³⁺ doped BaTiO₃.     

聚晶金刚石复合片功能的微结构调控研究

随着聚晶金刚石复合片的推广使用,对复合片的整体性能和某些特殊功能的要求均有提高.文章根据金刚石复合片不同使用环境的要求,结合金刚石复合片的主要性能指标,提出了功能型聚晶金刚石复合片的概念.由于聚晶金刚石复合片不同的显微结构可反映其不同的功能性,结合其影响因素对金刚石复合片的显微结构进行调控,实验结果表明,通过对聚晶金刚石复合片功能的微结构调控,可以优化和突出其磨耗性能、抗冲击性能或者耐热性能,从而满足PDC钻采工具切削齿对不同工况微环境的功能性要求.     

From the ganglioside GQ1balpha to glycomimetic antagonists of the myelin-associated glycoprotein (MAG)

The tetrasaccharide 4, a substructure of ganglioside GQ1balpha, shows a remarkable affinity for the myelin-associated glycoprotein (MAG) and was therefore selected as starting point for a lead optimization program. In our search for structurally simplified and pharmacokinetically improved mimics of 4, antagonists with modifications of the core disaccharide Galbeta(1-3)GalNAc, as well as the terminal alpha(2-3)- and the internal alpha(2-6)-linked neuraminic acid were synthesized and tested in target-based binding assays. Compared to the reference tetrasaccharide 4, the most potent antagonist 17 exhibits a 360-fold improved affinity. Furthermore, pharmacokinetic parameters such as stability in the cerebrospinal fluid, logD and permeation through the BBB indicate the drug-like properties of antagonist 17.     

Heterogeneous Catalysis in Biodiesel Production: The Influence of Leaching

The catalytic performances of several solid catalysts in the transesterification of vegetable oils with methanol were studied in small steel vials. The eventual presence of an homogeneous contribution to the catalysis—due to the leaching of the active phase—was also investigated. The behaviour of one of the more promising catalyst (TiO₂ supported on SiO₂) was further deepened in batch and continuous reactors by using the catalysts in pellets, to evaluate the possibility of developing an industrial process based on this catalyst. The catalyst life-time run, in a continuous tubular reactor, was determinant for this evaluation.     

ZnCl2离子液体催化合成六氯环三磷腈

ZnCl_2与氯化吡啶构成一类具有Lewis酸性离子液体,以其为催化剂,五氯化磷与氯化铵在氯苯中合成了六氯环三磷腈。与ZnCl_2催化体系相比,不仅显著地加快了反应速率,而且明显提高了六氯环三磷腈的收率。当ZnCl_2与吡啶卤化物物质的量比为6:4、反应温度为132℃、反应时间3.1 h时,六氯环三磷腈收率为80.95%。分离后的离子液体真空提纯后,重复使用4次其催化活性基本保持不变。     

全面提高化工原理课堂教学质量的研究与实践

教学质量是高等学校永恒的课题。本文围绕这个主题深入研究,树立一个理念,提出两个互动,进行三个融合,坚持四点做法,旨在全面提高教学质量。     

上方侧注式双辊铸轧辊套温度场的数值模拟

通过数值模拟,对上方侧注式双辊铸轧机的轧辊辊套温度场进行了研究。研究表明,通过将模拟结果与实测数据的比较,验证了模型的可靠性;在铸轧过程中,轧辊外表面温度随着轧辊的旋转发生周期性的变化;当上、下辊套厚度均为40mm时,上、下辊套的温度分布差异较大,下辊套温度明显比上辊套温度高;加强冷却对辊套温度场的影响较小;减小辊套厚度,辊套的温度降低,但辊套内、外表面温差增大;增加熔池与上辊套的接触弧长度,上辊套温度增大。