A ratiometric fluorescent sensor for zinc(II) with high selectivity

Spectroscopic studies revealed that the compound [N,N′-di(quinoline-2-methylene) -1,2-phenylenediimine] (1) exhibited a rather high selectivity toward Zn²⁺ over other metal ions, even Cd²⁺. In acetonitrile, the red shift of fluorescent emission from 396 nm to 426 nm upon zinc binding is due to the formation of a 1:1 metal/ligand complex.     

Atom transfer radical polymerization of n‐butyl methacrylate in an aqueous dispersed system

Atom transfer radical polymerization of n‐butyl methacrylate (BMA) was conducted in an aqueous dispersed system with different kinds of copper complexes. The partitioning behavior of the copper complexes, including CuCl/4,4′‐di(5‐nonyl)‐2,2′‐bipydine (dNbpy), CuCl₂/dNbpy, CuCl/2,2′‐bipydine (bpy), CuCl₂/bpy, CuCl/bis(N,N′‐dimethylaminoethyl)ether (bde), and CuCl₂/bde between the monomer (BMA), and water was studied in detail with ultraviolet‐visible spectroscopy. The results show that with a less hydrophobic ligand, such as bpy or bde, most of the Cu(I) or the Cu(II) complexes migrated from the BMA phase to the aqueous phase, the atom transfer equilibrium was destroyed, and the polymerization was nearly not controlled; it converted to classical emulsion polymerization. As to the very hydrophobic ligand dNbpy, although the partitioning study of the copper complexes indicated that not all the copper species were restricted to the organic phase, the linear correlation between the molecular weight and the monomer conversion and the narrow polydispersities confirmed that the polymerization was still quite well controlled. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3175–3179, 2003     

考虑邻近建筑物影响的内撑式排桩基坑支护局部破坏研究

基坑开挖与周围环境相互影响,而邻近建筑物对基坑支护体系局部破坏的影响鲜有研究。通过内撑式排桩支护砂土基坑模型试验,研究了坑外有、无建筑物两种情况下基坑开挖、支撑局部破坏和桩后砂土渗漏对内撑式排桩基坑支护体系受力及变形性能的影响。试验结果表明：受邻近建筑物的影响,随基坑逐渐开挖,平行于邻近建筑物长边的支护桩桩顶水平位移增大,而垂直于邻近建筑物长边的支护桩桩顶水平位移减小,同时基坑中部内支撑轴力明显增大,角撑次之,边撑反而减小;邻近建筑物对平行于建筑物长边的支护桩桩身弯矩及反弯点影响较大,而对垂直于建筑物长边的支护桩桩身弯矩影响较小;局部内支撑破坏引起的坑外地面沉降较小,而内支撑连续破坏导致坑外地面产生显著沉降,影响范围为0.12~0.23倍开挖深度,同时临近的未失效支撑轴力显著增大,易引发连续破坏;邻近建筑物对平行于建筑物长边的支护桩桩身弯矩影响较大,对垂直于建筑物长边的支护桩桩身弯矩影响较小。当桩后砂土出现渗漏时,对平行于邻近建筑物长边的支护桩影响更为明显。     

基于云端协同计算架构的边缘端I/O密集型虚拟机资源分配方案

大型制造业生产车间业务流程复杂,传统固定资源配置方式将产生负载不均衡的问题。针对此问题,设计并实现了一种基于云端协同架构的边缘端I/O密集型虚拟机资源的分配算法,通过定义计算节点中每个I/O密集型虚拟机三个维度的信息计算得出I/O密集型虚拟机的优先级,并按最大优先级队列实时统一分配硬件资源。实验结果表明,该算法在应对工业机械设备高响应和高通量的要求上有较为明显的提升,为实际生产起到了优化资源配置的作用。     

Rapid synthesis of palm-based monoacylglycerols

Rapid synthesis of high-purity MAG from refined, bleached, and deodorized palm stearin (RBDPS) via chemical glycerolysis in the presence of pyridine was developed to obviate the conventional molecular distillation in the production of pure MAG. The optimal reaction for the sodium methoxide-catalyzed glycerolyis of RBDPS was recorded at 110°C using a 3 wt% catalyst concentration based on the weight of RBDPS, with an RBDPS/glycerol ratio of 1∶2 and an RBDPS/pyridine ratio of 1∶4. High yields of over 99% were achieved rapidly in 15 min, and increases in DAG and FFA were observed after a prolonged reaction time.     

农药残留薄层色谱分析中的显色技术

农药残留特别是剧毒有机磷农药残留一直是国内外农药科技工作者比较关注的一个课题。显色技术是农药残留薄层分析技术发展迅速的关键 ,对显色技术作了较为系统全面的介绍     

助催化剂对BCZ-108催化剂聚合行为的影响研究

在铝钛物质的量比为25、50、100、150、200、300条件下,研究丙烯聚合用BCZ-108催化剂的聚合行为及聚丙烯的主要性能,并与常规应用的NA催化剂进行对比。结果表明,随着铝钛物质的量比的增大,两种催化剂的聚合反应速率的衰减越来越快,聚丙烯的立体定向性越来越低,熔点越来越低,分子量分布越来越宽;BCZ-108催化剂的聚合活性比NA催化剂高30%以上;两种催化剂的聚合活性在铝钛物质的量比为50时达到最高,此时BCZ-108催化剂的活性为1 212 g·g^-1,NA催化剂的活性为907 g·g^-1。     

Effect of porous structure and surface functionality on the mercury capacity of a fly ash carbon and its activated sample

The effect of porous structure and surface functionality on the mercury capacity of a fly ash carbon and its activated sample has been investigated. The samples were tested for mercury adsorption using a fixed‐bed with a simulated flue gas. The activated fly ash carbon sample has lower mercury capacity than its precursor fly ash carbon (0.23 vs. 1.85 mg/g), although its surface area is around 15 times larger, 863 vs. 53 m²/g. It was found that oxygen functionality and the presence of halogen species on the surface of fly ash carbons may promote mercury adsorption, while the surface area does not seem to have a significant effect on their mercury capacity.     

处理硝基苯类废水的Fenton催化氧化技术研究现状

硝基苯类化合物是高毒性物质,难以生物降解且对生化反应有抑制和毒害作用.因此,硝基苯对环境的污染问题越来越受到科学研究者的关注.目前,采用Fenton氧化技术降解硝基苯类化合物的机理和工艺研究越来越活跃.作者就近几年来国内外Fenton催化氧化技术降解硝基苯类废水的研究现状进行了综述.     

浅谈水泥原料山坡露天矿开拓方案的设计

开拓设计方案是矿床开采设计中影响全局性的大问题,直接影响初期建设投资、生产运营成本和资源的合理利用。文章在介绍矿山开拓方案的设计原则、考虑因素和常用方法的基础上,重点对大型水泥生产企业配套的石灰石矿和砂岩矿开拓方案的论证进行了分析介绍。