The role of additives in PVC market opportunities

Additives can be used to provide significant performance enhancements to plastics. For PVC, particular performance benefit can be gained from additives that raise HDT, increase impact, improve color fastness, and improve processing. This paper comments on what improvements are desired in these areas, and what benefits and market opportunities would then result.     

硫肥:新的机遇与挑战

列举了硫肥在中国、印度、阿根廷和巴西的应用。大量田间试验证明,SO^2-4或S^0微粒硫肥可显著提高农作物产量。比较了这两类硫肥的优缺点。SO^2-4为速效硫肥,易于被作物吸收,但容易发生淋溶损失。S^0须被微生物氧化成SO^2-4才能被作物吸收,由于这是一个渐进的过程,所以淋溶损失很小;此外S^0产品对后季作物具有良好的后效,这对双季耕作和一种或多种作物的轮作是很重要的。S^0转化成易于被植物吸收的SO^2-4形式受土壤和环境条件的影响。描述了S^0肥的一些新用途,如“种子膨胀”和病虫害的控制。植物养分硫具有良好的海外市场机遇,但高运费、高包装费用、产品在海运途中的破碎,可能使其缺乏可接受性。解决的方法是在有S^0资源的当地建立结构紧凑的模块式造粒装置。     

Superlattices: problems and new opportunities,nanosolids

Superlattices were introduced 40 years ago as man-made solids to enrich the class of materials for electronic and optoelectronic applications. The field metamorphosed to quantum wells and quantum dots, with ever decreasing dimensions dictated by the technological advancements in nanometer regime. In recent years, the field has gone beyond semiconductors to metals and organic solids. Superlattice is simply a way of forming a uniform continuum for whatever purpose at hand. There are problems with doping, defect-induced random switching, and I/O involving quantum dots. However, new opportunities in component-based nanostructures may lead the field of endeavor to new heights. The all important translational symmetry of solids is relaxed and local symmetry is needed in nanosolids.