Experimental determination of mechanical properties and short-time creep of AISI 304 stainless steel at elevated temperatures

The high temperature properties of AISI 304 stainless steel were studied. Basic data about the employed experimental equipment, testing procedures, and specimen geometry were given. The experimental setup was used to obtain stress-strain diagrams from tensile tests at room temperature as well as several elevated temperatures. Furthermore, the specimens were subjected to short-time creep tests at various temperatures. Stress levels for creep testing were established as a percentage of yield stress. The results indicate that at lowered temperatures and lower stress levels, AISI 304 stainless steel can be used as a sufficiently creep resistant material.     

油田钻井废水的物化组合处理技术

对化学混凝-膜分离、化学混凝-活性碳吸附组合工艺处理油田钻井废水进行了试验研究。通过对4种混凝剂混凝对比试验，确定最佳混凝剂为聚合氯化铁(PFC)。在pH=8.1，助凝剂聚丙烯酰胺(PAM，质量分数0.5%)投加量w(PAM)为10mL·L^-1，PFC(质量分数10%)投加量w(KC-87)为10mL·L^-1的条件下，化学需氧量（COD）去除率达95.3%。混凝出水经膜分离深度处理后，没有达到排放要求。混凝出水经活性炭深度处理获得了较好的效果。在选取的4种活性炭中，KC-87粉末状果壳活性炭的吸附效果最好，在吸附时间为1h、投加量w(KC-87)为3g·L^-1的条件下，可使混凝出水中COD的去除率达75.3%。经PFC化学混凝和KC-87活性炭吸附组合工艺处理后，废水COD总去除率达到97.4%，其他污染物也得到了明显的去除，使得最终出水达到了国家废水综合排放标准一级水平。     

Supramolecular dendritic liquid quasicrystals

A large number of synthetic and natural compounds self-organize into bulk phases exhibiting periodicities on the 10(-8)-10(-6) metre scale as a consequence of their molecular shape, degree of amphiphilic character and, often, the presence of additional non-covalent interactions. Such phases are found in lyotropic systems (for example, lipid-water, soap-water), in a range of block copolymers and in thermotropic (solvent-free) liquid crystals. The resulting periodicity can be one-dimensional (lamellar phases), two-dimensional (columnar phases) or three dimensional ('micellar' or 'bicontinuous' phases). All such two- and three-dimensional structures identified to date obey the rules of crystallography and their symmetry can be described, respectively, by one of the 17 plane groups or 230 space groups. The 'micellar' phases have crystallographic counterparts in transition-metal alloys, where just one metal atom is equivalent to a 10(3)-10(4)-atom micelle. However, some metal alloys are known to defy the rules of crystallography and form so-called quasicrystals, which have rotational symmetry other than the allowed two-, three-, four- or six-fold symmetry. Here we show that such quasiperiodic structures can also exist in the scaled-up micellar phases, representing a new mode of organization in soft matter.