We have used the event generator LUCIAE to analyse the data of singly strange particle production in pp,pS,and SS reactions at 200AGeV.The results seem to indicate that in comparing with the pp and the pS minimum bias event,the SS center collision seems having stronger final state interaction,shorter fomation time of strange particles,and larger s quark pair suppression factor.The strangeness enhancement evidence from pp to pS and to SS could be explained without the introduction of quark-gluon plasma formation. 相似文献
通过改变硅源和晶化时间的方法,采用水热法合成了系列SAPO-5分子筛材料,用X光衍射(XRD)和27Al MAS NMR对产物的晶相结构进行表征,用13C CP MAS NMR研究了不同阶段的产物中模板剂的存在状态。结果可见:以SiO2凝胶为硅源时;薄水铝石反应物有较高的活性,在48h的晶化时间内,延长晶化时间有助于SAPO-5分子筛的完整结晶,当晶化时间超过48h时,其中已形成的SAPO-5的结构部分被破坏,并转化为SAPO-34.且SAPO-34的量随晶化时间的延长而增多。当以Si(OEt)4为硅源时,铝反应物的反应活性较低,在72h的晶化时间范围内,延长晶化时间有助于SAPO-5产物的形成,使其结构愈加完整,在SAPO-5分子筛的形成过程中,模板剂的状态随分子筛结构的变化而变化,由于三乙胺(Et3N)模板剂中的甲基和亚甲基所处位置不同,其弛豫时间受分子筛结构的影响较大,可用其中甲基的13C MAS NMR诺线的强度及化学位移来表示分子筛结构的完整性。 相似文献
Summary: The morphology and tensile deformation behaviour of a highly asymmetric styrene/butadiene star block copolymer (polystyrene (PS) content = 74%) containing random PS‐co‐PB (polybutadiene) copolymer as a rubbery phase were investigated. The existence of double yielding, similar to that observed in some semicrystalline polymers, was detected in this nanostructured amorphous polymer. The observed phenomenon may be correlated with two different micromechanical processes taking place at the initial stage of deformation.
The stress‐strain curve of the star block copolymer prepared here (each curve represents a different method). The two yield points are clearly visible (labelled I and II). 相似文献
Investigating the minimum weight triangulation of a point set with constraint is an important approach for seeking the ultimate solution of the minimum weight triangulation problem. In this paper, we consider the minimum weight triangulation of a sparse point set, and present an O(n4) algorithm to compute a triangulation of such a set. The property of sparse point set can be converted into a new sufficient condition for finding subgraphs of the minimum weight triangulation. A special point set is exhibited to show that our new subgraph of minimum weight triangulation cannot be found by any currently known methods. 相似文献