A novel application of the FPM to the buckling differential equation of non-uniform beams

In this study the buckling load (P) of non-uniform, deterministic and stochastically heterogeneous beams, is found by applying the Functional Perturbation Method (FPM) directly to the Buckling (eigenvalue) Differential Equation (BDE). The FPM is based on considering the unknown P and the transverse deflection (W) as functionals of heterogeneity, i.e., the elastic bending stiffness “K” (or the compliance S=1/K). The BDE is expanded functionally, yielding a set of successive differential equations for each order of the (Frèchet) functional derivatives of P and W. The obtained differential equations differ only in their RHS, and therefore a single modified Green function is needed for solving all orders. Consequently, an approximated value for the buckling load is obtained for any given morphology. Four examples of simply supported columns are solved and discussed. In the first three, deterministic realizations of K are considered, whereas in the fourth, K is assumed to be the stochastic field. The results are compared with solutions found in the literature for validation.     

苏里格气田“十三五”期间提高采收率技术思路

鄂尔多斯盆地苏里格气田的勘探与开发成果推动我国致密砂岩气产量实现了质的飞跃,如何提高采收率乃是其最核心的研究主题。为此,回顾了该气田的开发历程,着重阐述了提高单井产量技术进展,探讨了转变传统开发方式和提高采收率的技术思路与对策。研究结果表明:特大型致密砂岩气藏的评价、上产、稳产所需要的开发技术是呈"渐进式变化"的;基于甜点区筛选的井位部署技术、水平井开发技术、井型井网优化技术、快速钻井技术、储层改造技术和排水采气新工艺、"一体化"建设模式等支撑了该气田的快速上产。在此基础上,提出了"十三五"期间提高采收率的技术思路:①基于单井全生命周期分析的气田开发规划评价技术;②以提高采收率为目标的混合井网动态评价及加密技术;③集群化多井型多层系面积井网新区一次成型提高采收率技术;④基于风险和效益评价的储量评价模型;⑤"多维矩阵"式气井精细管理技术;⑥低产低效井挖潜技术;⑦新型井场环保技术;⑧基于一体化集成装置的地面工艺;⑨C_3~+混合烃类回收利用技术。以期为该区"十三五"期间致密砂岩气藏的开发提供更可靠的技术支撑。     

Heterogeneity of Adsorption Sites and Adsorption Kinetics of n-Hexane on Metal-Organic Framework MIL-101(Cr)

abstract The heterogeneity of adsorption sites and adsorption kinetics of n-hexane on a chromium terephthalate-based metal-organic framework MIL-101(Cr) were studied by gravimetric method and temperatu...     

Structural anisotropy of amorphous alloys with creep-induced magnetic anisotropy

Amorphous ribbons of different composition were annealed under tensile stress. This yielded a creep-induced magnetic anisotropy with an easy magnetic plane perpendicular to, or an easy axis parallel to, the ribbon direction, depending on the alloy composition. X-ray diffraction experiments and simple thermal expansion measurements show that the stress-annealed samples reveal a structural anisotropy which is released by post-annealing as a residual strain. This strain increases with the annealing stress and is therefore correlated with the induced magnetic anisotropy. The origin of this frozen-in strain is discussed in terms of structural heterogeneity in the strength of local atomic bonds. It is suggested that the induced magnetic anisotropy is related to the local magneto-elastic coupling in regions with strong bonding forces.     

试论致密砂岩气藏中的夹层控气作用——以川西大邑须家河组气藏为例

夹层主要是指储层内部不渗透或低渗透,能够对油气的流动、运移或聚集产生控制作用的条带。在天然气运移过程中,若夹层的毛细管突破压力小于下部储层的毛细管饱和压力,天然气会在下部储层还未达到含气饱和的时候通过夹层向上部储层运移,造成下部储层含有可动水。夹层与储层相互叠置会形成多个不饱和含气储层。此类气藏要形成纯气藏的重要因素是圈闭足够高大,进而增加气对原始地层水的排驱压力。大邑地区须家河组储层致密,非均质性强,须二段及须三段均含有不等厚致密夹层,气藏高度大于圈闭高度,夹层控气作用造成大邑气藏无边底水、气水过渡带长、高含水饱和度、普遍气水同出、含气丰度偏低、地层压力接近常压等特点,在此基础上对大邑地区须家河组气、水分布规律进行初步分析。     

Random parameter models of interstate crash frequencies by severity,number of vehicles involved,collision and location type

A nine-year (1999–2007) continuous panel of crash histories on interstates in Washington State, USA, was used to estimate random parameter negative binomial (RPNB) models for various aggregations of crashes.     

曲流河沉积非均质性研究——以北一区断东"二三结合"试验区葡Ⅰ 2沉积单元为例

大庆油田曲流河沉积厚油层聚合物驱油后进一步提高采收率面临着含水高、剩余油高度分散等难点。为了准确描述剩余油分布特征,需要精细刻画曲流河沉积厚油层非均质性。本文以北一区断东“二三结合”试验区葡I2沉积单元为例,按照平面非均质性、层内非均质性两个方面对葡I 2单元非均质性进行了精细刻画。提出聚驱后厚油层非均质性的主要研究内容,即：平面上开展单砂体分布特征研究;层内开展对曲流河侧积夹层的定量描述。该研究成果不仅增加了储层非均质性研究的深度和精度,而且为精细刻画聚驱后剩余油分布特征奠定了地质基础。     

异质金属夹层板的动态抗撞性能研究

异质金属夹层板具有优越的性能(比刚度高、耐撞性好等),在航空、航天、汽车、船舶等领域得到了广泛应用.对异质金属夹层板进行了碰撞载荷作用下的性能研究,采用有限元数值模拟的方法对碰撞过程中不同截面参数夹层板的变形能进行数值求解计算,并利用响应面方法构建了夹层板的比吸能近似函数,从而得到截面参数对夹层板抗撞性能影响规律.研究发现,为了提高夹层板的抗撞能力,应在保证夹层板有足够强度的基础上,尽量减薄面板的厚度.     

Does proximity to neighbours affect germination of spores of non-proteolytic Clostridium botulinum?

It is recognised that inoculum size affects the rate and extent of bacterial spore germination. It has been proposed that this is due to spores interacting: molecules released from germinated spores trigger germination of dormant neighbours. This study investigated whether changes to the total number of spores in a system or proximity to other spores (local spore density) had a more significant effect on interaction between spores of non-proteolytic Clostridium botulinum strain Eklund 17B attached to defined areas of microscope slides. Both the number of spores attached to the slides and local spore density (number of spores per mm²) were varied by a factor of nine. Germination was observed microscopically at 15 °C for 8 h and the probability of, and time to, germination calculated from image analysis measurements. Statistical analysis revealed that the effect of total spore number on the probability of germination within 8 h was more significant than that of proximity to neighbours (local spore density); its influence on germination probability was approximately four-times greater. Total spore number had an even more significant affect on time to germination; it had a nine-fold greater influence than proximity to neighbours. The applied models provide a means to characterise, quantitatively, the effect of the total spore number on spore germination relative to the effect of proximity to neighbouring spores.     

变形介质低渗透气藏水平井产能分析

大量实验研究证实低渗透气藏中气体渗流需要克服启动压力梯度,同时气体渗流还要受应力敏感效应影响。针对变形介质低渗透气藏,利用保角变换等方法,考虑非均质性、压力敏感效应、启动压力梯度以及表皮效应等影响因素,推导出了水平井产量计算模型。研究表明,各种考虑影响因素对低渗透气藏水平井的产量影响呈近似线性变化关系;非均质性的影响程度最大,其垂向渗透率高将有利于水平井产量的提高。通过实例计算说明该模型产能预测结果的相对误差小。