On the coordinator's rule for Fast Paxos

Fast Paxos is an algorithm for consensus that works by a succession of rounds, where each round tries to decide a value v that is consistent with all past rounds. Rounds are started by a coordinator process and consistency is guaranteed by the rule used by this process for the selection of v and by the properties of process sets called quorums. We show a simplified version of this rule for the specific case where the quorums are defined by the cardinality of these process sets. This rule is of special interest for implementors of the algorithm.     

示波冲击试验在螺旋埋弧焊管检验上的应用

针对管线钢在夏比冲击试验中容易出现的问题,结合示波冲击试验的特点,提出了采用示波冲击试验对螺旋焊管的焊缝和母材进行韧性分析,远比普通冲击试验机更能够反映材料韧性的真实情况,指出了在管线钢韧性试验中应用示波冲击试验的必要性。     

东营凹陷胜坨地区沙四段地层压力特征及其对储层的影响

选择声波时差资料,根据等效深度法计算了东营凹陷胜坨地区沙四段地层压力,结合实测压力分析了该层段地层压力特征及其对储层的影响.胜坨地区沙四段埋深大于3 000m的地层普遍存在超压,压力系数为1.2～1.8.在平面上,胜北断层上升盘沙四段为正常压力,超压主要分布在胜北断层下降盘,并且向凹陷中心压力系数逐渐增大.胜坨地区沙四段超压对储层具有良好的保护和改善作用.超压抑制了压实作用,有利于原生孔隙和已形成的次生孔隙的保存;超压形成过程中有机质演化和粘土矿物转化释放的大量有机酸和二氧化碳促进了不稳定矿物的溶解,形成了次生孔隙;由于超压作用,胜坨地区沙四段储层中普遍发育网络状、炸裂状超压裂缝,有效地改善了储层的渗透能力.     

On the reaction pathway for the formation of benzene from acetylene catalyzed by palladium

The reaction between gas‐phase acetylene and alumina‐supported palladium saturated with ¹³C‐labelled vinylidene is studied using both one‐pulse, ¹³C magic‐angle spinning, nuclear magnetic resonance (NMR) spectroscopy and by mass spectroscopic analysis of the reaction products to probe the reaction pathway. The presence of vinylidene on alumina‐supported palladium is confirmed by comparing the infrared spectra of the species formed on the supported sample with those found on a Pd(111) single crystal. It is shown using NMR that a high pressure (∼350 Torr) of gas‐phase acetylene reacts with adsorbed vinylidene at the same rate at which benzene is formed catalytically on the same sample. The resulting benzene incorporates two ¹³C atoms. This indicates that benzene is formed by a slow reaction between gas‐phase (¹²C‐labelled) acetylene and adsorbed vinylidene (¹³CH₂=¹³C=) to form a C₄ intermediate which reacts rapidly with further acetylene to yield benzene. There are precedents for such reactions in homogeneous phase. The proposed reaction pathway differs from that elucidated previously from ultrahigh vacuum studies on clean Pd(111), where it was found that benzene synthesis also proceeds via a C₄ intermediate, in this case formed from two adsorbed acetylenes. This revised version was published online in July 2006 with corrections to the Cover Date.     

长江下游三沙（福姜沙、通州沙、白苑沙）水道演变分析及深水航道整治设想

长江下游三沙（福姜沙、通州沙、白茆沙）水道是长江口以上重要的碍航线段，随着长沙口深水航道治理工程的实施，有效地发挥长黄金水道的效益，对三沙水道的治理势在必行。本文结合水流泥沙运动特性，探讨三沙水道河床演变的主要影响因素以及对航道的影响，并提出三沙水道海轮深水航道整治初步设想。     

Loss of the thalamic nuclei for "head direction" impairs performance on spatial memory tasks in rats.

This study sought to characterize the effects of removing the nuclei of primary importance in relaying the thalamic head direction signal to the hippocampal formation (the anterior dorsal [AD] and lateral dorsal [LD] nuclei) on the performance of a variety of spatial and nonspatial tasks. The results indicate that combined excitotoxic lesions of the AD and LD nuclei produce marked deficits on a variety of spatial tasks. These tasks included T-maze alternation and the ability to locate a hidden platform set at a fixed distance and fixed direction from a beacon in a Morris water maze. Although object recognition appeared unaffected, marked impairments were found in the ability to detect when an object was placed in a novel position (object-in-place memory). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

桩120块油层伤害评价及增产措施优化

针对1992年投产的桩120块10口井投产未成功,而酸化成功率仅为22%,压裂3口井均失败的实际情况,以该块桩120-3取心井油层岩心为基础,采用静态分析和动态模拟相结合、室内研究与现场试验相结合的方法,完成了油层速敏性、盐敏性、水敏性、酸敏性室内实验及评价,确定出桩120块沙二段油层改造时,影响最大的因素是酸敏性,速敏、盐敏、水敏都是影响油层改造效果的次要因素.进一步对两种主要酸化配方(盐酸、土酸)和两种新的解堵剂(HBF-5、SCP-1)的理化性质及配伍性进行了室内模拟研究,评价了施工液体系及其对储层的处理效果,优化出预防伤害和解除伤害的有效措施为:采用低浓度的盐酸(浓度3%),或适当浓度的中强酸及弱酸深部处理,采用SLP-1解除酸化造成的二次伤害及配套措施.根据室内研究结果,对桩120块5口油井、1口水井进行施工处理,5口油井由处理前的不产油增至单井平均日产油16.7t的良好效果,1口水井由60m³/d增注到120m³/d.     

松辽盆地东岭地区幕式成藏分析

油气运聚期次、成熟度分析是一项非常有价值的研究工作。利用有机包裹体测温和包裹体中烃类组成特征、结合盆地模拟技术的精细时-温埋藏史、古地温史恢复来研究油气运聚期次、成熟度,可有效地指明成藏史。作者对松辽盆地南部东岭地区有机包裹体测温和包裹体中烃类组成的研究表明,油气运聚具有3期幕式成藏的特点:第一期为85.8Ma(姚家组沉积末期);第二期为78.6Ma(嫩江组沉积末期);第三期为66Ma(明水组沉积末期)。由于有机包裹体丰度及有机组分含量较低,加之后期构造破坏,不利于现今的油气勘探。      

Hydration reaction of tricalciumaluminate in different systems

The hydration behaviour of tricalciumaluminate in excess magnesium sulfate solution (0.05 molar) in various systems was investigated. The effect of gypsum, gypsum + lime, gypsum + lime + alite on the hydration reaction of tricalciumaluminate at room temperature was studied. The hydration process was carried out in an excess amount of magnesium sulfate solution, and it was followed for a various time intervals up to 7 days. The results obtained from XRD analysis and solution composition have revealed that magnesium sulfate solution (0.05 molar) retards the hydration reaction and prevents the ettringite formation as a result of decreasing alkalinity of the reaction medium.     

川中地区中三叠统雷口坡组构造特征及解释方法探讨

通过对川中龙女寺地区的地质、测井、地震资料的综合分析,探讨了该区中三叠统雷口坡组的构造特征,即 在雷口坡组和下伏嘉陵江组的盐岩和膏岩等柔软地层的盐底辟构造作用及区域上的挤压构造作用共同影响下, 龙女寺地区雷口坡组形成了以坡坪式逆冲断层为主,密集的低幅度断弯褶皱相伴生的构造特征。当难以直接对 雷一2顶界反射对比时,可以选择同一组硬地层--雷一1亚段与雷三1至雷一2亚段的地震反射间的平行和亚 平行关系作为识别目的层位的辅助层。