某岸边工程事故原因分析及治理

滇池流域为高原湖相沉积地区,土层大部分为中高压缩性深厚软土,含水量较大,有机质含量较高,天然地基承载力、抗剪强度均较低,在此类岸边上的建(构)筑物,有时会出现不均匀沉降和岸坡失稳导致较大变形的问题。本文通过某桥台变形的治理,分析了产生这个问题的主要原因可能是由于岸边效应引起的,提出了在滇池的岸坡地区修建建(构)筑物应注意的岩土工程问题。     

榫卯：一种可组合的定制化内存分配框架

动态内存分配器是现代应用程序重要组成部分, 它负责管理空闲内存并处理用户内存请求. 现代通用动态内存分配器能够提供较为平衡的性能与内存利用率, 但考虑到不同应用场景的内存使用情况和优化目标不同, 使用通用内存分配器并非最优解. 针对应用场景定制的专用内存分配器通常能够更好地满足系统需要, 然而编写专用内存分配器较为费时, 也容易出错. 开发者通常使用内存分配框架搭建专用动态内存分配器. 然而, 现有的内存分配框架存在抽象能力较差, 组合性与定制性不足的问题. 为此, 从函数式编程视角审视动态内存分配过程, 基于函数可组合性提出了一种可组合的定制化动态内存分配器框架榫卯. 榫卯框架将系统内存分配抽象为多个互不耦合的内存分配层级函数的组合, 这些层级函数能够扩展出策略槽, 以提供更高的定制性和组合性. 榫卯框架基于标准C实现, 依赖C预处理器的元编程特性实现层级函数组合的零性能开销. 开发者能够通过组合与定制分配器的层级函数, 快速构建出适合应用场景的内存分配器. 为了证明榫卯框架的有效性, 使用榫卯框架构建了3种不同的内存分配器实例: tlsfcc, hslab与wfslab, 其中tlsfcc针对多核嵌入式应用场景, 通过替换同步策略优化并发吞吐率; hslab是核心感知的slab式分配器, 通过定制线程缓存优化在异构硬件的性能; wfslab是低延迟的无等待/无锁分配器. 为了评估这3种内存分配器实例, 通过运行基准测试对比现有内存分配器. 实验分别在8核x86/64平台和8核异构aarch64嵌入式平台进行. 实验表明tlsfcc与原始tlsf分配器相比, 在上述两个平台上分别取得了平均1.76和1.59的加速比; 对比hslab与类似架构的tcmalloc, 它在两个平台的平均执行时间仅为tcmalloc的69.6%和85.0%; wfslab则取得了参与实验对比的内存分配器中最小的最差情况内存请求延迟, 其中包括目前最先进的无锁内存分配器mimalloc和snmalloc.     

S Zorb装置再生器下料中断原因分析及处置

对中国石油化工股份有限公司九江分公司1.20 Mt/a S Zorb装置再生器下料中断原因进行了分析.提出了处置措施:加强原料和工艺精细化管理,确保汽油含水量维持最低水平;将再生器下料流程,从原设计的再生器锥体底部输送吸附剂至再生滑阀,改为再生器筒体下部斜管下料管线输送至再生滑阀,防止吸附剂结块堵塞管路;清理再生器底部...     

Approximate blocking probabilities in loss models with independence and distribution assumptions relaxed

Effective approximations are developed for the blocking probability in a general stationary loss model, where key independence and exponential-distribution assumptions are relaxed, giving special attention to dependence among successive service times, not studied before. The new approximations exploit recent heavy-traffic limits for the steady-state number of busy servers in the associated infinite-server model with the same arrival and service processes. In addition, a new heavy-traffic approximation is developed for the long-run proportion of time that all servers are busy. These new approximations are then combined to develop new approximations for the separate blocking probabilities of individual arrival streams in multi-class loss models. Simulation experiments show that these approximations are effective.     

连续操作状态下结晶器内颗粒悬浮状态的研究

使用计算流体力学的方法,在连续操作状态下,模拟研究结晶器内晶体悬浮状态.重点考察在不同搅拌速度下,不同粒径的晶体在结晶器内的混合状态和分布与排料位置的关系.对在容积为10,L的DTB结晶器进行模拟.结果表明,晶体的粒径和搅拌速度对混合状态有很大的影响,而排料口的高度则对结晶器的混合状态无明显影响.     

空分设备主换热器增压通道冰堵故障分析及处理

由于膨胀机增压端后冷却器内漏,30000 m3/h空分设备在临时停车再开车时出现了主换热器增压通道阻力增大现象。采取临时停车对增压通道进行局部加温的方法未能排除故障,后启动空压机,对主换热器部位进行加温解冻才解决问题。简介主换热器增压通道冰堵后的参数变化情况,介绍堵塞通道解冻的具体过程。     

混料区组设计

本文介绍了混料区组设计的概念及其拟合二阶Ｓｃｈｅｆｆｅ模型的对称单纯形区组设计方法。     

A Non-Blocking Buffer Mechanism for Real-Time Event Message Communication

It is desirable to facilitate data communications among concurrent computation threads without incurring non-essential synchronizations in real-time computing systems. An interaction mechanism, called the non-blocking writer (NBW) mechanism and invented by Kopetz, is useful in facilitating state message communication from a producer to a consumer thread in real-time applications. A more widely applicable practical interaction mechanism called the non-blocking buffer (NBB) is presented here. The NBB mechanism can be viewed as a significant extension of the NBW mechanism. The NBB mechanism facilitates communication of event messages from a producer to a consumer without causing any party to experience blocking. Therefore, its application scope includes all conceivable producer-consumer situations. The NBB mechanism is not a replacement of but rather a companion to the NBW mechanism since the latter facilitates the most efficient state message communication. The application of NBBs in building middleware supporting real-time objects is discussed as a demonstration of the utility of the NBB mechanism.     

Overdependence on degraded gist memory in Alzheimer's disease.

Alzheimer's disease (AD) reduces associative effects on false recognition in the Deese-Roediger-McDermott task, either due to impaired memory for gist or impaired use of gist in memory decisions. Gist processes were manipulated by blocking or mixing studied words according to their associations and by varying the associative strength between studied and nonstudied words at test. Both associative blocking and associative strength had smaller effects on false recognition in AD patients than in control participants, consistent with gist memory impairments. However, unlike the case with control participants, blocking influenced true and false recognition equally in AD patients, demonstrating an overdependence on gist when making memory decisions. AD also impaired item-specific recollections, relative to control participants, as true recognition of studied words was reduced even when the two groups were equated on gist-based false recognition. We propose that the overdependence on degraded gist memory in AD is caused by even larger impairments in item-specific recollections. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

呼损率计算对步进式带宽分配性能的影响

在对电信网虚路径的带宽分配算法的研究中,罗茂松等人提出了一种单虚路径条件下的带宽分配算法,与典型的“二分法”相比,其优点是误差小,运算速度快,其缺点是运行时间起伏波动大。本文在步进式最优算法的基础上,结合计算呼叫损失概率(CBP)的单虚路径近似算法,给出步进式最优带宽分配的快速算法。此快速算法与原有步进式算法相比较,运算速度明显加快,并克服了步进式算法运行时间起伏波动大的缺点。