Effects of gage length, loading rates, and damage on the strength of PPTA fibers

Axial tension and transverse compression experiments on single fibers were performed to investigate the mechanical behavior of three high-performance fibers (Kevlar^®, Kevlar^® 129, and Twaron^®) with diameters in the order of 9-12 μm. The single fibers were manufactured from 1998 through 2008. A miniaturized tensile Kolsky bar was used to determine the tensile response of PPTA single fibers at a high strain rate. Gage length and strain rate were found to have minimum effects on the tensile strength of PPTA single fibers. Manufacturing time over a decade was found to have negligible effects on the tensile strength of the fibers. Initial transverse compression on the fibers reduces their ultimate tensile strengths. A high resolution scanning electron microscope (SEM) was also used to examine the fracture modes of transversely deformed fibers. Different types of fracture morphology were observed.     

ScalaTrace: Scalable compression and replay of communication traces for high-performance computing

Characterizing the communication behavior of large-scale applications is a difficult and costly task due to code/system complexity and long execution times. While many tools to study this behavior have been developed, these approaches either aggregate information in a lossy way through high-level statistics or produce huge trace files that are hard to handle.     

高效能单相异步发电机

本文根据单相异步发电机有负载、励磁和调磁三项功能系统的实际情况,较全面地分析了如何协调它们,合理设计以获得性能优异的单相异步发电机。     

A high-performance distributed algorithm for mining association rules

We present a new distributed association rule mining (D-ARM) algorithm that demonstrates superlinear speed-up with the number of computing nodes. The algorithm is the first D-ARM algorithm to perform a single scan over the database. As such, its performance is unmatched by any previous algorithm. Scale-up experiments over standard synthetic benchmarks demonstrate stable run time regardless of the number of computers. Theoretical analysis reveals a tighter bound on error probability than the one shown in the corresponding sequential algorithm. As a result of this tighter bound and by utilizing the combined memory of several computers, the algorithm generates far fewer candidates than comparable sequential algorithms—the same order of magnitude as the optimum.     

Optimization of selected chromatographic responses using a designed experiment at the fine-tuning stage in reversed-phase high-performance liquid chromatographic method development

This study evaluated the applicability of a designed experiment at the fine-tuning stage in reversed-phase high-performance liquid chromatographic (HPLC) method development. Using acetaminophen, theophylline, and caffeine as model drugs, a 3² factorial design was used to optimize selected chromatographic responses. The effects of the ratio of water to acetonitrile (%v/v) in the mobile phase and mobile phase flow rate on the theoretical plate number of acetaminophen peak, capacity factor of acetaminophen, resolution of acetaminophen and theophylline peaks, and the time for the elution of last peak (run time) were determined. Polynomial equations were derived to evaluate the quantitative relationships between the experimental factors and responses. A solution space was found by overlaying contour plots. Results indicated that, once the mobile phase that provides reasonably good retention and resolution has been identified, the strategy of using a designed experiment is advantageous over the conventional one-factor-at-a time approach since it would enable the analyst to optimize important responses, including run time with a minimum number of experiments.     

A high-performance computing method for data allocation in distributed database systems

Enhancing the performance of the DDBs (Distributed Database system) can be done by speeding up the computation of the data allocation, leading to higher speed allocation decisions and resulting in smaller data redundancy and shorter processing time. This paper deals with an integrated method for grouping the distributed sites into clusters and customizing the database fragments allocation to the clusters and their sites. We design a high speed clustering and allocating method to determine which fragments would be allocated to which cluster and site so as to maintain data availability and a constant systemic reliability, and evaluate the performance achieved by this method and demonstrate its efficiency by means of tabular and graphical representation. We tested our method over different network sites and found it reduces the data transferred between the sites during the execution time, minimizes the communication cost needed for processing applications, and handles the database queries and meets their future needs.     

高性能混凝土绝热温升影响因素的试验研究

通过混凝土绝热温升比对试验，探讨了初始温度、粉煤灰、水胶比等因素对混凝土绝热温升的影响。结果表明：混凝土拌和物的初始入模温度对早期的温升速率影响较明显，初始温度越高，温升速率越快，但对混凝土最终的绝热温升值影响很小；粉煤灰等量取代水泥可以使混凝土早期的温升速率减慢，放热峰值推迟出现，但对最终温升值影响很小；胶凝材料用量越多，其早期的温升速率越快，最终的温升值越高。     

Parallel partitioning for distributed systems using sequential assignment

This paper introduces a method to combine the advantages of both task parallelism and fine-grained co-design specialisation to achieve faster execution times than either method alone on distributed heterogeneous architectures. The method uses a novel mixed integer linear programming formalisation to assign code sections from parallel tasks to share computational components with the optimal trade-off between acceleration from component specialism and serialisation delay. The paper provides results for software benchmarks partitioned using the method and formal implementations of previous alternatives to demonstrate both the practical tractability of the linear programming approach and the increase in program acceleration potential deliverable.     

影响盐酸苯海拉明水溶液澄明度的原因剖析

利用高效液相色谱、红外光谱等分析测试手段，对盐酸苯海拉明中存在的各种杂质进行了全面剖析，并对各杂质含量进行了定量测定，阐述了影响产品水溶液澄明度的原因。这一剖析结果对产品的生产工艺及质量控制均有重要的指导意义。