Mn对Fe_3Al合金室温力学性能的影响

Ｍｎ对Ｆｅ_３Ａｌ合金室温力学性能的影响楼白杨，刘茂森，毛志远，涂江平，肖延龄，钟映宏（浙江大学）Ｆｅ３Ａｌ金属间化合物具有抗氧化耐腐蚀性良、比强度高和成本低等特点［１，２］，从而具有可观的工程应用前景。对这种材料目前国内研究的热点之一是改善其室温塑?..     

Suppression of carbon monoxide formation in oxide-coated TZM molybdenum X-ray rotating anodes

Higher performance designs for rotating anode X-ray tubes have increased the average rotating anode temperature from below 1100 °C to well above 1300 °C. This temperature increase has accelerated the formation of carbon monoxide by reaction of carbon from the alloy substrate with oxygen from the emissive coating. The dominant carbon source is thought to be Mo₂C grain boundary precipitates in the TZM molybdenum alloy substrate. The dominant oxygen source is thought to be TiO in the emissive coating. Placement of a monocarbide-forming reactive layer between the alloy substrate and the emissive coating has been demonstrated to lower the thermodynamic activity of the carbon source and dramatically reduce the rate of formation of carbon monoxide.     

铸造多晶硅中氧的热处理行为研究

研究了铸造多晶硅中不同温度单步退火下氧沉淀的形成规律。实验发现，单步热处理工艺下铸造多晶硅中氧沉淀的形成规律和单晶硅的基本相似，但是在铸造多晶硅中形成氧沉淀的量明显高于直拉单晶硅中氧沉淀的量；在含高密度位错的单晶硅中形成氧沉淀的量远高于无位错单晶硅中氧沉淀的生成量，而有晶界的多晶硅中形成氧沉淀生成量仅稍微高于无晶界单晶硅中氧沉淀生成量。以上结果表明，铸造多晶硅中位错对氧沉淀的形成有明显的促进作用，而晶界则对氧沉淀的促进作用不是很显著。最后，基于实验结果讨论了铸造多晶硅中初始氧浓度，位错和晶界对氧沉淀影响的机理。     

钢铬钛共渗工艺的研究

对工业纯铁、45钢和3Cr2W8V钢的低真空铬钛共渗进行了研究,探讨了共渗层的组织结构、生长过程以及温度、时间等工艺因素的影响。     

Secure three-party computational protocols for triangle area

In this work, we have put forth two different protocols to address a concrete secure multi-party computational (MPC) problem related to a triangle, of which the coordinates of the three vertices are confidentially kept by the three participants, respectively. The three parties wish to collaboratively compute the area of this triangle while preserving their own coordinate privacy. As one of the merits, our protocols employ weaker assumptions of the existence of pseudorandom generators. In particular, unlike massive secure MPC protocols that rely a lot on oblivious transfer, ours utilize a new computing idea called “pseudorandom-then-rounding” method to avoid this burdensome obstacle. The two protocols are based on different theorems, while they both make use of the same underlying idea. At last, we provide a detailed proof for the first protocol by a series of security reductions of our newly defined games, which seems somewhat stronger than the previous simulation-based proofs and a proof sketch for the second one. Analysis and discussion about the reasons are provided as well to round off our work.     

模块主成分分析在人脸重建中的应用

模块主成分分析是人脸重建中一种重要的子空间学习方法,鲁棒性不足是传统的基于L2范数的模块主成分分析(BPCA-L2)的主要问题。为此,提出了一种新的基于L1范数的模块主成分分析(BPCA-L1)方法。该方法使用了对奇异值不太敏感的L1范数。基于L1范数的模块主成分分析方法简单并易于实现,在一些人脸数据集上的重建实验验证了其有效性。     

Improving MapReduce Performance with Partial Speculative Execution

The MapReduce framework has become the de facto standard for big data processing due to its attractive features and abilities. One is that it automatically parallelizes a job into multiple tasks and transparently handles task execution on a large cluster of commodity machines. The increasing heterogeneity of distributed environments may result in a few straggling tasks, which prolong job completion. Speculative execution is proposed to mitigate stragglers. However, the existing speculative execution mechanism could not work efficiently as many speculative tasks are still slower than their original tasks. In this paper, we explore an approach to increase the efficiency of speculative execution, and further improve MapReduce performance. We propose the Partial Speculative Execution (PSE) strategy to make speculative tasks start from the checkpoint. By leveraging the checkpoint of original tasks, PSE can eliminate the costs of re-reading, re-copying, and re-computing the processed data. We implement PSE in Hadoop, and evaluate its performance in terms of job completion time and the efficiency of speculative execution under several kinds of classical workloads. Experimental results show that, in heterogeneous environments with stragglers, PSE completes jobs 56 % faster than that with no speculation and 12 % faster than that with LATE, an improved speculative execution algorithm. In addition, on average PSE can improve the efficiency of speculative execution by 24 % compared to LATE.     

基于VB技术开发学校电教管理系统

对区域性的学校电教管理系统的开发做了详细阐述,并提出了详细的解决方案。     

Characterising effective eLearning resources

The widespread availability of digital learning resources in a variety of media formats offers the possibility to make a profound difference in education. This potential has not been fully realised for range of interrelated reasons. In this paper we study the key characteristics of learning resources that have proved effective in changing learning and teaching, and relate them to existing frameworks for understanding resources. We outline the relationships between resources, their users, and the way they are used, and explore issues that influence practitioners in choosing a particular resource. Our study is based on a review of resources for e-learning and chemistry in post-compulsory education, undertaken for the UK Joint Information Systems Committees (JISC), as part of a wider study examining ‘The Effectiveness of Resources, Tools and Support Services used by Tutors in Designing and Delivering E-Learning Activities’.     

基于J2EE的O/R(Object-Relation)映射方案研究

对象模型和关系模型是两种完全不同的模式,在开发中如何实现对象到关系的映射是一个关键的问题,分析了对象关系映射不匹配的各个方面,以及当前的各种持久化解决方案,并重点分析了透明对象关系映射的特点,最后对如何实现对象关系映射的关键技术进行了研究.