Energy-Aware Fault-Tolerant Dynamic Task Scheduling Scheme for Virtualized Cloud Data Centers

Mobile Networks and Applications - As clouds have been implemented and widely used in various fields, both the size and the number of cloud data centers (CDCs) are growing rapidly. Serious problems...     

Research of network data mining based on reliability source under big data environment

In the era of big data, facing vast amounts of network data, only identifying the reliable data source can the researchers extract the original data that can be used in scientific research. Building reliable network data mining model based on the improvement of PageRank algorithm with applying each improved algorithm. Then the model is divided into three modules: the first, use PageRank and TrustRank to eliminate cheating webpages; then, refine webpages which related to research topic highly by TC-PageRank which combined with the topic relevancy between webpages and weight of time difference; finally, determine the authoritative webpages of the original data source by the improved HITS which considered the influence of the similarity between webpage and research topic and the amplification of webpage links to the authoritative webpages. Meanwhile, the partitioning of matrix operation based on MapReduce reduces the time and space complexity of the algorithms. And the feasibility and accuracy of the method are verified by comparative analysis of the algorithms.

     

疲劳短裂纹的损伤特征和计算机模拟

对一种焊接用低碳钢的实验研究表明，疲劳短裂纹萌生了铁素体晶粒区域的滑移带，短裂纹数密度随疲劳周次不断增加，短裂纹的取向与所在铁素体晶粒的滑移位向相关。以所观察到的短裂纹特征为背景，用计算机模拟短裂纹萌生，扩展，汇合的演化过程，模拟结果显示，短裂纹损伤导致断裂的临界指数具有很宽的分布带，面裂纹路径具有较稳定的分维数值。     

基于GUI的数字信号处理课程演示系统研究

Matlab中的Guide是专用于图形用户界面的快速开发环境,利用该工具编程开发的数字信号处理课程演示系统,完成了用户登录界面、系统选择主界面和两个内容子模块界面的设计和编程。其中,在两个内容子模块中开发了常用典型序列的产生、基本运算、离散线性时不变系统、时域离散傅里叶变换、离散傅里叶级数、离散傅里叶变换、DFT和FFT的应用、滤波器的设计和语音信号处理等Matlab辅助分析与设计实验,该系统直观且形象,界面美观大方。     

Influence of processing parameters of selective laser melting on high‐cycle and very‐high‐cycle fatigue behaviour of Ti‐6Al‐4V

Orthogonal experiment design together with the analysis of variance was used to examine the processing parameters (laser power, scan speed, layer thickness and hatch spacing) of selective laser melting (SLM) for superior properties of SLM parts, in which nine groups of specimens of Ti‐6Al‐4V were fabricated. The results clarify that the influence sequence of individual parameter on the porosity is laser power > hatch spacing > layer thickness > scan speed. Ultrasonic fatigue tests (20 kHz) were conducted for the SLMed specimens in high‐cycle fatigue (HCF) and very‐high‐cycle fatigue (VHCF) regimes. The S‐N data show that the fatigue strength is greatly affected by the porosity: the group with the smallest porosity percentage having the highest fatigue strength in HCF and VHCF regimes. Then, the tests on the validation group were performed to verify the optimal combination of SLM processing parameters. Moreover, the observations by scanning electron microscopy revealed that fatigue cracks initiate at lack‐of‐fusion defects in the cases of surface and internal crack initiation.     

单细胞蛋白的发展动向与前景

本文对生产的单细胞的原料路线、微生物种类、国内外生产单细胞的技术发展动向进行了比较详细的介绍，同时对国内外市场前景作了预测，为我国发展这一技术提出了建议。     

Synthesis of ZnO nanorods and their optical absorption in visible-light region

Single crystalline ZnO nanorods were prepared by the hydrothermal method with synthesized ZnCl2·4Zn(OH)2 as the precursor. Morphologies of the nanorods were controlled by various reaction conditions with cetyltrimethylammo-nium bromide (CTAB) as the modifying agent. The nanorods were characterized by XRD, TEM, UV-Vis spectra, and IR spectra. The microstructure of holes in nanosize was observed on the surface of the nanorods. The UV-Vis spectra indicate that the as-prepared ZnO nanorods have absorption of visible-light as well as ultraviolet-light. Therefore, these nanorods may be good candidates for visible-light photocatalysis materials from the viewpoint of practical applications. The reason for visible-light absorption was discussed in this article.     

Crack growth rates and microstructure feature of initiation region for very‐high‐cycle fatigue of a high‐strength steel

The S‐N data up to very‐high‐cycle fatigue (VHCF) regime for a high‐strength steel were obtained by fatigue tests under constant amplitude and variable amplitude (VA) via rotating bending and electromagnetic resonance cycling. Crack initiation for VHCF was from the interior of specimens, and the initiation region was carefully examined by scanning electron microscopy and transmission electron microscopy. Crack growth traces in the initiation region of fine‐granular‐area (FGA) were the first time captured for the specimens under VA cycling by rotating bending. The obtained crack growth rates in FGA were upwards to connect well with those in fish‐eye region available in the literature and were associated well with the calculated equivalent crack growth rates in FGA. The observations of profile samples revealed that FGA is a nanograin layer for the specimens under VA cycling, which is a new evidence to support the previously proposed “numerous cyclic pressing” model.     

南京地区实施油,化,纤一体化的优越性与必要性

论述了南京地区实施油，化、纤一体化的必要性。     

一种等应力试样中的疲劳短裂纹行为

设计了一种三角形试样,当施加弯曲载荷时,该试样等腰三角形段内的表面拉应力为常数。采用振动试验机对所设计的试样进行疲劳试验,以研究一种焊接金属表面疲劳短裂纹萌生和发展特征。结果表明,疲劳短裂纹起源于铁素体晶内的滑移带。随疲劳周次增加,短裂纹发展以裂纹密度不断增加为主要特征。短裂纹的汇合造成裂纹发展且裂纹路径以穿晶为主。