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101.
G.Y. Sha F.C. Jiang D. Wang D.K. Liu and R.T.Department of Mechanical Engineering Harbin Engineering University Harbin ChinaShenyang National Laboratory for Materials Science Institute of Metal Research The Chinese Academy of Sciences Shenyang China 《金属学报(英文版)》2002,15(6):556-560
An experimental-numerical method for measuring dynamic crack propagating velocities under stress wave loading is established in this paper. The experiments of the three-point bend specimen are done on the improved Hopkinson bar. Deflection of loading point, dynamic load and instantaneous crack length are measured, then crack propagating velocities are calculated. Experiments on 40Cr steel show that the results given by this method have a good agreement with that obtained by the resistance fracture gage method. Therefore this method is feasible for measuring crack propagating velocities under high loading rate and will have wide application. 相似文献
102.
103.
网格研究及其开发环境* 总被引:5,自引:0,他引:5
探讨了网格研究的基础理论、核心问题、具体研究内容和难点;仿真是研究网格资源管理和调度问题的重要方法,分析和评价了目前主要仿真工具的特点及应用;GT3已经成为网格项目开发的主流工具,给出了建立GT3 Core网格服务开发平台的方法;介绍了基于CGSP(China Grid Support Platform)的网格开发环境.以期有助于网格的创新研究和应用开发. 相似文献
104.
The deposition of copper by cold gas dynamic spraying has attracted much interest in recent years due to the capability to
deposit low-porosity oxide-free coatings. However, it is generally found that as-deposited copper has a signicantly greater
hardness, and potentially lower ductility, than bulk material. In this article, copper was deposited by cold spraying using
helium as the driving gas at both 298 and 523 K. Evidence is presented indicating that the material sprayed at the lower temperature
exhibits a lower dislocation density throughout the grain structure than the material sprayed at the higher temperature. The
low stacking fault energy of copper restricts recovery during annealing, and thus microstructural changes during annealing
only proceed once recrystallization begins. The material sprayed at low temperature (with the low dislocation density) exhibited
recrystallization at annealing temperatures as low as 373 K with a corresponding reduction in hardness. However, the copper
sprayed with helium at 523 K was resistant to annealing at temperatures up to 473 K where the dislocations in the structure
prevented recrystallization. However, at higher temperatures, recrystallization did proceed (with corresponding reductions
in hardness). The fracture behavior of the copper that was cold sprayed with helium at 523 K, both in the as-sprayed condition
and following annealing, was measured and explained in terms of the annealing mechanisms proposed.
The original version of this paper was published in the CD ROM Thermal Spray Connects: Explore Its Surfacing Potential, International
Thermal Spray Conference, sponsored by DVS, ASM International, and HW International Institute of Welding, Basel, Switzerland,
May 2–4, 2005, DVS-Verlag GmbH, Düsseldorf, Germany. 相似文献
105.
Influence of initial textures on dynamic recrystallization and textures in AZ31 magnesium alloys 总被引:1,自引:0,他引:1
1 INTRODUCTIONMagnesiumisthelightestmetallicstructurema terialwithhighspecificstrengthandthereforeiswidelyusedinautomotive ,electronicsandaerospaceindustries[1,2 ] .However ,magnesiumoftenshowsinsufficientplasticityatroomtemperatureduetoitsHCPstructurewithlessindependentsystemsofbasalslip .Toenhanceformabilityofmagnesium ,ahigherdeformingtemperatureisusuallyusedwithtwopur poses .Thefirstistoactivatenewslipsystemsbesidesbasalslip ,sothatmorethanfiveindependentslipsystemscanbeprovided ,be… 相似文献
106.
变频开关电源Fuzzy-PID控制器的设计 总被引:1,自引:0,他引:1
针对感应式变频开关电源在对金属材料进行热处理过程中,负载的等效参数和谐振频率发生变化,而变频电源的输出频率不能及时调整和跟踪的问题,结合PID和Fuzzy控制技术的优点,设计Fuzzy-PID控制器对变频电源进行控制,在大偏差时用Fuzzy控制,在小偏差时用PID调节。Fuzzy-PID控制器以单片机8098为核心,采用SPWM专用芯片SA4828,实现变频开关电源的电压、电流双闭环控制,使变频电源不仅具有较快的动态响应、更小的超调,并且具有较高的稳态精度和频率跟踪控制特性。 相似文献
107.
本文简要阐述了北化院BCS01和上海院SLC-S两种国产气相聚乙烯浆液催化剂的性能、催化剂结构,在Unipol聚乙烯工业装置上应用结果,以及和进口同类催化剂UCAT-J的性能比较。 相似文献
108.
应用粘弹谱仪考察了不同摩尔质量的聚酯(PET、PBT、PBT/PET)的动态力学性能,结果表明摩尔质量增大将提高其模量,但亦导致结晶速度变慢,使测得的模量反而比摩尔质量较低的试样小. 相似文献
109.
110.
Brad Nicholson 《Ergonomics》2014,57(9):1353-1365
Situational awareness is recognised as an important factor in the performance of individuals and teams in dynamic decision-making (DDM) environments (Salmon et al. 2014). The present study was designed to investigate whether the scores on the WOMBAT? Situational Awareness and Stress Tolerance Test (Roscoe and North 1980) would predict the transfer of DDM performance from training under different levels of cognitive load to a novel situation. Participants practised a simulated firefighting task under either low or high conditions of cognitive load and then performed a (transfer) test in an alternative firefighting environment under an intermediate level of cognitive load. WOMBAT? test scores were a better predictor of DDM performance than scores on the Raven Matrices. Participants with high WOMBAT? scores performed better regardless of their training condition. Participants with recent gaming experience who practised under low cognitive load showed better practice phase performance but worse transfer performance than those who practised under high cognitive load.Practitioner Summary: The relationship between task experience, situational awareness ability, cognitive load and the transfer of dynamic decision-making (DDM) performance was investigated. Results showed that the WOMBAT? test predicted transfer of DDM performance regardless of task cognitive load. The effects of cognitive load on performance varied according to previous task-relevant experience. 相似文献