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31.
The effects of α and β phase interactions on the room-temperature tensile and creep deformation behavior of α + β titanium
alloys with Widmanst?tten microstructures were studied using Ti-6.0 wt pct Mn and Ti-8.1 wt pct V as the model two-phase alloy
systems. This article, Part I, deals with tensile deformation. It was found that when the α phase is present as thin (<10-μm)
plates in the α + β alloys, significant twinning occurs. No significant twinning was observed in single-phase alloys with
the same chemistry and similar grain size. Additionally, the β phase of Ti-8.1 V deforms by stress-induced hexagonal martensite
(α′), while only twinning occurs in the single-phase β alloy with the same chemistry. Twinning in the α phase in association
with stress-induced martensite (SIM) in the β phase was observed for the first time in a two-phase titanium alloy. This behavior
is explained in terms of a number of factors including elastic interaction stresses between the α and β phases, coherency
between the α phase and hexagonal martensite, and β phase stability. 相似文献
32.
33.
P. Cofta 《BT Technology Journal》2006,24(2):214-218
Trust is the key element of commerce, both for traditional models and — more recently — for eCommerce. Unlike its traditional
counterpart, eCommerce relies on trust being created and maintained with the help of digital devices and services. Convergence
brings significant changes to the way people interact through digital media by offering ubiquitous and seamless communication.
This has a significant impact on the way trust is established and maintained, with consequent impact upon eCommerce. This
paper identifies a number of the most important challenges to trust in eCommerce as well as trust-related aspects of key enablers
of eCommerce. From this perspective, the paper studies an impact of convergence on trust within eCommerce to identify several
positive relationships. 相似文献
34.
35.
Stormwater quality simulation models are useful tools for the design and management of sewer systems. Modelling results are highly sensitive to experimental data used for calibration. This sensitivity is examined for three modelling approaches of various complexities (site mean concentration approach, event mean concentration approach and build-up, washoff and transport modelling approach) applied to a typical case study (design of a dry detention tank), accounting for the variability of calibration data and their effect on simulation results. Calibrated models with different calibration data sets were used to simulate 3 years of rainfall with different retention tank specific volumes. Annual pollutant load interception efficiencies were determined. Simulations results revealed (i) that there is no advantage in using the EMC model compared to the SMC model and (ii) that the BWT model resulted in higher design ratios than those given by the SMC/hydraulic approach. For both EMC and BWT models, using an increasing number n of events for calibration leads to narrower confidence intervals for the design ratios. It is crucial for design ratios to account for successive storm events in chronological order and to account for the maximum allowable flow to be transferred to the downstream WWTP. 相似文献
36.
It was found that vanadyl porphyrin complexes synthesized from petroleum metal porphyrin concentrates stimulated epoxidation during the olefin oxygenation process. The yields of obtained oxiranes turned out to be 38–75%, depending on the olefin structure. An epoxidation mechanism that suggests the formation of a protonated dioxygen adduct as an intermediate during oxygenation of olefins in the presence of vanadyl porphyrin complexes was proposed. An analogy is drawn between the epoxide formation reaction upon the catalytic oxygenation of olefins and the Prilezhaev reaction. 相似文献
37.
Presented here are details of the development of a novel membrane integrated circuit (IC) probe card structure based on microsystems technology. The device design allows probing of both solder bumps and pads. A self-limiting sensor was integrated to prolong device lifetime. Comparison with and discussion of the use of modelling is made. Possible enhancements to the probing structure are discussed to improve alignment and measurements. Also shown is data using our microsystems probe card to access a simple IC device. Our device has a contact resistance of less than 0.5 Ω for a force of 0.004 N. A method to implement our probing structure for commercial application and the potential developments which can be made to improve its ease of use are then discussed. 相似文献
38.
The Magnitogorsk Metallurgical Combine has conducted a study of the effect of technological factors on the hydrogen content
of chromium-nickel-molybdenum steel after vacuum degassing. It was established that the most important factor is the hydrogen
content of the steel before the degassing operation. The study also determined the effects of the circulation coefficient,
the duration of the degassing operation, and the vacuum used in the treatment.
__________
Translated from Metallurg, No. 7, pp. 68–69, July, 2006. 相似文献
39.
Good requirements practices are neither necessary nor sufficient 总被引:2,自引:2,他引:0
40.
Isolating applied mathematics from computer science harms the profession and those who depend on it. 相似文献