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Nasro Min-Allah Samee Ullah Khan Nasir Ghani Juan Li Lizhe Wang Pascal Bouvry 《The Journal of supercomputing》2012,59(3):1419-1430
With the increased penetration of real-time systems into our surroundings, the selection of an efficient schedulability test
under fixed priority system from a plethora of existing results, has become a matter of primary interest to real-time system
designers. The need for a faster schedulability tests becomes more prominent when it applies to online systems, where processor
time is a sacred resource and it is of central importance to assign processor to execute tasks instead of determining system
schedulability. Under fixed priority nonpreemptive real-time systems, current schedulability tests (in exact form) can be
divided into: response time based tests, and scheduling points tests. To the best of our knowledge, no comparative study of
these test to date has ever been presented. The aim of this work is to assist the system designers in the process of selecting
a suitable technique from the existing literature after knowing the pros and cons associated with these tests. We highlight
the mechanism behind the feasibility tests, theoretically and experimentally. Our experimental results show that response
time based tests are faster than scheduling points tests, which make the response time based tests an excellent choice for
online systems. 相似文献
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Shakir Ullah A. Qayyum 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2009,267(18):3059-3062
Here we describe a recently developed direct Monte Carlo program to study kinetic electron emission from SiO2 target. The program includes excitation of the target electrons (by projectile ions, recoiling target atoms and fast primary electrons), subsequent transport and escape of these electrons from the target surface. The program can be used to calculate the electron yields, distribution of electron excitation points in the target and other physical parameters of the emitted electrons. In order to demonstrate the capabilities of this program, we report a study on the kinetic electron emission from SiO2 induced by fast (1-10 keV) rare gas ions. The calculated kinetic electron yield for various ion energies and masses is in good agreement with the predictions of most frequently applied theoretical model. In addition, the effects of projectile energy, mass and impact angle on the depth distribution of electron excitation points and average escape depth of the outgoing electrons were investigated. It is important to mention that the existing experimental techniques are not capable to measure these parameters. 相似文献
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New magnesium nanocomposites reinforced with copper–graphene nanoplatelet hybrid particles have been prepared through the semipowder metallurgy method. Compared with the monolithic Mg, the Mg–1Cu–xGNPs nanocomposites exhibited higher tensile and compressive strength. In tension, nanocomposites revealed substantial enhancement in elastic modulus, 0.2% yield strength, ultimate tensile strength and failure strain (up to +89, +117, +58 and +96% respectively) compared to monolithic Mg. In compression, the nanocomposites showed the greatest improvement in 0.2% yield strength, and the ultimate compressive strength and failure strain (%) (up to +34, +59 and +61% respectively), whilst the compressive elastic modulus first increases and then decreases with an increase in the graphene nanoplatelets (GNPs) contents. The enhanced strength of the composites is likely to result from strengthening mechanisms invoked by the addition of Cu–GNPs hybrids. 相似文献
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Muhammad Idrees Saima Batool Qaiser Hussain Hidayat Ullah Mohammad Ibrahim Al-Wabel Mahtab Ahmad 《分离科学与技术》2016,51(14):2307-2317
Farmyard manure (FYM-BC) and poultry manure (PM-BC) derived biochars were applied as adsorbents to remove Cd2+ from water. Results indicated that PM-BC was a more efficient adsorbent than FYM-BC at all experimental conditions. Maximum Cd2+ adsorption was observed at pH 4, temperature 318 K and contact time 1 h, regardless of biochar type. The Langmuir model predicted maximum adsorption capacity of 90.09 mg g?1 for PM-BC. The data fitting to pseudo-second-order model proposed chemisorption of Cd2+ onto biochars. Thermodynamics indicated that adsorption was spontaneous and endothermic. Post-adsorption analysis provided evidences of strong chemical interactions between biochars’ functional groups and Cd2+ ions. 相似文献
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