排序方式: 共有23条查询结果,搜索用时 359 毫秒
1.
2.
3.
Yaser Pourmohammadi Fallah Samer El-Housseini Hussein Alnuweiri 《Wireless Personal Communications》2008,47(2):235-245
The main service differentiation mechanism introduced by the IEEE 802.11e standard is described in terms of prioritized contention
access. Analyzing the performance and service differentiation ability of each of the priority features of the 802.11e standard
is an important task, and considerable research effort has recently been dedicated to this subject. In this article, we present
a generalized and comprehensive analysis of the prioritized access scheme of the 802.11e standard. Our model corrects and
extends the existing models and considers all priority features of the 802.11e Medium Access Control (MAC) protocol. We consider
an arbitrary number of priority levels, and provide a detailed parametric analysis of the MAC behavior for the main priority
parameters of inter frame spacing, contention window size, and transmission opportunity. We validate the accuracy of our analysis
with simulation experiments.
相似文献
Hussein AlnuweiriEmail: |
4.
5.
6.
Mohammad Mehdi Foroughi Shohreh Jahani Zahra Aramesh-Boroujeni Meisam Rostaminasab Dolatabad Kiana Shahbazkhani 《Ceramics International》2021,47(14):19727-19736
In this experiment, an original three-dimensional (3D) cubic of europium (Eu) 3+/cuprous oxide (Cu2O) with clover-like face-centered nanostructures (Eu3+/Cu2O CLFNs) was successfully synthesized to determine nevirapine (C15H14N4O), using electrochemical methods. The surface morphology of the Ns was correspondingly identified through different techniques, including energy dispersive X-ray spectroscopy (EDX), X-ray powder diffraction (XRD), and scanning electron microscopy (SEM). In this sense, the synergistic influence of the Eu3+/Cu2O CLFNs enhanced the electrocatalytic capability of the electrode via a modified glassy carbon (GC) and raised the active site. Employing various approaches, the modified electrode was then analyzed through cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Moreover, kinetic parameters and electrochemical ones were estimated by means of voltammetric methods. For the determination of nevirapine applying the Eu3+/Cu2O CLFNs/GC electrode (GCE), differential pulse voltammetry (DPV) was further utilized. Under optimized conditions, the range of linear responses was between 0.01 and 750.0 μM with the limit of detection (LOD) of 3.6 nM, whereas the recommended sensor sensitivity was equal to 0.1244 μA/μM. The response time of approximately 3.5 min and the reproducibility (inter- and intra-electrode reproducibility of 2.26% and 1.51%, respectively) were subsequently achieved. It was concluded that sensors have been thus far exploited to determine nevirapine in real samples with favorable outcomes, indicating that electrocatalysis modifier can be assumed as one of appropriate catalysts. 相似文献
7.
8.
Allison MacDonald Babak Karamy Kiana Setoodehnia Balraj Singh 《Nuclear Data Sheets》2013,114(2-3):397-433
A compilation of the nuclear spins of ground and isomeric states measured by direct methods is presented. The first compilation of direct measurements of nuclear spins and moments was published in 1976 (G. H. Fuller, J. Phys. Chem. Ref. Data 5, 835, (1976)) with literature covered up to 1974. To our knowledge, the present work is the first such compilation since then. It is anticipated that the area of direct spin measurement will continue to expand using the state-of-the-art radioactive ion-beam and laser techniques. Literature cutoff date for the present compilation is February 2013. It is intended that the present compilation will be kept updated in a timely manner. 相似文献
9.
10.
Polymeric nanofibers as one of the most known nanotechnology products have huge potential applications in many fields due to their high aspect ratio and porosity, being capable of formation of three-dimensional structures and having great mechanical and biological properties. Chitosan is a natural abundant polymer which has attracted huge interests in biomedical and biological industries due to its biocompatible, biodegradable, and non-toxicity properties. However, electrospinning of chitosan is found to be a great challenge, blending it with other polymers such as gelatin was explored as means to improve the morphological deficiencies of chitosan nanofibers and facilitate its electrospinnability. On the other hand, montmorillonite (MMT) has been attracted great attention due to its remarkable improvement in properties of polymeric composites nanofibers. The main objective of this work was on effect of concretion of gelatin–chitosan blends and MMT on morphology of resulted nanocomposite nanofibers. The x-ray diffraction data demonstrated the exfoliation of MMT layers. The morphology of electrospun chiosan–gelatin–MMT composite nanofibers was characterized using scanning electron microscope (SEM). The miscibility of blend was determined using SEM and Fourier transform infrared spectrometer/attenuated total reflectance. 相似文献