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排序方式: 共有147条查询结果,搜索用时 93 毫秒
81.
82.
Safak Dogan Nihan Akin Ceren Baskose Tarik Asar Tofig Memmedli Suleyman Ozcelik 《材料科学与工程:中英文B版...》2013,(8):518-523
Porous silicon layers manufactured by using (100), 1-5 ohm-cm p-type (boron doped) wafer by electrochemical etching in HF etanol solution. Photoluminescence (PL) spectra of anodically etched silicon obtained for different conditions studied and surface characteristics are investigated by AFM. This study gives a simple way to determine specific surface are of porous silicon which plays a major role with porosity for explaining the blue shift in photoluminescence peak. Properties such as specific surface area, pore size, and pore size distribution, the main surface properties of layer are investigated from AFM data which are important material characteristics in many processing applications. The "specific surface area" (Sspecific) generally defined as the area of solid surface per unit mass of material, solid volume or cross section area. From 3-D reconstructions of AFM data, the surface area and the volume of the porous layer can be estimated directly and volume-surface specific area is calculated. For porous silicon this feature can be defined as the total surface area per volume and given by the unit m2/cm3. The method is simple not need to construct a special set up for measurement and non destructive. 相似文献
83.
Tarik Aydoğmuş Elif Tarhan Bor Şakir Bor 《Metallurgical and Materials Transactions A》2011,42(9):2547-2555
Porous TiNi alloys with porosities in the range of 51 to 73 pct were prepared successfully applying a new powder metallurgy
fabrication route in which magnesium was used as a space holder, resulting in either single austenite phase or a mixture of
austenite and martensite phases dictated by the composition of the starting powders, but entirely free from secondary brittle
intermetallics, oxides, nitrides, and carbonitrides. Since transformation temperatures are very sensitive to composition,
deformation, and oxidation, for the first time, transformation temperatures of porous TiNi alloys were investigated using
chemically homogeneous specimens in as-sintered and aged conditions eliminating secondary phase, contamination, and deformation
effects. It was found that the porosity content of the foams has no influence on the phase transformation temperatures both
in as-sintered and aged conditions, while deformation, oxidation, and aging treatment are severely influential. 相似文献
84.
Konstantinos Samdanis Tarik Taleb Dirk Kutscher Marcus Brunner 《Mobile Networks and Applications》2012,17(1):119-131
Energy efficiency is a significant requirement for the design and management of mobile networks and has recently gained substantial
attention from both network operators and the research community. The general concept of energy saving management aims to
match the capacity offered by operators to the actual demand at given times and geographic areas. This paper introduces the
notion of energy partition, an association of powered-on and powered-off BSs to deliver network-level energy saving. It then
elaborates how such concept is applied to perform energy re-configuration to flexibly re-act to load variations encouraging
none or minimal extra energy consumption. A simulation-based study evaluates the performance of the proposed algorithms under
different network topologies and traffic conditions, highlights the benefits and drawbacks, and provides recommendations for
deployment scenarios. 相似文献
85.
Physical Internet (PI) was introduced as a global standardised and interconnected logistics system based on PI-nodes, PI-movers and PI-containers as a mean toward global logistics sustainability. One important issue regarding PI-nodes concerns the planning and scheduling of operations and the management of PI-containers, both in a deterministic and a perturbed environment. This research considers the Road-Rail PI-hub sustainable truck scheduling and PI-containers grouping problem. In our research we consider the weighted sum of the number of used wagons, the internal distance travelled by PI-containers from PI-docks to wagons as well as the trucks’ tardiness, which translate the search for sustainable logistics. In this paper, an effective and reactive multi-agent system based model (MAS) is developed for the resolution of the trucks scheduling and PI-containers grouping. To ensure the efficiency of the MAS and improve the quality of each of its solutions, three concurrent hybrid meta-heuristics are embedded within three parallel scheduling agents. Then, a mixed integer linear programming model (MILP) is proposed to evaluate the performance of the MAS. Finally, the MAS is also evaluated under internal perturbations. The obtained results show the ability of the MAS to provide alternative sustainable solutions by rescheduling trucks in case of disruptions. 相似文献
86.
孔径为0.038μ并且总表面积为540m^2的平板膜生物反应器(MBR)在安卡拉METU大学间歇式运行了一年,用于处理来自宿舍和学院楼的家庭污水。MBR设备的第一阶段连续运行140天,水力保留时间在18-22h。这段时间内,污泥浓度从开始的2.4g/L增加到21g/L。当DO保持超过2.0mg/L时,该设备可以稳定地生产完全硝化的排出水。 相似文献
87.
Mohamed Issam Ziane Zouaoui Bensaad Tarik Ouahrani Boutaleb Labdelli Hamza Ben Nacer Hamza Abid 《Materials Science in Semiconductor Processing》2013,16(4):1138-1147
To investigate the structural and electronic properties of zinc blende GaNxAs1?x alloys, we performed full-potential linearized augmented plane wave (FP-LAPW) calculations based on density functional theory. We assessed GaNxAs1?x alloys for 0≤x≤1 using 16-atom special quasi-random structures. The generalized gradient approximation (GGA) of Wu and Cohen was used as the exchange correlation potential to calculate the structural and electronic properties of GaNxAs1?x. In addition, the alternative GGA proposed by Engel and Vosko and the modified Becke–Johnson potential were used for better reproduction of the band structure and electronic properties. The equilibrium lattice parameters and bulk modulus were calculated and analyzed for binary and ternary alloys. The lattice constants for GaNxAs1?x positively deviate from Vegard's law with an upward bowing parameter of ?0.4708 Å. All our materials are direct-bandgap semiconductors for which the valence band maximum is located at Γv and the conduction band minimum at Γc. We observed that the direct bandgap of GaNxAs1?x increases nonlinearly with x. To shed light on the bandgap trend for increasing nitrogen concentrations in GaNxAs1?x, we used the atoms-in-molecule formalism. Special attention was paid to the increase in charge transfer for the nitrogen atom and to ionicity as a function of increasing x concentration. 相似文献
88.
Gregory J. Gabriel Abhigyan Som Ahmad E. Madkour Tarik Eren Gregory N. Tew 《Materials Science and Engineering: R: Reports》2007,57(1-6):28-64
Infectious disease is a critically important global healthcare issue. In the U.S. alone there are 2 million new cases of hospital-acquired infections annually leading to 90,000 deaths and 5 billion dollars of added healthcare costs. Couple these numbers with the appearance of new antibiotic resistant bacterial strains and the increasing occurrences of community-type outbreaks, and clearly this is an important problem. Our review attempts to bridge the research areas of natural host defense peptides (HDPs), a component of the innate immune system, and biocidal cationic polymers. Recently discovered peptidomimetics and other synthetic mimics of HDPs, that can be short oligomers as well as polymeric macromolecules, provide a unique link between these two areas. An emerging class of these mimics are the facially amphiphilic polymers that aim to emulate the physicochemical properties of HDPs but take advantage of the synthetic ease of polymers. These mimics have been designed with antimicrobial activity and, importantly, selectivity that rivals natural HDPs. In addition to providing some perspective on HDPs, selective mimics, and biocidal polymers, focus is given to the arsenal of biophysical techniques available to study their mode of action and interactions with phospholipid membranes. The issue of lipid type is highlighted and the important role of negative curvature lipids is illustrated. Finally, materials applications (for instance, in the development of permanently antibacterial surfaces) are discussed as this is an important part of controlling the spread of infectious disease. 相似文献
89.
90.
Physicochemical characterization and adsorptive properties of some Moroccan clay minerals extruded as lab-scale monoliths 总被引:1,自引:0,他引:1
Sanae Harti Gustavo Cifredo Jos Manuel Gatica Hilario Vidal Tarik Chafik 《Applied Clay Science》2007,36(4):287-296
Textural, structural and adsorptive properties of some Moroccan clays were investigated. The minerals were used as raw material for extrusion of honeycomb monoliths. Adsorption and desorption tests were performed with selected model pollutants such as volatile organic compounds (VOCs). The clays have been chosen, apart from their abundance and price, on the basis of successful extrusion as integral lab-scale honeycomb monoliths. The obtained monoliths have been subjected to measurements of the mechanical strength. 相似文献