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排序方式: 共有455条查询结果,搜索用时 15 毫秒
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Bayraktar Murat Pamik Murat Sokukcu Mustafa Yuksel Onur 《Clean Technologies and Environmental Policy》2023,25(7):2233-2248
Clean Technologies and Environmental Policy - Alternative fuels especially those produced in a green way are essential for meeting supplying the world's growing energy needs. Biodiesel is... 相似文献
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The synthesis and characterization of the resin Amberlite XAD-4 functionalized with 2,6-pyridinedicarboxaldehyde and its application in an on-line system for the preconcentration of cadmium, cobalt, copper, lead and manganese prior to determination using flame atomic absorption spectrometry (FAAS) is proposed. Metal ions retained on the modified resin were eluted using 1.0 mol L−1 HNO3 solution and aspirated directly to the nebulizer–burner system of a FAAS instrument using a flow injection system. Detection limits (3σ) were determined to be 0.13 μg L−1 for Cd, 0.29 μg L−1 for Cu, 0.23 μg L−1 for Mn, 0.58 μg L−1 for Co and 2.19 μg L−1 for Pb using a 10 mL of water sample loading volume. The limits of detection would be 100 times higher with units of μg kg−1 for the solid samples in which their dilution ratios as (volume/weight) were 100. Enrichment factors ranged from 23.6 to 28.9 (for Co and Mn, respectively). The proposed method was successfully applied to determination of the analytes in natural water samples and certified reference materials. 相似文献
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Tamer Sınmazçelik Onur Çoban Mustafa Özgür Bora Volkan Günay İsmail Cürgül 《Applied Composite Materials》2008,15(2):99-113
The effects of thermal cycles on the impact fatigue properties of unidirectional carbon fibre reinforced polyetherimide (PEI)
matrix composites were investigated. During the thermal cycles, samples were immersed into boiling water (100 °C) and subsequently
to ice water (0 °C), 50, 200 and 500 times. The changes in viscoelastic properties of the composites were investigated by
means of dynamic mechanical thermal analyzer (DMTA). At the second step, thermal cycled composites were subjected to repeated
impact loadings, with different impact energies. Instrumented impact test results were presented as a function of force, energy,
deformation during the experiments. The scanning electron microscope (SEM) studies were done in order to understand the morphology
of fractured samples after impact fatigue loading. The number of thermal cycles and applied impact energy of the hammer are
found to have a great importance on the fracture morphology of repeatedly impacted material, as expected. 相似文献
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Soner Sismanoglu Aliye Tugce Gurcan Zuhal Yildirim-Bilmez Burak Gumustas 《International Journal of Applied Ceramic Technology》2021,18(2):312-318
Information on the mechanical properties and repairability of computer-aided design/computer-aided manufacturing (CAD/CAM) blocks is scarce. Five CAD/CAM blocks with similar indications were evaluated, including four resin nanoceramics, one polymer-infiltrated ceramic network (PICN), and one feldspathic ceramic. CAD/CAM blocks were sectioned into 4 mm × 1.2 mm × 13 mm bars for flexural strength (FS), and 4 mm thick blocks were prepared for elastic modulus (EM), nanohardness (NH), and microshear bond strength (µSBS) testing. FS of the CAD/CAM blocks was determined using a three-point bending test, whereas EM and NH values were measured using a nanoindenter. The reparability of the tested block materials was determined by the µSBS test. One-way ANOVA was conducted for FS, EM, NH, and µSBS followed by Tukey's pairwise comparison (α < 0.05). FS ranged from 115 to 207 MPa, EM from 8.21 to 44 GPa, NH from 0.76 to 7.24, and µSBS from 24.9 to 30.6 MPa. The findings of the present study revealed that resin nanoceramic blocks exhibited higher FS values than PICN and feldspathic ceramic, and they have acceptable mechanical properties for the fabrication of single-unit restorations according to the ISO 6872:2008. Furthermore, all CAD/CAM blocks tested can be successfully repaired regarding their recommended repair protocol. 相似文献
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Huseyin Avci Esra Akkulak Hazal Gergeroglu Hamed Ghorbanpoor Onur Uysal Ayla Eker Sariboyaci Bahar Demir Merve Nur Soykan Suat Pat Reza Mohammadigharehbagh Ceren Özel Ahmet Cabuk Fatma Doğan Güzel 《应用聚合物科学杂志》2020,137(26):49184
Among the thermoplastic elastomers that play important roles in the polymer industry due to their superior properties, styrene-based species and polyurethane block copolymers are of great interest. Poly(styrene-ethylene-butadiene-styrene) (SEBS) as a triblock copolymer seems to have the potential to meet many demands in different applications due to various industrial requirements where durability, biocompatibility, breaking elongation, and interfacial adhesion are important. In this study, the SEBS triblock copolymer was functionalized with natural (Satureja hortensis, SH) and synthetic (nanopowder, TiO2) agents to obtain composite nanofibers by electrospinning and electrospraying methods for use in biomedical and water filtration applications. The results were compared with thermoplastic polyurethane (TPU) composite nanofibers, which are commonly used in these fields. Here, functionalized SEBS nanofibers exhibited antibacterial effect while at the same time improving cell viability. In addition, because of successful water filtration by using the SEBS composite nanofibers, the material may have a good potential to be used comparably to TPU for the application. 相似文献
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In this paper, we consider two convex optimisation problems in order to maximise the mixing rate of a Markov chain on an undirected path. In the first formulation, the holding probabilities of vertices are identical and the transition probabilities from a vertex to its neighbours are equal, whereas the second formulation is the more general reversible Markov chain with the same degree proportional stationary distribution. We derive analytical results on the solutions of the optimisation problems and compare the spectra of the associated transition probability matrices. 相似文献