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排序方式: 共有211条查询结果,搜索用时 31 毫秒
1.
THERMAL SPRAYING provides a large range ofcoatings,which increase the wear resistance ofsubstrates[1].One of the major coating families is thecermet,composed of hard ceramic particles with ametallic binder.The most commonly used cermetcoatings in industrial applications are based on eitherthe WC-Co or the Cr3C2-Ni(Cr)systems with WC-17wt%Co and Cr3C2-25wt%Ni(Cr)being typicalcompositions[2,3].Although WC-Co deposits are hardand wear resistant at ambient temperatures their rangeof ap… 相似文献
2.
A. J. Horlock Z. Sadeghian D. G. McCartney P. H. Shipway 《Journal of Thermal Spray Technology》2005,14(1):77-84
Recently, there has been considerable interest in producing cermet coatings with nanoscale carbide grains in the size range
50 to 500 nm. In this article, the production of nanoscale TiC grains in a Ni-based alloy matrix by reactive high-velocity
oxyfuel (HVOF) spraying of metastable Ni-Ti-C powder is reported. Mechanical alloying of a Ni(Cr) prealloyed powder and Ti
and C elemental powders was performed in a planar-type ball mill, and materials were characterized in detail using x-ray diffraction
(XRD) and scanning electron micros-copy (SEM). Phase changes were correlated with milling time and other processing conditions.
Results show that, by the selection of appropriate conditions, a metastable Ni-Ti-C powder could be obtained with the nominal
composition 50wt.%Ni-40wt.%Ti-10wt.%C. Following sieving and classification, powder was produced with a particle size range
of −38 to 8 μm, which is suitable for HVOF spraying. Coatings, approximately 250 μm thick, were deposited by HVOF spraying
onto mild steel substrates, and the microstructures formed were investigated. XRD showed that a self-propagating high-temperature
synthesis (SHS) reaction had occurred in the powder particles during spraying and that the principal phases present in the
coating were TiC and a Ni-rich solid solution; small quantities of NiTi, TiO2, and NiTiO3 were also present. SEM revealed that the coatings had a characteristic, splatlike morphology and that TiC formed as a nanoscale
dispersion, with a size range of ∼50 to 200 nm, within solidified splats. The microstructures of these reactively sprayed
Ni-TiC coatings are briefly compared with those observed in HVOF-sprayed coatings deposited using prereacted SHS powder.
The original version of this paper was published as part of the ASM Proceedings, Thermal Spray 2003: Advancing the Science and Applying the Technology, International Thermal Spray Conference (Orlando, FL), May 5–8, 2003, Basil R. Marple and Christian Moreau, Ed., ASM International,
2003. 相似文献
3.
Zohreh Malek-Hosseini 《先进材料力学与结构力学》2017,24(10):875-884
In this article, the dynamic response of a viscoelastic beam with moderately large deflection subjected to transverse and axial loads is studied using the first-order shear deformation theory. The von-Karman strain displacement relations and Hooke's law are used for formulation. The solution of the equations, which are a system of nonlinear partial differential equations, are obtained analytically using the perturbation technique in conjunction with the eigenfunction expansion method. The results are compared with the finite elements method. Also, a sensitivity analysis is performed, and the effects of geometrical and material properties are investigated on the response. 相似文献
4.
Alireza Azizi Elahe Ahmadi Feijani Zohreh Ghorbani Ahmad Tavasoli 《International Journal of Hydrogen Energy》2021,46(2):2244-2254
Metal organic frameworks (MOFs) with marvelous properties have aroused enormous attention for different application especially gas adsorption and separation. In this regard, fabrication of MOF hybrids with carbon based materials is new strategy to upgrade MOF performance. In this study CuBTC (Copper benzene-1,3,5-tricarboxylic acid)/graphene oxide (GO) composite was synthesized and characterized by BET, SEM, TGA, XRD and FT-IR techniques. Then CuBTC and CuBTC/GO composite were incorporated into polysulfone (PSF) polymer to construct mixed matrix membranes (MMMs). The obtained membranes were characterized by SEM, TGA, XRD and tensile tests and their gas permeability was measured. The results were compared to those of CuBTC/PSF MMMs. It was revealed that CuBTC/GO composite as filler showed superior performance relative to CuBTC. For instance, 15 wt% loading of CuBTC/GO in PSF represented outstanding gas separation behavior while the same loading of CuBTC in PSF deteriorated performance of MMM. Well particle dispersion and favorable polymer-filler interaction were responsible for such observed difference. A high H2/CH4 and H2/N2 selectivity of 80.03 and 70.46 were recorded for CuBTC/GO in PSF (15 wt%) compared to 44.56 and 40.92 for CuBTC in PSF (15 wt%). 相似文献
5.
6.
Koosha Fereshteh Farsangi Zohreh Jomeh Samadian Hadi Amini Seyed Mohammad 《Journal of Porous Materials》2021,28(6):1961-1968
Journal of Porous Materials - The development of theranostic nanostructures is one of the most advanced branches of pharmaceutical and medical sciences in the world today. Due to the unique... 相似文献
7.
Ali Akbar Amooey Shahram Ghasemi Seyed Mohammad Mirsoleimani-azizi Zohreh Gholaminezhad Mohammad Javad Chaichi 《Korean Journal of Chemical Engineering》2014,31(6):1016-1020
Electrocoagulation (EC) is an electrochemical method to treat polluted wastewaters and aqueous solutions. In this paper, the removal of Diazinon was studied by EC on aluminum electrode. The effect of several parameters such as initial concentration of Diazinon, current density, solution conductivity, effect of pH, and electrolysis time were investigated on EC performance. The obtained results showed that the removal efficiency of EC depends on the current density, initial concentration of Diazinon and electrolysis time. The optimum pH is 3 and also the solution conductivity has no significant effect on removal efficiency. 相似文献
8.
Today, millions of electrocommunication, electric, medical, and industrial devices use battery. Batteries with long life and high energy density seem to be essential in medical, military, oil and mining, aerospace areas as well as conditions in which access is difficult and in situations where replacement or recharging of battery is costly.In this regard, the use of radiation energy resulting from radioactive materials and its conversion to electric energy can be effective in making batteries. In the present study,various Mo-99 radioisotope values with a half-life of 65.98 h were used as a soluble radioactive source in two materials of water and aqua regia. Then, by comparing the results of the Monte Carlo simulations program MCNPX for these two solutions, it was found that when the water is used instead of aqua regia(for idealization), the values of the superficial current of electrons, the volumetric flux of electrons, and the deposited energy in the volume containing the radioactive solution increased by 10.80, 4.10,and 13.80%, respectively. Also, the short-circuit current and energy conversion efficiency of this battery with a concentration of 0.01 molar, Mo-99 dissolved in the aqua regia are 0.79μA and 16.47%, respectively. 相似文献
9.
A new one-dimensional silver(I) coordination polymer, [Ag(μ-bpfb)(NO3)]n (1); bpfb = N,N′-bis(4-pyridylformamide)-1,4-benzene, has been synthesized and characterized by IR, 1H NMR and 13C NMR spectroscopy. The single crystal X-ray data show that the silver(I) 1D coordination polymer grows into a three-dimensional network by hydrogen bonding and π–π stacking interactions. Compound 1 with nanorod morphology was also prepared by sonochemical method. The cetyltrimethylammonium bromide (CTAB) as a cationic surfactant was used in reverse micelles technique to obtain spongy silver(I) bromide nanoparticles from compound 1. Also, different silver nanoparticles have been prepared via direct calcination at 673 K and thermal decomposition in oleic acid from compound 1. The nanostructures of [Ag(μ-bpfb)(NO3)]n (1), silver and silver(I) bromide were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray (EDAX) analysis. Thermal stability of compound 1 in both bulk and nano-sized form was studied by thermal gravimetric (TG) and differential thermal (DT) analyses. 相似文献
10.
M. Salarian A. Mirzaghorbanali H. Ghasemzadeh S. Sadeghian 《Petroleum Science and Technology》2013,31(19):2066-2075
Abstract Well bore instability problems are difficult without actual geomechanical models. With advanced geomechanical problems such as dynamic well bore instabilities, an otherwise routine well bore instability problem escalates into a disastrous instability. It is common that, in areas where instabilities are infrequent, contractors and operators become complacent with poorly designed system. Consequently, when dynamic well bore instabilities do occur, the designed models are inadequate, mechanical problems compound the situation, and a disaster follows. Until now, not many researchers have taken into account the influences of dynamic instabilities in casing design while several situations reported in which the completed well subjected to failure due to the dynamic displacements. This study is intended to develop a new pragmatic geomechanical model to design casing based on ground motions around the drilled well. This model is applied and verified against field data and numerical model in the South Pars Gas Field (phases 6, 7, and 8 and well number SPDG-8) in Persian Gulf. The results indicate that dynamic displacements must be considered in design whenever the well is drilled in a zone where an earthquake is possible. 相似文献