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排序方式: 共有991条查询结果,搜索用时 15 毫秒
981.
O. P. Modi R. P. Yadav D. P. Mondal R. Dasgupta S. Das A. H. Yegneswaran 《Journal of Materials Science》2001,36(7):1601-1607
Two body abrasive wear behaviour of a zinc-aluminium alloy - 10% Al2O3 composite was studied at different loads (1–7 N) and abrasive sizes (20–275 m) as a function of sliding distance and compared with the matrix alloy. The wear rate of the composite and the matrix alloy has been expressed in terms of the applied load, abrasive size and sliding distance using linear factorial design approach. The study suggests that the wear rate of the alloy and composite follow the following relations:
where, x
1, x
2 and x
3 are the coded values of sliding distance, applied load and abrasive size respectively. It has been demonstrated through the above equations that the wear rate increases with applied load and abrasive size but decreases with sliding distance. The interaction effect of the variables exhibited a mixed behaviour towards the wear of the material. It was also noted that the effect of load is less prominent for the composite than the matrix alloy while the trend reversed as far as the influence of the abrasive size is concerned. 相似文献
982.
Bikash Das Subrata Ghosh Shamashis Sengupta Pascale Auban-Senzier Miguel Monteverde Tamal Kumar Dalui Tanima Kundu Rafikul Ali Saha Sujan Maity Rahul Paramanik Anudeepa Ghosh Mainak Palit Jayanta K. Bhattacharjee Rajib Mondal Subhadeep Datta 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(39):2302240
Manipulation of long-range order in 2D van der Waals (vdW) magnetic materials (e.g., CrI3, CrSiTe3 ,etc.), exfoliated in few-atomic layer, can be achieved via application of electric field, mechanical-constraint, interface engineering, or even by chemical substitution/doping. Usually, active surface oxidation due to the exposure in the ambient condition and hydrolysis in the presence of water/moisture causes degradation in magnetic nanosheets that, in turn, affects the nanoelectronic /spintronic device performance. Counterintuitively, the current study reveals that exposure to the air at ambient atmosphere results in advent of a stable nonlayered secondary ferromagnetic phase in the form of Cr2Te3 (TC2 ≈160 K) in the parent vdW magnetic semiconductor Cr2Ge2Te6 (TC1 ≈69 K). The coexistence of the two ferromagnetic phases in the time elapsed bulk crystal is confirmed through systematic investigation of crystal structure along with detailed dc/ac magnetic susceptibility, specific heat, and magneto-transport measurement. To capture the concurrence of the two ferromagnetic phases in a single material, Ginzburg-Landau theory with two independent order parameters (as magnetization) with a coupling term can be introduced. In contrast to the rather common poor environmental stability of the vdW magnets, the results open possibilities of finding air-stable novel materials having multiple magnetic phases. 相似文献
983.
In determination of optimum Type-II progressive censoring scheme, the experimenter needs to carry out an exhaustive search within the set of all admissible censoring schemes. The existing recommendations are only applicable for small sample sizes. The implementation of exhaustive search techniques for large sample sizes is not feasible in practice. In this article, a meta-heuristic algorithm based on variable neighborhood search approach is proposed for large sample sizes. It is found that the algorithm gives exactly the same solution for small sample sizes as the solution obtained in an exhaustive search; however, for large sample sizes, it gives near-optimum solution. We have proposed a cost function-based optimum criterion, which is scale invariant for location-scale and log-location-scale families of distribution. A sensitivity analysis is also considered to study the effect of misspecification of parameter values or cost coefficients on the optimum solution. 相似文献
984.
Ultrathin films of nanocrystalline α-Fe2O3 have been deposited on glass substrates from an inorganic precursor, iron nitropruside. This is a novel route of synthesis for iron oxide thin films on glass substrates, by annealing the precursor thin film in air at 650 °C for 15 min. The films were characterized using TG-DTA analysis, X-ray diffraction, UV-visible, FESEM, AFM and Raman measurements. X-ray diffraction and Raman analyses revealed that the deposited films contain α-phase of Fe2O3 (hematite). The synthetic route described here provides a very simple and cost-effective method to deposit α-Fe2O3 thin films on glass substrates with band gap energy of about 2.75 eV. The deposited films were found to show catalytic effect for the photo-degradation of phenol. 相似文献
985.
Microporous Hydroxyapatite Ceramic Composites as Tissue Engineering Scaffolds: An Experimental and Computational Study 下载免费PDF全文
Satish Kanhed Shikha Awasthi Swati Midha Jitin Nair Ambreen Nisar Anup Kumar Patel Aditi Pandey Rajeev Sharma Sneha Goel Anish Upadhyaya Sourabh Ghosh Kantesh Balani 《Advanced Engineering Materials》2018,20(7)
986.
Sungjune Park Umaash Nallainathan Kunal Mondal Pratik Sen Michael D. Dickey 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(20)
Buckling instabilities generate microscale features in thin films in a facile manner. Buckles can form, for example, by heating a metal/polymer film stack on a rigid substrate. Thermal expansion differences of the individual layers generate compressive stress that causes the metal to buckle over the entire surface. The ability to dictate and confine the location of buckle formation can enable patterns with more than one length scale, including hierarchical patterns. Here, sacrificial “ink” patterned on top of the film stack localizes the buckles via two mechanisms. First, stiff inks suppress buckles such that only the non‐inked regions buckle in response to infrared light. The metal in the non‐inked regions absorbs the infrared light and thus gets sufficiently hot to induce buckles. Second, soft inks that absorb light get hot faster than the non‐inked regions and promote buckling when exposed to visible light. The exposed metal in the non‐inked regions reflects the light and thus never get sufficiently hot to induce buckles. This second method works on glass substrates, but not silicon substrates, due to the superior thermal insulation of glass. The patterned ink can be removed, leaving behind hierarchical patterns consisting of regions of buckles among non‐buckled regions. 相似文献
987.
Corrosion behaviour of two newly developed axle steels (MS3 and MS6) is critically analysed and compared with that of the conventional railway axle steel with respect to the rust formed on the surface and microstructure of the steels. The microstructure of all three steels is ferrite–pearlite. Immersion, salt-fog exposure and dynamic polarisation tests in 3.5 wt% NaCl solution are carried out. New steels have much better mechanical properties and comparable corrosion resistance in immersion and dynamic polarisation test and much better corrosion resistance in salt-fog exposure test than that of the conventional axle steel. 相似文献
988.
Kale A Kale S Yadav P Gholap H Pasricha R Jog JP Lefez B Hannoyer B Shastry P Ogale S 《Nanotechnology》2011,22(22):225101
A new synthesis protocol is described to obtain a CdTe decorated magnetite bifunctional nanosystem via dodecylamine (DDA) as cross linker. High resolution transmission electron microscopy (HRTEM), energy-dispersive x-ray spectroscopy (EDAX), vibrating sample magnetometry (VSM), Fourier transform infrared spectroscopy (FTIR), diffuse reflectance spectroscopy (DRS) and fluorescence microscopy are used to characterize the constitution, size, composition and physical properties of these superparamagnetic-fluorescent nanoparticles. These CdTe decorated magnetite nanoparticles were then functionalized with anti-epidermal growth factor receptor (EGFR) antibody to specifically target cells expressing this receptor. The EGFR is a transmembrane glycoprotein and is expressed on tumor cells from different tissue origins including human leukemic cell line Molt-4 cells. The magnetite-CdTe composite nanosystem is shown to perform excellently for specific selection, magnetic separation and fluorescent detection of EGFR positive Molt-4 cells from a mixed population. Flow cytometry and confocal laser scanning microscopy results show that this composite nanosystem has great potential in antibody functionalized magnetic separation and imaging of cells using cell surface receptor antibody. 相似文献
989.
Copper has been investigated as a potential alloying element in the molten Zn bath and was found to have significant effects in phase formation kinetics as well as corrosion performance. In the present work, the effect of a prior-Cu coating process on hot-dip Zn coating morphology and thickness has been investigated. A thin layer of Cu was coated on steel by a displacement reaction having a thickness of 70–90?nm. The Cu and Zn coatings were characterised using glow discharge optical emission spectroscope, scanning electron microscope and confocal laser scanning microscope. The prior-Cu coating acted as a barrier to Fe dissolution and altered the substrate surface roughness as well as the interfacial energies resulting in modification of nucleation and growth of Fe–Zn intermetallic phases. 相似文献
990.
The deformation behavior of several single-and two-phase coarse microstructures has been examined using microhardness measurements.
It has been found that the strength response of a coarse phase in isolation is distinctly different from its response when
it exists in a two-phase system. The second phase alters the mechanical state of the first one andvice versa even in the plastically undeformed condition. This phenomenon is explained in terms of the existence of an appreciable amount
of residual stresses in two-phase coarse microstructures. These stresses primarily arise due to the difference in thermal
expansion coefficients of the phases. The influence of elastic stress field on microhardness response is shown with a new
type of experiment to support the proposed explanation. The present results question the existing expressions for deformation
modeling of multiphase materials because of the uncertainties in the estimation of the average strength of the phases in a
two-phase system. 相似文献