SwePub - search: L773:0167 577X

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1.	Fu, Q. X., et al. (author) Doped ceria-chloride composite electrolyte for intermediate temperature ceramic membrane fuel cells 2002 In: Materials letters (General ed.). - 0167-577X .- 1873-4979. ; 53:3, s. 186-192 Journal article (peer-reviewed)abstract A kind of oxide-salt composite electrolyte, gadolinium-doped ceria (GDC)-LiCl-SrCl2, prepared with hot-press technique, shows superior ionic conductivity, which is 2-10 times higher than that of GDC itself at the temperature range of 400-600 degreesC. More interestingly, not like the GDC electrolyte, which has some extent of electronic conduction under reducing atmosphere, the composite electrolyte is almost a pure ionic conductor, evidenced by the fuel cell's (FC) open circuit voltage (OCV) close to the theoretical one. The fuel cells based on this composite electrolyte show excellent power density output even at temperature as low as 500 degreesC (240 mW cm(-2)) in spite of the relatively thick electrolyte (0.4 mm). Such high performance, in combination with its low cost in both raw materials and fabrication process, make this kind of composite electrolyte a good candidate electrolyte material for future ultra-low-cost intermediate temperature ceramic membrane fuel cells (IT-CMFCs).
2.	Krakhmalev, Pavel, 1973- (author) Isothermal grain growth in mechanically alloyed nanostructured Fe80Ti8B12 alloy 2003 In: Materials Letters. - : Elsevier. - 0167-577X. ; 57:22/23, s. 3671-3675 Journal article (peer-reviewed)abstract Isothermalgraingrowth in a mechanicallyalloyednanostructured Fe80Ti8B12alloy was investigated at 915–985 K by TEM and XRD methods. Crystallization of the amorphous phase and grain coarsening stages were observed, and each stage was analyzed using models of a graingrowth with dragging of grain boundaries and of normal graingrowth, respectively. Activation energies were calculated to be 300±10 and 280±10 kJ/mol using the models.
3.	Krakhmalev, Pavel, 1973-, et al. (author) Microstructure, hardness and indentation toughness of high-temperature C40 Mo(Si,Al)2/SiC composites prepared by SPS of MA powders 2003 In: Materials letters (General ed.). - : Elsevier. - 0167-577X .- 1873-4979. ; 57:22-23, s. 3387-3391 Journal article (peer-reviewed)
4.	Mathew, Aji P., et al. (author) Izod impact behavior of natural rubber/polystyrene interpenetrating polymer networks 2001 In: Materials letters (General ed.). - 0167-577X .- 1873-4979. ; 50:2-3, s. 154-163 Journal article (peer-reviewed)abstract The impact behavior of semi and full interpenetrating polymer networks based on natural rubber (NR) and polystyrene (PS) has been studied with special reference to blend ratio and cross-linking level of PS phase. As the PS cross-linker level increases up to 4% an increase in impact strength values was observed. This behavior was explained based on blend morphology and the fractography. It was also found that in moderately cross-linked IPNs, the blend composition with 70% PS showed maximum impact strength values. At higher cross-linking levels, samples with 60% PS showed maximum impact strength values. The fracture surface morphology satisfactorily explained the nature of failure and impact performance in all cases. Addition of NR to PS has changed the failure mechanism from crazing to shear yielding
5.	Strömme, Maria, et al. (author) What do we do with all these algae? 2002 In: Materials letters (General ed.). - 0167-577X .- 1873-4979. ; 57:3, s. 569-572 Journal article (peer-reviewed)abstract The severe eutrophication of coastal areas is considered to be one of the most serious environmental threats of our time S. Nixon, Ambio 19 (1990) 101. Even if the nutrient outlet is curtailed, carpets of green algae filaments will remain for a long time as the algae life cycle feeds itself S. Naeem, D.R. Hahn, G. Schuurman, Nature 403 (2002) 762. One way to master this ecological problem is to remove algae from the cycle O. Jousson, J. Pawlowski, L. Zaninetti, F.W. Zechman, F. Dini, G. Di Guiseppe, R. Woodfield, A. Millar, A. Meinensz, Nature 408 (2000) 157. Hence, the necessity of finding some relevant use for green algae is obvious. It has been shown that cellulose powder from green algae sources has a higher level of crystallinity and a relatively larger surface area than higher plant cellulose R. Ek, C. Gustafsson, A. Nutt, T. Iversen, C, Nyström, J. Mol. Recognit. 11 (1998) 263. Could these properties possibly be advantageous in pharmaceutical tablet manufacturing? Here, we show that green algae filaments provide an alternative raw material source for the production of microcrystalline cellulose with a hitherto unobserved combination of properties desirable for a tableting excipient.
6.	Toprak, Muhammet S., et al. (author) Chemical alloying and characterization of nanocrystalline bismuth telluride 2003 In: Materials letters (General ed.). - : Elsevier BV. - 0167-577X .- 1873-4979. ; 57:24-25, s. 3976-3982 Journal article (peer-reviewed)abstract A novel chemical alloying method has been developed for the fabrication of nanocrystalline thermoelectric alloy Bismuth telluride, Bi2Te3. The method consists of a combination of solution chemical method and thermal processing under controlled heating conditions. The components have been coprecipitated from a solution and the precursor consists of a solid solution of the different intermediate compounds and exhibits high reactivity. Calcination and hydrogen reduction of the precursor at moderate temperature, 350 degreesC, for 2 h resulted in the alloying of these elements to obtain the pure phase of the thermoelectric material in fine powder. The method is simpler than conventional melt processing and produced a 95-98% yield in laboratory scale. High concentration of grain boundaries provided by nanostructuring is expected to lower the thermal conductivity of thermoelectric material and further increase the performance.
7.	Korsunsky, Alexander M., et al. (author) Quantifying eigenstrain distributions induced by focused ion beam damage in silicon 2016 In: Materials letters (General ed.). - : Elsevier. - 0167-577X .- 1873-4979. ; 185, s. 47-49 Journal article (peer-reviewed)abstract Eigenstrain offers a versatile generic framework for the description of inelastic deformation that acts as the source of residual stresses. Focused ion beam (FIB) milling used for nanoscale machining is accompanied by target material modification by ion beam damage having residual stress consequences that can be described in terms of eigenstrain. Due to the lack of direct means of experimental determination of residual stress or eigenstrain at the nanoscale we adopt a hybrid approach that consists of eigenstrain abstraction from molecular dynamics simulation, its application within a finite element simulation of a flexible silicon cantilever, and satisfactory comparison of the prediction with experimental observation. Directions for further enquiry are briefly discussed. ", keywords = Focused ion beam milling; Molecular dynamics; Eigenstrain; Residual stress, isbn = 0167-577X, doi=https://doi.org/10.1016/j.matlet.2016.08.111
8.	Abbasi, Mazhar Ali, et al. (author) Fabrication of UV photo-detector based on coral reef like p-NiO/n-ZnO nanocomposite structures 2013 In: Materials letters (General ed.). - : Elsevier. - 0167-577X .- 1873-4979. ; 108, s. 149-152 Journal article (peer-reviewed)abstract In this research work, a UV photo-detector is fabricated on fluorine doped tin oxide (FTO) glass substrate by exploiting the advantageous features of p-n heterojunctions based on p-NiO and n-ZnO composite nanostructures forming a coral-reef like structures. Scanning electron microscopy (SEM) and X-ray diffraction results showed uniform morphology and good crystal quality of the synthesised nanostructures respectively. I-V measurements have shown nonlinear and rectifying response of the p-NiO/n-ZnO heterojunction. The proposed photodiode exhibited excellent UV response with acceptable photocurrent generation of about 3.4 mA and the responsivity of 2.27 A/W at -3 biasing voltage.
9.	Aboulfadl, Hisham, 1986, et al. (author) Atomic-scale characterization of diffusion kinetics in Ru/Al multilayer thin films 2019 In: Materials Letters. - : Elsevier BV. - 1873-4979 .- 0167-577X. ; 254, s. 344-347 Journal article (peer-reviewed)abstract The microstructure properties of reactive multilayers play a key role in their chemical reactions. Ru/Al multilayers are investigated in as-deposited and annealed conditions using atom probe tomography to probe the interdiffusion and early phase formation. Performing atom probe analysis was accompanied with difficulties stemming from weak adhesion of the bi-layers and reconstruction artifacts. Nonetheless, it was possible to obtain valuable qualitative information concerning diffusion kinetics. Asymmetric interdiffusion during deposition is found. Grain boundary diffusion is shown to have a major contribution on enhancing mass-transport across the layers as well as on the nucleation and growth of the RuAl6 intermetallic phase.
10.	Aboulfadl, Hisham, 1986, et al. (author) Interdiffusion in as-deposited Ni/Ti multilayer thin films analyzed by atom probe tomography 2019 In: Materials Letters. - : Elsevier BV. - 1873-4979 .- 0167-577X. ; 236, s. 92-95 Journal article (peer-reviewed)abstract The nanoscale design of metallic multilayer thin films is one crucial factor that greatly influences the kinetics, often inducing unusual phase transformations. Metastable or amorphous phases may directly form in as-deposited films of certain thicknesses, which is common for Ni/Ti multilayers. Atom probe tomography and X-ray diffraction analyses are performed here to study the interdiffusion and structural changes as a function of the bilayer thickness in Ni/Ti multilayers. The films are deposited by DC magnetron sputtering with near 50:50 compositions. Multilayers with 5 nm bilayer thickness are found to be highly intermixed, with compositions up to ∼25 at.% for both diffuser metals, inducing amorphization reactions during deposition.
11.	Afroze, Shammya, 1987, et al. (author) Insight of novel layered perovskite PrSrMn2O5+δ: A neutron powder diffraction study 2020 In: Materials Letters. - : Elsevier BV. - 1873-4979 .- 0167-577X. ; 261 Journal article (peer-reviewed)abstract Neutron diffraction is very important to characterizing complex oxide materials, especially for the light element position and occupancy. In this study, a new layered perovskite oxide material, PrSrMn2O5+δ, was prepared by the solid-state reaction method and characterized by using X-ray and neutron powder diffraction, scanning electron microscopy and thermogravimetric analysis. X-ray diffraction data showed that the material adopted orthorhombic symmetry and Rietveld refinement of the neutron diffraction data gave accurate unit cell parameters (a = 3.8907 (1) Å, b = 3.8227 (1) Å, and c = 7.6846 (2) Å, atomic positions and space group (Pmmm)). Scanning electron microscopy showed a porous and interlinked microstructure. Thermogravimetric analysis exhibited two-stage weight losses up to 1000 °C from room temperature, indicating a good amount of oxygen losses and high material stability.
12.	Akhtar, Farid, et al. (author) Reactive sintering and properties of TiB 2 and TiC porous cermets 2008 In: Materials letters (General ed.). - : Elsevier BV. - 0167-577X .- 1873-4979. ; 62:8-9, s. 1242-1245 Journal article (peer-reviewed)abstract TiB2, TiC reinforced Fe matrix porous cermets were produced through the synthesis reaction of Ti, C and FeB powders with 30% sintered porosity. The X-ray diffraction analysis confirmed the completion of reaction. The TiB2, TiC and Fe were detected by X-ray diffraction analysis. The formation of secondary reaction products was inhibited during the reactive sintering. Porous cermets showed large and small pores in their structure. Maximum bending strength of 163 MPa was obtained with 30% sintered porosity. Furthermore, the fabricated samples were found to possess reasonable electrical conductivities, thus rendering them suitable for use as the basic components of planar solid oxide fuel cells.
13.	Akhtar, Farid, et al. (author) TiB 2 and TiC stainless steel matrix composites 2007 In: Materials letters (General ed.). - : Elsevier BV. - 0167-577X .- 1873-4979. ; 61:1, s. 189-191 Journal article (peer-reviewed)abstract Stainless steel matrix composites reinforced with TiB2 or TiC particulates have been in situ produced through the reactive sintering of Ti, C and FeB. X-ray diffraction analysis confirmed the completion of reaction. The TiB2, TiC and steel were detected by X-ray diffraction analysis. No other reaction product or boride was found, indicating the stability of TiB2 and TiC in steel matrix. The SEM micrographs revealed the morphology and distribution of in situ synthesized TiB2 and TiC reinforcements in steel matrix. During sintering the reinforcements TiB2 and TiC grew in different shapes. TiB2 grew in hexagonal prismatic and rectangular shape and TiC in spherical shape.
14.	Askari, SJ, et al. (author) Synthesis and characterization of nano-crystalline CVD diamond film on pure titanium using Ar/CH 4/H 2 gas mixture 2007 In: Materials letters (General ed.). - : Elsevier BV. - 0167-577X .- 1873-4979. ; 61:11-12, s. 2139-2142 Journal article (peer-reviewed)abstract Titanium and Ti alloys have poor tribological properties and deposition of a well adherent diamond coating is a promising way to solve this problem. But diamond film deposition on pure titanium and Ti alloys is always difficult due to the high diffusion coefficient of carbon in Ti, the large mismatch in their thermal expansion coefficients, the complex nature of the interlayer formed during diamond deposition, and the difficulty of achieving very high nucleation density. A nano-crystalline diamond (NCD) film can resolve Ti and Ti alloys weak tribological performance due to its smooth surface. A well-adhered NCD film was successfully deposited on pure Ti substrate by using a microwave plasma assisted chemical vapor deposition (MWPCVD) system in the environment of Ar, CH4 and H2 gases at a moderate temperature. Detailed experimental results on the preparation, characterization and successful deposition of the NCD film on pure Ti are discussed
15.	Balaji, G., et al. (author) Investigations on Hot-wall deposited Cadmium Sulphide buffer layer for thin film solar cell 2018 In: Materials Letters. - : Elsevier BV. - 1873-4979 .- 0167-577X. ; 222, s. 82-87 Journal article (peer-reviewed)abstract Cadmium Sulphide (CdS) thin films were deposited on to well-cleaned soda lime glass substrates using hot wall deposition technique at room temperature. The structure of CdS thin films was found to be hexagonal with < 0 0 2 > orientation and after annealing the film crystallized to < 0 0 2 >, < 1 0 1 >, < 1 0 2 >, < 1 1 2 > directions. Raman Spectroscopy confirmed the hexagonal structure with a shift at 312 cm(1). SAED pattern from the Transmission electron microscopy also confirmed the formation of hexagonal CdS. X-ray Photoelectron Spectroscopy confirmed the formation of CdS with relevant at% of Cd and S. Field emission scanning electron microscopy images revealed smooth surface of the thin film with distinctive grains. Atomic force microscopy results showed a surface roughness of 4.47 nm. Transmission spectra of the films were studied and the transparency was found to be above 80%. The optical band gap was found to be around 2.4 eV in accordance with the reported values. The results show that device quality buffer layers can be deposited using Hot-wall deposition. (C) 2018 Elsevier B.V. All rights reserved.
16.	Ballem, Mohamed, et al. (author) Synthesis of hollow silica spheres SBA-16 with large-pore diameter 2011 In: Materials letters (General ed.). - : Elsevier Science B.V., Amsterdam.. - 0167-577X .- 1873-4979. ; 65:7, s. 1066-1068 Journal article (peer-reviewed)abstract Hollow silica SBA-16 spheres with cubic ordered mesoporous shells were synthesized by an emulsion-templating method, using Pluronic F127 as a structure-directing agent. tetraethyl orthosilicateas as a silica source and heptane as a cosolvent in the presence of NH4F. The size of these spheres is in the range of 10 to 30 mu m. The shell is about 700 nm thick and consists of large pores, similar to 9 nm in diameter, arranged in a cubic order. After calcination, the spheres maintain their mesoporosity and show a high surface area of 822 m(2)/g. The formation mechanism of the silica hollow spheres is discussed.
17.	Becker, Richard, et al. (author) Synthesis of silver nanowires in aqueous solutions 2010 In: Materials letters (General ed.). - : Elsevier BV. - 0167-577X .- 1873-4979. ; 64:8, s. 956-958 Journal article (peer-reviewed)abstract Silver nanowires with a diameter of 30 nm and typical lengths of 5–10 μm have been synthesized in an aqueous medium. To initiate the reaction, citrate ions were used, and during the reaction the aromatic organicmolecules polymerize forming “straight” chain surfactants which support the formation of nanowires. Characterization by TEM and HRETM revealed the nanowires to be highly crystalline with a growth along the [110] direction.
18.	Beygelzimer, Y., et al. (author) Surface sliding revealed by operando monitoring of high-pressure torsion by acoustic emission 2024 In: Materials Letters. - 0167-577X. ; 363 Journal article (peer-reviewed)abstract High-pressure torsion (HPT) is widely used as a key method for microstructure control through deformation processing across a broad range of materials. However, certain gaps in process control impact its efficacy. In this study, we investigate the acoustic emission (AE) signals generated during HPT by considering commercially pure molybdenum as an example. By employing the adaptive sequential k-means algorithm, we analyse the AE stream to categorise and identify its sources. By comparing the kinetics of AE signal evolution during HPT processing at pressures of 2 GPa and 5 GPa, two distinct signal types are identified: one linked to plastic deformation and the other to workpiece slippage over HPT anvil surfaces. This research demonstrates the potential of AE tools for operando monitoring of HPT stability and detection of workpiece slippage, thereby enhancing the processing efficiency.
19.	Blixt, Kevin Hult, et al. (author) Grain boundary stiffness based on phase field crystal simulations 2022 In: Materials Letters. - : Elsevier BV. - 0167-577X. ; 318 Journal article (peer-reviewed)abstract Phase field crystal modeling with wavelet filtering is shown to be an attractive replacement for molecular dynamics simulations when evaluating grain boundary stiffness by the capillary fluctuation method. Obstacles such as iterative equilibration of grain boundary structures and repeated reconstruction of the grain boundary over extended simulations can be avoided.
20.	Botella, Romain, et al. (author) Polarized ATR-IR spectroscopy for the identification of material structure : The case of graphene oxide 2022 In: Materials letters (General ed.). - : Elsevier. - 0167-577X .- 1873-4979. ; 320 Journal article (peer-reviewed)abstract Graphene oxide (GO) is a layered structure similar to graphite, whose planes of carbon atoms are decorated by oxygen-containing groups. These groups bring hydrophilicity and reactivity to GO, as they are present on its basal plane or at the edges. Thus, their identification is essential to determine the chemical properties of GO. Amongst the possible analytical techniques, infrared spectroscopy is suitable to identify these groups. In this work, an advanced spectroscopic method, polarized attenuated total reflectance infrared spectroscopy, was used to obtain a more in-depth analysis of these reactive groups. This new approach has allowed to refine the description of the functional groups at the surface and could be used to follow the evolution surface processes in material chemistry (e.g. grafting reactions).
21.	Boyd, Robert, et al. (author) Complex 3D nanocoral like structures formed by copper nanoparticle aggregation on nanostructured zinc oxide rods 2016 In: Materials letters (General ed.). - : ELSEVIER SCIENCE BV. - 0167-577X .- 1873-4979. ; 184, s. 127-130 Journal article (peer-reviewed)abstract This paper reports a new strategy for nanoparticle surface assembly so that they form anisotropic fibril like features, consisting of particles directly attached to each other, which can extend 500 nm from the surface. The particles are both formed and deposited in a single step process enabled via the use of a pulsed plasma based technique. Using this approach, we have successfully modified zinc oxide rods, up to several hundred nanometers in diameter, with 25 nm diameter copper nanoparticles for catalytic applications. The resulting structure could be modelled using a diffusion limited aggregation based approach. This gives the material the appearance of marine coral, hence the term nanocoral. (C) 2016 Elsevier B.V. All rights reserved.
22.	Carlberg, Björn, 1983, et al. (author) Polymer-metal nanofibrous composite for thermal management of microsystems 2012 In: Materials Letters. - : Elsevier BV. - 1873-4979 .- 0167-577X. ; 75, s. 229-232 Journal article (peer-reviewed)abstract In this letter, a composite structure based on a porous electrospun polyimide structure infiltrated with indium aimed at thermal interface material applications is presented. A porous nanofibrous structure was prepared by electrospinning of polyimide. An interfacial nanocomposite layer of silver nanoparticles partially or fully embedded in the polyimide matrix was synthesized on the fiber surfaces, followed by autocatalytic deposition of a uniform silver coating (using the interfacial layer as an anchored seed layer) serving as a reactive wetting layer for the infiltrating melt. The thermal performance of the composite was evaluated and the thermal conductivity was determined to be 27 W/mK, accompanied by low contact resistance of the metallurgical bond (
23.	Carlström, Ingeborg, et al. (author) Cross-linked gelatin-nanocellulose scaffolds for bone tissue engineering 2020 In: Materials letters (General ed.). - : Elsevier B.V.. - 0167-577X .- 1873-4979. ; 264 Journal article (peer-reviewed)abstract Wood-based cellulose nanofibrils (CNFs) have, in addition to high specific surface area and high surface reactivity, ability to mimic nanostructured collagen in bone extracellular matrix. These properties make CNFs promising materials for bone tissue engineering (BTE). The CNFs degrade slowly in vivo. By blending and cross-linking gelatin (Gel) with CNFs, scaffolds were produced with tuned degradation rate and enhanced mechanical properties, more suitable for BTE applications. This in vitro study aimed to examine initial biological responses of human bone marrow mesenchymal stem cells to cross-linked Gel-CNF scaffolds. The scaffolds were fabricated from 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-oxidized CNF blended with Gel and cross-linked either by dehydrothermal treatment (DHT) or by a combination of hexamethylenediamine, genipin, and DHT. CNF scaffolds without cross-linking served as control. The produced scaffolds supported cell attachment, spreading, and osteogenic differentiation. However, the early cell attachment after 1 day and the expression of RUNX2 and SPP1 genes after 7 days were highest in the CNF scaffolds. The results suggest that cross-linked Gel-CNF are cytocompatible and holds potential for BTE applications.
24.	Chen, Song, et al. (author) Highly repeatable synthesis of nHA with high aspect ratio 2015 In: Materials letters (General ed.). - : Elsevier BV. - 0167-577X .- 1873-4979. ; 159, s. 163-167 Journal article (peer-reviewed)
25.	Choi, J H, et al. (author) Comparative study on dry etching of alpha- and beta-SiC nano-pillars 2012 In: Materials letters (General ed.). - : Elsevier. - 0167-577X .- 1873-4979. ; 87, s. 9-12 Journal article (peer-reviewed)abstract Different polytypes (alpha-SiC and beta-SiC) and crystallographic orientations ((0001) and (11-20) of 6H-SiC) have been used in order to elaborate silicon carbide (SiC) nanopillars using the inductively coupled plasma etching method. The cross section of the SiC pillars shows a rhombus, pentagonal or hexagonal morphology depending on polytypes and crystallographic orientations. The favored morphologies of SiC nanopillars originate from a complex interplay between their polytypes and crystal orientations, which reflects the so-called Wulffs rule.
26.	Davoodi, M.M., et al. (author) Effect of polybutylene terephthalate (PBT) on impact property improvement of hybrid kenaf/glass epoxy composite 2012 In: Materials letters (General ed.). - : Elsevier BV. - 0167-577X .- 1873-4979. ; 67:1, s. 5-7 Journal article (peer-reviewed)abstract Environmental regulations, costs and lightweight encourage car manufacturers to develop new reliable products. Epoxy provides a reliable fibre impregnation and creates substantial three-dimensional (3D) cross-linking for proper load transmission and impact strength improvement, but their low toughness decreases their energy absorption. Thermoplastic toughening improves the epoxy impact property with a low thermo-mechanical defect. This study, focused on improving the impact property of hybrid kenaf/glass fibre epoxy composite by use of a modified sheet moulding compound (GMT). The results indicated that most of the mechanical properties of developed material were almost the same as those of the GMT, except impact. This result highlights the potential for utilisation of the toughened hybrid bio-composite in some automotive structural components. Moreover, geometric parameters, e.g., cross-section, thickness, and reinforcement ribs suggest an improvement of structural impact resistance to comply with the bumper beam product design specification (PDS).
27.	Dhage, S. R., et al. (author) Fabrication of CIGS thin film absorber by laser treatment of pre-deposited nano-ink precursor layer 2014 In: Materials letters (General ed.). - : Elsevier. - 0167-577X .- 1873-4979. ; 134, s. 302-305 Journal article (peer-reviewed)abstract A process to prepare Copper Indium Gallium Selenide (CIGS) absorber thin films by laser treatment of pre-deposited nano-inks has been investigated. Two approaches were followed, one using an ink of CIGS nanoparticles and other employing an ink comprising a mixture of a CIG metallic alloy and Se nanoparticles. Laser post treatment of the film applied with the CIGS ink was found to retain the chalcopyrite structure following melting and recrystallization, with no additional phases being generated during the process. Single-phase, highly crystalline CIGS thin films were also found to result from the ink made of CuIn0.7Ga0.3 and Se nanoparticles precursor following laser treatment. The CuIn0.7Ga 0.3Se2 thin films obtained in both cases were consistent with the initial constitution of the precursor materials used in terms of the Ga/(Ga+In) ratio. The prepared films were comprehensively characterized using XRD, SEM-EDS and XRF. Results reveal that the above non-vacuum approach obviating the need for a selenization step is simple, quick and expected to have a large impact on the overall process economics for fabrication of CIGS thin film solar cells. © 2014 Elsevier B.V.
28.	Douglas, Timothy E. L., et al. (author) Pectin coatings on titanium alloy scaffolds produced by additive manufacturing : Promotion of human bone marrow stromal cell proliferation 2018 In: Materials letters (General ed.). - : Elsevier BV. - 0167-577X .- 1873-4979. ; 227, s. 225-228 Journal article (peer-reviewed)abstract Ti6Al4V is a popular biomaterial for load-bearing implants for bone contact, which can be fabricated by additive manufacturing technologies. Their long-term success depends on their stable anchoring in surrounding bone, which in turn depends on formation of new bone tissue on the implant surface, for which adhesion and proliferation of bone-forming cells is a pre-requisite. Hence, surface coatings which promote cell adhesion and proliferation are desirable. Here, Ti6Al4V discs prepared by additive manufacturing (EBM) were coated with layers of pectins, calcium-binding polysaccharides derived from citrus (C) and apple (A), which also contained alkaline phosphatase (ALP), the enzyme responsible for mineralization of bone tissue. Adhesion and proliferation of human bone marrow stromal cells (hBMSC) were assessed. Proliferation after 7 days was increased by A-ALP coatings and, in particular, by C-ALP coatings. Cell morphology was similar on coated and uncoated samples. In conclusion, ALP-loaded pectin coatings promote hBMSC adhesion and proliferation.
29.	Edgren, Aina, 1995, et al. (author) Alloying of C40-structured Mo(Si,Al) 2 with Nb, Ta and V 2023 In: Materials Letters. - 1873-4979 .- 0167-577X. ; 353 Journal article (peer-reviewed)abstract Alloying of Mo(Si,Al)2, prepared by sintering, with Nb, Ta or V has been studied. All alloyed materials retained the C40-structured matrix phase of the un-alloyed reference material. The concentration of alloying elements in the C40 phase reached 0.4–1.6 at.% (approximately 20–50 % of the intended levels), and the remaining alloying content was dissolved in the minority D8m- and D88-structured (Mo,X)5(Si,Al)3 phases. V-alloying also promoted the formation of C54-structured (Mo,V)(Si,Al)2.
30.	Eivazihollagh, Alireza, et al. (author) One-pot synthesis of cellulose-templated copper nanoparticles with antibacterial properties 2017 In: Materials letters (General ed.). - : Elsevier BV. - 0167-577X .- 1873-4979. ; 187, s. 170-172 Journal article (peer-reviewed)abstract We report a facile in situ synthesis of spherical copper nanoparticles (NPs) templated by a gelled cellulose II matrix under alkaline aqueous reaction conditions. In under 20 min, the hybrid material could be obtained in a one-pot reaction. Field-emission scanning electron microscopy (FE-SEM) revealed that the polycrystalline NPs of 200–500 nm were well distributed in the regenerated cellulose matrix. The average Cu crystallite size was of the order of 20 nm, as estimated from both X-ray diffraction (XRD) and FE-SEM. XRD data also indicated that the composite contained up to approximately 20% Cu2O. In suspensions containing the hybrid material, growth of Escerichia coli and Staphylococcus aureus strains was inhibited by 80% and 95%, respectively, after 72 h. The synthesis procedure offers a general approach to designing various low-cost hybrid materials of almost any shape, and the concept could be extended to utilization areas such as catalysis, functional textiles, and food packaging as well as to electronic applications.
31.	Engström, Andreas, et al. (author) Synthesis of a TiCN – SiC polyhedron and elongated crystals nanopowder at low nitrogen concentration 2012 In: Materials letters (General ed.). - : Elsevier BV. - 0167-577X .- 1873-4979. ; 81, s. 148-150 Journal article (peer-reviewed)abstract At room temperature diluted TiCl4 and CCl4 were reduced by sodium particles and mixed with a polycarbomethylsilane (PCS) solution to yield a precursor. It was dried and subsequently annealed at 1300 °C, 1400 °C and 1450 °C in a tube furnace using argon with 10 ppm N2. After the 1450 °C annealing a nanocrystalline powder of TiC0.5 N0.5–SiC polyhedron and elongated crystals was obtained. At the low nitrogen concentration during annealing a gradual nitration is proposed. It is promoted by carbon gaseous species, precursor oxidation, a sufficient temperature and a summarised nitrogen surplus compared to the titanium and carbon amount.
32.	Frenning, Göran (author) Towards a mechanistic model for the interaction between plastically deforming particles under confined conditions : A numerical and analytical analysis 2013 In: Materials letters (General ed.). - : Elsevier BV. - 0167-577X .- 1873-4979. ; 92, s. 365-368 Journal article (peer-reviewed)abstract Triaxial compression of plastically deforming particles was studied with the finite element method in order to identify the mechanisms that underlie the particle response under confined conditions. In addition to the established elastoplastic behaviour at small and intermediate strains, the coalescence of plastic zones centred at contacts resulted in a reduced stiffness, whereas a significantly increased stiffness was seen once the material displaced by plastic deformation filled the ambient void space, signifying the onset of a stage dominated by elastic volume reduction. Moreover, an analytical model for multiple simultaneous contacts was formulated, assuming that the deformed particle shape could be approximated by a truncated sphere and that the behaviour of each individual contact could be described in terms of a hardness. The thus obtained model exhibited a promising agreement with the numerical results.
33.	Fu, Yifeng, 1984, et al. (author) Selective growth of double-walled carbon nanotubes on gold films 2012 In: Materials Letters. - : Elsevier BV. - 1873-4979 .- 0167-577X. ; 72, s. 78-80 Journal article (peer-reviewed)abstract Growth of high-quality vertical aligned carbon nanotube (CNT) structures on silicon supported gold (Au) films by thermal chemical vapor deposition (TCVD) is presented. Transmission electron microscopy (TEM) images show that the growth is highly selective. Statistical study reveals that 79.4% of the as-grown CNTs are double-walled. The CNTs synthesized on Au films are more porous than that synthesized on silicon substrates under the same conditions. Raman spectroscopy and electrical characterization performed on the as-grown double-walled CNTs (DWNTs) indicate that they are competitive with those CNTs grown on silicon substrates. Field emission tests show that closed-ended DWNTs have lower threshold field than those open-ended.
34.	Fu, Yifeng, 1984, et al. (author) Thick film patterning by lift-off process using double-coated single photoresists 2012 In: Materials Letters. - : Elsevier BV. - 1873-4979 .- 0167-577X. ; 76, s. 117-119 Journal article (peer-reviewed)abstract A novel method using lift-off process for patterning very thick materials is developed and demonstrated. Unlike conventional lift-off processes, no special lift-off resist is used in this method. Instead, only a double-coated single photoresist is needed. Demonstrations using two commercial photoresists show that good patterning morphology and obvious undercuts as high as 15 mu m are obtained for lift-off, which is very difficult to achieve by existing methods. The application and feasibility of this approach is demonstrated by a carbon nanotube transfer process. This simple and effective method offers wider option to pattern very thick materials in high quality which are in strong demands.
35.	Gault, B., et al. (author) Atom probe microscopy characterization of as quenched Zr-0.8 wt% Fe and Zr-0.15 wt% Cr binary alloys 2013 In: Materials letters (General ed.). - : Elsevier BV. - 0167-577X .- 1873-4979. ; 91, s. 63-66 Journal article (peer-reviewed)abstract Two binary Zr-alloys with a β-quenched structure were analysed by atom probe tomography to provide a better understanding of how Fe and Cr perform in industrial Zr alloys. In a Zr-0.8 Fe (wt%) alloy, we observed a dispersion of precipitates with a composition close to Zr3Fe, and Fe segregated to a grain boundary. In a Zr-0.15 Cr (wt%) alloy, Cr was observed in solid solution in the Zr-matrix and segregated to grain boundary where it formed small spherical particles or elongated atmospheres.
36.	Ghatei-Kalashami, A., et al. (author) Liquid metal embrittlement cracking behavior in iron-zinc (Fe/Zn) couple : Comparison of ferritic and austenitic microstructures 2022 In: Materials letters (General ed.). - : Elsevier. - 0167-577X .- 1873-4979. ; 324 Journal article (peer-reviewed)abstract Liquid metal embrittlement (LME) has emerged as a major concern when developing high-strength automotive steels. However, information regarding the impact of initial microstructure on LME severity is limited in the Fe/Zn couple. Specifically, there is no consensus as to which ferritic and austenitic microstructures are more susceptible to LME cracking. The present study aims to examine the LME cracking behavior of fully ferritic and austenitic microstructures under the same thermomechanical conditions. It was shown that the ferritic microstructure has a higher sensitivity to LME crack initiation, whereas the austenitic specimen displayed a much longer average crack length, which indicates higher crack propagation rate than the ferritic specimen. It has been determined that in-situ austenite to ferrite transformations during Zn diffusion, as well as grain boundary segregation of alloying elements such as Cr and Ti, contribute to the LME propagation rate.
37.	Glezer, A. M., et al. (author) Pinning of nanocrystals growth at Fe-Ni-B amorphous alloy crystallization: Atom probe investigations 2015 In: Materials Letters. - : Elsevier BV. - 1873-4979 .- 0167-577X. ; 160, s. 339-342 Journal article (peer-reviewed)abstract The crystallization processes in Fe50Ni33B17 amorphous alloy have been investigated by transmission electron microscopy (TEM) and a three dimensional atom probe (3DAP). The γ-Fe,Ni FCC crystals, 25 nm in size, were found in the amorphous alloy annealed at temperatures ranging 360-400 °C for 1 h. TEM demonstrates that the nanocrystals growth stops as the temperature rises. The formation of an amorphous layer enriched in boron at the border of γ-Fe,Ni nanocrystals responsible for the pinning of nanocrystals size was observed by 3DAP. The composition of an amorphous barrier by 3DAP was found to be Fe50Ni29B21. It was proposed that this composition reveals higher crystallization temperature, which is the reason of pinning nanocrystals growth.
38.	Han, Hoang Van, et al. (author) Single-crystal zinc oxide nanorods with nanovoids as highly sensitive NO2 nanosensors 2013 In: Materials letters (General ed.). - : Elsevier BV. - 0167-577X .- 1873-4979. ; 94, s. 41-43 Journal article (peer-reviewed)abstract Design and synthesis of nanostructured materials with a highly porous crystal structure and high specific surface area are the key issues to an enhanced gas sensing performance. This letter introduces a simple and scalable hydrothermal method to fabricate single-crystal ZnO nanorods (NRs) with nanovoids (NVs) for highly sensitive NO2 nanosensors. The fabricated ZnO NRs have a single-crystal structure with an average length and diameter of about 900 nm and 23 nm, respectively. NVs of less than 5 nm size are found frequently along the NRs. Gas-sensing characterizations revealed that the ZnO NR sensors exhibited a relatively high response to sub-ppm NO2 with excellent stability after 8 cycles of switching from NO2 to dry air without significant response reduction.
39.	Hedberg, Yolanda, et al. (author) Size matters : Mechanism of metal release from 316L stainless steel particles is governed by size-dependent properties of the surface oxide 2014 In: Materials letters (General ed.). - : Elsevier BV. - 0167-577X .- 1873-4979. ; 122, s. 223-226 Journal article (peer-reviewed)abstract Size-dependent health aspects due to exposure to micro- or nano-sized particles can only be fully understood if their physicochemical properties are well characterized. The aim of this study was to explain the process of metal release from well-characterized inert gas atomized stainless steel 316L particles, sized < 4 gm (fine) and < 45 gm (coarse), in aggressive environments of relevance for inhalation and cellular uptake. This was accomplished by correlating new results from real-time metal release measurements with particle- and surface oxide characteristics. In simulated biological media with complexing properties, a complexation (ligand)-induced dissolution mechanism is dominating the metal release from fine 316L particles (having a homogeneous and amorphous Mn-rich surface oxide due to rapid cooling). At similar conditions, the coarse 316L particles show a metal release mechanism dominated by fast dissolution of surface oxide nanoparticles (rich in Mn, Fe, and some S), acting as initiation sites for metastable pitting corrosion.
40.	Hedberg, Yolanda, et al. (author) Ultrafine 316 L stainless steel particles with frozen-in magnetic structures characterized by means of electron backscattered diffraction 2011 In: Materials letters (General ed.). - : Elsevier BV. - 0167-577X .- 1873-4979. ; 65:14, s. 2089-2092 Journal article (peer-reviewed)abstract Electron Backscatter Diffraction (EBSD) studies clearly revealed a different crystallographic structure of the smallest particle size fraction of gas-atomized AISI 316 L stainless steel powder (<4 mu m) compared with larger sized fractions of the same powder (<45 mu m). Despite similar chemical compositions, the predominating structure of the smallest particle size fraction was ferritic (i.e., has ferromagnetic properties) whereas the larger sized particle fractions and massive 316 L revealed an expected austenitic and non-magnetic structure. From these findings, it follows that direct magnetic separation can be applied to separate very fine sized particles. These structural differences explain previously observed dissimilarities from corrosion and metal release perspectives.
41.	Hedström, Peter, et al. (author) Elastic strain evolution and ε-martensite formation in individual austenite grains during in situ loading of a metastable stainless steel 2008 In: Materials letters (General ed.). - : Elsevier BV. - 0167-577X .- 1873-4979. ; 62:2, s. 338-340 Journal article (peer-reviewed)abstract The (hcp) ε-martensite formation and the elastic strain evolution of individual (fcc) austenite grains in metastable austenitic stainless steel AISI 301 has been investigated during in situ tensile loading up to 5% applied strain. The experiment was conducted using high-energy X-rays and the 3DXRD technique, enabling studies of individual grains embedded in the bulk of the steel. Out of the 47 probed austenite grains, one could be coupled with the formation of ε-martensite, using the reported orientation relationship between the two phases. The formation of ε-martensite occurred in the austenite grain with the highest Schmid factor for the active {111}b12¯1N slip system.
42.	Hens, Philip, et al. (author) Sublimation growth of thick freestanding 3C-SiC using CVD-templates on silicon as seeds 2012 In: Materials letters (General ed.). - : Elsevier. - 0167-577X .- 1873-4979. ; 67:1, s. 300-302 Journal article (peer-reviewed)abstract Cubic silicon carbide is a promising material for medium power electronics operating at high frequencies and for the subsequent growth of gallium nitride for more efficient light emitting diodes. We present a new approach to produce freestanding cubic silicon carbide (3C-SiC) with the ability to obtain good crystalline quality regarding increased domain size and reduced defect density. This would pave the way to achieve substrates of 3C-SiC so that the applications of cubic silicon carbide material having selectively (111) or (001) oriented surfaces can be explored. Our method is based on the combination of the chemical vapor deposition method and the fast sublimation growth process. Thin layers of cubic silicon carbide grown heteroepitaxially on silicon substrates are for the first time used for a subsequent sublimation growth step to increase layer thicknesses. We have been able to realize growth of freestanding (001) oriented 3C-SiC substrates using growth rates around 120 μm/h and diameters of more than 10 mm. The structural quality from XRD rocking curve measurements of (001) oriented layers shows good FWHM values down to 78 arcsec measured over an area of 1 × 2 mm2, which is a quality improvement of 2–3 times compared with other methods like CVD.
43.	Herrera, Martha, et al. (author) Comparison of cellulose nanowhiskers extracted from industrial bio-residue and commercial microcrystalline cellulose 2012 In: Materials letters (General ed.). - : Elsevier BV. - 0167-577X .- 1873-4979. ; 71:1, s. 28-31 Journal article (peer-reviewed)abstract The aim of this work was to compare the physical and chemical properties of cellulose nanowhiskers extracted from industrial bio-residue (CNW-BR) by homogenization, and microcrystalline cellulose (CNW-MCC) by acid hydrolysis. CNW-MCC showed a higher surface charge than CNW-BR when analyzed using conductometric titration. Both CNW-suspensions showed flow birefringence, indicating the presence of individualized whiskers. Morphology study confirmed that the whisker diameters were less than 10 nm for both materials, and atomic force microscope images showed somewhat more aggregated BR nanowhiskers. UV/Vis spectroscopy of the CNW-films showed transparency in visual light. The relative crystallinity obtained from X-ray diffraction was 77% for the CNW-BR, and 85% for the CNW-MCC. It was demonstrated, by thermal analysis, that the CNW-BR was more thermally stable than the CNW-MCC, having a higher degradation onset temperature (218 °C and 155 °C) as well as maximum degradation temperature.
44.	Hossain, SK Saddam, et al. (author) Fabrication of lightweight ceramics of complex geometries in freezing weather 2024 In: Materials letters (General ed.). - : Elsevier B.V.. - 0167-577X .- 1873-4979. ; 368 Journal article (peer-reviewed)abstract Natural freezing weather is used to fabricate lightweight ceramic monoliths with aligned pores for the first time. A stable aqueous-based alumina slurry (16 vol%) was formulated and frozen at −10 to −25 °C in natural freezing environment. The thermally treated ceramic monoliths achieved ∼82–88 vol% porosity with short-range aligned pores. Finally, the unidirectional pores in the structure are achieved using a mold with thermal insulation properties. Natural freezing saves 300 kJ of energy per kg of alumina slurry. Mechanically stable lightweight porous ceramics with complex geometries can be designed without cryogenic fluids, refrigeration, or thermal baths. Implementing natural freezing in the porous ceramics industries, particularly in the Arctic region, will bring forward a sustainable approach by reducing energy consumption and CO2 emissions.
45.	Hu, Jing, et al. (author) Hydrothermal preparation of boehmite-doped AgCl nanocubes and their characterization 2011 In: Materials letters (General ed.). - : Elsevier BV. - 0167-577X .- 1873-4979. ; 65:11, s. 1531-1534 Journal article (peer-reviewed)abstract A simple hydrothermal route to the preparation of the boehmite-doped AgCl nanocubes using AgNO3,AlCl3 center dot 6H(2)O and NaOH at 200 degrees C for 24 h is reported. The products were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectrometry (FT-IR), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), UV-vis, thermogravimetric analysis (TGA), and differential thermal analysis (DTA). FE-SEM and TEM micrographs showed that the obtained boehmite-doped AgCl had nanocube-like morphology. The influence of heating temperature on the phase, microstructure, morphology, and thermal stability of the products were also investigated. UV-visible results indicated that the absorption edge moved to higher wavelength with the increasing heating temperature. These materials would be a promising material for photocatalyst applications.
46.	Jia, Ning, et al. (author) Microwave-assisted synthesis and characterization of cellulose-carbonated hydroxyapatite nanocomposites in NaOH-urea aqueous solution 2010 In: Materials letters (General ed.). - : Elsevier BV. - 0167-577X .- 1873-4979. ; 64:20, s. 2223-2225 Journal article (peer-reviewed)abstract We report the microwave-assisted synthesis of the cellulose-carbonated hydroxyapatite (CHA) nanocomposites with CHA nanostructures dispersed in the cellulose matrix by using the cellulose solution, CaCl2, and NaH2PO4. The cellulose solution was previously prepared by the dissolution of microcrystalline cellulose in NaOH-urea aqueous solution. The influences of the heating time and cellulose concentration on the products were also investigated. The X-ray powder diffraction (XRD) and Fourier transform infrared spectrometry (FT-IR) results indicated that the obtained products were the cellulose-CHA nanocomposites. The scanning electron microscopy (SEM) micrographs showed the CHA nanostructures were dispersed in the cellulose matrix. The thermal stability of the cellulose-CHA nanocomposites in air was investigated using thermogravimetric analysis (TGA) and differential thermal analysis (DTA). This method is simple, fast, low-cost and suitable for large-scale production of cellulose-based nanocomposites.
47.	Jiao, Mingzhi, et al. (author) On-chip hydrothermal growth of ZnO nanorods at low temperature for highly selective NO2 gas sensor 2016 In: Materials letters (General ed.). - : Elsevier BV. - 0167-577X .- 1873-4979. ; 169, s. 231-235 Journal article (peer-reviewed)abstract ZnO nanorods were selectively grown on-chip with a two-step low-temperature hydrothermal method and their gas sensing properties were investigated. Small zinc islands were deposited by sputtering on a glass substrate and used as nucleation sites for the ZnO nanorod growth. An equimolar aqueous solution of 0.005 M Zn(NO3)(2)center dot 6H(2)O and (CH2)(6)N-4 at 85 center dot C was used in two steps. The first step was used for nucleation and growth of short ZnO nanorods for 4 h, whereas the second step was used for elongation of the nanorods for 36 h. Long porous nanorods from neighboring islands connected to each other and formed nanorod junctions. A gas sensor with such nanorods was evaluated towards NO2, ethanol, hydrogen, and ammonia to characterize its sensing properties. It showed that the gas sensor has the highest sensitivity to NO2, and a very high selectivity to this gas when measured at 450 degrees C.
48.	Jiao, Xinjang, et al. (author) Hierarchical porous TiAl3 intermetallics synthesized by thermal explosion with a leachable space-holder material 2016 In: Materials letters (General ed.). - : Elsevier BV. - 0167-577X .- 1873-4979. ; 181, s. 261-264 Journal article (peer-reviewed)abstract Porous TiAl3 intermetallics were synthesized by thermal explosion (TE) reaction with NaCl as space holder material, from Ti-75Al at.% elemental powders. Results showed that the actual temperature of specimen climbed rapidly from 667 °C to 1106 °C. As a consequence, porous TiAl3 intermetallics with high open porosity (>80%) can be easily achieved when adding NaCl particles above 50 vol%. XRD patterns showed that only single-phase TiAl3 compound was synthesized via TE. Hierarchical porous TiAl3 materials displayed three pore structures, including large pores replicating from original NaCl particles, small pores among the skeletons, and tiny pores precipitated from particle skeletons. Moreover, porous TiAl3 intermetallics exhibited a uniform pore size distribution and formed an open-cellular structures allowing for the liquid-gas separation and filtration applications
49.	Johansson, Emma, et al. (author) Synthesis and characterization of large mesoporous silica SBA-15 sheets with ordered accessible 18 nm pores 2009 In: Materials Letters. - : Elsevier BV. - 0167-577X. ; 63:24-25, s. 2129-2131 Journal article (peer-reviewed)abstract Mesoporous silica SBA-15 in the form of 10-30 μm sized sheets with unusually large ordered pores has been synthesized using heptane as a cosolvent in the presence of NH4F. The resulting morphology of 400 nm thick sheets that contain easily accessed, hexagonally arranged, 18 nm sized pores running parallel to sheet normal has not been previously reported. The material has a BET surface area of 541 m2/g, large pore volume of 1.69 cm3/g and ordered mesopore structure with a narrow pore size distribution around 18 nm. A mechanism for sheet formation based on heptane droplets acting as sites for self assembling of silica crystallites is suggested.
50.	Kapilashrami, Mukes, et al. (author) Coexistence of ultraviolet photo-response and room-temperature ferromagnetism in polycrystalline ZnO thin films 2010 In: Materials letters (General ed.). - : Elsevier BV. - 0167-577X .- 1873-4979. ; 64:11, s. 1291-1294 Journal article (peer-reviewed)abstract The coexistence of ultraviolet (UV) photoconductivity (PC) and room-temperature ferromagnetism (RTFM) is observed in polycrystalline ZnO thin films deposited by unbalanced magnetron sputtering under high oxygen pressure. A significant increase in PC (similar to 870% to 40000%) is observed with increasing film thickness and the consequent structural disorder and film porosity. In contrast, the saturation magnetization (M(S)) at room temperature is found to decrease from 1.02 emu/g to 0.53 emu/g with increasing film thickness from 50 to 150 nm.

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