Articles de revues : « Dense and porous structure »

1

Zhang, Fa Ming, Jiang Chang, Jian Xi Lu et Kai Li Lin. « Fabrication and Mechanical Properties of Dense/Porous β-Tricalcium Phosphate Bioceramics ». Key Engineering Materials 330-332 (février 2007) : 907–10. http://dx.doi.org/10.4028/www.scientific.net/kem.330-332.907.

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Attempt to increase the mechanical properties of porous bioceramics, a dense/porous structured β-TCP bioceramics that mimic the characteristics of nature bone were fabricated. Experimental results show that the dense/porous structured β-TCP bioceramics demonstrated excellent mechanical properties with compressive strength up to 74 MPa and elastic modulus up to 960 MPa, which could be tailored by the dense/porous cross-sectional area ratio obeying the rule of exponential growth. The interface between the dense and porous bioceramics is connected compactly and tightly with some micropores distributed in the matrix of both porous and dense counterparts. The dense/porous structure of β-TCP bioceramics may provide an effective way to increase the mechanical properties of porous bioceramics for bone regeneration at weight bearing sites.

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Su, Ya Yu, Xiao Lei Li, Hui Jie Tang, Zhi Hao Zhao et Jian He. « Thermal Shock Behavior and Bonding Strength of MoSi₂-BaO-Al₂O₃-SiO₂ Gradient Porous Coating with Polymethyl Methacrylate Addition for Porous Fibrous Insulations ». Solid State Phenomena 281 (août 2018) : 493–98. http://dx.doi.org/10.4028/www.scientific.net/ssp.281.493.

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In order to improve the thermal shock behavior of high temperature resistant coating on porous fibrous referactory insulations, the MoSi2-BaO-Al2O3-SiO2(MoSi2-BAS) gradient porous coatings were designed by preparing a dense surface layer and a porous bonding layer with the method of brushing and subsequent sintering at 1773 K. The porous bonding layer was obtained by adding polymethyl methacrylate (PMMA) as pore former. As the content of PMMA increases, the MoSi2-BAS coatings changed from a dense structure into a gradient porous structure. The interface bonding strength and thermal shock resistance of the MoSi2-BAS coatings were investigated. The result shows that the as-prepared coating with gradient porous structure exhibited excellent thermal shock resistance, which remained gradient structure without cracking after thermal cycling 100 times between 1773 K and room temperature. And the interface bonding strength of the gradient porous coating reached 1.5±0.08 Mpa, which was much better than that of the dense coating.

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Lee, Eunji, Woomi Gwon et Sangwoo Ryu. « Nucleation and Growth-Controlled Morphology Evolution of Cu Nanostructures During High-Pressure Thermal Evaporation ». Korean Journal of Metals and Materials 59, n^o 2 (5 février 2021) : 135–41. http://dx.doi.org/10.3365/kjmm.2021.59.2.135.

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The formation of porous material structures has been widely investigated for the development of high-performance energy materials, catalysts, and chemical sensing devices. Various nanoporous structure fabrication methods are based on wet-chemical processes, which require precise control of the process parameters. Physical vapor deposition such as thermal evaporation utilizes high vacuum so that the deposition process is relatively simple, free of contamination, and easily reproduced. However, because of the long mean-free-path of the evaporated atoms in high vacuum, heterogeneous nucleation and the growth of adatoms occurs on the substrate surface, which results in the formation of dense and compact thin films. But by changing the working pressure, various morphologies of porous nanostructures can be obtained. As applied to copper, with increasing pressure the thin film evolves from a dense structure to a coral-like nanoporous structure through a porous columnar structure. All of the porous structures consist of nanoparticle aggregates, where copper nanoparticles are connected to each other, and many nano-gaps are found inside the aggregates. A surface plasmonic effect is expected. The porous copper nanostructured films demonstrated high surfaceenhanced Raman spectroscopy activity.

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Maîtrejean, Guillaume, Patrick Terriault et Vladimir Brailovski. « Density Dependence of the Macroscale Superelastic Behavior of Porous Shape Memory Alloys : A Two-Dimensional Approach ». Smart Materials Research 2013 (19 septembre 2013) : 1–13. http://dx.doi.org/10.1155/2013/749296.

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Porous Shape Memory Alloys (SMAs) are of particular interest for many industrial applications, as they combine intrinsic SMA (shape memory effect and superelasticity) and foam characteristics. The computational cost of direct porous material modeling is however extremely high, and so designing porous SMA structure poses a considerable challenge. In this study, an attempt is made to simulate the superelastic behavior of porous materials via the modeling of fully dense structures with material properties modified using a porous/bulk density ratio scaling relation. Using this approach, direct modeling of the porous microstructure is avoided, and only the macroscale response of the model is considered which contributes to a drastic reduction of the computational cost. Foam structures with a gradient of porosity are also studied, and the prediction made using the fully dense material model is shown to be in agreement with the mesoscale porous material model.

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Arnaud, Gwendoline, Vincent Rey, Julien Touboul et Damien Sous. « Wave Propagation Through Dense Vertical Cylinder Arrays : 3D Experimental Study ». International Journal of Ocean and Coastal Engineering 02, n^o 01n02 (mars 2019) : 1950001. http://dx.doi.org/10.1142/s2529807019500015.

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The purpose of this research work is to study the diffraction of surface gravity waves propagating through rectangular porous medium in three dimensions. The considered porous structure consists of dense arrays of surface piercing vertical cylinders. Experiments for different regular wave conditions have been carried out, especially for three-wave frequencies. The experimental data of wave refraction–diffraction and reflection have been compared to computed results from potential linear theory solved with an integral matching method. Comparison with a previous 2D study about wave propagation through porous medium in a 10 m long wave flume is also discussed in order to highlight the refraction–diffraction effect due to the porous structure.

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Li, Yuan, Ji Qiang Gao, Jian Feng Yang, Hong Jie Wang et Guan Jun Qiao. « Fabrication of SiC Dense-Porous Laminates by Electrophoretic Deposition Process ». Key Engineering Materials 368-372 (février 2008) : 1841–43. http://dx.doi.org/10.4028/www.scientific.net/kem.368-372.1841.

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In order to obtain dense-porous laminated structure in green bodies of SiC ceramics, rapid aqueous electrophoretic deposition (EPD) was introduced. The suspension for the electrophoretic deposition was prepared using silicon carbide, silicon and carbon powders as the starting materials. During the electrophoretic deposition process, the intending dense and porous layers were deposited alternately to form the green body. After drying, the green bodies were reaction-bonded at 1550°C in vacuum atmosphere. Pore fraction of the porous layers could be adjusted by changing process preferences of EPD and suspension composition. Pore size and size distribution could be controlled by using different sized starting powders. Using this process, no additional substance is necessary to generate the pores via burnt-off, and the dense/porous laminated structure can be obtained by one-step sintering process.

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Choi, Youngbin, Keeyoung Jung, Hyeong-Jun Kim, Ji-Woong Moon et Jong-Won Lee. « Lithium–oxygen batteries with triplex Li+-selective solid membranes ». Chemical Communications 55, n^o 53 (2019) : 7643–46. http://dx.doi.org/10.1039/c9cc03652k.

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Han, Jae-Yun, Chang-Hyun Kim, Sang-Ho Kim et Dong-Won Kim. « Development of Pd Alloy Hydrogen Separation Membranes with Dense/Porous Hybrid Structure for High Hydrogen Perm-Selectivity ». Advances in Materials Science and Engineering 2014 (2014) : 1–10. http://dx.doi.org/10.1155/2014/438216.

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For the commercial applications of hydrogen separation membranes, both high hydrogen selectivity and permeability (i.e., perm-selectivity) are required. However, it has been difficult to fabricate thin, dense Pd alloy composite membranes on porous metal support that have a pore-free surface and an open structure at the interface between the Pd alloy films and the metal support in order to obtain the required properties simultaneously. In this study, we fabricated Pd alloy hydrogen separation membranes with dense/porous hybrid structure for high hydrogen perm-selectivity. The hydrogen selectivity of this membrane increased owing to the dense and pore-free microstructure of the membrane surface. The hydrogen permeation flux also was remarkably improved by the formation of an open microstructure with numerous open voids at the interface and by an effective reduction in the membrane thickness as a result of the porous structure formed within the Pd alloy films.

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Yasenchuk, Yu, N. V. Artyuhova, K. V. Almaeva, A. S. Garin et V. E. Gunther. « Segregation in Porous NiTi Made by SHS in Flow Reactor ». KnE Materials Science 2, n^o 1 (17 juillet 2017) : 168. http://dx.doi.org/10.18502/kms.v2i1.793.

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The research considers the contribution of gases to the surface formation during self-propagating high-temperature synthesis (SHS) of porous titanium nickelide based alloys. The structure of the obtained porous alloys was analyzed using the methods of secondary ion mass spectrometry (SIMS), optical microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Nanocrystalline intermetallic oxycarbonitrides of a complicated structure were found on the porous titanium nickelide surface. A dense double gradient layer was found under the outer loose deposits. It is concluded that the dense gradient layer of intermetallic oxycarbonitride provides chemical passivity of the investigated porous alloys. Loose surface deposits of intermetallic oxycarbonitrides ensure successful integration of the alloy into the biological tissue in case of implantation.

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Zhao, Yanjing, Jiwang Jiang, Yiqing Dai, Lan Zhou et Fujian Ni. « Thermal Property Evaluation of Porous Asphalt Concrete Based on Heterogeneous Meso-Structure Finite Element Simulation ». Applied Sciences 10, n^o 5 (2 mars 2020) : 1671. http://dx.doi.org/10.3390/app10051671.

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Porous asphalt concrete (PAC) can obviously improve vehicle driving safety on rainy days and reduce environmental noise. It has been widely used in China. The existence of a large number of interconnected voids in PAC makes a significant difference in heat transfer and temperature distribution from conventional dense-graded asphalt concretes (AC). In this paper, the internal structure images of three dense-graded asphalt mixtures and one PAC were obtained by X-ray CT scanning technology, and the internal meso-structure finite element simulation models of asphalt mixtures were established by using the mapped meshing method. The temperature variations of asphalt mixture specimens during laboratory cooling and heating processes were simulated in this study, and laboratory tests were carried out to verify the simulation accuracy. Due to the simulation results, it was found that the thermal characteristics of the PAC mixture were different from those of the dense-graded asphalt mixture due to the large interconnected air void content in the PAC mixture. The temperature field in the PAC mixture was more sensitive to ambient air temperature under laboratory conditions. Moreover, in PAC specimens, temperature distributed more unevenly than in dense-grade asphalt mixtures. Therefore, it is necessary to consider the internal meso-structure of porous asphalt mixtures while simulating the temperature field in PAC specimens or pavement structures.

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Shi, Jing Yu, Matthew L. Mottern, Krenar Shqau et Henk Verweij. « Nanostructured Ceramic Thin Films and Membranes by Wet Chemical Processing Methods ». Advances in Science and Technology 45 (octobre 2006) : 1252–59. http://dx.doi.org/10.4028/www.scientific.net/ast.45.1252.

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Nanostructured ceramic thin films and membranes are used for protective or functional purposes and prepared on dense or porous substrate materials. Wet chemical methods enable cheap, low-temperature, mass-scale manufacturing routes. They produce fine-grained porous and dense micro-structures that cannot be realized otherwise. In wet-chemical processing, clean nanoparticle dispersions are deposited on the substrate at, primarily, ambient conditions. The deposition is followed by a (rapid) thermal processing treatment to remove liquids and organic additives, to convert precursors to the target composition, and to establish the final porous and dense micro-structure. In the synthesis of precursor dispersions it is very important to obtain nanoparticles with a near-isometric shape and a fairly narrow particle size distribution, without the formation of secondary (agglomerate) structures. In particular the latter requires careful control of solution and interfacial chemistry to achieve proper colloidal stability, during and after the synthesis process. Characterization of coating integrity, defect morphology and defect population is done by decoration methods, microscopy, ellipsometry and statistical methods that employ membrane transport properties.

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Negro, E., M. Dieci, D. Sordi, K. Kowlgi, M. Makkee et G. J. M. Koper. « High yield, controlled synthesis of graphitic networks from dense micro emulsions ». Chem. Commun. 50, n^o 80 (2014) : 11848–51. http://dx.doi.org/10.1039/c4cc05455e.

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We propose a new synthesis method to produce hyper-branched carbon nano structures that we call carbon nano networks. These porous, graphitic materials directly grow into a networked structure, do not require the use of an inorganic support, and can be tailored by experimental conditions to better suit their application.

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Pulyalina, Alexandra, Maksim Tataurov, Ilya Faykov, Valeriia Rostovtseva et Galina Polotskaya. « Polyimide Asymmetric Membrane vs. Dense Film for Purification of MTBE Oxygenate by Pervaporation ». Symmetry 12, n^o 3 (9 mars 2020) : 436. http://dx.doi.org/10.3390/sym12030436.

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Membrane properties are determined by their morphology, which may be symmetric (dense) or asymmetric (dense/porous). Two membrane types based on the poly[(4,4′-oxydiphenylene)pyromelliteimide] (symmetric dense and asymmetric dense/porous) were prepared for a comparative study of morphology, physical properties, and transport characteristics in the pervaporation of methanol/MTBE mixture over a wide range of concentrations including the azeotropic composition. The asymmetric membrane is a good example of improving the transport properties of the polyimide by creating structure composed of a thin dense top layer on the surface of sponge-like microporous substrate. It was found that the use of the asymmetric membrane allows increasing the total flux in separation of azeotropic mixture by 15 times as compared with the dense membrane.

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Wang, Congyu, Baoyu Sun, Yongdi Zhang, Congwei Wang et Guang Yang. « Design of a Novel Trabecular Acetabular Cup and Selective Laser Melting Fabrication ». Materials 15, n^o 17 (4 septembre 2022) : 6142. http://dx.doi.org/10.3390/ma15176142.

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The acetabular cups used in total hip arthroplasty are mostly made of dense metal materials with an elastic moduli much higher than that of human bone. This leads to stress shielding after implantation, which may cause aseptic loosening of the implant. Selective laser melting (SLM) technology allows us to produce tiny and complex porous structures and to reduce the elastic moduli of dense metals, thereby avoiding stress shielding. In the present study, rhombic dodecahedron porous structures with cell sizes of 1 mm, 1.5 mm, and 2 mm were designed. The strut diameter was changed to ensure that the porosity and pore size would meet the bone ingrowth requirements. Then, porous Ti6Al4V alloy specimens were printed using SLM, and compressive tests were carried out. The results showed that the compressive strength and elastic modulus values of the specimens with a cell size of 1.5 mm were in the range of 78.16–242.94 MPa and 1.74–4.17 GPa, respectively, which are in line with the mechanical properties of human cortical bone. Finite element analysis of a total hip joint model was carried out to simulate gait, and the surface of the trabecular acetabular cup was divided into 10 regions according to the stress distribution, with the stress interval in the range of 37.44–219.24 MPa. According to the compression test results, the gradient structure of Ti6Al4V alloy with different porosity was designed for trabecular coating. The gradient porous structure meets the mechanical requirements and is closer to the natural structure of human bone than the uniformly distributed porous structure.

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Park, Jong-Hyeok, et Jin-Soo Park. « KOH-doped Porous Polybenzimidazole Membranes for Solid Alkaline Fuel Cells ». Energies 13, n^o 3 (21 janvier 2020) : 525. http://dx.doi.org/10.3390/en13030525.

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In this study the preparation and properties of potassium hydroxide-doped meta-polybenzimidazole membranes with 20–30 μm thickness are reported as anion conducting polymer electrolyte for application in fuel cells. Dibutyl phthalate as porogen forms an asymmetrically porous structure of membranes along thickness direction. One side of the membranes has a dense skin layer surface with 1.5–15 μm and the other side of the membranes has a porous one. It demonstrated that ion conductivity of the potassium hydroxide-doped porous membrane with the porogen content of 47 wt.% (0.090 S cm−1), is 1.4 times higher than the potassium hydroxide-doped dense membrane (0.065 S cm−1). This is because the porous membrane allows 1.4 times higher potassium hydroxide uptake than dense membranes. Tensile strength and elongation studies confirm that doping by simply immersing membranes in potassium hydroxide solutions was sufficient to fill in the inner pores. The membrane-electrode assembly using the asymmetrically porous membrane with 1.4 times higher ionic conductivity than the dense non-doped polybenzimidazole (mPBI) membrane showed 1.25 times higher peak power density.

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Sorokin, O. Yu, I. O. Belyachenkov, A. S. Chainikova, S. V. Zhitnyuk et P. N. Medvedev. « Structure and phase constitution of graphite-loaded reaction-bonded sic ». Voprosy Materialovedeniya, n^o 3(111) (31 octobre 2022) : 49–58. http://dx.doi.org/10.22349/1994-6716-2022-111-3-49-58.

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The influence of porous SiC preforms densities for the siliconizing process on the structure and phase constitution of graphite-loaded reaction-bonded SiC (G-SiSiC) was studied. It was found that varying the densities of porous SiC preforms containing artificial graphite of similar grain size with the dimensions less than 25 mm (in height or diameter) can lead to the G-SiSiC samples with low free Si content (less 4 wt.%.). It was also shown that reaction sintering of G-SiSiC samples with the optimized densities during the siliconizing process results in the formation of a dense fine-grained SiC layer. Moreover, during the siliconizing process, a dense SiC gradient matrix is formed in which graphite and Si inclusions are uniformly dispersed in bulk.

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Qian, Jian Gang, Chun Wang, Di Li et Yu Fen Liu. « Establishment of a Model of Growing Anodizing Film on AZ91D Mg Alloy ». Materials Science Forum 546-549 (mai 2007) : 589–92. http://dx.doi.org/10.4028/www.scientific.net/msf.546-549.589.

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The kinetics of film-forming process of anodizing on AZ91D Mg alloy have been studied through analyses of voltage-time and thickness–time curves. The surface morphology, structure, composition and valence of element, phase constituent of anodic films have been analyzed by SEM, EDS, XPS and XRD respectively. The results show that the film-forming process can be divided into four stages: I - formation of a dense layer; II - formation of a porous layer; III - fast growth of the porous layer; IV - slow growth of the porous layer. The growing process of the dense film is characterized by the rapidly formed intact and imperforate oxide film; there are few micro-cracks in partial film formed on α phase, on the contrary, intact film is formed on β phase; the forming of porous film is based on the particulate sparking product with micro-porous structure. There are two kinds of pores in the anodic film; the first one is circular or ellipse, while the second one is the irregular gaps. The dense layer is composed mainly of MgO and small amount of Al2O3, while the porous layer mainly consists of MgSiO3 and Mg3B2O6. We propose a possible model about growing anodizing film on AZ91D Mg alloy based on the experimental results.

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Brailovski, Vladimir, Patrick Terriault, Charles Simoneau, Mathieu Dumas et Bruno Jetté. « Development of a Biomimetic Metallic Femoral Stem : Methodological Approach ». Materials Science Forum 879 (novembre 2016) : 1788–93. http://dx.doi.org/10.4028/www.scientific.net/msf.879.1788.

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In this communication, a new methodological approach is proposed to develop a biomimetic metallic femoral stem. The design of this stem starts with the definition of an outer skin by reproducing the shape and overall dimensions of a Stryker® femoral stem to be implanted in an artificial femur model from Sawbones®. In-house algorithms are then used to generate two types of porous structures inside the outer skin: either a stochastic cubic-based porous structure or an ordered diamond-type porous structure. Next, a model of the femur-stem assembly is developed using the finite element method. The fully dense Stryker stem replica and two porous stems are fabricated using selective laser melting technology. Then, comparative mechanical testing is carried out using the ISO 7206-4 (2010) guidelines. These tests are conducted on an intact artificial femur (reference case) and on the identical femurs, but now implanted with the fully dense and porous stems. Using digital image correlation tools, the results of four series of tests are compared to assess which implant design leads to the lowest stress shielding in the implanted femur. Finally, the experimentally measured strain fields are compared to the numerical predictions to validate the numerical models.

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Tailor, Satish, N. Vashishtha, Ankur Modi et SC Modi. « Thermally Sprayed Porous PEEK Coating for Biomedical Implants ». Journal of Thermal Spray and Engineering 1, n^o 1 (2018) : 32–36. http://dx.doi.org/10.52687/2582-1474/116.

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The present study reports the novel results of microstructural and mechanical properties of highly porous Polyetheretherketone (PEEK) coating. PEEK is already considered as a material for biomedical implants. A new kind of approach is proposed for manufacturing of highly porous PEEK coating on a dense PEEK coating for orthopedic implants and successfully implemented to create novel biomimetic porous PEEK coating by means of thermal spray process. To imitate the structure of natural bone, as-sprayed top PEEK coating has porosity of more than 60% vol. and pore sizes of 30-80 μm. Mechanical results of dense PEEK coating show that PEEK coating exhibited good strength, hardness (20 HV0.1) and good bonding strength (15 MPa) with the metal substrate. Thermal sprayed porous PEEK coating that can be used for future implants instead of plasma sprayed titanium coating on dense PEEK implants because porous PEEK improves the bone-implant interface joining compared to plasma-sprayed titanium coating on PEEK.

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Li, Zi Fu, Chun Yu Zhang, Liu Ju Qi et Xue Tong Sun. « Selective Laser Melting Bone-Compatible Pure Titanium Porous Structure ». Applied Mechanics and Materials 423-426 (septembre 2013) : 833–36. http://dx.doi.org/10.4028/www.scientific.net/amm.423-426.833.

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In this paper the effect of selective laser melting (SLM) input energy density on densification behavior and tensile strengths of commercially pure (CP) titanium was investigated. Fully dense and high strength SLM CP titanium has been obtained. A complex bone-compatible tetrakaidecahedron based porous structure has been successfully SLM-fabricated with optimized laser parameters.

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Skripkiūnas, Gintautas, et Vitoldas Vaitkevičius. « THE INFLUENCE OF COARSE AGGREGATE CONCENTRATION ON THE STRENGTH OF CONCRETE AND ON THE POROSITY OF CONCRETE MORTAR/STAMBIOJO UŽPILDO KONCENTRACIJOS ĮTAKA BETONO STIPRUMUI IR SKIEDININĖS DALIES PORINGUMUI ». JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 7, n^o 6 (31 décembre 2001) : 446–52. http://dx.doi.org/10.3846/13921525.2001.10531771.

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The results of experiments dealing with coarse aggregate concentration influence on the concrete strength and the structure of hardened cement paste and mortar of concrete are presented in the paper. Experiments were performed on concrete with dense coarse aggregate (crushed granite) which strength is more than strength of mortar and lightweight porous aggregate (expanded clay aggregate) with strength less than that of mortar. Physical and mechanical properties of concrete with dense coarse aggregate are presented in Table 1 and the concretes with the porous coarse aggregate in Table 2. The decrease of entrained air content with the increase of coarse aggregate concentration ϕσt were determined both for concretes with dense and porous coarse aggregate. The entrained air has a significant effect on concrete strength—1% of entrained air decreases the strength of concrete about 5% [11]. The influence of the coarse aggregate concentration on the compressive strength of concrete with the constant air content is presented in Figs 3 and 4. With the increase of coarse aggregate concentration the concrete strength decreases when the entrained air content in concrete is constant. The main reasons of the concrete strength reduction are the stress concentration and structural defects near the coarse aggregate. Coarse aggregate affects the structure of mortar. Dense coarse aggregate has negligible water absorption and does not change water content in mortar of concrete, and capillary porosity of mortar remains constant when the concentration of dense coarse aggregate ϕ st increases (Fig 5). Porous coarse aggregate (expanded clay aggregate) has large water absorption (more than 16%), therefore water content in mortar of concrete is reduced and capillary porosity of mortar is significantly reduced when the concentration of porous coarse aggregate ϕ st increases (Fig 5). The entrained air content in mortar with both dense and porous coarse aggregate decreases inverse proportionally to coarse aggregate concentration ϕ st (Fig 6). The investigations have shown that suitable selection of properties and volumetric concentration of coarse aggregate can reduce stress concentration in concrete and increase the concrete strength.

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Kompan, M. E., A. E. Gorodetski et I. L. Tarasova. « Self Formation of Porous Silicon Structure : Primary Microscopic Mechanism of Pore Separation ». Solid State Phenomena 97-98 (avril 2004) : 181–84. http://dx.doi.org/10.4028/www.scientific.net/ssp.97-98.181.

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A microscopic mechanism of the self-formation of a dense pore system in the porous silicon is proposed. According to it, the process of porous silicon self-formation is dictated by the laws of dynamics for a charge carriers system. The proposed mechanism is proved by the results of computer simulation. The values of inter-pore separation distance in p-type based porous material and anodization current threshold density are evaluated; the dependence of an inter-pore separation distance on the carriers concentration, close to n-1/2, is predicted.

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Ziganshin, I. R., S. E. Porozova, A. E. Stolina et M. F. Torsunov. « Titania powder activation and rutile ceramics structure formation ». Science of Sintering 41, n^o 1 (2009) : 27–33. http://dx.doi.org/10.2298/sos0901027z.

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Impact of mechanochemical activation (MCA) in aqueous medium with various organic additives on commercial titania powder and products made of it has been investigated by X-ray diffraction, optical microscopy and Raman spectroscopy. Agar-agar additive has been shown to offer promise for activation of titania powders used in obtaining both dense and porous materials.

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Kalita, V. I., D. I. Komlev et A. A. Radiuk. « Physics, chemistry and mechanics of formation of bioactive surfaces on implants. Review ». Perspektivnye Materialy 3 (2022) : 5–23. http://dx.doi.org/10.30791/1028-978x-2022-3-5-23.

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The analysis of literature on bioactive surfaces of volume implants and plasma coatings on their surface is made. Influence of the porous sizes on process of growing new bone in an implant surface it is described. The traditional porous structure of a plasma titanic coating is formed due to decrease in extent of deformation of spraying particles on a substrate and it not optimum for growing of a new bone tissue. Modern dense coatings a hydroxyapatite (HA) - the titan have no necessary porous structure, and transfer of cyclic loading through an external layer is not reliable. In too time comparative researches of 17 surfaces of implants at implantation indicate obvious advantages of plasma HA of coatings is not dependent on degree of their crystallinity. Three-dimensional capillary-porous (TCP) titanium coatings in the form of ridges and cavities with additional HA plasma and microplasma coatings are perspective for medical application due to division of dense and porous volumes of a coating, increase in the area of border with a new bone tissue, higher shear and a possibility of spraying of the HA coating with equilibrium structure at a temperature of a surface of titanium at 550 °C. The analysis of HA coating content phase is made depending on the modes of plasma spraying.

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Aleni, Afshin Hasani, Niklas Kretzschmar, Anton Jansson, Iñigo Flores Ituarte et Luc St-Pierre. « 3D printing of dense and porous TiO2 structures ». Ceramics International 46, n^o 10 (juillet 2020) : 16725–32. http://dx.doi.org/10.1016/j.ceramint.2020.03.248.

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Mohammadi, Mehdi, Patricia Pascaud-Mathieu, Valeria Allizond, Jean-Marc Tulliani, Bartolomeo Coppola, Giuliana Banche, Christophe Chaput, Anna Maria Cuffini, Fabrice Rossignol et Paola Palmero. « Robocasting of Single and Multi-Functional Calcium Phosphate Scaffolds and Its Hybridization with Conventional Techniques : Design, Fabrication and Characterization ». Applied Sciences 10, n^o 23 (4 décembre 2020) : 8677. http://dx.doi.org/10.3390/app10238677.

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In this work, dense, porous, and, for the first time, functionally-graded bi-layer scaffolds with a cylindrical geometry were produced from a commercially available hydroxyapatite powder using the robocasting technique. The bi-layer scaffolds were made of a dense core part attached to a surrounding porous part. Subsequently, these bi-layer robocast scaffolds were joined with an outer shell of an antibacterial porous polymer layer fabricated by solvent casting/salt leaching techniques, leading to hybrid ceramic-polymer scaffolds. The antibacterial functionality was achieved through the addition of silver ions to the polymer layer. All the robocast samples, including the bi-layer ones, were first characterized through scanning electron microscopy observations, mechanical characterization in compression and preliminary bioactivity tests. Then, the hybrid bi-layer ceramic-polymer scaffolds were characterized through antimicrobial tests. After sintering at 1300 °C for 3 h, the compressive strengths of the structures were found to be equal to 29 ± 4 MPa for dense samples and 7 ± 4 MPa for lattice structures with a porosity of 34.1%. Bioactivity tests performed at 37 °C for 4 weeks showed that the precipitated layer on the robocast samples contained octacalcium phosphate. Finally, it was evidenced that the hybrid structure was effective in releasing antibacterial Ag+ ions to the surrounding medium showing its potential efficiency in limiting Staphylococcus aureus proliferation during surgery.

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Sasa, Wang, Liu Hongling, Zhang Liangying et Yao Xi. « Probing the nature and the structure of dense gel in porous silica ». Ferroelectrics 196, n^o 1 (mai 1997) : 97–100. http://dx.doi.org/10.1080/00150199708224141.

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THONGJOON, Watcharaporn, Kamon AIEMPANAKIT, Itsarapong CHUASONTIA et Chantana AIEMPANAKIT. « Morphology and electrochromic property of chemical bath deposited NiO films at different NiSO4 concentration ». Journal of Metals, Materials and Minerals 32, n^o 4 (26 décembre 2022) : 87–92. http://dx.doi.org/10.55713/jmmm.v32i4.1534.

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In this study, nickel oxide (NiO) films were prepared on indium tin oxide (ITO) glass by a chemical bath deposition (CBD) at different nickel sulfate (NiSO4) concentrations. The NiO films were verified for their structural properties with field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) while the optical properties were investigated using a spectrophotometer. Moreover, the NiO films were studied to assess their electrochemical properties by cyclic voltammetry in potassium hydroxide (KOH) electrolyte. The results showed that annealed NiO films exhibited the dominant crystal structure of the (111) plane. Meanwhile, the NiSO4 concentration controlled morphological structure between dense and porous structures. The porous structure of NiO film was produced with the NiSO4 concentration in the range of 0.2 M to 1.0 M and the most porous structure was NiSO4 concentration at 0.8 M with a porosity of 64.56%. The optical contrast was calculated between bleached and colored states which were obtained at a maximum of 51.39% for NiO films at 0.8 NiSO4 concentration. Morphological effects and electrochromic properties were highly consistent. Analysis of the cyclic voltammetry (CV) results revealed that the cyclic stability for the highly porous structure of NiO films was more deteriorating than the less porous films.

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Junoh, Hazlina, Juhana Jaafar, Nik Abdul Hadi Md Nordin, Ahmad Fauzi Ismail, Mohd Hafiz Dzarfan Othman, Mukhlis A. Rahman, Farhana Aziz et Norhaniza Yusof. « Performance of Polymer Electrolyte Membrane for Direct Methanol Fuel Cell Application : Perspective on Morphological Structure ». Membranes 10, n^o 3 (25 février 2020) : 34. http://dx.doi.org/10.3390/membranes10030034.

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Membrane morphology plays a great role in determining the performance of polymer electrolyte membranes (PEMs), especially for direct methanol fuel cell (DMFC) applications. Membrane morphology can be divided into two types, which are dense and porous structures. Membrane fabrication methods have different configurations, including dense, thin and thick, layered, sandwiched and pore-filling membranes. All these types of membranes possess the same densely packed structural morphology, which limits the transportation of protons, even at a low methanol crossover. This paper summarizes our work on the development of PEMs with various structures and architecture that can affect the membrane’s performance, in terms of microstructures and morphologies, for potential applications in DMFCs. An understanding of the transport behavior of protons and methanol within the pores’ limits could give some perspective in the delivery of new porous electrolyte membranes for DMFC applications.

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Lee, Chae-Young, Sujin Lee, Jang-Hoon Ha, Jongman Lee, In-Hyuck Song et Kyoung-Seok Moon. « Effect of the Sintering Temperature on the Compressive Strengths of Reticulated Porous Zirconia ». Applied Sciences 11, n^o 12 (18 juin 2021) : 5672. http://dx.doi.org/10.3390/app11125672.

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Porous ceramics have separation/collection (open pore) and heat-shielding/sound-absorbing (closed pore) characteristics not found in conventional dense ceramics, increasing their industrial importance along with dense ceramics. Reticulated porous ceramics, a type of porous ceramic material, are characterized by a three-dimensional network structure having high porosity and permeability. Although there have been numerous studies of porous zirconia, which is already widely used, there are insufficient reports on reticulated porous zirconia, and it is still challenging to improve the compressive strength of reticulated porous ceramics thus far, especially considering that too few studies have been published on this topic. Therefore, we prepared reticulated porous zirconia specimens using the replica template method. In this study, the compressive strength outcomes of reticulated porous zirconia were analyzed by controlling the PPI value (25, 45, 60, and 80 PPI) of the sacrificial polymer template, the average zirconia particle size (as-received, coarse, intermediate, and fine), and the sintering temperature (1400, 1500, and 1600 °C). Consequently, we confirm that it is possible to prepare reticulated porous zirconia with a wide range of strengths (0.16~1.26 MPa) as needed with an average particle size and while properly controlling the sintering temperature.

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Xu, Nan. « Research and Application of Building Enclosing Structure Used in Equipment Noise Control ». Applied Mechanics and Materials 423-426 (septembre 2013) : 1272–78. http://dx.doi.org/10.4028/www.scientific.net/amm.423-426.1272.

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Porous material has a function of sound absorption, dense hard material can prevent the spread of airborne sound. The building envelope which is made up of different properties of materials, with good effects on sound insulation, sound absorption and noise elimination, can be widely used in noise control engineering.

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Khimich, Margarita A., Konstantin A. Prosolov, Tatiana Mishurova, Sergei Evsevleev, Xavier Monforte, Andreas H. Teuschl, Paul Slezak et al. « Advances in Laser Additive Manufacturing of Ti-Nb Alloys : From Nanostructured Powders to Bulk Objects ». Nanomaterials 11, n^o 5 (29 avril 2021) : 1159. http://dx.doi.org/10.3390/nano11051159.

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The additive manufacturing of low elastic modulus alloys that have a certain level of porosity for biomedical needs is a growing area of research. Here, we show the results of manufacturing of porous and dense samples by a laser powder bed fusion (LPBF) of Ti-Nb alloy, using two distinctive fusion strategies. The nanostructured Ti-Nb alloy powders were produced by mechanical alloying and have a nanostructured state with nanosized grains up to 90 nm. The manufactured porous samples have pronounced open porosity and advanced roughness, contrary to dense samples with a relatively smooth surface profile. The structure of both types of samples after LPBF is formed by uniaxial grains having micro- and nanosized features. The inner structure of the porous samples is comprised of an open interconnected system of pores. The volume fraction of isolated porosity is 2 vol. % and the total porosity is 20 vol. %. Cell viability was assessed in vitro for 3 and 7 days using the MG63 cell line. With longer culture periods, cells showed an increased cell density over the entire surface of a porous Ti-Nb sample. Both types of samples are not cytotoxic and could be used for further in vivo studies.

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Chen, Youlong, Liang Ma et Sijing Ding. « Enhanced Photocatalytic Hydrogen Generation by Optimized Plasmonic Hot Electron Injection in Structure-Adjustable Au-ZnO Hybrids ». Catalysts 10, n^o 4 (1 avril 2020) : 376. http://dx.doi.org/10.3390/catal10040376.

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Plasmonic Au-ZnO hybrids with adjustable structures (including Au-decorated ZnO and core–shell Au@ZnO with dense and porous ZnO shells) and the optimized hot electron-driven photocatalytic activity were successfully prepared. It was found that the Au@ZnO core–shell hybrids with porous morphology had the highest plasmon-enhanced photocatalytic hydrogen generation activity under visible light irradiation. The wavelength-dependent photocatalytic tests verified that Au@ZnO with porous ZnO shells had the highest apparent quantum efficiency upon resonance excitation. The ultrafast transient absorption measurements revealed that Au@ZnO with porous ZnO shells had the fastest plasmon-induced hot electron injection, which was thought to be the reason for the improved photocatalytic activity. This work might provide a promising route to designing photocatalytic and photoelectric materials.

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Xu, Li Bin, Nai Qian Feng et Ch'ng Guan Bee. « Research on Preparation Technique of C100 Ultra-High Performance Self-Compaction Concrete ». Advanced Materials Research 716 (juillet 2013) : 30–35. http://dx.doi.org/10.4028/www.scientific.net/amr.716.30.

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Self-compaction concrete is a new green concrete featuring self-leveling, self-compaction, low noise and low consumption of labor force. Nowadays, a large number of super high-rise buildings (h>400m) are under construction around the world, the complicated structures and dense reinforcement placement has brought numerous inconveniences to construction of concrete. Research on high strength / ultra-high strength self-compaction concrete thus becomes a hotspot. The porous structure of zeolite powder can help absorb the water reducing agent and then release it slowly in concrete mixture. With the low slump loss it produces, the prepared C100UHP-SCC can resist slump loss for over 3 hours. Test of super-high pumping at a height of 411m is carried out in the West Tower program at Pearl River New Town of Guangzhou (the building height is 441m). Drilled core test for L-shaped component indicates a dense internal structure, so it has a desirable self-compaction and capacity to pass through dense reinforcement.

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Salehi, Zahra, Francesco Basoli, Igor Luisetto, S. Licoccia et Elisabetta di Bartolomeo. « Spin-Coated La_0.8Sr_0.2Ga_0.8Mg_0.2O_3-_δ Electrolyte on Infiltrated Anodes for Biogas Utilization ». Advances in Science and Technology 93 (octobre 2014) : 7–12. http://dx.doi.org/10.4028/www.scientific.net/ast.93.7.

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Dense micrometric La0.8Sr0.2Ga0.8Mg0.2O3-δ (LSGM) films were deposited by spin-coating on porous LSGM scaffolds characterized by an homogeneous pore structure. Porous anodes were infiltrated with aqueous nickel nitrate solutions, dried and fired at 700 °C. Homogeneous metal coating with proper interconnections was observed by SEM, chemical stability was confirmed by XRD. Fuel cell tests and electrochemical impedance spectroscopy (EIS) were performed and discussed.

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Podgorbunsky, Anatoly, Dmitry Mashtalyar, Igor Imshineskiy, Sergey Sinebryukhov et Sergey Gnedenkov. « Porous magnesium scaffolds with biodegradable polycaprolactone coating ». MATEC Web of Conferences 329 (2020) : 02024. http://dx.doi.org/10.1051/matecconf/202032902024.

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The results of the synthesis of magnesium matrices with a porous structure have been presented. The cavities sizes vary from 10 microns to hundreds of microns. It has been obtained porous magnesium samples coated by spin-coating with biodegradable polycaprolactone. It has been shown that a dense layer of biodegradable polymer more than 50 μm thickness can be formed on the sample surface. Study of the electrochemical properties of the obtained coatings has been carried out. Obtained results suggest that porous magnesium metals with protective coatings can be used as degradable bone substitute implants.

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Liu, Hui, Jin Cai et Jihong Zhu. « Hot Corrosion Behavior of BaLa2Ti3O10 Thermal Barrier Ceramics in V2O5 and Na2SO4 + V2O5 Molten Salts ». Coatings 9, n^o 6 (29 mai 2019) : 351. http://dx.doi.org/10.3390/coatings9060351.

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BaLa2Ti3O10 ceramics for thermal barrier coating (TBC) applications were fabricated, and exposed to V2O5 and Na2SO4 + V2O5 molten salts at 900 °C to investigate the hot corrosion behavior. After 4 h corrosion tests, the main reaction products resulting from V2O5 salt corrosion were LaVO4, TiO2, and Ba3V4O13, whereas those due to Na2SO4 + V2O5 corrosion consisted of LaVO4, TiO2, BaSO4 and some Ba3V4O13. The structures of reaction layers on the surfaces depended on the corrosion medium. In V2O5 salt, the layer was dense and had a thickness of 8–10 μm. While in Na2SO4 + V2O5 salt, it had a ~15 μm porous structure and a dense, thin band at the bottom. Beneath the dense layer or the band, no obvious molten salt was found. The mechanisms by which the reaction layer forms were discussed.

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Mohd Razali, Razmi Noh, Bulan Abdullah, Muhammad Hussain Ismail et Norhamidi Muhamad. « Characteristic of Modified Geometrical Open-Cell Aluminum Foam by Casting Replication Process ». Materials Science Forum 846 (mars 2016) : 37–41. http://dx.doi.org/10.4028/www.scientific.net/msf.846.37.

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In this work, aluminium foams with modified geometry were successfully fabricated with a combination of dense and porous structure The main objective of this study were to determine the initial physical properties of aluminium foam with modified geometry in terms of density, porosity and morphology. Three different NaCl space holder sizes ranging from 1 mm to 3 mm were sieved and used to replicate the final pore size of aluminium foam. The samples were successfully produced through casting replication process. After densification, samples underwent water leaching in ultrasonic bath to remove completely the space holder. Results showed that porosity of the aluminium foam increased from 50 – 62% when the size of space holder was increased from 1 mm to 3 mm. The morphology showed clearly an integrated modified geometry between dense and inter-connected porous structure which is beneficial for applications that require combination properties of structural, thermal and mechanical properties.

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Chen, Zhe, Kenji Ito, Hiroshi Yanagishita, Nagayasu Oshima, Ryoichi Suzuki et Yoshinori Kobayashi. « Layer Structures of Composite Membranes for Water Filtration Elucidated by Variable-Energy Positron Annihilation ». Materials Science Forum 733 (novembre 2012) : 45–48. http://dx.doi.org/10.4028/www.scientific.net/msf.733.45.

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Commercial composite membranes for water purification were studied by means of the variable-energy positron annihilation γ-ray technique. The positron incident energy E dependence of R parameter (3γ/2γ ratio) analyzed from positron annihilation γ-ray spectra revealed the layer structure consisting of a dense top layer and a porous substrate for the membranes. Thickness of the dense layer for each membrane was evaluated from the R(E) based on a positron implantation stopping profile.

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Molinari, Alberto, Mario Zadra, Nério Vicente Jr., Luca Facchini et Francesco Bucciotti. « Spark Plasma Sintering of Titanium Alloys for Biomedical Applications ». Key Engineering Materials 704 (août 2016) : 360–65. http://dx.doi.org/10.4028/www.scientific.net/kem.704.360.

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A dense Ti6Al4V with a porous cp2-Ti surface layer was produced by Spark Plasma Sintering, using a Calcium Phosphate powder as space holder. The duplex porosity structure resulting from the space holder (large pores) and the uncompleted densification of the titanium powder (micrometric pores) has a very positive effect on both cell in-growth and cell proliferation.The porous structure decreases the fatigue resistance significantly, even if less than what reported in literature, likely due to the formation of a globular microstructure in the interface region of the substrate, where fatigue crack nucleation occurs. The porous surfaced specimens succeeded the adhesion by pull-off test, the resistance to static and cyclic shear stresses and the Taber abrasion test.

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Li, Wei, et Hai Ying Zhang. « Analysis of Microstructure of Interfacial Transition Zone (ITZ) in Recycled Aggregate Concrete ». Advanced Materials Research 811 (septembre 2013) : 249–53. http://dx.doi.org/10.4028/www.scientific.net/amr.811.249.

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Experiments on influence of species of aggregate and mixing method on interfacial zone in recycled aggregate concrete were investigated. SEM observations revealed that a recycle normal-strength concrete aggregate consist of loose and porous interfacial structure, whereas a recycled high performance concrete (HPC) aggregate and a triple mixing (TM) consist mainly of dense hydrates. Various admixtures on ITZ was produced that consumed CH in the pore, modified attached cement mortar. Strength of recycled concrete was explained by interaction between cements paste and recycled aggregate. The result verified that the relatively dense pore structure of the recycled concrete benefit to development of mechanical properties.

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Xu, Gui Ying. « Thermoelectric Properties and Mechanism on Porous Silicon Wafer ». Key Engineering Materials 336-338 (avril 2007) : 900–904. http://dx.doi.org/10.4028/www.scientific.net/kem.336-338.900.

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In order to improve conversion efficiency of thermoelectric materials, a designing model named Combined Model of Dense and Hollow Quantum Structures (CMDHQS) and a concept named Combined Effect of Dense and Hollow Quantum Structures (CEDHQS) have been proposed. A proof-of-concept experiment has been carried out for fabrication of porous silicon wafer with CMDHQS by physical vapor deposition and selective chemical erosion methods. By the investigation on the relation of microstructure, micro-composition and thermoelectric properties, it is found that porous silicon wafers with CMDHQS can be obtained by these two methods and have much higher thermoelectric properties than normal silicon materials, that is 3 times higher than the highest results reported, which make porous silicon become a candidate as thermoelectric materials.

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Liu, Rong Zheng, Ma Lin Liu, Jia Xing Chang, You Lin Shao, Bing Liu et Chang Sheng Deng. « Preparation and Performance of Fully Ceramic Fuel Element Using Silicon Carbide as Coating Layers ». Key Engineering Materials 697 (juillet 2016) : 835–40. http://dx.doi.org/10.4028/www.scientific.net/kem.697.835.

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Tristructural-isotropic (TRISO) coated fuel particles with spherical ceramic fuel kernels followed by three layers of pyrolytic carbon and one layer of silicon carbide (SiC) is successfully used in high temperature gas cooled reactor (HTGR) system. In this paper, an improved design concept of fully ceramic fuel is proposed. The kernels were coated by SiC layers with different densities. Two kinds of SiC coatings, namely porous SiC and dense SiC were prepared by a fluidized bed chemical vapor deposition method. The densities of porous SiC and dense SiC were 1.40 g/cm3 and 3.20 g/cm3, respectively. By controlling experimental parameters, densities of the SiC layer can be adjusted. The structure and micromorphology of the coated particles were investigated by various technologies such as XRD, SEM, and EDX. The coated particles were dispersed in SiC matrix and further sintered to dense compacts. High temperature oxidation test confirmed the robustness of the fuel elements.

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Terriault, Patrick, et Vladimir Brailovski. « Influence of Boundary Conditions on the Simulation of a Diamond-Type Lattice Structure : A Preliminary Study ». Advances in Materials Science and Engineering 2017 (2017) : 1–8. http://dx.doi.org/10.1155/2017/6471209.

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Emergent additive manufacturing processes allow the use of metallic porous structures in various industrial applications. Because these structures comprise a large number of ordered unit cells, their design using conventional modeling approaches, such as finite elements, becomes a real challenge. A homogenization technique, in which the lattice structure is simulated as a fully dense volume having equivalent material properties, can then be employed. To determine these equivalent material properties, numerical simulations can be performed on a single unit cell of the lattice structure. However, a critical aspect to consider is the boundary conditions applied to the external faces of the unit cell. In the literature, different types of boundary conditions are used, but a comparative study is definitely lacking. In this publication, a diamond-type unit cell is studied in compression by applying different boundary conditions. If the porous structure’s boundaries are free to deform, then the periodic boundary condition is found to be the most representative, but constraint equations must be introduced in the model. If, instead, the porous structure is inserted in a rigid enclosure, it is then better to use frictionless boundary conditions. These preliminary results remain to be validated for other types of unit cells loaded beyond the yield limit of the material.

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Ganesh, N., et S. Rambabu. « Finite Element Analysis of Porous Ti-6Al-4V Alloy Structures for Biomedical Applications ». Journal of Physics : Conference Series 2070, n^o 1 (1 novembre 2021) : 012224. http://dx.doi.org/10.1088/1742-6596/2070/1/012224.

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Abstract In this article, design and finite element simulation of porous Ti-6Al-4V alloy structures was presented. Typically, titanium and titanium alloy implants can be manufactured with required pore size and porosity volume by using powder bed fusion techniques due to advancement in additive manufacturing technologies. However, the mismatch of elastic modulus between human cortical bone and the dense Ti-6Al-4V alloy implant resulted in stress shielding which accelerate the implant failure. The porous implant structures help in reduce the mismatch of elastic modulus between the cortical bone and implant structure and also improve the bone ingrowth. Hence, the present work focuses on design of Ti-6Al-4V alloy porous structures with various porosities ranging from 10% to 70% and simulated to determine the elastic modulus suitable for human cortical bone. The sample with 45% porosity is found to be best suited for replacement of cortical bone with elastic modulus of 74Gpa, preventing stress shielding effect and enhanced chances of bone ingrowth.

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Zhou, Junshuang, Li Hou, Jie Lian, Wenbo Cheng, Dong Wang, Huiyang Gou et Faming Gao. « Nitrogen-doped highly dense but porous carbon microspheres with ultrahigh volumetric capacitance and rate capability for supercapacitors ». Journal of Materials Chemistry A 7, n^o 2 (2019) : 476–85. http://dx.doi.org/10.1039/c8ta05984e.

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Sousa, T. H. S., C. A. Fortulan, E. S. Antunes et B. de M. Purquerio. « Concept of a Bioactive Implant with Functional Gradient Structure ». Key Engineering Materials 396-398 (octobre 2008) : 221–24. http://dx.doi.org/10.4028/www.scientific.net/kem.396-398.221.

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A material able to be used as bone implant for specific applications was developed. The proposed solution establishes that all implant surfaces should be bioactive since porous surfaces in contact with bone are extremely necessary for bone adhesion. The bioactive material composite with high mechanical strength designed with a PMMA functional structure gradient produced in this work has a dense core enveloped by a porous bioactive surface. Pore sizes and shapes as well their interconnectivity was analyzed by SEM tests; the cytotoxicity was investigated in vitro using Vero cell and bone conductivity and biocompatibility was investigated in vivo in rabbits. The implant porous bioactive part analyzed in vitro showed no toxicity and tests in vivo showed a remarkable biocompatibility and bone cell growth. Some samples with hydroxyapatite (HAp) were analyzed by EDX and SEM tests, the results showed a fair hydroxyapatite distribution in the implant pore surfaces as much as a part which was retained inside the PMMA inner porous. The average scaffold pore sizes obtained was around 250.0µm and the diameter shrinkage of 4.0% was observed in all samples. This study demonstrated that the functional gradient structure composite studied can be a good candidate for cranial bone implants due to its good bone conductivity and biocompatibility.

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Zhao, Qing Nan, Ying Liu, Shao Hong Hou, Wu Zeng et Jie Sun. « Preparation and Characterization of Nano-Porous SiO₂/TiO₂-SiO₂Thin Films on Glass Substrates by Sol-Gel Method ». Key Engineering Materials 531-532 (décembre 2012) : 651–54. http://dx.doi.org/10.4028/www.scientific.net/kem.531-532.651.

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Nano-porous bilayers structure antireflection films on glass substrate were prepared by sol-gel method, tetraethyl orthosilicate(TEOS) and tetrabutyl titanate(TEOT) as the main raw materials, cetyl trimethyl ammonium bromide(CTAB) and polyethylene glycol(PEG) as template. The relation of the template agent addition, pH, and aging time to surface morphology and optical properties were analyzed. When the CTAB/TEOS = 1/30, the average spectral transmittance in the visible wavelength is 93.69% and the peak transmission is up to 97.37%. All the bilayers antireflection films are amorphous structure, uniform surface morphology, dense nano-porous size distribution, pore size is about 10nm.

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Grigoriev, Fedor Vasilievich, Vladimir Borisovich Sulimov et Alexander Vladimirovich Tikhonravov. « Molecular Dynamics Simulation of Laser Induced Heating of Silicon Dioxide Thin Films ». Nanomaterials 11, n^o 11 (6 novembre 2021) : 2986. http://dx.doi.org/10.3390/nano11112986.

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The full-atomistic classical molecular dynamics simulation of the laser heating of silicon dioxide thin films is performed. Both dense isotropic films and porous anisotropic films are investigated. It is assumed that heating occurs due to nodal structural defects, which are currently considered one of the possible causes of laser induced damage. It is revealed that heating to a temperature of 1000 K insignificantly affects the structure of the films and the concentration of point defects responsible for the radiation absorption. An increase in the heating temperature to 2000 K leads to the growth of the concentration of these defects. For “as deposited” films, this growth is greater in the case of a porous film deposited at a high deposition angle. Annealing of film reduces the difference in the concentration of laser induced defects in dense and porous films. The possible influence of optical active defects arising due to heating on the laser induced damage threshold is discussed.

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Li, Zhangnan, Qinghao Meng, Yajie Yang, Xiaoqin Zou, Ye Yuan et Guangshan Zhu. « Constructing amidoxime-modified porous adsorbents with open architecture for cost-effective and efficient uranium extraction ». Chemical Science 11, n^o 18 (2020) : 4747–52. http://dx.doi.org/10.1039/d0sc00249f.

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