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排序方式: 共有2219条查询结果,搜索用时 15 毫秒
91.
Kassoum Barry Gisèle Laure Lecomte-Nana Mohamed Seynou Michael Faucher Philippe Blanchart Claire Peyratout 《International Journal of Applied Ceramic Technology》2022,19(6):3084-3098
Silicate ceramics were shaped using tape casting (TC) and freeze tape casting (FTC) processes from three clays labeled HCR, KORS, and KCR. These clays exhibited mass content of 77% halloysite–10 Å, 29% kaolinite, and 98% kaolinite minerals, respectively. After casting the slurries, the dried tapes were sintered at 1200°C. The microstructure changes were characterized before and after sintering using scanning electron microscopy. The apparent porosity of TC samples was lower (36–47 vol.%) compared to values obtained with FTC samples (67–79 vol.%). The latter samples exhibited a highly textured porosity, with micron-sized pores aligned perpendicular to the tape surfaces. Upon sintering, the porosity of TC samples tended to decrease conversely to the case of FTC samples. Such behavior seemed related to the simultaneous effect of organic additives and ice templating. Consequently, the FTC samples showed a relatively low mechanical strength of 3–7 MPa and thermal conductivity of .14– .22 W m−1 K−1. After sintering, the mullite crystallization contributed to strengthen the bulk materials, helping to compensate for the detrimental effect of porosity on the stress to rupture and on thermal conductivity values. 相似文献
92.
Dr. Lennart Brewitz Dr. Jos J. A. G. Kamps Dr. Petra Lukacik Claire Strain-Damerell Yilin Zhao Dr. Anthony Tumber Tika R. Malla Dr. Allen M. Orville Dr. Martin A. Walsh Prof. Dr. Christopher J. Schofield 《ChemMedChem》2022,17(9):e202200016
The two SARS-CoV-2 proteases, i. e. the main protease (Mpro) and the papain-like protease (PLpro), which hydrolyze the viral polypeptide chain giving functional non-structural proteins, are essential for viral replication and are medicinal chemistry targets. We report a high-throughput mass spectrometry (MS)-based assay which directly monitors PLpro catalysis in vitro. The assay was applied to investigate the effect of reported small-molecule PLpro inhibitors and selected Mpro inhibitors on PLpro catalysis. The results reveal that some, but not all, PLpro inhibitor potencies differ substantially from those obtained using fluorescence-based assays. Some substrate-competing Mpro inhibitors, notably PF-07321332 (nirmatrelvir) which is in clinical development, do not inhibit PLpro. Less selective Mpro inhibitors, e. g. auranofin, inhibit PLpro, highlighting the potential for dual PLpro/Mpro inhibition. MS-based PLpro assays, which are orthogonal to widely employed fluorescence-based assays, are of utility in validating inhibitor potencies, especially for inhibitors operating by non-covalent mechanisms. 相似文献
93.
Claire A. Utton Martin Hayes Joanne Hill Neil B. Milestone John H. Sharp 《Journal of the American Ceramic Society》2008,91(3):948-954
Isothermal conduction calorimetry has been used to monitor the early hydration of Portland–blastfurnace slag (BFS)-blended cements. Portland:BFS composite cements with ordinary Portland cement replacements from 0 to 90 wt% were studied at curing temperatures from 12° to 90°C. Peak II, principally associated with alite (Ca3 SiO5 ) hydration, was accelerated with increasing temperature for all blends. Peak S, associated with BFS hydration, was particularly noticeable at 40° and 60°C. At higher curing temperatures, peak S merged with peak II, indicating thermal activation of BFS. Novel plots of total heat output against percentage replacement show that BFS contributes to the heat of hydration, even at temperatures below its thermal activation. 相似文献
94.
Catalytic steam gasification of Miscanthus X giganteus in fluidised bed reactor on olivine based catalysts 总被引:1,自引:0,他引:1
Rudy MichelSergio Rapagnà Manuela Di Marcello Philippe BurgMuriel Matt Claire CoursonRené Gruber 《Fuel Processing Technology》2011,92(6):1169-1177
The Miscanthus X giganteus (MXG) presents many advantages (high yield, perennial crop, easy harvesting…) so it can be considered as a good candidate in terms of renewable energy sources. Several works have been carried out and were devoted to the MXG, especially in the agricultural field, but this study is the first which deals with gasification in order to produce syngas. The catalytic steam gasification of MXG in a fluidised bed reactor into presence of olivine based catalysts was investigated. Three parameters were studied, the temperature (800 °C and 900 °C), the pellets size (6 mm and 8 mm) and the nature of catalyst (olivine and Ni/olivine). Noteworthy is the efficiency shown by the Ni/olivine at 800 °C, which leads to the production of 1.7 m3 kg− 1 daf of gas, containing 50% of H2. Ni/olivine catalyst was characterised by XRD, TPR and SEM-EDX in order to monitor its structural changes during the process. Moreover, a solvent system of tar recovery was tested, which allows to obtain a more representative set of the whole tars. Then, the tars composition was determined by GC/MS. The identification of different compounds shows the presence of different PAHs, in majority naphthalene. 相似文献
95.
96.
Pierre H. Ravelonandro Dominique H. Ratianarivo Claire Joannis-Cassan Arsène Isambert Marson Raherimandimby 《Food and Bioproducts Processing》2011,89(3):209-216
Arthrospira (Spirulina) platensis Toliara isolated from alkaline and salt lakes in the south-western area of Madagascar is a potential source of proteins that could efficiently fight against food deficiency in developing countries like Madagascar. Up to now, productivity in this country has been low, so a better understanding of the growth conditions of this species is needed to improve its production. Growth experiments were undertaken in bubble columns at laboratory scale. The influence of agitation of the culture, medium salinity (ranging from 13 to 35 g L−1) and CO2 addition (ranging from 0 to 2%, v/v) on growth and protein content was examined. Because Arthrospira cells are fragile, a bubble column without additional mixing gave the best growth. Arthrospira (Spirulina) platensis showed higher specific growth rate (μmax) and protein content for lower salinity. Addition of 1% of CO2 improved the productivity by near 60%. The feasability of semi-continuous culture was demonstrated and optimal culture conditions led to a mean productivity of 0.22 ± 0.03 g L−1 d−1, a mean specific growth rate of 0.015 ± 0.002 h−1 and a protein content of 53 ± 2% of total dry weight. 相似文献
97.
Roland Oltra Alexandre Zimmer Claire Sorriano Fabien Rechou Céline Borkowski Olivier Néel 《Electrochimica acta》2011,(20):7038
Some constituent intermetallic (IMPs) particles at the surface of aluminium alloys are considered as preferential sites for the initiation of structural corrosion resulting in localized trenching around the particles and the surrounding Al matrix. In this work, a modified scanning electrochemical microscope (SECM) experiment was used to induce such phenomena via a local alcalinisation on 200 nm thick aluminium coatings promoting their local dissolution in an aerated 0.1 M NaCl electrolyte. The local alcalinisation was induced by the oxygen reduction reaction on the tip of a SECM which mimics the surface of an isolated IMP. From a phenomenological point of view, reproducible cylindrical damage develops in front of the platinum ultramicroelectrode (UME). Using a 2D finite element modelling to simulate the SECM experiments, the role of the local alcalinisation was validated and the calculated Al dissolution rate was found in agreement with the experimental evaluation. 相似文献
98.
Hassane Oudadesse Eric Wers Xuang Vuong Bui Claire Roiland Bruno Bureau Imane Akhiyat Amany Mostafa Hassan Chaair Hicham Benhayoune Joel Fauré Pascal Pellen-Mussi 《Korean Journal of Chemical Engineering》2013,30(9):1775-1783
Bioactive glass 46S6 and biodegradable therapeutic polymer (Chitosan: CH) have been elaborated to form 46S6-CH composite by freeze-drying process. The kinetics of chemical reactivity and bioactivity at the surface were investigated by using physicochemical techniques, particularly solid-state MAS-NMR. Immortalized cell line used to construct multicellular spheroids was employed as three-dimensional (3D) cell cultures for in vitro studies. Obtained results showed a novel structure of the composite; the chemical treatment (ultrasound, magnetic stirring, freeze drying process and lyophilization) led the bioactive glass particles to be loaded in the chitosan-based materials. 29Si and 31P MAS-NMR results showed the emergence of two new species, Q Si 3 (OH) and Q Si 4 , which are characteristic of the vitreous network dissolution in simulated body fluid (SBF). MAS-NMR also confirmed the formation of amorphous calcium phosphate (ACP) at the surface of the initial 46S6-CH. Three-dimensional (3D) cell cultures highlighted the effect of chitosan, where the cell viability reached up to 78% in 46S6-CH composite and up to 67% in 46S6. The association of (CH) and bioactive glass (BG) matrix promotes a highly significant bioactivity, demonstrating surface bone formation and satisfactory behavior in biological environment. 相似文献
99.
Anja Schrder Joris Sprakel Karin Schroën Claire C. Berton‐Carabin 《European Journal of Lipid Science and Technology》2020,122(6)
Colloidal lipid particles (CLPs) are promising encapsulation systems for lipophilic bioactives, such as oil‐soluble antioxidants that are applied in food and pharmaceutical formulations. Currently, there is no clear consensus regarding the relation between particle structure and the chemical stability of such bioactives. Using α‐tocopherol as a model antioxidant, it is shown that emulsifier type (Tween 20 or 40, or sodium caseinate) and lipid composition (tripalmitin, tricaprylin, or combinations thereof) modulated particle morphology and antioxidant stability. The emulsifier affects particle shape, with the polysorbates facilitating tripalmitin crystallization into highly ordered lath‐like particles, and sodium caseinate resulting in less ordered spherical particles. The fastest degradation of α‐tocopherol is observed in tripalmitin‐based CLPs, which may be attributed to its expulsion to the particle surface induced by lipid crystallization. This effect is stronger in CLPs stabilized by Tween 40, which may act as a template for crystallization. This work not only shows how the architecture of CLPs can be controlled through the type of lipid and emulsifier used, but also gives evidence that lipid crystallization does not necessarily protect entrapped lipophilic bioactives, which is an important clue for encapsulation system design. Practical Applications: Interest in enriching food and pharmaceutical products with lipophilic bioactives such as antioxidants through encapsulation in lipid particles is growing rapidly. This research suggests that for efficient encapsulation, the particle architecture plays an important role; to tailor this, the contribution of both the lipid carrier and the emulsifier needs to be considered. 相似文献
100.
Rosellyne Serewane Deramne Gisèle Laure Lecomte-Nana Claire Peyratout Benoit Naït-Ali Gado Tchangbedji 《International Journal of Applied Ceramic Technology》2020,17(6):2638-2648
The present study aimed at using plant waste (Musa Paradisiaca) for manufacturing clay-based ceramics in order to promote lower sintering temperature while preserving the properties of use. Two kaolinic-illitic clays (NZ1 and KO) from Central African Republic were used mixed with 1 to 10 mass% of the plant waste (MP). The clays and the waste exhibited accessory phases: quartz and iron oxides, and K2O respectively. MP was collected, dried and sieved (<100 μm) previously to its mixture with clays. According to the sintering behavior of KO and NZ1 derived from thermodilatometry, the densification was obtained after firing at 1200°C. Results showed that open porosity decreased from 35% to 17% with increasing temperature in the range 900 to 1200°C for KO and NZ1. This porosity remained in the range 30%-40% while increasing the MP content (firing at 1000°C for 1h.). The optimized MP content was 3 and 5 mass% for KO and NZ1 clay materials respectively. The compressive strength and thermal conductivities were improved compared to clay samples without MP fired at 1200°C. Moreover a significant decrease in the sintering temperature was achieved, leading to energy saving in line with sustainability issues. 相似文献