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991.
James L. Smialek Michael D. Cuy Bryan J. Harder Anita Garg Richard B. Rogers 《Journal of the American Ceramic Society》2020,103(12):7014-7030
A thermal barrier coating (TBC) system survived 500 hours in aggressive, 1300°C burner rig testing. The yttria-stabilized zirconia (7YSZ) TBC was plasma sprayed on an oxidation-resistant Ti2AlC-type MAX phase and tested in a jet fuel burner at 100 m/s, using 5 hours cycles. No coating spallation or surface recession was observed; Al2O3-scale growth produced a slight 2.4 mg/cm2 mass gain. The coating surface exhibited craze-cracked colonies of [111]flourite textured columns, with no visible moisture attack. The 20 μm alumina scale remained intact under the YSZ face, about twice that producing failure for TBC/superalloy systems. TiO2 nodules, initially formed on the uncoated backside, were removed, and Al2O3 was etched through volatile hydroxides formed in water vapor (~10%). Overall, the test indicated exceptional stability of the YSZ/Al2O3/Ti2AlC system under turbine conditions due in large part to close thermal expansion matching. 相似文献
992.
993.
Mahsa Barzegar Rabi Behrooz Hamid Reza Mansouri Saeed Kazemi Najafi Linda F. Lorenz Charles R. Frihart 《Journal of the American Oil Chemists' Society》2020,97(12):1371-1383
Canola is widely grown in the northern latitudes for its vegetable oil, generating large quantities of residual, low value canola flour used as animal feed. The common wood adhesive poly(diphenylmethylene diisocyanate) (pMDI) should react with the wide variety of functional groups in proteins. Therefore, it would seem that canola flour with added pMDI could be an effective adhesive. Two main questions are addressed in this study: How do the wood adhesive properties of canola flour compare to the better-studied soy flour? How well do proteins, which contain an abundance of functional groups, cure with the very reactive pMDI? These questions were addressed using the small-scale adhesive strength test ASTM D-7998, with various adhesive formulations and bonding conditions for canola flour plus pMDI compared to soy adhesives. The more challenging wet cohesive bond strength was emphasized because the dry strengths were usually very good. Generally, soy adhesives were better than canola ones, as was the polyamidoamine-epichlorohydrin cross-linker compared to pMDI, but these generalizations can be altered by the conditions selected. Three-ply plywood tests supported the small-scale test results. 相似文献
994.
Channa Wang Ling Li Huihua Wang Tianpeng Qu Jun Tian Deyong Wang Zhenhui Kang 《加拿大化工杂志》2020,98(8):1784-1793
Cost-effective catalysts for hydrogen evolution reaction (HER) are attractive for sustainable production of H2 fuel. Herein, a series of tunable Ni/Fe-Mo carbide catalysts have been synthesized via a sol-gel method coupling with a subsequent high temperature carbonization process. The amount of nickel and iron was tuned in the Mo7/C precursors, accomplishing a favourable performance of noble-metal-free electrocatalysts for HER. As expected, the designed Ni10Fe4Mo7/C catalyst displays an enhanced catalytic activity toward hydrogen production with an ultralow overpotential (η10 = 110 mV) and striking kinetics (ηonset = 58 mV, k = 54 mV · dec−1) in the alkaline electrolyte (1 M KOH), which are comparable to those of the commercial 20% Pt/C catalyst. Such excellent performance of Ni10Fe4Mo7/C could be attributed to the high intrinsic activities of Ni-based alloys (NiMo4) and Mo2C, as well as to the lattice contraction in the Mo2C unit cell, in accordance with its high electrochemical surface area (~133 m2 · g−1) and low charge-transfer resistance (~31.5 Ω) for the associated electrode. 相似文献
995.
The selective oxidation of alkane and olefin moieties are reactions of fundamental importance in both chemical synthesis and biology. Nature efficiently catalyzes the oxidation of hydrocarbons using iron-dependent enzymes, which operate through the mediation of oxoiron(IV) or oxoiron(V) species. In the quest for chemo, regio and stereoselective transformations akin to those taking place in nature, bioinspired iron catalysts have been developed and understanding their mechanism of action has become a particularly relevant area of research. While a prominent advance in the preparation and characterization of oxoiron(IV) species has been accomplished, oxoiron(V) species remain exceedingly rare, presumably because the high reactivity that makes them particularly interesting also makes them difficult to observe. This review summarizes the advances in the field, focusing in synthetic systems for which the oxoiron(V) species relevant in these transformations have been directly detected and spetroscopically characterized. 相似文献
996.
There has been a great interest in research towards elastomers and their composites with an attempt to obtain the desired biological and mechanical response to scaffold materials in bone tissue engineering. Composites made of ceramic-thermoplastic mixtures have been shown success to deliver the inorganic component while fail to provide replacement of an elastic protein, that is, collagen, of the target bone tissue. Thus, in order to match up with the inherent elasticity of the native tissue, it is proposed an alternative to well-known thermoplastic-containing matrices by using a poly(glycerol-sebacate) (PGS)–beta-tricalcium phosphate elastomeric composite to offer flexibility and mechanical integrity. This study reports for the first time a successful extrusion of PGS containing biodegradable composites with shape-memory feature. The resulting structures are physically and chemically characterized. In vitro cell culture performance of the obtained materials is investigated by using an MC3T3-E1 mouse preosteoblast cell line. The materials obtained in this study can be shaped into the desired size and various forms via temperature stimuli. Resulting materials have been proposed for craniofacial tissue engineering as a bone filler in which surgeons need to shape biomaterials during the surgical procedure due to the complex geometry of the bones. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 137, 48689. 相似文献
997.
998.
Ibdal Satar Mimi Hani Abu Bakar Wan Ramli Wan Daud Nazlina Haiza Mohd Yasin Mahendra Rao Somalu Byung Hong Kim 《国际能源研究杂志》2020,44(9):7464-7476
The low cost, low over-potential loss, good catalytic properties for hydrogen evolution reaction (HER), high corrosion stability, commercially available, and could be applied in pH-neutral solution and ambient temperature are important properties for the cathode materials when it is applied in microbial electrolysis cell (MEC) technology. This study has two-pronged objectives: the first is to investigate the feasibility of titanium (Ti) and graphite felt (GF) coated with nickel (Ni), and the second is to generate hydrogen from the fermentation effluent (FE). The electrodeposition (ED) method was used to deposit Ni catalyst onto Ti (Ni/Ti) and GF (Ni/GF) surfaces. The scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy were used to characterize the cathode morphology and element composition. The catalytic properties of Ni/Ti and Ni/GF could be evaluated using the linear sweep voltammetry tests. The maximum volumetric H2 production rates of MEC using Ni/Ti and Ni/GF cathodes were obtained at 0.39 ± 0.01 and 0.33 ± 0.03 m3 H2 m−3 d−1 respectively. The Ni/Ti and Ni/GF cathodes could be used as alternative cathodes while producing hydrogen from FE. 相似文献
999.
1000.
Lin Zhu Jialun Li Yufei Jia Penghui Zhu Maoxiang Jing Shanshan Yao Xiangqian Shen Songjun Li Feiyue Tu 《国际能源研究杂志》2020,44(13):10168-10178
A promising solid polymer blend electrolyte is prepared by blending of poly(ethylene oxide) (PEO) with different content of amorphous poly(propylene carbonate) (PPC), in which the amorphous property of PPC is utilized to enhance the amorphous/free phase of solid polymer electrolyte, so as to achieve the purpose of modifying PEO-based solid polymer electrolyte. It indicates that the blending of PEO with PPC can effectively reduce the crystallization and increase the ion conductivity and electrochemical stability window of solid polymer electrolyte. When the content of PPC reaches 50%, the ionic conductivity reaches the maximum, which is 2.04 × 10−5 S cm−1 and 2.82 × 10−4 S cm−1 at 25°C and 60°C, respectively. The electrochemical stability window increases from 4.25 to 4.9 V and the interfacial stability of lithium metal anode is also greatly improved. The solid-state LiFePO4//Li battery with the PEO/50%PPC blend solid polymer electrolyte has good cycling stability, which the maximum discharge specific capacity is up to 125 mAh g−1 at a charge/discharge current density of 0.5 C at 60°C. 相似文献