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排序方式: 共有512条查询结果,搜索用时 31 毫秒
81.
82.
Ghobadi Nader Hafezi Fatemeh Naderi Sirvan Amiri Fatemeh Luna Carlos Arman Ali Shakoury Reza Ţălu Ştefan Rezaee Sahar Habibi Maryam Mardani Mohsen 《Semiconductors》2019,53(13):1751-1758
Semiconductors - The purpose of this research is to explore the properties of CoSe nanostructured thin films on glass substrates prepared by a chemical solution deposition method. Special attention... 相似文献
83.
Sisi He Yueyu Zhang Longbin Qiu Longsheng Zhang Yun Xie Jian Pan Peining Chen Bingjie Wang Xiaojie Xu Yajie Hu Cao Thang Dinh Phil De Luna Mohammad Norouzi Banis Zhiqiang Wang Tsun‐Kong Sham Xingao Gong Bo Zhang Huisheng Peng Edward H. Sargent 《Advanced materials (Deerfield Beach, Fla.)》2018,30(18)
The ability to release, as electrical energy, potential energy stored at the water:carbon interface is attractive, since water is abundant and available. However, many previous reports of such energy converters rely on either flowing water or specially designed ionic aqueous solutions. These requirements restrict practical application, particularly in environments with quiescent water. Here, a carbon‐based chemical‐to‐electricity device that transfers the chemical energy to electrical form when coming into contact with quiescent deionized water is reported. The device is built using carbon nanotube yarns, oxygen content of which is modulated using oxygen plasma‐treatment. When immersed in water, the device discharges electricity with a power density that exceeds 700 mW m?2, one order of magnitude higher than the best previously published result. X‐ray absorption and density functional theory studies support a mechanism of operation that relies on the polarization of sp2 hybridized carbon atoms. The devices are incorporated into a flexible fabric for powering personal electronic devices. 相似文献
84.
F. Pelayo García de Arquer Oleksandr S. Bushuyev Phil De Luna Cao‐Thang Dinh Ali Seifitokaldani Makhsud I. Saidaminov Chih‐Shan Tan Li Na Quan Andrew Proppe Md. Golam Kibria Shana O. Kelley David Sinton Edward H. Sargent 《Advanced materials (Deerfield Beach, Fla.)》2018,30(38)
Electrochemical reduction of CO2 is a compelling route to store renewable electricity in the form of carbon‐based fuels. Efficient electrochemical reduction of CO2 requires catalysts that combine high activity, high selectivity, and low overpotential. Extensive surface reconstruction of metal catalysts under high productivity operating conditions (high current densities, reducing potentials, and variable pH) renders the realization of tailored catalysts that maximize the exposure of the most favorable facets, the number of active sites, and the oxidation state all the more challenging. Earth‐abundant transition metals such as tin, bismuth, and lead have been proven stable and product‐specific, but exhibit limited partial current densities. Here, a strategy that employs bismuth oxyhalides as a template from which 2D bismuth‐based catalysts are derived is reported. The BiOBr‐templated catalyst exhibits a preferential exposure of highly active Bi () facets. Thereby, the CO2 reduction reaction selectivity is increased to over 90% Faradaic efficiency and simultaneously stable current densities of up to 200 mA cm?2 are achieved—more than a twofold increase in the production of the energy‐storage liquid formic acid compared to previous best Bi catalysts. 相似文献
85.
A. Stassi C. D’urso V. Baglio A. Di Blasi V. Antonucci A.S. Arico A.M. Castro Luna A. Bonesi W.E. Triaca 《Journal of Applied Electrochemistry》2006,36(10):1143-1149
A 60 wt% Pt–Fe/C and a 60 wt% Pt–Cu/C catalysts with Fe and Cu content of 5 wt% were prepared by using a combination of colloidal and incipient wetness methods; this has allowed synthesis of small nanostructured crystalline bimetallic catalysts with particle size less than 3 nm and with a suitable degree of alloying. These materials were studied in terms of structure, morphology and composition using XRD, XRF and TEM techniques. The electrocatalytic behaviour for ORR of the catalysts was investigated using the rotating disk technique and compared to that of a pure Pt catalyst with similar particle size. No improvement in performance was recorded with the Pt–Cu compared to Pt catalyst, whereas, a promoting effect in enhancing the ORR was observed for the Pt–Fe catalyst both with and without methanol in the oxygen-saturated electrolyte solution. 相似文献
86.
Stabilization of the Reductase Domain in the Catalytically Self‐Sufficient Cytochrome P450BM3 by Consensus‐Guided Mutagenesis 下载免费PDF全文
Prof. Dr. Gloria Saab‐Rincón Hanan Alwaseem Dr. Valeria Guzmán‐Luna Leticia Olvera Prof. Dr. Rudi Fasan 《Chembiochem : a European journal of chemical biology》2018,19(6):622-632
The multidomain, catalytically self‐sufficient cytochrome P450 BM‐3 from Bacillus megaterium (P450BM3) constitutes a versatile enzyme for the oxyfunctionalization of organic molecules and natural products. However, the limited stability of the diflavin reductase domain limits the utility of this enzyme for synthetic applications. In this work, a consensus‐guided mutagenesis approach was applied to enhance the thermal stability of the reductase domain of P450BM3. Upon phylogenetic analysis of a set of distantly related P450s (>38 % identity), a total of 14 amino acid substitutions were identified and evaluated in terms of their stabilizing effects relative to the wild‐type reductase domain. Recombination of the six most stabilizing mutations generated two thermostable variants featuring up to tenfold longer half‐lives at 50 °C and increased catalytic performance at elevated temperatures. Further characterization of the engineered P450BM3 variants indicated that the introduced mutations increased the thermal stability of the FAD‐binding domain and that the optimal temperature (Topt) of the enzyme had shifted from 25 to 40 °C. This work demonstrates the effectiveness of consensus mutagenesis for enhancing the stability of the reductase component of a multidomain P450. The stabilized P450BM3 variants developed here could potentially provide more robust scaffolds for the engineering of oxidation biocatalysts. 相似文献
87.
Synthesis and Evaluation of the Anticancer and Trypanocidal Activities of Boronic Tyrphostins 下载免费PDF全文
Noemi de J. Hiller Nayane A. A. e Silva Dr. Robson X. Faria Dr. André Luís A. Souza Dr. Jackson A. L. C. Resende André Borges Farias Dr. Nelilma Correia Romeiro Dr. Daniela de Luna Martins 《ChemMedChem》2018,13(14):1395-1404
Molecules containing an (cyanovinyl)arene moiety are known as tyrphostins because of their ability to inhibit proteins from the tyrosine kinase family, an interesting target for the development of anticancer and trypanocidal drugs. In the present work, (E)‐(cyanovinyl)benzeneboronic acids were synthesized by Knoevenagel condensations without the use of any catalysts in water through a simple protocol that completely avoided the use of organic solvents in the synthesis and workup process. The in vitro anticancer and trypanocidal activities of the synthesized boronic acids were also evaluated, and it was discovered that the introduction of the boronic acid functionality improved the activity of the boronic tyrphostins. In silico target fishing with the use of a chemogenomic approach suggested that tyrosine‐phosphorylation‐regulated kinase 1a (DYRK1A) was a potential target for some of the designed compounds. 相似文献
88.
Maghsoudy Soroush Doulati Ardejani Faramarz Molson John Amini Mehdi Ebrahimi Luna 《Mine Water and the Environment》2019,38(1):197-212
Mine Water and the Environment - A shortcoming of the heap leaching process is its inherent limited metal recovery rate, due primarily to preferential pathways, which reduces the efficiency of the... 相似文献
89.
We use a combination of non-contact scanning force microscope operation modes to study the changes in topographic and electrostatic properties of self-assembled monolayer islands of alkylsilanes on mica. The combined technique uses simultaneous electrical and mechanical modulation and feedback modes to produce four images that reveal the topography, phase, surface potential and dielectric constant. The results show significant advantages with this combined method. As an example we show that the interaction of water with self-assembled monolayer islands of alkylsilanes produces changes in the surface potential of the system but not in the topography. 相似文献
90.
Uniform magnetic nanoneedles have been prepared by hydrogen reduction of elongated nanoarchitectures. These precursors are as-prepared or cobalt-coated aggregates of highly oriented haematite nanocrystals (~5?nm). The final materials are flattened nanoneedles formed by chains of assembled Fe or FeCo single-domain nanocrystals. The microstructural properties of such nanoneedles were tailored using renewed and improved synthetic strategies. In this fashion, the needle elongation and composition, the crystallite size (from 15 up to 30?nm), the nanocrystal orientation (with the ?110? or ?001? directions roughly along the long axis of the nanoneedle) and their type of arrangement (single chains, frustrated double chains and double chains) were controlled by modifying the reduction time, the axial ratio of the precursor haematite and the presence of additional coatings of aluminum or yttrium compounds. The values of the coercivity H(C) found for these nanoneedles are compared with the values predicted by the chain of spheres model assuming a symmetric fanning mechanism for magnetization reversal. 相似文献