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排序方式: 共有793条查询结果,搜索用时 15 毫秒
781.
782.
Brandon Wagner Pankaj Ghildiyal Prithwish Biswas Mahbub Chowdhury Michael R. Zachariah Lorenzo Mangolini 《Advanced functional materials》2023,33(21):2212805
Magnesium is a promising candidate as a solid fuel for energetic applications, however, the diffusion-controlled oxidation mechanism impedes its reaction with an oxidizer, often resulting in diminished performance. In this study, non-thermal plasma processing is implemented to modify the surface of magnesium nanoparticles with silicon in-flight, in the gas-phase to enhance the rate of interfacial reactions and tune the ignition pathways. Allowing the silicon coating to partially oxidize provides direct contact between the fuel and oxidizer, resulting in a nanostructured thermite system at the single particle level. The proximal distance between oxidizer and fuel directly impacts the ignition temperature and, therefore, the combustion kinetics. An intermetallic reaction occurs within the magnesium/silicon system to supplement the heating of the magnesium fuel to initiate its reaction with the oxidizer, resulting in highly reduced ignition thresholds. The ignition temperature is lowered significantly from ≈740 °C for magnesium particles with a native oxide layer to ≈520 °C for particles coated via the in-flight plasma process. 相似文献
783.
Raghuraj Hoshing Dr. Blaise W. Leeber III Dr. Helene Kuhn Dr. David Caianiello Brandon Dale Michael Saladino Robert Lusi Natalie Palaychuk Sarah Weingarten Prof. Amit Basu 《Chembiochem : a European journal of chemical biology》2022,23(6):e202100532
Yariv reagents are glycosylated triphenylazo dyes that bind to arabinogalactan proteins (AGPs), proteoglycans found in plant cell walls that are integral for plant growth and development. Yariv reagents are widely utilized as imaging, purification, and quantification tools for AGPs and represent the only small molecule probe for interrogating AGP function. The ability of Yariv reagents to bind to AGPs is dependent on the structure of the terminal glycoside on the dye. The reason for this selectivity has not been understood until the present work. Using circular dichroism spectroscopy, we show that the Yariv reagents form supramolecular aggregates with helical chirality. More significantly, the ability of the Yariv reagent to bind AGPs is correlated with this helical chirality. This finding paves the way towards developing a more detailed understanding of the nature of the Yariv-AGP complex, and the design of AGP-binding reagents with higher affinities and selectivities. 相似文献
784.
Harini Gunda Keith G. Ray Leonard E. Klebanoff Chaochao Dun Maxwell A. T. Marple Sichi Li Peter Sharma Raymond W. Friddle Joshua D. Sugar Jonathan L. Snider Robert D. Horton Brendan C. Davis Jeffery M. Chames Yi-Sheng Liu Jinghua Guo Harris E. Mason Jeffrey J. Urban Brandon C. Wood Mark D. Allendorf Kabeer Jasuja Vitalie Stavila 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(6):2205487
Metal boride nanostructures have shown significant promise for hydrogen storage applications. However, the synthesis of nanoscale metal boride particles is challenging because of their high surface energy, strong inter- and intraplanar bonding, and difficult-to-control surface termination. Here, it is demonstrated that mechanochemical exfoliation of magnesium diboride in zirconia produces 3–4 nm ultrathin MgB2 nanosheets (multilayers) in high yield. High-pressure hydrogenation of these multilayers at 70 MPa and 330 °C followed by dehydrogenation at 390 °C reveals a hydrogen capacity of 5.1 wt%, which is ≈50 times larger than the capacity of bulk MgB2 under the same conditions. This enhancement is attributed to the creation of defective sites by ball-milling and incomplete Mg surface coverage in MgB2 multilayers, which disrupts the stable boron–boron ring structure. The density functional theory calculations indicate that the balance of Mg on the MgB2 nanosheet surface changes as the material hydrogenates, as it is energetically favorable to trade a small number of Mg vacancies in Mg(BH4)2 for greater Mg coverage on the MgB2 surface. The exfoliation and creation of ultrathin layers is a promising new direction for 2D metal boride/borohydride research with the potential to achieve high-capacity reversible hydrogen storage at more moderate pressures and temperatures. 相似文献
785.
786.
Walter Sebastian Scheld Kwangnam Kim Christian Schwab Alexandra C. Moy Shi-Kai Jiang Markus Mann Christian Dellen Yoo Jung Sohn Sandra Lobe Martin Ihrig Michael Gregory Danner Chia-Yu Chang Sven Uhlenbruck Eric D. Wachsman Bing Joe Hwang Jeff Sakamoto Liwen F. Wan Brandon C. Wood Martin Finsterbusch Dina Fattakhova-Rohlfing 《Advanced functional materials》2023,33(43):2302939
Solid-state batteries (SSBs) with a Li7La3Zr2O12 (LLZO) garnet electrolyte are attracting much attention as robust and safe alternative to conventional lithium-ion batteries. Technical challenges in the practical implementation of garnet SSBs are related to the need for high-temperature sintering, which often leads to undesirable chemical reactions with the cathode material. While these reactions are well understood for composite cathodes, very little is known about similar processes between cathode and separator during battery fabrication. This work focuses on understanding the processes between the composite LiCoO2-LLZO cathode and the LLZO separator and how they affect the battery performance. The extensive diffusion of Co-ions within LLZO, which leads to the often-observed LLZO darkening, is shown to have a significant impact on ionic conductivity, electronic conductivity, and dendrite stability of the separator. Experimental data coupled with large-scale molecular dynamics simulations uncover the diffusion mechanism for Co-ions and identify secondary phases that form during these interactions. In addition to extensive Co-ion diffusion within the grains, a non-uniform segregation of Co-ions at grain boundaries is found leading to the formation of three distinct Co-containing phases. This work offers a general approach to studying the fundamental ion diffusion processes that occur during the fabrication of oxide SSBs. 相似文献
787.
Geng Li Caroline M. Elliott Bruce C. Call Brandon J. Sansom Robert B. Jacobson Binbin Wang 《河流研究与利用》2023,39(9):1857-1874
River turbulence is spatially variable due to interactions between morphology of rivers and physical mechanics of flowing water. Understanding the variation of turbulence in rivers is important for characterizing transport processes of soluble and particulate materials in these systems. We present an exploratory effort to understand ecologically relevant flow patterns using measurements of mean flow and turbulence in a highly engineered river channel around an island in the lower Missouri River. Specifically, the profiles of mean river velocities were investigated to examine the logarithmic relation and associated parameters, including shear velocity and bed roughness. Turbulence intensity and Reynolds shear stress were compared with classic open-channel profiles and previously reported river data in the hydraulics literature. With the capability of pulse-to-pulse coherent Doppler velocity profiling in high spatial resolution, we estimated the profiles of turbulence dissipation rate using resolved one-dimensional velocity spectra. These measurement data allow us to examine the validity of turbulence production-dissipation balance and the classic open-channel profiles of turbulence statistics, including turbulence intensity, Reynolds shear stress, dissipation rate, and eddy viscosity. The field data show a strong variation of turbulence profiles in close vicinity of the river island. In shallow water depths close to the island, turbulence is substantially enhanced in comparison with classic open-channel profiles. Such turbulence enhancement is likely attributed to non-uniformity of the flow structures. 相似文献
788.
Simon Vecchioni Brandon Lu Jordan Janowski Karol Woloszyn Nataša Jonoska Nadrian C. Seeman Chengde Mao Yoel P. Ohayon Ruojie Sha 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(12):2206511
The successful self-assembly of tensegrity triangle DNA crystals heralded the ability to programmably construct macroscopic crystalline nanomaterials from rationally-designed, nanoscale components. This 3D DNA tile owes its “tensegrity” nature to its three rotationally stacked double helices locked together by the tensile winding of a center strand segmented into 7 base pair (bp) inter-junction regions, corresponding to two-thirds of a helical turn of DNA. All reported tensegrity triangles to date have employed turn inter-junction segments, yielding right-handed, antiparallel, “J1” junctions. Here a minimal DNA triangle motif consisting of 3-bp inter-junction segments, or one-third of a helical turn is reported. It is found that the minimal motif exhibits a reversed morphology with a left-handed tertiary structure mediated by a locally-parallel Holliday junction—the “L1” junction. This parallel junction yields a predicted helical groove matching pattern that breaks the pseudosymmetry between tile faces, and the junction morphology further suggests a folding mechanism. A Rule of Thirds by which supramolecular chirality can be programmed through inter-junction DNA segment length is identified. These results underscore the role that global topological forces play in determining local DNA architecture and ultimately point to an under-explored class of self-assembling, chiral nanomaterials for topological processes in biological systems. 相似文献
789.
Dr. Mohamed Ettaoussi Amélie Laversin Brandon Vreulz Dr. Marouane Rami Dr. Nicolas Lebegue Dr. Philippe Delagrange Dr. Daniel Henri Caignard Prof. Patricia Melnyk Dr. Maxime Liberelle Dr. Saïd Yous 《ChemMedChem》2022,17(3):e202100658
In our constant search for new successors of agomelatine, we report herein a new series of compounds resulting from bioisosteric modulation of the naphthalene ring. The isoquinoline and tetrahydroisoquinoline derivatives were synthesized and pharmacologically evaluated. This isosteric replacement of the naphthalene group of agomelatine has led to potent agonist and partial agonist compounds with nanomolar melatonergic binding affinities. Overall, the presence of a nitrogen atom was accompanied with a decrease in the binding affinity toward both MT1 and MT2 and the loss of 5HT2C response, especially for tetrahydroisoquinoline in comparison with the parent compound. Interestingly, due to the presence of this nitrogen atom, a notable improvement in the pharmacokinetic properties was observed for all compounds. 相似文献
790.