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排序方式: 共有910条查询结果,搜索用时 15 毫秒
1.
Ramona Luna Daniel Heineck Juan Pablo Hinestrosa Irina Dobrovolskaia Sean Hamilton Anna Malakian Kyle T. Gustafson Katherine T. Huynh Sejung Kim Jason Ware Ella Stimson Christian Ross Carolyn E. Schutt Stuart D. Ibsen 《Electrophoresis》2023,44(15-16):NA-NA
Dielectrophoresis (DEP) is a successful method to recover nanoparticles from different types of fluid. The DEP force acting on these particles is created by an electrode microarray that produces a nonuniform electric field. To apply DEP to a highly conducting biological fluid, a protective hydrogel coating over the metal electrodes is required to create a barrier between the electrode and the fluid. This protects the electrodes, reduces the electrolysis of water, and allows the electric field to penetrate into the fluid sample. We observed that the protective hydrogel layer can separate from the electrode and form a closed domed structure and that collection of 100 nm polystyrene beads increased when this occurred. To better understand this collection increase, we used COMSOL Multiphysics software to model the electric field in the presence of the dome filled with different materials ranging from low-conducting gas to high conducting phosphate-buffered saline fluids. The results suggest that as the electrical conductivity of the material inside the dome is reduced, the whole dome acts as an insulator which increases electric field intensity at the electrode edge. This increased intensity widens the high-intensity electric field factor zone resulting in increased collection. This informs how dome formation results in increased particle collection and provides insight into how the electric field can be intensified to the increase collection of particles. These results have important applications for increasing the recovery of biologically-derived nanoparticles from undiluted physiological fluids that have high conductance, including the collection of cancer-derived extracellular vesicles from plasma for liquid biopsy applications. 相似文献
2.
Cover Picture: A Modular Synthesis of Conformationally Preorganised Extended β‐Strand Peptidomimetics (Chem. Eur. J. 42/2015) 下载免费PDF全文
3.
Iridium‐Catalyzed Enantioselective Allylic Alkylation with Functionalized Organozinc Bromides 下载免费PDF全文
James Y. Hamilton Dr. David Sarlah Prof. Dr. Erick M. Carreira 《Angewandte Chemie (International ed. in English)》2015,54(26):7644-7647
Iridium‐catalyzed enantioselective allylic alkylation of branched racemic carbonates with functionalized alkylzinc bromide reagents is described. Enabled by a chiral Ir/(P,olefin) complex, the method described allows allylic substitution with various primary and secondary alkyl nucleophiles with excellent regio‐ and enantioselectivities. The developed reaction was showcased in a concise, asymmetric synthesis of (?)‐preclamol. 相似文献
4.
Previous experimental and finite element studies have shown the influence of both soil initial conditions and blade operating conditions on cutting forces. However, most of these finite element analyses (FEA) are limited to small blade displacements to reduce element distortion which can cause solution convergence problems. In this study a dynamic three-dimensional FEA of soil–tool interaction was carried out based on predefined failure surfaces to investigate the effect of cutting speed and angle on cutting forces over large blade displacements. Sandy soil was considered in this study and modeled using the hypoplastic constitutive model implemented in the commercial FEA package, ABAQUS. Results reveal the validity of the concept of predefined failure surfaces in simulating soil–tool interaction and the significant effect of cutting acceleration on cutting forces. 相似文献
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J.F. Hamilton 《物理学进展》2013,62(4):359-441
The light-sensitive elements of conventional photographic materials are crystallites principally of the bromide or chloride salts of silver. Certain chemical modifications employing sulphur and gold compounds are used to maximize the response, and organic dyes are adsorbed to provide sensitivity throughout the visible spectrum. Absorption of a few photons results in the reductive formation of one or more clusters of silver or gold atoms on the surface. These clusters act as catalysts to promote further reduction of the host crystallites during photographic development. The success of the system depends upon the particular physical properties of the silver halides, such as their bonding and electron structure, the dielectric properties, the point defect structure, and the electronic transport characteristics. These are all reviewed, and the ways in which they interact to lead to the favourable photodecomposition are followed in some detail. A nucleation-and-growth mechanism operates to provide several of the favourable features of the process, and the chemical treatments used optimize the competition between these desirable steps and the unwanted recombination of electronic carriers. 相似文献
9.
J. H. Northern A. W. J. Thompson M. L. Hamilton P. Ewart 《Applied physics. B, Lasers and optics》2013,111(4):627-635
The detection of multiple species using a single laser and single detector employing multi-mode absorption spectroscopy (MUMAS) is reported. An in-house constructed, diode-pumped, Er:Yb:glass micro-laser operating at 1,565 nm with 10 modes separated by 18 GHz was used to record MUMAS signals in a gas mixture containing C2H2, N2O and CO. The components of the mixture were detected simultaneously by identifying multiple transitions in each of the species. By using temperature- and pressure-dependent modelled spectral fits to the data, partial pressures of each species in the mixture were determined with an uncertainty of ±2 %. 相似文献