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SPECKLE INTERFEROMETRY MADE SIMPLE AND CHEAP 总被引:1,自引:0,他引:1
Gary Cloud 《Experimental Techniques》2003,27(4):27-30
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Jacqueline E. Cloud Dr. Yonglong Wang Tara S. Yoder Lauren W. Taylor Prof. Yongan Yang 《Angewandte Chemie (International ed. in English)》2014,53(52):14527-14532
The synthesis of colloidal nanocrystals (NCs) of lithiated group 14 elements (Z=Si, Ge, and Sn) is reported, which are Li4.4Si, Li3.75Si, Li4.4Ge, and Li4.4Sn. LixZ compounds are highly reactive and cannot be synthesized by existing methods. The success relied on separating the surface protection from the crystal formation and using a unique passivating ligand. Bare LixZ crystals were first produced by milling elemental Li and Z in an argon‐filled jar. Then, under the assistance of additional milling, hexyllithium was added to passivate the freshly generated LixZ NCs. This ball‐milling‐assisted surface protection method may be generalized to similar systems, such as NaxZ and KxZ. Moreover, Li4.4Si and Li4.4Ge NCs were conformally encapsulated in carbon fibers, providing great opportunities for studying the potential of using LixZ to mitigate the volume‐fluctuation‐induced poor cyclability problem confronted by Z anodes in lithium‐ion batteries. 相似文献
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We examine the usefulness of a two-dimensional self-consistent mean-field theory for predicting polymer-induced forces between a finite object and a surface. The predictions are compared with scaling results for the compression of a single, end-grafted chain by a disk and for the compression of a brush with an athermal wall. For the former, the mean-field predictions agree with scaling theory and, in addition, provide the necessary prefactor in the scaling expressions for the Helmholtz potential and force of compression. For the brush, the mean-field results agree with the Alexander-de Gennes scaling result at moderate compressions and also provide an analytical expression for the force without any unknown parameters. We also use the mean-field theory to examine the interaction of a model bacterium with a planar substrate and show that steric interactions due to a single polymer chain alone can dominate van der Waals attraction under typical practical conditions and thus prevent bacterial adhesion to the surface. 相似文献
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Cloud Makasu 《Optimization Letters》2013,7(3):607-612
In this note, a vector-valued LQG homing problem subject to a controlled stock-wealth process is formulated. Under certain conditions, the problem is solved explicitly via an auxiliary scalar LQG homing problem. 相似文献
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Surface and interior straini fields in thick specimens of polycarbonate have been measured by an embedded-multiple-grid moiré
method. Interior gratings are photographed through intervening gratings. Coherent optical processing of grating records creates
moiré fringe pattern. A correction procedure was developed to eliminate moiré errors caused by strain-induced gradients of
refractive index. This procedure utilizes the refraction distribution as obtained from observation of a grating from opposite
sides of a specimen. No measurements other than the normal moiré observations are required in order to find actual strains.
The correction technique should be useful in refining the results obtained when other optical methods are used in three-dimensional
situations. The method is utilized to determine strains on the surfaces and at the mid-and quarter-planes of thick compact
tension specimens. Results obtained, after correction, agree with measurements made with embedded strain gages. Maximum tensile
strain occurs on the midplane. The findings are rationalized by consideration of thickness and proximity to the crack tip. 相似文献
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Noncoherent-light speckle interferometry techniques have been used for terrestrial motion measurements. The long imaging distances typical of these applications limit sensitivity and accuracy because of atmospheric turbidity. Experiments show that the performance of camera systems used to record glacier surface speckle agrees with the predictions of theory developed for astronomical work. Several methods to enhance the technique are suggested. 相似文献