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排序方式: 共有885条查询结果,搜索用时 11 毫秒
131.
132.
Zhaowen Lin Larissa S. Novelino Heming Wei Nicolas A. Alderete Glaucio H. Paulino Horacio D. Espinosa Sridhar Krishnaswamy 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(35)
Mechanical metamaterials inspired by the Japanese art of paper folding have gained considerable attention because of their potential to yield deployable and highly tunable assemblies. The inherent foldability of origami structures enlarges the material design space with remarkable properties such as auxeticity and high deformation recoverability and deployability, the latter being key in applications where spatial constraints are pivotal. This work integrates the results of the design, 3D direct laser writing fabrication, and in situ scanning electron microscopic mechanical characterization of microscale origami metamaterials, based on the multimodal assembly of Miura‐Ori tubes. The origami‐architected metamaterials, achieved by means of microfabrication, display remarkable mechanical properties: stiffness and Poisson’s ratio tunable anisotropy, large degree of shape recoverability, multistability, and even reversible auxeticity whereby the metamaterial switches Poisson’s ratio sign during deformation. The findings here reported underscore the scalable and multifunctional nature of origami designs, and pave the way toward harnessing the power of origami engineering at small scales. 相似文献
133.
Summary Dense polymer membranes were made by mixing aqueous solutions of hydrophilic polymers poly(vinyl alcohol) (PVA) and polyethyleneimine
(PEI) in different ratios for investigating the separation of Tetrahydrofuran (THF)/water azeotropic mixtures by pervaporation
(PV). In order to gain a more detailed picture of the molecular transport phenomenon, we have performed sorption gravimetric
experiments at 30 °C to compute diffusion, swelling, sorption and permeability coefficients of PVA/PEI membranes in the presence
of THF and water. The membranes were found to have good potential for breaking the azeotrope of THF at 6% concentration of
water. An increase in PVA content in the blend caused a reduction in the flux and an increase in selectivity. Among the blends
tested in the study, the 5:1 PVA/PEI blend membrane showed the highest separation factor of 181.5, exhibited a flux of 1.28 kg/m2h for THF respectively at azeotropic feed composition. 相似文献
134.
135.
136.
Sandeep Peddi Rapur Ram Varalakshmi Devi Boreddy Sridhar Avssn Krishna Kishore Chennu Siva Kumar Vishnubotla 《Hemodialysis international. International Symposium on Home Hemodialysis》2014,18(1):192-194
We present an end‐stage renal disease patient on dialysis with fever. The primary source was right internal jugular vein catheter which had metastatic infections in the body probably via an arteriovenous communication in a cavity in left lung. Patient had right psoas muscle abscess and a left kidney abscess. An 18F‐fluorodeoxyglucose‐positron emission spectroscopy scan was done to find out left kidney abscess. A search of literature did not reveal many patients of psoas abscess secondary to infection of hemodialysis access. 相似文献
137.
Concept learning in robotics is an extremely challenging problem: sensory data is often high-dimensional, and noisy due to specularities and other irregularities. In this paper, we investigate two general strategies to speed up learning, based on spatial decomposition of the sensory representation, and simultaneous learning of multiple classes using a shared structure. We study two concept learning scenarios: a hallway navigation problem, where the robot has to induce features such as opening or wall. The second task is recycling, where the robot has to learn to recognize objects, such as a trash can. We use a common underlying function approximator in both studies in the form of a feedforward neural network, with several hundred input units and multiple output units. Despite the high degree of freedom afforded by such an approximator, we show the two strategies provide sufficient bias to achieve rapid learning. We provide detailed experimental studies on an actual mobile robot called PAVLOV to illustrate the effectiveness of this approach. 相似文献
138.
We explore tradeoffs between organization and number of ALUs and clock frequency in a stream processor. The tool provides candidate low-power configurations and estimates of their real-time performance. The tool relates instruction-level, subword, and data parallelism to functional units' organization and utilization. The exploration methodology is applicable to all embedded-processor designs in signal and media processing. 相似文献
139.
Chloridization is a potential method of beneficiating ilmenite. Studies on beneficiation of ilmenite were carried out by using
titanium chloride as the chloridizing agent in a laboratory scale fluidized bed reactor. Experiments were conducted on 1,
10, and 36 grams per batch scale, and the effect of the various rate determining steps on conversion was studied. Treated
particles of ilmenite were examined for chemical composition, surface properties, and structural changes. The paper presents
the experimental results on the chloridization treatment of natural and oxidized ilmenite. 相似文献
140.
The microstructure, tensile properties, and fractographic features of a near alpha titanium alloy, IMI 829 (Ti-6.lAl-3.2Zr-3.3Sn-lNb-0.5Mo-0.32Si)
have been studied after aging at 625 ° for 24 hours following solution treatment in the beta phase field at 1050 ° and cooling
at various rates (furnace, air, oil, or water). Transmission electron microscopy studies revealed that aging at 625 ° for
24 hours of this alloy had led to the precipitation of only one kind of silcide with a hexagonal structure (c = 0.36 nm andα = 0.70 nm). The precipitates are ellipsoidal in shape and their size depends on the cooling rate given to the alloy after beta
solution treatment. Extremely fine precipitation of Ti3Al phase has also been observed in the furnace cooled and aged condition. There is a significant improvement in both yield
and ultimate tensile strengths after aging of both the oilquenched and water-quenched specimens whereas it is minimal in the
case of furnace-cooled and air-cooled specimens. Aging the alloy has also resulted in a drastic reduction in both percentage
elongation and percentage reduction in area for all the conditions investigated. While the fracture surfaces of the unaged
specimens showed characteristic dimples, a large number of facets appeared in the fractographs of the aged specimens.
formerly with Banaras Hindu University, is with the National Metallurgical Laboratory, Jamshedpur, India. 相似文献