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151.
Iain A. Anderson Thom Hale Todd Gisby Tokushu Inamura Thomas McKay Benjamin O’Brien Scott Walbran Emilio P. Calius 《Applied Physics A: Materials Science & Processing》2010,98(1):75-83
Desirable rotary motor attributes for robotics include the ability to develop high torque in a low mass body and to generate
peak power at low rotational speeds. Electro-active polymer artificial muscles offer promise as actuator elements for robotic
motors. A promising artificial muscle technology for use as a driving mechanism for rotary motion is the dielectric elastomer
actuator (DEA). We present a membrane DEA motor in which phased actuation of electroded sectors of the motor membrane impart
orbital motion to a central drive that turns a rotor. The motor is inherently scalable, flexible, flat, silent in operation,
amenable to deposition-based manufacturing approaches, and uses relatively inexpensive materials. As a membrane it can also
form part of the skin of a robot.
We have investigated the torque and power of stacked membrane layers. Specific power and torque ratios when calculated using active membrane mass only were 20.8 W/kg
and 4.1 Nm/kg, respectively. These numbers compare favorably with a commercially available stepper motor. 相似文献
152.
Francesco Fedele Melissa McKay George F. Pinder Joseph F. Guarnaccia 《国际流体数值方法杂志》2004,44(12):1337-1354
The classical collocation method using Hermite polynomials is computationally expensive as the dimensionality of the problem increases. Because of the use of a C1‐continuous basis, the method generates two, four and eight unknowns per node for one, two and three‐dimensional problems, respectively. In this paper we propose a numerical strategy to reduce the nodal unknowns to a single degree of freedom at each node. The reduction of the unknowns is due to the use of Lagrangian polynomials to approximate the first‐order derivatives over the minimal compact stencil surrounding each node. For the solvability of the problem the reduction of the number of collocation equations is done by a nodal weighting strategy. We have applied the proposed approach to enhance the efficiency of a collocation‐based multiphase flow and transport simulator. Benchmark cases illustrate the higher performance of the new methodology when compared to classical Hermite collocation. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
153.
Cyclopentenone and dichlorocycloalkenes give [2+2] adducts whose stereochemistry (from modern NMR) is mostly cis, anti, cis; cis, syn, cis minor adducts are also found. Cophotolysis of dichlorocyclohexene and cycloheptanocyclopentenone does not give any adduct. 相似文献
154.
Benjamin McKay 《Proceedings of the American Mathematical Society》2007,135(2):597-603
An isomorphism of symplectically tame smooth pseudocomplex structures on the complex projective plane which is a homeomorphism and differentiable of full rank at two points is smooth.
155.
Mitigation of lunar dust on solar panels and optical elements utilizing electrostatic traveling-wave 总被引:1,自引:0,他引:1
A system for removing lunar dust from the surface of solar panels and optical elements is of great importance for lunar exploration. We have developed a method of removing lunar dust using electrostatic traveling-waves generated by four-phase rectangular voltage applied to a transparent conveyer consisting of parallel ITO (indium tin oxide) electrodes printed on a glass substrate. On the basis of basic investigations, we have demonstrated the removal of actual lunar dust. A numerical investigation predicts that the performance will improve in the low-gravity environment on the Moon. 相似文献
156.
157.
Let s and t be vectors of positive integers with the same sum. We study the uniform distribution on the space of simple bipartite graphs with degree sequence s in one part and t in the other; equivalently, binary matrices with row sums s and column sums t . In particular, we find precise formulae for the probabilities that a given bipartite graph is edge‐disjoint from, a subgraph of, or an induced subgraph of a random graph in the class. We also give similar formulae for the uniform distribution on the set of simple directed graphs with out‐degrees s and in‐degrees t . In each case, the graphs or digraphs are required to be sufficiently dense, with the degrees varying within certain limits, and the subgraphs are required to be sufficiently sparse. Previous results were restricted to spaces of sparse graphs. Our theorems are based on an enumeration of bipartite graphs avoiding a given set of edges, proved by multidimensional complex integration. As a sample application, we determine the expected permanent of a random binary matrix with row sums s and column sums t . © 2009 Wiley Periodicals, Inc. Random Struct. Alg., 2009 相似文献
158.
159.
We examine the dependence of event rates at neutrino telescopes on the neutrino-nucleon cross section for neutrinos with energy above 1 PeV, and contrast the results with those for cosmic ray experiments. Scaling of the standard model cross sections leaves the rate of upward events essentially unchanged. Details, such as detector depth and cross section inelasticity, can influence rates. Numerical estimates of upward shower, muon, and tau event rates in the IceCube detector confirm these results. 相似文献
160.
Orce JN Holt JD Linnemann A McKay CJ Lesher SR Fransen C Holt JW Kumar A Warr N Werner V Jolie J Kuo TT McEllistrem MT Pietralla N Yates SW 《Physical review letters》2006,97(6):062504
The low-spin structure of 93Nb has been studied using the (n,n'gamma) reaction at neutron energies ranging from 1.5 to 3 MeV and the 94Zr(p,2ngamma)93Nb reaction at bombarding energies from 11.5 to 19 MeV. States at 1779.7 and 1840.6 keV, respectively, are proposed as mixed-symmetry states associated with the pi2p(1/2)-1x(2(1),MS+,94Mo) coupling. These assignments are derived from the observed M1 and E2 transition strengths to the 2p(1/2)-1x(2(1)+,94Mo) symmetric one-phonon states, energy systematics, spins and parities, and comparison with shell model calculations. 相似文献