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1.
The contacts of single carbon nanotubes and bundles of carbon nanotubes with superconducting and metallic electrodes are investigated in order to create bolometers and electron coolers. Tunneling contacts of the carbon nanotubes with aluminum electrodes are obtained. The current-voltage characteristics of junctions are analyzed for temperatures from room temperature to 300 mK. The resistance of individual nanotubes is primarily determined by defects and is too large for applications. The use of the bundles of carbon nanotubes makes it possible to considerably reduce the resistance of the bolometer, which is determined by a small number of conducting tubes with good tunneling contacts with the electrodes. The energy gap is equal to hundreds and tens of millivolt in the former and latter cases, respectively. Structures containing bundles of carbon nanotubes can be described in a model with a Schottky barrier. The samples with bundles of carbon nanotubes exhibit the bolometric response to external high-frequency radiation at a frequency of 110 GHz with an amplitude up to 100 μV and a temperature voltage response to 0.4 mV/K. 相似文献
2.
Tor Schoenmeyr David Yu Zhang 《Journal of Algorithms in Cognition, Informatics and Logic》2005,57(2):130-139
The string matching with mismatches problem requires finding the Hamming distance between a pattern P of length m and every length m substring of text T with length n. Fischer and Paterson's FFT-based algorithm solves the problem without error in O(σnlogm), where σ is the size of the alphabet Σ [SIAM–AMS Proc. 7 (1973) 113–125]. However, this in the worst case reduces to O(nmlogm). Atallah, Chyzak and Dumas used the idea of randomly mapping the letters of the alphabet to complex roots of unity to estimate the score vector in time O(nlogm) [Algorithmica 29 (2001) 468–486]. We show that the algorithm's score variance can be substantially lowered by using a bijective mapping, and specifically to zero in the case of binary and ternary alphabets. This result is extended via alphabet remappings to deterministically solve the string matching with mismatches problem with a constant factor of 2 improvement over Fischer–Paterson's method. 相似文献
3.
Ross Anderson Cunsheng Ding Tor Helleseth Torleiv Klove 《Designs, Codes and Cryptography》1998,15(2):111-124
Previous researchers have designed shared control schemes with a view to minimising the likelihood that participants will conspire to perform an unauthorised act. But, human nature being what it is, systems inevitably fail; so shared control schemes should also be designed so that the police can identify conspirators after the fact. This requirement leads us to search for schemes with sparse access structures. We show how this can be done using ideas from coding theory. In particular, secret sharing schemes based on geometric codes whose dual [n,k,d] codes have d and n as their only nonzero weights are suitable. We determine their access structures and analyse their properties. We have found almost all of them, and established some relations among codes, designs and secret-sharing schemes. 相似文献
4.
S.G. Li G. Fu I. Reading S.B. Tor N.H. Loh P. Chaturvedi S.F. Yoon K. Youcef-Toumi 《Applied Physics A: Materials Science & Processing》2007,89(3):721-728
Micro powder injection molding (μPIM) is one of the potential processes for the mass production of metallic microstructures
and micro components. Here, μPIM is the miniaturization of conventional PIM, which involves four processing steps: mixing,
injection molding, debinding and sintering. This paper looks into the feasibility and effectiveness of μPIM as a key mass
production process for the fabrication of metallic micro components. For it to be an effective re-production process, it is
imperative to examine how well parts can be duplicated/fabricated from a master mold. In this work, the dimensional variation
of high-aspect-ratio micro-pillars arrays, in particular the dimensional shrinkage, global warpage, and surface roughness
at each stage of the μPIM process for a range of molding pressures, are quantified and compared in detail. The sensitivity
of the dimensional variation of the microstructures to the packing pressure is reported. The mechanism behind the dimensional
variation is analyzed.
PACS 81.20.Ev; 81.20.Hy; 81.70.Fy; 07.60.Ly; 81.05.-t 相似文献
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C. Andreoiu D. Rudolph I. Ragnarsson C. Fahlander R.A.E. Austin M.P. Carpenter R.M. Clark J. Ekman R.V.F. Janssens T.L. Khoo F.G. Kondev T. Lauritsen T. Rodinger D.G. Sarantites D. Seweryniak T. Steinhardt C.E. Svensson O. Thelen J.C. Waddington 《The European Physical Journal A - Hadrons and Nuclei》2002,14(3):317-348
High-spin states in 59Cu were populated using the fusion-evaporation reaction 28Si + 40Ca at a beam energy of 122 MeV. The Gammasphere Ge-detector array in conjunction with the 4π charged-particle detector array
Microball allowed for the detection of γ-rays in coincidence with evaporated light particles. The resulting extensive high-spin
decay scheme of 59Cu is presented, which comprises more than 320 γ-ray transitions connecting about 150 excited states. Their spins and parities
have been assigned via directional correlations of γ-rays emitted from oriented states. Average quadrupole moments of rotational
bands have been determined from the analysis of residual Doppler shifts. Shell model calculations in the fp shell are invoked to study some of the low-spin states, while the experimental characteristics of the rotational bands are
analyzed in the configuration-dependent cranked Nilsson-Strutinsky (CNS) approach.
Received: 15 February 2002 / Accepted: 23 April 2002 相似文献
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Tor Hurlen 《Journal of Electroanalytical Chemistry》1977,77(2):181-185
Combined thermodynamic and kinetic studies have yielded convenient single-ion activity coefficients for manganese(II), alkaline-earth, and chloride ions and standard exchange currents for the two steps of the Mn(Hg)/Mn(II) electrode in 0.005 M MnCl2+0.495 M MeCl2 (for Me=Mg, Ca, Sr, Ba, and Mn) at 25°C. The results indicate that the fall in mean ionic activity coefficient for the alkaline-earth chlorides along the sequence from magnesium to barium is carried to a larger extent by the cation than by the anion, that also the activity coefficient for the minority cation Mn(II) falls along this sequence, and that other than activity-coefficient effects on the Mn(Hg)/Mn(II) reactions appear only with barium ions, which retard the reactions additionally. The results are discussed with emphasis on ionic interactions and double-layer effects. 相似文献