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61.
Shanju Zhang Lingbo Zhu Marilyn L. Minus Han Gi Chae Sudhakar Jagannathan Ching-Ping Wong Janusz Kowalik Luke B. Roberson Satish Kumar 《Journal of Materials Science》2008,43(13):4356-4362
We report continuous carbon nanotube (CNT) fibers and yarns dry-drawn directly from water-assisted chemical vapor deposition
(CVD) grown forests with about 1-mm height. As-drawn CNT fibers exist as aerogel and can be transformed into more compact
fibers through twisting or densification with a volatile organic liquid. CNT fibers are characterized by scanning electron
microscopy, X-ray photoelectron spectroscopy, Raman microscopy, and wide-angle X-ray diffraction. Mechanical properties and
electrical conductivity of the post-treated CNT fibers are investigated. The resulting fibers show the work of rupture of
30 J/g and DC electrical conductivity of 5.0 × 104 S/m. 相似文献
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Two fast tree-creation algorithms for genetic programming 总被引:1,自引:0,他引:1
Genetic programming is an evolutionary optimization method that produces functional programs to solve a given task. These programs commonly take the form of trees representing LISP s-expressions, and a typical evolutionary run produces a great many of these trees. For this reason, a good tree-generation algorithm is very important to genetic programming. This paper presents two new tree-generation algorithms for genetic programming and for “strongly typed” genetic programming, a common variant. These algorithms are fast, allow the user to request specific tree sizes, and guarantee probabilities of certain nodes appearing in trees. The paper analyzes these two algorithms, and compares them with traditional and recently proposed approaches 相似文献
65.
Dislocation structures in as-received and plastically deformed commercial α2 + B2 and homogeneous ordered B2 intermetallic titanium aluminide alloys (“super-α2”) were characterized with transmission electron microscopy. Thin foils prepared by twin-jet electropolishing and ion beam thinning were found to yield different deformation structures. Electropolished foils were found to contain lath-like bands of dislocation loops with
Burgers' vectors (b) in the B2 phase that were actually thinning artifacts. Dislocations in lightly deformed ion-beam-thinned foils appeared to be predominantly screw dislocations with 相似文献
66.
M.D. Blumenthal B. Kaestner L. Li S. Giblin T.J.B.M. Janssen M. Pepper D. Anderson G. Jones D.A. Ritchie 《Microelectronics Journal》2008,39(3-4):365-368
We present the first results on electron transport through a tuneable-barrier double quantum dot electron pump. This device could yield twice the current to a single-dot pump previously reported [M.D. Blumenthal, B. Kaestner, L. Li, S. Giblin, , T.J.B.M. Janssen, M. Pepper, D. Anderson, G. Jones, D.A. Ritchie, Gigahertz quantized charge pumping, Nat. Phys. 3 (2007) 343], at the same operating frequency. The two quantum wires forming the device were not sufficiently homogeneous for pumping to be observed through both dots simultaneously, but sufficient homogeneity should be attainable in future batches of devices. 相似文献
67.
A series of novel pi (π) conjugated polymers, originating from the archetypical Polyphenylene vinylene, in which the phenyl units are successively replaced by the larger naphthyl and anthryl acene units, were previously found to have a well-defined relationship between their relative fluorescence yields and their vibrational characteristics, as determined by Raman spectroscopy. In this study the Strickler-Berg equation is used to probe the influence of continual substitution of higher order acene units into the conjugated backbone in terms of the variation of the radiative and non-radiative rates. The deconvolution of the radiative and non-radiative rates enables the correlation of the reduction of the Raman intensity and concomitant increase in the fluorescence yield with the reduction of the non-radiative rate. This confirms that the reduction of the non-radiative rate is the dominant process introduced by the vibrational confinement originating from systematic substitution of higher order acene units into the polymer backbone. 相似文献
68.
Closed-Loop Control of an Anesthesia Delivery System: Development and Animal Testing 总被引:1,自引:0,他引:1
Ritchie R. Gilbert Ernst Edward A. Pate Brian L. Pearson J. D. Sheppard Louis C. 《IEEE transactions on bio-medical engineering》1987,(6):437-443
An anesthesia system which integrates closed-loop control of ventilation, oxygen, nitrous oxide, and anesthetic agent delivery into a closed breathing circuit is described. Breathing circuit volume is regulated by controlling the sum of oxygen and nitrous oxide flow, and oxygen concentration in the breathing circuit is regulated by controlling the ratio of oxygen flow to the sum of oxygen and nitrous oxide flow. End-tidal anesthetic agent concentration is regulated by controlling the agent delivery, and end-tidal carbon dioxide concentration is regulated by controlling the ventilation. After tuning the ventilation and anesthetic delivery controllers in preliminary trials in ten dogs, the system was tested and evaluated in five dogs. All control loops were stable and exhibited time responses to step changes in setpoint or external disturbances which were clinically acceptable. The system makes available the advantages of closed-system anesthesia without encumbering the anesthesiologist with the control tasks associated with the technique. 相似文献
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