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ref: -0 tags: carbon nanotube densification conductivity strength date: 02-23-2017 02:52 gmt revision:2 [1] [0] [head]

Super-strong and highly conductive carbon nanotube ribbons from post-treatment methods

  • Conductivity of 1.2e6 S/m, about that of stainless steel.
    • 500 x 500nm wire, length 1cm will have a resistance of 40k.
  • Aerogel method: methane + ferrocene + thiophene + hydrogen.
    • Resulting in ~ 18% Fe, multi-walled carbon nanotubes, diameter 15nm, 15-20 walls.
  • Densified with a stainless-steel spatula on regular paper.
    • Resulting in ribbons 22um wide, 650nm thick.
  • Very high tensile strength, up to 5.2 GPa; moduls ~ 266 GPa.

High-strength carbon nanotube fibre-like ribbon with high ductility and high electrical conductivity

  • Slightly higher conductivity, 1.82 - 2.24e6 S/m.
  • Rolled until it was 500nm thick!
  • Spun from an aerogel (!!) using ethanol + ferrocent + thiophene.

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ref: -0 tags: carbon fiber pitch based tensile strength date: 02-04-2017 00:07 gmt revision:4 [3] [2] [1] [0] [head]

Contenders for high-modulus pitch-based carbon fiber: "

CorpModelYoung's modulusTensile StrengthDiameter Elongation at break
Nippon Graphite Fiber CoGranoc XN-90860 GPa3.43 GPa10 um0.4%
Mitsubishi RayonK13D2U940 GPa3.21 GPa11 um0.36%
Cytec ThornelP-120830 GPa2.41 GPa??0.3-0.5%
Cytec ThornelK1100965 GPa3.10 GPa10 um??

Tensile and Flextural Prperties of single carbon fibers

  • High modulus pitch-based carbon fibers have quite low compressive and shear strengths. The flexural strength could be affected strongly by its low strength under compression and shear loading.

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ref: Najafi-1990.05 tags: Najafi Michigan probe silicon strength electrodes recording MEA date: 01-03-2012 22:45 gmt revision:5 [4] [3] [2] [1] [0] [head]

PMID-2345003[0] Strength characterization of silicon microprobes in neurophysiological tissues.

  • These active (with amplification/buffering circuitry) electrodes were around since 1990! It's been a while, and at least the devices are commercially available now.
  • Show that thin-film silicon is remarkably flexible and tough - about six times as strong as bulk silicon.
  • Have developed a silicon probe with an integrated phosphorous-doped polysilicon strain guague - nice.

____References____

[0] Najafi K, Hetke JF, Strength characterization of silicon microprobes in neurophysiological tissues.IEEE Trans Biomed Eng 37:5, 474-81 (1990 May)

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ref: Huber-2004.07 tags: sleep REM SWS wilson synaptic strength date: 04-01-2009 17:50 gmt revision:2 [1] [0] [head]

http://www.the-scientist.com/2009/04/1/34/1/ -- good layperson-level review of the present research on sleep. Includes interviews with Strickgold and other prominents. References:

http://www.the-scientist.com/2009/04/1/15/1/ -- points out that Western sleep style is a relative outlier compared to sleeping in other cultures. More 'primitive' cultures have polyphasic sleep, with different stages of alertness, dozing, napping, disengaged, vigilance, etc.

  • Quote: Other cultures tend towards "multiple and multiage sleeping partners; frequent proximity of animals; embeddedness of sleep in ongoing social interaction; fluid bedtimes and wake times; use of nighttime for ritual, sociality, and information exchange; and relatively exposed sleeping locations that require fire maintenance and sustained vigilance."

____References____

[0] Huber R, Ghilardi MF, Massimini M, Tononi G, Local sleep and learning.Nature 430:6995, 78-81 (2004 Jul 1)
[1] Klintsova AY, Greenough WT, Synaptic plasticity in cortical systems.Curr Opin Neurobiol 9:2, 203-8 (1999 Apr)
[2] Vyazovskiy VV, Cirelli C, Pfister-Genskow M, Faraguna U, Tononi G, Molecular and electrophysiological evidence for net synaptic potentiation in wake and depression in sleep.Nat Neurosci 11:2, 200-8 (2008 Feb)
[3] Pavlides C, Winson J, Influences of hippocampal place cell firing in the awake state on the activity of these cells during subsequent sleep episodes.J Neurosci 9:8, 2907-18 (1989 Aug)
[4] Pompeiano M, Cirelli C, Arrighi P, Tononi G, c-Fos expression during wakefulness and sleep.Neurophysiol Clin 25:6, 329-41 (1995)
[5] Hill S, Tononi G, Modeling sleep and wakefulness in the thalamocortical system.J Neurophysiol 93:3, 1671-98 (2005 Mar)
[6] Aton SJ, Seibt J, Dumoulin M, Jha SK, Steinmetz N, Coleman T, Naidoo N, Frank MG, Mechanisms of sleep-dependent consolidation of cortical plasticity.Neuron 61:3, 454-66 (2009 Feb 12)