Spectra filament

Dyneema yarns have filament titers of 1-2 dtex. Spectra filaments are coarser (4-11 dtex). Filaments of 2 dtex with a density of 0.97 g cm have a diameter of 16 xm. How is this diameter produced If we assume a draw ratio of 100 and a concentration of 10% we can calculate the diameter of the undrawn gel filaments from Eq. (10) to be Dgel,undrawn = f drawn(DR/ ) = 16(100/0.1) = 506 gm. We... 

To use the DCI probe, 1-2 xL of the sample (in solution) are applied to the probe tip, composed of a small platinum coil, and after the solvent has been allowed to evaporate at room temperature, the probe is inserted into the source. DCI probes have the capability of very fast temperature ramping from 20 to 700 °C over several seconds, in order to volatilise the sample before it thermally decomposes. With slower temperature gradients, samples containing a mixture of components can be fractionally desorbed. The temperature ramp can be reproduced accurately. It is important to use as volatile a solvent as possible, so as to minimise the time required to wait for solvent evaporation, which leaves a thin layer of sample covering the coil. The observed spectrum is likely to be the superposition of various phenomena evaporation of the sample with rapid ionisation direct ionisation on the filament surface direct desorption of ions and, at higher temperature, pyrolysis followed by ionisation. 

Photo-oxidation or reduction is often found if the complex is irradiated in the charge-transfer bands (see above) photo-oxidation of the metal occurring if the transition is M - -L. Thus the photochemical generation from Ir(IV)Cl6 of a species active in forcing filaments of E. coli may well involve the photoreduction of Ir(IV) to Ir(III) since the intense bands in the visible spectrum of Ir(IV)Clcharge-transfer bands. A report has appeared of the photo-aquation of IrCl -(43). 

FIGURE 12.4 Lycopene photodegradation in 0.02 M Triton X-100 aqueous solutions illuminated with a 150 W (> 380 nm) filament lamp. Inset evolution of the difference absorption spectrum (AA). 

Fig. 8. Difference spectrum (green irradiated minus red irradiated) of phycochrome c (solid line), action spectrum for induction of filamentous growth of Nostoc muscorum (dotted line), and action spectrum for inhibition of C-phycoerythrin synthesis in Tolypothrix tenuis (dashed-dotted line). Abscissa wavelength in nm Ordinates relative absorbance change und relative action (after Bjorn and Bjorn 5))...

Although the action spectra for the induction of the filamentous growth in Nostoc are shown to coincide with the difference spectrum between the two absorption forms of phycochrome c (see above), no molecular mechanism for the transduction has yet been suggested. 

Figure 5.1 depicts filamentation that has been imaged during the propagation of ultrashort pulses through a crystal of BaF2. The spectrum associated with the filaments that are seen shows a predominantly blue emission [39] that is centered on 330 nm, one of the two luminescence bands (the other one... 

Material like sapphire, which is a uniaxial crystal, does not show nonlinear fluorescence, and direct visualization of filaments is, consequently, not an option. However, the effect of rotation of plane polarization can also be probed in such materials by monitoring the spatial size of the white light disc, and of the spectrum of the super continuum that is produced. Figure 5.3 depicts some typical results obtained with 3 mm long sapphire crystals. The extent of the supercontinuum spectrum is seen to vary as a function of polarization angle. The supercontinuum spectrum has two components [39] symmetric broadening about the incident wavelength that is essentially ascribable to... 

Fig. 6. Ure2p filaments are infectious. (A, B) Negatively stained micrographs of Ure2p filaments (A) before and (B) after sonication, which was found to be necessary for effective transformation of filaments. (C) Color spectrum of [URE3] variants in randomly chosen colonies after transformation of yeast cells with Ure2p filaments. (D) Conversion efficiency to [URE3] status is dependent on Ure2p filament concentration. All panels adapted from Figure 2 of Brachmann et al (2005).

Using a high-resolution spectrograph and a Fabry-Perrot interferometer, Gunther eta/. 727) resolved a number of equidistant components with a mean separation of 0.04 cm" in the stimulated Raman spectrum of CSj, which can be attributed to resonant modes in single medium-scale filaments of self-trapped radiation within the liquid. 

An electrically heated filament, usually tungsten, emits electrons, which are accelerated by a high potential difference (20-50 kV) and allowed to strike a metal target or anode which is water cooled (Figure 2.1 (a)). The anode emits a continuous spectrum of white X-radiation but superimposed on this are sharp, intense X-ray... 

The gas stream from the inlet system (Fig. 2.2) enters the ionization chamber (operated at a pressure of about 10-6 — 10"5 torr) in which it is bombarded at right angles by an electron beam emitted from a hot filament. Positive ions produced by interaction with the electron beam are forced through the first accelerating slit by a weak electrostatic field. A strong electrostatic field then accelerates the ions to their final velocities. To obtain a spectrum, the applied magnetic field is increased, bringing successively heavier ions into the collector slit. A scan from mass (strictly m/z see above) 12 — 500 may be performed in seconds. 

Hafnium nitride s high emissivity in the visible spectrum at high temperature has led to a proposed use (52) as a coating on incandescent light filaments to improve visible light output. 

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