Quenched sample room-temperature spectra

A similar study of the reaction of acetylene with iron supported on quartz was made by Maksimov et al. (240). The Mossbauer spectrum before reaction with acetylene was a spectral doublet characteristic of iron silicate. After reaction at 1270 K for 50 sec the sample was quenched to room temperature, and in the subsequent Mossbaucr spectrum a new peak was noted. The intensity of this peak increased with increasing reaction time up to 0.1 hr, after which time the intensity remained constant. In this case, it was only possible to study the rate of this surface reaction using a series of low-temperature quenches, since the characteristic reaction time was the order of time required to obtain the Mossbauer spectrum. 

Pressed pellets of BaTiC>3 were sintered in a platinum dish for six hours at 900°C in a controlled partial pressure of oxygen. The samples were quenched to room temperature, and the spectra recorded on a four-slit double-monochromator Raman spectrophotometer. An Ar+ laser with excitation at 514.5 nm was the source. The spectra were recorded at room temperature. Figure 4-30 shows the spectrum of BaTiC>3 whose Ba/Ti ratio is equal to 0.9999. The Raman spectrum is sensitive to the Ba/Ti ratio and theoxygen non-stoichiometry. The half-band width is variable as well as the intensity ratio of the 525 and 713 cm-1 bands. The ratio (I525/713) is at a minimum at the composition of 0.9999, and this can be observed in Fig. 4-31, which shows a plot of the intensity ratio (I525//713) vs. the Ba/Ti composition. 

Figure 18 represents the 2D H- Sn HMQC spectrum in the range of the oximic and aromatic protons, obtained respectively at room temperature from the equilibrium mixture (Fig ure 18a) and after heating the sample for 48 h at 55 °C, followed by quenching to room temperature prior to acquisition (Figure 18b). Spectrum 18(b) yields additional information about the species mi and m2 which are present in larger amounts at higher temperature.

Fig. 8. Raman spectra of N2O4 measured for different conditions. Top spectrum for sample heated at 8.3 GPa and quenched to room temperature. Middle spectrum for sample loaded to high pressure (> 6GPa) at low temperature, then warmed to room temperature and pressurized to 12.3 GPa. Bottom spectrum for sample loaded to low pressure (< 2 GPa) at low temperature, then warmed to room temperature and pressurized to 13.0 GPa. The inset shows the evolution of the characteristic peak at 2208 cm on compression under the same conditions under which the middle spectrum was obtained.

A comparison of neutron spectra with theory was made by Danner et al. (7). These workers obtained data for Marlex 6050 at temperatures below and above the glass-transition interval and the melting point, and for samples of branched, irradiated, and quenched polyethylene at room temperature. The spectrum at 100 K (Fig. 3) showed two peaks with shapes characteristic of acoustic modes at 550 and 200 cm" (peaks C and E in Fig. 3). Five additional peaks were observed at 1360,750,340,... 

The opto-electrical property of the ZnO/Pt IPMC was characterized using photoluminescence (PL). In order to understand the PL quenching phenomenon, measurements of the PL spectrum as a function of the potential were carried out with potential variation of 0-2.0 V. Fig 3.14 (a) shows the variation of PL spectra of the ZnO/PT IPMC recorded at the room temperature using an excitation wavelength of 280 nm. The spectra of the sample displays a broad emission band with some vibronic structure from 350 to 500 nm and the maximum emission wavelength is Xmax = 468 nm. The blue emission is believed to originate from intrinsic defects, particularly interstitial zinc [Fang et al. (2004)]. The maximum PL intensity is observed... 

Figure 11.7 shows the dynamic mechanical spectrum reported by Celli and Scandola [42] for PLLA after heating the sample at 200°C in order to erase the thermal history. The solid line refers to a sample quenched in a water-ice mixture after extrusion, while the broken line depicts an immediate rerun on the same sample, after cooling from 160°C. Below room temperature, no relaxation process is apparent in either curves, that is, the dynamic mechanical loss tangent is as low as 10 over the range —150-20°C [42]. The absence of any loss phenomena below Tg capable of mechanical energy dissipation is likely the reason for the observed brittleness of glassy PLLA and induces failure of lower molecular... 

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