In situ Fourier transform infrared (FT-IR) measurement has been performed in a metal-organic chemical vapor deposition (MOCVD) technique using a source material which is solid at room temperature. First, methods to introduce purge gas into a CVD reactor to prevent raw materials and thermally decomposed products from depositing onto the KBr windows were examined. We were able to separate spectra of gaseous pure source materials and those of species adhered on the KBr windows under the optimum flow rate of purge gas. Then, in situ IR spectra of Cu(DPM)2 were measured in detail in the CVD reactor. The results of measured spectra showed that no change of the chelate carbonyl region occurred, and that two new peaks appeared, of which intensities increased with the increase of the substrate temperature. The dependence corresponded well to the change of the atomic composition in the films deposited on SiO2.
Optical emission spectra from a glow-discharge plasma in the vapors of β-diketonate chelates of Ba, Y and Cu element have been measured. They show great changes depending on the temperature of the source-gas oven. In the case of Ba(DPM)2, for example, intensity of the Ba+ emission lines increases drastically at above 220°C, when compared to neutral lines. Referring to the data of thermal analysis and IR absorption experiment, this corresponds to the development of decomposition of the source material. The present experiment opens a future possibility of optical diagnostics to determine the optimum gas feeding condition in the preparation of high-T
c superconducting films by the MOCVD technique.
Vascular and clinical assessments of arterio-venous fistula (AVF) function and access are important in patients undergoing or preparing to undergo renal dialysis. Objective assessment techniques include colour duplex ultrasound and more recently medical infrared thermography. Ideally, these should help assess problems relating to fistula failure or to vascular steal from the hand which can result from excessive fistula blood flow. The clinical value of thermography, as yet, has not been assessed for this patient group. The aims of this study were therefore to investigate the relationships between thermography skin temperature measurement and (a) quantitative ultrasound measurement of AVF blood flow, and (b) qualitative clinical assessment of vascular steal from the hands. Fifteen adult patients underwent thermal imaging of the upper limbs, colour duplex ultrasound to derive AVF blood flow from brachial artery blood flow measurements, and a clinical evaluation for vascular steal. Temperature measurements were extracted from the thermograms, including bilateral arm and hand (Fistula − Non-Fistula) differences, for comparison with derived AVF blood flow and steal grading. Derived AVF blood flow ranged from 30 to 1950 ml min −1 , with a mean rate close to one litre per minute. Thermography detected the warmer superficial veins in proximity to the patent fistulas, with bilateral differences in fistula region skin temperature correlated with derived AVF blood flow (using maximum temperature measurements the correlation was +0.71 [p < 0.01]; and using mean temperature measurements the correlation was +0.56 [p < 0.05]). When thermography measurements were compared with the clinical assessment of steal the mean hand temperature differences separated steal from non-steal patients with an accuracy of greater than 90%. In summary, we have now demonstrated the potential clinical
Precursors for Silicon nitride films prepared by mixing SiH2Cl2 with NH3 were investigated by in situ Fourier-transform infrared spectroscopy (FT-IR) and mass spectrometry. The FT-IR spectral analysis results indicated that the Cl was removed from SiH2Cl2 by mixing SiH2Cl2 with NH3 at room temperature (R.T.). The analysis results also indicated the existence of radicals which had the chemical bond Si–N. The mass spectral analysis results indicated the existence of the radicals with the mass number of 45–47. From these results, it was concluded that the precursors of SiNH
x
for SiN films were formed by mixing SiH2Cl2 with NH3.
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