Suprasil

Fig. 7. Optical density of solid Coo on Suprasil based on two different optical techniques (+, ). For comparison, the solution spectrum for Coo dissolved in decalin (small dots) is shown. The inset is a plot of the electron loss function -7m[(l + e)] vs E shown for comparison (HREELS) [78].

The majority of detectors, which are employed for the measurement of absorption, employ UV glass (e.g. Suprasil). AU type S-5 photomultiphers possess sheaths of this material, so that they ought to be usable in the far UV region if N2 purging IS employed (to remove O2) (Tab. 4). 

Benzene, benzene-t/i, CFCI3 and CF3CCI3 were obtained commercially and were not further purified. Solutions of c a 0.3 - 1 volume % of benzene in CFCI3 were prepared in suprasil quartz tubes of 4 mm outer diameter on a vacuum line. The samples were degassed and sealed under vacuum (< 10-4 -porr). Polycrystalline samples were prepared by rapid freezing in liquid nitrogen. The samples were irradiated at 77 K for 5 minutes at an approximate dose rate of 250 G/min. using the radiation from an X-ray tube with a W anode operated at 70 kV and 20 mA. 

Instrumentation. UV-Vis spectra were recorded at 30°C over a range of 200-900 mn on a Varian Cary 50 with WinUV Analysis Suite software, Vers. 3.0, using Suprasil ... 

All zeolite samples ( 1,4g) were used after dehydration procedure at 773 K under Ar. Then, weighted amount of DPP corresponding to 1 molecule per zeolite unit cell (UC) was added under dry argon at 293 K and the powders were shaken in the dark. Powders were transferred under dry argon in quartz glass Suprasil cell or in cylindrical EPR quartz tube and sealed. 

Figure 6. Spectral attenuation of PCS fibres drawn from silica (Optran UV and Suprasil 300).

Figure 21. Spectral transmission of a 100-nm layer of hydrogenated amorphous Si deposited by plasma CVD of a silanethelium mixture on a Suprasil quartz substrate. (Reproduced with permission from Ref. 53.)...

Industrial wastewater may be colored and color removal may be required to comply with regulation. Coque et al. describe how various discoloration methods were studied with standard azo dyes solutions and an industrial wastewater from the paper industry as model systems. The liquids were recirculated between the photochemical discoloration reactor and an at-line spectrophotometer (Suprasil quartz cell, path length 2 or 10mm, resp.). A discoloration yield x was calculated in CIE L a b space, which permitted monitoring the process and determining completion in an easily implemented manner. 

Pulse radiolysis was performed using e from a linear accelerator at Osaka University [42 8]. The e has an energy of 28 MeV, single-pulse width of 8 nsec, dose of 0.7 kGy, and a diameter of 0.4 cm. The probe beam for the transient absorption measurement was obtained from a 450-W Xe lamp, sent into the sample solution with a perpendicular intersection of the electron beam, and focused to a monochromator. The output of the monochromator was monitored by a photomultiplier tube (PMT). The signal from the PMT was recorded on a transient digitizer. The temperature of the sample solution was controlled by circulating thermostated aqueous ethanol around the quartz sample cell. Sample solution of M (5 x 10 -10 M) was prepared in a 1 x 1 cm rectangular Suprasil cell. 

III flame hydrolysis <20 600-1200 50-100 <1 170 Coming 7940, Dynasil 1000, Shinetsu P-10, Spectrosil, Suprasil, NSG-ES... 

ESR Measurements. Samples were sealed in 3-mm. o.d. Suprasil quartz tubes after thorough degassing of both the wool and monomer... 

Table IV. Typical Impurity Levels of a 2.77-g Suprasil Vial...

Samples which were counted in polyethylene and quartz vials required corrections for the impurity content of the vials. Standard libraries of vial and blank filter paper corrections were added to SPECTRA (see Tables II, III, and IV). We used indicators in the input data to each computer calculation to call out the proper correction library. The code used corrections for polyethylene vials, Suprasil vials, Whatman-41 filters (25.8 cm2), and combinations. The computer also did not print the value for an element in a sample if the microgram quantity was within two times the microgram value of the vial or filter paper. The value output was listed as less than the vial or filter paper value, corrected to proper units. With this restriction, some data were lost, but very small values which were the difference between two larger numbers were eliminated. For example, if a volatile sample plus vial gave a chlorine value of 9.4 fig, the chlorine value output by the computer for the sample would be less than 9.0 fig (referring to chlorine in Table V) rather than the difference of 0.4 fig. If the sample plus vial gave a chlorine value of 20 fig, the value output by the computer would be 11 fig. 

The UV-Vis spectra were recorded on a Perkin-Elmer Lamda 16 spectrometer in the diffuse reflectance mode. ESR spectra were recorded at X-band on a Bruker ESP 300 spectrometer at 77 K The samples were loaded into 3 mm o.d by 2 mm i d. Suprasil quartz tubes, which were evacuated to a final pressure of 10 5 kPa at 695 K overnight. The activated samples were sealed, immersed in liquid nitrogen and finally exposed to y-irradiation of a 6(lCo source to a total dose of 1.1 Mrad at a dose rate of 0.18 Mrad h 1 before the ESR experiments... 

Phosphorescence spectra (uncorrected, front face) were recorded on a Perkin-Elmer LS-5 fluorescence spectrometer using a pulsed excitation source ( 10 ps) and gated detection. The instrument was controlled by a P-E 3600 data station. The samples were typically excited at 313 nm using the instrument s monochromator and an additional interference filter. Excitation and emission bandpasses were 2 nm. Typically the emission spectra were recorded using a 50 ps delay following excitation and a 20 ps gate. The samples were contained in cells made of 3x7 mm2 Suprasil tubing, under a continuous stream of N2, 02 or 02/N2 mixtures of known composition. 

Solutions were flowed through a suprasil flat cell (0.1 mm thickness) at rates between 0.1 - S.O mL/min in order to minimize any interference from signals produced by secondary photolysis of products. Time-resolved polarization evolution profiles for the formation and relaxation of the polarized radicals were measured at a constant magnetic field and monitored by both a Hitachi 40 MHz digital oscilloscope and a Stanford Research Systems gated integrator/boxcar averager at 5 ns resolution, and both coupled to a 486 PC desk-top microcomputer for analysis. 

Photoirradiation and ESR Measurements. The samples of cellulose and cellulose derivatives were packed uniformly into clear fused Suprasil quartz tubes (O.D. 4 mm), which did not produce any ESR signal during the irradiated sequences. The quartz tubes containing the samples were evacuated to a constant pressure (10 6 mm Hg) and sealed. The source of ultraviolet irradiation was a high pressure mercury-xenon compact arc lamp (Conrad Hanovia type 901 BOOH, 200 W) which... 

III SiCl4 Flame hydrolysis Metals <1 1000 Suprasil Spectrosil CGW 7940 Dynasil Synsil ... 

IV SiCl4 Plasma oxidation Cl 200 Metals <1 <1 Suprasil Spectrosil WF Coming 7943... 

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