Quartz ampoules

Interaction is violent and may be explosive, even with ice, oxygen being evolved [1]. Part of the water dropped into a flask of the gas was expelled by the violent reaction ensuing [2], An analytical procedure, involving absorption of chlorine trifluoride into 10% sodium hydroxide solution from the open capillary neck of a quartz ampoule to avoid explosion, was described [3], Inadvertent collection of chlorine trifluoride and ice in a cryogenic trap led to a small but violent explosion when the trap began to warm up overnight [4],... 

The resulting product has a low apparent density. Other synthesis techniques have been reported (192), mainly the reaction of a stoichiometric mixture of P3N5 and P4O10, heated at 780°C for 48 h, which directly results in a crystalline powder (193). Crystallization of X-ray amorphous PON produced using the other preparation methods is obtained after heating the powder in an evacuated quartz ampoule at 700-800°C for several days. 

Figure 6.14. Scheme of the experimental apparatus for gravimetric measurements described by Zavrazhnov et al. (2003) in their investigation of the phase composition control in chemical transport reactions. (1) quartz ampoule, (2) thermocouples, (3) two-zone furnace, (4) quartz rods, (5) wire for suspending the ampoule, (6) support, (7) weighing beam of the analytical balance,... 

Fig. 8. Apparatus for the preparation of single crystals by the Van Arkel procedure i. quartz ampoule 2. tube with iodine 3. feed material 4. RF heated W sphere or plate 5. resistance furnace 6. RF coil...

Preparation of Crystalline Silicon. Pure crystalline silicon is prepared in a quartz ampoule (Fig. 110). Put 2.5 g of amorphous silicon and 0.5 g of iodine preliminarily purified by sublimation... 

SEALED QUARTZ AMPOULE GaAs GROWTH SYSTEM... 

The thermal stability of the hydrogenated materials was estimated by measurements of gas thermodesorption. A piece of the sample cooled to liquid nitrogen under pressure was placed, in a liquid nitrogen bath, into a non-hermetic copper container, and the latter was moved into a quartz ampoule externally cooled with liquid nitrogen. The ampoule was connected to a vacuum system with the calibrated volume, the system was evacuated to 10-6 MPa, and then the ampoule was heated at a rate of 20 K/min. The pressure P of a gas evolved upon heating to 650°C was registered manually the sample was weighed after measurements. We call these dependences as a manometric curves . 

The mass spectra of the gases evolved from the deuterated SWNT sample heated in vacuum were measured with the MI 1201V mass spectrometer. Gas ionization in the ion source of the spectrometer was produced with a 70-eV electron beam. To obtain the gas phase, the sample was placed in a quartz ampoule of a pyrolyzer that was connected to the injection system of the mass spectrometer through a fine control valve. Then the ampoule was evacuated to a pressure of about 2-x 10-5 Pa in order to remove the surface and weakly bound impurities from the sample. After the evacuation, the ampoule was isolated from the vacuum system and the sample was heated to 550°C in five steps. At each step, the sample was kept at a fixed temperature for 3 h then the fine control valve was open and the mass-spectrometric analysis of the gas collected in the ampoule was performed. After the analysis, the quartz ampoule was again evacuated, the valve was closed, and the sample was heated to the next temperature. The measurements were carried out over the range 1 < m/z < 90, where m is the atomic mass and z is the ion charge. The spectrometer resolution of about 0.08% ensured a reliable determination of the gas-phase components. 

Solutions of2g of 1,3-D in 100 mL of different solvents were placed into quartz ampoules and irradiated by mercury lamp (1200W) for 4hr. No electrolysis was used in these experiments. 

Diffusion couples were encapsulated in quartz ampoules filled with argon. Their annealing was carried out in electric-resistance furnaces, with the temperature deviations from the required value, not exceeding 1°C. After annealing, the couples were cut along the cylindrical axis and... 

Mass-spectra of the gases eliminated from the specimens under elevated temperature were taken on mass-spectrometer MI-1201B (Sumy, USSR). The gas in ion source was ionized by electron impact (electron energy 70eV). Samples were placed in the quartz ampoule equipped by adjustable heater and connected through the needle valve with inlet system of mass-spectrometer. The sample was pumped out during one day up to the pressure 2xlO"5Pa to remove weakly bounded surface... 

The starting alloy NbVCo was melted from pure metals by using electrical furnace under inert atmosphere and quenched in evacuated quartz ampoule at 800°C temperature during 240 hours. Hydride was synthesized at high pressure apparatus... 

Irradiations. Samples were neutron-irradiated at the Oak Ridge and Chalk River facilities and in the MTR reactor at Arco, Idaho. In the first two cases, powder samples were submitted as such, while for the MTR irradiations both loose samples—i.e., in contact with air—and samples in evacuated quartz ampoules were submitted. Exposures are given as integrated nvt values. No special temperature control was attempted, but irradiation temperatures were probably not over 150° C. at Oak Ridge, and less at the other installations. 

Single crystal, c-cut ZnO samples were purchased from Cermet, Inc. Samples were sealed in quartz ampoules along with hydrogen or deuterium gas. In addition, ZnO powder was placed in the ampoule, in order to prevent the decomposition of the ZnO crystal due to hydrogen reduction. Hydrogen diffusion occurred at a temperature of 700-800°C for 10-100 hr, followed by a rapid quench to room temperature by immersion of the ampoule in water. The sample was then retrieved by breaking the ampoule. 

Direct synthesis of the elemental constituents in evacuated quartz ampoules was used in most reported cases. The ampoules with the mixtures of elements were heated to different preset maximum temperature, for example 1420 K, and were kept at this temperature for a few hours. Afterward, the ampoules were cooled slowly to a respective annealing temperature, for example 870 K, and annealed at this temperature for many hours. In some cases, the flux method was used. Detailed experimental conditions can be found in the original cited papers. 

The samples used for irradiation must withstand the temperature and the radiation in the reactor without decomposition. In general, they are encapsulated in aluminium cans or in quartz ampoules which are introduced in irradiation tubes or directly into special positions within the reactor. 

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