Vacuum vaporization experiments

Smooth and uniform polymer surface after vacuum plays a key role to ensure good OFRR sensing performance. We have observed in experiments that toluene after vacuum is prone to leave a number of cavities of a few micrometers in diameter on the surface. These cavities will induce additional scattering loss for the WGMs in the OFRR, which greatly degrade the g-factor, and hence the detection limit of the OFRR vapor sensor. Moreover, these small cavities have different adsorption characteristics compared to smooth polymer surface. Vapor molecules may be retained for a longer time at the cavity, which increases the response time and recovery time. Acetone and methanol are found to be better candidates for solvents because they usually leave uniform and smooth surface after vacuum. 

To examine how and why the surface ethanol reaction is assisted by the gas-phase ethanol, the following experiments were conducted in a closed circulating reactor. Ethanol vapor was first admitted onto the dioxoniobium monomer catalyst (1), Si0 2Nb(=0)2, to form the niobium ethox-ide (2), Si0 2Nb(=0)(0H)(0C2H5), at 373 K, followed by evacuation, and then the system was maintained at 523 K for 10 min, where no H2 evolution was observed because the niobium ethox-ide (2) was stable up to 600 K in vacuum. After the confirmation of no H2 formation from the preadsorbed ethanol (2), tert-butyl alcohol was introduced to the system at 523 K, which led to a stoichiometric evolution of H2 and CH3CHO. As the fert-butyl alcohol molecule has no extractable a-hydrogen, it is evident that both H2 and CH3CHO were produced from the preadsorbed ethanol by the assistance of the postdosed tert-butyl alcohol. 

The role of the matrix in MALDI is analogous to that in FAB (Chap. 9.3.1). Different from FAB, MALDI matrices are generally crystalline solids of low vapor pressure in order not to be volatalized in the ion source vacuum. While basically any liquid can serve as a FAB matrix, the matrix in MALDI has to absorb light of the wavelength which is intended to be used for the experiment. [63] In UV-... 

This discussion cannot provide exhaustive coverage of the many and varied application fields fbr oil-filled vacuum pumps in the chemicals industry. Our many years of experience w/ith the most difficult of chemicals applications can be used to solve your particular problems. Three aspects should, however, be mentioned briefly pumping explosive gas mixes, condensable vapors, and corrosive vapors and gases. 

This new IL also has negligible vapor pressure at ambient conditions. No reduction of mass has been observed under vacuum rotary evaporation at 100°C. The miscibilihes of this IL with a number of organic solvents (e.g., acetonitrile and acetone) are very good. However, it is immiscible with aqueous solutions. Accordingly, it can be uhlized as a potential new solvent for solvent extrachon of ionic species. Our preliminary experiments have shown that Cs can be quanhtahvely extracted to this new IL. 

To observe the transient spatiotemporal structure of the WP interference, we have performed the fs pump-fs probe experiment [37], The sample gas was prepared by molecular jet expansion of the mixture of iodine vapor and Ar buffer gas into a vacuum chamber. A continuous gas jet is preferable when we use a high-repetition-rate laser system. The estimated vibrational temperature was 170K[37]. 

By means of special experiments in vacuum, reversible photodesoption of oxygen under ultraviolet irradiation was shown [275]. Therefore the electric double layer on the polymer surface is modified. The increase of the emf obtained and the decrease in the dark conductivity and the photoconductivity with the action of water vapor confirms the proposed model [276],... 

The insulating action of the —CH2— group between the phenyl ring and the amino radical in benzylamine can be inferred from another group of experiments. It is well known that under vacuum u.v. irradiation of NH3 and the aliphatic amines the emission spectrum of the excited NH2 radical (a-band system) has been observed.26 Attempts in this laboratory to produce the same luminescent photodissociation in aniline vapor have so far failed. On the other hand, in benzylamine vapor the bands of the -NHj radical are easily observed on illumination by light in the vacuum u.v. range.31... 

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