Thin films apparatus

T iquid films, whether in the form of natural falling films or in the more advanced form of mechanically agitated films in thin-film apparatus, offer convenient conditions for the solution of many difficult processing problems because of the films favorable surface-to-volume ratio and good heat transfer. This is especially so with an agitated film between heating wall and film. The agitated-film principle has previously found its broadest application in thin-film evaporators. 

The favorable working conditions of the thin-film evaporator enabled the equally successful application of the thin-film principle for fractionation (5), absorption, chemical reactions (6), and drying (7, 8). In these processes and applications, the thin-film apparatus is used mainly to treat heat sensitive and lower-viscosity products that flow on the influence of gravity alone. This particular type of apparatus in a special design can also be used to process highly viscous products to... 

Assuming the gap s between rotor blade and heating wall is not enlarged, the rotor of the thin-film apparatus for processing liquids of... 

Figure 2. Comparison between mean film thickness of falling and agitated films in a thin-film apparatus, expressed as a function of peripheral load and viscosity. Curves I, 2, and 3, falling film according to Equation 1 curve 1° and 2°, agitated film in the thin-film apparatus...

Figure 4. Influence of different rotor designs A and B in thin-film apparatus on the mean thickness, expressed as a function of rotor speed and viscosity...

The infrared spectra of pyridinyls are measured conveniently with the thin film spectroscopy apparatus and the changes which ensue on dimerization have been examined. A complete inO red spectrum for 4 at 77 K has been reported External sapphire windows on the thin film apparatus allow spectra to be measured... 

The size of the display is limited only by the size of the thin-film apparatus used to make the film. A large number of organic materials have been examined for this application. Most of the successful ones are those based upon the modification of the basic backbone of those compounds given in... 

The author s thin-film apparatus, as developed further by VEB Glaswerk Stiitzer-bach and illustrated in Fig. 196, was adapted from the early types of molecular stills operating with a falling film. It contains two concentric tubes. The inner tube, which is interchangeable by the provision of a ground joint, can be heated by an element a and functions as a surface for evaporation. The outer tube acts as condensing surface. 

The methods of steam distillation have been summarized by Bernhauer [13] and Thormann [14]. A detailed discussion of practical and theoretical aspects of steam distillation as illustrated by the distillation of essential oils is given by von Weber [15], Rigamonti [16] developed a nomogram which can be used to calculate the steam requirements for various enrichments. Prenosil [16a] compared theoretical and experimental steam distillation data for multicomponent mixtures. He modified the calculating method by introducing a value for evaporation efficiency. Steam distillation can also be carried out in thin-film apparatus. Berkes etal. [16 b] give a description of the material transfer conditions of a steam distillation performed in such apparatus in terms of the balance equations. 

A2.1.1 Thin-Film Apparatus, made of heat-resistant glass and stainless steel, conforming to the dimensions given in Fig. A2.1. A suggested assembly is shown in Hg. A2.2. 

MOKE measurements can be made using relatively simple and inexpensive apparatus, compared to most other surface magnedc probes and surface analytical techniques. MOKE is usefid for the mj netic characterizadon of films of one to several monolayers, thin films, or the near-surface regions of bulk materials. MOKE has... 

Wipe the potash solution from the outside and inside of the inlet tube of the apparatus with filter paper. Smear a thin film of vaseline on the ground end of the soda-lime tube before replacing it, and fit to the open ends of the apparatus, stoppers of rubber and glass rod, which are not removed, except when the apparatus is in use. As the potash apparatus has jto be... 

CVD, the other major deposition process, is used on a large scale. A typical low-E glass is obtained by depositing a thin film of silicon dioxide followed by another thin film of fluorine-doped tin oxide. The Si02 acts as a diffusion barrier and the Sn02 reduces the emissivity. A typical CVD apparatus is shown in Fig. 

The statics and dynamics of microstructures are governed by the forces that create or maintain them. Rarely can the forces be measured directly. But forces between special surfaces immersed in fluid can now be accurately gauged at separations down to 0.1 nm with the direct force measurement apparatus, an ingenious combination of a differential spring, a piezoelectric crystal, an interferometer, and crossed cyhndrical surfaces covered by atomically smooth layers of cleaved mica (Figure 9.4). This recent development is finding more and more applications in research on liquid and semiliquid microstructures, thin films, and adsorbed layers. 

The microscale friction and wear behavior of thin film of gold (Au) which was prepared in a vacuum sputtering apparatus was investigated. The substrate is Si(lOO) wafer. The film thickness is about 800 nm. For comparison, the microscale friction and wear of the substrate was also studied. 

The surface forces apparatus (SEA) can measure the interaction forces between two surfaces through a liquid [10,11]. The SEA consists of two curved, molecularly smooth mica surfaces made from sheets with a thickness of a few micrometers. These sheets are glued to quartz cylindrical lenses ( 10-mm radius of curvature) and mounted with then-axes perpendicular to each other. The distance is measured by a Fabry-Perot optical technique using multiple beam interference fringes. The distance resolution is 1-2 A and the force sensitivity is about 10 nN. With the SEA many fundamental interactions between surfaces in aqueous solutions and nonaqueous liquids have been identified and quantified. These include the van der Waals and electrostatic double-layer forces, oscillatory forces, repulsive hydration forces, attractive hydrophobic forces, steric interactions involving polymeric systems, and capillary and adhesion forces. Although cleaved mica is the most commonly used substrate material in the SEA, it can also be coated with thin films of materials with different chemical and physical properties [12]. 

Nicolau, Y. F. 1986. Method and apparatus for deposition on a substrate of a thin film containing cationic and anionic constituents. French Patent No. 2569427. 

Figure 2. Schematic representation of the experimental apparatus used for measurement of the 7t-A curves of a thin film of PhDA2-8 molecules at the air/water interface.

Thin-film balance apparatus, 12 7 Thin-film composite membranes, 21 633 Thin-film deposition, laser ablation for, 24 740... 

Now fit the calcium chloride tube closely to the constricted part of the combustion tube and connect the sodium hydroxide-asbestos tube to the calcium chloride tube of the aspirator. Then remove the rubber stopper from the combustion tube, push back the stand carrying the drying apparatus so as to make more room, raise the copper block with the boat to the opening of the combustion tube, with the forceps insert the boat, push it inwards 4-5 cm. up to the furnace with a clean glass rod of suitable size, taking care not to tip the boat over, insert the rubber stopper loosely into the tube, moistening the stopper if necessary with a very thin film of glycerol,... 

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