Evaporation Techniques

Dryers. Drying, another type of evaporation technique, is suited for waste streams of very high soHds content. Several common types of dryers are vacuum rotary dryers, dmm dryers, tray and compartment dryers, and pneumatic conveying dryers. 

The retention gap techniques, essential for the analysis of very volatile components, are often replaced by concurrent eluent evaporation techniques, due to their simplicity and the possibility of transfering very large amount of solvent. In this case, the solvents are introduced into an uncoated inlet at temperatures at or above the solvent boiling point. 

The analysis of sterols, sterols esters, erythrodiol and uvaol, and other minor components of oils and fats, is usually carried out by normal-phase HPLC-HRGC by using a loop-type interface and the concurrent eluent evaporation technique, as reported in the papers cited by Mondello et al. (48) (up to 1995) and in more recent papers (49, 50). More recently, reversed-phase LC-GC methods have been... 

An on-line supercritical fluid chromatography-capillary gas chromatography (SFC-GC) technique has been demonstrated for the direct transfer of SFC fractions from a packed column SFC system to a GC system. This technique has been applied in the analysis of industrial samples such as aviation fuel (24). This type of coupled technique is sometimes more advantageous than the traditional LC-GC coupled technique since SFC is compatible with GC, because most supercritical fluids decompress into gases at GC conditions and are not detected by flame-ionization detection. The use of solvent evaporation techniques are not necessary. SFC, in the same way as LC, can be used to preseparate a sample into classes of compounds where the individual components can then be analyzed and quantified by GC. The supercritical fluid sample effluent is decompressed through a restrictor directly into a capillary GC injection port. In addition, this technique allows selective or multi-step heart-cutting of various sample peaks as they elute from the supercritical fluid... 

Another evaporation technique is molecular beam epitaxy (MBE). MBE produces extremely pure and very thin films with abrupt composition changes and is being considered for extremely exacting electronic and optoelectronic applications. PI However, the deposition rate is very slow and the process is still considered experimental. 

The iron complex Fe[P(OC8H5)3]2[(CgH40)P(OC6H5)2]2 has been synthesized by metal-atom evaporation-techniques (190). The complex is, formally, the result of two ortho-oxidative, C-H additions, accompanied by loss of a molecule of H2. 

To remove any metallic Au, the reaction mixture is evaporated to dryness and subsequently passed over a commercial terra infusorii column in a minimal volume of solvent. Crystallization may be performed by slow diffusion of a two-layer system. Yields are low (10-60%). The metal evaporation technique (see 8.2.1.2) gives higher yields than the sodium borohydride method. 

Alivisatos and coworkers reported on the realization of an electrode structure scaled down to the level of a single Au nanocluster [24]. They combined optical lithography and angle evaporation techniques (see previous discussion of SET-device fabrication) to define a narrow gap of a few nanometers between two Au leads on a Si substrate. The Au leads were functionalized with hexane-1,6-dithiol, which binds linearly to the Au surface. 5.8 nm Au nanoclusters were immobilized from solution between the leads via the free dithiol end, which faces the solution. Slight current steps in the I U) characteristic at 77K were reflected by the resulting device (see Figure 8). By curve fitting to classical Coulomb blockade models, the resistances are 32 MQ and 2 G 2, respectively, and the junction... 

Explosive decomposition occurs on heating from 130 to 150°C [1]. When heated above 160°C, explosive rearrangement occurs with an exotherm to 300°C. An explosion occurred during fractional distillation at 108-110°C/20 mbar. It may be distilled without explosion by a flash evaporation technique [2,3],... 

The solvent evaporation technique is based on the use of organic solvents as dissolving agents for the lipid matrix (i.e., phospholipids or triglycerides and monoglycerides) and the subsequent evaporation of the solvent within an aqueous medium until a CLS dispersion is obtained. 

Fig. 3 Preparation of polymeric nanoparticles by emulsion solvent evaporation technique...

O Donnell PB, McGinity JW (1997) Preparation of microspheres by the solvent evaporation technique. Adv Drug Deliv Rev 28 25-42... 

SMOLEDs contain small-molecule emissive materials that can be processed by either vacuum deposition (evaporative) techniques or solution coating. The emissive small molecule may be a fluorescent (singlet excited state) or a phosphorescent (triplet excited state) emitter. 

The NSOM tip is obtained by heating and pulling a single-mode optical fiber down to a fine point. A reflective metal coating (aluminum, silver or gold) is deposited by vacuum evaporative techniques in order to prevent light from escaping. 

Synthesis of nano-structured alloys by the inert gas evaporation technique A precursor material, either a single metal or a compound, is evaporated at low temperature, producing atom clusters through homogeneous condensation via collisions with gas atoms in the proximity of a cold collection surface. To avoid cluster coalescence, the clusters are removed from the deposition region by natural gas convection or forced gas flow. A similar technique is sputtering (ejection of atoms or clusters by an accelerated focused beam of an inert gas, see 6.9.3). 

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