Ultra violet system

Radiation cure system. Other addition reaction cure systems that have emerged in recent years are the ultra-violet (UV) and electron beam (EB) radiation cure systems. The development of these systems has been prompted by the ever-increasing need for fast cure rates and low cure temperatures. The U V cure system... 

Tetrahydroalstonine gives with the Adamkiewicz test, as modified by Harvey et al., a colour similar to that given by yohimbine, which is taken to indicate the presence of a tetrahydro-/3-carboline ring system. Further, the ultra-violet absorption curves for yohimbine and tetrahydroalstonine... 

Unsaturated polyester finishes of this type do not need to be stoved to effect crosslinking, but will cure at room temperature once a suitable peroxide initiator cobalt salt activator are added. The system then has a finite pot life and needs to be applied soon after mixing. Such a system is an example of a two-pack system. That is the finish is supplied in two packages to be mixed shortly before use, with obvious limitations. However, polymerisation can also be induced by ultra violet radiation or electron beam exposure when polymerisation occurs almost instantaneously. These techniques are used widely in packaging, particularly cans, for which many other unsaturated polymers, such as unsaturated acrylic resins have been devised. 

The reactants are then mixed in various proportions, and the sedimentation ratio (scompiex/smucin)—the ratio of the sedimentation coefficient of the complex to that of the pure mucin itself—is used as the measure for mucoad-hesion. The ultra-violet absorption optics on the XL-A or XL-1 ultracentrifuge have been used as the main optical detection system. Although the polysaccharide is generally invisible in the near UV ( 280 nm), at the concentrations normally employed the mucin—in uncomplexed and complexed form—is detectable. 

In table 2 are listed the various band systems with the origin (ve) of each, from which are derived the energy levels of table 1. In general, the value of ve is merely the frequency of the first line of the Q branch, but the error thus introduced is negligible. Richardson s recent conclusions are based entirely on the identification of the lower level of his A and B bands with Dieke and Hopfield s B level (215). The agreement is very striking. Thus the vibrational level intervals, as measured by Richardson are 1313.26, 1276.42 and 1247.67 cm.-1, while the same intervals, as measured by Dieke and Hopfield,6 from the ultra-violet absorption bands, are 1313, 1276 and 1247 cm.-1... 

Any appropriate spectrophotometer capable for measuring both in the ultra-violet (UV) and visible range of the spectrum must essentially consist of an optical system that should produce monochromatic light in the range 190-780 nm and a suitable device for measuring the extinction (E) precisely and accurately. 

S. O Keeffe, C. Eitzpatrick, E. Lewis, An optical fibre based ultra violet and visible absorption spectroscopy system for ozone concentration monitoring. Sens. Actuators B, 125, 372-378 (2007). 

Light source. The most suitable light system examined was a Chromato-Vue Model C-3 from Ultra Violet Products, Inc., San Gabriel, CA. The light source was a GE G15T8, 15-W, Germicidal, 2537 bulb. The mercury lamp emitted radiation maxima at 254, 265, 280, 302, 313, 365, 405, and 436 nm. Radiation from this source passed... 

The ultra-violet light induces electromagnetic excitation in molecules absorbing the laser energy, and by subsequently applying the principle of absorption spectroscopy, kinetic and spectroscopic information relating to the electronically excited states of various energetic molecules have been derived. The systems studied to-date include s-TNB, s-TNT, triphenyl-amine, and mono- as well as di-nitronaphthalenes (Ref 13, 14, 20, 21 28)... 

G. G. Jones and Miles [136] examined the ultra-violet absorption spectra of nitrocelluloses having a range of nitrogen contents from 10.9 to 14.1%. The absorption curve shows a maximum close to 220 ny, and an inflection below 300 my. The extinction is relatively small (e = 15.0). This is typical of aliphatic compounds which lack a conjugated double bond system and give only the R spectrum. 

A more detailed overview of the main components of the GEOS-DAS system the forecast model, the input data (total ozone observations from Total Ozone Mapping Spectrometer /TOMS/ and vertical ozone profiles from the Solar Backscatter Ultra Violet instrument /SBUV/, the analysis scheme and its implementation could be easy found in the paper of Riishojgard [19]. 

There are numerous properties of materials which can be used as measures of composition, e.g. preferential adsorption of components (as in chromatography), absorption of electromagnetic waves (infra-red, ultra-violet, etc.), refractive index, pH, density, etc. In many cases, however, the property will not give a unique result if there are more than two components, e.g. there may be a number of different compositions of a particular ternary liquid mixture which will have the same refractive index or will exhibit the same infra-red radiation absorption characteristics. Other difficulties can make a particular physical property unsuitable as a measure of composition for a particular system, e.g. the dielectric constant cannot be used if water is present as the dielectric constant of water is very much greater than that of most other liquids. Instruments containing optical systems (e.g. refractometers) and/or electromechanical feedback systems (e.g. some infra-red analysers) can be sensitive to mechanical vibration. In cases where it is not practicable to measure composition directly, then indirect or inferential means of obtaining a measurement which itself is a function of composition may be employed (e.g. the use of boiling temperature in a distillation column as a measure of the liquid composition—see Section 7.3.1). 

J Slobodnik, AJH Louter, JJ Vreuls, I Liska, UAT Brinkman. Monitoring of organic micropollutants in surface water by automated online trace-enrichment-liquid-and-gas-chromatographic systems with ultra-violet diode-array and mass-spectrometry detection. J Chromatogr A 768 239-258, 1997. 

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