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Infrared absorbing mirror

Light reflected from the infrared-absorbing mirror passes through specially designed optics which ensure uniform intensity across the entire DSC cell area. The computer-controlled shutter ensures precise sample exposure. The wavelength of the light beam is determined primarily by lamp selection, and can be refined by use of an operator-selectable bandpass filter. [Pg.409]

Similar principles can be used for designing selective absorbers, where the goal is absorb as much of the solar spectrum as possible and convert that absorbed energy into heat, or thermal energy. Conversely, reflective materials can be designed to select only visible (cold mirror) or infrared (hot mirrors) to isolate and direct selected portions of the solar spectrum for various applications. [Pg.34]

Dowling JP (1998) Mirror on the wall you re omnidirectional after all Science 282 1841-1842 Fabian J, Nakazumi H, Matsuoka M (1992) Near-infrared absorbing dyes. Chem Rev 92 1197-1226... [Pg.283]

Early bolometers used, as thermometers, thermopiles, based on the thermoelectric effect (see Section 9.4) or Golay cells in which the heat absorbed in a thin metal film is transferred to a small volume of gas the resulting pressure increase moves a mirror in an optical amplifier. A historical review of the development of radiation detectors until 1994 can be found in ref. [59,60], The modern history of infrared bolometers starts with the introduction of the carbon resistor, as both bolometer sensor and absorber, by Boyle and Rogers [12], The device had a number of advantages over the Golay cell such as low cost, simplicity and relatively low heat capacity at low temperatures. [Pg.336]

In the diffuse reflectance mode, samples can be measured as loose powders, with the advantages that not only is the tedious preparation of wafers unnecessary but also diffusion limitations associated with tightly pressed samples are avoided. Diffuse reflectance is also the indicated technique for strongly scattering or absorbing particles. The often-used acronyms DRIFT or DRIFTS stand for diffuse reflectance infrared Fourier transform spectroscopy. The diffusely scattered radiation is collected by an ellipsoidal mirror and focussed on the detector. The infrared absorption spectrum is described the Kubelka-Munk function ... [Pg.224]

Cold mirror A reflector that is coated by a dichroic material that absorbs or passes wavelengths in the infrared region while reflecting those in the UV range. [Pg.252]

Consider next the water molecule. As we have seen, it has a dipole moment, so we expect at least one IR-active mode. We have also seen that it has CIt, symmetry, and we may use this fact to help sort out the vibrational modes. Each normal mode of iibratbn wiff form a basis for an irreducible representation of the point group of the molecule.13 A vibration will be infrared active if its normal mode belongs to one of the irreducible representation corresponding to the x, y and z vectors. The C2 character table lists four irreducible representations A, Ait Bx, and B2. If we examine the three normal vibrational modes for HzO, we see that both the symmetrical stretch and the bending mode are symmetrical not only with respect to tbe C2 axis, but also with respect to the mirror planes (Fig. 3.21). They therefore have A, symmetry and since z transforms as A, they are fR active. The third mode is not symmetrical with respect to the C2 axis, nor is it symmetrical with respect to the ojxz) plane, so it has B2 symmetry. Because y transforms as Bt, this mode is also (R active. The three vibrations absorb at 3652 cm-1, 1545 cm-1, and 3756 cm-, respectively. [Pg.45]

The STG was cast from alx 10 3 M solution into which the mirror had been immersed for from 10 to 20 min (see Appendix 1). The presence of a monolayer was confirmed by ellipsometry (18 A). The spectral data agreed with data gathered on a similar system in a powder form. In this case, CuzO powder was immersed in a 0.01 M solution of isooctyl thioglycolate (OTG) in isopropanol for from 1 to 10 min, washed with pure isopropanol, dried in air, and analyzed via infrared transmission in a KBr dispersion pellet (see Appendix 2). A similar spectral shift of approximately 15 cm 1 (1739— 1724 cm-1) was observed and the lack of two distinct carbonyl absorbances suggested the formation of a monolayer. In both cases, the formation of a copper-mercaptoester salt may be responsible... [Pg.60]

Fundamental studies by reflection angle infrared spectroscopy of the bonding of EME coupling agents to metal oxides reveal a significant shift in the carbonyl absorbance band when the coupling agent is applied as a very thin layer on a metal oxide. The shift is reproducible and the extent varies with the type of oxide. These results were obtained both by use of copper mirrors and from CuzO powder coated with very thin layers of model compounds. The compounds were not removable by isopropanol, a solvent for the bulk compound. The thiol absorbances of thin layers of model compounds were also found to decrease in relative intensity with time. This illustrates that a specific chemical interaction has occurred. [Pg.63]

Remote multicomponent air samples can be drawn into a centrally located analyzer (under computer control) and then into the gas cell of an infrared spectrometer. Within the spectrometer, a system of lenses and mirrors passes an infrared beam in a predetermined path through the sample. The amount of energy absorbed by the sample is compared against a standard beam, and the difference is related to the concentration of the gas of interest. By changing the wavelength of the infrared beam, additional materials may be checked for in the gas sample and their concentration levels determined the same way. If the concentration of the compound of interest exceeds a predetermined level, an alarm is activated. [Pg.122]

An infrared spectrometer measures the frequencies of infrared light absorbed by a compound. In a simple infrared spectrometer (Figure 12-4), two beams of light are used. The sample beam passes through the sample cell, while the reference beam passes through a reference cell that contains only the solvent. A rotating mirror alternately allows light from each of the two beams to enter the monochromator. [Pg.519]

Thermal gravimetric analysis of the t-BOC protected copolymers shows a precipitous loss of 25% of the sample mass between 150 and 180 C then a plateau followed by slow decomposition above 300°C (Figure 4). These results mirror the DSC results. The first weight loss agrees well with that calculated for loss of CO2 and isobutene (25.4%) and occurs coincident with loss of the 1755 crrr carbonate absorbance in the infrared and the appearance of the broad phenolic OH absorbance (Figure 5). [Pg.202]


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