Near-Infrared Sources

On the other hand, imique physical properties and potential applications of nanoscaled lanthanide-doped LaFa have been discussed in many reports. For instance, van Veggel et al. reported the bright white light through up-conversion of a single near-infrared source by thin film of LaFaiYb, Eu /Er /Tm NPs (Figure 65) (Sivakumar et al., 2005). And the silica films with (Er +, Nd +, and Ho ) doped LaFs NPs possessed the visible white luminescence (Sudarsan et al., 2005). 

N. C. Abbot et al., Laser Doppler Perfusion Imaging of Skin Blood Flow Using Red and Near-Infrared Sources, J. Invest. Dermatol., 107(6), 2235 (1996). 

The results described above all refer to Raman measurements made prior to the introduction of FT methods and near-infrared sources. More recent work shows that anisotropic measurements are far easier than they were, and can be made at room temp>erature on heated or cooled specimens with consummate ease. The measurements on highly oriented polyethylene shown in Figure 7.7 are simple to produce both at room temperature and at — 180°C. An analysis is available [16]. 

Any infrared heat lamp or any near-infrared source where a strong visual stimulus is absent (luminance of less than E-06cd/cm ). 

Figure 6.1. Spectral energy density of blackbody sources at 1500, 2000, 2500, and 3000°C. The temperature of many sources used for mid-infrared spectrometry is 1500°C, while the temperature of many near-infrared sources is 3000°C.

Continuous wave (CW) lasers such as Ar and He-Ne are employed in conmionplace Raman spectrometers. However laser sources for Raman spectroscopy now extend from the edge of the vacuum UV to the near infrared. Lasers serve as an energetic source which at the same hme can be highly monochromatic, thus effectively supplying the single excitation frequency, v. The beams have a small diameter which may be... 

Photometric Moisture Analysis TTis analyzer reqiiires a light source, a filter wheel rotated by a synchronous motor, a sample cell, a detector to measure the light transmitted, and associated electronics. Water has two absorption bands in the near infrared region at 1400 and 1900 nm. This analyzer can measure moisture in liquid or gaseous samples at levels from 5 ppm up to 100 percent, depending on other chemical species in the sample. Response time is less than 1 s, and samples can be run up to 300°C and 400 psig. 

One can measure the tip and tilt with a natural guide star for these only modes. Figure 13 shows that the magnitude of the tilt reference star has to be brighter than typically 15 in the near infrared. The sky coverage is limited by the probability to find that star within the isoplanatic patch of the programme source. 

Recently, SETA BioMedicals has developed a new near-infrared squaraine-based label Seta-633, which can be used to study the interaction between low-molecular-weight analytes and proteins using fluorescence lifetime as the readout parameter [19]. This label exhibits lower quantum yields and shorter fluorescence lifetimes when free in solution, but these values substantially increase upon interaction with proteins, which is contrary to tracers like Cy5 or Alexa 647. It was demonstrated in a model assay that a biotinylated Seta-633 binds to anti-biotin with high specificity. Importantly, the lifetime of Seta-633-biotin increases about 2.76 fold upon binding to a specific antibody (anti-biotin, MW =160 kDa), while the titration with BSA or nonspecific antibody does not result in a noticeable change in lifetime (Fig. 13). The label is compatible with readily available light sources (635 nm or 640 nm lasers) and filter sets (as for Cy5 or Alexa 647) and its... 

Thus, the region 2100-1830 cm 1 can be covered. This allows us to monitor CO(v,J) by resonance absorption and various M(CO)n [n = 3-6] as a result of near coincidences between the CO laser lines and the carbonyl stretching vibrations of these species. The temporal response of the detection system is ca. 100 ns and is limited by the risetime of the InSb detector. Detection limits are approximately 10 5 torr for CO and M(CO)n. The principal limitation of our instrumentation is associated with the use of a molecular, gas discharge laser as an infrared source. The CO laser is line tuneable laser lines have widths of ca. lO cm 1 and are spaced 3-4 cm 1 apart. Thus, spectra can only be recorded point-by-point, with an effective resolution of ca. 4 cm 1. As a result, band maxima (e.g. in the carbonyl stretching... 

There are, however, many approaches to DNA sequencing, and even some recent instruments such as the sequencer made by LI-COR [28] do not use a CCD. The latter uses instead a very-low-noise silicon avalanche photodetector to excite near infrared-emitting dyes. The source is a laser diode emitting at 785 nm. It is a compact system that can be mounted on a focusing stage with confocal optics and it is meant for small laboratories that do not have HTS requirements. 

Miniaturized chemical analysis systems have been developed for most macroscopic counterparts (Dittrich et al. 2006). The availability of optical fibers, light sources, and detectors in the visible UV and near-infrared (NIR) wavelengths makes it possible to integrate spectroscopic measurements in microreactors (Lobbecke et al. 2005). Fourier transform infrared spectroscopy (FTIR) is an efficient, broadly applicable... 

In short, near-infrared spectra arise from the same source as mid-range (or normal ) infrared spectroscopy vibrations, stretches, and rotations of atoms about a chemical bond. In a classical model of the vibrations between two atoms, Hooke s Law was used to provide a basis for the math. This equation gave the lowest or base energies that arise from a harmonic (diatomic) oscillator, namely ... 

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