Peak spectral responsivity

Figure 4. The three-peaked spectral response of the human visual system, the peak...

The problem with Wald s assertion of a peak spectral response for the L-channel near 565-580 nm is in the protocol. This protocol has led others to the same awkward results. This protocol should not be relied upon in the light of the data, including that in the following section. 

Nonstationary power spectral density functions for the displacement response of a dam reservoir system subjected to a simple but nonstationary random acceleration excitation are obtained by a frequency domain approach due to Shinozuka. These spectral response solutions are new and are checked satisfactorily in the limiting stationary case and against the corresponding solution obtained previously by a time domain approach. For the range of frequency ratio Oj- representing dam reservoir interaction effect, it is found that the displacement spectral peak value increases with increasing dam flexibility. The location of the spectral peak is at a nearly constant value of f2Qj- (w/o) ) (c x/ s) 0.6, which means that the peak spectral response is at... 

Short-circuit current responsivity Open-circuit voltage responsivity Peak spectral responsivity. 

The PL spectrum and onset of the absorption spectrum of poly(2,5-dioctyloxy-para-phenylene vinylene) (DOO-PPV) are shown in Figure 7-8b. The PL spectrum exhibits several phonon replica at 1.8, 1.98, and 2.15 eV. The PL spectrum is not corrected for the system spectral response or self-absorption. These corrections would affect the relative intensities of the peaks, but not their positions. The highest energy peak is taken as the zero-phonon (0-0) transition and the two lower peaks correspond to one- and two-phonon transitions (1-0 and 2-0, respectively). The 2-0 transition is significantly broader than the 0-0 transition. This could be explained by the existence of several unresolved phonon modes which couple to electronic transitions. In this section we concentrate on films and dilute solutions of DOO-PPV, though similar measurements have been carried out on MEH-PPV [23]. Fresh DOO-PPV thin films were cast from chloroform solutions of 5% molar concentration onto quartz substrates the films were kept under constant vacuum. 

A photodetector with a suitable spectral response for the detection of the fluorescence emission. As mentioned above, the fluorescence of most Cr3+-activated materials consists of either the red R-lines or a broadband infrared emission with the peak wavelengths ranging from -750 to 1000 nm, or both emissions. Thus, the widely available, compact and inexpensive silicon PIN photodiodes are the most suitable photodetectors for these applications. In some particular circumstances, where high speed and high sensitivity of detection are required, a silicon-based avalanche diode could be the best alternative to the PIN photodiode, at small price premium ... 

The use of a linear detector array in the image plane of a polychromator in place of the fluorescence monochromator in Figure 12.1 enables the parallel data accumulation of complete fluorescence spectra. Silicon photodiode arrays, operated in a CCD mode(34) are the most widely used detector elements. The spectral response of the diodes enables fluorescence to be detected from the near-UV up to ca. 1100 nm with a peak response in the near-IR. Up to 8192 elements are now available commercially in a single linear array at low cost. However, the small length of each element (ca. 10 [im) presently limits sensitivity and hence cylindrical lens demagnification is often necessary. 

The resistivity of the films increased from 10 O-cm for very low Cd content to a maximum of ca. 10 U-cm at 6% Cd and then slowly dropped again with increasing Cd. This maximum correlates with the minimum crystal size, suggesting a dominant role of grain boundaries in the conduction mechanism. The spectral response of the photoconductivity blue-shifted with increase Cd content up to a peak response at 1.35 p,m for 8.4% Cd. 

Films were deposited from solntions of lead and tin salts (the salts used were not specified) with ammoninm acetate, ethylenediamine, and selenonrea at a pH > 9 (probably at least 11) [34]. To obtain thicker films, deposition was repeated a nnmber of times and the films were annealed therefore it is not known if solid so-Intion formation occnrred in as-deposited films. In annealed films, Pbi -j Snj Se solid solntions with x np to 0.11 were verified by XRD. The spectral response of the photoconductivity of the (annealed—as-deposited films were not photosensitive) films shifted from a peak at ca. 4 p,m (pure PbSe) to ca. 7.5 p,m (11% Sn), supporting solid solution formation of the annealed films. The room-temperature, dark resistance of the (probably annealed, but not certain) films varied from 1 to 300 kO, depending on deposition conditions. 

Figure 6 shows a typical chromatogram obtained from such a procedure. In this chromatogram, the elution of the thio-tetrazole, the R and S isomers of moxalactam, and the moxa-lactam decarboxylated product are shown. In this test for other related substances, only those substances which are not dealt with by specific tests are considered. Quantitative information is obtained by summing the response for all the extraneous peaks and comparing them to the sum of the response for the R and S isomers of a diluted moxalactam reference standard. The assumption is made that all of these materials have similar spectral response characteristics at 254 nm. 

As indicated in Section 5.4.5, it is not appropriate to consider the observed spectral absorption characteristic of a single chromophore as a single function and speak of the half-amplitude points as describing the waveform. The peak wavelength and the two half-amplitude points can be used for less critical work. However, the correct description of the waveform requires that the waveform on each side of the pseudo-peak be plotted as an exponential function and the wavelength specified at which this function is equal to 1/e of its peak value. These two 1/e values properly describe the measured spectral response. 

Figure 5.5.10-2 compares the typical putative spectrums based on such a linear analysis, (3, y, p compared to the actual chromophores, Rhodonines 5, 7 9 [with Rhodonine(l 1) shown for completeness. It is not significant in human vision except for aphakic patients.] Hunt describes the (3,y p spectrums as probable sensitivity curves of the three types of cones. He did not discuss any rod spectrum in his figure. The probable sensitivity curves appear to have been normalized individually. The peak in the p spectrum appears to be at a longer wavelength than frequently suggested. However, it is still at too short a wavelength to support the known spectral response of the human eye as illustrated by the Photopic Luminosity Function. 

Wolken s figure did not include any spectral response associated with the S-channel (alias blue channel) of vision. This spectral response has been included in the Table for completeness. The S-channel is clearly represented in Wald s papers149 at a peak wavelength as suggested here. 

Section. Figure 9 shows the wavelength region where the human eye responds, the spectral response of the eye, overlaying an Air Mass 1.5 global solar spectrum. The peak of this response is at 555 nm, corresponding to the color green. 

Fig. 15. Spectral response of thermopile pyranometer measuring total solar radiation is shown with thick black line. Spectral radiance (brightness) of the sky dome (blue line). The cut-off at 3000 nm means the radiometer will not respond to the infrared sky radiation that peaks at 7000...

A real-time spectral data monitor was placed in operation. The monitor consists of an independent microprocessor-based system that acquires real-time spectral data and additional housekeeping information flowing through the CAMAC/HP computer-interface lines. The complete laser-induced fluorescence spectrum produced by each laser shot is displayed in real time. The system also provides a two-channel output to an analog chart recorder that produces two profile traces (usually the laser-induced phycoerythrin and chlorophyll a spectral response peaks). 

The threshold curve is a plot of retention time versus a similarity factor threshold, below which the presence of an impurity cannot be distinguished from spectral noise. The threshold trace may be computed automatically from the standard deviation of a number of user-selected pure noise spectra. Alternatively, the threshold may be set at a fixed value. Similarity and threshold curves tend to rise at the extremities of the eluted peak, even when no impurity is present. As signal strength decreases, a larger proportion of the spectral response is caused by noise. If an impurity is present at a detectable concentration, the similarity curve will intersect the threshold (Fig. 5). 

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