Mechanisms shutter

The first clinical IRET used thermopile sensors to achieve non-contact temperature measurement in the ear. In 1991 a tympanic thermometer for home use was first introduced to the consumer market (Thermoscan HM 1). It utilized a pyroelectric sensor which requires the use of a suitable mechanical shutter or chopper mechanism, since it is only sensitive to temperature changes [3]. The main advantage of the pyroelectric sensor unit was its lower cost. However, prices for thermo-... 

The other way to perform time-resolved measurements using IPs is to exchange IPs rapidly and successively in combination with a mechanical shutter. This method is valid for the measurements in which a time-resolution is of the order of a sub-second or longer. 

Fig. 17. A rear view of the rapid exchanger for imaging plates. The size of the IPs is 126x 126 mm (5" X 5"). A minimum exposure time for each IP is designed to be 0.1 s and a dead time between exposures is 0.2 s. Thus, the system allows 3.3 exposures per second. The controller (not shown here) synchronizes the motion of IPs with that of the mechanical shutter (not shown here) placed in front of specimens...

His experiments were primarily upon a single soda-lime silicate, which was chosen because it had been studied extensively in the literature and can be made in small amounts with fair optical quality. The decay for this glass with 0.8 per cent Nd203 added is shown in Fig. 33. It is quite clearly not a single exponential. One finds that the slope changes by a factor of three over the range examined and that the curvature increases with neodymium concentration. The measurements made at long times were done with a mechanical shutter that shielded the photomultiplier tube from the initial intense fluorescence. When this was not done, hysteresis in the photomultiplier tube led to spurious results. 

An oxygen sensor array using these principles was developed by Liebsch et al. [60]. A modification of the applied imaging set up is illustrated in Fig. 7. It consists of a CCD camera with a fast mechanical shutter, an array of 96 pulsed LEDs, a computer-steered pulse generator, a constant power supply, a light-guiding adapter with 96 optical fibers, and the corresponding excitation and emission filters. 

To measure all these spectra in the same condition, spectra for each delay time were recorded quasi-simultaneously. Ihe controller of the detector, the pulse generator and mechanical shutter were connected and managed by a personal computer. One specmim was accumulated for 8 sec. in one of the conditions and stored in the memory of the computer. Then the conditions were changed one after the other, and in each case it accumulate the spectra for 8 sec., which were recorded into the corres X>nding memories. After measuring all these conditions, it went back to the first condition and repeated this sequence again, where each spectrum was added onto the corresponding spectrum on the memories. In all it repeated this procedure for 500 times, which was equal to about 12 h for whole accumulation time and to al t 70 mins, for each spectrum. 

It was found that the VUV probe beam itself produced appreciable 0( Pj=2,i,o) atom LIF signals via the photolysis of O2 and NO2/SO2, respectively. In order to subtract these background 0( Pj 2,i,o) atoms from the 0( Pj=2,i,o) atoms produced in the H -h O2 reaction and in the 248/193 nm photolysis of NO2/SO2, respectively, an electronically controlled mechanical shutter was inserted into the photolysis beam path (see... 

Some degree of temporal resolution of emission may be obtained by incorporating a phosphoroscope attachment in the simple apparatus described above. A mechanical or electronic device is used to allow periodic and out-of-phase excitation and detection of luminescence. In the simplest case a mechanical shutter interrupts the excitation beam periodically and the detection system is gated so that emission is observed only after a fixed interval of time has elapsed after excitation. Under these conditions short-lived processes such as prompt fluorescence will have decayed to zero intensity and only longer-lived emission will be recorded. For mechanical devices the limit of measurable lifetime is of the order of 1 ms, thus allowing time resolved studies to be made of certain phosphorescence and delayed emission procesres (see ... 

To make such an instrument direct reading in percent transmittance, two preliminary adjustments are made the 0% T, or dark current, aUjuAiniem, and the 100% Tadjustment. The 0% Tadjustment is made wilh the detector screened from the source by clo.sing the mechanical shutter. Any small dark current in the detector is nulled electrically until the needle of the detector reads zero. 

Fig. 3. Block diagram of an ODMR spectrometer with PDMR and FDMR capability. The excitation and emission paths are at a 90° angle. S, F, and L are mechanical shutters, glass filters, and collimating lenses, respectively. A microwave amplifier may be placed between the microwave source and the low-pass filter the purpose of the latter is to eliminate harmonics. V is a He pressure-regulated valve for maintaining the sample at a fixed temperature between the minimum and 4.2 K. V2 is a large throughput valve for obtaining the minimum He temperature. A rotating sector often is placed around the tail section of the Dewar flask to eliminate fluorescence in PDMR measurements. [From L. E. Bums, Doctoral Dissertation, University of California, Davis (1992), with permission.]...

In this experiment, the photocurrent (/ph) of the sample is measured versus time (chronoamperometry) with or without an applied bias. In this case, monochromatic light is used over the solar UV-VIS-NIR spectrum (300-1100 nm). Figure 7.1 shows the experimental setup, which consists of an illumination source with a monochromator and a set of filters for order sorting. A mechanical shutter to chop... 

In 1994, ferroelectric shutters (FLC) were introduced as an alternative to mechanical shutters [11]. FLC devices are polarization based shutters that can be switched in about 50 ps. Using two shutters simultaneously prompt autofiuorescence was effectively suppressed by a factor of 10. FLC shutters have poor transmission for UV light and were therefore only used at the emission side. Also, the switching time of 50 ps allows detection of relatively long-lived luminescence only. 

Fluorimeters which use a continuous fight source can usually be adapted for phosphorescence work by addition of a phosphorimeter attachment, which is usually either a pair of mechanical shutters on the excitation and emission... 

The Photo Processing System (Platform No. 4) consists of (1) a large surface high power monochromic UV lamp (wavelength = 365 nm and power = 100 mW/cm ) with a mechanical shutter activated by an electrical pulse and an AC stabilized power supply, (2) a cell support and (3) probes and controllers for control and data acquisition during the drop experiment. 

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