Particle measurement sensors

The measurement of the cosmic microwave background. Far infrared astronomers were the first to develop thermal detectors. Some of the resulting technologies, such as neutron transmutation doping (NTD) [3], have been transferred to particle detection sensors and have allowed many groups (e.g., ref. [4-11] to make rapid progress). 

Nano in-situ sensor and LS-50 liquid sampler are designed for particle measurements in process chemicals and DI water. They are ideal for sampling main process supply lines or point-of-use delivery lines where continuous monitoring of contamination levels is necessary. They can be operated either in-line or batch mode. 

In case of ethanol, the sensitivity of the sensor to ethanol-contained air is about 1/S of that of methanol. Because the SA molecular sieve is designed for the separation of the molecular size of methanol, ethane and propane or smaller, the SA molecular sieve coated sensor gives much less sensitivity with ethanol contained air. Unlike other solid particle coated sensor, such as activated carbon sensor, the molecular sieve coated sensor has selectivity to the molecular size of detecting material. The outcome presented in Fig. 3 indicates that the sensor coated with SA molecular sieve satisfactorily discern methanol vapor from bigger molecules, but it does not separate from small molecules. When 4 A molecular sieve coated sensor is implemented to detect methanol, the same result of measuring ethanol with S A molecular sieve sensor is yielded as shown in Fig. 4. In other... 

The profiles shown in Figure 32 are typical for sand-water flows, where because of gravity, more particles are found near the bottom of the pipe. Solids concentrations were obtained from measuring sensor voltages such as those shown in Figure 32 and from the calibration curve. This calibration curve was obtained by using a least-squares fit of the experimental data of Figure 27. 

Figure 8 Frequency response of a particle pressure sensor to the gas pressure change, (a) Setup to test the dynamic response (b) gas pressure (measured by a pressure transducer) and the phase shift. (Campbell and Wang, 1990.) (With permission of Institute...

The standard calibration of the MicroCount 05 is based on uniform polystyrene beads traceable to NIST. This provides accurate sizing for a broad range of materials in the ranges above roughly lOpm. At smaUer sizes, the optical properties of the sample influence the sensor response significantly. Tliis is especially true for the smallest particles measured in the scattering channel. When calibrated with polystyrene, the sensor may be used as a comparison instrument. If additional applications information is available, a calibration curve specific to the material can be developed. 

In this work, two optical particle measurement systems, on the basis of Statistical Extinction Method, have been developed. The Statistical Extinction Sensor (SE-Sensor) determines a mean particle size and a particle concentration inline in particle processes. Eor this purpose, the temporal course of the transmission of a light beam through the particle collective is measured and the mean particle size and the concentration are determined according to the Statistical Extinction Method (SE-Method). The PSD-SE-Sensor measures the temporal course of the transmission of nine light beams with different beam cross sections and determines a particle size distribution and concentration according to an extended Statistical Extinction Method (PSD-SE-Method). 

Arbitrary the book can be divided into two complementary parts. The first one describes the physical and chemical basics leading to description of the method of semiconductor sensors. The mechanisms of underlying processes are given. These processes involve interaction of gas with the surface of semiconductor adsorbent which brings about tiie change of electric and physics characteristics of the latter. Various models of absorption-induced response of electric and physics characteristics of semiconductor adsorbent are considered. Results of numerous physical and chemical experiments carried out by the authors of this book and by other scientists underlying the method of semiconductor sensors are scrupulously discussed. The possibility of qualitative measurements of ultra-small concentrations of molecules, atoms, radicals as well as excited particles in gases, liquids and on surfaces of solids (adsorbents and catalysts) is demonstrated. 

Application of semiconductor sensors for measuring concentration of active particles in solids is of great interest for studies of peculiarities of the physical-chemical processes in real solids (for example, in polymers) involving free atoms and radicals. 

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