Transflectance liquid cell

Thermostatted transflectance liquid cell Transmission microcell Remote flberoptics assemblies Film holding cell... 

Baur, G, Wittwer, V Berreman, DW (1976). Determination of the tilt angles at surfaces of substrates in liquid crystal cells. Physics Letters A, Vol. 56, No. 2, (Mar), pp. 142-144. Chen, TJ Chu, KL (2008). Pretilt angle control for single-cell-gap transflective liquid crystal cells. Applied physics letters, Vol. 92, No. 9, (Mar), pp. 091102. 

Solid sample cup Rotating solid sample cup Liquid cup Viscous liquid cup Transmission liquid cell Disposable sample cup Transflectance cell Research transflectance cell Chemical cell... 

Several general factors should be weighed when designing or choosing a liquid cell. The mode of detection-transmission or transflectance will influence the decision. Other factors to consider are the... 

Calibrations for degrees Brix and acidity in fruit juices have been performed utilizing transflectance and a 45°C liquid cell [9]. The calibration parameters are presented in Table 22.2 to Table 22.4 with the wavelengths utilized for each calibration. 

Chigrtnov, VG, Kozenkov, VM Kwok, HS (July 22, 2008). Photoalignment of Liquid Crystalline Materials Physics and Applications, John Wiley Sons Ltd, ISBN 0470065397, West Sussex. Fan, YY, Chiang, HC, Ho, TY, Chen, YM, Hung, YC, Lin, IJ, Sheu, et al. (2004). A Single-Cell-Gap Transflective LCD. SID Symposium Digest of Technical Papers, Vol. 35, No. 1, (May), pp. 647-649. 

Transflectance is not likely to be more successful than transmittance for analysis of milk by NIR, because the surface presented to the instrument will be changing in composition, due to the progressive changes in fat content. Transmittance or reflectance of the sample in a large cell, with continuous agitation is the recommended method of sample presentation for NIR analysis of milk, or any other type of liquid sample containing suspended material that is liable to settling at the bottom or surface of the cell. 

Liquid NIRA differs from NIR applications for ground or powdered samples in a few key ways. Rather than utilizing tme reflectance measurements, liquid analysis involves transmission or a combination of transmission and reflectance sometimes referred to as transflectance [1]. Another way in which liquid measurement differs from the measurement of powders involves the introduction of the sample to the instrument. Preparation of a liquid sample may involve dilution, suspension, or homogenization prior to sample introduction. A different type of sample cell, usually a flow cell of some type, is then required. 

Another type of transflectance spectroscopy that is commonly used for measurements of near-infrared spectra falls somewhere between specular reflection and diffuse reflection spectroscopy (see Chapter 16). Because overtone and combination bands are weak, anomalous dispersion is usually negligibly small in the near infrared. It is quite common for the NIR spectra of liquids to be measured by transflection using the same optical geometry used for diffuse reflection. In this case, the sample is loaded in a cell whose rear face is a ceramic disk. Radiation that has passed through the sample is scattered back through the sample, emerges from the window, and is focused onto the detector. This is a particularly useful way of measuring the spectrum of turbid samples, such as milk. 

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