INDEX basic principles

The goal of the polychromatic LGS (PEGS) is to provide us with a 100% sky coverage, down to visible wavelengths. Its basic principle relies on the chromatic property of the air refraction index n (Fig. 18). 

In Sect. 15.2 we concluded that refractive index variation in the aqueous cover media shifts the effective refractive index of the waveguide modes. Thus, by monitoring on-line the effective refractive index, the refractive index change can be followed. This is the basic principle of waveguide sensing. 

The basic principle underlying the LLNA is that sensitizers induce a primary proliferation of lymphocytes in the lymph node draining the site of chemical application. This proliferation is proportional to the dose applied and to the potency of the allergen, and provides a measurement of sensitization. The LLNA assesses this proliferation as a dose-response in which the proliferation in test groups is compared to that in vehicle treated controls. The ratio of the proliferation in treated groups to that in vehicular controls, termed the Stimulation Index , is determined, and must be at least three before a test substance can be further evaluated as a potential skin sensitizer. The test substance, plus vehicle and positive control, is applied for three consecutive days to the ears of test mice, on days 4 and 5 the animals are left alone, and on the 6th day they are prepared for the proliferation assay, sacrificed, and the measurements are done. 

The best way of finding the entry for a particular compound in the Beilstein Handbook is to identify in which volume the compound is listed, and then to consult the appropriate volume index. In order to identify the volume of interest a few basic principles of the Beilstein System need to be understood and these are described below. 

Figure 8b shows the basic principle and the light path of the refractometer, where 0, 0", 0 ", and the cuvette are drawn enlarged to make the details clear. If both the compartments are filled with a solvent (i.e. n=n0),the illuminated pinhole will be imaged at point O. However, if the solvent in one of the compartments is replaced by a dilute polymer solution with a slightly different refractive index (i.e. n=no+An), the light will be bent first by the glass plate, then by the... 

The interaction phenomenon of the analyte with radiation is governed or modifies the principle on which light is transmitted through the waveguide. Depending on that interaction, we can differentiate three basic types of intrinsic optical sensors [82] refractive-index-type sensors, luminescence-based sensors and absorption-type sensors. 

A chemical sensor is a device that transforms chemical information into an analytically useful signal. Chemical sensors contain two basic functional units a receptor part and a transducer part. The receptor part is usually a sensitive layer, therefore a well founded knowledge about the mechanism of interaction of the analytes of interest and the selected sensitive layer has to be achieved. Various optical methods have been exploited in chemical sensors to transform the spectral information into useful signals which can be interpreted as chemical information about the analytes [1]. These are either reflectometric or refractometric methods. Optical sensors based on reflectometry are reflectometric interference spectroscopy (RIfS) [2] and ellipsometry [3,4], Evanescent field techniques, which are sensitive to changes in the refractive index, open a wide variety of optical detection principles [5] such as surface plasmon resonance spectroscopy (SPR) [6—8], Mach-Zehnder interferometer [9], Young interferometer [10], grating coupler [11] or resonant mirror [12] devices. All these optical... 

OPTICAL RESONANCE AND TWO-LEVEL ATOMS, L. Alien and J.H. Eberly. Clear, comprehensive introduction to basic principles behind all quantum optical resonance phenomena. 53 illustrations. Preface. Index. 256pp. 5)4 x 8H. 

Though a search dealing with an organic compound may start with the formula index of Chemical Abstracts, while one on an industrial engineering problem may begin in the Engineering Societies Library in New York City, the same basic principle of searching is involved—namely, key terms are looked up in the most appropriate sources. 

This text is a comprehensive collection of concise and readable explanations of basic principles in toxicology and the potential hazards of chemicals. It contains more than 1000 entries, including entries related to research and clinical toxicology, risk assessment, ecotoxicology, epidemiology, radiation, noise, information resources, organizations, and education. As with the 1st edition, this volume is extensively cross-referenced, contains a detailed index, and provides numerous references to primary and secondary literature. 

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