Containment lenses

FIGURE 1.4 Schematic of a triple quadrupole/LIT mass spectrometer modified by superposing an auxiliary RF on IQ2 and IQ3 containment lenses. (Note the pulsed dual ESI source is also illustrated.) (Reproduced from Xia, Y. Liang, X.R. McLuckey, S.A., J. Am. Soc. Mass Spectrom. 2005,16, 1750-1756. With permission from Elsevier.)... 

Most unconformity-related deposits occur near the erosional edge of terrestrial units that overlie the unconformities. These terrestrial units are mostly unmetamorphosed Middle Proterozoic buff to red orthoquartzitic to feldspathic fluvial sandstones that may contain lenses of polymictic conglomerate near the unconformable contact and lenses of shale and siltstone higher in the sequence. 

Dahl [1965] has studied Permian bentonites from Texas and found illite-montmorillonite mixed layers, as well as mixtures of these minerals with chlorite. A study has been made of illites and mixed-layer illite-montmorillonites (in Montana, Illinois, Indiana, Colorado, Oklahoma) by Hower and Mowatt [1966]. These authors conclude that the nonexpandable layers are of lower change than true mica and contain lenses of trapped water. 

Figure B2.1.6 Femtosecond spectrometer for transient hole-burning spectroscopy with a continuum probe. Symbols used bs, 10% reflecting beamsplitter p, polarizer. The continuum generator consists of a focusing lens, a cell containing flowing water or ethylene glycol or, alternatively, a sapphire crystal and a recollimating lens.

A metal cylinder A contains two small holes. Into one of these the thermometer is placed and into the other (arranged centrally) is placed the melting-point tube. The cylinder is pierced by a hori-2ontaI tunnel so the melting-point tube can be observed during heating. A lens is... 

Figure 5.13 shows a typical experimental arrangement for obtaining the Raman spectmm of a gaseous sample. Radiation from the laser source is focused by the lens Lj into a cell containing the sample gas. The mirror Mj reflects this radiation back into the cell to increase... 

Endoscopes containing a CCD camera replace the fiber optic bundle with a smaU monochrome CCD chip at the focal point of the fish eye lens (4). 

CH2—CI2—) —(—CF2— CFH—) (39). Ceramic crystals have a higher piezoelectric efficiency. Their high acoustic impedance compared to body tissues necessitates impedance matching layers between the piezoelectric and the tissue. These layers are similar in function to the antireflective coatings on a lens. Polymer piezoelectric materials possess a more favorable impedance relative to body tissues but have poorer performance characteristics. Newer transducer materials are piezoelectric composites containing ceramic crystals embedded in a polymer matrix (see Composite materials, polymer-MATRIX Piezoelectrics). 

Many proprietary methods have been developed for casting and shaping DADC, especially for lenses. In one method DADC containing 3.5% diisopropyl percarbonate is prepolymerized by warming to a symp of viscosity 40—60 mm /s (=cSt) (15). Polymerization is continued in a lens for 18 h at 90°C followed by annealing at 120°C. 

Besides appHcation as heat-resistant molding powders for electronic and other appHcations, DAIP copolymers have been proposed for optical apphcations. Lenses of high impact resistance contain 50% DAIP, 20% benzyl methacrylate, and larger amounts of CR-39 (59). A lens of refractive index 71- = 1.569 andlow dispersion can be cast from phenyl methacrylate, DAIP, and isopropyl peroxide (60). Lenses of better impact properties can be obtained by modifying DAIP with aHyl benzoate (61). 

Hard lenses can be defined as plastic lenses that contain no water, have moduli in excess of 5 MPa (500 g/mm ), and have T well above the temperature of the ocular environment. Poly(methyl methacrylate) (PMMA) has excellent optical and mechanical properties and scratch resistance and was the first and only plastic used as a hard lens material before higher oxygen-permeable materials were developed. PMMA lenses also show excellent wetting in the ocular environment even though they are hydrophobic, eg, the contact angle is 66°. 

A good example of a surface-modified lens is the Sola/Bames-Hind Hydrocurve Flite lens, introduced in 1986. The material for the commercial Hydrocurve lens, bufilcon A [56030-52-5] contains methacrylic acid and has a high affinity for protein and subsequent deposition. The surface of the Flite lens was chemically modified with the addition of diazomethane (190) to reduce the surface charge. In vitro testing demonstrated a decrease in protein adsorption (191). 

In reality, below 550°C the driving force becomes so large that it cannot be contained and the iron transforms from f.c.c. to b.c.c. by the displaeive mechanism. Small lens-shaped grains of b.c.c. nucleate at f.c.c. grain boundaries and move across the... 

Spray-dried extract The solutions containing the drug extracts, which are sprayed through a nozzle, sink in the form of fine droplets in the current of warm air, losing their moisture and reaching the separator as dry and hollow pellets of extract which can be recognized with a hand lens. The spray-... 

The final set of magnetic lenses beneath the specimen are jointly referred to as post-specimen lenses. Their primary task is to magnify the signal transferred by the objective lens. Modern instruments typically contain four post-specimen lenses diffraction, intermediate, projector 1, and projector 2 (in, order of appearance below the specimen). They provide a TEM with its tremendous magnification flexibility. 

Natural crystals, synthetic crystals, and glasses often contain small bubbles that preserve samples of the fluid from which the crystals grew or of the atmosphere over the glass melt. Using a long focal length lens, the laser beam can be focused into inclusions at some depth below the crystal or glass surface. The Raman spectra then permit the identification of molecular species dissolved in the aqueous solutions or of components in the gas bubbles. ... 

Vision is vital for human activities, and eyes are very sensitive to a number of toxic insults induced by chemical compounds. The most serious outcome is permanent eye damage which may be so severe as to cause loss of vision. The eye consists of the cornea and conjunctiva, the choroid, the iris, and the ciliary body. It also contains the retina, which is of neural origin, and the optic nerve. The retina contains photoreceptors, a highly specific light-sensitive type of neural tissue. The eye also contains the lens and a small cerebrospinal fluid system, the aqueous humor system, that is important for the maintenance of the steady state of hydration of the lens and thus the transparency of the eye. 

The particle size analyzer, based on laser light diffraction, consists of a laser source, beam expander, collector lens, and detector (Fig. ] 3.45). The detector contains light diodes arranged to form a radial diode-array detector. The particle sample to be measured can be blown across the laser beam (dry sample), or it can be circulated via a measurement cell in a liquid suspension. In the latter case, the beam is direaed through the transparent cell. 

Instruments for the measurement of fluorescence are known as fluorimeters or spectrofluorimeters. The essential parts of a simple fluorimeter are shown in Fig. 18.1. The light from a mercury-vapour lamp (or other source of ultraviolet light) is passed through a condensing lens, a primary filter (to permit the light band required for excitation to pass), a sample container, a secondary filter (selected to absorb the primary radiant energy but transmit the fluorescent... 

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