Glass quartz crystal

Alpha-quartz has many useful properties which lead to its wide use in industry as a glass, ceramic and molecular sieve. However, undoubtedly its most technically important use occurs by virtue of its piezo-electric properties, which allow it to be used as a frequency regulating device in satellites, computers, and the ubiquitous quartz-watch . Unfortunately, it has been found that quartz crystals are susceptible to damage by radiation, and that this is associated with the presence of defects in the crystal lattice. These defects, particularly aluminum and hydrogen, are grown into the crystal and so far have proved impossible to remove. This problem has been the cause of intensive research, which has led to some information on the possible types of defects involved, but has failed to produce details of their geometries, and the way in which they interact. 

C, is a cylindrical glass vessel with a volume of 450 cm. The piezometer contains the solution and 330 gms of Hg. The top of the piezometer is fitted with a Taper joint for filling. A precision bore capillary, E, (2mm in diameter) is fitted to the bottom of the piezometer. The piezometer is suspended (6) in a brass or stainless steel pressure vessel, H. A glass boiler tube, J, encloses the upper portion of the capillary. The pressure vessel is filled with ethylene glycol which serves as a thermal and pressure medium. The entire apparatus is submerged in a constant temperature bath controlled to 0.001 C. The temperature inside the pressure vessel is monitored with a Hewlett-Packard quartz crystal thermometer (to determine when thermal equilibrium is reached after compression and decompression). 

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Silicon glass is made by fusing pure quartz crystals or glass sand (impure crystals), and it is typically about 99.8% silicon dioxide. It is high-melting and difficult to fabricate. 

The history of electrochemical sensors began in the thirties of the twentieth century, when the pH-sensitive glass electrode was deployed, but no noteworthy development was carried out till the middle of that century. In 1956, Clark invented his oxygen-sensor based on a Ft electrode in 1959, the first piezoelectric mass-deposition sensor (a quartz crystal microbal-ance) was produced. In the sixties, the first biosensors (Clark and Lyons, 1962) and the first metal oxide semiconductor-based gas sensors (Taguchi, 1962) started to appear. 

The word crystal often meant with the ancients quartz crystal, but it is very evident that with the authors of these notes the term was used in a more comprehensive sense to include other transparent or translucent stones. This use is very evident in the many recipes for imitation of precious stones, where the processes involve a degree of porosity or absorbent power towards colored solutions not possessed either by quartz crystal or by glass, while certain agates, micas, alabasters or other stones possess this property. In case of the above recipe, it is doubtful whether any such mordanting would in a reasonable time roughen the surface of real quartz crystal adequately. The quicksilver here mentioned is evidently the same substance of pearly luster previously referred to. 

Cnthidia fasciculata - [SILICA - INTRODUCTION] (Vol21) - [CLAYS - SURVEY] (Vol 6) - [SILICA - SYNTHETIC QUARTZ CRYSTALS] (Vol 21) - [GLASS] (Vol 12) -from diatomite piATOMITE] (Vol 8) -OSHA specifications [ABRASIVES] (Vol 1) -m silica refractories [REFRACTORIES] (Vol 21) - [ANTIBIOTICS - ANSAMACROLIDES] (Vol 2)... 

Quartz crystals are composed of silica, Si02. When the silica is pure, as here, it is colorless. The internal structure of quartz is highly complex, but can be pictured in terms of tetrahedral Si04 units, linked through shared oxygen atoms. When quartz crystals melt and solidify again, they may form an amorphous material known as a glass, in which the tetrahedral units form a more random jumble. 

In this chapter we have considered three-dimensional ceramic constructions and nature s three-dimensional crystalline structures and glasses. There are many similarities between the construction of a ceramic work of art and the construction of a crystalline solid or glass. In both cases, units are built into a structure. The units are bonded together in a variety of ways. Both can result in pleasing works for the viewer to enjoy. A quartz crystal, made of silicon dioxide (Si02), can be just as beautiful as a carefully crafted ceramic piece. Particular elements of design make these objects beautiful. When considering ceramic pieces and natural crystals, texture is an important element. 

Microsystems can be built on various substrates with a range of materials crystalline silicon, amorphous silicon, glass, quartz, metals, and organic polymers. Single-crystal silicon substrates have been used in most areas of microfabrication for a range of excellent reasons ... 

A quartz crystal sensor chip was bonded with a microfluidic glass chip for acoustic wave detection (see Figure 7.46). The sensor was operated in the thickness-shear mode (TSM). This has allowed rat heart muscle cell contraction to be studied based on the measurement of the resonant frequency changes [133]. 

Fig. 1.1 The molecular structure of a quartz crystal and quartz glass.

Historically, fused quartz referred to transparent products produced from quartz crystal rock, and fused silica referred to opaque products produced from sand. With the advent of new manufacturing techniques, transparent products can now be produced from sand, so the old distinction is no longer applicable. Currently, the term fused quartz is used whenever the raw product is either quartz rock or sand. The term fused silica is used whenever the raw product is synthetically derived (from SiCl4). Generically, the term quartz glass or, better yet, vitreous silica can be used to cover the whole range of materials. 

We next discuss how to wavelength-select visible radiation. There have been two traditional kinds of optical elements prisms and gratings (Fig. 2.20). In particular, the Bunsen103 prism is a 60° prism, made of fused silica (normal glass absorbs too much light below 350 nm) a single natural quartz crystal is... 

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