Information & explanations, latest texts & monographs on
Crystal (including recent related patents.)
CrystalA crystal is a solid in which the constituent atoms, molecules, or ions are packed in a regularly ordered, repeating pattern extending in all three spatial dimensions. Generally, fluid substances form crystals when they undergo a process of solidification. Under ideal conditions, the result may be a single crystal, where all of the atoms in the solid fit into the same lattice or crystal structure, but generally many crystals form simultaneously during solidification, leading to a polycrystalline solid. For example, most metals encountered in everyday life are polycrystals. Which crystal structure the fluid will form depends on the chemistry of the fluid, the conditions under which it is being solidified, and also on the ambient pressure. See the entry on phase for more information. The process of forming a crystalline structure is often referred to as crystallization. While the process of cooling usually results in the generation of a crystalline material, under certain conditions the fluid may be frozen in a noncrystalline state. In most cases, this involves cooling the fluid so rapidly that atoms cannot travel to their lattice sites before they lose mobility. A noncrystalline material, which has no long-range order, is called an amorphous, vitreous, or glassy material. It is also often referred to as an amorphous solid, although there are distinct differences between solids and glasses: most notably, the process of forming a glass does not release the latent heat of fusion. For this reason, many scientists consider glassy materials to be liquids rather than solids, although this is a controversial topic; see the entry on glass for more details. Crystalline structures occur in all classes of materials, with all types of chemical bonds. Almost all metal exists in a polycrystalline state; amorphous or single-crystal metals must be produced synthetically, often with great difficulty. Ionically bonded crystals can form upon solidification of salts, either from a molten fluid or when it condenses from a solution. Covalently bonded crystals are also very common, notable examples being diamond, silica, and graphite. Polymer materials generally will form crystalline regions, but the lengths of the molecules usually prevents complete crystallization. Weak Van der Waals forces can also play a role in a crystal structure; for example, this type of bonding loosely holds together the hexagonal-patterned sheets in graphite. Most crystalline materials have a variety of crystallographic defects. The types and structures of these defects can have a profound effect on the properties of the materials. While the term "crystal" has a precise meaning within materials science and solid-state physics, colloquially "crystal" refers to solid objects that exhibit well-defined and often pleasing geometric shapes. Various shapes of such crystals are found in nature. The shape of these crystals is dependent on the types of molecular bonds between the atoms to determine the structure, as well as on the conditions under which they formed. Snowflakes, diamonds, and common salt are common examples of crystals. Some crystalline materials may exhibit special electrical properties such as the ferroelectric effect or the piezoelectric effect. The behaviour of light in crystals is described by crystal optics. In periodic dielectric structures a range of unique optical properties can be expected as described in photonic crystals. See also: Crystal structure, crystal habit, crystallite Other meanings Crystal is also used in different contexts:This article is adapted from from Wikipedia All Wikipedia article text is available under the terms of the GNU Free Documentation License Recent Crystal related patents From USPTO: 6715131: Method and system for providing resource access in a mobile environment 6715063: Call gate expansion for 64 bit addressing 6715051: Program modification device 6715045: Host cache for haptic feedback effects 6715042: Systems and methods for multiport memory access in a multimaster environment 6715034: Switching file system request in a mass storage system 6715007: Method of regulating a flow of data in a communication system and apparatus therefor 6715003: Digital camera and method for communicating digital image and at least one address image stored in the camera to a remotely located service provider 6714989: ATM controller and ATM communication control device 6714984: Method and apparatus for media data transmission 6714983: Modular, portable data processing terminal for use in a communication network 6714981: Addressing system and method for communicating data 6714971: Method and system for remote diagnostic, control and information collection based on various communication modes for sending messages to users 6714969: Mobile terminal with integrated host application software 6714932: Display-equipped information terminal device having mailing function and electronic mail transmitting method 6714920: Information processing apparatus and information processing method 6714903: Placement and routing of circuits using a combined processing/buffer cell 6714891: Method and apparatus for thermal management of a power supply to a high performance processor in a computer system 6714881: Time reference compensation for improved metering accuracy 6714875: Method for producing and screening mass-coded combinatorial libraries for drug discovery and target validation 6714871: Method for quantifying permeability of vuggy carbonates using wireline logs 6714861: Map displaying method and apparatus, and navigation system having the map displaying apparatus 6714833: Performance evaluation method for plasma processing apparatus 6714819: System and method of automatically adjusting auto capture safety margin 6714815: Method for the iontophoretic non-invasive determination of the in vivo concentration level of an inorganic or organic substance 6714812: Method of performing operating settings in heart rate measurement arrangement, and heart rate measurement arrangement 6714791: System, apparatus and method for location-based instant messaging 6714776: System and method for an image rejecting single conversion tuner with phase error correction 6714775: Interference canceller 6714772: Wireless communication system 6714768: Structure and method for fabricating semiconductor structures and polarization modulator devices utilizing the formation of a compliant substrate 6714747: Image forming apparatus with different recording sheets feeding and discharging features 6714743: Wide range tunable filter 6714729: Automatic motion-controlled photographing apparatus and related photographing method 6714717: Time base corrector 6714695: Optical transmission system employing auto-synchronized chirped return-to-zero transmitter 6714692: Image scaling method and apparatus using continuous domain filtering and interpolation method 6714691: Exposure method and apparatus, and device manufacturing method using the same 6714684: Subband image compression of blocks within a bounded shape using a resolution transform 6714671: Method of detecting pattern defects 6714670: Methods and apparatuses to determine the state of elements 6714669: Image processing apparatus 6714667: User interface for imaging system 6714653: Sound capturing method and device 6714625: Lithography device for semiconductor circuit pattern generation 6714623: Image collecting system 6714590: Integrated modem and line-isolation circuitry and associated method 6714579: Basic hydrogen peroxide recycling system for chemical oxygen-iodine lasers 6714578: Calcium gallium sulphide (CaGa2S4) as a high gain erbium host |
