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Icosahedral Nanoparticle
An icosahedral twin is an atomic structure found in atomic Cluster (physics), clusters and also nanoparticles with some thousands of atoms. Their atomic structure is slightly different from what is found for bulk materials, and contains five-fold symmetries. They have been analyzed in many areas of science including crystal growth, crystallography, chemical physics, surface science and materials science, and are sometimes considered as beautiful due to their high symmetry. The simplest form of these clusters is twenty interlinked tetrahedron, tetrahedral crystals joined along triangular (e.g. Miller index, cubic-(111)) faces, although more complex variants of the outer surface also occur. A related structure has five units similarly arranged with Crystal twinning, twinning, which were known as "fivelings" in the 19th century,H. Hofmeister (2004) "Fivefold twinned nanoparticles" in ''Encyclopedia of Nanoscience and Nanotechnology'' (ed. H. S. Nalwa, Amer. Sci. Publ., Stevenson Ran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
561 Atom Icosahedral Nanoparticle
__NOTOC__ Year 561 (Roman numerals, DLXI) was a common year starting on Saturday of the Julian calendar. The denomination 561 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years. Events By place Europe * November 29 – King Chlothar I ("the Old") dies at Compiègne at age 64. The Merovingian dynasty is continued by his four sons (Charibert I, Guntram, Sigebert I and Chilperic I), who divide the Francia, Frankish Kingdom and rule from the capitals at Paris, Orléans, Reims and Soissons, respectively. Britain * The Battle of Cúl Drebene (modern Ireland) is fought between the Northern and Southern Uí Néill (approximate date). Asia * Winter – Emperor Wucheng of Northern Qi, Wu Cheng Di succeeds his brother Emperor Xiaozhao of Northern Qi, Xiao Zhao Di, who dies from injuries suffered while hunting, as Chinese emperor of Northern Qi. Americas * Sky Witne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surface Energy
In surface science, surface energy (also interfacial free energy or surface free energy) quantifies the disruption of intermolecular bonds that occurs when a surface is created. In solid-state physics, surfaces must be intrinsically less energetically favorable than the bulk of the material (that is, the atoms on the surface must have more energy than the atoms in the bulk), otherwise there would be a driving force for surfaces to be created, removing the bulk of the material by sublimation. The surface energy may therefore be defined as the excess energy at the surface of a material compared to the bulk, or it is the work required to build an area of a particular surface. Another way to view the surface energy is to relate it to the work required to cut a bulk sample, creating two surfaces. There is "excess energy" as a result of the now-incomplete, unrealized bonding between the two created surfaces. Cutting a solid body into pieces disrupts its bonds and increases the surfac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Icosidodecahedron
In geometry, an icosidodecahedron or pentagonal gyrobirotunda is a polyhedron with twenty (''icosi-'') triangular faces and twelve (''dodeca-'') pentagonal faces. An icosidodecahedron has 30 identical Vertex (geometry), vertices, with two triangles and two pentagons meeting at each, and 60 identical edges, each separating a triangle from a pentagon. As such, it is one of the Archimedean solids and more particularly, a quasiregular polyhedron. Construction One way to construct the icosidodecahedron is to start with two pentagonal rotunda by attaching them to their bases. These rotundas cover their decagonal base so that the resulting polyhedron has 32 faces, 30 vertices, and 60 edges. This construction is similar to one of the Johnson solids, the pentagonal orthobirotunda. The difference is that the icosidodecahedron is constructed by twisting its rotundas by 36°, a process known as gyration, resulting in the pentagonal face connecting to the triangular one. The icosidodecahedr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Truncated Icosahedron
In geometry, the truncated icosahedron is a polyhedron that can be constructed by Truncation (geometry), truncating all of the regular icosahedron's vertices. Intuitively, it may be regarded as Ball (association football), footballs (or soccer balls) that are typically patterned with white hexagons and black pentagons. It can be found in the application of geodesic dome structures such as those whose architecture Buckminster Fuller pioneered are often based on this structure. It is an example of an Archimedean solid, as well as a Goldberg polyhedron. Construction The truncated icosahedron can be constructed from a regular icosahedron by cutting off all of its vertices, known as Truncation (geometry), truncation. Each of the 12 vertices at the one-third mark of each edge creates 12 pentagonal faces and transforms the original 20 triangle faces into regular hexagons. Therefore, the resulting polyhedron has 32 faces, 90 edges, and 60 vertices. A Goldberg polyhedron is one whose f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Icosahedron
In geometry, an icosahedron ( or ) is a polyhedron with 20 faces. The name comes . The plural can be either "icosahedra" () or "icosahedrons". There are infinitely many non- similar shapes of icosahedra, some of them being more symmetrical than others. The best known is the ( convex, non- stellated) regular icosahedron—one of the Platonic solids—whose faces are 20 equilateral triangles. Regular icosahedra There are two objects, one convex and one nonconvex, that can both be called regular icosahedra. Each has 30 edges and 20 equilateral triangle faces with five meeting at each of its twelve vertices. Both have icosahedral symmetry. The term "regular icosahedron" generally refers to the convex variety, while the nonconvex form is called a ''great icosahedron''. Convex regular icosahedron The convex regular icosahedron is usually referred to simply as the ''regular icosahedron'', one of the five regular Platonic solids, and is represented by its Schläfli symbol , contai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Icosahedral Twins
An icosahedral twin is an atomic structure found in atomic clusters and also nanoparticles with some thousands of atoms. Their atomic structure is slightly different from what is found for bulk materials, and contains five-fold symmetries. They have been analyzed in many areas of science including crystal growth, crystallography, chemical physics, surface science and materials science, and are sometimes considered as beautiful due to their high symmetry. The simplest form of these clusters is twenty interlinked tetrahedral crystals joined along triangular (e.g. cubic-(111)) faces, although more complex variants of the outer surface also occur. A related structure has five units similarly arranged with twinning, which were known as "fivelings" in the 19th century,H. Hofmeister (2004) "Fivefold twinned nanoparticles" in ''Encyclopedia of Nanoscience and Nanotechnology'' (ed. H. S. Nalwa, Amer. Sci. Publ., Stevenson Ranch CA) vol. 3, pp. 431-452pdf and more recently as "decahedral ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extended Wulff Constructions
Extended Wulff constructions refers to a number of different ways to model the structure of nanoparticles as well as larger mineral crystals. They can be used to understand the shape of gemstones and Crystal twinning, crystals with twins, and in other areas such as understanding both the shape and how nanoparticles play a role in the commercial production of chemicals using Heterogeneous catalysis, heterogeneous catalysts. Extended Wulff constructions are variants of the Wulff construction, which is used for a solid single crystal in isolation. They include cases for solid particles on substrates, those with internal boundaries and also when growth is important. Depending upon whether there are twins or a substrate, there are different cases as indicated in the Extended Wulff constructions#Figure 1, decision tree figure. The simplest forms of these constructions yield the lowest Gibbs free energy (thermodynamic) shape, or the stable growth form for an isolated particle; it can be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Facet
Facets () are flat faces on geometric shapes. The organization of naturally occurring facets was key to early developments in crystallography, since they reflect the underlying symmetry of the crystal structure. Gemstones commonly have facets cut into them in order to improve their appearance by allowing them to reflect light. The earliest diamond cutting techniques were simply to polish the natural shape of rough diamonds, often octahedral crystals. It wasn't until the 14th century that faceting, the process of cutting and polishing a gemstone to create multiple flat surfaces or facets, was first developed in Europe. Facet arrangements Of the hundreds of facet arrangements that have been used, the most famous is probably the round brilliant cut, used for diamond and many colored gemstones. This first early version of what would become the modern Brilliant Cut is said to have been devised by an Italian named Peruzzi, sometime in the late 17th century.Gems, 5th edition, Webster ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Icosahedral Symmetry
In mathematics, and especially in geometry, an object has icosahedral symmetry if it has the same symmetries as a regular icosahedron. Examples of other polyhedra with icosahedral symmetry include the regular dodecahedron (the dual polyhedron, dual of the icosahedron) and the rhombic triacontahedron. Every polyhedron with icosahedral symmetry has 60 Rotational symmetry, rotational (or orientation-preserving) symmetries and 60 orientation-reversing symmetries (that combine a rotation and a Reflection symmetry, reflection), for a total symmetry order of 120. The full symmetry group is the Coxeter group of type . It may be represented by Coxeter notation and Coxeter diagram . The set of rotational symmetries forms a subgroup that is isomorphic to the alternating group on 5 letters. As point group Apart from the two infinite series of prismatic and antiprismatic symmetry, rotational icosahedral symmetry or chiral icosahedral symmetry of chiral objects and full icosahedra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silver
Silver is a chemical element; it has Symbol (chemistry), symbol Ag () and atomic number 47. A soft, whitish-gray, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any metal. Silver is found in the Earth's crust in the pure, free elemental form ("native metal, native silver"), as an alloy with gold and other metals, and in minerals such as argentite and chlorargyrite. Most silver is produced as a byproduct of copper, gold, lead, and zinc Refining (metallurgy), refining. Silver has long been valued as a precious metal. Silver metal is used in many bullion coins, sometimes bimetallism, alongside gold: while it is more abundant than gold, it is much less abundant as a native metal. Its purity is typically measured on a per-mille basis; a 94%-pure alloy is described as "0.940 fine". As one of the seven metals of antiquity, silver has had an enduring role in most human cultures. Other than in currency and as an in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gold
Gold is a chemical element; it has chemical symbol Au (from Latin ) and atomic number 79. In its pure form, it is a brightness, bright, slightly orange-yellow, dense, soft, malleable, and ductile metal. Chemically, gold is a transition metal, a group 11 element, and one of the noble metals. It is one of the least reactivity (chemistry), reactive chemical elements, being the second-lowest in the reactivity series. It is solid under standard temperature and pressure, standard conditions. Gold often occurs in free elemental (native state (metallurgy), native state), as gold nugget, nuggets or grains, in rock (geology), rocks, vein (geology), veins, and alluvial deposits. It occurs in a solid solution series with the native element silver (as in electrum), naturally alloyed with other metals like copper and palladium, and mineral inclusions such as within pyrite. Less commonly, it occurs in minerals as gold compounds, often with tellurium (gold tellurides). Gold is resistant to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
