Isotropi: Perbedaan revisi

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(←Membuat halaman berisi ''''Isotropi''' adalah keseragaman atau uniformitas dalam segala arah. Diturunkan dari kata Yunani ''isos'' (ίσος, "sama, setara") dan ''tropos''...')
 
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==Matematika==
WithinDalam [[mathematics]], ''isotropyisotropi'' hasmempunyai abeberapa few different meaningsarti:
; [[:en:Isotropic manifold|''isotropic manifold'']]s: ASuatu [[manifold]] is isotropic if the [[geometry]] on the manifold is the same regardless of direction. A similar concept is [[homogeneous space|homogeneity]]. A manifold can be homogeneous without being isotropic, but if it is inhomogeneous, it is necessarily anisotropic.
; [[Isotropic quadratic form]]: A [[quadratic form]] ''q'' is said to be isotropic if there is a non-zero vector ''v'' such that {{nowrap|1=''q''(''v'') = 0}}.
; [[Isotropic coordinates]] on an isotropic chart for [[Lorentzian manifolds]].
; [[Isotropy group]]: An isotropy group is the group of [[isomorphism]]s from any [[object (category theory)|object]] to itself in a [[groupoid]].<ref>A [[groupoid]] <math>\mathcal G</math> is a [[category (mathematics)|category]] where all [[morphism]]s are [[isomorphism]]s, i.e., invertible. If <math>G \in \mathcal G</math> is any object, then <math>\mathcal G(G,G)</math> denotes its [[isotropy group]]: the group of isomorphisms from <math>G</math> to <math>G</math>.</ref>
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==Physics Fisika ==
; [[QuantumMekanika mechanicskuantum]] oratau [[Particlefisika physicspartikel]]<!--: When a spinless particle (or even an unpolarized particle with spin) decays, the resulting decay distribution ''must'' be isotropic in the rest frame of the decaying particle regardless of the detailed physics of the decay. This follows from [[rotational invariance]] of the Hamiltonian, which in turn is guaranteed for a spherically symmetric potential.-->
:[[KineticTeori theorykinetik]] isjuga alsomerupakan ancontoh example of isotropyisotropi.<!-- It is assumed that the molecules move in random directions and as a consequence, there is an equal probability of a molecule moving in any direction. Thus when there are many molecules in the gas, with high probability there will be very similar numbers moving in one direction as any other hence demonstrating approximate isotropy.
 
; [[Fluid dynamics]]: Fluid flow is isotropic if there is no directional preference (e.g. in fully developed 3D turbulence). An example of anisotropy is in flows with a background density as gravity works in only one direction. The apparent surface separating two differing isotropic fluids would be referred to as an isotrope.
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; [[Ekspansi termal]]: suatu benda padat dikatakan isotropik jika ekspasi suatu benda padat itu sama ke segala arah ketika energi termal diberikan kepada benda padat itu.
 
; [[:en:Electromagnetism|Elektromagnetika]]: Suatu medium isotropik adalah sedemikian sehingga permitivitas (''permittivity''), ε, dan permeabilitas, μ, dari medium itu uniform ke segala arah dalam medium itu. Contoh paling sederhana adalah "ruang bebas" (''free space'').
; [[Thermal expansion]]: A solid is said to be isotropic if the expansion of solid is equal in all directions when thermal energy is provided to the solid.
 
; [[OpticsOptik]]: OpticalIsotropi isotropyoptikal meansartinya havingmempunyai thesifat sameoptika opticalyang propertiessama indi allsegala directionsarah.<!-- The individual [[reflectance]] or [[transmittance]] of the domains is averaged if the macroscopic reflectance or transmittance is to be calculated. This can be verified simply by investigating, e.g., a [[polycrystalline]] material under a polarizing microscope having the polarizers crossed: If the crystallites are larger than the resolution limit, they will be visible.-->
; [[Electromagnetism|Electromagnetics]]: An isotropic medium is one such that the permittivity, ε, and permeability, μ, of the medium are uniform in all directions of the medium, the simplest instance being free space.
 
; [[Optics]]: Optical isotropy means having the same optical properties in all directions. The individual [[reflectance]] or [[transmittance]] of the domains is averaged if the macroscopic reflectance or transmittance is to be calculated. This can be verified simply by investigating, e.g., a [[polycrystalline]] material under a polarizing microscope having the polarizers crossed: If the crystallites are larger than the resolution limit, they will be visible.
<div id="Cosmology"></div>
; [[CosmologyKosmologi]]: TheTeori [[Bigdentuman Bangdahsyat]] theoryyang ofmengawali theevolusi evolutionalam ofsemesta theyang observabledapat universedilihat assumesini thatberasumsi spacebahwa isruang isotropicangkasa bersifat isotropik.<ref name="autogenerated1">{{cite web|url=http://map.gsfc.nasa.gov/universe/bb_theory.html |title=WMAP Big Bang Theory |publisher=Map.gsfc.nasa.gov |date= |accessdate=2014-03-06}}</ref> ItJuga alsodiasumsikan assumesbahwa thatruang spaceangkasa isadalah homogeneoushomogen.<ref name="autogenerated1"/> TheseKedua twoasumsi assumptionsini togetherbersama-sama aredikenal known as thesebagai [[:en:Cosmological Principle|Prinsip Kosmologi]]. As<!--Sampai pada oftahun 2006, theobservasi observationsmendorong suggestpendapat thatbahwa, on distance scales much larger than galaxies, galaxy clusters are [[Great Wall (astronomy)|"Great"]] features, but small compared to so-called multi-verse scenarios.
 
===Materials science===
Isotropic materials are useful since they are easier to shape, and their behavior is easier to predict. Anisotropic materials can be tailored to the forces an object is expected to experience. For example, the fibers in [[carbon fiber]] materials and [[rebar]]s in [[reinforced concrete]] are oriented to withstand tension.
 
===MicrofabricationMikrofabrikasi===
In industrial processes, such as etching steps, isotropic means that the process proceeds at the same rate, regardless of direction. Simple chemical reaction and removal of a substrate by an acid, a solvent or a reactive gas is often very close to isotropic. Conversely, anisotropic means that the attack rate of the substrate is higher in a certain direction. Anisotropic etch processes, where vertical etch-rate is high, but lateral etch-rate is very small are essential processes in [[microfabrication]] of [[integrated circuits]] and [[Microelectromechanical systems|MEMS]] devices.
 
===AntennaAntena (radio)===
An [[isotropic antenna]] is an idealized "[[radiator|radiating element]]" used as a [[reference]]; an [[antenna (electronics)|antenna]] that broadcasts power equally (calculated by the [[Poynting vector]]) in all directions. The gain of an arbitrary antenna is usually reported in [[decibel]]s relative to an isotropic antenna, and is expressed as dBi or dB(i).
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==Biologi==
; [[Biologi sel]]: Jika sifat-sifat suatu [[dinding sel]] kurang lebih di segala arah, maka dikatakan bersifat isotropik. Bagian interior sel dikatakan anisotropik karena adanya [[organel]] intraseluler .
 
; [[Fisiologi]]: Dalam sel otot skeletal (atau [[:en:muscle fibers|muscle fibers]]), istilah "[[:en:isotropic bands|isotropik]]" merujuk kepada pita-pita terang ([[:en:I bands|pita jenis I]]) yang berkontribusi menghasilkan "''striated pattern''" pada sel-sel.
==Biology==
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; [[Cell biology]]: If the properties of the [[Cell (biology)|cell wall]] are more or less the same everywhere, it is said to be isotropic. The interior of the cell is anisotropic due to intracellular [[organelle]]s.
; [[PharmacologyFarmakologi]]: While it is well established that the skin provides an ideal site for the administration of local and systemic drugs, it presents a formidable barrier to the permeation of most substances.<ref>Landman L. “The Epidermal Permeability Barrier.” Anat Embryol (Berl) 1988; 178:1-13 [http://www.springerlink.com/content/x2v22259r84n6k75/]</ref> Most recently, [[isotropic formulations]] have been used extensively in dermatology for drug delivery.<ref>Gregoriadis G. “Lipsomes in Drug Delivery.” Harwood Academic Publishers, 1993; [http://books.google.com.au/books?hl=en&lr=&id=IqqYFne6deEC&oi=fnd&pg=PR7&dq=Liposomes+in+Drug+Delivery&ots=MSjlK_DRqc&sig=XKlC_NXQDndHXkVUepu8rIPaQrU]</ref>
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== Cabang ilmu lain ==
; ''[[Ekonomika]]'' dan ''[[Geografi]]'': suatu daerah isotropik adalah daerah yang mempunyai sifat-sifat yang sama di mana-mana. Daerah seperti itu merupakan suatu konstruksi yang dibutuhkan dalam banyak jenis model.
 
; [[Physiology]]: In skeletal muscle cells (a.k.a. [[muscle fibers]]), the term "[[isotropic bands|isotropic]]" refers to the light bands ([[I bands]]) that contribute to the striated pattern of the cells.
 
; [[Pharmacology]]: While it is well established that the skin provides an ideal site for the administration of local and systemic drugs, it presents a formidable barrier to the permeation of most substances.<ref>Landman L. “The Epidermal Permeability Barrier.” Anat Embryol (Berl) 1988; 178:1-13 [http://www.springerlink.com/content/x2v22259r84n6k75/]</ref> Most recently, [[isotropic formulations]] have been used extensively in dermatology for drug delivery.<ref>Gregoriadis G. “Lipsomes in Drug Delivery.” Harwood Academic Publishers, 1993; [http://books.google.com.au/books?hl=en&lr=&id=IqqYFne6deEC&oi=fnd&pg=PR7&dq=Liposomes+in+Drug+Delivery&ots=MSjlK_DRqc&sig=XKlC_NXQDndHXkVUepu8rIPaQrU]</ref>
 
==Other sciences==
; ''[[Economics]]'' and ''[[Geography]]'': An isotropic region is a region that has the same properties everywhere. Such a region is a construction needed in many types of models.
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== Lihat pula ==
{{Wiktionary}}