text stringlengths 2 4.67k | source dict |
|---|---|
In quantum mechanics, the probability current (sometimes called probability flux) is a mathematical quantity describing the flow of probability. Specifically, if one thinks of probability as a heterogeneous fluid, then the probability current is the rate of flow of this fluid. It is a real vector that changes with spac... | {
"page_id": 3545648,
"title": "Probability current"
} |
proportional to a Wronskian W ( Ψ , Ψ ∗ ) . {\displaystyle W(\Psi ,\Psi ^{*}).} In three dimensions, this generalizes to j = ℏ 2 m i ( Ψ ∗ ∇ Ψ − Ψ ∇ Ψ ∗ ) = ℏ m ℜ { Ψ ∗ ∇ i Ψ } = ℏ m ℑ { Ψ ∗ ∇ Ψ } , {\displaystyle \mathbf {j} ={\frac {\hbar }{2mi}}\left(\Psi ^{*}\mathbf {\nabla } \Psi -\Psi \mathbf {\nabla } \Psi ^{*}\... | {
"page_id": 3545648,
"title": "Probability current"
} |
)|\Psi (t)\rangle .} === Spin-0 particle in an electromagnetic field === The above definition should be modified for a system in an external electromagnetic field. In SI units, a charged particle of mass m and electric charge q includes a term due to the interaction with the electromagnetic field; j = 1 2 m [ ( Ψ ∗ p ^... | {
"page_id": 3545648,
"title": "Probability current"
} |
2 ] + μ S c s ℏ ∇ × ( Ψ ∗ S Ψ ) {\displaystyle \mathbf {j} _{e}={\frac {q}{2m}}\left[\left(\Psi ^{*}\mathbf {\hat {p}} \Psi -\Psi \mathbf {\hat {p}} \Psi ^{*}\right)-{\frac {2q}{c}}\mathbf {A} |\Psi |^{2}\right]+{\frac {\mu _{S}c}{s\hbar }}\nabla \times (\Psi ^{*}\mathbf {S} \Psi )} And in SI units: j e = q 2 m [ ( Ψ ∗... | {
"page_id": 3545648,
"title": "Probability current"
} |
and μS= 2.7927·μN or the deuteron (H-2 nucleus) which has s=1 and μS=0.8574·μN – it is mathematically possible but doubtful. == Connection with classical mechanics == The wave function can also be written in the complex exponential (polar) form: Ψ = R e i S / ℏ {\displaystyle \Psi =Re^{iS/\hbar }} where R, S are real f... | {
"page_id": 3545648,
"title": "Probability current"
} |
combining and cancelling the constants, and replacing R2 with ρ, j = ρ ∇ S m . {\displaystyle \mathbf {j} =\rho {\frac {\mathbf {\nabla } S}{m}}.} Hence, the spatial variation of the phase of a wavefunction is said to characterize the probability flux of the wavefunction. If we take the familiar formula for the mass fl... | {
"page_id": 3545648,
"title": "Probability current"
} |
density (probability per unit volume, * denotes complex conjugate). Then, d d t ∫ V d V ρ = ∫ V d V ( ∂ ψ ∂ t ψ ∗ + ψ ∂ ψ ∗ ∂ t ) = ∫ V d V [ − i ℏ ( − ℏ 2 2 m ∇ 2 ψ + V ψ ) ψ ∗ + i ℏ ( − ℏ 2 2 m ∇ 2 ψ ∗ + V ψ ∗ ) ψ ] = ∫ V d V i ℏ 2 m [ ( ∇ 2 ψ ) ψ ∗ − ψ ( ∇ 2 ψ ∗ ) ] = ∫ V d V ∇ ⋅ ( i ℏ 2 m ( ψ ∗ ∇ ψ − ψ ∇ ψ ∗ ) ) = ... | {
"page_id": 3545648,
"title": "Probability current"
} |
1 2 m ( Ψ ∗ p ^ Ψ − Ψ p ^ Ψ ∗ ) = − i ℏ 2 m ( ψ ∗ ∇ ψ − ψ ∇ ψ ∗ ) = ℏ m Im ( ψ ∗ ∇ ψ ) {\displaystyle \mathbf {j} ={\frac {1}{2m}}\left(\Psi ^{*}{\hat {\mathbf {p} }}\Psi -\Psi {\hat {\mathbf {p} }}\Psi ^{*}\right)=-{\frac {i\hbar }{2m}}(\psi ^{*}\nabla \psi -\psi \nabla \psi ^{*})={\frac {\hbar }{m}}\operatorname {I... | {
"page_id": 3545648,
"title": "Probability current"
} |
arises from Noether's theorem as applied to the Lagrangian the Klein-Gordon Lagrangian density L = ∂ μ ϕ ∗ ∂ μ ϕ + V ( ϕ ∗ ϕ ) {\displaystyle {\mathcal {L}}=\partial _{\mu }\phi ^{*}\,\partial ^{\mu }\phi +V(\phi ^{*}\,\phi )} of the complex scalar field ϕ : R n + 1 ↦ C \phi :\mathbb {R} ^{n+1}\mapsto \mathbb {C} . Thi... | {
"page_id": 3545648,
"title": "Probability current"
} |
t ϕ − ϕ ∂ t ϕ ∗ {\displaystyle \phi ^{*}\partial _{t}\phi -\phi \partial _{t}\phi ^{*}} . As this quantity can now be negative, we must interpret it as a charge density, with an associated current density and 4-current. === Transmission and reflection through potentials === In regions where a step potential or potentia... | {
"page_id": 3545648,
"title": "Probability current"
} |
}{\mathbf {j} _{\mathrm {inc} }\cdot \mathbf {n} }}\right|\,,} where the absolute values are required to prevent T and R being negative. == Examples == === Plane wave === For a plane wave propagating in space: Ψ ( r , t ) = A e i ( k ⋅ r − ω t ) {\displaystyle \Psi (\mathbf {r} ,t)=\,Ae^{i(\mathbf {k} \cdot {\mathbf {r... | {
"page_id": 3545648,
"title": "Probability current"
} |
\Psi _{n}=\Psi _{n}^{*}} == Discrete definition == For a particle in one dimension on ℓ 2 ( Z ) , {\displaystyle \ell ^{2}(\mathbb {Z} ),} we have the Hamiltonian H = − Δ + V {\displaystyle H=-\Delta +V} where − Δ ≡ 2 I − S − S ∗ {\displaystyle -\Delta \equiv 2I-S-S^{\ast }} is the discrete Laplacian, with S being the ... | {
"page_id": 3545648,
"title": "Probability current"
} |
}}(x)\left(-\Psi (x-1)+\Psi (x+1)\right)\right\}\end{aligned}}} == References == == Further reading == Resnick, R.; Eisberg, R. (1985). Quantum Physics of Atoms, Molecules, Solids, Nuclei and Particles (2nd ed.). John Wiley & Sons. ISBN 0-471-87373-X. | {
"page_id": 3545648,
"title": "Probability current"
} |
The International Astronomical Union at its 16th General Assembly in Grenoble in 1976, accepted Resolution No. 1 regarding a "New System of Astronomical Constants" recommended for reduction of astronomical observations, and for computation of ephemerides. It superseded the IAU's previous recommendations of 1964 (see IA... | {
"page_id": 38869556,
"title": "IAU (1976) System of Astronomical Constants"
} |
as the length for which the gravitational constant, more specifically the Gaussian gravitational constant k expressed in the astronomical units (i.e., k2 has units A3S−1D−2), takes the value of 0.017 202 098 95. This astronomical unit is approximately the mean distance between the Earth and the Sun. The value of k is t... | {
"page_id": 38869556,
"title": "IAU (1976) System of Astronomical Constants"
} |
The molecular formula C14H20N2O3 (molar mass: 264.32 g/mol, exact mass: 264.1474 u) may refer to: Propacetamol Vorinostat, also known as suberanilohydroxamic acid | {
"page_id": 24320566,
"title": "C14H20N2O3"
} |
Charles Darwin Research Station (CDRS) (Spanish: Estación Científica Charles Darwin, ECCD) is a biological research station in Puerto Ayora, Santa Cruz Island, Galápagos, Ecuador. The station is operated by the Charles Darwin Foundation which was founded in 1959 under the auspices of UNESCO and the World Conservation U... | {
"page_id": 3349049,
"title": "Charles Darwin Research Station"
} |
in charge of conservation and natural resource issues in the Galapagos. The work of the CDRS has as its main objectives: To promote, facilitate, design, and implement the scientific investigation necessary for the understanding of biological principles, better understanding of ecosystems, and adequate management of the... | {
"page_id": 3349049,
"title": "Charles Darwin Research Station"
} |
The conductance quantum, denoted by the symbol G0, is the quantized unit of electrical conductance. It is defined by the elementary charge e and Planck constant h as: G 0 = 2 e 2 h = 4 α ϵ 0 c {\displaystyle G_{0}={\frac {2e^{2}}{h}}=4\alpha \epsilon _{0}c} = 7.748091729...×10−5 S. It appears when measuring the conduct... | {
"page_id": 3873342,
"title": "Conductance quantum"
} |
going across is the current density: j = − e v ( μ 1 − μ 2 ) d n d ϵ . {\displaystyle j=-ev(\mu _{1}-\mu _{2}){\frac {\mathrm {d} n}{\mathrm {d} \epsilon }}.} This results in a quantized conductance: G 0 = I V = j V = 2 e 2 h . {\displaystyle G_{0}={\frac {I}{V}}={\frac {j}{V}}={\frac {2e^{2}}{h}}.} == Occurrence == Qu... | {
"page_id": 3873342,
"title": "Conductance quantum"
} |
Particle size analysis, particle size measurement, or simply particle sizing, is the collective name of the technical procedures, or laboratory techniques which determines the size range, and/or the average, or mean size of the particles in a powder or liquid sample. Particle size analysis is part of particle science, ... | {
"page_id": 16521792,
"title": "Particle size analysis"
} |
function of time, the technique is considered absolute and the DLS instruments do not require calibration. Amongst its disadvantages is the fact that it does not properly resolve highly polydisperse samples, while the presence of large particles can affect size accuracy. Other scattering techniques have emerged, such a... | {
"page_id": 16521792,
"title": "Particle size analysis"
} |
rapid measurement, high reproducibility and the capability to perform online measurements. However, these devices are generally large in size (~700 × 300 × 450 mm), heavy (~30 kg) and expensive (in the 50–200 K€ range). On the one hand, the large size of common devices is due to the large distance needed between the sa... | {
"page_id": 16521792,
"title": "Particle size analysis"
} |
investments and operational costs. Another approach is to apply multiple scattering correction models together with the optical models to compute the PSD. A large number of algorithms for multiple scattering correction can be found in the literature. However, these algorithms typically require implementing a complex co... | {
"page_id": 16521792,
"title": "Particle size analysis"
} |
cocoa powder. It is especially helpful with chocolate quality to ensure there is a consistent taste and feeling when eaten. Furthermore, in the case of food emulsions, particle size analysis is relevant to predict stability and shelf-life, and optimize homogenization. == Agriculture == The gradation of soils, or soil t... | {
"page_id": 16521792,
"title": "Particle size analysis"
} |
particle depends on the method used for its measurement, and it is important to choose the method that is most relevant to the application. The "See also" section covers many of these techniques. In most of them, the particle size is inferred from a measurement of, for example: light scattering; electrical resistance; ... | {
"page_id": 16521792,
"title": "Particle size analysis"
} |
In chemistry, neutralization or neutralisation (see spelling differences) is a chemical reaction in which acid and a base react with an equivalent quantity of each other. In a reaction in water, neutralization results in there being no excess of hydrogen or hydroxide ions present in the solution. The pH of the neutrali... | {
"page_id": 531014,
"title": "Neutralization (chemistry)"
} |
present initially. This amount of base is said to be the equivalent amount. In a titration of an acid with a base, the point of neutralization can also be called the equivalence point. The quantitative nature of the neutralization reaction is most conveniently expressed in terms of the concentrations of acid and alkali... | {
"page_id": 531014,
"title": "Neutralization (chemistry)"
} |
ion exists as the hydronium ion, so that the neutralization reaction may be written as H3O+ + OH− → H2O + H2O When a strong acid is neutralized by a strong base there are no excess hydrogen ions left in the solution. The solution is said to be neutral as it is neither acidic nor alkaline. The pH of such a solution is c... | {
"page_id": 531014,
"title": "Neutralization (chemistry)"
} |
with a strong acid, but depends on the acid dissociation constant, Ka, of the acid. The pH at the end-point or equivalence point in a titration may be calculated as follows. At the end-point the acid is completely neutralized so the analytical hydrogen ion concentration, TH, is zero and the concentration of the conjuga... | {
"page_id": 531014,
"title": "Neutralization (chemistry)"
} |
steeply as the end-point is approached. At the end-point, the slope of the curve of pH with respect to amount of titrant is a maximum. Since the end-point occurs at pH greater than 7, the most suitable indicator to use is one, like phenolphthalein, that changes color at high pH. == Weak bases and strong acids == The si... | {
"page_id": 531014,
"title": "Neutralization (chemistry)"
} |
to benzoate. == Applications == Chemical titration methods are used for analyzing acids or bases to determine the unknown concentration. Either a pH meter or a pH indicator which shows the point of neutralization by a distinct color change can be employed. Simple stoichiometric calculations with the known volume of the... | {
"page_id": 531014,
"title": "Neutralization (chemistry)"
} |
are made by neutralizing sulfuric acid (H2SO4) or nitric acid (HNO3) with ammonia gas (NH3), making ammonium sulfate or ammonium nitrate. These are salts utilized in the fertilizer. Industrially, a by-product of the burning of coal, sulfur dioxide gas, may combine with water vapor in the air to eventually produce sulfu... | {
"page_id": 531014,
"title": "Neutralization (chemistry)"
} |
Immune Therapy Holdings AB or ITH is a Swedish biotechnology R&D holding company headquartered at the Karolinska Institutet and Karolinska University Hospital in Stockholm. ITH's research is primarily focused on its Tailored Leukapheresis (TLA) treatment for immune mediated inflammatory diseases (IMIDs). == Tailored Le... | {
"page_id": 42277447,
"title": "Immune Therapy Holdings"
} |
CAGR of 5.8% between 2010 and 2017 to a total value of $85.9 billion. == References == | {
"page_id": 42277447,
"title": "Immune Therapy Holdings"
} |
Norlevorphanol is an opioid analgesic of the morphinan family that was never marketed. It is the levo-isomer of 3-hydroxymorphinan (morphinan-3-ol). Norlevorphanol is a Schedule I Narcotic controlled substance in the United States with an ACSCN of 9634 and in 2014 it had an annual aggregate manufacturing quota of 52 gr... | {
"page_id": 26876486,
"title": "Norlevorphanol"
} |
The molecular formula C5H10O5 may refer to: Apiose Aldopentoses Arabinose Lyxose Ribose Xylose 1,2,3,4,5-Cyclopentanepentol Ketopentoses Ribulose Xylulose | {
"page_id": 12261961,
"title": "C5H10O5"
} |
The molecular formula C5H4N4O (molar mass: 136.11 g/mol, exact mass: 136.0385 u) may refer to: Allopurinol 1-Hydroxy-7-azabenzotriazole (HOAt) Hypoxanthine | {
"page_id": 12261967,
"title": "C5H4N4O"
} |
Wheat is an English-language surname. Notable people with the surname "Wheat" include: Alan Wheat (born 1951), American politician Alfred Adams Wheat, American judge Arthur Wheat (disambiguation), multiple people Bill Wheat, American politician Brian Wheat (born 1963), American musician Carl Irving Wheat, American cart... | {
"page_id": 40573523,
"title": "Wheat (surname)"
} |
The molecular formula C5H6N2 may refer to: Aminopyridines 2-Aminopyridine 3-Aminopyridine 4-Aminopyridine Diazepines 1,2-Diazepine 1,3-Diazepine 1,4-Diazepine Glutaronitrile Imidazole-4-acetaldehyde 1-Vinylimidazole | {
"page_id": 12261976,
"title": "C5H6N2"
} |
Chlorobenzonitrile may refer to: 2-Chlorobenzonitrile 3-Chlorobenzonitrile 4-Chlorobenzonitrile 2,6-Dichlorobenzonitrile | {
"page_id": 69540446,
"title": "Chlorobenzonitrile"
} |
Magnetic resonance is a process by which a physical excitation (resonance) is set up via magnetism. This process was used to develop magnetic resonance imaging (MRI) and nuclear magnetic resonance spectroscopy (NMRS) technology. It is also being used to develop nuclear magnetic resonance quantum computers. == History =... | {
"page_id": 203359,
"title": "Magnetic resonance"
} |
In chemistry, the term substrate is highly context-dependent. Broadly speaking, it can refer either to a chemical species being observed in a chemical reaction, or to a surface on which other chemical reactions or microscopy are performed. In the former sense, a reagent is added to the substrate to generate a product t... | {
"page_id": 8526433,
"title": "Substrate (chemistry)"
} |
to refer to the sample itself, rather than the solid support on which it is placed. == Spectroscopy == Various spectroscopic techniques also require samples to be mounted on substrates, such as powder diffraction. This type of diffraction, which involves directing high-powered X-rays at powder samples to deduce crystal... | {
"page_id": 8526433,
"title": "Substrate (chemistry)"
} |
the active site, before reacting together to produce products. A substrate is called 'chromogenic' if it gives rise to a coloured product when acted on by an enzyme. In histological enzyme localization studies, the colored product of enzyme action can be viewed under a microscope, in thin sections of biological tissues... | {
"page_id": 8526433,
"title": "Substrate (chemistry)"
} |
p450s) or it may have a single native substrate with a set of similar non-native substrates that it can catalyse at some lower rate. The substrates that a given enzyme may react with in vitro, in a laboratory setting, may not necessarily reflect the physiological, endogenous substrates of the enzyme's reactions in vivo... | {
"page_id": 8526433,
"title": "Substrate (chemistry)"
} |
The Ty5 is a type of retrotransposon native to the Saccharomyces cerevisiae organism. == The Saccharomyces cerevisiae retrotransposon Ty5 == Ty5 is one of five endogenous retrotransposons native to the model organism Saccharomyces cerevisiae, all of which target integration to gene poor regions. Endogenous retrotranspo... | {
"page_id": 7805539,
"title": "Ty5 retrotransposon"
} |
proteins that also include Sir1p, Sir2p and Sir3p. Of these, Sir2p, Sir3p and Sir4p form the core of heterochromatin. Sir4p serves as a binding site for Sir2p, which is the next to bind. Sir2p deacetylates adjacent histones, which is thought to further condense the chromatin and prevent the binding of other transcripti... | {
"page_id": 7805539,
"title": "Ty5 retrotransposon"
} |
Eric Findlay Bell is the Arthur F. Thurnau Professor of Astronomy at the University of Michigan. Formerly a staff scientist at the Max Planck Institute for Astronomy, Bell was a 2007 awardee of the Heinz Maier-Leibnitz-Prize from the German Research Foundation for his work on galaxy formation. He was part of the team t... | {
"page_id": 79895139,
"title": "Eric F. Bell"
} |
Carbon filtering is a method of filtering that uses a bed of activated carbon to remove impurities from a fluid using adsorption. == Mechanism == Carbon filtering works by adsorption, in which pollutants in the fluid to be treated are trapped inside the pore structure of a carbon substrate. The substrate is made of man... | {
"page_id": 3349094,
"title": "Carbon filtering"
} |
filter depends not only on its particle size, but also on the rate of flow of fluid through the filter. For example, if a fluid is allowed to flow through the filter at a slower rate, the contaminants will be exposed to the filter media for a longer amount of time, which will tend to result in fewer impurities. == See ... | {
"page_id": 3349094,
"title": "Carbon filtering"
} |
The molecular formula C5H7N3O2 (molar mass: 141.13 g/mol, exact mass: 141.0538 u) may refer to: dimetridazole 5-Hydroxymethylcytosine (5hmC) | {
"page_id": 12261991,
"title": "C5H7N3O2"
} |
Electron transfer (ET) occurs when an electron relocates from an atom, ion, or molecule, to another such chemical entity. ET describes the mechanism by which electrons are transferred in redox reactions. Electrochemical processes are ET reactions. ET reactions are relevant to photosynthesis and respiration and commonly... | {
"page_id": 2103914,
"title": "Electron transfer"
} |
suitable bridging ligand. A key concept of Marcus theory is that the rates of such self-exchange reactions are mathematically related to the rates of "cross reactions". Cross reactions entail partners that differ by more than their oxidation states. One example (of many thousands) is the reduction of permanganate by io... | {
"page_id": 2103914,
"title": "Electron transfer"
} |
transfer by Noel Hush and Marcus. The resultant theory, Marcus-Hush theory, has guided most discussions of electron transfer ever since. Both theories are, however, semiclassical in nature, although they have been extended to fully quantum mechanical treatments by Joshua Jortner, Alexander M. Kuznetsov, and others proc... | {
"page_id": 2103914,
"title": "Electron transfer"
} |
A cistron is a region of DNA that is conceptually equivalent to some definitions of a gene, such that the terms are synonymous from certain viewpoints, especially with regard to the molecular gene as contrasted with the Mendelian gene. The question of which scope of a subset of DNA (that is, how large a segment of DNA)... | {
"page_id": 6763,
"title": "Cistron"
} |
selection. He also defines replicators, more general than cistrons and genes, in this gene-centered view of evolution. == Definition == Defining a Cistron as a segment of DNA coding for a polypeptide, the structural gene in a transcription unit could be said as monocistronic (mostly in eukaryotes) or polycistronic (mos... | {
"page_id": 6763,
"title": "Cistron"
} |
Polyimide foam is a foam originally designed for NASA by Inspec Foams Inc. under the brand name Solimide. Its primary purposes are as an insulator (such as for rocket fuels) and acoustic damper. NASA engineered the product to have relatively low outgassing (a problem in vacuum and aboard spacecraft), desirable thermal ... | {
"page_id": 7346797,
"title": "Polyimide foam"
} |
Transcription factor II F (TFIIF) is one of several general transcription factors that make up the RNA polymerase II preinitiation complex. TFIIF is encoded by the GTF2F1, GTF2F2, and GTF2F2L genes. TFIIF binds to RNA polymerase II when the enzyme is already unbound to any other transcription factor, thus preventing it... | {
"page_id": 12589679,
"title": "Transcription factor II F"
} |
Carcinoembryonic antigen peptide-1 is a nine amino acid peptide fragment of carcinoembryonic antigen (CEA), a protein that is overexpressed in several cancer cell types, including gastrointestinal, breast, and non-small-cell lung. Synonyms: CAP-1 Carcinoembryonic Antigen Peptide-1 Carcinoembryonic Peptide-1 CEA Peptide... | {
"page_id": 14359155,
"title": "Carcinoembryonic antigen peptide-1"
} |
The molecular formula C5H8O (molar mass: 84.12 g/mol) may refer to: Cyclopentanone 2,3-Dihydropyran trans-2-Methyl-2-butenal 2-Methylbut-3-yn-2-ol 3-Penten-2-one | {
"page_id": 12262006,
"title": "C5H8O"
} |
This is a list of past and current experiments at the CERN Proton Synchrotron (PS) facility since its commissioning in 1959. The PS was CERN's first synchrotron and the world's highest energy particle accelerator at the time. It served as the flagship of CERN until the 1980s when its main role became to provide injecti... | {
"page_id": 55188089,
"title": "List of Proton Synchrotron experiments"
} |
Odell Down Under is a 1994 game for Microsoft Windows and Classic Mac OS that takes place in the Great Barrier Reef of Australia. Released by MECC, it is the sequel to Odell Lake. == History == Odell Down Under was released alongside a re-release of its companion game, Odell Lake. The game was recommended for ages 9 to... | {
"page_id": 3938944,
"title": "Odell Down Under"
} |
next fish, the player's fish has to find enough food (which can include plants, crustaceans or coral as well as fish) to prevent its constantly decreasing energy bar from reaching 0 and death. The other main concern, besides avoiding predators, is health, which can only be repaired by finding a bluestreak cleaner wrass... | {
"page_id": 3938944,
"title": "Odell Down Under"
} |
The decay energy is the energy change of a nucleus having undergone a radioactive decay. Radioactive decay is the process in which an unstable atomic nucleus loses energy by emitting ionizing particles and radiation. This decay, or loss of energy, results in an atom of one type (called the parent nuclide) transforming ... | {
"page_id": 72325,
"title": "Decay energy"
} |
molar weight is 59.93. The half life T of 5.27 year corresponds to the activity A = N [ ln(2) / T ], where N is the number of atoms per mol, and T is the half-life. Taking care of the units the radiation power for 60Co is 17.9 W/g Radiation power in W/g for several isotopes: 60Co: 17.9 238Pu: 0.57 137Cs: 0.6 241Am: 0.1... | {
"page_id": 72325,
"title": "Decay energy"
} |
The Journal of Non-Equilibrium Thermodynamics is a quarterly peer-reviewed scientific journal covering the field of non-equilibrium thermodynamics. It was established in 1976 by Jurgen Keller and its current editor-in-chief is Karl-Heinz Hoffmann (Chemnitz University of Technology). == Abstracting and indexing == The j... | {
"page_id": 43326086,
"title": "Journal of Non-Equilibrium Thermodynamics"
} |
Decorrelation is a general term for any process that is used to reduce autocorrelation within a signal, or cross-correlation within a set of signals, while preserving other aspects of the signal. A frequently used method of decorrelation is the use of a matched linear filter to reduce the autocorrelation of a signal as... | {
"page_id": 5839494,
"title": "Decorrelation"
} |
many other fields. In neuroscience, decorrelation is used in the analysis of the neural networks in the human visual system. In cryptography, it is used in cipher design (see Decorrelation theory) and in the design of hardware random number generators. == See also == Equalisation Randomness extractor Eigenvalue decompo... | {
"page_id": 5839494,
"title": "Decorrelation"
} |
Commercially useful enzymes (CUEs) are enzymes with applications in various industries. Microbial enzymes are widely utilized as biocatalysts in fields such as biotechnology, agriculture, and pharmaceuticals. Metagenomic data serve as a valuable resource for identifying novel CUEs from previously unknown microbes prese... | {
"page_id": 11147912,
"title": "Commercially useful enzymes"
} |
Soil mesofauna are invertebrates between 0.1mm and 2mm in size, which live in the soil or in a leaf litter layer on the soil surface. Members of this group include nematodes, mites, springtails (collembola), proturans, pauropods, rotifers, earthworms, tardigrades, small spiders, pseudoscorpions, opiliones (harvestmen),... | {
"page_id": 35986059,
"title": "Soil mesofauna"
} |
is the organic horizon or O horizon, the area of accumulation of animal residues and recognizable plant material. Animal residues are higher in nitrogen than plant residues with respect to the total carbon in the residue. Some Nitrogen fixation is caused by bacteria which consume the amino acids and sugar that are exud... | {
"page_id": 35986059,
"title": "Soil mesofauna"
} |
A Faraday balance is a device used to measure magnetic susceptibility, a property of matter is related to the force experienced by a substance in a magnetic field. Various practical devices are available for the measurement of susceptibility, with differences in the shape of the field and the way the force is measured.... | {
"page_id": 30939788,
"title": "Faraday balance"
} |
Attention is a machine learning method that determines the importance of each component in a sequence relative to the other components in that sequence. In natural language processing, importance is represented by "soft" weights assigned to each word in a sentence. More generally, attention encodes vectors called token... | {
"page_id": 66001552,
"title": "Attention (machine learning)"
} |
items (the Key vectors of each word in the sentence). However, both Self and Cross Attentions' parallel calculations matches all tokens of the K matrix with all tokens of the Q matrix; therefore the roles of these vectors are symmetric. Possibly because the simplistic database analogy is flawed, much effort has gone in... | {
"page_id": 66001552,
"title": "Attention (machine learning)"
} |
consisting of a weighted sum of the hidden vectors, rather than "the best one", as there may not be a best hidden vector. == Variants == Many variants of attention implement soft weights, such as fast weight programmers, or fast weight controllers (1992). A "slow" neural network outputs the "fast" weights of another ne... | {
"page_id": 66001552,
"title": "Attention (machine learning)"
} |
attention algorithm. == Self-Attention and Transformers == The major breakthrough came with self-attention, where each element in the input sequence attends to all others, enabling the model to capture global dependencies. This idea was central to the Transformer architecture, which replaced recurrence entirely with at... | {
"page_id": 66001552,
"title": "Attention (machine learning)"
} |
{\displaystyle m} -by- d v {\displaystyle d_{v}} output matrix are confined to the convex hull of the points in R d v {\displaystyle \mathbb {R} ^{d_{v}}} given by the rows of V {\displaystyle \mathbf {V} } . To understand the permutation invariance and permutation equivariance properties of QKV attention, let A ∈ R m ... | {
"page_id": 66001552,
"title": "Attention (machine learning)"
} |
re-ordering the rows of the input matrix X {\displaystyle X} in a non-trivial way, because every row of the output is a function of all the rows of the input. Similar properties hold for multi-head attention, which is defined below. === Masked Attention === When QKV attention is used as a building block for an autoregr... | {
"page_id": 66001552,
"title": "Attention (machine learning)"
} |
W i K , V W i V ) {\displaystyle {\text{head}}_{i}={\text{Attention}}(\mathbf {Q} \mathbf {W} _{i}^{Q},\mathbf {K} \mathbf {W} _{i}^{K},\mathbf {V} \mathbf {W} _{i}^{V})} and W i Q , W i K , W i V {\displaystyle \mathbf {W} _{i}^{Q},\mathbf {W} _{i}^{K},\mathbf {W} _{i}^{V}} , and W O {\displaystyle \mathbf {W} ^{O}} a... | {
"page_id": 66001552,
"title": "Attention (machine learning)"
} |
same as cross-attention, except that query, key, and value vectors all come from the same model. Both encoder and decoder can use self-attention, but with subtle differences. For encoder self-attention, we can start with a simple encoder without self-attention, such as an "embedding layer", which simply converts each i... | {
"page_id": 66001552,
"title": "Attention (machine learning)"
} |
== Olah, Chris; Carter, Shan (September 8, 2016). "Attention and Augmented Recurrent Neural Networks". Distill. 1 (9). Distill Working Group. doi:10.23915/distill.00001. Dan Jurafsky and James H. Martin (2022) Speech and Language Processing (3rd ed. draft, January 2022), ch. 10.4 Attention and ch. 9.7 Self-Attention Ne... | {
"page_id": 66001552,
"title": "Attention (machine learning)"
} |
Arie Jacobus Johannes "Jack" Ooms (1925 - 6 September 1999, Spain) was a Dutch chemist, diplomat and chemical weapons researcher. As head of Dutch chemical defence research, Ooms worked for 23 years for the eradication of chemical warfare, which he believed could best be achieved by a combination of effective chemical ... | {
"page_id": 53746322,
"title": "Jack Ooms"
} |
on Disarmament (ENCD) in Geneva as a technical adviser. The ENCD (1962-1969) was one of several predecessors to the Conference on Disarmament (CD). Ooms became the only CD delegate that continuously participated over the full 20 years of negotiations, which culminated in the adoption of the Chemical Weapons Convention ... | {
"page_id": 53746322,
"title": "Jack Ooms"
} |
Separation and Purification Technology is a peer-reviewed scientific journal published by Elsevier, covering methods for separation and purification in chemical and environmental engineering, including research on the separation and purification of liquids, vapors, and gases, as well as carbon capture and separation, e... | {
"page_id": 77798037,
"title": "Separation and Purification Technology"
} |
The molecular formula C5H8O2 may refer to: Acetylacetone Acetylpropionyl Allyl acetate Angelic acid Coffee furanone Cyclobutanecarboxylic acid Ethyl acrylate Glutaraldehyde Isopropenyl acetate Methyl methacrylate Tiglic acid Valerolactones δ-Valerolactone γ-Valerolactone Vinyl propionate | {
"page_id": 12262038,
"title": "C5H8O2"
} |
In solid-state physics, Friedel oscillations, named after French physicist Jacques Friedel, arise from localized perturbations in a metallic or semiconductor system caused by a defect in the Fermi gas or Fermi liquid. Friedel oscillations are a quantum mechanical analog to electric charge screening of charged species i... | {
"page_id": 25631381,
"title": "Friedel oscillations"
} |
taken over all wave vectors less than the Fermi wave vector k F = 2 m E F / ℏ 2 {\displaystyle k_{\rm {F}}={\sqrt {2mE_{\rm {F}}/\hbar ^{2}}}} , the factor 2 accounts for the spin degeneracy. By transforming the sum over k {\displaystyle k} into the integral we obtain n ( x ) = 2 L π ∫ 0 k F | ψ k ( x ) | 2 d k = 2 k F... | {
"page_id": 25631381,
"title": "Friedel oscillations"
} |
up to a fixed energy level, the so-called Fermi energy. The radius of the sphere in k-space, kF, is called the Fermi wave vector. If there is a foreign atom embedded in the metal or semiconductor, a so-called impurity, the electrons that move freely through the solid are scattered by the deviating potential of the impu... | {
"page_id": 25631381,
"title": "Friedel oscillations"
} |
liquid. The fermions in the fluid that take part in the screening cannot be considered as a point entity but a wave-vector is required to describe them. Charge density away from the perturbation is not a continuum but fermions arrange themselves at discrete spaces away from the perturbation. This effect is the cause of... | {
"page_id": 25631381,
"title": "Friedel oscillations"
} |
Space-based solar power (SBSP or SSP) is the concept of collecting solar power in outer space with solar power satellites (SPS) and distributing it to Earth. Its advantages include a higher collection of energy due to the lack of reflection and absorption by the atmosphere, the possibility of very little night, and a b... | {
"page_id": 6757017,
"title": "Space-based solar power"
} |
the necessarily vast size of the receiving antennas would still require large blocks of land near the end users. The service life of space-based collectors in the face of long-term exposure to the space environment, including degradation from radiation and micrometeoroid damage, could also become a concern for SBSP. As... | {
"page_id": 6757017,
"title": "Space-based solar power"
} |
earth in 2023. == History == In 1941, science fiction writer Isaac Asimov published the science fiction short story "Reason", in which a space station transmits energy collected from the Sun to various planets using microwave beams. The SBSP concept, originally known as satellite solar-power system (SSPS), was first de... | {
"page_id": 6757017,
"title": "Space-based solar power"
} |
Beam Propagation and Direct Solar Pumped Lasers Public Outreach Experiment Power Transmission and Reception Technical Summary and Assessment Space Transportation ==== Discontinuation ==== The project was not continued with the change in administrations after the 1980 United States elections. The Office of Technology As... | {
"page_id": 6757017,
"title": "Space-based solar power"
} |
requirements. Create conceptual designs of subsystems that make use of advanced SSP technologies to benefit future space or terrestrial applications. Formulate a preliminary plan of action for the U.S. (working with international partners) to undertake an aggressive technology initiative. Construct technology developme... | {
"page_id": 6757017,
"title": "Space-based solar power"
} |
much lower cost access to space than has been available); however, the same can be said of many other advanced power technologies options. Space solar power may well emerge as a serious candidate among the options for meeting the energy demands of the 21st century. Launch costs in the range of $100–$200 per kilogram of... | {
"page_id": 6757017,
"title": "Space-based solar power"
} |
in space and full sun. Collecting surfaces could receive much more intense sunlight, owing to the lack of obstructions such as atmospheric gasses, clouds, dust and other weather events. Consequently, the intensity in orbit is approximately 144% of the maximum attainable intensity on Earth's surface. A satellite could b... | {
"page_id": 6757017,
"title": "Space-based solar power"
} |
optic requires gigawatt scale to compensate for Airy disk beam spreading. Typically a 1 km disk in geosynchronous orbit transmitting at 2.45 GHz spreads out to 10 km at Earth distance. Inability to constrain power transmission inside tiny beam angles. For example, a beam of 0.002 degrees (7.2 arc seconds) is required t... | {
"page_id": 6757017,
"title": "Space-based solar power"
} |
at a billion dollars for 5 GW by SBSP researcher Keith Henson. Energy losses during several phases of conversion from photons to electrons to photons back to electrons. Waste heat disposal in space power systems is difficult to begin with, but becomes intractable when the entire spacecraft is designed to absorb as much... | {
"page_id": 6757017,
"title": "Space-based solar power"
} |
antenna The space-based portion will not need to support itself against gravity (other than relatively weak tidal stresses). It needs no protection from terrestrial wind or weather, but will have to cope with space hazards such as micrometeors and solar flares. Two basic methods of conversion have been studied: photovo... | {
"page_id": 6757017,
"title": "Space-based solar power"
} |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.