|
Transition
Transition or transitional may refer to: Mathematics, science, and technology Biology * Transition (genetics), a point mutation that changes a purine nucleotide to another purine (A ↔ G) or a pyrimidine nucleotide to another pyrimidine (C ↔ T) * Transitional fossil, any fossilized remains of a lifeform that exhibits the characteristics of two distinct taxonomic groups * A phase during childbirth contractions during which the cervix completes its dilation Gender and sex * Gender transitioning, the process of changing one's gender presentation to accord with one's internal sense of one's gender – the idea of what it means to be a man or woman * Sex reassignment therapy, the physical aspect of a gender transition Physics * Phase transition, a transformation of the state of matter; for example, the change between a solid and a liquid, between liquid and gas or between gas and plasma * Quantum phase transition, a phase transformation between different quantum phases * Quantu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phase Transition
In chemistry, thermodynamics, and other related fields, a phase transition (or phase change) is the physical process of transition between one state of a medium and another. Commonly the term is used to refer to changes among the basic states of matter: solid, liquid, and gas, and in rare cases, plasma. A phase of a thermodynamic system and the states of matter have uniform physical properties. During a phase transition of a given medium, certain properties of the medium change as a result of the change of external conditions, such as temperature or pressure. This can be a discontinuous change; for example, a liquid may become gas upon heating to its boiling point, resulting in an abrupt change in volume. The identification of the external conditions at which a transformation occurs defines the phase transition point. Types of phase transition At the phase transition point for a substance, for instance the boiling point, the two phases involved - liquid and vapor, have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glass Transition
The glass–liquid transition, or glass transition, is the gradual and reversible transition in amorphous materials (or in amorphous regions within semicrystalline materials) from a hard and relatively brittle "glassy" state into a viscous or rubbery state as the temperature is increased. ISO 11357-2: Plastics – Differential scanning calorimetry – Part 2: Determination of glass transition temperature (1999). An amorphous solid that exhibits a glass transition is called a glass. The reverse transition, achieved by supercooling a viscous liquid into the glass state, is called vitrification. The glass-transition temperature ''T''g of a material characterizes the range of temperatures over which this glass transition occurs (as an experimental definition, typically marked as 100 s of relaxation time). It is always lower than the melting temperature, ''T''m, of the crystalline state of the material, if one exists. Hard plastics like polystyrene and poly(methyl methacrylate) ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transition Metal
In chemistry, a transition metal (or transition element) is a chemical element in the d-block of the periodic table (groups 3 to 12), though the elements of group 12 (and less often group 3) are sometimes excluded. They are the elements that can use d orbitals as valence orbitals to form chemical bonds. The lanthanide and actinide elements (the f-block) are called inner transition metals and are sometimes considered to be transition metals as well. Since they are metals, they are lustrous and have good electrical and thermal conductivity. Most (with the exception of group 11 and Group 12 element, group 12) are hard and strong, and have high melting and boiling temperatures. They form compounds in any of two or more different oxidation states and bind to a variety of ligands to form coordination complexes that are often coloured. They form many useful alloys and are often employed as catalysts in elemental form or in compounds such as coordination complexes and Surface prope ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transition Management (governance)
Transition management is a governance approach that aims to facilitate and accelerate sustainability transitions through a participatory process of visioning, learning and experimenting. In its application, transition management seeks to bring together multiple viewpoints and multiple approaches in a 'transition arena'. Participants are invited to structure their shared problems with the current system and develop shared visions and goals which are then tested for practicality through the use of experimentation, learning and reflexivity. The model is often discussed in reference to sustainable development and the possible use of the model as a method for change. Key principles to transition management as a form of governance: * seeks to widen participation by taking a multi-actor approach in order to encompass societal values and beliefs * takes a long-term perspective (between 1-3 generations) creating a basket of visions in which short-term objectives can be identified * focus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gender Transitioning
Gender transition is the process of changing one's gender presentation or sex characteristics to accord with one's internal sense of gender identity – the idea of what it means to be a man or a woman,Brown, M. L. & Rounsley, C. A. (1996) ''True Selves: Understanding Transsexualism – For Families, Friends, Coworkers, and Helping Professionals'' Jossey-Bass: San Francisco or to be non-binary or genderqueer. For transgender and transsexual people, this process commonly involves reassignment therapy (which may include hormone replacement therapy and sex reassignment surgery), with their gender identity being opposite that of their birth-assigned sex and gender. Transitioning might involve medical treatment, but it does not always involve it. Cross-dressers, drag queens, and drag kings tend not to transition, since their variant gender presentations are (usually) only adopted temporarily. Transition begins with a decision to transition, prompted by the feeling that one's g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transitional Fossil
A transitional fossil is any fossilized remains of a life form that exhibits traits common to both an ancestral group and its derived descendant group. This is especially important where the descendant group is sharply differentiated by gross anatomy and mode of living from the ancestral group. These fossils serve as a reminder that taxonomic divisions are human constructs that have been imposed in hindsight on a continuum of variation. Because of the incompleteness of the fossil record, there is usually no way to know exactly how close a transitional fossil is to the point of divergence. Therefore, it cannot be assumed that transitional fossils are direct ancestors of more recent groups, though they are frequently used as models for such ancestors. In 1859, when Charles Darwin's ''On the Origin of Species'' was first published, the fossil record was poorly known. Darwin described the perceived lack of transitional fossils as "the most obvious and gravest objection which can be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Phase Transition
In physics, a quantum phase transition (QPT) is a phase transition between different quantum phases (Phase (matter), phases of matter at absolute zero, zero temperature). Contrary to classical phase transitions, quantum phase transitions can only be accessed by varying a physical parameter—such as magnetic field or pressure—at absolute zero temperature. The transition describes an abrupt change in the ground state of a many-body system due to its quantum fluctuations. Such a quantum phase transition can be a second-order phase transition. Quantum phase transitions can also be represented by the topological fermion condensation quantum phase transition, see e.g. strongly correlated quantum spin liquid. In case of three dimensional Fermi liquid, this transition transforms the Fermi surface into a Fermi volume. Such a transition can be a first-order phase transition, for it transforms two dimensional structure (Fermi surface) into three dimensional. As a result, the topological ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transition (literary Journal)
''transition'' was an experimental literary journal that featured surrealist, expressionist, and Dada art and artists. It was founded in 1927 by Maria McDonald and her husband Eugene Jolas and published in Paris. They were later assisted by editors Elliot Paul (April 1927 – March 1928), Robert Sage (October 1927 – Fall 1928), and James Johnson Sweeney (June 1936 – May 1938). Origins The literary journal was intended as an outlet for experimental writing and featured modernist, surrealist and other linguistically innovative writing and also contributions by visual artists, critics, and political activists. It ran until spring 1938. A total of 27 issues were produced. It was distributed primarily through Shakespeare and Company, the Paris bookstore run by Sylvia Beach. While it originally almost exclusively featured poetic experimentalists, it later accepted contributions from sculptors, civil rights activists, carvers, critics, and cartoonists. Editors who joined t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transition State
In chemistry, the transition state of a chemical reaction is a particular configuration along the reaction coordinate. It is defined as the state corresponding to the highest potential energy along this reaction coordinate. It is often marked with the double dagger ‡ symbol. As an example, the transition state shown below occurs during the SN2 reaction of bromoethane with a hydroxide anion: The activated complex of a reaction can refer to either the transition state or to other states along the reaction coordinate between reactants and products, especially those close to the transition state. Peter Atkins and Julio de Paula, ''Physical Chemistry'' (8th ed., W.H. Freeman 2006), p.809 According to the transition state theory, once the reactants have passed through the transition state configuration, they always continue to form products. History of concept The concept of a transition state has been important in many theories of the rates at which chemical react ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transition (journal)
Transition or transitional may refer to: Mathematics, science, and technology Biology * Transition (genetics), a point mutation that changes a purine nucleotide to another purine (A ↔ G) or a pyrimidine nucleotide to another pyrimidine (C ↔ T) * Transitional fossil, any fossilized remains of a lifeform that exhibits the characteristics of two distinct taxonomic groups * A phase during childbirth contractions during which the cervix completes its dilation Gender and sex * Gender transitioning, the process of changing one's gender presentation to accord with one's internal sense of one's gender – the idea of what it means to be a man or woman * Sex reassignment therapy, the physical aspect of a gender transition Physics * Phase transition, a transformation of the state of matter; for example, the change between a solid and a liquid, between liquid and gas or between gas and plasma * Quantum phase transition, a phase transformation between different quantum phases * Quan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta Decay Transition
In nuclear physics, a beta decay transition is the change in state of an atomic nucleus undergoing beta decay. (β-decay) When undergoing beta decay, a nucleus emits a beta particle and a corresponding neutrino, transforming the original nuclide into one with the same mass, but differing charge. (an isobar) There are several types of beta decay transition. In a ''Fermi transition'', the spins of the two emitted particles are anti-parallel, for a combined spin S=0. As a result, the total angular momentum of the nucleus is unchanged by the transition. By contrast, in a ''Gamow-Teller'' transition, the spins of the two emitted particles are parallel, with total spin S=1, leading to a change in angular momentum between the initial and final states of the nucleus. The theoretical work in describing these transitions was done between 1934 and 1936 by George Gamow and Edward Teller at George Washington University. The weak interaction and beta decay β decay had been first describe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laminar–turbulent Transition
In fluid dynamics, the process of a laminar flow becoming turbulent is known as laminar–turbulent transition. The main parameter characterizing transition is the Reynolds number. Transition is often described as a process proceeding through a series of stages. "Transitional flow" can refer to transition in either direction, that is laminar–turbulent transitional or turbulent–laminar transitional flow. The process applies to any fluid flow, and is most often used in the context of boundary layers. History In 1883 Osborne Reynolds demonstrated the transition to turbulent flow in a classic experiment in which he examined the behaviour of water flow under different flow rates using a small jet of dyed water introduced into the centre of flow in a larger pipe. The larger pipe was glass, so the behaviour of the layer of dyed flow could be observed, and at the end of this pipe was a flow-control valve used to vary the water velocity inside the tube. When the velocity was lo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
