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Hydrofuge
Ultrahydrophobic (or superhydrophobic) surfaces are highly hydrophobic, i.e., extremely difficult to wet. The contact angles of a water droplet on an ultrahydrophobic material exceed 150°. This is also referred to as the lotus effect, after the superhydrophobic leaves of the lotus plant. A droplet striking these kinds of surfaces can fully rebound like an elastic ball. Interactions of bouncing drops can be further reduced using special superhydrophobic surfaces that promote symmetry breaking, pancake bouncing or waterbowl bouncing. Theory In 1805, Thomas Young defined the contact angle ''θ'' by analysing the forces acting on a fluid droplet resting on a smooth solid surface surrounded by a gas. :\gamma_\ =\gamma_+\gamma_\cos where :\gamma_\ = Interfacial tension between the solid and gas :\gamma_\ = Interfacial tension between the solid and liquid :\gamma_\ = Interfacial tension between the liquid and gas ''θ'' can be measured using a contact angle goniometer. Wenzel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gerridae
The Gerridae are a family of insects in the order Hemiptera, commonly known as water striders, water skeeters, water scooters, water bugs, pond skaters, water skippers, or water skimmers. Consistent with the classification of the Gerridae as true bugs (i.e., suborder Heteroptera), gerrids have mouthparts evolved for piercing and sucking, and distinguish themselves by having the unusual ability to walk on water, making them pleuston (surface-living) animals. They are anatomically built to transfer their weight to be able to run on top of the water's surface. As a result, one could likely find water striders present in any pond, river, or lake. Over 1,700 species of gerrids have been described, 10% of them being marine. While 90% of the Gerridae are freshwater bugs, the oceanic '' Halobates'' makes the family quite exceptional among insects. The genus ''Halobates'' was first heavily studied between 1822 and 1883 when Buchanan-White collected several different species during th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aquatic Insect
Aquatic insects or water insects live some portion of their life cycle in the water. They feed in the same ways as other insects. Some ''diving'' insects, such as predatory diving beetles, can hunt for food underwater where land-living insects cannot compete. Breathing One problem that aquatic insects must overcome is how to get oxygen while they are under water. Almost all animals require a source of oxygen to live. Insects draw air into their bodies through spiracles, holes found along the sides of the abdomen. These spiracles are connected to tracheal tubes where oxygen can be absorbed. All aquatic insects have become adapted to their environment with the specialization of these structures ;Aquatic adaptations # Simple diffusion over a relatively thin integument # Temporary use of an air bubble # Extraction of oxygen from water using a plastron or blood gill # Storage of oxygen in hemoglobin molecules in hemolymph # Taking oxygen from surface via breathing tubes ( siph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanopin Film
Nanopin film is an experimental material in nanotechnology developed in 2005 with unusual superhydrophobic properties . A droplet of water makes contact with the surface of this film and forms an almost perfect sphere with a contact angle of 178 °. This happens because it is covered with nanoscale, topped-off pins or cones perpendicular to the surface. The surface is regarded as a composite material with mostly air and a small fraction constituted by the tops of the cones. When the contact angle of the cone material is sufficiently large, Cassie's law predicts large contact angle values for the composite. This particular nanopin film is produced with borosilicate glass. A solution of CoCl2•6H2O or cobalt chloride hexahydrate is heated at 60 °C for 24 hours in a chemical bath deposition to form a brucite type cobalt(II) hydroxide layer with composition :CoOH1.13Cl0.09(CO3)0.39.0.05H20 The top coating is provided by lauric acid in a separate step. A 3 square micrometer surface now ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bionics
Bionics or biologically inspired engineering is the application of biological methods and systems found in nature to the study and design of engineering systems and modern technology. The word ''bionic'', coined by Jack E. Steele in August 1958, is a portmanteau from ''biology'' and ''electronics'' that was popularized by the 1970s U.S. television series ''The Six Million Dollar Man'' and ''The Bionic Woman'', both based upon the novel ''Cyborg'' by Martin Caidin. All three stories feature humans given various superhuman powers by their electromechanical implants. According to proponents of bionic technology, the transfer of technology between lifeforms and manufactured objects is desirable because evolutionary pressure typically forces living organisms – fauna and flora – to become optimized and efficient. For example, dirt- and water-repellent paint (coating) developed from the observation that practically nothing sticks to the surface of the lotus flower plant (the lot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Activation Energy
In chemistry and physics, activation energy is the minimum amount of energy that must be provided for compounds to result in a chemical reaction. The activation energy (''E''a) of a reaction is measured in joules per mole (J/mol), kilojoules per mole (kJ/mol) or kilocalories per mole (kcal/mol). Activation energy can be thought of as the magnitude of the potential barrier (sometimes called the energy barrier) separating minima of the potential energy surface pertaining to the initial and final thermodynamic state. For a chemical reaction to proceed at a reasonable rate, the temperature of the system should be high enough such that there exists an appreciable number of molecules with translational energy equal to or greater than the activation energy. The term "activation energy" was introduced in 1889 by the Swedish scientist Svante Arrhenius. Other uses Although less commonly used, activation energy also applies to nuclear reactions and various other physical phenomena. Te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Langmuir (journal)
''Langmuir'' is a peer-reviewed scientific journal that was established in 1985 and is published by the American Chemical Society. It is the leading journal focusing on the science and application of systems and materials in which the interface dominates structure and function. Research areas covered include surface and colloid chemistry. The total number of citations in 2021 is 129,693 and the 2021 Impact Factor is 4.331. Langmuir publishes original research articles, invited feature articles, perspectives, and editorials. The title honors Irving Langmuir, winner of the 1932 Nobel Prize for Chemistry. The founding editor-in-chief was Arthur W. Adamson. Abstracting and indexing ''Langmuir'' is indexed in Chemical Abstracts Service, Scopus, EBSCOhost, British Library, PubMed PubMed is a free search engine accessing primarily the MEDLINE database of references and abstracts on life sciences and biomedical topics. The United States National Library of Medicine (NLM) at the N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dimer (chemistry)
A dimer () ('' di-'', "two" + ''-mer'', "parts") is an oligomer consisting of two monomers joined by bonds that can be either strong or weak, covalent or intermolecular. Dimers also have significant implications in polymer chemistry, inorganic chemistry, and biochemistry. The term ''homodimer'' is used when the two molecules are identical (e.g. A–A) and ''heterodimer'' when they are not (e.g. A–B). The reverse of dimerization is often called dissociation. When two oppositely charged ions associate into dimers, they are referred to as ''Bjerrum pairs'', after Niels Bjerrum. Noncovalent dimers Anhydrous carboxylic acids form dimers by hydrogen bonding of the acidic hydrogen and the carbonyl oxygen. For example, acetic acid forms a dimer in the gas phase, where the monomer units are held together by hydrogen bonds. Under special conditions, most OH-containing molecules form dimers, e.g. the water dimer. Excimers and exciplexes are excited structures with a short lifetime. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planta (journal)
''Planta'' is a monthly peer-reviewed scientific journal covering all areas of botany. It was established in 1925 and is published by Springer Science+Business Media. The editors-in-chief are Anastasios Melis (UC-Berkeley) and Dorothea Bartels ( Universitat Bonn). According to the ''Journal Citation Reports'', the journal has a 2012 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a scientometric index calculated by Clarivate that reflects the yearly mean number of citations of articles published in the last two years in a given journal, as i ... of 3.347. References External links * Botany journals Publications established in 1925 Springer Science+Business Media academic journals Monthly journals English-language journals {{botany-journal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrowetting
Electrowetting is the modification of the wetting properties of a surface (which is typically hydrophobic) with an applied electric field. History The electrowetting of mercury and other liquids on variably charged surfaces was probably first explained by Gabriel Lippmann in 1875 and was certainly observed much earlier. A. N. Frumkin used surface charge to change the shape of water drops in 1936. The term electrowetting was first introduced in 1981 by G. Beni and S. Hackwood to describe an effect proposed for designing a new type of display device for which they received a patent. The use of a "fluid transistor" in microfluidic circuits for manipulating chemical and biological fluids was first investigated by J. Brown in 1980 and later funded in 1984–1988 under NSF Grants 8760730 & 8822197, employing insulating dielectric and hydrophobic layer(s) (EWOD), immiscible fluids, DC or RF power; and mass arrays of miniature interleaved (saw tooth) electrodes with large or matching Indi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanotechnology
Nanotechnology, also shortened to nanotech, is the use of matter on an atomic, molecular, and supramolecular scale for industrial purposes. The earliest, widespread description of nanotechnology referred to the particular technological goal of precisely manipulating atoms and molecules for fabrication of macroscale products, also now referred to as molecular nanotechnology. A more generalized description of nanotechnology was subsequently established by the National Nanotechnology Initiative, which defined nanotechnology as the manipulation of matter with at least one dimension sized from 1 to 100 nanometers (nm). This definition reflects the fact that quantum mechanical effects are important at this quantum-realm scale, and so the definition shifted from a particular technological goal to a research category inclusive of all types of research and technologies that deal with the special properties of matter which occur below the given size threshold. It is therefore common to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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