B. Lefèvre-Feragen

	B. Lefèvre-Feragen B is the second letter of the Latin alphabet. B may also refer to: Science, technology, and mathematics Astronomy * Astronomical objects in the Barnard list of dark nebulae (abbreviation B) * Latitude (''b'') in the galactic coordinate system Biology and medicine * Haplogroup B (mtDNA), a human mitochondrial DNA (mtDNA) haplogroup * Haplogroup B (Y-DNA), a Y-chromosomal DNA (Y-DNA) haplogroup * Blood type B * ATC code B ''Blood and blood forming organs'', a section of the Anatomical Therapeutic Chemical Classification System * Vitamin B * Hepatitis B * Berlin Botanical Garden and Botanical Museum, assigned the abbreviation B as a repository of herbarium specimens Computing * B (programming language) * B-Method, for computer software development * B-tree, a data structure * Bit (b) * Byte (B) * , an HTML element denoting bold text Physical and chemical quantities and units * One of the reciprocal lattice vectors (''b'') Breadth (''b''); see length * Impact parameter (''b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	List Of Dark Nebulae This is a list of dark nebulae (absorption nebulae), also called "dark clouds". List * Finger of God Globule E Nebula (Barnard 142 and 143) Barnard 68, possibly the closest to Earth at about 400 light-years. Le Gentil 3 Sandqvist 111 Sandqvist 112 Sandqvist 150 Sandqvist 155 Sandqvist 157 Sandqvist 166 Sandqvist 169 Sandqvist 171 Sandqvist 178 Bernes 157 (Sandqvist and Lindroos, SL 39-41), another close dark nebula of the Corona Australis Molecular Cloud, which includes NGC 6729 SL 41 LDN 43 (Cosmic Bat Nebula) LDN 193 LDN 206 LDN 208 LDN 535 LDN 615 LDN 621 LDN 624 LDN 673 LDN 688 and LDN 687 LDN 695 LDN 749 LDN 762 LDN 763 and LDN 764 LDN 750 LDN 771 LDN 780 LDN 790 LDN 792 LDN 793 LDN 794 LDN 795 LDN 796 LDN 798 LDN 866 LDN 898 LDN 921 LDN 923 and LDN 924 LDN 925 LDN 930 LDN 935 LDN 940 LDN 950 LDN 954 LDN 958 LDN 972 LDN 1010 LDN 1020 LDN 1066 LDN 1073 LDN 1083 LDN 1105 LDN 1109 LDN 1139 LDN 1141 LDN 1142 LDN 115 ... [...More Info...] [...Related Items...] OR:* [Wikipedia] [Google] [Baidu]
	Molality In chemistry, molality is a measure of the amount of solute in a solution relative to a given mass of solvent. This contrasts with the definition of '' molarity'' which is based on a given volume of solution. A commonly used unit for molality is the moles per kilogram (mol/kg). A solution of concentration 1 mol/kg is also sometimes denoted as 1 molal. The unit mol/kg requires that molar mass be expressed in kg/mol, instead of the usual g/mol or kg/kmol. Definition The molality (''b''), of a solution is defined as the amount of substance (in moles) of solute, ''n''solute, divided by the mass (in kg) of the solvent, ''m''solvent: :b = \frac. In the case of solutions with more than one solvent, molality can be defined for the mixed solvent considered as a pure pseudo-solvent. Instead of mole solute per kilogram solvent as in the binary case, units are defined as mole solute per kilogram mixed solvent. Origin The term ''molality'' is formed in analogy to ''molari ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Boron Boron is a chemical element; it has symbol B and atomic number 5. In its crystalline form it is a brittle, dark, lustrous metalloid; in its amorphous form it is a brown powder. As the lightest element of the boron group it has three valence electrons for forming covalent bonds, resulting in many compounds such as boric acid, the mineral sodium borate, and the ultra-hard crystals of boron carbide and boron nitride. Boron is synthesized entirely by cosmic ray spallation and supernovas and not by stellar nucleosynthesis, so it is a low-abundance element in the Solar System and in the Earth's crust. It constitutes about 0.001 percent by weight of Earth's crust. It is concentrated on Earth by the water-solubility of its more common naturally occurring compounds, the borate minerals. These are mined industrially as evaporites, such as borax and kernite. The largest known deposits are in Turkey, the largest producer of boron minerals. Elemental boron is found in smal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Boolean Domain In mathematics and abstract algebra, a Boolean domain is a set consisting of exactly two elements whose interpretations include ''false'' and ''true''. In logic, mathematics and theoretical computer science, a Boolean domain is usually written as , or \mathbb. The algebraic structure that naturally builds on a Boolean domain is the Boolean algebra with two elements. The initial object in the category of bounded lattices is a Boolean domain. In computer science, a Boolean variable is a variable that takes values in some Boolean domain. Some programming languages feature reserved words or symbols for the elements of the Boolean domain, for example false and true. However, many programming languages do not have a Boolean data type in the strict sense. In C or BASIC, for example, falsity is represented by the number 0 and truth is represented by the number 1 or −1, and all variables that can take these values can also take any other numerical values. Generalizations Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	B Meson In particle physics, B mesons are mesons composed of a bottom antiquark and either an up (), down (), strange () or charm quark (). The combination of a bottom antiquark and a top quark is not thought to be possible because of the top quark's short lifetime. The combination of a bottom antiquark and a bottom quark is not a B meson, but rather '' bottomonium'', which is something else entirely. Each B meson has an antiparticle that is composed of a bottom quark and an up (), down (), strange () or charm () antiquark respectively. List of B mesons – oscillations The neutral B mesons, and , spontaneously transform into their own antiparticles and back. This phenomenon is called flavor oscillation. The existence of neutral B meson oscillations is a fundamental prediction of the Standard Model of particle physics. It has been measured in the – system to be about , and in the – system to be measured by CDF experiment at Fermilab. A first estimation of the lower an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Elementary Particle In particle physics, an elementary particle or fundamental particle is a subatomic particle that is not composed of other particles. The Standard Model presently recognizes seventeen distinct particles—twelve fermions and five bosons. As a consequence of flavor and color combinations and antimatter, the fermions and bosons are known to have 48 and 13 variations, respectively. Among the 61 elementary particles embraced by the Standard Model number: electrons and other leptons, quarks, and the fundamental bosons. Subatomic particles such as protons or neutrons, which contain two or more elementary particles, are known as composite particles. Ordinary matter is composed of atoms, themselves once thought to be indivisible elementary particles. The name ''atom'' comes from the Ancient Greek word ''ἄτομος'' ( atomos) which means ''indivisible'' or ''uncuttable''. Despite the theories about atoms that had existed for thousands of years, the factual existence of ato ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]