Powder diffractionPowder diffraction is a scientific technique using X-ray, neutron, or electron diffraction on powder or microcrystalline samples for structural characterization of materials. An instrument dedicated to performing such powder measurements is called a powder diffractometer. Powder diffraction stands in contrast to single crystal diffraction techniques, which work best with a single, well-ordered crystal. Diffraction grating The most common type of powder diffraction is with x-rays, the focus of this article although some aspects of neutron powder diffraction are mentioned.
Crystallographic point groupIn crystallography, a crystallographic point group is a set of symmetry operations, corresponding to one of the point groups in three dimensions, such that each operation (perhaps followed by a translation) would leave the structure of a crystal unchanged i.e. the same kinds of atoms would be placed in similar positions as before the transformation.
Space groupIn mathematics, physics and chemistry, a space group is the symmetry group of a repeating pattern in space, usually in three dimensions. The elements of a space group (its symmetry operations) are the rigid transformations of the pattern that leave it unchanged. In three dimensions, space groups are classified into 219 distinct types, or 230 types if chiral copies are considered distinct. Space groups are discrete cocompact groups of isometries of an oriented Euclidean space in any number of dimensions.
X-ray scattering techniquesX-ray scattering techniques are a family of non-destructive analytical techniques which reveal information about the crystal structure, chemical composition, and physical properties of materials and thin films. These techniques are based on observing the scattered intensity of an X-ray beam hitting a sample as a function of incident and scattered angle, polarization, and wavelength or energy.
Budgie (desktop environment)Budgie is an independent, free and open-source desktop environment for Linux and other Unix-like operating systems that targets the desktop metaphor. Budgie is developed by the Buddies of Budgie organization, which is composed of a team of contributors from Linux distributions such as Fedora, Debian, and Arch Linux. Its design emphasizes simplicity, minimalism, and elegance, while providing the means to extend or customize the desktop in various ways.
Cinnamon (desktop environment)Cinnamon is a free and open-source desktop environment for Linux and Unix-like operating systems, deriving from GNOME 3 but following traditional desktop metaphor conventions. The development of Cinnamon began by the Linux Mint team as a reaction to the April 2011 release of GNOME 3 in which the conventional desktop metaphor of GNOME 2 was abandoned in favor of GNOME Shell. Following several attempts to extend GNOME 3 such that it would suit the Linux Mint design goals, the Mint developers forked several GNOME 3 components to build an independent desktop environment.
MATE (software)MATE (ˈmɑːtE) is a desktop environment composed of free and open-source software that runs on Linux, BSD, and illumos operating systems. MATE is named after the South American plant yerba mate and tea made from the herb, mate. The name is stylized in all capital letters to follow the nomenclature of other Free Software desktop environments like KDE and LXDE. The recursive backronym "MATE Advanced Traditional Environment" was subsequently adopted by most of the MATE community, again in the spirit of Free Software like GNU ("GNU's Not Unix!").
Share capitalA corporation's share capital, commonly referred to as capital stock in the United States, is the portion of a corporation's equity that has been derived by the issue of shares in the corporation to a shareholder, usually for cash. "Share capital" may also denote the number and types of shares that compose a corporation's share structure. In accounting, the share capital of a corporation is the nominal value of issued shares (that is, the sum of their par values, sometimes indicated on share certificates).
Structural analysisStructural analysis is a branch of solid mechanics which uses simplified models for solids like bars, beams and shells for engineering decision making. Its main objective is to determine the effect of loads on the physical structures and their components. In contrast to theory of elasticity, the models used in structure analysis are often differential equations in one spatial variable. Structures subject to this type of analysis include all that must withstand loads, such as buildings, bridges, aircraft and ships.
CrystalA crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macroscopic single crystals are usually identifiable by their geometrical shape, consisting of flat faces with specific, characteristic orientations. The scientific study of crystals and crystal formation is known as crystallography.
Wallpaper groupA wallpaper is a mathematical object covering a whole Euclidean plane by repeating a motif indefinitely, in manner that certain isometries keep the drawing unchanged. To a given wallpaper there corresponds a group of such congruent transformations, with function composition as the group operation. Thus, a wallpaper group (or plane symmetry group or plane crystallographic group) is in a mathematical classification of a two‐dimensional repetitive pattern, based on the symmetries in the pattern.
DiffractionDiffraction is the interference or bending of waves around the corners of an obstacle or through an aperture into the region of geometrical shadow of the obstacle/aperture. The diffracting object or aperture effectively becomes a secondary source of the propagating wave. Italian scientist Francesco Maria Grimaldi coined the word diffraction and was the first to record accurate observations of the phenomenon in 1660.
