Civil Rights
Movements, leaders, victories and the continuing fight for equality.
q2K BHP
Black History Portal
THE BHP WIRE —
HIDDEN TRUTHS
What's New!
Explore the people, places, events, achievements, struggles and stories that shaped our journey.
Movements, leaders, victories and the continuing fight for equality.
Innovation, patents, science, technology and world-changing contributions.
Pioneers, champions, Negro Leagues, records, activism and excellence.
Meet the people whose lives, choices and achievements shaped the journey.
Black towns, communities, institutions and places where history happened.
Moments that changed communities, movements, institutions and the nation.
Wilmington, North Carolina once had a thriving Black middle class and an elected interracial government. In 1898 white supremacists used violence to overthrow that government, kill Black residents and drive many others from the city.
MORE →Reflects the personal views, recollections, and perspective of the author, Mike Davis.
This is a personal recollection on the Move fire on May 13, 1985
A diffractometer is a measuring instrument for analyzing the structure of a material from the scattering pattern produced when a beam of radiation or particles (such as X-rays or neutrons) interacts with it.[1]
A typical diffractometer consists of a source of radiation, a monochromator to choose the wavelength, slits to adjust the shape of the beam, a sample and a detector. In a more complicated apparatus, a goniometer can also be used for fine adjustment of the sample and the detector positions. When an area detector is used to monitor the diffracted radiation, a beamstop is usually needed to stop the intense primary beam that has not been diffracted by the sample, otherwise the detector might be damaged. Usually the beamstop can be completely impenetrable to the X-rays or it may be semitransparent. The use of a semitransparent beamstop allows the possibility to determine how much the sample absorbs the radiation using the intensity observed through the beamstop.
There are several types of X-ray diffractometer, depending on the research field (material sciences, powder diffraction, life sciences, structural biology, etc.) and the experimental environment, if it is a laboratory with its home X-ray source or a Synchrotron. In laboratory, diffractometers are usually an "all in one" equipment, including the diffractometer, the video microscope and the X-ray source. Plenty of companies manufacture "all in one" equipment for X-ray home laboratory, such as Rigaku, Malvern Panalytical, Thermo Fisher Scientific, Bruker, Anton Paar and many others.
There are fewer diffractometer manufacturers for synchrotrons, owing to few numbers of x-ray beamlines to equip and the need of solid expertise of the manufacturer. For material sciences, Huber diffractometers are widely known and, for structural biology, Arinax diffractometers are the reference. Nonetheless, due to few numbers of manufacturers, a large amount of synchrotron diffractometers are "homemade" diffractometers, realized by synchrotron engineering teams.
X-ray diffractometer instruments can be used for a variety of purposes including imaging crystal structures, phase determination, and identifying unfamiliar substances for use in crystallography, inspection, and pharmaceutical research for drug efficacy.[2] A novel use of x-ray diffraction involves studying the surface of Mars to determine if it ever supported life.[3]
| Key concepts |
|  | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Characterisation | ||||||||||||||
| Algorithms | ||||||||||||||
| Software | ||||||||||||||
| Databases | ||||||||||||||
| Journals | ||||||||||||||
| Awards | ||||||||||||||
| History | ||||||||||||||
| Organisation |
| |||||||||||||
Source: Wikipedia. Article content is retrieved live through the MediaWiki API.
A diffractometer is a measuring instrument for analyzing the structure of a material from the scattering pattern produced when a beam of radiation or particles (such as X-rays or neutrons) interacts with it.
Powder 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.
Echidnas are Australian egg-laying mammals also known as spiny anteaters. Echidna may also refer to: Echidna (mythology), monster in Greek mythology and eponym of the mammal (42355) Typhon I Echidna, the natural satellite of the asteroid 42355 Typhon ECHIDNA, high-resolution neutron powder diffractometer at Australia's research reactor OPAL Echidna (Re:Zero), a character in the light novel series Re:Zero − Starting Life in Another World Echidna, character in the video game The Bouncer Echidna (Devil May Cry), a demoness in the video game Devil May Cry 4 Echidna, the Denizen of the Land of Frost and Frogs and the Land of Rays and Frogs in the webcomic Homestuck
Crystallography is the branch of science devoted to the study of molecular and crystalline structure and properties. The word crystallography is derived from the Ancient Greek word κρύσταλλος (krústallos; "clear ice, rock-crystal"), and γράφειν (gráphein; "to write"). In July 2012, the United Nations recognised the importance of the science of crystallography by proclaiming 2014 the International Year of Crystallography. Crystallography is a broad topic, and many of its subareas, such as X-ray crystallography, are themselves important scientific topics. Crystallography ranges from the fundamentals of crystal structure to the mathematics of crystal geometry, including those that are not periodic or quasicrystals. At the atomic scale it can involve the use of X-ray diffraction to produce experimental data that the tools of X-ray crystallography can convert into detailed positions of atoms, and sometimes electron density. At larger scales it includes experimental tools such as orientational imaging to examine the relative orientations at the grain boundary in materials. Crystallography plays a key role in many areas of biology, chemistry, and physics, as well as in emerging developments in these fields.
Before the 1921 destruction of Tulsa’s Greenwood District, Black residents had created a remarkable center of business and community life. The district included stores, professional offices, entertainment venues and homes owned by Black citizens. Understanding Greenwood means learning what was built—not only what was burned.
MORE →The Greenwood District.
