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Beevers–Lipson Strip
Beevers–Lipson strips were a computational aid for early crystallographers in calculating Fourier transforms to determine the structure of crystals from crystallographic data, enabling the creation of models for complex molecules. They were used from the 1930s until computers with enough power became generally available in the 1960s. The technique was developed by C. Arnold Beevers (1908–2001), reader in crystallography at the University of Edinburgh, and Henry Lipson CBE FRS (1910–1991), Professor of Physics at the University of Manchester Institute of Science and Technology. The approach converted the sizable calculations of multi-dimensional Fourier summations needed in crystallography analysis into sums of more manageable one-dimensional values. The folded card strips with numbers were typically stored in two wooden boxes, one for sines and one for cosines. Previously it was necessary to consult sine/cosine tables, a time-consuming process. The approach was used by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sine
In mathematics, sine and cosine are trigonometric functions of an angle. The sine and cosine of an acute angle are defined in the context of a right triangle: for the specified angle, its sine is the ratio of the length of the side that is opposite that angle to the length of the longest side of the triangle (the hypotenuse), and the cosine is the ratio of the length of the adjacent leg to that of the hypotenuse. For an angle \theta, the sine and cosine functions are denoted simply as \sin \theta and \cos \theta. More generally, the definitions of sine and cosine can be extended to any real value in terms of the lengths of certain line segments in a unit circle. More modern definitions express the sine and cosine as infinite series, or as the solutions of certain differential equations, allowing their extension to arbitrary positive and negative values and even to complex numbers. The sine and cosine functions are commonly used to model periodic phenomena such as sound and lig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
History Of Chemistry
The history of chemistry represents a time span from ancient history to the present. By 1000 BC, civilizations used technologies that would eventually form the basis of the various branches of chemistry. Examples include the discovery of fire, extracting metals from ores, making pottery and glazes, fermenting beer and wine, extracting chemicals from plants for medicine and perfume, rendering fat into soap, making glass, and making alloys like bronze. The protoscience of chemistry, alchemy, was unsuccessful in explaining the nature of matter and its transformations. However, by performing experiments and recording the results, alchemists set the stage for modern chemistry. While both alchemy and chemistry are concerned with matter and its transformations, chemists are seen as applying scientific method to their work. The history of chemistry is intertwined with the history of thermodynamics, especially through the work of Willard Gibbs. Ancient history Early humans A 100,000 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fourier Analysis
In mathematics, Fourier analysis () is the study of the way general functions may be represented or approximated by sums of simpler trigonometric functions. Fourier analysis grew from the study of Fourier series, and is named after Joseph Fourier, who showed that representing a function as a sum of trigonometric functions greatly simplifies the study of heat transfer. The subject of Fourier analysis encompasses a vast spectrum of mathematics. In the sciences and engineering, the process of decomposing a function into oscillatory components is often called Fourier analysis, while the operation of rebuilding the function from these pieces is known as Fourier synthesis. For example, determining what component frequencies are present in a musical note would involve computing the Fourier transform of a sampled musical note. One could then re-synthesize the same sound by including the frequency components as revealed in the Fourier analysis. In mathematics, the term ''Fourier ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mathematical Tools
Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes. These topics are represented in modern mathematics with the major subdisciplines of number theory, algebra, geometry, and analysis, respectively. There is no general consensus among mathematicians about a common definition for their academic discipline. Most mathematical activity involves the discovery of properties of abstract objects and the use of pure reason to prove them. These objects consist of either abstractions from nature orin modern mathematicsentities that are stipulated to have certain properties, called axioms. A ''proof'' consists of a succession of applications of deductive rules to already established results. These results include previously proved theorems, axioms, andin case of abstraction from naturesome basic properties that are considered true starting points of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X-ray Crystallography
X-ray crystallography is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions. By measuring the angles and intensities of these diffracted beams, a crystallographer can produce a three-dimensional picture of the density of electrons within the crystal. From this electron density, the mean positions of the atoms in the crystal can be determined, as well as their chemical bonds, their crystallographic disorder, and various other information. Since many materials can form crystals—such as salts, metals, minerals, semiconductors, as well as various inorganic, organic, and biological molecules—X-ray crystallography has been fundamental in the development of many scientific fields. In its first decades of use, this method determined the size of atoms, the lengths and types of chemical bonds, and the atomic-scale differences among various mat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johns Hopkins University Press
The Johns Hopkins University Press (also referred to as JHU Press or JHUP) is the publishing division of Johns Hopkins University. It was founded in 1878 and is the oldest continuously running university press in the United States. The press publishes books and journals, and operates other divisions including fulfillment and electronic databases. Its headquarters are in Charles Village, Baltimore. In 2017, after the retirement of Kathleen Keane who is credited with modernizing JHU Press for the digital age, the university appointed new director Barbara Pope. Overview Daniel Coit Gilman, the first president of the Johns Hopkins University, inaugurated the press in 1878. The press began as the university's Publication Agency, publishing the ''American Journal of Mathematics'' in its first year and the ''American Chemical Journal'' in its second. It published its first book, ''Sidney Lanier: A Memorial Tribute'', in 1881 to honor the poet who was one of the university's first writers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elsevier
Elsevier () is a Dutch academic publishing company specializing in scientific, technical, and medical content. Its products include journals such as ''The Lancet'', ''Cell'', the ScienceDirect collection of electronic journals, '' Trends'', the '' Current Opinion'' series, the online citation database Scopus, the SciVal tool for measuring research performance, the ClinicalKey search engine for clinicians, and the ClinicalPath evidence-based cancer care service. Elsevier's products and services also include digital tools for data management, instruction, research analytics and assessment. Elsevier is part of the RELX Group (known until 2015 as Reed Elsevier), a publicly traded company. According to RELX reports, in 2021 Elsevier published more than 600,000 articles annually in over 2,700 journals; as of 2018 its archives contained over 17 million documents and 40,000 e-books, with over one billion annual downloads. Researchers have criticized Elsevier for its high profit marg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dorothy Hodgkin
Dorothy Mary Crowfoot Hodgkin (née Crowfoot; 12 May 1910 – 29 July 1994) was a Nobel Prize-winning British chemist who advanced the technique of X-ray crystallography to determine the structure of biomolecules, which became essential for structural biology. Among her most influential discoveries are the confirmation of the structure of penicillin as previously surmised by Edward Abraham and Ernst Boris Chain; and the structure of vitamin B12, for which in 1964 she became the third woman to win the Nobel Prize in Chemistry. Hodgkin also elucidated the structure of insulin in 1969 after 35 years of work. Hodgkin used the name "Dorothy Crowfoot" until twelve years after marrying Thomas Lionel Hodgkin, when she began using "Dorothy Crowfoot Hodgkin". Hodgkin is referred to as "Dorothy Hodgkin" by the Royal Society (when referring to its sponsorship of the Dorothy Hodgkin fellowship), and by Somerville College. The National Archives of the United Kingdom refer to her as " ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nobel Prize
The Nobel Prizes ( ; sv, Nobelpriset ; no, Nobelprisen ) are five separate prizes that, according to Alfred Nobel's will of 1895, are awarded to "those who, during the preceding year, have conferred the greatest benefit to humankind." Alfred Nobel was a Swedish chemist, engineer, and industrialist most famously known for the invention of dynamite. He died in 1896. In his will, he bequeathed all of his "remaining realisable assets" to be used to establish five prizes which became known as "Nobel Prizes." Nobel Prizes were first awarded in 1901. Nobel Prizes are awarded in the fields of Physics, Chemistry, Physiology or Medicine, Literature, and Peace (Nobel characterized the Peace Prize as "to the person who has done the most or best to advance fellowship among nations, the abolition or reduction of standing armies, and the establishment and promotion of peace congresses"). In 1968, Sveriges Riksbank (Sweden's central bank) funded the establishment of the Prize in Economi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Museum Of The History Of Science
The History of Science Museum in Broad Street, Oxford, England, holds a leading collection of scientific instruments from Middle Ages to the 19th century. The museum building is also known as the Old Ashmolean Building to distinguish it from the newer Ashmolean Museum building completed in 1894. The museum was built in 1683, and it is the world's oldest surviving purpose-built museum. History Built in 1683 to house Elias Ashmole's collection, the building was the world's first purpose-built museum building and was also open to the public. The original concept of the museum was to institutionalize the new learning about nature that appeared in the 17th century and experiments concerning natural philosophy were undertaken in a chemical laboratory in the basement, while lectures and demonstration took place in the School of Natural History, on the middle floor. Ashmole's collection was expanded to include a broad range of activities associated with the history of natural knowledge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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