|
Raymond E. Zirkle
Raymond Elliot Zirkle (January 9, 1902 – March 4, 1988) was an American biologist who was a pioneer in the field of radiation biology, and served as director of the Institute of Radio-Biology and Biophysics at the University of Chicago, Damon Runyon Fellow. Zirkle was elected to the National Academy of Sciences in 1959. Biography Early life and education Raymond Elliott Zirkle was born January 9, 1902, in Springfield, Illinois. His childhood was spent in northern Oklahoma and southern Missouri. He attended West Plains High School in West Plains, Missouri. After graduating high school he joined the Missouri National Guard and in 1924 married Mary Evelyn Ramsey. They went on to have two children together. Zirkle attended the University of Missouri and received a bachelor's degree in 1928 and a Ph.D. in 1932. His doctoral research involved irradiating spores of the fern ''Pteris longifolia'' with alpha particles from a polonium source''.'' Career Zirkle th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Springfield, Illinois
Springfield is the capital of the U.S. state of Illinois and the county seat and largest city of Sangamon County. The city's population was 114,394 at the 2020 census, which makes it the state's seventh most-populous city, the second largest outside of the Chicago metropolitan area (after Rockford), and the largest in central Illinois. Approximately 208,000 residents live in the Springfield metropolitan area. Springfield was settled by European-Americans in the late 1810s, around the time Illinois became a state. The most famous historic resident was Abraham Lincoln, who lived in Springfield from 1837 until 1861, when he went to the White House as President of the United States. Major tourist attractions include multiple sites connected with Lincoln including the Abraham Lincoln Presidential Library and Museum, Lincoln Home National Historic Site, Lincoln-Herndon Law Offices State Historic Site, and the Lincoln Tomb at Oak Ridge Cemetery. Springfield lies in a valley and pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Missouri National Guard
The Missouri National Guard (MONG), commonly known as the Missouri Guard, is a component of the Army National Guard and Missouri State Department of the National Guard. It is composed of Army and Air National Guard units. The Department office is located in Jefferson City. The Mission of the Missouri National Guard is "to provide trained and disciplined forces for domestic emergencies or as otherwise required by state law under the authority of the governor.” History The Missouri National Guard traces its origins to the Missouri State Militia, which was federally funded state militia conceived in 1861 and called to service in 1862 during the Civil War. It was a force designed to protect Missouri from Confederate guerillas. The Missouri Army National Guard was formed in 1877. It was first mobilized en-masse during the Spanish-American War in 1898. During the war, it was split into six volunteer infantry regiments. The 1st Missouri Infantry Regiment was commanded by Col. E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gamma Radiation
A gamma ray, also known as gamma radiation (symbol γ or \gamma), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves, typically shorter than those of X-rays. With frequencies above 30 exahertz (), it imparts the highest photon energy. Paul Villard, a French chemist and physicist, discovered gamma radiation in 1900 while studying radiation emitted by radium. In 1903, Ernest Rutherford named this radiation ''gamma rays'' based on their relatively strong penetration of matter; in 1900 he had already named two less penetrating types of decay radiation (discovered by Henri Becquerel) alpha rays and beta rays in ascending order of penetrating power. Gamma rays from radioactive decay are in the energy range from a few kiloelectronvolts (keV) to approximately 8 megaelectronvolts (MeV), corresponding to the typical energy levels in nuclei with reasonably long lifeti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manhattan Project
The Manhattan Project was a research and development undertaking during World War II that produced the first nuclear weapons. It was led by the United States with the support of the United Kingdom and Canada. From 1942 to 1946, the project was under the direction of Major General Leslie Groves of the United States Army Corps of Engineers, U.S. Army Corps of Engineers. Nuclear physicist Robert Oppenheimer was the director of the Los Alamos Laboratory that designed the actual bombs. The Army component of the project was designated the Manhattan District as its first headquarters were in Manhattan; the placename gradually superseded the official codename, Development of Substitute Materials, for the entire project. Along the way, the project absorbed its earlier British counterpart, Tube Alloys. The Manhattan Project began modestly in 1939, but grew to employ more than 130,000 people and cost nearly US$2 billion (equivalent to about $ billion in ). Over 90 percent of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indiana University
Indiana University (IU) is a system of public universities in the U.S. state of Indiana. Campuses Indiana University has two core campuses, five regional campuses, and two regional centers under the administration of IUPUI. *Indiana University Bloomington (IU Bloomington) is the flagship campus of Indiana University. The Bloomington campus is home to numerous premier Indiana University schools, including the College of Arts and Sciences, the Jacobs School of Music, an extension of the Indiana University School of Medicine, the School of Informatics, Computing, and Engineering, which includes the former School of Library and Information Science (now Department of Library and Information Science), School of Optometry, the O'Neil School of Public and Environmental Affairs, the Maurer School of Law, the School of Education, and the Kelley School of Business. *Indiana University–Purdue University Indianapolis (IUPUI), a partnership between Indiana University and Purdue Universi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha Radiation
Alpha decay or α-decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle (helium nucleus) and thereby transforms or 'decays' into a different atomic nucleus, with a mass number that is reduced by four and an atomic number that is reduced by two. An alpha particle is identical to the nucleus of a helium-4 atom, which consists of two protons and two neutrons. It has a charge of and a mass of . For example, uranium-238 decays to form thorium-234. While alpha particles have a charge , this is not usually shown because a nuclear equation describes a nuclear reaction without considering the electrons – a convention that does not imply that the nuclei necessarily occur in neutral atoms. Alpha decay typically occurs in the heaviest nuclides. Theoretically, it can occur only in nuclei somewhat heavier than nickel (element 28), where the overall binding energy per nucleon is no longer a maximum and the nuclides are therefore unstable toward spontaneo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radioactive Source
A radioactive source is a known quantity of a radionuclide which emits ionizing radiation; typically one or more of the radiation types gamma rays, alpha particles, beta particles, and neutron radiation. Sources can be used for irradiation, where the radiation performs a significant ionising function on a target material, or as a radiation metrology source, which is used for the calibration of radiometric process and radiation protection instrumentation. They are also used for industrial process measurements, such as thickness gauging in the paper and steel industries. Sources can be sealed in a container (highly penetrating radiation) or deposited on a surface (weakly penetrating radiation), or they can be in a fluid. As an irradiation source they are used in medicine for radiation therapy and in industry for such as industrial radiography, food irradiation, sterilization, vermin disinfestation, and irradiation crosslinking of PVC. Radionuclides are chosen according to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polonium
Polonium is a chemical element with the symbol Po and atomic number 84. Polonium is a chalcogen. A rare and highly radioactive metal with no stable isotopes, polonium is chemically similar to selenium and tellurium, though its metallic character resembles that of its horizontal neighbors in the periodic table: thallium, lead, and bismuth. Due to the short half-life of all its isotopes, its natural occurrence is limited to tiny traces of the fleeting polonium-210 (with a half-life of 138 days) in uranium ores, as it is the penultimate daughter of natural uranium-238. Though slightly longer-lived isotopes exist, they are much more difficult to produce. Today, polonium is usually produced in milligram quantities by the neutron irradiation of bismuth. Due to its intense radioactivity, which results in the radiolysis of chemical bonds and radioactive self-heating, its chemistry has mostly been investigated on the trace scale only. Polonium was discovered in July 1898 by Marie Sk ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha Particle
Alpha particles, also called alpha rays or alpha radiation, consist of two protons and two neutrons bound together into a particle identical to a helium-4 nucleus. They are generally produced in the process of alpha decay, but may also be produced in other ways. Alpha particles are named after the first letter in the Greek alphabet, α. The symbol for the alpha particle is α or α2+. Because they are identical to helium nuclei, they are also sometimes written as or indicating a helium ion with a +2 charge (missing its two electrons). Once the ion gains electrons from its environment, the alpha particle becomes a normal (electrically neutral) helium atom . Alpha particles have a net spin of zero. Due to the mechanism of their production in standard alpha radioactive decay, alpha particles generally have a kinetic energy of about 5 MeV, and a velocity in the vicinity of 4% of the speed of light. (See discussion below for the limits of these figures in alpha decay.) They are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pteris Longifolia
''Pteris longifolia'', the longleaf brake is a species of fern in the Pteridoideae ''Pteridoideae'' is one of the five subfamilies of the fern family Pteridaceae. This subfamily contains about 14 genera and around 400 species. Taxonomy Phylogeny The following diagram shows a likely phylogenic relationship between Pteridoideae ... subfamily of the Pteridaceae. References longifolia Plants described in 1753 Taxa named by Carl Linnaeus {{Pteridaceae-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fern
A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes except the lycopods, and differ from mosses and other bryophytes by being vascular, i.e., having specialized tissues that conduct water and nutrients and in having life cycles in which the branched sporophyte is the dominant phase. Ferns have complex leaves called megaphylls, that are more complex than the microphylls of clubmosses. Most ferns are leptosporangiate ferns. They produce coiled fiddleheads that uncoil and expand into fronds. The group includes about 10,560 known extant species. Ferns are defined here in the broad sense, being all of the Polypodiopsida, comprising both the leptosporangiate (Polypodiidae) and eusporangiate ferns, the latter group including horsetails, whisk ferns, marattioid ferns, and ophioglossoid ferns. Ferns first ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fern Sports
Fern sports are plants that show marked change from the normal type or parent stock as a result of mutation. The term Morphotype is also used for any of a group of different types of individuals of the same species in a population. Fern fronds in sports are typically altered in several ways, such as the frond apex divided and pinnae similarly duplicated. Occurrence Soft Shield Fern ''Polystichum setiferum'', Lady Fern ''Athyrium filix-femina'' and Hart's Tongue Fern ''Asplenium scolopendrium'' are known to have around three hundred varieties or sports.Peter D. A. Boyd's Pteridomania Retrieved : 2011-07-22 Scaly Male Fern and Male Fern [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Radioactive Source")
