|
Pd-107
Naturally occurring palladium (46Pd) is composed of six stable isotopes, 102Pd, 104Pd, 105Pd, 106Pd, 108Pd, and 110Pd, although 102Pd and 110Pd are theoretically unstable. The most stable radioisotopes are 107Pd with a half-life of 6.5 million years, 103Pd with a half-life of 17 days, and 100Pd with a half-life of 3.63 days. Twenty-three other radioisotopes have been characterized with atomic weights ranging from 90.949 u (91Pd) to 128.96 u (129Pd). Most of these have half-lives that are less than a half an hour except 101Pd (half-life: 8.47 hours), 109Pd (half-life: 13.7 hours), and 112Pd (half-life: 21 hours). The primary decay mode before the most abundant stable isotope, 106Pd, is electron capture and the primary mode after is beta decay. The primary decay product before 106Pd is rhodium and the primary product after is silver. Radiogenic 107Ag is a decay product of 107Pd and was first discovered in the Santa Clara meteorite of 1978. The discoverers suggest that the coal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pd-107
Naturally occurring palladium (46Pd) is composed of six stable isotopes, 102Pd, 104Pd, 105Pd, 106Pd, 108Pd, and 110Pd, although 102Pd and 110Pd are theoretically unstable. The most stable radioisotopes are 107Pd with a half-life of 6.5 million years, 103Pd with a half-life of 17 days, and 100Pd with a half-life of 3.63 days. Twenty-three other radioisotopes have been characterized with atomic weights ranging from 90.949 u (91Pd) to 128.96 u (129Pd). Most of these have half-lives that are less than a half an hour except 101Pd (half-life: 8.47 hours), 109Pd (half-life: 13.7 hours), and 112Pd (half-life: 21 hours). The primary decay mode before the most abundant stable isotope, 106Pd, is electron capture and the primary mode after is beta decay. The primary decay product before 106Pd is rhodium and the primary product after is silver. Radiogenic 107Ag is a decay product of 107Pd and was first discovered in the Santa Clara meteorite of 1978. The discoverers suggest that the coal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pd-103
Naturally occurring palladium (46Pd) is composed of six stable isotopes, 102Pd, 104Pd, 105Pd, 106Pd, 108Pd, and 110Pd, although 102Pd and 110Pd are theoretically unstable. The most stable radioisotopes are 107Pd with a half-life of 6.5 million years, 103Pd with a half-life of 17 days, and 100Pd with a half-life of 3.63 days. Twenty-three other radioisotopes have been characterized with atomic weights ranging from 90.949 u (91Pd) to 128.96 u (129Pd). Most of these have half-lives that are less than a half an hour except 101Pd (half-life: 8.47 hours), 109Pd (half-life: 13.7 hours), and 112Pd (half-life: 21 hours). The primary decay mode before the most abundant stable isotope, 106Pd, is electron capture and the primary mode after is beta decay. The primary decay product before 106Pd is rhodium and the primary product after is silver. Radiogenic 107Ag is a decay product of 107Pd and was first discovered in the Santa Clara meteorite of 1978. The discoverers suggest that the coale ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palladium
Palladium is a chemical element with the symbol Pd and atomic number 46. It is a rare and lustrous silvery-white metal discovered in 1803 by the English chemist William Hyde Wollaston. He named it after the asteroid Pallas, which was itself named after the epithet of the Greek goddess Athena, acquired by her when she slew Pallas. Palladium, platinum, rhodium, ruthenium, iridium and osmium form a group of elements referred to as the platinum group metals (PGMs). They have similar chemical properties, but palladium has the lowest melting point and is the least dense of them. More than half the supply of palladium and its congener platinum is used in catalytic converters, which convert as much as 90% of the harmful gases in automobile exhaust (hydrocarbons, carbon monoxide, and nitrogen dioxide) into nontoxic substances (nitrogen, carbon dioxide and water vapor). Palladium is also used in electronics, dentistry, medicine, hydrogen purification, chemical applications, groun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar System
The Solar System Capitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar System" and "solar system" structures in theinaming guidelines document. The name is commonly rendered in lower case ('solar system'), as, for example, in the ''Oxford English Dictionary'' an''Merriam-Webster's 11th Collegiate Dictionary''. is the gravitationally bound system of the Sun and the objects that orbit it. It formed 4.6 billion years ago from the gravitational collapse of a giant interstellar molecular cloud. The vast majority (99.86%) of the system's mass is in the Sun, with most of the remaining mass contained in the planet Jupiter. The four inner system planets— Mercury, Venus, Earth and Mars—are terrestrial planets, being composed primarily of rock and metal. The four giant planets of the outer system are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prostate Cancer
Prostate cancer is cancer of the prostate. Prostate cancer is the second most common cancerous tumor worldwide and is the fifth leading cause of cancer-related mortality among men. The prostate is a gland in the male reproductive system that surrounds the urethra just below the bladder. It is located in the hypogastric region of the abdomen. To give an idea of where it is located, the bladder is superior to the prostate gland as shown in the image The rectum is posterior in perspective to the prostate gland and the ischial tuberosity of the pelvic bone is inferior. Only those who have male reproductive organs are able to get prostate cancer. Most prostate cancers are slow growing. Cancerous cells may spread to other areas of the body, particularly the bones and lymph nodes. It may initially cause no symptoms. In later stages, symptoms include pain or difficulty urinating, blood in the urine, or pain in the pelvis or back. Benign prostatic hyperplasia may produce similar sym ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radiation Therapy
Radiation therapy or radiotherapy, often abbreviated RT, RTx, or XRT, is a therapy using ionizing radiation, generally provided as part of cancer treatment to control or kill malignant cells and normally delivered by a linear accelerator. Radiation therapy may be curative in a number of types of cancer if they are localized to one area of the body. It may also be used as part of adjuvant therapy, to prevent tumor recurrence after surgery to remove a primary malignant tumor (for example, early stages of breast cancer). Radiation therapy is synergistic with chemotherapy, and has been used before, during, and after chemotherapy in susceptible cancers. The subspecialty of oncology concerned with radiotherapy is called radiation oncology. A physician who practices in this subspecialty is a radiation oncologist. Radiation therapy is commonly applied to the cancerous tumor because of its ability to control cell growth. Ionizing radiation works by damaging the DNA of cancerous tissue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Element
A chemical element is a species of atoms that have a given number of protons in their nuclei, including the pure substance consisting only of that species. Unlike chemical compounds, chemical elements cannot be broken down into simpler substances by any chemical reaction. The number of protons in the nucleus is the defining property of an element, and is referred to as its atomic number (represented by the symbol ''Z'') – all atoms with the same atomic number are atoms of the same element. Almost all of the baryonic matter of the universe is composed of chemical elements (among rare exceptions are neutron stars). When different elements undergo chemical reactions, atoms are rearranged into new compounds held together by chemical bonds. Only a minority of elements, such as silver and gold, are found uncombined as relatively pure native element minerals. Nearly all other naturally occurring elements occur in the Earth as compounds or mixtures. Air is primarily a mixture ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cosmogenic
Cosmogenic nuclides (or cosmogenic isotopes) are rare nuclides (isotopes) created when a high-energy cosmic ray interacts with the nucleus of an ''in situ'' Solar System atom, causing nucleons (protons and neutrons) to be expelled from the atom (see cosmic ray spallation). These nuclides are produced within Earth materials such as rocks or soil, in Earth's atmosphere, and in extraterrestrial items such as meteoroids. By measuring cosmogenic nuclides, scientists are able to gain insight into a range of geological and astronomical processes. There are both radioactive and stable cosmogenic nuclides. Some of these radionuclides are tritium, carbon-14 and phosphorus-32. Certain light (low atomic number) primordial nuclides (isotopes of lithium, beryllium and boron) are thought to have been created not only during the Big Bang, but also (and perhaps primarily) to have been made after the Big Bang, but before the condensation of the Solar System, by the process of cosmic ray spall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long-lived Fission Product
Long-lived fission products (LLFPs) are radioactive materials with a long half-life (more than 200,000 years) produced by nuclear fission of uranium and plutonium. Because of their persistent radiotoxicity it is necessary to isolate them from man and biosphere and to confine them in nuclear waste repositories for geological period of times. Evolution of radioactivity in nuclear waste Nuclear fission produces fission products, as well as actinides from nuclear fuel nuclei that capture neutrons but fail to fission, and activation products from neutron activation of reactor or environmental materials. Short-term The high short-term radioactivity of spent nuclear fuel is primarily from fission products with short half-life. The radioactivity in the fission product mixture is mostly short-lived isotopes such as 131I and 140Ba, after about four months 141Ce, 95Zr/95Nb and 89Sr take the largest share, while after about two or three years the largest share is taken by 144Ce/144 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fission Product
Nuclear fission products are the atomic fragments left after a large atomic nucleus undergoes nuclear fission. Typically, a large nucleus like that of uranium fissions by splitting into two smaller nuclei, along with a few neutrons, the release of heat energy (kinetic energy of the nuclei), and gamma rays. The two smaller nuclei are the ''fission products''. (See also Fission products (by element)). About 0.2% to 0.4% of fissions are ternary fissions, producing a third light nucleus such as helium-4 (90%) or tritium (7%). The fission products themselves are usually unstable and therefore radioactive. Due to being relatively neutron-rich for their atomic number, many of them quickly undergo beta decay. This releases additional energy in the form of beta particles, antineutrinos, and gamma rays. Thus, fission events normally result in beta and gamma radiation, even though this radiation is not produced directly by the fission event itself. The produced radionuclides have va ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spontaneous Fission
Spontaneous fission (SF) is a form of radioactive decay that is found only in very heavy chemical elements. The nuclear binding energy of the elements reaches its maximum at an atomic mass number of about 56 (e.g., iron-56); spontaneous breakdown into smaller nuclei and a few isolated nuclear particles becomes possible at greater atomic mass numbers. History By 1908, physicists understood that alpha decay involved ejection of helium nuclei from a decaying atom. Like cluster decay, alpha decay is not typically categorized as a process of fission. The first nuclear fission process discovered was fission induced by neutrons. Because cosmic rays produce some neutrons, it was difficult to distinguish between induced and spontaneous events. Cosmic rays can be reliably shielded by a thick layer of rock or water. Spontaneous fission was identified in 1940 by Soviet physicists Georgy Flyorov and Konstantin Petrzhak by their observations of uranium in the Moscow Metro Dinamo stati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Observationally Stable
Stable nuclides are nuclides that are not radioactive and so (unlike radionuclides) do not spontaneously undergo radioactive decay. When such nuclides are referred to in relation to specific elements, they are usually termed stable isotopes. The 80 elements with one or more stable isotopes comprise a total of 251 nuclides that have not been known to decay using current equipment (see list at the end of this article). Of these 80 elements, 26 have only one stable isotope; they are thus termed monoisotopic. The rest have more than one stable isotope. Tin has ten stable isotopes, the largest number of stable isotopes known for an element. Definition of stability, and naturally occurring nuclides Most naturally occurring nuclides are stable (about 251; see list at the end of this article), and about 34 more (total of 286) are known to be radioactive with sufficiently long half-lives (also known) to occur primordially. If the half-life of a nuclide is comparable to, or greater t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2.jpg "Click for more on -> Palladium")
%2C_black_and_white.png "Click for more on -> Chemical Element")
_Halflife_of_Radionulides_depending_on_Z²_to_A_ratio.png "Click for more on -> Spontaneous Fission")
