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Nuclear Energy Science Tracer Bullet (Library of Congress)
Nuclear Power (Wolfram Alpha)
These are organized by a classification scheme developed exclusively for Cosma. More…
CODATA Internationally recommended values of the Fundamental Physical Constants, Atomic and Nuclear (NIST Reference on Constants, Units and Uncertainty)
Radiation, Radioactivity & Radiobiology (Martindale’s Reference Desk)
atom : the smallest particle of an element that can exist either alone or in combination — Webster
Atom is the smallest constituent unit of ordinary matter that has the properties of a chemical element. Every solid, liquid, gas, and plasma is composed of neutral or ionized atoms. Atoms are extremely small; typical sizes are around 100 picometers (a ten-billionth of a meter, in the short scale).
Every atom is composed of a nucleus and one or more electrons bound to the nucleus. The nucleus is made of one or more protons and typically a similar number of neutrons. Protons and neutrons are called nucleons. More than 99.94% of an atom’s mass is in the nucleus. The protons have a positive electric charge, the electrons have a negative electric charge, and the neutrons have no electric charge. If the number of protons and electrons are equal, that atom is electrically neutral. If an atom has more or fewer electrons than protons, then it has an overall negative or positive charge, respectively, and it is called an ion.
The electrons of an atom are attracted to the protons in an atomic nucleus by this electromagnetic force. The protons and neutrons in the nucleus are attracted to each other by a different force, the nuclear force, which is usually stronger than the electromagnetic force repelling the positively charged protons from one another. Under certain circumstances, the repelling electromagnetic force becomes stronger than the nuclear force, and nucleons can be ejected from the nucleus, leaving behind a different element: nuclear decay resulting in nuclear transmutation.
The number of protons in the nucleus defines to what chemical element the atom belongs: for example, all copper atoms contain 29 protons. The number of neutrons defines the isotope of the element. The number of electrons influences the magnetic properties of an atom. Atoms can attach to one or more other atoms by chemical bonds to form chemical compounds such as molecules. The ability of atoms to associate and dissociate is responsible for most of the physical changes observed in nature and is the subject of the discipline of chemistry. — Wikipedia
Atomic Physics is the field of physics that studies atoms as an isolated system of electrons and an atomic nucleus. It is primarily concerned with the arrangement of electrons around the nucleus and the processes by which these arrangements change.
The term atomic physics can be associated with nuclear power and nuclear weapons, due to the synonymous use of atomic and nuclear in standard English. Physicists distinguish between atomic physics — which deals with the atom as a system consisting of a nucleus and electrons — and nuclear physics, which considers atomic nuclei alone. — Wikipedia
Nuclear physics is the field of physics that studies atomic nuclei and their constituents and interactions. Other forms of nuclear matter are also studied. Nuclear physics should not be confused with atomic physics, which studies the atom as a whole, including its electrons. — Wikipedia
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Two-micron fill tubes fill two needs
on December 13, 2018 at 12:59 pm
Lawrence Livermore National Laboratory's National Ignition Facility (NIF) and General Atomics engineers have created an inertial confinement fusion (ICF) fuel capsule with a two-micron-diameter fill tube—and along the way, found a solution to a "Bay Bridge"-like dilemma that could have dramatically slowed the process of fabricating NIF capsules. […]
Chemists find a new tool for understanding...
on December 11, 2018 at 4:28 pm
Yale scientists have taken a novel approach to unraveling the complex structure and regulation of enzymes: They Googled it. […]
Physicists edge closer to controlling chemical...
on December 11, 2018 at 2:50 pm
A team of researchers from the Moscow Institute of Physics and Technology, and Aarhus University in Denmark has developed an algorithm for predicting the effect of an external electromagnetic field on the state of complex molecules. The algorithm, which is based on a theory developed earlier by the same team, predicts tunneling ionization rates of molecules. This refers to the probability that an electron will bypass the potential barrier and escape from its parent molecule. The new algorithm, […]
Researchers image atomic structure of important...
on December 10, 2018 at 5:43 pm
A new study by investigators from Brigham and Women's Hospital provides a biophysical and structural assessment of a critical immune regulating protein called human T-cell immunoglobulin and mucin domain containing protein-3 (hTIM-3). Understanding the atomic structure of hTIM-3 provides new insights for targeting this protein for numerous cancer and autoimmune therapeutics currently under clinical development. The findings of this study were published online in Scientific Reports on Nov. 30. […]
Hunting for rare isotopes: The mysterious...
on December 7, 2018 at 3:40 pm
When you hear the term "radioactive" you likely think "bad news," maybe along the lines of fallout from an atomic bomb. […]