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Johndale Solem
Johndale C. Solem (born 1941) is an American theoretical physicist and Fellow of Los Alamos National Laboratory. Solem has authored or co-authored over 185 technical papers in many different scientific fields. He is known for his work on avoiding comet or asteroid collisions with Earth and on interstellar spacecraft propulsion. Education and career At Yale University, Johndale C. Solem earned his B.S. ''cum laude'' in Physics in 1963 and his Ph.D. in Physics in 1968. His Ph.D. thesis work under Glen A. Rebka, Jr. was on dynamic nuclear polarization in deuterium hydride. He then joined the Theoretical Division of Los Alamos Scientific Laboratory (subsequently known as Los Alamos National Laboratory) in New Mexico (1969-2000). Concurrently with his research, Solem held several management positions (1971-1988). Some of his appointments were: Group Leader of Thermonuclear Weapons Physics, Group Leader of Neutron Physics, Group Leader of High-Energy-Density Physics, Deputy Divi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Los Alamos National Laboratory
Los Alamos National Laboratory (often shortened as Los Alamos and LANL) is one of the sixteen research and development laboratories of the United States Department of Energy (DOE), located a short distance northwest of Santa Fe, New Mexico, in the American southwest. Best known for its central role in helping develop the first atomic bomb, LANL is one of the world's largest and most advanced scientific institutions. Los Alamos was established in 1943 as Project Y, a top-secret site for designing nuclear weapons under the Manhattan Project during World War II.The site was variously called Los Alamos Laboratory and Los Alamos Scientific Laboratory. Chosen for its remote yet relatively accessible location, it served as the main hub for conducting and coordinating nuclear research, bringing together some of the world's most famous scientists, among them numerous Nobel Prize winners. The town of Los Alamos, directly north of the lab, grew extensively through this period. After ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geometric Phase
In classical and quantum mechanics, geometric phase is a phase difference acquired over the course of a cycle, when a system is subjected to cyclic adiabatic processes, which results from the geometrical properties of the parameter space of the Hamiltonian. The phenomenon was independently discovered by S. Pancharatnam (1956), in classical optics and by H. C. Longuet-Higgins (1958)See page 12 in molecular physics; it was generalized by Sir Michael Berry in (1984). It is also known as the Pancharatnam–Berry phase, Pancharatnam phase, or Berry phase. It can be seen in the conical intersection of potential energy surfaces and in the Aharonov–Bohm effect. Geometric phase around the conical intersection involving the ground electronic state of the C6H3F3+ molecular ion is discussed on pages 385–386 of the textbook by Bunker and Jensen. In the case of the Aharonov–Bohm effect, the adiabatic parameter is the magnetic field enclosed by two interference paths, and it i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supercomputer
A supercomputer is a computer with a high level of performance as compared to a general-purpose computer. The performance of a supercomputer is commonly measured in floating-point operations per second ( FLOPS) instead of million instructions per second (MIPS). Since 2017, there have existed supercomputers which can perform over 1017 FLOPS (a hundred quadrillion FLOPS, 100 petaFLOPS or 100 PFLOPS). For comparison, a desktop computer has performance in the range of hundreds of gigaFLOPS (1011) to tens of teraFLOPS (1013). Since November 2017, all of the world's fastest 500 supercomputers run on Linux-based operating systems. Additional research is being conducted in the United States, the European Union, Taiwan, Japan, and China to build faster, more powerful and technologically superior exascale supercomputers. Supercomputers play an important role in the field of computational science, and are used for a wide range of computationally intensive tasks in var ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Self-assembly
Self-assembly is a process in which a disordered system of pre-existing components forms an organized structure or pattern as a consequence of specific, local interactions among the components themselves, without external direction. When the constitutive components are molecules, the process is termed molecular self-assembly. Self-assembly can be classified as either static or dynamic. In ''static'' self-assembly, the ordered state forms as a system approaches equilibrium, reducing its free energy. However, in ''dynamic'' self-assembly, patterns of pre-existing components organized by specific local interactions are not commonly described as "self-assembled" by scientists in the associated disciplines. These structures are better described as "self-organized", although these terms are often used interchangeably. Self-assembly in chemistry and materials science Self-assembly in the classic sense can be defined as ''the spontaneous and reversible organization of molec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microbotics
Microbotics (or microrobotics) is the field of miniature robotics, in particular mobile robots with characteristic dimensions less than 1 mm. The term can also be used for robots capable of handling micrometer size components. History Microbots were born thanks to the appearance of the microcontroller in the last decade of the 20th century, and the appearance of microelectromechanical systems (MEMS) on silicon, although many microbots do not use silicon for mechanical components other than sensors. The earliest research and conceptual design of such small robots was conducted in the early 1970s in (then) classified research for U.S. intelligence agencies. Applications envisioned at that time included prisoner of war rescue assistance and electronic intercept missions. The underlying miniaturization support technologies were not fully developed at that time, so that progress in prototype development was not immediately forthcoming from this early set of calculations and con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HERO (robot)
HERO (Heathkit Educational RObot) is a series of several educational robots sold by Heathkit during the 1980s. The Heath Company began the HERO 1 project in October 1979, with the first release in 1982. Models include the HERO 1, HERO Jr., and HERO 2000. Heathkit supported the HERO robot line until 1995. All three were produced as kits, or for more money, prebuilt by Heathkit. The 1980s models are considered collectors items, due to their rarity. For the most part, they cannot perform practical tasks, but are more geared toward entertainment and education above all. HERO 1 (ET-18) HERO 1 is a self-contained mobile robot controlled by an onboard computer with a Motorola 6808 CPU and 4 kB of RAM. The robot features light, sound, and motion detectors as well as a sonar ranging sensor. An optional arm mechanism and speech synthesizer was produced for the kit form and included in the assembled form. To make this power available in a simple way, high-level programming languages wer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laser Pumping
Laser pumping is the act of energy transfer from an external source into the gain medium of a laser. The energy is absorbed in the medium, producing excited states in its atoms. When the number of particles in one excited state exceeds the number of particles in the ground state or a less-excited state, population inversion is achieved. In this condition, the mechanism of stimulated emission can take place and the medium can act as a laser or an optical amplifier. The pump power must be higher than the lasing threshold of the laser. The pump energy is usually provided in the form of light or electric current, but more exotic sources have been used, such as chemical or nuclear reactions. Optical pumping Pumping cavities A laser pumped with an arc lamp or a flashlamp is usually pumped through the lateral wall of the lasing medium, which is often in the form of a crystal rod containing a metallic impurity or a glass tube containing a liquid dye, in a condition known as "side-pump ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word "laser" is an acronym for "light amplification by stimulated emission of radiation". The first laser was built in 1960 by Theodore H. Maiman at Hughes Research Laboratories, based on theoretical work by Charles Hard Townes and Arthur Leonard Schawlow. A laser differs from other sources of light in that it emits light which is ''coherent''. Spatial coherence allows a laser to be focused to a tight spot, enabling applications such as laser cutting and lithography. Spatial coherence also allows a laser beam to stay narrow over great distances (collimation), enabling applications such as laser pointers and lidar (light detection and ranging). Lasers can also have high temporal coherence, which allows them to emit light with a very narrow spectrum. Alternatively, temporal coherence can be used to produce ultrashort pulses of ligh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equation Of State
In physics, chemistry, and thermodynamics, an equation of state is a thermodynamic equation relating state variables, which describe the state of matter under a given set of physical conditions, such as pressure, volume, temperature, or internal energy. Most modern equations of state are formulated in the Helmholtz free energy. Equations of state are useful in describing the properties of pure substances and mixtures in liquids, gases, and solid states as well as the state of matter in the interior of stars. Overview At present, there is no single equation of state that accurately predicts the properties of all substances under all conditions. An example of an equation of state correlates densities of gases and liquids to temperatures and pressures, known as the ideal gas law, which is roughly accurate for weakly polar gases at low pressures and moderate temperatures. This equation becomes increasingly inaccurate at higher pressures and lower temperatures, and fails to predict ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shock Wave
In physics, a shock wave (also spelled shockwave), or shock, is a type of propagating disturbance that moves faster than the local speed of sound in the medium. Like an ordinary wave, a shock wave carries energy and can propagate through a medium but is characterized by an abrupt, nearly discontinuous, change in pressure, temperature, and density of the medium. For the purpose of comparison, in supersonic flows, additional increased expansion may be achieved through an expansion fan, also known as a Prandtl–Meyer expansion fan. The accompanying expansion wave may approach and eventually collide and recombine with the shock wave, creating a process of destructive interference. The sonic boom associated with the passage of a supersonic aircraft is a type of sound wave produced by constructive interference. Unlike solitons (another kind of nonlinear wave), the energy and speed of a shock wave alone dissipates relatively quickly with distance. When a shock wave passes through ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gamma-ray Laser
A gamma-ray laser, or graser, is a hypothetical device that would produce coherent gamma rays, just as an ordinary laser produces coherent rays of visible light. Potential applications for gamma-ray lasers include medical imaging, spacecraft propulsion, and cancer treatment. In his 2003 Nobel lecture, Vitaly Ginzburg cited the gamma-ray laser as one of the 30 most important problems in physics. The effort to construct a practical gamma-ray laser is interdisciplinary, encompassing quantum mechanics, nuclear and optical spectroscopy, chemistry, solid-state physics, and metallurgy—as well as the generation, moderation, and interaction of neutrons—and involves specialized knowledge and research in all these fields. The subject involves both basic science and engineering technology. Research The problem of obtaining a sufficient concentration of resonant excited (isomeric) nuclear states for collective stimulated emission to occur turns on the broadening of the gamma-ray ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Explosively Pumped Flux Compression Generator
An explosively pumped flux compression generator (EPFCG) is a device used to generate a high-power electromagnetic pulse by compressing magnetic flux using high explosive. An EPFCG only ever generates a single pulse as the device is physically destroyed during operation. An EPFCG package that could be easily carried by a person can produce pulses in the millions of amperes and tens of terawatts. They require a starting current pulse to operate, usually supplied by capacitors. Explosively pumped flux compression generators are used to create ultrahigh magnetic fields in physics and materials science research and extremely intense pulses of electric current for pulsed power applications. They are being investigated as power sources for electronic warfare devices known as transient electromagnetic devices that generate an electromagnetic pulse without the costs, side effects, or enormous range of a nuclear electromagnetic pulse device. The first work on these generators was condu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
