نتایج جستجو برای: cryogenic cooling
تعداد نتایج: 61274 فیلتر نتایج به سال:
Boil-off losses occur when gaseous hydrogen has to be released from a cryogenic tank due liquid evaporating. These are substantial drawback for all areas in which is discussed as potential fuel limit the climate impact. Especially boil-off during fuelling one of most significant source along pathway. To analyse and minimize such losses, simulations filling process performed with simulation tool...
Systems with high-temperature superconductors (HTSC) impose new requirements on power conversions, since the main part of losses in such systems is induced semiconductors converters. Within framework this study, possibility improving static and dynamic characteristics semiconductor diodes using cryogenic cooling was confirmed; some cases, a loss reduction up to 30% achieved.
The replacement of the 30-year-old Philips cryogenerator with a modern LINDE-1630 helium refrigerator is an important component of TRIUMF’s ongoing 500 MeV cyclotron refurbishing program. Two 10.7 m long cryopanels are cooled with liquid helium rather than with 17 K helium gas, as was the case with the cryogenerator. This has increased the pumping speed and, respectively, improved the vacuum in...
Cryogenic fluids have found many practical applications in today’s world, from cooling superconducting magnets to fueling launch vehicles. In many of these applications the cryogenic fluid is initially introduced into piping systems that are in excess of 150 degrees Kelvin higher than the fluid. This leads to voracious evaporation of the fluid and significant pressure fluctuations, which is acc...
Twigs of Salix species are candidates for cryopreservation procedures because they become tolerant of freezing temperatures during mid-winter. We examined several variables in developing a two-step cryopreservation procedure for sections from these twigs. Samples of Salix triandra cooled to -30 or -35 degree C and then transferred to the vapor phase over liquid nitrogen gave the greatest percen...
Low-temperature refrigeration is of crucial importance in fundamental research of condensed matter physics, because the investigations of fascinating quantum phenomena, such as superconductivity, superfluidity, and quantum criticality, often require refrigeration down to very low temperatures. Currently, cryogenic refrigerators with (3)He gas are widely used for cooling below 1 K. However, usag...
This paper investigates coolant topologies for High Temperature Superconducting (HTS) transmission and distribution cable systems. We explore options that allow for flexibility of operation, low temperature rise in the superconductor and low refrigerator power consumption. Topologies for cooling the cryostat and HTS in long-distance electric power transmission systems are explored. For transmis...
High-resolution, germanium detectors (HPGe) have long been used for radionuclide characterization of nuclear sites, both buildings and large areas, for the purpose of cleaning up the site. Several systems consisting of a detector, mobile support, collimators and software for data collection and spectrum analysis have been made by national laboratories and commercial companies. The efficacy of t...
To minimize radiation damage, crystal structures of biological macromolecules are usually determined after rapid cooling to cryogenic temperatures, some 150-200 K below the normal physiological range. The biological relevance of such structures relies on the assumption that flash-cooling is sufficiently fast to kinetically trap the macromolecule and associated solvent in a room-temperature equi...
– We have extended buffer gas cooling to trap atoms with small effective magnetic moments μeff . For μeff ≥ 3μB, 10 atoms were buffer gas cooled, trapped, and thermally isolated in ultra high vacuum with roughly unit efficiency. For μeff < 3μB, the fraction of atoms remaining after full thermal isolation was limited by two processes: wind from the rapid removal of the buffer gas and desorbing h...
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