scholarly journals Atomic Theory of Liquid Helium Near Absolute Zero

1953 ◽  
Vol 91 (6) ◽  
pp. 1301-1308 ◽  
Author(s):  
R. P. Feynman
Keyword(s):  
Liquid Helium ◽  
Absolute Zero ◽  
Atomic Theory

scholarly journals CRYOGENIC AIR CONDITIONING OF MOTOR VEHICLES

2014 ◽  
pp. 100-103
Author(s):  
M. JAIVIGNESH ◽  
DR. B. VIJAYA RAMNATH
Keyword(s):  
Low Temperature ◽  
Liquid Helium ◽  
Liquid Nitrogen ◽  
Low Temperatures ◽  
Air Conditioning ◽  
Absolute Zero ◽  
Motor Vehicles ◽  
Air Conditioning System ◽  
Low Temperature Refrigeration ◽  
Physical Phenomena

Cryogenics is the branch of physics and engineering that involves the study of very low temperatures (below 123 K), how to produce them, and how materials behave at those temperatures. It is frequently applied to low temperature refrigeration applications such as in the study of physical phenomena of materials at temperature approaching absolute zero and in the liquefaction of gases. Liquefied gases such as liquid nitrogen and liquid helium are used in many cryogenic applications. Using liquid nitrogen as a refrigerant reduces chloro-fluorocarbon (CFC) emission in atmosphere and it is an eco-friendly technique. This paper deals with usage of liquid nitrogen in air conditioning of motor vehicles. First the preparation of liquid nitrogen is discussed, followed by its storage and working as a refrigerant in air conditioning system. This is followed by its advantages and draw backs.

Blood Freezing to Nearly Absolute Zero Temperature: −272.29°C

1981 ◽  
Vol 103 (1) ◽  
pp. 24-26 ◽  
Author(s):  
E. G. Cravalho ◽  
C. E. Huggins ◽  
K. R. Diller ◽  
W. W. Watson
Keyword(s):  
Liquid Helium ◽  
High Vacuum ◽  
Human Erythrocytes ◽  
Absolute Zero ◽  
Zero Temperature ◽  
Normal Range ◽  
Biological Assays ◽  
Intracellular Potassium ◽  
Edta Solution ◽  
2,3 Dpg

Human erythrocytes were collected in ACD anticoagulant, glycerolized with an equal volume of 8.6 M glycerol, 8 percent glucose, 1 percent fructose, and 0.3 percent Na2 EDTA solution, sealed in glass ampules, and frozen to −272.29°C (0.86°K) in liquid helium under high vacuum. Biological assays performed after thawing and three-stage dialysis to remove the glycerol showed less than 1 percent hemolysis. Intracellular potassium, 2,3 DPG, and ATP were within the normal range.

Systematic effects in observed parallaxes

1978 ◽  
Vol 48 ◽  
pp. 31-35
Author(s):  
R. B. Hanson
Keyword(s):  
Error Estimates ◽  
Zero Point ◽  
Absolute Zero ◽  
Apparent Magnitude ◽  
Coherent System ◽  
Preliminary Results ◽  
General Catalogue ◽  
Systematic Effects ◽  
New Evidence ◽  
Right Ascension

Several outstanding problems affecting the existing parallaxes should be resolved to form a coherent system for the new General Catalogue proposed by van Altena, as well as to improve luminosity calibrations and other parallax applications. Lutz has reviewed several of these problems, such as: (A) systematic differences between observatories, (B) external error estimates, (C) the absolute zero point, and (D) systematic observational effects (in right ascension, declination, apparent magnitude, etc.). Here we explore the use of cluster and spectroscopic parallaxes, and the distributions of observed parallaxes, to bring new evidence to bear on these classic problems. Several preliminary results have been obtained.

A Superconducting Microscope

1971 ◽  
Vol 29 ◽  
pp. 10-11 ◽  
Author(s):  
R. E. Worsham ◽  
J. E. Mann ◽  
E. G. Richardson
Keyword(s):  
Liquid Helium ◽  
Focal Length ◽  
Vacuum System ◽  
Objective Lens ◽  
Electrical Instability ◽  
Radiation Shields ◽  
And Control ◽  
Thermal Oscillations ◽  
Flux Pump

This superconducting microscope, Figure 1, was first operated in May, 1970. The column, which started life as a Siemens Elmiskop I, was modified by removing the objective and intermediate lenses, the specimen chamber, and the complete vacuum system. The large cryostat contains the objective lens and stage. They are attached to the bottom of the 7-liter helium vessel and are surrounded by two vapor-cooled radiation shields.In the initial operational period 5-mm and 2-mm focal length objective lens pole pieces were used giving magnification up to 45000X. Without a stigmator and precision ground pole pieces, a resolution of about 50-100Å was achieved. The boil-off rate of the liquid helium was reduced to 0.2-0.3ℓ/hour after elimination of thermal oscillations in the cryostat. The calculated boil-off was 0.2ℓ/hour. No effect caused by mechanical or electrical instability was found. Both 4.2°K and 1.7-1.9°K operation were routine. Flux pump excitation and control of the lens were quite smooth, simple, and, apparently highly stable. Alignment of the objective lens proved quite awkward, however, with the long-thin epoxy glass posts used for supporting the lens.

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