A Simple Cryostat

1961 ◽  
Vol 14 (4) ◽  
pp. 527
Author(s):  
AS Buchanan ◽  
F Creutzberg
Keyword(s):  
Low Temperature ◽  
Room Temperature ◽  
Temperature Range

A simple all-glass cryostat, based on the LeRoy low-temperature fractionating column, is described. It can be used for the separation, purification, and the determination of vapour pressures of volatile and gaseous compounds in the temperature range -196 �C to room temperature. The vapour pressures of boron trimethyl have been remeasured and the reliability of Stock's data is confirmed.

scholarly journals A novel looped low-temperature heat-driven thermoacoustic refrigerator operating in room temperature range

2019 ◽  
Vol 158 ◽  
pp. 1653-1659 ◽  
Author(s):  
Huizhi Wang ◽  
Guoyao Yu ◽  
Jianying Hu ◽  
Zhanghua Wu ◽  
Mingyu Hou ◽  
...  
Keyword(s):  
Low Temperature ◽  
Room Temperature ◽  
Temperature Range ◽  
Temperature Heat ◽  
Thermoacoustic Refrigerator

Order and disorder in acenaphthylene

1973 ◽  
Vol 334 (1596) ◽  
pp. 19-48 ◽  
Keyword(s):  
Low Temperature ◽  
Room Temperature ◽  
Temperature Structure ◽  
Intermediate Form ◽  
X Ray Diffraction ◽  
Space Group ◽  
Order And Disorder ◽  
Temperature Form ◽  
Diffraction Effects

Acenaphthylene, C 12 H 8 , occurs in space group Pbam (or Pba2) at room temperatures (23 °C) with a = 7.705 (5), b = 7.865 (5), c = 14.071 (5) Å and Z = 4, and is disordered. At about 130 K it undergoes a reversible transition to space group P2 1 nm with a = 7.588 (13), b = 7.549 (10), c = 27.822 (2) Å and Z = 8 (85 K) with an ordered structure. A general study of the system has revealed that the structure of both forms consists of layers of closely packed molecules stacked in the c direction. The room temperature structure has a two-layer repeat and the low temperature form a four-layer repeat. Observation of diffuse X-ray diffraction effects at temperatures close to the transition indicates that an intermediate form having a six-layer repeat is formed. A preliminary structure determination of the low-temperature form reveals that the four layers though having a similar packing scheme differ in the orientation of the constituent molecules relative to c . It is proposed that the almost circular shape of the molecules allows each layer to change its identity under thermal agitation by a rotation of its constituent molecules in their own planes. The transition can be explained in terms of changes of the correlations between neighbouring layers. A simple model based on short-range order parameters is described, which explains the occurrence of the six-layer intermediate and the observed sequence of diffuse diffraction phenomena. The nature of the structure of the disordered room temperature form, which is predicted by this model, is confirmed as far as possible with the data available which are limited because of the dearth of high-angle diffraction maxima.

Resistance determination of joints of plastic components, made by additive technologies, to effect of negative temperatures

2021 ◽  
Vol 0 (1) ◽  
pp. 23-27
Author(s):  
I. S. Nefyolov ◽  
◽  
N. I. Baurova ◽  
Keyword(s):  
Low Temperature ◽  
Room Temperature ◽  
Negative Influence ◽  
Strength Properties ◽  
Additive Technologies ◽  
Strength Characteristics ◽  
Hot Gas ◽  
Negative Temperatures ◽  
Plastic Components

The effect of negative temperatures on strength characteristics of plastic component joints (hot gas welding, gluing, 3D-welding) made with the use of additive technologies has been examined. It has been found out that 3D-wlding allows one to produce joints with the highest strength properties. It was shown that low temperature values (–30 °С) did not have the negative influence on strength properties of ABS-plastic joints but even increased them as compared with analogues samples tested at the room temperature.

Raman microspectroscopy of noncancerous and cancerous human breast tissues. Identification and phase transitions of linoleic and oleic acids by Raman low-temperature studies

The Analyst ◽  
2015 ◽  
Vol 140 (7) ◽  
pp. 2134-2143 ◽  
Author(s):  
Beata Brozek-Pluska ◽  
Monika Kopec ◽  
Jakub Surmacki ◽  
Halina Abramczyk
Keyword(s):  
Phase Transitions ◽  
Low Temperature ◽  
Room Temperature ◽  
Raman Microspectroscopy ◽  
Vibrational Properties ◽  
Human Breast ◽  
Temperature Range ◽  
Breast Tissues

We present the results of Raman studies in the temperature range of 293–77 K on vibrational properties of linoleic and oleic acids and Raman microspectroscopy of human breast tissues at room temperature.

scholarly journals (E)-4-Bromo-2-[(phenylimino)methyl]phenol: a new polymorph and thermochromism

2020 ◽  
Vol 76 (11) ◽  
pp. 1001-1004
Author(s):  
Helen E. Mason ◽  
Judith A. K. Howard ◽  
Hazel A. Sparkes
Keyword(s):  
Hydrogen Bond ◽  
Low Temperature ◽  
Structure Determination ◽  
Room Temperature ◽  
Dihedral Angles ◽  
Temperature Structure ◽  
Aromatic Rings

A new polymorph of (E)-4-bromo-2-[(phenylimino)methyl]phenol, C13H10BrNO, is reported, together with a low-temperature structure determination of the previously published polymorph. Both polymorphs were found to have an intramolecular O—H...N hydrogen bond between the phenol OH group and the imine N atom, forming an S(6) ring. The crystals were observed to have different colours at room temperature, with the previously published polymorph being more orange and the new polymorph more yellow. The planarity of the molecule in the two polymorphs was found to be significantly different, with dihedral angles (Φ) between the two aromatic rings for the previously published `orange' polymorph of Φ = 1.8 (2)° at 120 K, while the new `yellow' polymorph had Φ = 45.6 (1)° at 150 K. It was also observed that both polymorphs displayed some degree of thermochromism and upon cooling the `orange' polymorph became more yellow, while the `yellow' polymorph became paler upon cooling.

Low-temperature behaviour of K2Sc[Si2O6]F: determination of the lock-in phase and its relationships with fresnoite- and melilite-type compounds

2017 ◽  
Vol 73 (5) ◽  
pp. 923-930
Author(s):  
C. Hejny ◽  
L. Bindi
Keyword(s):  
Low Temperature ◽  
Room Temperature ◽  
Temperature Structure ◽  
X Ray Diffraction ◽  
Temperature Behaviour ◽  
Modulated Structure ◽  
Incommensurate Structure ◽  
Commensurate Phase ◽  
Lock In

K2Sc[Si2O6]F exhibits, at room temperature, a (3 + 2)-dimensional incommensurately modulated structure [a= 8.9878 (1),c= 8.2694 (2) Å,V= 668.01 (2) Å3; superspace groupP42/mnm(α,α,0)000s(−α,α,0)0000] with modulation wavevectorsq1= 0.2982 (4)(a* +b*) andq2= 0.2982 (4)(−a* +b*). Its low-temperature behaviour has been studied by single-crystal X-ray diffraction. Down to 45 K, the irrational component α of the modulation wavevectors is quite constant varying from 0.2982 (4) (RT), through 0.2955 (8) (120 K), 0.297 (1) (90 K), 0.298 (1) (75 K), to 0.299 (1) (45 K). At 25 K it approaches the commensurate value of one-third [i.e.0.332 (3)]: thus indicating that the incommensurate–commensurate phase transition takes place between 45 K and 25 K. The commensurate lock-in phase of K2Sc[Si2O6]F has been solved and refined with a 3 × 3 × 1 supercell compared with the tetragonal incommensurately modulated structure stable at room temperature. This corresponds to a 3 × 1 × 3 supercell in the pseudo-orthorhombic monoclinic setting of the low-temperature structure, space groupP2/m, with lattice parametersa= 26.786 (3),b= 8.245 (2)c= 26.824 (3) Å, β = 90.00 (1)°. The structure is a mixed tetrahedral–octahedral framework composed of chains of [ScO4F2] octahedra that are interconnected by [Si4O12] rings with K atoms in fourfold to ninefold coordination. Distorted [ScO4F2] octahedra are connected to distorted Si tetrahedra to form octagonal arrangements closely resembling those observed in the incommensurate structure of fresnoite- and melilite-type compounds.

THE EFFECT OF PRESSURE ON THE ELECTRICAL RESISTANCE OF RUBIDIUM

1957 ◽  
Vol 35 (6) ◽  
pp. 720-729 ◽  
Author(s):  
J. S. Dugdale ◽  
J. A. Hulbert
Keyword(s):  
Low Temperature ◽  
Electrical Resistance ◽  
Room Temperature ◽  
Residual Resistivity ◽  
Effect Of Pressure ◽  
Temperature Range ◽  
Fluid State

By using helium in both the solid and the fluid state as a pressure-transmitting medium, it has been possible to measure the resistance of rubidium over the temperature range from 2° K. to room temperature at pressures up to 2500 atmospheres. In particular the effect of pressure on the transition at ~200° K., on the low temperature ideal resistivity, and on the residual resistivity was examined.

Damping Capacity of Fe-Ga Alloys

2011 ◽  
Vol 228-229 ◽  
pp. 937-941 ◽  
Author(s):  
Fang Mei Ling ◽  
Jie Zhu ◽  
Li Ji Heng ◽  
Gao Xue Xu
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Wide Temperature Range ◽  
Room Temperature ◽  
Damping Capacity ◽  
Torsion Pendulum ◽  
Temperature Peak ◽  
Temperature Range ◽  
Computer Controlled ◽  
Increasing Temperature

The damping capacity of Fe-Ga rods and sheets has been studied using a computer-controlled automatic inverted torsion pendulum instruments in a wide temperature range in a series of frequency. The frequency and temperature has different influence on the damping capacity of solidified Fe83Ga17 rods and (Fe83Ga17)97.25Cr2B0.75 sheets. The damping capacity of all specimens increased with frequencies. The solidified Fe-Ga rods showed an obvious low-temperature peak and a potential high-temperature peak with increasing temperature. However, the damping capacity of Fe-Ga sheets kept steady in a wide temperature range and then rapidly increased on further heating above 400°C. Damping capacity of about 0.02 was obtained in both Fe-Ga rods and sheets at temperatures from room temperature to 500°C. Thus, The Fe-Ga alloys are considered to be a class of promising high damping alloys.

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