HIGH PULSED FIELD MAGNETORESISTANCE IN INDIUM ANTIMONIDE AND INDIUM ARSENIDE

1963 ◽  
Vol 41 (6) ◽  
pp. 890-922 ◽  
Author(s):  
C. H. Champness
Keyword(s):  
Indium Arsenide ◽  
Indium Antimonide ◽  
Room Temperature ◽  
Fold Increase ◽  
Individual Bands ◽  
Conduction Theory ◽  
The Individual ◽  
Pulsed Fields ◽  
Maximum Field ◽  
Oriented Single Crystal

Measurements of transverse magnetoresistance have been made using pulsed fields up to about 300 kilo-oersteds on oriented single-crystal samples of near-intrinsic indium antimonide and extrinsic indium arsenide at room temperature. At the maximum field, about a 400-fold resistivity increase was found in indium antimonide and about a 4-fold increase in indium arsenide. The variation with field can largely be accounted for by classical two-carrier conduction theory, even though ħωc/kT > 1 and [Formula: see text] for the electrons in indium antimonide. At the lower fields in indium antimonide the individual bands alone give no measurable contribution to the magnetoresistance, indicating that for the electrons at least, the relaxation time must be almost independent of energy. While no strong evidence of Landau quantization effects was apparent, the magnetoresistance values at the higher fields in general fell below the classical theoretical curve. This could be interpreted as a variation of the electron mobility at high fields such that approximately [Formula: see text].

MAGNETORESISTANCE AND HALL EFFECT IN ORIENTED SINGLE CRYSTAL SAMPLES OF n-TYPE INDIUM ANTIMONIDE

1961 ◽  
Vol 39 (3) ◽  
pp. 452-467 ◽  
Author(s):  
C. H. Champness
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Single Crystal ◽  
Hall Effect ◽  
Air Temperature ◽  
Indium Antimonide ◽  
Room Temperature ◽  
Magneto Resistance ◽  
Longitudinal Magnetoresistance ◽  
Oriented Single Crystal

Measurements have been made on the angular dependence of the magneto-resistance effect and the Hall effect on oriented n-type indium antimonide samples. The measurements were taken at room temperature and liquid air temperature using a magnetic field strength of about 5000 gauss. Besides evidence of inhomogeneity, the results show directional dependence of the longitudinal magnetoresistance. The largest value was found in the [Formula: see text] direction. This can be explained if, in addition to electrons at the central minimum, there is some filling of the [Formula: see text] minima in k space.

Heterobimetallische 3d-4f-Komplexe mit Bis(1,2-dithiooxalato)nickelat(II) als planarem Brückenbaustein / Heterobimetallic 3d-4f-Complexes with Bis(1,2-dithiooxalato)nickelate(II) as Planar Bridging Block

2005 ◽  
Vol 60 (11) ◽  
pp. 1149-1157 ◽  
Author(s):  
Matthias Siebold ◽  
Alexandra Kelling ◽  
Uwe Schilde ◽  
Peter Strauch
Keyword(s):  
Room Temperature ◽  
Magnetic Moments ◽  
Lanthanide Ions ◽  
Water Molecules ◽  
Unit Cell Parameters ◽  
Ionic Radii ◽  
X Ray ◽  
Cell Parameters ◽  
Heterobimetallic Complexes ◽  
The Individual

Planar bis(1,2-dithiooxalato)nickelates(II) react in aqueous solutions of lanthanide ions to form pentanuclear, heterobimetallic complexes of the general composition [{Ln(H2O)n}2- {Ni(dto)2}3]・xH2O (Ln = Y3+, La3+, Ce3+, Pr3+, Nd3+, Sm3+, Eu3+, Gd3+, Tb3+, Dy3+, Ho3+, Er3+, Tm3+, Yb3+, Lu3+; n = 4 or 5; x = 9 - 12). With [{Nd(H2O)5}2{Ni(S2C2O2)2}3]・xH2O (x = 10 - 12) (1) and [{Er(H2O)4}2{Ni(S2C2O2)2}3]・xH2O (x = 9 - 10) (2) we were able to isolate two complexes of this series as single crystals, which were characterized by X-ray structure analysis. Depending on the individual ionic radii of the lanthanide ions, the compounds crystallize in two different crystal systems with the following unit cell parameters: 1, monoclinic in P21/c with a = 11.3987(13), b = 11.4878(8), c = 20.823(2) Å , β = 98.907(9)° and Z = 2; 2, triclinic in P1̅ with a = 10.5091(6), b = 11.0604(6), c = 11.2823(6) Å , α = 107.899(4)°, β = 91.436(4)°, γ = 112.918(4)° and Z = 1. The channels and cavities appearing in the packing of the molecules are occupied by uncoordinated water molecules. High magnetic moments up to 14.65 BM./f.u. have been observed at room temperature due to the combined moments of the individual lanthanide ions.

scholarly journals The Chemical Shift of the 29Si Nuclear Magnetic Resonance in a Synthetic Single Crystal of Mg2SiO4

1985 ◽  
Vol 40 (2) ◽  
pp. 126-130 ◽  
Author(s):  
N. Weiden ◽  
H. Rager
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shift ◽  
Single Crystal ◽  
Angular Dependence ◽  
Room Temperature ◽  
Bond Distance ◽  
Chemical Shift Tensor ◽  
The Individual ◽  
Nuclear Magnetic

The angular dependence of the chemical shift of the 29Si nuclear magnetic resonance has been measured in a synthetic single crystal of Mg2SiO4 (space group Pbnm, Z = 4). The measurements were performed at room temperature at a frequency of 39.758 MHz using the FT-NMR technique. The eigenvalues of the shift tensor with respect to 29Si in TMS are δx = - 38.8 ppm, δv = -55.3 ppm and δz = - 95.4 ppm, with the eigenvector y parallel to c and the eigenvector z forming an angle of 7.5° with a. The results show clearly the influence of the individual S i - O bonds on the chemical shift tensor. The chemical shift along the S i -O bond depends in good approximation exponentially on the S i - O bond distance.

Skeletal and Lattice Vibrations of Crystals of Dihalogenobis(pyridine)zinc(II)

1974 ◽  
Vol 52 (11) ◽  
pp. 2005-2015 ◽  
Author(s):  
P. T. T. Wong
Keyword(s):  
Single Molecule ◽  
Room Temperature ◽  
Normal Modes ◽  
Low Frequency ◽  
Far Infrared ◽  
Liquid Nitrogen Temperature ◽  
Lattice Vibrations ◽  
Individual Molecule ◽  
Stretching Vibrations ◽  
The Individual

Detailed measurements of the low-frequency Raman spectra of the crystals of [ZnPy2Cl2] and [ZnPy2Br2] at room temperature, where Py is the pyridine molecule, and the far-infrared spectrum of the crystal of [ZnPy2Cl2] at liquid nitrogen temperature have been made. The vibrational frequencies for the single molecule and for the complete crystal of these two complexes have been calculated and compared with the observed spectra, and the distribution of the potential energy of the normal modes has also been calculated to assist the refinement of the calculation and the interpretation of the spectra. Apparently, the skeletal Zn–ligand vibrations of the individual molecule couple with the lattice vibrations in the crystal, except for the normal modes at 326 cm−1 for [ZnPy2Cl2] and at 250 cm−1 for [ZnPy2Br2] which are dominated by the Zn–halogen stretching vibrations. Reasonably good Zn–ligand stretching force constants were obtained. The nature of the coordination bonds of these complexes has been discussed.

scholarly journals Stability of Propofol (2,6-Diisopropylphenol) in Thermal Desorption Tubes during Air Transport

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Felix Maurer ◽  
Martin Geiger ◽  
Thomas Volk ◽  
Daniel I. Sessler ◽  
Sascha Kreuer ◽  
...  
Keyword(s):  
Room Temperature ◽  
Pharmacokinetic Studies ◽  
Gas Generator ◽  
Individual Values ◽  
Liquid Injection ◽  
Refrigerated Transport ◽  
Liquid Preparation ◽  
The Stability ◽  
The Individual ◽  
Sample Set

The anesthetic propofol and other exhaled organic compounds can be sampled in Tenax sorbent tubes and analyzed by gas chromatography coupled with mass spectrometry. The aim of this study was to evaluate the stability of propofol in Tenax sorbent tubes during overseas shipping. This is relevant for international pharmacokinetic studies on propofol in exhaled air. Tenax sorbent tube propofol samples with concentrations between 10 and 100 ng were prepared by liquid injection and with a calibration gas generator. For each preparation method, one reference set was analyzed immediately after preparation, a second set was stored at room temperature, and a third one was stored refrigerated. The fourth set was sent from Germany by airmail to USA and back. The shipped set of tubes was analyzed when it returned after 55 days elapsed. Then, the room temperature samples and the refrigerated stored samples were also analyzed. To evaluate the stability of propofol in the stored and shipped tubes, we calculated the recovery rates of each sample set. The mean recovery in the stored samples was 101.2% for the liquid preparation and 134.6% for the gaseous preparation at 4°C. At 22°C, the recovery was 96.1% for liquid preparation and 92.1% for gaseous preparation, whereas the shipped samples had a recovery of 85.3% and 111.3%. Thus, the deviation of the shipped samples is within a range of 15%, which is analytically acceptable. However, the individual values show significantly larger deviations of up to -32.1% (liquid) and 30.9% (gaseous). We conclude that storage of propofol on Tenax tubes at room temperature for 55 days is possible to obtain acceptable results. However, it appears that due to severe temperature and pressure variations air shipment of propofol samples in Tenax tubes without cooling shows severe deviations from the initial concentration. Although it was not tested in this study, we assume that refrigerated transport might be necessary to obtain comparable results as in the stored samples.

scholarly journals Mesomorphic Phase Behavior in Comb-like Polymer- Surfactant Complex

e-Polymers ◽  
2006 ◽  
Vol 6 (1) ◽  
Author(s):  
Isamu Akiba ◽  
Hiroyasu Masunaga ◽  
Shouichi Murata ◽  
Kanako Sasaki
Keyword(s):  
Optical Anisotropy ◽  
Sulfonic Acid ◽  
Room Temperature ◽  
Ethyl Acrylate ◽  
Lamellar Phase ◽  
Surfactant Complex ◽  
Lamellar Morphology ◽  
Dodecylbenzene Sulfonic Acid ◽  
The Individual ◽  
Polymer Surfactant

AbstractIt was found that a comb-like complex consisting of poly[2-(N,Ndimethylamino) ethyl acrylate] (PDAEA) and p-dodecylbenzene sulfonic acid (DBSA) formed mesomorphically ordered lamellar phase at room temperature where PDAEA and DBSA are in molten state. The lamellar phase shows optical anisotropy, although the individual components are always isotropic. In addition it is found that the optical anisotropy of the PDAEA-DBSA complex completely disappears with accompanying order-disorder transition of the lamellar morphology with elevating temperature.

Ligand Redistribution Equilibria in Aqueous Fluoroberyllate Solutions

1998 ◽  
Vol 53 (11) ◽  
pp. 1294-1300 ◽  
Author(s):  
Michael Schmidt ◽  
Hubert Schmidbaur
Keyword(s):  
Experimental Data ◽  
Ligand Exchange ◽  
Room Temperature ◽  
Chemical Shifts ◽  
Equilibrium Constants ◽  
Individual Species ◽  
Ph Values ◽  
Exchange Processes ◽  
The Individual ◽  
Good Agreement

The composition of aqueous fluoroberyllate solutions has been studied by 9Be and 19F NMR spectroscopy for various ratios of the beryllium and fluorine concentrations, and at different pH values. The equilibrium constants have been determined for the ligand exchange processes, which involve the species [Be(OH2)4]2+, [BeF(OH2)3]+, [BeF2(OH2)2], [BeF3(OH2)]- , and [BeF4]2-. These equilibria are shifted towards [BeF4]2- at high pH. No polynuclear fluoroberyllates have been detected. The fluoride exchange between the individual species is slow on the NMR time scale at room temperature, and separate sharp signals with the expected multiplicity are therefore recorded. Calculated 9Be chemical shifts are in good agreement with experimental data.

Picosecond carrier dynamics and studies of Auger recombination processes in indium arsenide at room temperature

1992 ◽  
Vol 46 (20) ◽  
pp. 13194-13200 ◽  
Author(s):  
K. L. Vodopyanov ◽  
H. Graener ◽  
C. C. Phillips ◽  
T. J. Tate
Keyword(s):  
Indium Arsenide ◽  
Room Temperature ◽  
Auger Recombination ◽  
Carrier Dynamics ◽  
Recombination Processes

Thermoelectric Figure of Merit Calculations for Nanowires –The Moderate Confinement Regime

2010 ◽  
Vol 1267 ◽  
Author(s):  
Jane Cornett ◽  
Oded Rabin
Keyword(s):  
Indium Antimonide ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Thermoelectric Figure Of Merit ◽  
Wire Radius ◽  
Thermoelectric Figure ◽  
High Level ◽  
Case Basis ◽  
Strong Confinement

AbstractWe report room temperature ZT calculations for silicon and indium antimonide nanowires of varying radii. Interestingly, some systems deviate significantly from the anticipated trend of ZT vs. radius. The InSb results are particularly remarkable due to the non-monotonic relationship seen between n-type ZT and wire radius; where typically we expect to see only a decrease with increasing radius, for InSb ZT increases between 20 and 100 nm wire radii. This is thought to be due to the high level of degeneracy of subbands for larger nanowire radii. These results indicate that the monotonic relationship between ZT and wire radius observed under strong confinement conditions cannot be assumed, but must be tested on a case-by-case basis for each materials system.

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