LARGE ROOM TEMPERATURE MAGNETORESISTANCE IN (La0.7Sm0.3)0.7Sr0.3MnO3/Agx COMPOSITES

2005 ◽  
Vol 19 (30) ◽  
pp. 4467-4473 ◽  
Author(s):  
XIAO-BO YUAN ◽  
YI-HUA LIU ◽  
CHENG-JIAN WANG ◽  
LIANG-MO MEI
Keyword(s):  
Experimental Data ◽  
Grain Boundaries ◽  
Room Temperature ◽  
Composite System ◽  
Molar Ratio ◽  
Ag Addition ◽  
Brillouin Function ◽  
Spin Clusters ◽  
Good Agreement

The effects of Ag addition in the composite ( La 0.7 Sm 0.3)0.7 Sr 0.3 MnO 3/ Ag x (abbreviated as LSSMO/Ag x) has been studied. The results showed that Ag addition induces the decrease in resistivity (ρ) due to the improvement of grain boundaries resulted from the segregation of Ag on the grain surfaces. In addition, 27% molar ratio of Ag addition induces a large room temperature magnetoresistance (MR) ratio of 35%. The good agreement of experimental data with Brillouin function indicates that the MR behavior in this composite system accounts for the spin-dependent hopping of the electrons between the spin clusters.

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.

Nernst–Ettingshausen Effects in GaxIn1–xAs alloys

1973 ◽  
Vol 51 (22) ◽  
pp. 2369-2375 ◽  
Author(s):  
Denis J. E. Demars ◽  
John C. Woolley
Keyword(s):  
Experimental Data ◽  
Magnetic Fields ◽  
Effective Mass ◽  
Room Temperature ◽  
Optical Scattering ◽  
Temperature Measurements ◽  
Scattering Coefficient ◽  
Alloy Sample ◽  
Alloy Scattering ◽  
Good Agreement

Room temperature measurements of longitudinal and transverse Nernst–Ettingshausen coefficients [Formula: see text] have been made on samples of GaxIn1–xAs alloys for a range of magnetic fields (B) up to 3.2 Wb/m2. Previous theoretical expressions for the values of these coefficients have been extended to the case of electrons in a single Kane band, and hence expressions for [Formula: see text] and [Formula: see text] obtained in terms of B, the bottom of the band effective mass m0*, and the scattering coefficient s. Fitting of these expressions to the experimental data thus has given values of m0* and s for each alloy sample. The values of m0* are found to be in good agreement with those obtained previously from plasma reflectance work, while the values of s indicate that over most of the alloy range polar optical scattering is predominant, but that in the range 0.4 < x < 0.7, alloy scattering may also have some contribution.

Springback Behavior of an Invar Sheet and Its Perforated Form

2006 ◽  
Vol 505-507 ◽  
pp. 781-786
Author(s):  
Yi Che Lee ◽  
Fuh Kuo Chen
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Tensile Tests ◽  
Test Results ◽  
Bending Tests ◽  
Predicted Values ◽  
Springback Behavior ◽  
Good Agreement

The springback behavior of an invar sheet and its perforated form were examined in the present study. The mechanical properties for invar sheet and perforated invar-sheet at elevated temperatures were first obtained from tensile tests. The test results suggest that both invar sheet and perforated invar-sheet have favorable formability at temperature higher than 200oC. An analytical model was also established to predict the springback of the invar sheet and its perforated form under bending conditions at various elevated temperatures. In order to verify the predicted results, the V-bending tests were conducted for the invar sheet at various temperatures ranging from room temperature to 300. The experimental data indicate that the springback decreases with the rise in temperature for both invar sheet and perforated invar-sheet. The good agreement between the experimental data and the predicted values confirms the validity of the proposed theoretical model as well.

scholarly journals Experimentelle und semi-empirische Protonen-Hyperfein- kopplungen von 1.3-Benzodioxol-Radikal-Kationen und ihre Korrelation mit Reaktivitäten in elektrophilen Substitutionen

1982 ◽  
Vol 37 (7) ◽  
pp. 680-687 ◽  
Author(s):  
Jörg Fleischhauer ◽  
Sun Ma ◽  
Wolfgang Schleker ◽  
Klaus Gersonde ◽  
Hans Twilfer
Keyword(s):  
Experimental Data ◽  
Perturbation Theory ◽  
Hyperfine Splitting ◽  
Electrophilic Substitution ◽  
Room Temperature ◽  
Hydrogen Atoms ◽  
Substitution Reactions ◽  
X Band ◽  
Band Spectra ◽  
Good Agreement

Abstract The solution ESR X-band spectra of 1.3-benzodioxole (methylenedioxybenzene) (1), benzo- [1.2-d:4.5-d']bis[1.3]dioxole (2), benzo[1.2-d:3.4-d']bis[1.3]dioxole (3) and benzotris[1.3]dioxole (4) have been measured at room temperature. Hyperfine splitting constants of the aromatic ring protons of the compounds 1 - 3 have been determined. They have been correlated with the HOMO orbital densities of the adjacent carbon atoms and exhibit sufficient correspondence with the reactivities of these compounds in electrophilic substitution reactions. The splitting constants of all protons of the compounds 1 - 4 have been calculated by the INDO and HMO methods and have been compared with the experimental hyperfine values. By perturbation theory applied to the interactions between the π-MO'S of benzene and the dioxole fragment one can explain and understand the magnitudes of the experimental hyperfine splitting constants of the hydrogen atoms of these compounds. In particular, the hyperfine values of the methylene protons calculated by the HMO method are in good agreement with the experimental data.

Prediction of Yield in Ductile Materials Operating at Creep Temperatures

1977 ◽  
Vol 99 (3) ◽  
pp. 425-428
Author(s):  
G. M. Kurajian ◽  
T. Y. Na
Keyword(s):  
Experimental Data ◽  
Elevated Temperature ◽  
Yield Strength ◽  
Yield Point ◽  
Room Temperature ◽  
Ductile Metals ◽  
Ductile Materials ◽  
Machine Element ◽  
Creep Temperature ◽  
Good Agreement

Utilizing a thermodynamic approach, this paper provides the designer with formulations and data so that he can obtain or verify, and then employ, the yield strength (or yield point) value he may desire in the design of a particular ductile machine element operating in the creep temperature range. A previous paper by the authors [1] dealt with the prediction of failure of such elements in the range between room temperature and the lower creep temperature. Thus, the present paper in conjunction with [1], and the references in both, is to provide a thermodynamic explanation for failure of such elements operating in elevated temperature environments ranging from room through creep temperatures. Specific applications are taken for three selected categories of steel with good agreement between the theory and experimental data. However, with necessary data, the procedures in this paper, as it was in [1], is expected to be applicable to other ductile metals as well.

Ordering of Oxygen Atoms in YBA2CU3O6+X and its Effects on Superconducting Properties

1987 ◽  
Vol 99 ◽  
Author(s):  
Keikichi Nakamura ◽  
Takeshi Hatano ◽  
Shozo Ikeda ◽  
Keiichi Ogawa
Keyword(s):  
Experimental Data ◽  
Oxygen Content ◽  
Low Temperatures ◽  
Room Temperature ◽  
Orthorhombic Phase ◽  
Superconducting Phase ◽  
Superconducting Transition ◽  
Superconducting Properties ◽  
Good Agreement ◽  
Oxygen Atoms

ABSTRACTOrdering of oxygen atoms in YBa2Cu3O6+x has been analysed by employing statistical thermodynamics ana the results are compared with the experimental data. The axial lengths a and b at room temperature were determined experimentally as a function of oxygen content and were found to show good agreement with the calculated lengths a and b. Special care was taken in the above experiment to dope oxygen atoms into the sample at low temperatures, typically 400° C. The superconducting transition temperature of the sample doped with oxygen at 400°C(starting material:YBa2Cu3O6.1.(decreases linearly with decreasing the oxygen content from 6+x=6.9(92 K) to 6.38(30 K) and decreased sharply around 6+x=6.35(5 K). No distinct superconducting phase corresponding to further ordered orthorhombic phase has been observed in this case.

scholarly journals Statistically Optimum HKUST-1 Synthesized by Room Temperature Coordination Modulation Method for the Adsorption of Crystal Violet Dye

Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6430
Author(s):  
Christian J. Wijaya ◽  
Suryadi Ismadji ◽  
Hakun W. Aparamarta ◽  
Setiyo Gunawan
Keyword(s):  
Acetic Acid ◽  
Statistical Analysis ◽  
Acid Concentration ◽  
Room Temperature ◽  
Modulation Method ◽  
Molar Ratio ◽  
Synthesis Methods ◽  
Acetic Acid Concentration ◽  
Crystal Violet Dye ◽  
Good Agreement

Due to its excellency and versatility, many synthesis methods and conditions were developed to produce HKUST-1 ([Cu3(BTC)2(H2O)3]n). However, the diversity of HKUST-1 was actually generated both in terms of characteristics and morphologies. Hence, the consistency of HKUST-1 characteristics and morphologies needs to be maintained. The statistical analysis and optimization provide features to determine the best synthesis condition. Here, a room-temperature coordination modulation method was proposed to maintain the morphology of HKUST-1 while reducing energy consumption. In addition, response surface methodology (RSM) was used to demonstrate the statistical analysis and optimization of the synthesis of HKUST-1. The molar ratio of ligand to metal, reaction time, and acetic acid concentration were studied to determine their effects on HKUST-1. The optimum HKUST-1 was obtained by the synthesis with a molar ratio of ligand to metal of 0.4703 for 27.2 h using 5% v/v acetic acid concentration. The statistical analysis performed a good agreement with the experimental data and showed the significance of three desired parameters on HKUST-1. The optimum HKUST-1 had the adsorption capacity of 1005.22 mg/g with a removal efficiency of 92.31% towards CV dye. It could be reused up to 5 cycles with insignificant decrease in performance.

Modeling the Magnetic Properties of La0.62Er0.05Ba0.33Fe0.2Mn0.8O3: Mean-Field Study and Bean Rodbell Model

2020 ◽  
Vol 17 (4) ◽  
pp. 1571-1575
Author(s):  
Samia Yahyaoui ◽  
Amel Abassi ◽  
Mounira Abassi
Keyword(s):  
Experimental Data ◽  
Phase Transition ◽  
Magnetic Properties ◽  
Mean Field ◽  
Total Momentum ◽  
Exchange Parameter ◽  
Brillouin Function ◽  
The Mean ◽  
Good Agreement ◽  
Second Order Phase Transition

The Brillouin function, the phase transition and the related magnetic properties in La0.62Er0.05Ba0.33Fe0.2Mn0.8O3 perovskite have been studied using Bean-Rodbell model. The Brillouin function allows determining the total momentum J and the mean filed exchange parameter λ of the perovskite. The mean-filed equation draws the system to second order phase transition. These constants were used to stimulate the experimental isotherms M (H, T) by meanfield theory. The predicted results are compared to the available experimental data. It is noted that a good agreement has been found, with minor discrepancies, between theoretical and experimental data.

Electron transport properties of InP

1980 ◽  
Vol 58 (7) ◽  
pp. 923-930 ◽  
Author(s):  
H. J. Lee ◽  
J. Basinski ◽  
L. Y. Juravel ◽  
J. C. Woolley
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Thermoelectric Power ◽  
Room Temperature ◽  
Theoretical Calculations ◽  
Scattering Parameters ◽  
Electron Transport Properties ◽  
Predicted Values ◽  
Experimental Values ◽  
Good Agreement

Measurements of electrical conductivity σ and Hall coefficient RH have been made as a function of temperature in the range room temperature to 250 °C and as a function of magnetic field up to 3.2 T on single crystal n-type samples of InP with carrier concentrations in the range 3.5 × 1021 to 1.2 × 1024 m−3. Theoretical calculations of σ and RH have been made using the method of Fletcher and Butcher and the resulting values fitted to the experimental data by using various scattering parameters as adjustable. The parameters so obtained have then been used to predict further magnetoresistance values and values of thermoelectric power and Nernst–Ettingshausen coefficient. The predicted values of magnetoresistance and thermoelectric power show good agreement with experimental values but not those of the Nernst–Ettingshausen coefficient, possibly due to experimental problems.

Fracture Mechanisms in SiC-Whisker Reinforced Alumina

1988 ◽  
Vol 120 ◽  
Author(s):  
Christophe H. Boulanger ◽  
Yih-Cherng Chiang ◽  
Azar P. Majidi ◽  
Tsu-Wei Chou
Keyword(s):  
Experimental Data ◽  
Fracture Toughness ◽  
Room Temperature ◽  
Crack Deflection ◽  
Fracture Mechanisms ◽  
Alumina Composite ◽  
Good Agreement

AbstractThe fracture mechanisms involved in the toughening of alumina by whisker reinforcement are studied at room temperature. The fracture toughness of a hot pressed SiC-whisker/alumina composite is measured and good agreement is found between the experimental data and a model that takes into account the effects of crack deflection and whisker pullout mechanisms. From the model, it is seen that the role of whisker pullout is negligible compared to that of crack deflection.

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