scholarly journals The effect of temperature on the intensity of X-ray reflexion

1947 ◽  
Vol 188 (1015) ◽  
pp. 509-521 ◽  
Keyword(s):  
Coefficient Of Thermal Expansion ◽  
Characteristic Temperature ◽  
Lattice Parameter ◽  
Effect Of Temperature ◽  
Special Method ◽  
Foreign Material ◽  
Powder Specimen ◽  
X Ray ◽  
Characteristic Temperatures ◽  
Different Temperatures

The effect of temperature on the intensity of X-ray reflexion by gold, copper and aluminium has been studied by making microphotometric measurements on lines in X-ray structure spectra obtained with powder specimens in a Debye-Scherrer camera. A special method was employed to make cylindrical powder specimens, 0.8 mm. in diameter, which held together without adhesive and were free from a core of foreign material. The primary beam was standardized by means of a flat-plate X-ray camera, furnished with a plate of powdered gold which provided a spectrum whose lines could be accurately measured. The powder specimen under investigation was maintained in vacuo at temperatures ranging up to about 900° K, and its temperature estimated from lattice parameter measurements. The observed fall in intensity of X-ray reflexion by gold and copper as the temperature is raised up to about 900° K can be accounted for if the characteristic temperature varies with temperature in accordance with the relation θ T = θ 1 [1 ─ αγ( T ─ T 1 )], where θ T and θ 1 are the characteristic temperatures at temperatures T and T 1 , α is the cubical coefficient of thermal expansion and γ is the Grȕneisen constant. This relation is found to hold also for aluminium up to about 600° K. Beyond 600° K the fall of intensity exceeds that to be expected from the above relation, and it is suggested that another factor becomes prominent in the case of aluminium at the higher temperatures. The characteristic temperatures of gold, copper and aluminium now found by X-ray measurement at different temperatures, agree with the values obtained at those temperatures by specific heat and electrical conductivity methods.

SIZE-INDUCED EFFECTS IN NANOSTRUCTURED NiFe2O4

2010 ◽  
Vol 24 (30) ◽  
pp. 5973-5985
Author(s):  
M. GUNES ◽  
H. GENCER ◽  
T. IZGI ◽  
V. S. KOLAT ◽  
S. ATALAY
Keyword(s):  
Electron Microscopy ◽  
Annealing Temperature ◽  
Structural Parameters ◽  
Hydrothermal Process ◽  
Lattice Parameter ◽  
Effect Of Temperature ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

NiFe 2 O 4 nanoparticles were successfully prepared by a hydrothermal process, and the effect of temperature on them was studied. The particles were annealed at various temperatures ranging from 413 to 1473 K. Studies were carried out using powder X-ray diffraction, scanning electron microscopy, infrared spectroscopy, differential thermal analysis, thermogravimetric analysis and a vibrating sample magnetometer. The annealing temperature had a significant effect on the magnetic and structural parameters, such as the crystallite size, lattice parameter, magnetization and coercivity.

X-Ray Diffraction by Compressed Solid Argon

1973 ◽  
Vol 51 (1) ◽  
pp. 25-35 ◽  
Author(s):  
P. M. Bronsveld ◽  
S. K. Kumra ◽  
J. C. Stryland
Keyword(s):  
Triple Point ◽  
Pressure Vessel ◽  
Coefficient Of Thermal Expansion ◽  
Volume Density ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rotation Method ◽  
Solid Argon ◽  
Oscillation Method

A technique is described to perform precision measurements of the lattice parameter of solid argon under pressure. Details are given of the apparatus which consists of a beryllium pressure vessel, a liquid nitrogen cryostat, a two-circle goniometer, and a cylindrical camera. Small argon crystals are grown in the pressure vessel and one suitable crystal is selected and correctly oriented with a precision of 1 min of arc, using the oscillation method. The single-crystal rotation method is used to measure the lattice parameter with an estimated precision of 0.01%. Measurements were carried out along the melting line in the range from the triple point (83.8 K and 0.7 bar) to 95 K and 450 bar. The result obtained for the lattice parameter of solid argon near the triple point, a0 = 5.4676 ± 0.0005 Å, is in close agreement with the low pressure result of Peterson et al. Some values are calculated for the molar volume, density, coefficient of thermal expansion, and bulk modulus of solid argon, and these results are compared with those obtained by other workers using different methods.

Elucidating Structural Mechanisms for Cordierite Ceramic Formation using Synchrotron Radiation

1993 ◽  
Vol 307 ◽  
Author(s):  
Menno Oversluizen ◽  
S. M. Clark ◽  
G. N. Greaves
Keyword(s):  
Synchrotron Radiation ◽  
Spinel Phase ◽  
Average Energy ◽  
Nucleating Agent ◽  
Lattice Parameter ◽  
Oxide Glasses ◽  
X Ray ◽  
Different Temperatures ◽  
Diffraction Patterns ◽  
Prolonged Heat

ABSTRACTCr2O3 is a common nucleating agent useful for forming ceramics from oxide glasses. In this study we have used a variety of synchrotron radiation techniques to examine the atomic structure, crystallinity and microstructure of a magnesium alumino-silicate glass ceramic whose composition is close to that of the mineral cordierite, Mg2Al4Si5O13. X-ray Absorption spectra on the Cr K-edge have been performed with samples that were heat treated at different temperatures and times to examine the metamorphosis of the nucleating site. This study reveals that Cr3+ is always octahedrally coordinated with oxygen. In addition, the second nearest neighbour environment changes from an amorphous, single shell of Al/Si, but upon crystallisation, develops into a well ordered Al/Mg shell indicative of the formation of a dilute Cr spinel phase. Powder X-ray Diffraction (XRD) patterns, however, reveal that the major phase initially precipitated (˜900°C) is a stuffed quartz and from the lattice parameters that the composition is SiO2 -rich. With prolonged heat treatment a small quantity of a spinel phase emerges whose composition from its lattice parameter is close to MgAl2O4. Combined Small Angle X-ray Scattering (SAXS) and XRD establish that devitrification at these temperatures is associated with particles about 250 Å in size, on average. Energy dispersive powder diffraction patterns were collected in situ to observe changes in crystallinity with temperature and time. From these measurements the stuffed quartz phase identified at 900°C is found to be intermediate, being eventually replaced at higher temperatures by cordierite with a small quantity of spinel.

OPTICAL AND STRUCTURAL PROPERTIES OF Ag NANOPARTICLES Eu OXIDE FILMS

2008 ◽  
Vol 07 (06) ◽  
pp. 339-344 ◽  
Author(s):  
A. A. DAKHEL
Keyword(s):  
Lattice Parameter ◽  
Europium Oxide ◽  
Silicon Substrates ◽  
Ag Nanoparticle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nanoparticle Radius ◽  
Different Temperatures ◽  
Bcc Structure ◽  
The Eu

Silver-incorporated europium oxide thin films have been prepared by the successive evaporation method on quartz and silicon substrates. The silver concentration was 2.5% and 8.9% respectively, as measured by X-ray fluorescence. X-ray diffraction revealed that the Eu oxide of these samples remained amorphous after preannealing at 450°C; however, it crystallized in bcc structure at 800°C. The lattice parameter of the crystallized Eu oxide was larger than that of the bulk, due to the adsorption of Ag + ions, which have a higher ionic radius. The optical absorption of the samples manifested the surface plasmon resonance (SPR) phenomenon, which varied with the Ag content and preannealings of the samples at different temperatures. The Ag nanoparticle radius was estimated with the Mie classical theory by using the SPR data analysis.

Design of temperature-immunization system packaging for the resonant pressure sensor

2017 ◽  
Vol 31 (08) ◽  
pp. 1750085 ◽  
Author(s):  
Anlin Li ◽  
Chenying Zhang ◽  
Huan Wang ◽  
Yong He ◽  
Daoheng Sun ◽  
...  
Keyword(s):  
Resonant Frequency ◽  
Temperature Sensitivity ◽  
Pressure Sensor ◽  
Coefficient Of Thermal Expansion ◽  
Effect Of Temperature ◽  
Element Simulation ◽  
Different Temperatures ◽  
Time Changes ◽  
Packaging Structure ◽  
System Packaging

Based on the study of the material matching and structure cooperating, this paper mainly explores a new packaging structure with low thermal mismatches which can enhance the accuracy and stability of the resonant pressure sensor. According to the finite element simulation, the rule of the coefficient of thermal expansion (CTE) and the depth of the groove on the substrate, which has an influence on the temperature sensitivity, could be obtained. By analyzing the effect of temperature on the resonant frequency, it shows the temperature sensitivity of the new packaging structure is −0.97 Hz/[Formula: see text]C in 20 kPa, under the temperature range of 30[Formula: see text]C to 80[Formula: see text]C. After analyzing resonant frequency stability at different temperatures, it is found that the time for achieving stability at different temperatures of the new packaging structure is at least 10 min less than that of TO packaging structure. The average frequency’s relative variation ratio of the new packaging structure at different temperatures remains roughly the same, and the variation range is within ±[Formula: see text]0.005% as time changes. These results indicate that the new packaging structure has the characteristic of great temperature-immunization.

Synthesis of Copper and Lithium Copper Ferrites as High Magnetization Materials

2000 ◽  
Vol 15 (7) ◽  
pp. 1635-1641 ◽  
Author(s):  
K. E. Kuehn ◽  
D. Sriram ◽  
S. S. Bayya ◽  
J. J. Simmins ◽  
R. L. Snyder
Keyword(s):  
Low Temperature ◽  
Site Occupancy ◽  
Lattice Parameter ◽  
Copper Ferrite ◽  
Slow Cooling ◽  
Magnetization Measurements ◽  
X Ray ◽  
Different Temperatures ◽  
Solution Region ◽  
Pure Cu

The ferrite with composition Cu0.5Fe2.5O4 was heat treated in air and in reducing atmospheres to different temperatures within the solid solution region confirmed by dynamic high-temperautre x-ray characterization. The samples were quenched in oil and air, and lattice parameter, Curie temperature, and saturation magnetization measurements were completed. The magnetization measurements for these samples showed a maximum 4πMs of 0.7729 and 0.5426 T at 10 and 300 K, respectively. The cationic distribution based on the low-temperature 4πMs measurements is (Cu+0.24Fe3+0.76)A[Cu+0.26Fe3+1.74]BO4 → 4.9 µ B. X-ray-pure Cu0.5Fe2.5O4 samples were also synthesized by slow cooling from the formation temperature to 900 °C in a reducing atmosphere. A temperature–PO2 diagram for the stability of Cu0.5Fe2.5O4 under the conditions of the experiment was determined. Low-temperature 4πMs measurements did not indicate an increase in the Cu+ A site occupancy for the samples cooled to 900 °C in a reducing environment above those samples that were quenched from high temperature. Curie temperatures for all Cu0.5Fe2.5O4 samples ranged from 348 to 369 °C. Lithium additions (0.1 mol/unit formula) to copper ferrite Li0.1Cu0.4Fe2.5O4 decreased the room-temperature 4πMs values to 0.5234 T with a corresponding decrease in the 10 K measurements to 0.7047 T. From the low-temperature magnetization measurements, the distribution was (Cu+0.15Fe3+0.85)A[Cu+0.25Li+0.1Fe3+1.65]BO4 → 4.48 µ B.

Preparations of Hydroxyapatite from Tilapia Scales

2015 ◽  
Vol 1087 ◽  
pp. 30-34 ◽  
Author(s):  
KANAGESWARY SOCKALINGAM ◽  
Mohd Azha Yahya ◽  
Hasan Zuhudi Abdullah
Keyword(s):  
Calcination Temperature ◽  
Thermo Gravimetric Analysis ◽  
Weight Ratio ◽  
Xrd Analysis ◽  
Effect Of Temperature ◽  
Gravimetric Analysis ◽  
Fish Scale ◽  
X Ray ◽  
Isolation And Characterization ◽  
Different Temperatures

Hydroxyapatite (HAp), classified as bioceramic materials is the major mineral constituent of vertebrate bones and teeth. In this study, the effect of temperature on isolation and characterization of HAp from tilapia fish scales have been investigated. Scales were subjected to heat treatment at different temperatures (800°C and 1000°C) and microstructure of both raw and calcined scales were observed under Scanning Electron Microscopy (SEM). Thermo Gravimetric Analysis (TGA) and Energy Dispersive X-Ray Spectroscopy (EDX) results have revealed the best calcination temperature of tilapia scales to be 800°C due to the calculated calcium to phosphorous weight ratio (Ca/P). The Ca/P ratio for scales treated at 800°C and 1000°C were 1.598 and 1.939 respectively. The phase purity and crystallinity of produced HAp was further confirmed by X-Ray Diffraction (XRD) analysis. Based on the study, it can be concluded that tilapia fish scale is a good natural source of HAp with 800°C as the optimum calcination temperature in HAp production.

Effect of Growth Temperature on the Indium Incorporation in InGaN Epitaxial Films

2011 ◽  
Vol 287-290 ◽  
pp. 1456-1459 ◽  
Author(s):  
P. C Chang ◽  
C. L Yu ◽  
Y. W Jahn ◽  
S. J Chang ◽  
K. H Lee
Keyword(s):  
Optoelectronic Devices ◽  
Chemical Vapor ◽  
Epitaxial Films ◽  
Effect Of Temperature ◽  
X Ray Diffraction ◽  
Film Properties ◽  
X Ray ◽  
Different Temperatures ◽  
Peak Emission

InxGa1-xN epilayers have been grown by metalorganic chemical vapor deposition (MOCVD) at different temperatures between 740°C to 830°C. The thickness of InGaN film is 50nm for all samples. The incorporation of indium is found to increase with decreasing grown temperature. The optical properties and film quality of the samples have been investigated by photoluminescence (PL) system and X-ray diffraction (XRD). The Full Width at Half Maximum (FWHM) of PL and XRD decreases with increasing the grown temperature. We also found that the peak emission of PL shifts with changing the grown temperature. The effect of temperature on the film properties was determined. This understanding will lead to better quality control of the optoelectronic devices.

Determination Of Temperature Dependent Unstressed Lattice Spacings In Crystalline Thin Films On Substrates

1997 ◽  
Vol 505 ◽  
Author(s):  
G. Cornella ◽  
S. Lee ◽  
O. Kraft ◽  
W. D. Nix ◽  
J. C. Bravman
Keyword(s):  
Thin Films ◽  
Thermal Expansion ◽  
Coefficient Of Thermal Expansion ◽  
Strain Analysis ◽  
Lattice Parameter ◽  
Gold Films ◽  
Sample Material ◽  
Temperature Dependent ◽  
X Ray

ABSTRACTX-ray strain analysis via Generalized Focusing Diffractometry (GFD) [1], and the concurrent need for accurate values of the unstrained lattice parameter, are discussed. A new method for determining the unstrained lattice parameter without knowledge of the elastic constants of the sample material is described. Stress measurements at varying temperatures, and extraction of the coefficient of thermal expansion from these measurements, are demonstrated for aluminum and gold films.

scholarly journals The estimation of the parameter Gruneisen metal hexaborides

2018 ◽  
Vol 20 (90) ◽  
pp. 36-39
Author(s):  
Y. Fedyshyn ◽  
D. Vadets ◽  
O. Garashchenko ◽  
O. Romanov ◽  
T. Fedyshyn
Keyword(s):  
High Temperature ◽  
Molar Volume ◽  
Characteristic Temperature ◽  
Mathematical Expression ◽  
Crystalline Lattice ◽  
Grüneisen Parameter ◽  
X Ray ◽  
Volumetric Expansion ◽  
Different Temperatures ◽  
Implicit And Explicit

The basis for the estimation of the Gruneisen parameter γ is laid  (θД – Debye’s characteristic temperature, V– molar volume) from which the mathematical expression follows . In previous publications in order to determine θД the Lindemann formula was used. However, due to the ambiguity of the dimensional coefficient C in the Lindemann formula, the authors used the method of high-temperature roentgenography within the limits of 293–973 K. On the basis of analisys of the intensity of one maximum interference (hkl) at different temperatures, was determined by Chipman’s method X-ray characteristic temperature  θр(Т) groups of hexaboard type CaB6, namely CaB6, YB6, LaB6, CeB6, PrB6 , NdB6, ErB6, ThB6, YbB6. Considering, that neither the structure nor the interatomic connections within the temperature search of hexaborides does not change, the value of the parameter γ is determined. Its value was obtained within 2.5–4.7 for CeB6, NdB6, ErB6, YbB6, ThB6 and order 5.5–6.6 for CaB6, YB6, LaB6, PrB6. The parameters of Gruneisen proved to be practically independent of temperature. The presence of the meanings of γ made it possible to divide the implicit and explicit parts of the anagrammonism into a calming measure. The generalizing measure of anharmonism is mainly exhausted by the product γβ (β – the coefficient of the volumetric expansion of the crystalline lattice.

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