Studying Mechanical Properties Of Thin Films Under High Pressures

ABSTRACTWork-hardening curves of aluminum foils and of stacks of O.1μm thick 22 ct. gold foils, deformed between rotating Bridgman anvils, have been obtained for pressures up to 1533 MPa and shear strains to 400,000%. No sample thickness effect has been found between 5μm and 3μm, nor any significant difference between homogeneous foils and multi-layer foils, but heat-treatments do affect the results, as apparently does the introduction of 50nm thick sputtered copper layers between stacks of gold foils. Increases of strength with pressure appear to be due to corresponding increases of the Peierls-Nabarro stress. X-ray evidence indicates the reorientation of the foils from an initial (001) recrystallization texture after rolling to the (111) texture that was to be expected. Ordinary deformation behavior is indicated throughout, except for a tendency for slight negative work-hardening in the lower pressure range. At the extreme, assuming homogeneous deformation, the foils thinned to 60nm.

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Distensibility of small veins of the dog lung

Journal of Applied Physiology ◽

10.1152/jappl.1992.73.5.2158 ◽

1992 ◽

Vol 73 (5) ◽

pp. 2158-2165 ◽

Cited By ~ 7

Author(s):

A. al-Tinawi ◽

A. V. Clough ◽

D. R. Harder ◽

J. H. Linehan ◽

D. A. Rickaby ◽

...

Keyword(s):

Vascular Resistance ◽

Negative Correlation ◽

Pressure Range ◽

High Pressures ◽

X Ray ◽

Average Value ◽

Isolated Lung ◽

Weak Negative Correlation ◽

Intravascular Pressure ◽

Lung Lobes

To determine the distensibility of the intrapulmonary veins (250–2,900 microns diam) of the dog lung, we obtained X-ray angiograms from isolated lung lobes over a vascular pressure range of approximately 0–30 Torr. Over this pressure range the diameter vs. pressure curves tended to flatten out at the high pressures. In the pressure range of 0–19 Torr, we characterized the vessel distensibility by alpha (the ratio of the slope, beta, of the graph of diameter vs. intravascular pressure to the intercept, Do). The average value of alpha was approximately 1.2%/Torr. There was a weak negative correlation (r = -0.32) between alpha and Do. Infusion of enough norepinephrine to produce approximately 50% increase in total lobar vascular resistance produced a decrease in Do and alpha of approximately 33 and 32%, respectively.

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Sample thickness effect of thermal vibration correction within X-ray dynamical theory for germanium-doped silicon

Journal of Applied Physics ◽

10.1063/1.4979307 ◽

2017 ◽

Vol 121 (12) ◽

pp. 125704 ◽

Cited By ~ 2

Author(s):

Zhen Li ◽

Johannes Will ◽

Peng Dong ◽

Deren Yang

Keyword(s):

Dynamical Theory ◽

Sample Thickness ◽

Thermal Vibration ◽

Thickness Effect ◽

X Ray ◽

Doped Silicon

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X-ray diffraction study of HgBa2CuO4+δ at high pressures

Powder Diffraction ◽

10.1017/s0885715600009544 ◽

1997 ◽

Vol 12 (2) ◽

pp. 106-112

Author(s):

Eduardo J. Gonzalez ◽

Winnie Wong-Ng ◽

Gasper J. Piermarini ◽

Christian Wolters ◽

Justin Schwartz

Keyword(s):

High Pressure ◽

Bulk Modulus ◽

Pressure Range ◽

High Pressures ◽

Anisotropy Ratio ◽

X Ray Diffraction ◽

X Ray ◽

Anisotropic Elastic ◽

High Pressure Study

An in situ high pressure study using energy dispersive X-ray diffraction has been carried out on the polycrystalline high-Tc superconductor, HgBa2CuO4+δ (Hg-1201), to study its phase stability under pressure and also to measure its compressibility and bulk modulus. No evidence of pressure-induced polymorphism was found in the pressure range investigated, i.e., from 0.1 MPa (1 atm) to 5 GPa. The compound exhibited anisotropic elastic properties. The axial compressibility along the c axis was measured to be (3.96±0.35)×10−3GPa−1 and along the a axis (3.42±0.13)×10−3GPa−1, corresponding to an anisotropy ratio of 1.16±0.11. The bulk modulus was determined to be (94.7±4.2) GPa and, assuming a Poisson's ratio of 0.2, Young's modulus was estimated to be (170±8) GPa.

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Tilting of semi-rigid GaF6 octahedra in GaF3 at high pressures

Powder Diffraction ◽

10.1017/s0885715616000701 ◽

2017 ◽

Vol 32 (S1) ◽

pp. S69-S73

Author(s):

Jens-Erik Jørgensen ◽

Yaroslav Filinchuk ◽

Vladimir Dmitriev

Keyword(s):

High Pressure ◽

Pressure Range ◽

High Pressures ◽

Sphere Packing ◽

Volume Reduction ◽

X Ray Diffraction ◽

X Ray ◽

Compression Mechanism ◽

Measured Pressure ◽

Linear Compressibility

The VF3-type compound GaF3 has been studied by high-pressure angle-dispersive X-ray diffraction in the pressure range from 0.0001 to 10 GPa. The compression mechanism was found to be highly anisotropic. The c-axis shows little pressure dependence (≈0.4%), but exhibits negative linear compressibility up to ≈3 GPa where it achieves its maximum length. In contrast, the length of the a-axis is reduced by ≈8.8% at the highest measured pressure and an anomalous reduction in the linear compressibility is observed at 4 GPa. The zero pressure bulk modulus B0 was determined to B0 = 28(1) GPa. The compression mechanism of GaF3 is discussed in terms of deformation of an 8/3/c2 sphere-packing model. The volume reduction of GaF3 is mainly achieved through coupled rotations of the GaF6 octahedra within the entire measured pressure range, which reduces the volume of the cubooctahedral voids. In addition, the volume of the GaF6 octahedra also decreases for p ≲ 4.0 GPa, but remains constant above this pressure. The volume reduction of the GaF6 octahedra is accompanied by an increasing octahedral strain. Isosurfaces of the procrystal electron density are used for visualization of the cubooctahedral voids at different pressures.

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Morphology and Structure of Oxides Grown on Aluminum In Superheated Steam

CORROSION ◽

10.5006/0010-9312-21.7.222 ◽

1965 ◽

Vol 21 (7) ◽

pp. 222-234 ◽

Cited By ~ 10

Author(s):

R. K. HART ◽

J. K. MAURIN

Keyword(s):

Electron Microscopy ◽

Pressure Range ◽

Superheated Steam ◽

High Pressures ◽

Pure Aluminum ◽

X Ray Diffraction ◽

X Ray ◽

Powder Product ◽

Morphology And Structure ◽

Products Of Reaction

Abstract Four methods (light microscopy, electron microscopy, electron diffraction and X-ray diffraction) have been employed to identify and estimate the-products of reaction of pure aluminum with steam; in a few instances gravimetric measurements were also made. At temperatures between 400 and 450 C (752 and 842 F) and intermediate to high pressures aluminum disintegrated to a white powder product within 6 hours. This powder product was a mixture of α- and γ-alumina together with a small amount of aluminum. At higher temperatures and over the whole pressure range only γ-alumina was formed. The morphology of this material was threefold. A thin, highly resistant film rapidly grew to approximately 300 Å and drastically slowed down the reaction process. Outcropping from this film were oxide crystallites between 0.1 and 1.0 micron in size, as well as thin platelets which grew out from the surface as much as 10 microns. After reaction, specimen surfaces were found to contain numerous gas blisters as well as pits of various shapes and sizes. These pits ranged in size from less than 1 micron up to 300 microns and were located at grain boundaries as well as within metal grains.

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Crystal structure of pimecrolimus Form B, C43H68ClNO11

Powder Diffraction ◽

10.1017/s088571562100004x ◽

2021 ◽

Vol 36 (1) ◽

pp. 35-42

Author(s):

Shivang Bhaskar ◽

Joseph T. Golab ◽

James A. Kaduk ◽

Amy M. Gindhart ◽

Thomas N. Blanton

Keyword(s):

Crystal Structure ◽

Powder Diffraction ◽

Density Functional ◽

Van Der Waals Interactions ◽

Powder Diffraction File ◽

X Ray ◽

Weak Intermolecular Interactions ◽

Significant Difference ◽

Atomic Coordinates ◽

Solid State Conformation

The crystal structure of pimecrolimus Form B has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional techniques. Pimecrolimus crystallizes in the space group P21 (#4) with a = 15.28864(7), b = 13.31111(4), c = 10.95529(5) Å, β = 96.1542(3)°, V = 2216.649(9) Å3, and Z = 2. Although there are an intramolecular six-ring hydrogen bond and some larger chain and ring patterns, the crystal structure is dominated by van der Waals interactions. There is a significant difference between the conformation of the Rietveld-refined and the DFT-optimized structures in one portion of the macrocyclic ring. Although weak, intermolecular interactions are apparently important in determining the solid-state conformation. The powder pattern is included in the Powder Diffraction File™ (PDF®) as entry 00-066-1619. This study provides the atomic coordinates to be added to the PDF entry.

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Integration of Dental Implants in Conjunction with EDTA-Conditioned Dentin Grafts: An Experimental Study

Dentistry Journal ◽

10.3390/dj9060063 ◽

2021 ◽

Vol 9 (6) ◽

pp. 63

Author(s):

Payam Farzad ◽

Ted Lundgren ◽

Adel Al-Asfour ◽

Lars Andersson ◽

Christer Dahlin

Keyword(s):

Direct Contact ◽

Mineral Content ◽

X Rays ◽

X Ray ◽

Dentin Surface ◽

Significant Difference ◽

C And N ◽

Micro Implants ◽

Demineralized Dentin

This study was undertaken to investigate the integration of titanium micro-implants installed in conjunction with previously dentin-grafted areas and to study the morphological appearance, mineral content, and healing pattern of xenogenic EDTA-conditioned dentin blocks and granules grafted to cavities in the tibial bone of rabbits. Demineralized and non-demineralized dentin blocks and granules from human premolars were implanted into cavities prepared on the lateral aspects of the tibias of rabbits. After a healing period of six months, micro-implants were installed at each surgical site. Histological examinations were carried out after 24 weeks. Characterization of the EDTA-conditioned dentin blocks was performed by means of light microscopy, dental X-rays, scanning electron microscopy, and energy dispersive X-ray analysis (EDX). No implants were found to be integrated in direct contact with the dentin particles or blocks. On the EDTA-conditioned dentin surface, the organic marker elements C and N dominated, as revealed by EDX. The hydroxyapatite constituents Ca and P were almost absent on the dentin surface. No statistically significant difference was observed between the EDTA-conditioned and non-demineralized dentin, as revealed by BIC and BA. The bone-inductive capacity of the dentin material seemed limited, although demineralization by means of EDTA indicated higher BIC and BA values in conjunction with the installed implants in the area. A 12 h EDTA treatment did not fully decalcify the grafts, as revealed by X-ray analysis.

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X-ray properties of He ii λ 1640 emitting galaxies in VANDELS

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa1805 ◽

2020 ◽

Vol 496 (3) ◽

pp. 3796-3807

Author(s):

A Saxena ◽

L Pentericci ◽

D Schaerer ◽

R Schneider ◽

R Amorin ◽

...

Keyword(s):

Formation Rate ◽

Galactic Nuclei ◽

X Ray ◽

Star Forming ◽

Set Constraints ◽

Significant Difference ◽

Low Metallicity ◽

Matched Samples ◽

X Ray Binaries

ABSTRACT We explore X-ray emission from a sample of 18 He ii λ1640 emitting star-forming galaxies at z ∼ 2.3–3.6 from the VANDELS survey in the Chandra Deep Field South, to set constraints on the role of X-ray sources in powering the He ii emission. We find that 4 He ii emitters have tentative detections with S/N ∼ 2 and have X-ray luminosities, LX = 1.5−4.9 × 1041 erg s−1. The stacked luminosity of all 18 He ii emitters is 2.6 × 1041 erg s−1, and that of a subset of 13 narrow He ii emitters (FHWM(He ii) < 1000 km s−1) is 3.1 × 1041 erg s−1. We also measure stacked LX for non-He ii emitters through bootstrapping of matched samples, and find LX = 2.5 × 1041 erg s−1, which is not significantly different from LX measured for He ii emitters. The LX per star formation rate for He ii emitters (log (LX/SFR) ∼ 40.0) and non-emitters (log (LX/SFR) ∼ 39.9) are also comparable and in line with the redshift evolution and metallicity dependence predicted by models. Due to the non-significant difference between the X-ray emission from galaxies with and without He ii, we conclude that X-ray binaries or weak or obscured active galactic nuclei are unlikely to be the dominant producers of He ii ionizing photons in VANDELS star-forming galaxies at z ∼ 3. Given the comparable physical properties of both He ii emitters and non-emitters reported previously, alternative He ii ionizing mechanisms such as localized low-metallicity stellar populations, Pop-III stars, etc. may need to be explored.

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Compressibility of β-As4S4: an in situ high-pressure single-crystal X-ray study

Mineralogical Magazine ◽

10.1180/minmag.2012.076.4.12 ◽

2012 ◽

Vol 76 (4) ◽

pp. 963-973 ◽

Cited By ~ 6

Author(s):

G. O. Lepore ◽

T. Boffa Ballaran ◽

F. Nestola ◽

L. Bindi ◽

D. Pasqual ◽

...

Keyword(s):

Pressure Range ◽

Substantial Reduction ◽

Structural Data ◽

Unit Cell ◽

Van Der Waals Interactions ◽

X Ray Diffraction ◽

Unit Cell Parameters ◽

X Ray ◽

Cell Parameters ◽

Intermolecular Distances

AbstractAmbient temperature X-ray diffraction data were collected at different pressures from two crystals of β-As4S4, which were made by heating realgar under vacuum at 295ºC for 24 h. These data were used to calculate the unit-cell parameters at pressures up to 6.86 GPa. Above 2.86 GPa, it was only possible to make an approximate measurement of the unit-cell parameters. As expected for a crystal structure that contains molecular units held together by weak van der Waals interactions, β-As4S4 has an exceptionally high compressibility. The compressibility data were fitted to a third-order Birch–Murnaghan equation of state with a resulting volume V0 = 808.2(2) Å3, bulk modulus K0 = 10.9(2) GPa and K' = 8.9(3). These values are extremely close to those reported for the low-temperature polymorph of As4S4, realgar, which contains the same As4S4 cage-molecule. Structural analysis showed that the unit-cell contraction is due mainly to the reduction in intermolecular distances, which causes a substantial reduction in the unit-cell volume (∼21% at 6.86 GPa). The cage-like As4S4 molecules are only slightly affected. No phase transitions occur in the pressure range investigated.Micro-Raman spectra, collected across the entire pressure range, show that the peaks associated with As–As stretching have the greatest pressure dependence; the S–As–S bending frequency and the As–S stretching have a much weaker dependence or no variation at all as the pressure increases; this is in excellent agreement with the structural data.

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