Curvature Measurements of Tri-Material Structures Under Thermal Excursion

1991 ◽  
Vol 226 ◽  
Author(s):  
Guo-Quan Lu ◽  
Boris Mogilevsky ◽  
Tapan K. Gupta
Keyword(s):  
Thermal Expansion ◽  
Elastic Modulus ◽  
Temperature Dependence ◽  
The Other ◽  
Thermal Expansion Mismatch ◽  
Ceramic Substrates ◽  
Die Attach ◽  
Curvature Measurements ◽  
Thermal Excursion

AbstractThe bending curvatures of tri-material plates have been measured using in situ laser reflection technique at temperatures ranging from 20°C to 160°C. The tri-material structures are formed by attaching silicon wafers to ceramic substrates with die-attach adhesives from solder-like (elastic modulus ≈ 24 GPa) to gel-like (elastic modulus ≈ 0.003 GPa) characteristics. The temperature dependence of curvature as a result of the thermal expansion mismatch is measured. The structure bonded by the gel-like adhesive has substantially lower, about a factor of ten less, bending than the structures attached by the other two types of adhesives. We found good agreements between the measurements and the theoretical derivations by Suhir[1] for the bending curvature of finite tri-material assembly.

In situ degradation studies of two-dimensional WSe2–graphene heterostructures

Nanoscale ◽  
2015 ◽  
Vol 7 (34) ◽  
pp. 14489-14495 ◽  
Author(s):  
B. Wang ◽  
S. M. Eichfield ◽  
D. Wang ◽  
J. A. Robinson ◽  
M. A. Haque
Keyword(s):  
Thermal Expansion ◽  
Thermal Degradation ◽  
Systematic Study ◽  
Two Dimensional ◽  
Thermal Expansion Mismatch ◽  
Two Dimensional Materials ◽  
Interfacial Defects ◽  
In Situ Degradation ◽  
Degradation Studies

Heterostructures of two-dimensional materials can be vulnerable to thermal degradation due to structural and interfacial defects as well as thermal expansion mismatch, yet a systematic study does not exist in the literature.

scholarly journals Patterns of sarcomere activation, temperature dependence, and effect of ryanodine in chemically skinned cardiac fibers.

1986 ◽  
Vol 87 (6) ◽  
pp. 885-905 ◽  
Author(s):  
A Lundblad ◽  
H Gonzalez-Serratos ◽  
G Inesi ◽  
J Swanson ◽  
P Paolini
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Temperature Dependence ◽  
Calcium Release ◽  
Contractile Activity ◽  
The Other ◽  
Calcium Blockers ◽  
Calcium Accumulation ◽  
Contractile Activation

Functionally skinned and electrochemically shunted myocytes were prepared by perfusing rat hearts with collagenase in order to obtain a technically improved measurement of sarcomere dynamics and to evaluate the role of sarcoplasmic reticulum in situ with respect to contractile activation. In the presence of micromolar calcium, the myocytes exhibited phasic and propagated contraction waves beginning at one end and proceeding along the myocyte. Beating rates, the propagation velocity of the activation wave, and single sarcomere shortening and relaxation velocities were obtained by manual or automated analysis of 16-mm film recorded at 170 frames/s from a camera attached to a microscope that was equipped with a temperature-controlled stage. In parallel experiments, calcium accumulation by the sarcoplasmic reticulum of the myocytes in situ was measured by direct isotopic tracer methods. The frequency (10-38 min-1) of spontaneous contractions, the velocity (1.9-7.4 microns . s-1) of sarcomere shortening, and the velocity (1.7-6.8 microns . s-1) of sarcomere relaxation displayed identical temperature dependences (Q10 = 2.2), which are similar to that of the calcium pump of sarcoplasmic reticulum and are consistent with a rate limit imposed by enzyme-catalyzed mechanisms on all these parameters. On the other hand, the velocity (77-159 microns . s-1) of sequential sarcomere activation displayed a lower temperature dependence (Q10 = 1.5), which is consistent with a diffusion-limited and self-propagating release of calcium from one sarcomere to the other. The phasic contractile activity of the dissociated myocytes was inhibited by 10(-8)-10(6) M ryanodine (and not by myolemmal calcium blockers) under conditions in which calcium accumulation by sarcoplasmic reticulum in situ was demonstrated to proceed optimally. The effect of ryanodine is attributed to an interaction of this drug with sarcotubular structures, producing inhibition of calcium release from the sarcoplasmic reticulum. The consequent lack of sarcomere activation underlines the role of sarcoplasmic reticulum uptake and release in the phasic contractile activation of the electrochemically shunted myocytes.

Different Temperature Dependencies of Magnetic Interface and Volume Anisotropies in Gd / W(110)

1995 ◽  
Vol 384 ◽  
Author(s):  
M. Farle ◽  
B. Schulz ◽  
A. Aspelmeier ◽  
G. Andre ◽  
K. Baberschke
Keyword(s):  
Film Thickness ◽  
Magnetic Anisotropy ◽  
Temperature Dependence ◽  
Ferromagnetic Resonance ◽  
Magnetocrystalline Anisotropy ◽  
The Other ◽  
Spin Interaction ◽  
Reduced Temperature ◽  
Thickness Independent

ABSTRACTThe magnetic anisotropy of epitaxial Gd(0001) films on W(110) is determined as a function of temperature (150 to 350 K) and film thickness (9 to 30 monolayers) by in situ ferromagnetic resonance. It is found that the usual analysis in terms of a thickness independent part KV and a thickness dependent contribution 2KS/d must be performed at the same reduced temperature t = T/Tc(d). Kv shows qualitatively the same temperature dependence as the magnetocrystalline anisotropy of bulk Gd. It changes in sign near 0.7 Tc and does not vanish at Tc. KS on the other hand decreases linearly from 1.2 meV/atom at 0.6.Tc to zero at Tc. It appears that the intrinsic origin for Kv and KS is fundamentally different. The vanishing of KS at Tc indicates that two-ion anisotropy (spin-spin interaction) is dominating the interface anisotropy. The non- zero KV(T≥Tc) is likely due to a single ion magnetic anisotropy which is known for bulk Gd.

scholarly journals Electronic-Excitation-Induced Processing in GaSb Compound Nanoparticles

2011 ◽  
Vol 2011 ◽  
pp. 1-4 ◽  
Author(s):  
H. Yasuda ◽  
H. Mori
Keyword(s):  
Temperature Dependence ◽  
Point Defects ◽  
Structural Changes ◽  
Electronic Excitation ◽  
The Other ◽  
Two Phase ◽  
Electron Dose ◽  
Total Electron ◽  
Transmission Electron

Temperature dependence of electronic-excitation-induced structural changes in nanoparticles has been studied by in situ transmission electron microscopy. When GaSb nanoparticles kept at 340 K were excited by 25 keV electrons, the compound transforms to the porous compound or the two-phase structure consisting of an antimony core and a gallium shell with increasing the total electron dose. On the other hand, in GaSb nanoparticles kept at 293 K the structure remains the original compound phase. It is suggested that such temperature dependence of the structural changes may arise from synergetic behaviors of point defects introduced athermally by the excitation and thermal mobility.

The effect of radiation-induced segregation on void swelling in electron-irradiated austenitic Fe-Cr-Ni-Ti-P Alloy

1990 ◽  
Vol 48 (4) ◽  
pp. 932-933
Author(s):  
H. Watanabe ◽  
T. Muroga ◽  
N. Yoshida
Keyword(s):  
Temperature Dependence ◽  
Electron Irradiation ◽  
Irradiation Temperature ◽  
The Other ◽  
Austenitic Steels ◽  
Nickel Concentration ◽  
In Situ Observation ◽  
Void Swelling ◽  
Radiation Induced

It has been reported that the void swelling in austenitic steels at higher temperatures is enhanced by a nickel depletion in matrix . The objective of the present study is to understand the effect of solute addition on void swelling, in association with microchemical changes, in austenitic steels during electron irradiation.Four types of model alloys (Fe-16Cr-17Ni, Fe-16Cr-17Ni-0.25Ti, Fe- 16Cr-17Ni-0.1P, Fe-16Cr-17Ni-0.25Ti-0.IP) and JPCA-2 were used in this study. Irradiation and in-situ observation were carried out with 1.0 MeV electrons utilizing JEM-1000 of HVEM Lab. Kyushu Univ.Fig. 1 shows the irradiation temperature dependence of nickel concentration in matrix after irradiated at 2 dpa. The ternary alloy and alloys containing phosphorus(or titanium) only show a strong nickel depletion in matrix due to nickel segregation to defect sinks. Our previous results about void swelling in these alloys showed that the temperature, where nickel depletion in matrix became prominent, corresponded to that of maxium void swelling. On the other hand, void swelling and the nickel depletion were not detected in Fe-16Cr-17Ni-0.25Ti-0.IP and JPCA-2.

Microstructural and Microchemical Characterization of Nickel Sulfide Inclusions in Plate Glass

1991 ◽  
Vol 49 ◽  
pp. 962-963
Author(s):  
J. Cooper ◽  
O. Popoola ◽  
W. M. Kriven
Keyword(s):  
Thermal Expansion ◽  
Phase Transformation ◽  
Glass Matrix ◽  
Nickel Sulfide ◽  
Plate Glass ◽  
Thermal Expansion Mismatch ◽  
Volume Increase ◽  
Β Phase ◽  
Microchemical Characterization

Nickel sulfide inclusions have been implicated in the spontaneous fracture of large windows of tempered plate glass. Two alternative explanations for the fracture-initiating behaviour of these inclusions have been proposed: (1) the volume increase which accompanies the α to β phase transformation in stoichiometric NiS, and (2) the thermal expansion mismatch between the nickel sulfide phases and the glass matrix. The microstructure and microchemistry of the small inclusions (80 to 250 μm spheres), needed to determine the cause of fracture, have not been well characterized hitherto. The aim of this communication is to report a detailed TEM and EDS study of the inclusions.

A very rapid in situ Kikuchi technique to determine relative crystal misorientation

1988 ◽  
Vol 46 ◽  
pp. 830-831
Author(s):  
J. I. Bennetch
Keyword(s):  
Electron Beam ◽  
Analytical Techniques ◽  
Superplastic Forming ◽  
The Other ◽  
Kikuchi Pattern ◽  
Kikuchi Line ◽  
Line Analysis

In a recent study of the superplastic forming (SPF) behavior of certain Al-Li-X alloys, the relative misorientation between adjacent (sub)grains proved to be an important parameter. It is well established that the most accurate way to determine misorientation across boundaries is by Kikuchi line analysis. However, the SPF study required the characterization of a large number of (sub)grains in each sample to be statistically meaningful, a very time-consuming task even for comparatively rapid Kikuchi analytical techniques.In order to circumvent this problem, an alternate, even more rapid in-situ Kikuchi technique was devised, eliminating the need for the developing of negatives and any subsequent measurements on photographic plates. All that is required is a double tilt low backlash goniometer capable of tilting ± 45° in one axis and ± 30° in the other axis. The procedure is as follows. While viewing the microscope screen, one merely tilts the specimen until a standard recognizable reference Kikuchi pattern is centered, making sure, at the same time, that the focused electron beam remains on the (sub)grain in question.

Temperature Dependence of Double Shockley Stacking Fault Behavior in Nitrogen-Doped 4h-Sic Studied by In-Situ Synchrotron X-Ray Topography

2020 ◽  
Author(s):  
Fumihiro Fujie ◽  
Shunta Harada ◽  
Kenji Hanada ◽  
Hiromasa Suo ◽  
Haruhiko Koizumi ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Stacking Fault ◽  
X Ray ◽  
Nitrogen Doped ◽  
Fault Behavior

scholarly journals Phase Transition and Coefficients of Thermal Expansion in Al2−xInxW3O12 (0.2 ≤ x ≤ 1)

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4021
Author(s):  
Andrés Esteban Cerón Cerón Cortés ◽  
Anja Dosen ◽  
Victoria L. Blair ◽  
Michel B. Johnson ◽  
Mary Anne White ◽  
...  
Keyword(s):  
Phase Transition ◽  
Thermal Expansion ◽  
Thermal Shock ◽  
Monoclinic Phase ◽  
Ceramic Materials ◽  
Precipitation Method ◽  
Scanning Calorimetry ◽  
Orthorhombic Crystal ◽  
Co Precipitation

Materials from theA2M3O12 family are known for their extensive chemical versatility while preserving the polyhedral-corner-shared orthorhombic crystal system, as well as for their consequent unusual thermal expansion, varying from negative and near-zero to slightly positive. The rarest are near-zero thermal expansion materials, which are of paramount importance in thermal shock resistance applications. Ceramic materials with chemistry Al2−xInxW3O12 (x = 0.2–1.0) were synthesized using a modified reverse-strike co-precipitation method and prepared into solid specimens using traditional ceramic sintering. The resulting materials were characterized by X-ray powder diffraction (ambient and in situ high temperatures), differential scanning calorimetry and dilatometry to delineate thermal expansion, phase transitions and crystal structures. It was found that the x = 0.2 composition had the lowest thermal expansion, 1.88 × 10−6 K−1, which was still higher than the end member Al2W3O12 for the chemical series. Furthermore, the AlInW3O12 was monoclinic phase at room temperature and transformed to the orthorhombic form at ca. 200 °C, in contrast with previous reports. Interestingly, the x = 0.2, x = 0.4 and x = 0.7 materials did not exhibit the expected orthorhombic-to-monoclinic phase transition as observed for the other compositions, and hence did not follow the expected Vegard-like relationship associated with the electronegativity rule. Overall, compositions within the Al2−xInxW3O12 family should not be considered candidates for high thermal shock applications that would require near-zero thermal expansion properties.

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