Crystal Growth of Aluminum Magnesium Borides from Al-Mg-B Ternary System Solutions and Properties of the Crystals

2004 ◽  
Vol 449-452 ◽  
pp. 365-368 ◽  
Author(s):  
Shigeru Okada ◽  
Kunio Kudou ◽  
T. Mori ◽  
Takaaki Shishido ◽  
I. Higashi ◽  
...  
Keyword(s):  
Crystal Growth ◽  
High Temperature ◽  
Ternary System ◽  
Low Temperatures ◽  
Oxidation Process ◽  
Anomalous Behavior ◽  
Optimum Conditions ◽  
Metallic Luster ◽  
Aluminum Metal ◽  
Metal Flux

Single crystals of AlMgB14and AlMgB22were grown from a high-temperature aluminum metal flux in an Ar atmosphere. The optimum conditions for growing AlMgB22and AlMgB14were established using the starting mixtures of B/Mg=0.5-1.0 and B/Mg=2.0-6.0. The AlMgB14and AlMgB22crystals obtained have well-developed {001} and {100} faces, and were black with a metallic luster. The maximum dimensions of these crystals were about 5.2 mm and 4.6 mm, respectively. The values of micro-Vickers hardness of the AlMgB14and AlMgB22crystals are in the ranges of 23.9±0.6-27.6±0.6 GPa. The oxidation process of AlMgB14and AlMgB22crystals were studied up to 1473 K by TG-DTA method. The susceptibility of AlMgB14 with an increase at low temperatures does not show any particular features, being indicative of a paramagnetic contribution, which is likely due to impurities. The susceptibility of the AlMgB22sample shows no apparent contribution from impurities and also does not have any anomalous behavior.

Oxidation Behavior of Amorphous Nano-Si3N4 Powders

2014 ◽  
Vol 602-603 ◽  
pp. 367-370 ◽  
Author(s):  
Jiang Bo Wen ◽  
Sheng Huang ◽  
Hong Jie Wang
Keyword(s):  
High Temperature ◽  
Partial Pressure ◽  
Mechanical Behavior ◽  
Low Temperatures ◽  
Traditional Method ◽  
Oxidation Behavior ◽  
Oxidation Process ◽  
Composite Ceramic ◽  
Intergranular Phase ◽  
Sintering Additives

The traditional method preparing Si3N4/Si2N2O composite ceramic is to sinter α-Si3N4 powder with additives at relatively high temperatures. But the intergranular phase transformed from the sintering additives can degrade the high-temperature mechanical behavior. Amorphous nanoSi3N4 is used to fabricate Si3N4/Si2N2O composite ceramic by its oxidation and nitridation without sintering additives at low temperatures. Thus, it is essential to study the oxidation behavior and mechanism of amorphous nanoSi3N4. Amorphous nanoSi3N4 powders were oxidized in different atmospheres, at varying temperatures and for various different length of time. The oxidation process and products was analyzed by means of XRD, TGA and FTIR. The results showed that amorphous nanoSi3N4 could be oxidized into SiO2 from 600°C to 1300°C. Below 1300°C, the oxidation became serious as the temperature increased. Besides, the longer the oxidation time and the lager the ratio of O2/N2 partial pressure was, the deeper the oxidation level was. When the temperature was above 1300°C, amorphous nanoSi3N4 was completely oxidized into SiO2.

Are Gel-Derived Glasses Different from Ordinary Glasses?

1986 ◽  
Vol 73 ◽  
Author(s):  
M. C. Weinberg
Keyword(s):  
Phase Transformation ◽  
Thermal Properties ◽  
High Temperature ◽  
Experimental Evidence ◽  
High Temperatures ◽  
Low Temperatures ◽  
Anomalous Behavior ◽  
Transformation Behavior ◽  
Gel Glasses ◽  
Very High

ABSTRACTA review is presented of some of the previously reported differences and similarities between comparable gel glasses (and gels) and ordinary glasses. In this regard, considerations are made with respect to such factors as structure, physical and thermal properties, and phase transformation behavior. A variety of silicate lass compositions are used for illustrative purposes. The discussion is roughly ivided into two sections; low and high temperature behavior. At low temperatures one anticipates that differences between gel and conventional glasses will exist, but such dissimilarities are not expected to persist to high temperatures. However, experimental evidence is presented which indicates the perpetuation of such differences to very high temperatures. A partial resolution for this anomalous behavior is offered.

Latch-Up Induced Slit Voiding in Aluminum Metal Lines

1999 ◽  
Author(s):  
Chunyu Zhang ◽  
Lakshmi Vedula ◽  
Shekhar Khandekar
Keyword(s):  
High Temperature ◽  
Line Width ◽  
Fold Increase ◽  
Metal Line ◽  
Operating Life ◽  
Mixed Signal ◽  
Aluminum Metal ◽  
Temperature Operating ◽  
Latch Up

Abstract Latch-up induced during High Temperature Operating Life (HTOL) test of a mixed signal device fabricated with 1.0 μm CMOS, double poly, double metal process caused failures due to an open in aluminum metal line. Metal lines revealed wedge voids of about 50% of the line width. Triggering of latch up mechanism during the HTOL test resulted in a several fold increase of current flowing through the ground metal line. This increase in current resulted in the growth of the wedge voids leading to failures due to open metal lines.

Crystallization of Isotactic Poly(propylene) in Solution as Followed by Slow Calorimetry

1995 ◽  
Vol 60 (11) ◽  
pp. 1905-1924 ◽  
Author(s):  
Hong Phuong-Nguyen ◽  
Geneviève Delmas
Keyword(s):  
Molecular Weight ◽  
Crystal Growth ◽  
High Temperature ◽  
Heat Of Fusion ◽  
Complete Dissolution ◽  
Polymer Molecular Weight ◽  
Solvent Quality ◽  
Temperature Ramp ◽  
Poly Propylene

Dissolution, crystallization and second dissolution traces of isotactic poly(propylene) have been obtained in a slow temperature ramp (3 K h-1) with the C80 Setaram calorimeter. Traces of phase-change, in presence of solvent, are comparable to traces without solvent. The change of enthalpy on heating or cooling, ∆Htotal, over the 40-170 °C temperature range, is the sum of two contributions, ∆HDSC and ∆Hnetwork. The change ∆HDSC is the usual heat obtained in a fast temperature ramp and ∆Hnetwork is associated with a physical network whose disordering is slow and subject to superheating due to strain. When dissolution is complete, ∆Htotal is equal to ∆H0, the heat of fusion of perfect crystals. The values of ∆Htota for nascent and recrystallized samples are compared. Dissolution is the tool to evaluate the quality of the crystals. The repartition of ∆Htotal, into the two endotherms, reflects the quality of crystals. The crystals grown more rapidly have a higher fraction of network crystals which are stable at high T in the solvents. A complete dissolution, i.e. a high temperature (170 °C or more) is necessary to obtain good crystals. The effect of concentration, polymer molecular weight and solvent quality on crystal growth is analyzed.

scholarly journals Dopants Modulate Crystal Growth in Molten Salts Enabled by Surface Energy Tuning

2021 ◽  
Author(s):  
Xiaoqiao Li ◽  
Linming Zhou ◽  
Han Wang ◽  
Dechao Meng ◽  
Guannan Qian ◽  
...  
Keyword(s):  
Crystal Growth ◽  
High Temperature ◽  
Surface Energy ◽  
Molten Salts ◽  
Rational Approach ◽  
Temperature Synthesis ◽  
Crystalline Materials ◽  
Size Dependent ◽  
High Temperature Synthesis ◽  
Energy Tuning

Crystalline materials are routinely produced via high-temperature synthesis and show size-dependent properties; however, a rational approach to regulating their crystal growth has not been established. Here we show that dopants...

scholarly journals Electron liquid state in the symmetric Anderson lattice

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Igor N. Karnaukhov
Keyword(s):  
Low Temperatures ◽  
Arbitrary Dimension ◽  
Mean Field ◽  
Coulomb Repulsion ◽  
Anomalous Behavior ◽  
Effective Field ◽  
Kondo Lattice ◽  
Field Approach ◽  
Cubic Lattices ◽  
Half Filling

AbstractUsing mean field approach, we provide analytical and numerical solution of the symmetric Anderson lattice for arbitrary dimension at half filling. The symmetric Anderson lattice is equivalent to the Kondo lattice, which makes it possible to study the behavior of an electron liquid in the Kondo lattice. We have shown that, due to hybridization (through an effective field due to localized electrons) of electrons with different spins and momenta $$\mathbf{k} $$ k and $$\mathbf{k} +\overrightarrow{\pi }$$ k + π → , the gap in the electron spectrum opens at half filling. Such hybridization breaks the conservation of the total magnetic momentum of electrons, the spontaneous symmetry is broken. The state of electron liquid is characterized by a large Fermi surface. A gap in the spectrum is calculated depending on the magnitude of the on-site Coulomb repulsion and value of s–d hybridization for the chain, as well as for square and cubic lattices. Anomalous behavior of the heat capacity at low temperatures in the gapped state, which is realized in the symmetric Anderson lattice, was also found.

scholarly journals Cooper Pair-Like Systems at High Temperature and their Role on Fluctuations Near the Critical Temperature

1998 ◽  
Vol 12 (29n31) ◽  
pp. 3216-3219 ◽  
Author(s):  
M. Ausloos ◽  
S. Dorbolo
Keyword(s):  
Phase Transition ◽  
Electrical Resistivity ◽  
High Temperature ◽  
Critical Temperature ◽  
Oxygen Diffusion ◽  
Cooper Pair ◽  
Anomalous Behavior ◽  
Anomalous Effect ◽  
Linear Temperature ◽  
Ybco Sample

A logarithmic behavior is hidden in the linear temperature regime of the electrical resistivity R(T) of some YBCO sample below 2T c where "pairs" break apart, fluctuations occur and "a gap is opening". An anomalous effect also occurs near 200 K in the normal state Hall coefficient. In a simulation of oxygen diffusion in planar 123 YBCO, an anomalous behavior is found in the oxygen-vacancy motion near such a temperature. We claim that the behavior of the specific heat above and near the critical temperature should be reexamined in order to show the influence and implications of fluctuations and dimensionality on the nature of the phase transition and on the true onset temperature.

Crystal Growth and High Temperature Piezoelectricity of La3Ta0.5Ga5.5 ? xAlxO14 Crystals

2004 ◽  
Vol 13 (1-3) ◽  
pp. 471-478 ◽  
Author(s):  
Il Hyoung Jung ◽  
Tsuguo Fukuda ◽  
Keun Ho Auh
Keyword(s):  
Crystal Growth ◽  
High Temperature

Potential of a Novel Thermotolerant Lipase Bacillus stearothermophilus nr22 (Lip.nr-22) as Additive in High Temperature Operated-Neutral pH Liquid Detergent

2017 ◽  
Vol 735 ◽  
pp. 136-142 ◽  
Author(s):  
Nik Raikhan Nik Him ◽  
Nurul Shafika Azmi
Keyword(s):  
High Temperature ◽  
Bacillus Stearothermophilus ◽  
Laundry Detergent ◽  
Detergent Formulation ◽  
Time Interval ◽  
Oil Removal ◽  
Optimum Conditions ◽  
Detergent Concentration ◽  
Neutral Ph ◽  
Commercial Detergents

Enzyme-added detergent must have the capability to operate at high temperature to support the enzyme proteins to clean soiled-fabrics at optimum conditions. Lipase from Bacillus stearothermophilus nr22 (Lip.nr-22) has improved the oil removal from soiled-cotton fabric by 38.8-51.4% in 4 types of local commercial detergents. The later was the oil removal from an unrevealed detergent. The optimum conditions were 108U/ml Lip.nr-22 in 0.1M, pH 7.0, washing temperature and washing time interval as 80°C and 40 min, respectively; shaking wash at 300 rpm and percentage of detergent concentration as 0.5. Lip.nr-22 is a very potential enzyme in high temperature-neutral pH operated laundry detergent formulations. It has exhibited a very excellent thermostability at 80°C, was very stable with surfactants, commercial detergents as well as with oxidizing agents (H2O2, NaBO3H2O and NaClO). Lip.nr-22 as additive in detergent formulation is a promise for better detergent formulation.

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