Are the low temperature-low frequency and high temperature-high frequency ac conductivity of glasses the same phenomenon?

1996 ◽  
Vol 203 ◽  
pp. 293-299 ◽  
Author(s):  
C.H. Hsieh ◽  
H. Jain
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
High Frequency ◽  
Ac Conductivity ◽  
Low Frequency ◽  
High Frequency Ac

Application of Damage Concepts to Predict Creep-Fatigue Failures

1979 ◽  
Vol 101 (3) ◽  
pp. 284-292 ◽  
Author(s):  
J. Lemaitre ◽  
A. Plumtree
Keyword(s):  
High Temperature ◽  
High Frequency ◽  
Low Frequency ◽  
Strain Range ◽  
Ofhc Copper ◽  
Unified Approach ◽  
Alloy 800 ◽  
Sequential Tests ◽  
Creep Fatigue ◽  
Fatigue Failures

The damage concept has been developed in terms of strain range in order to give a unified approach to high temperature failure. Interactive tests have been carried out on OFHC copper at 540°C and Sanicro 31 (Alloy 800) at 600°C. For the former, combined strain controlled low frequency and high frequency tests were undertaken whereas the latter metal was subjected to sequential tests involving monotonic creep and high frequency cycling. The damage concept based on non-linear accumulation predicted lives which were in agreement with those observed experimentally for the two materials.

Cuprate High Temperature Superconductors and the Vision for Room Temperature Superconductivity

SPIN ◽  
2017 ◽  
Vol 07 (02) ◽  
pp. 1750006 ◽  
Author(s):  
Dennis M. Newns ◽  
Glenn J. Martyna ◽  
Chang C. Tsuei
Keyword(s):  
High Temperature ◽  
High Frequency ◽  
Room Temperature ◽  
Phonon Frequency ◽  
High Temperature Superconductors ◽  
Low Frequency ◽  
Unconventional Superconductivity ◽  
Superconducting Transition ◽  
Strongly Coupled ◽  
Room Temperature Superconductivity

Superconducting transition temperatures of 164 K in cuprate high temperature superconductors (HTS) and recently 200 K in H3S under high pressure encourage us to believe that room temperature superconductivity (RTS) might be possible. In considering paths to RTS, we contrast conventional (BCS) SC, such as probably manifested by H3S, with the unconventional superconductivity (SC) in the cuprate HTS family. Turning to SC models, we show that in the presence of one or more van Hove singularities (vHs) near the Fermi level, SC mediated by classical phonons ([Formula: see text]phonon frequency) can occur. The phonon frequency in the standard [Formula: see text] formula is replaced by an electronic cutoff, enabling a much higher [Formula: see text] independent of phonon frequency. The resulting [Formula: see text] and isotope shift plot versus doping strongly resembles that seen experimentally in HTS. A more detailed theory of HTS, which involves mediation by classical phonons, satisfactorily reproduces the chief anomalous features characteristic of these materials. We propose that, while a path to RTS through an H3S-like scenario via strongly-coupled ultra-high frequency phonons is attractive, features perhaps unavailable at ordinary pressures, a route involving SC mediated by classical phonons which can be low frequency may be found.

Research and Analysis of Clinical Application of Intelligent Low Temperature Plasma System

2014 ◽  
Vol 602-605 ◽  
pp. 3052-3055
Author(s):  
Zhi Bin Liu ◽  
Xiao Bo Mao
Keyword(s):  
Low Temperature ◽  
High Frequency ◽  
Operating Time ◽  
Low Temperature Plasma ◽  
Surgical Operation ◽  
Plasma System ◽  
Plasma Therapy ◽  
Temperature Plasma ◽  
Ac Electric Field ◽  
High Frequency Ac

According to the requirements of general surgical operation, we designed the plasma therapy system which took the microprocessor as the control core based on medical low temperature plasma technology. Making use of High-frequency AC electric field exciting ions in the electrolyte can generate low temperature plasma. Conclusion: the low-temperature plasma therapy system can significantly reduce blood loss and length of incision, shorten operating time, and postoperative complications in general surgical operation.

The Mo2FeB2- and Mn2AlB2-Type Modifications of RE2Ni2Cd (Re = La, Pr, Nd, Sm, Tb, Dy)

2005 ◽  
Vol 60 (3) ◽  
pp. 271-276 ◽  
Author(s):  
Thomas Fickenscher ◽  
Ute C. Rodewald ◽  
Dirk Niepmann ◽  
Ratikanta Mishra ◽  
Marcus Eschen ◽  
...  
Keyword(s):  
Rare Earth ◽  
High Temperature ◽  
Low Temperature ◽  
Rare Earth Metal ◽  
High Frequency ◽  
Earth Metal ◽  
Two Dimensional ◽  
Space Group ◽  
X Ray ◽  
Sample Chamber

The rare earth metal (RE)-nickel-cadmium intermetallics RE2Ni2Cd (RE = La, Pr, Nd, Sm, Tb, Dy) were prepared from the elements in sealed niobium or tantalum tubes in a water-cooled sample chamber of a high-frequency furnace. They crystallize with a tetragonal Mo2FeB2 type low-temperature modification, space group P4/mbm, and an orthorhombic Mn2AlB2 type hightemperature modification, space group Cmmm. The cadmium compounds were characterized through their X-ray powder patterns. Five structures of the low-temperature modifications were refined from X-ray single crystal diffractometer data: α = 763.76(9), c = 387.26(8) pm, wR2 = 0.046, 205 F2 for La2Ni1.67(1)Cd; α = 752.93(7), c = 380.95(6) pm, wR2 = 0.061, 260 F2 for Pr2Ni2Cd; α = 750.88(9), c = 378.33(7) pm, wR2 = 0.051, 195 F2 for Nd2Ni2Cd; α = 743.6(1), c = 374.0(1) pm, wR2 = 0.036, 386 F2 for Sm2Ni1.93(1)Cd; α = 734.9(1), c = 366.1(2) pm, wR2 = 0.030, 252 F2 for Dy2Ni1.94(1)Cd, with 13(12) variables per refinement. The 4g nickel site is only fully occupied in the neodymium and the praseodymium compound. Both modifications can be considered as intergrowths of distorted AlB2 and CsCl related slabs. In both modification the nickel and cadmium atoms build up two-dimensional [Ni2Cd] networks. In the low-temperature modifications the nickel atoms form pairs, while nickel zig-zag chains occur in the high-temperature modifications. These nickel fragments are condensed via the cadmium atoms. The crystal chemistry and the chemical bonding in these intermetallics is discussed

Proportional Resonant Controlled Dual Active Bridge DC to AC Converter System with Enhanced Response

2018 ◽  
Vol 9 (1) ◽  
pp. 316
Author(s):  
R. Sowmya ◽  
S. Rama Reddy
Keyword(s):  
High Frequency ◽  
Closed Loop ◽  
Low Frequency ◽  
High Gain ◽  
Open Loop ◽  
Controlled System ◽  
Dual Active Bridge ◽  
Resonant Controller ◽  
Time Domain Response ◽  
High Frequency Ac

<p>This paper deals with comparison of responses of PI and Proportional Resonant controlled DC to AC Converter systems. The objective of this work is to regulate the output of Dual Active Bridge DC to DC converter (DABDAC). The input DC is converted into high frequency AC using Half bridge inverter. It is stepped up by using step up transformer and then it is rectified. The DC is converted into Low frequency AC using a Half bridge inverter. The open loop DABDAC system, closed loop PI based DABDAC system an Proportional Resonant Controller (PRC)based DABDAC system are designed, modeled and simulated using MATLAB Simulink. The results of PR controlled system are compared with those of PI controlled system. The results indicate that the proposed PRC-DABDAC has better time domain response than PI controlled DABDAC system. The proposed DABDAC system has advantages like high gain and steady state error in output voltage. </p>

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