scholarly journals Experimental studies of the temperature dependence of Raman frequencies for Al2O3

2016 ◽  
Vol 77 ◽  
pp. 94-98
Author(s):  
Yurii Kryvenchuk ◽  
◽  
Ihor Mykytyn ◽  
Oleh Seheda ◽  
◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Experimental Studies

scholarly journals Hydrogen tunnelling in enzyme-catalysed H-transfer reactions: flavoprotein and quinoprotein systems

2006 ◽  
Vol 361 (1472) ◽  
pp. 1375-1386 ◽  
Author(s):  
Michael J Sutcliffe ◽  
Laura Masgrau ◽  
Anna Roujeinikova ◽  
Linus O Johannissen ◽  
Parvinder Hothi ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Variable Temperature ◽  
Isotope Effects ◽  
Experimental Studies ◽  
Zero Point ◽  
Reaction Rates ◽  
State Theory ◽  
Strong Temperature Dependence ◽  
Methylamine Dehydrogenase ◽  
Point Energy

It is now widely accepted that enzyme-catalysed C–H bond breakage occurs by quantum mechanical tunnelling. This paradigm shift in the conceptual framework for these reactions away from semi-classical transition state theory (TST, i.e. including zero-point energy, but with no tunnelling correction) has been driven over the recent years by experimental studies of the temperature dependence of kinetic isotope effects (KIEs) for these reactions in a range of enzymes, including the tryptophan tryptophylquinone-dependent enzymes such as methylamine dehydrogenase and aromatic amine dehydrogenase, and the flavoenzymes such as morphinone reductase and pentaerythritol tetranitrate reductase, which produced observations that are also inconsistent with the simple Bell-correction model of tunnelling. However, these data—especially, the strong temperature dependence of reaction rates and the variable temperature dependence of KIEs—are consistent with other tunnelling models (termed full tunnelling models), in which protein and/or substrate fluctuations generate a configuration compatible with tunnelling. These models accommodate substrate/protein (environment) fluctuations required to attain a configuration with degenerate nuclear quantum states and, when necessary, motion required to increase the probability of tunnelling in these states. Furthermore, tunnelling mechanisms in enzymes are supported by atomistic computational studies performed within the framework of modern TST, which incorporates quantum nuclear effects.

scholarly journals Thin Al 1− x Ga x As 0.56 Sb 0.44 diodes with extremely weak temperature dependence of avalanche breakdown

2017 ◽  
Vol 4 (5) ◽  
pp. 170071 ◽  
Author(s):  
Xinxin Zhou ◽  
Chee Hing Tan ◽  
Shiyong Zhang ◽  
Manuel Moreno ◽  
Shiyu Xie ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Breakdown Voltage ◽  
Experimental Studies ◽  
Temperature Stability ◽  
Operating Conditions ◽  
Avalanche Breakdown ◽  
Avalanche Gain ◽  
Weak Temperature Dependence ◽  
Inp Substrates ◽  
Tunnelling Current

When using avalanche photodiodes (APDs) in applications, temperature dependence of avalanche breakdown voltage is one of the performance parameters to be considered. Hence, novel materials developed for APDs require dedicated experimental studies. We have carried out such a study on thin Al 1– x Ga x As 0.56 Sb 0.44 p–i–n diode wafers (Ga composition from 0 to 0.15), plus measurements of avalanche gain and dark current. Based on data obtained from 77 to 297 K, the alloys Al 1− x Ga x As 0.56 Sb 0.44 exhibited weak temperature dependence of avalanche gain and breakdown voltage, with temperature coefficient approximately 0.86–1.08 mV K −1 , among the lowest values reported for a number of semiconductor materials. Considering no significant tunnelling current was observed at room temperature at typical operating conditions, the alloys Al 1− x Ga x As 0.56 Sb 0.44 (Ga from 0 to 0.15) are suitable for InP substrates-based APDs that require excellent temperature stability without high tunnelling current.

Experimental Studies of Temperature Dependence of Transfer Function of Molecular Electronic Transducers at High Frequencies

2016 ◽  
Vol 16 (22) ◽  
pp. 7864-7869 ◽  
Author(s):  
Dmitry L. Zaitsev ◽  
Pavel V. Dudkin ◽  
Tatiana V. Krishtop ◽  
Alexander V. Neeshpapa ◽  
Vladimir G. Popov ◽  
...  
Keyword(s):  
Transfer Function ◽  
Temperature Dependence ◽  
Experimental Studies ◽  
Molecular Electronic ◽  
High Frequencies

CVM Simulation of the Resistivity in L10 and L12 Co-Pt Intermetallic Compounds

1990 ◽  
Vol 213 ◽  
Author(s):  
J.M. Sanchez ◽  
M.C. Cadeville ◽  
V. Pierron-Bohnes
Keyword(s):  
Phase Diagram ◽  
Statistical Model ◽  
Temperature Dependence ◽  
Experimental Analysis ◽  
Magnetic Order ◽  
Experimental Studies ◽  
Spin Model ◽  
Spin Disorder ◽  
Magnetic Disorder ◽  
Theory And Experiment

ABSTRACTThe contributions of the atomic and spin disorder to the resistivity of two intermetallic Co1−x Ptx (x=0.5 and 0.7) compounds have been previously determined from experimental studies and separated from the phonon contribution. Now, the atomic and magnetic contributions and their variation with temperature through the Curie and order-disorder transitions are analyzed using a statistical model. The components of the resistivity are described as sums of resistivities of individual tetrahedral clusters. The cluster probabilities are calculated in a magnetic (up and down spin model) CVM approximation, the parameters of which are those that reproduce the experimental Co-Pt phase diagram. The contribution of chemically (magnetically) ordered clusters to the resistivity due to the chemical (magnetic) disorder are taken equal to zero. It is the temperature dependence of all other cluster probabilities which determine the resistivity behavior. Although there are severe approximations in both the experimental analysis and the statistical model, the agreement between theory and experiment is very satisfactory, underscoring the strong interplay between chemical and magnetic order in such ferromagnetic compounds.

Temperature and Frequency Dependent Characteristics of Amorphous Silicon thin film Transistors

1995 ◽  
Vol 377 ◽  
Author(s):  
H. C. Slade ◽  
M. S. Shur ◽  
M. Hack
Keyword(s):  
Thin Film ◽  
Temperature Dependence ◽  
Amorphous Silicon ◽  
Thin Film Transistors ◽  
Field Effect ◽  
Experimental Studies ◽  
Localized States ◽  
Field Effect Mobility ◽  
Silicon Thin Film ◽  
Capacitance Voltage

ABSTRACTOn the basis of our experimental studies of the temperature dependence of amorphous silicon thin film transistor current-voltage and capacitance-voltage characteristics, we have developed an analytical device model suitable for implementation in circuit simulators. This model describes the above-threshold (on) current and the subthreshold (off) current [1]. In addition, the model is able to incorporate changes in the distribution of localized states which arise from thermal and/or bias stress. In this paper, we identify the temperature-dependent parameters, which describe the temperature dependence of both the on and off currents, and we model the leakage current at large negative gate biases. The modeling results are in good agreement with our experimental data. We also discuss capacitance-voltage characteristics of amorphous silicon thin film transistors for varying gate lengths, temperatures, and frequencies. The measured capacitance-voltage characteristics show strong frequency dispersion, which is related to the trap-limited transport of carriers in the channel. The characteristic time constant, which determines when the channel capacitance becomes dependent on frequency, is on the order of the transit time calculated with the field-effect mobility and the electric field. The field-effect mobility takes into account carrier trapping by the localized states and is a function of gate voltage and temperature.

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