scholarly journals Спонтанные переходы в состояние высокой проводимости в композитных пленках поливинилхлорида

2019 ◽  
Vol 89 (12) ◽  
pp. 1933
Author(s):  
Т.В. Власова ◽  
С.И. Расмагин
Keyword(s):  
Applied Voltage ◽  
Experimental Studies ◽  
Anomalous Behavior ◽  
High Conductivity ◽  
Qualitative Model ◽  
Molecular Fragments ◽  
Variable Concentration ◽  
Living State ◽  
Conductivity Anomalies

The results of experimental studies of conductivity anomalies in film samples of specially synthesized copolymer are analyzed, in which in PVC macromolecules the polyacetylene molecular fragments are embedded with a variable concentration. It has been experimentally established that spontaneous and stimulated conduction jumps occur in such samples by 13 orders of magnitude, and the life of each of these states can be very large from a few minutes to a day. In paper we propose a qualitative model describing the anomalous behavior of the conductivity of the PVC composite, comprising the mechanisms of stabilization of high conductivity state, the conditions of development of instability in the transitions between the states, as well as the reasons for long living state of high conductivity even when the applied voltage is switched off. Simple numerical estimates confirming the reality of the proposed mechanisms are also considered.

scholarly journals Effect of Temperature, Pressure, and Chemical Composition on the Electrical Conductivity of Schist: Implications for Electrical Structures under the Tibetan Plateau

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 961 ◽  
Author(s):  
Wenqing Sun ◽  
Lidong Dai ◽  
Heping Li ◽  
Haiying Hu ◽  
Changcai Liu ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
High Pressures ◽  
High Conductivity ◽  
Effect Of Temperature ◽  
The Tibetan Plateau ◽  
Temperature Range ◽  
Electrical Conductivities ◽  
Conductivity Anomalies ◽  
Lower Temperature Range ◽  
Lower Temperature

The experimental study on the electrical conductivities of schists with various contents of alkali ions (CA = K2O + Na2O = 3.94, 5.17, and 5.78 wt.%) were performed at high temperatures (623–1073 K) and high pressures (0.5–2.5 GPa). Experimental results indicated that the conductivities of schist markedly increased with the rise of temperature. Pressure influence on the conductivities of schist was extremely weak at the entire range of experimental temperatures. Alkali ion content has a significant influence on the conductivities of the schist samples in a lower temperature range (623–773 K), and the influence gradually decreases with increasing temperature in a higher temperature range (823–1073 K). In addition, the activation enthalpies for the conductivities of three schist samples were fitted as being 44.16–61.44 kJ/mol. Based on the activation enthalpies and previous studies, impurity alkaline ions (K+ and Na+) were proposed as the charge carriers of schist. Furthermore, electrical conductivities of schist (10−3.5–10−1.5 S/m) were lower than those of high-conductivity layers under the Tibetan Plateau (10−1–100 S/m). It was implied that the presence of schist cannot cause the high-conductivity anomalies in the middle to lower crust beneath the Tibetan Plateau.

The Influence of Ni(II) and Co(II) Adsorptions in the Anomalous Behavior of Co-Ni Alloys: Density Functional Theory and Experimental Studies

2017 ◽  
Vol 2 (5) ◽  
pp. 1826-1834 ◽  
Author(s):  
Jorge Vazquez-Arenas ◽  
Guadalupe Ramos-Sanchez ◽  
Rene H. Lara ◽  
Issis Romero-Ibarra ◽  
M. Eng. Francisco Almazan ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Experimental Studies ◽  
Anomalous Behavior ◽  
Functional Theory ◽  
Ni Alloys

scholarly journals Магнитоструктурные особенности фазовых переходов в системе Mn-=SUB=-1-x-=/SUB=-Co-=SUB=-x-=/SUB=-NiGe Часть 1. Экспериментальные результаты

2021 ◽  
Vol 63 (12) ◽  
pp. 2073
Author(s):  
В.И. Митюк ◽  
Г.С. Римский ◽  
К.И. Янушкевич ◽  
В.В. Коледов ◽  
А.В. Маширов ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Magnetic Phase ◽  
Experimental Studies ◽  
Anomalous Behavior ◽  
Magnetic Phase Transitions ◽  
Strong Magnetic Fields ◽  
Weak Magnetic Fields ◽  
Wide Range ◽  
Co Concentrations

Experimental studies of the magnetic and structural properties of solid solutions of the Mn1-xCoxNiGe system in a wide range of Co concentrations (0.05≤ x≤ 0.8), temperatures (5 K≤ x≤600 K) and magnetic fields (0.016 T≤ x≤ 13.5 T) have revealed a number of nontrivial magnetic and magnetocaloric features of this system. The latter include: 1) a change in the nature of magnetic phase transitions from magnetostructural transitions of the 1st order paramagnetism-antiferromagnetism (0.05≤ x≤ 0.15) to isostructural transitions of the 2nd order paramagnetism-ferromagnetism (0.15≤ x≤0.8) with a change in the concentration of Co ; 2) anomalous behavior of low-temperature regions of magnetization in weak magnetic fields; 3) a change in the saturation magnetization and the appearance of irreversible magnetic field-induced transitions at helium temperatures in strong magnetic fields.

scholarly journals Experimental Studies on Fretting Wear Behavior of PVDF Piezoelectric Thin Films

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 734
Author(s):  
Yuanjie Shu ◽  
Liaoliang Ke ◽  
Jie Su ◽  
Fei Shen
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Applied Voltage ◽  
Polyvinylidene Fluoride ◽  
Normal Force ◽  
Wear Behavior ◽  
Experimental Studies ◽  
Displacement Amplitude ◽  
Fretting Wear ◽  
Wear Volume

This paper discusses an in-depth experimental study on the fretting wear behavior of PVDF (polyvinylidene fluoride) piezoelectric thin film against a Si3N4 ceramic sphere under air conditions. A fretting wear device with a ball-on-plate contact configuration was applied. The changes of displacement amplitude, normal force, and applied voltage were taken into account. The friction logs were used to determine the contact state of the PVDF thin film during the fretting test. The 3D topography instrument and scanning electron microscope (SEM) were used to measure the details of the surface morphology and wear volume. The test results of PVDF thin films under different normal force, displacement amplitude, and applied voltage are summarized through the collection and analysis of experimental data. It is shown that the creep and plastic deformation lead to obvious winkles at the contact surface, which may decrease the specific wear rate of PVDF thin films.

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