scholarly journals Nonlinear effect of carrier drift on the performance of an n-type ZnO nanowire nanogenerator by coupling piezoelectric effect and semiconduction

2018 ◽  
Vol 9 ◽  
pp. 1917-1925 ◽  
Author(s):  
Yuxing Liang ◽  
Shuaiqi Fan ◽  
Xuedong Chen ◽  
Yuantai Hu
Keyword(s):  
Carrier Concentration ◽  
Cross Section ◽  
Electric Fields ◽  
Electric Charge ◽  
Opposite Effect ◽  
Piezoelectric Effect ◽  
Axial Direction ◽  
Zno Nanowire ◽  
Electrode Size ◽  
Piezoelectric Semiconductors

In piezoelectric semiconductors, electric fields drive carriers into motion/redistribution, and in turn the carrier motion/redistribution has an opposite effect on the electric field itself. Thus, carrier drift in a piezoelectric semiconducting structure is essentially nonlinear unless the induced fluctuation of carrier concentration is very small. In this paper, the nonlinear governing equation of carrier concentration was established by coupling both piezoelectric effect and semiconduction. A nonlinear carrier-drift effect on the performance of a ZnO nanogenerator was investigated in detail and it was elucidated that carrier motion/redistribution occurs in the ZnO nanowire (ZNW) cross section while there is no carrier motion in the axial direction. At the same time, we noted that the amplitude of boundary electric charge grows with increasing deformation, but the peaks of boundary electric charge do not appear at the cross-section endpoints. Thus, in order to effectively improve the performance of the ZNW nanogenerator, the effect of electrode configuration on the piezoelectric potential difference and output power was analyzed in detail. The electrode size for the optimal performance of a ZnO nanowire generator was proposed. This analysis that couples electromechanical fields and carrier concentration as a whole has some referential significance to piezotronics.

Piezoelectric Potential Distribution in a Bent ZnO Nanorod Cantilever

2011 ◽  
Vol 694 ◽  
pp. 23-27
Author(s):  
Zheng Zheng Shao ◽  
Xue Ao Zhang ◽  
Fei Wang ◽  
Guang Wang ◽  
Hong Hui Jia ◽  
...  
Keyword(s):  
Carrier Concentration ◽  
Cross Section ◽  
Electric Potential ◽  
Potential Distribution ◽  
Piezoelectric Effect ◽  
Longitudinal Direction ◽  
Lateral Force ◽  
Negative Potential ◽  
Zno Nanorod ◽  
Piezoelectric Potential

The piezoelectric potential generated in a bent ZnO nanorod cantilever is analyzed by means of the first piezoelectric effect approximation. The results show that the piezoelectric potential in the nanorod is proportional to lateral force but is independent along the longitudinal direction. And the electric potential in the tensile area and that of compressive area are antisymmetric in cross section of the nanorod, which makes the nanorod become a "parallel plated capacitor" for piezoelectric nanodevices, such as nanogenerator. The investigation of the carriers influence on the piezoelectric potential in a bent ZnO nanorod reveals that the positive piezoelectric potential in stretched side of the bent nanorod is significantly screened by the carriers and the negative potential in compressed side is well preserved when considering a moderate carrier concentration of

FERROELECTRICS IN ACOUSTOELECTRONICS

Akustika ◽  
2021 ◽  
pp. 217
Author(s):  
Tamara Patrusheva ◽  
Sergey Petrov ◽  
Ludmila Drozdova ◽  
Aleksandr Shashurin
Keyword(s):  
Dielectric Constant ◽  
Electric Fields ◽  
Piezoelectric Effect ◽  
Complex Oxide ◽  
Ferroelectric Materials ◽  
Oxide Materials ◽  
Ferroelectric Films ◽  
Synthesis Time ◽  
Resonance Effects ◽  
Materials Used

Аcoustoelectronics is one of the areas of acoustics, associated with the use of mechanical resonance effects and the piezoelectric effect, as well as the effect based on the interaction of electric fields with waves of acoustic stresses in a piezoelectric material. The main materials used in acoustoelectronics are ferroelectrics, which are mainly complex oxide materials. This article discusses the possibility of increasing the purity and homogeneity of ferroelectric materials, as well as softening the regimes of their synthesis using the solution extraction-pyrolytic method. It is shown that the synthesis temperatures of BaTiO3, SrTiO3, and Pb(Zr)TiO3 ferroelectric films are reduced to 550-600°C, and the synthesis time is down to 5-10 minutes. The dielectric constant and Curie temperature values correspond to the maximum characteristics for these materials. Thus, using the extraction-pyrolytic method we obtained suitable for use in acoustoelectronic technology ferroelectric films.

Enhanced selectivity of methane production for photocatalytic reduction by the piezoelectric effect

2017 ◽  
Vol 53 (70) ◽  
pp. 9765-9768 ◽  
Author(s):  
Kaiqiang Wang ◽  
Zhibin Fang ◽  
Xueyan Huang ◽  
Wenhui Feng ◽  
Yaozhu Wang ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Ultrasonic Irradiation ◽  
Methane Production ◽  
Piezoelectric Effect ◽  
Photocatalytic Reduction ◽  
Piezoelectric Potential ◽  
Piezoelectric Semiconductors ◽  
Enhanced Selectivity

Under simultaneous full arc light and ultrasonic irradiation, photo-generated electrons are brought together by piezoelectric potential, and thus dense electrons induce the reduction of carbon dioxide on the surface of piezoelectric semiconductors, resulting in an improved selectivity of methane production to a greater degree.

scholarly journals CHARGE INFLUENCE ON MINI BLACK HOLE'S CROSS SECTION

2010 ◽  
Vol 19 (08n10) ◽  
pp. 1265-1269
Author(s):  
R. S. CARAÇA ◽  
M. MALHEIRO
Keyword(s):  
Cross Section ◽  
Electric Charge ◽  
Mass Ratio ◽  
Horizon Radius ◽  
Maximum Charge ◽  
Light Ions ◽  
Ratio Condition ◽  
The Cross ◽  
Mini Black Holes ◽  
Section Production

In this work we study the electric charge effect on the cross section production of charged mini black holes (MBH) in accelerators. We analyze the charged MBH solution using the fat brane approximation in the context of the ADD model. The maximum charge–mass ratio condition for the existence of a horizon radius is discussed. We show that the electric charge causes a decrease in this radius and, consequently, in the cross section. This reduction is negligible for protons and light-ions but can be important for heavy-ions.

A Variational Method for Fully Developed Laminar Heat Transfer in Ducts

1959 ◽  
Vol 81 (2) ◽  
pp. 157-164 ◽  
Author(s):  
E. M. Sparrow ◽  
R. Siegel
Keyword(s):  
Heat Transfer ◽  
Laminar Flow ◽  
Variational Method ◽  
Cross Section ◽  
Cross Sections ◽  
Axial Direction ◽  
Circular Sector ◽  
Thermal Boundary Conditions ◽  
Temperature Distributions ◽  
Good Agreement

A variational method is presented for determining fully developed velocity and temperature distributions for laminar flow in noncircular ducts. The heat addition to the fluid is taken to be uniform in the axial direction, but a variety of thermal boundary conditions are considered around the periphery of the duct cross section. Several illustrative examples are given, and comparisons are made which show good agreement with available exact solutions. These examples include ducts of rectangular and circular-sector cross sections.

Analysis of Acoustic Propagation Characteristic of Near-Bit Drill Tools

2012 ◽  
Vol 524-527 ◽  
pp. 1335-1338
Author(s):  
Zhi Gang Li ◽  
Shi Tong Ge ◽  
Zhi Chuan Guan
Keyword(s):  
Acoustic Wave ◽  
Cross Section ◽  
Time Domain ◽  
Axial Direction ◽  
Propagation Characteristic ◽  
Pass Band ◽  
The Finite Element Method ◽  
Drilling Tools ◽  
The Time Domain ◽  
Drill Collar

In order to Make Use of Acoustic Wave to Transmit the Information from near- Bit End to a Remote Bit End, Using the Finite Element Method, Simulate and Analyze the Acoustic Wave Propagating Characters of Common near-bit Drill Tools: Ordinary Drill Collar, Spiral Drill Collar, Integral Straight Edge Stabilizer, Integral Spiral Stabilizer and Screw Drill. the Results Show that: because the Form and Size of Axial Cross Section Are in Basic Consistent, the Ordinary Drill Collar and Spiral Drill Collar Not only Have Better Characteristics in Time Domain, No Repeated Oscillation of Waveform Occurring, but Also Have Wider Bandwidth (up to 4KHz), and because of the Stabilizer Section, the Acoustic Impedance in the Axial Direction Discontinuities and the Time Domain Waveforms of other Three Kinds of Drilling Tools Appear that Not only Waveforms Have Shook Repeatedly, but Also the Width of the Pass Band Has Narrowed Significantly.

scholarly journals The passage of a perfect fluid through a critical cross-section or ‘throat’

1949 ◽  
Vol 197 (1051) ◽  
pp. 545-555 ◽  
Keyword(s):  
Cross Section ◽  
Liquid Flow ◽  
Axial Direction ◽  
Critical Cross Section ◽  
Local Velocity ◽  
Velocity Of Sound ◽  
Long Wave ◽  
Venturi Flume ◽  
External Forces ◽  
Horizontal Bottom

A review is given of the methods previously adopted of calculating the discharge of a gas through a convergent-divergent nozzle and of a liquid over a broad-crested weir, through a Venturi flume with a horizontal bottom, and in a swirling state through a vertical nozzle. The assumption is made throughout that conditions are uniform over each cross-section of the constriction. Hugoniot’s method is shown to be preferable, and it is used to examine the discharge of a liquid through a Venturi flume of any shape and of a swirling gas through a nozzle. It is pointed out that, if an external force is operating in the axial direction, the local velocity of sound or of a long wave, as the case may be, is not attained by the fluid at the exact geometrical throat of the constriction. For the general case of liquid flow, whether swirling or not, the axial velocity of streaming in the absence of external forces is shown to be equal at the throat to the velocity of a long wave.

Electron energy distributions in uniform electric fields and the Townsend ionization coefficient

1958 ◽  
Vol 244 (1237) ◽  
pp. 166-185 ◽  
Keyword(s):  
Differential Equation ◽  
Cross Section ◽  
Electric Fields ◽  
Cross Sections ◽  
Collision Cross Section ◽  
Present Theory ◽  
Uniform Electric Field ◽  
Ionization Coefficient ◽  
Special Cases ◽  
Wide Range

The second-order differential equation which expresses the equilibrium condition of an electron swarm in a uniform electric field in a gas, the electrons suffering both elastic and inelastic collisions with the gas molecules, is solved by the Jeffreys or W.K.B. method of approximation. The distribution function F(ε) of electrons of energy ε is obtained immediately in a general form involving the elastic and inelastic collision cross-sections and without any restriction on the range of E/p (electric strength/gas pressure) save that introduced in the original differential equation. In almost all applications the approximation is likely to be of high accuracy, and easy to use. Several of the earlier derivations of F(ε) are obtained as special cases. Using the function F(ε) an attempt is made to relate the Townsend ionization coefficient a to the properties of the gas in a more general manner than hitherto, using realistic functions for the collision cross-section. It is finally expressed by the equation α/ p = A exp ( — Bp/E ) in which A and B are functions involving the properties of the gas and the ratio E/p . The important coefficient B is directly related to the form and magnitude of the total inelastic cross-section below the ionization potential and can be evaluated for a particular gas once the cross-section is known experimentally. The present theory shows clearly the influence of E/p on both A and B, a matter which has not been satisfactorily discussed previously. The theory is illustrated by calculations of F (ε) and a/p for hydrogen over a range of E/p from 10 to 1000. The agreement between the calculated results and recent reliable observations of α/ p is surprisingly good considering the nature of the calculations and the wide range of E/p .

scholarly journals Ion energy increase in laser-generated plasma expanding through axial magnetic field trap

2007 ◽  
Vol 25 (3) ◽  
pp. 453-464 ◽  
Author(s):  
L. Torrisi ◽  
D. Margarone ◽  
S. Gammino ◽  
L. Andò
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Electric Fields ◽  
Axial Magnetic Field ◽  
Ion Beam ◽  
High Vacuum ◽  
Target Surface ◽  
Axial Direction ◽  
Ion Interactions ◽  
The Magnetic Field

Laser-generated plasma is obtained in high vacuum (10−7 mbar) by irradiation of metallic targets (Al, Cu, Ta) with laser beam with intensities of the order of 1010 W/cm2. An Nd:Yag laser operating at 1064 nm wavelength, 9 ns pulse width, and 500 mJ maximum pulse energy is used. Time of flight measurements of ion emission along the direction normal to the target surface were performed with an ion collector. Measurements with and without a 0.1 Tesla magnetic field, directed along the normal to the target surface, have been taken for different target-detector distances and for increasing laser pulse intensity. Results have demonstrated that the magnetic field configuration creates an electron trap in front of the target surface along the axial direction. Electric fields inside the trap induce ion acceleration; the presence of electron bundles not only focuses the ion beam but also increases its energy, mean charge state and current. The explanation of this phenomenon can be found in the electric field modification inside the non-equilibrium plasma because of an electron bunching that increases the number of electron-ion interactions. The magnetic field, in fact, modifies the electric field due to the charge separation between the clouds of fast electrons, many of which remain trapped in the magnetic hole, and slow ions, ejected from the ablated target; moreover it increases the number of electron-ion interactions producing higher charge states.

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