Influence of Multiple Piezoelectric Effects on Piezoelectric Coefficient of Piezoelectric Ceramics

2011 ◽  
Vol 101-102 ◽  
pp. 922-925 ◽  
Author(s):  
Zhong Hua Zhang ◽  
Guang Ming Cheng ◽  
Jun Wu Kan ◽  
Ping Zeng ◽  
Jian Ming Wen
Keyword(s):  
Boundary Condition ◽  
Theoretical Analysis ◽  
Experimental Validation ◽  
Piezoelectric Coefficient ◽  
Short Circuit ◽  
Piezoelectric Ceramics ◽  
Open Circuit ◽  
Experimental Results ◽  
Experimental Result ◽  
Piezoelectric Effects

In this paper, theoretical analysis is performed on the influence of multiple piezoelectric effects on piezoelectric coefficients. And a kind of classical piezoelectric ceramics was adopted to conduct the experimental validation. The experimental results of short-circuit boundary condition are obtained by the methods that a capacitor whose capacitance is much larger than that of the stack is parallel with PZT-5. Influence results are obtained through comparing them with open-circuit piezoelectric coefficient. Experimental result shows that multiple piezoelectric effects make piezoelectric coefficient of PZT-5 be altered by 18%.

Study on the Small Molecule Organic Solar Cells with Anode Buffer Layer

2012 ◽  
Vol 550-553 ◽  
pp. 476-479
Author(s):  
Ai Fen Wang
Keyword(s):  
Buffer Layer ◽  
Active Layer ◽  
Organic Solar Cells ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Photovoltaic Cell ◽  
Open Circuit ◽  
Experimental Result ◽  
Anode Buffer Layer ◽  
Buffer Material

The three photovoltaic cells with two different anode buffer layer on the basis of Pentacene/C60 as active layer was fabicated, the effect and mechanism of anode buffer layer on performance of organic photovoltaic cell are explored. The experimental result shows transition metal oxide inserted between organic active layer and ITO could increase short circuit current and open-circuit voltage,power conversion efficiency is increased to 107%,so it is effective anode buffer material.

scholarly journals RESEARCH ON SHORT-CIRCUIT IMPEDANCES OF NEW CONVERTER TRANSFORMER

2020 ◽  
Vol 38 (02) ◽  
Author(s):  
TRAN THANH NGOC
Keyword(s):  
Theoretical Analysis ◽  
Topological Structure ◽  
Short Circuit ◽  
Experimental Results ◽  
New Method ◽  
Mathematical Relationship ◽  
Hvdc System ◽  
Grid Side ◽  
Relationship Of ◽  
Circuit Impedance

The short-circuit impedance of converter transformers is one of the most important specifications in HVDC system. Compared with the traditional converter transformers, the new converter transformer has unique windings connection diagrams. Based on the topological structure of the new converter transformer, this paper proposes a new method to establish the mathematical relationship of short-circuit impedances and filters impedances under considering the valve side and grid side shortcircuit conditions. The analysis on short circuit at valve side and grid side shows that short-circuit impedances values are almost the same in both two conditions, so that the impedance of the new converter transformer is symmetrical. Finally, simulation and experimental results verify the correctness of the theoretical analysis.

An investigation of the tertiary coupling effect under the longitudinal mode of a piezoelectric crystal

2009 ◽  
Vol 223 (8) ◽  
pp. 1777-1785 ◽  
Author(s):  
Z H Zhang ◽  
B Y Sun ◽  
M Qian ◽  
J Zhang ◽  
Y H Shi ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Boundary Conditions ◽  
Piezoelectric Effect ◽  
Coupling Effect ◽  
Longitudinal Mode ◽  
Experimental Results ◽  
Sensors And Actuators ◽  
Piezoelectric Effects ◽  
Converse Piezoelectric Effect ◽  
The Relationship

In this article, multiple piezoelectric effects are investigated on the basis of the classical piezoelectric theory. The objective reality of multiple piezoelectric effects is elucidated from theoretical analysis first. Based on four kinds of piezoelectric equations, the relationship between the generation of multiple piezoelectric effects and boundary conditions is analysed, the process of their generation is elaborated, and the formulae of the tertiary piezoelectric effect are deduced. Then, the experimental results of the tertiary coupling effect are obtained under the longitudinal mode of a PZT-5 stack by the methods that are equivalent to changing boundary conditions. Experimental data show that the output of the tertiary direct and converse piezoelectric effect is also linear with the applied force and voltage, respectively. However, the output directions are opposite to that of the primary piezoelectric effect. The theoretical analysis is justified by experimental results and the experimental methods presented are proved to be scientific and feasible. Moreover, the influence of the tertiary piezoelectric effect on the piezoelectric coefficient and the performance of sensors and actuators is further analysed. The study of multiple piezoelectric effects provides a new method for the improvement of the performance of piezoelectric sensors and actuators.

scholarly journals Current-pumping performance of axial-symmetric superconducting dynamo designs

2021 ◽  
Author(s):  
◽  
Sin Hoi Phang
Keyword(s):  
Liquid Nitrogen ◽  
Output Voltage ◽  
Short Circuit ◽  
Local Heating ◽  
Open Circuit ◽  
Experimental Results ◽  
Operating Frequency ◽  
Design Parameters ◽  
Dynamic Resistance ◽  
Frequency Regime

<p>In this project, the current pumping performances of three high temperature superconducting (HTS) dynamos (mechanically-rotating flux pumps) were investigated. These flux pumps (FPs) were identified as the Gen 1, Gen 2 and Gen 4 FP respectively. They were modelled using simple DC equivalent circuits and their performances were defined by three output parameters: DC open-circuit voltage (Voc), dynamic resistance (Rd) and DC short-circuit current (Isc). The experimental results showed that these FPs produced non-zero DC output voltages across their stators and each supplied DC output currents into series connected superconducting circuits.  The Gen 1 FP was cooled with liquid nitrogen and operated at 77 K. The stators were made from 12-mm wide copper-coated yttrium barium copper oxide (YBCO) HTS conductors. The objective of the experiment was to investigate the effect of the rotor magnet size, geometry and orientation (with respect to the stators) on the FP performance. The design parameters, based on the width and the length of the magnet with respect to the stator, for optimal FP performance were determined.  The Gen 2 FP was also cooled with liquid nitrogen and operated at 77 K. The stators were made from 46-mm wide Ag-coated YBCO HTS conductors. The objective of the experiment was to investigate the effect of stator width on the FP performance at various magnet frequencies. This was done by slitting two of the stators to form parallel stators with equal width, but smaller than the original conductor width. The experimental results showed that the FP performance was highly dependent on the operating frequency. Three operating frequency regimes were observed: low, mid and high. At high frequency, the Voc decreased and the Rd increased signifcantly. This was attributed to the local heating effect in the stator due to the increase in the current density. As a result, the FP produced zero output current in this regime. The AC voltage waveforms measured across the stators in different frequency regimes were very different in shapes and amplitudes. Therefore, these waveforms can be used to identify the operating frequency regime of the FP. At some operating frequencies in the mid frequency regime, bi-stable operating modes were observed, each mode resulted in different output parameters.  The Gen 4 FP was constructed in this project. It was cooled via thermal conduction method using a cryorefrigerator system. It had an axial-symmetric stator design where the shape of the stator is cylindrical. The width of the stator was considerably larger compared with the Gen 1 and Gen 2 FPs. The experiment objective was to investigate whether this design would produce a DC current, and then characterise the FP performance at different operating temperatures. The experimental results showed that the time-averaged DC output voltage of the Gen 4 FP was much higher compared with the Gen 1 and Gen 2 FPs. The reason is that it produced a DC output voltage for almost the entire rotor cycle. The experimental results also indicated that the Gen 4 FP has the capability to produce output currents in the kA range.</p>

scholarly journals Current-pumping performance of axial-symmetric superconducting dynamo designs

2021 ◽  
Author(s):  
◽  
Sin Hoi Phang
Keyword(s):  
Liquid Nitrogen ◽  
Output Voltage ◽  
Short Circuit ◽  
Local Heating ◽  
Open Circuit ◽  
Experimental Results ◽  
Operating Frequency ◽  
Design Parameters ◽  
Dynamic Resistance ◽  
Frequency Regime

<p>In this project, the current pumping performances of three high temperature superconducting (HTS) dynamos (mechanically-rotating flux pumps) were investigated. These flux pumps (FPs) were identified as the Gen 1, Gen 2 and Gen 4 FP respectively. They were modelled using simple DC equivalent circuits and their performances were defined by three output parameters: DC open-circuit voltage (Voc), dynamic resistance (Rd) and DC short-circuit current (Isc). The experimental results showed that these FPs produced non-zero DC output voltages across their stators and each supplied DC output currents into series connected superconducting circuits.  The Gen 1 FP was cooled with liquid nitrogen and operated at 77 K. The stators were made from 12-mm wide copper-coated yttrium barium copper oxide (YBCO) HTS conductors. The objective of the experiment was to investigate the effect of the rotor magnet size, geometry and orientation (with respect to the stators) on the FP performance. The design parameters, based on the width and the length of the magnet with respect to the stator, for optimal FP performance were determined.  The Gen 2 FP was also cooled with liquid nitrogen and operated at 77 K. The stators were made from 46-mm wide Ag-coated YBCO HTS conductors. The objective of the experiment was to investigate the effect of stator width on the FP performance at various magnet frequencies. This was done by slitting two of the stators to form parallel stators with equal width, but smaller than the original conductor width. The experimental results showed that the FP performance was highly dependent on the operating frequency. Three operating frequency regimes were observed: low, mid and high. At high frequency, the Voc decreased and the Rd increased signifcantly. This was attributed to the local heating effect in the stator due to the increase in the current density. As a result, the FP produced zero output current in this regime. The AC voltage waveforms measured across the stators in different frequency regimes were very different in shapes and amplitudes. Therefore, these waveforms can be used to identify the operating frequency regime of the FP. At some operating frequencies in the mid frequency regime, bi-stable operating modes were observed, each mode resulted in different output parameters.  The Gen 4 FP was constructed in this project. It was cooled via thermal conduction method using a cryorefrigerator system. It had an axial-symmetric stator design where the shape of the stator is cylindrical. The width of the stator was considerably larger compared with the Gen 1 and Gen 2 FPs. The experiment objective was to investigate whether this design would produce a DC current, and then characterise the FP performance at different operating temperatures. The experimental results showed that the time-averaged DC output voltage of the Gen 4 FP was much higher compared with the Gen 1 and Gen 2 FPs. The reason is that it produced a DC output voltage for almost the entire rotor cycle. The experimental results also indicated that the Gen 4 FP has the capability to produce output currents in the kA range.</p>

scholarly journals Development of Method of Moment Based Programme to Analyze Cross Dipole Frequency Selective Surface and its Verification with Measured Results

2020 ◽  
Vol 9 (8) ◽  
pp. 1019-1023
Keyword(s):  
Theoretical Analysis ◽  
Satellite Communication ◽  
Test Bench ◽  
Frequency Selective Surface ◽  
Experimental Results ◽  
Experimental Result ◽  
Method Of Moment ◽  
Frequency Selective ◽  
Matlab Programming

Theoretical analysis of frequency selective surface comprising of cross dipole elements has been presented in this paper. Algorithm for theoretical analysis based on method of moment has been implemented by MATLAB programming. Theoretical, simulated and experimental results are compared. Simulated result is obtained by ANSOFT designer version 2.2 software. Experimental result is obtained by standard microwave test bench. Good parity in the results is observed. The presented FSS Structure has relevance in the field of mobile and satellite communication.

The Influence of Multiple Piezoelectric Effects on Elastic Coefficient of Piezoelectric Ceramics

2011 ◽  
Vol 305 ◽  
pp. 348-352 ◽  
Author(s):  
Zhong Hua Zhang ◽  
Guang Ming Cheng ◽  
Jun Wu Kan ◽  
Ping Zeng ◽  
Jian Ming Wen
Keyword(s):  
Performance Improvement ◽  
Experimental Validation ◽  
Piezoelectric Ceramics ◽  
Elastic Compliance ◽  
Theoretical Research ◽  
New Materials ◽  
Elastic Coefficient ◽  
Compliance Coefficient ◽  
Piezoelectric Effects ◽  
Compliance Coefficients

The development of new materials and the performance improvement of existing materials become an important subject from different aspects. In this paper, based on the theoretical research results of multiple piezoelectric effects, the influence of multiple piezoelectric effects on elastic coefficient of piezoelectric ceramics is studied. Theoretical analysis indicates that it is multiple piezoelectric effects that make piezoelectrics have two kinds of elastic and they result in the decrease of elastic compliance coefficients. Experimental validation is performed through PZT-5. Experimental results show that elastic compliance coefficient grows decreased by 0.912 times.

Lock-in Thermography-Based Local Efficiency Analysis of Solar Cells

2012 ◽  
Author(s):  
Otwin Breitenstein
Keyword(s):  
Solar Cells ◽  
Short Circuit ◽  
Efficiency Analysis ◽  
Open Circuit ◽  
Local Defect ◽  
Whole Cell ◽  
Local Efficiency ◽  
Cell Efficiency ◽  
Lock In ◽  
Efficiency Data

Abstract The electronic properties of solar cells, particularly multicrystalline silicon-based ones, are distributed spatially inhomogeneous, where regions of poor quality may degrade the performance of the whole cell. These inhomogeneities mostly affect the dark current-voltage (I-V) characteristic, which decisively affects the efficiency. Since the grid distributes the local voltage homogeneously across the cell and leads to lateral balancing currents, local light beam-induced current methods alone cannot be used to image local cell efficiency parameters. Lock-in thermography (LIT) is the method of choice for imaging inhomogeneities of the dark I-V characteristic. This contribution introduces a novel method for evaluating a number of LIT images taken at different applied biases. By pixel-wise fitting the data to a two diode model and taking into account local series resistance and short circuit current density data, realistically simulated images of the other cell efficiency parameters (open circuit voltage, fill factor, and efficiency) are obtained. Moreover, simulated local and global dark and illuminated I-V characteristics are obtained, also for various illumination intensities. These local efficiency data are expectation values, which would hold if a homogeneous solar cell had the properties of the selected region of the inhomogeneous cell. Alternatively, also local efficiency data holding for the cell working at its own maximum power point may be generated. The amount of degradation of different cell efficiency parameters in some local defect positions is an indication how dangerous these defects are for degrading this parameter of the whole cell. The method allows to virtually 'cut out' certain defects for checking their influence on the global characteristics. Thus, by applying this method, a detailed local efficiency analysis of locally inhomogeneous solar cells is possible. It can be reliably predicted how a cell would improve if certain defects could be avoided. This method is implemented in a software code, which is available.

Calcium transport in turtle bladder

1987 ◽  
Vol 253 (6) ◽  
pp. R917-R921
Author(s):  
S. Sabatini ◽  
N. A. Kurtzman
Keyword(s):  
Calcium Transport ◽  
Calcium Absorption ◽  
Short Circuit ◽  
Open Circuit ◽  
Calcium Flux ◽  
Bladder Epithelium ◽  
Control Value ◽  
Sodium Calcium ◽  
Turtle Bladder ◽  
Absorptive Flux

Unidirectional 45Ca fluxes were measured in the turtle bladder under open-circuit and short-circuit conditions. In the open-circuited state net calcium flux (JnetCa) was secretory (serosa to mucosa) and was 388.3 +/- 84.5 pmol.mg-1.h-1 (n = 20, P less than 0.001). Ouabain (5 X 10(-4) M) reversed JnetCa to an absorptive flux (serosal minus mucosal flux = -195.8 +/- 41.3 pmol.mg-1.h-1; n = 20, P less than 0.001). Amiloride (1 X 10(-5) M) reduced both fluxes such that JnetCa was not significantly different from zero. Removal of mucosal sodium caused net calcium absorption; removal of serosal sodium caused calcium secretion. When bladders were short circuited, JnetCa decreased to approximately one-third of control value but remained secretory (138.4 +/- 54.3 pmol.mg-1.h-1; n = 9, P less than 0.025). When ouabain was added under short-circuit conditions, JnetCa was similar in magnitude and direction to ouabain under open-circuited conditions (i.e., absorptive). Tissue 45Ca content was approximately equal to 30-fold lower when the isotope was placed in the mucosal bath, suggesting that the apical membrane is the resistance barrier to calcium transport. The results obtained in this study are best explained by postulating a Ca2+-ATPase on the serosa of the turtle bladder epithelium and a sodium-calcium antiporter on the mucosa. In this model, the energy for calcium movement would be supplied, in large part, by the Na+-K+-ATPase. By increasing cell sodium, ouabain would decrease the activity of the mucosal sodium-calcium exchanger (or reverse it), uncovering active calcium transport across the serosa.

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