Relationship between BaTiO3 Nanowire Aspect Ratio and the Dielectric Permittivity of Nanocomposites

2014 ◽  
Vol 6 (8) ◽  
pp. 5450-5455 ◽  
Author(s):  
Haixiong Tang ◽  
Zhi Zhou ◽  
Henry A. Sodano
Keyword(s):  
Dielectric Permittivity ◽  
Aspect Ratio

Giant Piezoelectric and Dielectric Relaxations in Statistical Mixtures

2006 ◽  
Vol 115 ◽  
pp. 209-214
Author(s):  
A.I. Chernobabov ◽  
A.V. Turik ◽  
G.S. Radchenko ◽  
S.A. Turik
Keyword(s):  
Dielectric Permittivity ◽  
Aspect Ratio ◽  
Heterogeneous Systems ◽  
Dielectric Constants ◽  
Dielectric Spectra ◽  
Physical Mechanisms ◽  
Dielectric Relaxations ◽  
First Time

The effective complex piezoelectric and dielectric constants of disordered heterogeneous systems of the type of statistical mixtures with the components in the form of spheroid-shaped particles equally oriented but randomly arranged in space were studied. It has been found for the first time that in such systems there appears a giant piezoelectric enhancement accompanied by a giant relaxation of piezoelectric coefficients and the dielectric permittivity. Piezoelectric and dielectric spectra differ significantly from the Debye ones and are of Davidson-Cole type. The influence of the aspect ratio of spheroids on the effects under consideration was studied. The physical mechanisms responsible for the anomalies in the behavior of piezoelectric coefficients and the dielectric permittivity were considered.

Enhanced Energy Storage in Nanocomposites Through Aligned PZT Nanowires

2011 ◽  
Author(s):  
Haixiong Tang ◽  
Henry A. Sodano ◽  
Yirong Lin
Keyword(s):  
Energy Storage ◽  
Energy Density ◽  
Dielectric Permittivity ◽  
Aspect Ratio ◽  
Electric Field ◽  
Applied Electric Field ◽  
Energy Storage And Conversion ◽  
Electromechanical Properties ◽  
Capacitive Energy Storage ◽  
Wide Range

Nanocomposites consisting of a piezoceramic inclusion and polymer matrix offer a combination of electromechanical coupling with high toughness and ductility inherent to polymers. There is a wide range of applications for these types of materials due to their intrinsic piezoelectric and dielectric properties, such as vibration sensing, actuation, energy harvesting and capacitive energy storage. However, the relatively low piezoelectric strain coefficient and dielectric permittivity of these nanocomposites significantly limit their application in energy conversion and energy storage applications. There are mainly two coupled to improve the dielectric permittivity and electromechanical properties of piezoceramic nanocomposites, namely higher aspect ratio active inclusions and alignment of inclusions in the direction of the applied electric field. Previously, we have demonstrated that using higher aspect ratio lead zirconate titanate (PZT) nanowires (NWs) could significantly enhance the energy density and d33 coupling as compared to the samples with lower aspect ratio PZT nanorods [11]. In this paper, we will show that orientation of PZT NWs also influences energy storage capability of nanocomposite. Nanocomposites with aligned PZT NWs in the direction of the applied electric field show increased dielectric permittivity and energy density as compared to those with randomly dispersed inclusions. PZT NWs are hydrothermally synthesized, dispersed into a polyvinylidene fluoride (PVDF), cast into a film and then aligned through uniaxial stretching. Scanning electric microscopy (SEM) shows the PZT NWs are successfully aligned in direction of stretching. This work demonstrates that the energy storage and conversion capability of the nanocomposite can be significantly enhanced through the alignment of PZT NWs in the direction of the applied electric field. The findings of this research could lead to broad interest due to demonstration of developing piezoceramic nanocomposites with enhanced dielectric and electromechanical properties for next generation energy storage and conversion devices.

Giant Dielectric Relaxation in Ordered Matrix Systems Depicted by Maxwell-Garnett Formula

2006 ◽  
Vol 115 ◽  
pp. 203-208
Author(s):  
A.V. Turik ◽  
G.S. Radchenko ◽  
A.I. Chernobabov ◽  
S.A. Turik
Keyword(s):  
Dielectric Permittivity ◽  
Aspect Ratio ◽  
Dielectric Relaxation ◽  
Theoretical Consideration ◽  
Heterogeneous Medium ◽  
Relaxation Processes ◽  
Dielectric Resonance ◽  
Giant Dielectric ◽  
Static Dielectric Permittivity ◽  
The Matrix

A giant enhancement of the static dielectric permittivity and a giant dielectric relaxation in a heterogeneous medium consisting of regularly arranged spheroids distributed in the matrix and described by the Maxwell-Garnett formula were studied. The influence of the inclusions aspect ratio and their concentration is analyzed. The possibility to apply the obtained results to the theoretical consideration of different heterogeneous ferroactive materials is proved. It is shown that observation of the collective dielectric resonance in such media is impossible, and only relaxation processes are the way of obtaining unusual properties of considered materials. Some valuable formulae are derived and discussed.

Modification of MnS inclusion by tellurium in 38MnVS6 micro-alloyed steel

2020 ◽  
Vol 117 (6) ◽  
pp. 615
Author(s):  
Ping Shen ◽  
Lei Zhou ◽  
Qiankun Yang ◽  
Zhiqi Zeng ◽  
Kenan Ai ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Aspect Ratio ◽  
Strong Influence ◽  
Experimental Results ◽  
Alloyed Steel ◽  
Equivalent Diameter ◽  
Small Aspect Ratio ◽  
Steel Quality ◽  
Eds Analysis ◽  
Micro Alloyed Steel

In 38MnVS6 steel, the morphology of sulfide inclusion has a strong influence on the fatigue life and machinability of the steel. In most cases, the MnS inclusions show strip morphology after rolling, which significantly affects the steel quality. Usually, the MnS inclusion with a spherical morphology is the best morphology for the steel quality. In the present work, tellurium was applied to 38MnVS6 micro-alloyed steel to control the MnS inclusion. Trace tellurium was added into 38MnVS6 steel and the effect of Te on the morphology, composition, size and distribution of MnS inclusions were investigated. Experimental results show that with the increase of Te content, the equivalent diameter and the aspect ratio of inclusion decrease strikingly, and the number of inclusions with small aspect ratio increases. The inclusions are dissociated and spherized. The SEM-EDS analysis indicates that the trace Te mainly dissolves in MnS inclusion. Once the MnS is saturated with Te, MnTe starts to generate and wraps MnS. The critical Te/S value for the formation of MnTe in the 38MnV6 steel is determined to be approximately 0.075. With the increase of Te/S ratio, the aspect ratio of MnS inclusion decreases and gradually reaches a constant level. The Te/S value in the 38MnVS6 steel corresponding to the change of aspect ratio from decreasing to constant ranges from 0.096 to 0.255. This is most likely to be caused by the saturation of Te in the MnS inclusion. After adding Te in the steel, rod-like MnS inclusion is modified to small inclusion and the smaller the MnS inclusion, the lower the aspect ratio.

PENINGKATAN KEMAMPUAN GURU BAHASA INDONESIA DALAM MENYUSUN RENCANA PROGRAM PEMBELAJARAN (RPP) SDN 015 PAGARAN TAPAH DARUSSALAM MELALUI METODE PEMBERIAN TUGAS

2017 ◽  
Vol 5 (3) ◽  
pp. 713
Author(s):  
Mukhlis '
Keyword(s):  
Aspect Ratio ◽  
Duty Cycle ◽  
Lesson Plans ◽  
Learning Program ◽  
School Subjects ◽  
Bahasa Indonesia

Based on the observation of some teachers found the symptoms as follows: the lack of abilityof Indonesian teachers in designing learning program (RPP), the learning device is only usedas a supplement and not to the needs of teaching, most teachers again if asked the lessonanswered not have or has not been made. The purpose of this research is to improve theability of Indonesian teachers in designing learning program (RPP) at SDN 015 PagaranTapah Darussalam through the method of administration tasks. This type of research is actionresearch school. Subjects in this study were teachers Indonesian as many as 12 people. Basedon the analysis and discussion can be concluded that the method of administration tasks canimprove the ability of Indonesian teachers in making learning device in SDN 015 PagaranTapah Darussalam through the method of administration tasks. Under these conditions, thelevel of acceptance of teachers increased. The aspect ratio capability Indonesian teachers inpreparing lesson plans through the provision of duty cycle I and II of the increase from 56%and the second cycle to 79%.

Dielectric permittivity in the x-ray region

1978 ◽  
Vol 126 (11) ◽  
pp. 479-513 ◽  
Author(s):  
A.V. Kolpakov ◽  
V.A. Bushuev ◽  
R.N. Kuz'min
Keyword(s):  
Dielectric Permittivity ◽  
X Ray
Sign in / Sign up

Export Citation Format

Share Document