Effect of Wall Charge on Striation in Plasma Display Cells

Different configurations and driving voltages have been employed to investigate the effect of the wall charge on the striations in macroscopic plasma display panel （PDP） cells. The experimental results show that a discharge channel near the dielectric layer is indispensable to striation occurring in the anode area during a discharge, while the pre-accumulated charge on the dielectric layer and the surface state are not important. The origin of the striation is related only to the physical process in the cell. The dielectric layer acts as a charge collector during a PDP discharge.

A New Method for Measuring the Wall Charge Waveforms of AC PDP

A new method is developed to measure the wall charge waveforms in coplanar alternating current plasma display panel (AC PDP). In the method, two groups of display electrodes are selected from a coplanar AC PDP and two capacitors are respectively connected with these two groups of display electrodes in series, and a measuring circuit and a reference circuit are thus constructed. With the help of special processing, discharge takes place in the cells included in the measuring circuit under a normal drive voltage but no discharge takes place in the cells included in the reference circuit under a normal drive voltage. The wall charge waveforms are obtained from the voltage difference between the two capacitors. Using the method, the wall charge waveforms are measured during resetting period, addressing period and sustaining period for the 304.8mm (12-inch) test PDP panel. The result shows that the wall voltage is about 96V during the sustaining period.

Formation mechanism of bright and dark concentric-ring pattern in dielectric barrier discharge

In this work,a bright and dark concentric-ring pattern is reported in a dielectric barrier discharge for the first time.The spatiotemporal dynamics of the bright and dark concentric-ring pattern are investigated with an intensified charge-coupled device and photomultiplier tubes.The results indicate that the bright and dark concentric-ring pattern is composed of three concentric-ring sublattices.These are bright concentric-ring structures,dark concentric-ring structures and wider concentric-ring structures,respectively.The bright concentric-ring structures and dark concentricring structures are alternately distributed.The bright concentric-ring structures are located at the centre of the wider concentric-ring structures.The wider concentric-ring structures first form from the outer edge and gradually develop to the centre.The essence of all three concentric-ring structures is the individual discharge filaments.The optical emission spectra of different sublattices are acquired and analysed.It is found that the plasma parameters of the three concentricring sublattices are different.Finally,the formation mechanism of the bright and dark concentricring pattern is discussed.

Spatio-Temporal Distribution of Individual Filaments in a Square Superlattice Pattern in Atmospheric Dielectric Barrier Discharge

Spatio-temporal distribution of individual filament in a square superlattice pattern, which consists of large and small spots （filaments）, is studied in atmospheric dielectric barrier discharges. The spatial distributions of the two discharges for individual large filament along the direction perpendicular to the electrode are estimated by the distributions of light signals along the electrode. It is found that the discharge at the rising edge of the applied voltage is with a wider column, weaker current, and longer current pulse duration in comparison with that at the falling edge

Ferroelectric engineering:Enhanced thermoelectric performance by local structural heterogeneity

Although traditional ferroelectric materials are usually dielectric and nonconductive,GeTe is a typical ferroelectric semiconductor,possessing both ferroelectric and semiconducting properties.GeTe is also a widely studied thermoelectric material,whose performance has been optimized by doping with various elements.However,the impact of the ferroelectric domains on the thermoelectric properties remains unclear due to the difficulty to directly observe the ferroelectric domains and their evolutions under actual working conditions where the material is exposed to high temperatures and electric currents.Herein,based on in-situ investigations of the ferroelectric domains and domain walls in both pure and Sb-doped GeTe crystals,we have been able to analyze the dynamic evolution of the ferroelectric domains and domain walls,exposed to an electric field and temperature.Local structural heterogeneities and nano-sized ferroelectric domains are generated due to the interplay of the Sb^(3+)dopant and the Ge-vacancies,leading to the increased number of charged domain walls and a much improved thermoelectric performance.This work reveals the fundamental mechanism of ferroelectric thermoelectrics and provides insights into the decoupling of previously interdependent properties such as thermo-power and electrical conductivity.