High-intensity Electric Fields Research Articles

Set-Point Identification and Robustness Testing of a Triboelectrostatic Separation Process for Mixed Granular Plastics

The vibratory feeders had already been proven to be efficient devices for tribocharging granular plastics in view of their separation in high-intensity electric fields. In this paper, the vibratory feeder was used as a tribocharger operating with a free-fall electrostatic separator. There are two aims at embarking on the study: (1) formulate recommendations regarding the optimum values of three control variables of the separator; and (2) assess the robustness of the triboelectrostatic separation. The 50%-ABS-50%-HIPS mixture of 4-mm-size granules employed in the experiments is typical for the recycling of plastics from waste electrical and electronic equipment. The investigation was conducted according to a composite factorial experimental design, and it revealed that the separation efficiency significantly depends on the high-voltage applied to the electrode system and on the position of the splitters that define the geometry of the product collector, but is less affected by the material transport velocity on the tray of the vibratory feeder. Using Taguchi's methodology, it was possible to predict the most robust process design, with respect to the uncontrolled variation of granule size and ABS content. The former of these “noise” factors has a significant effect on the outcome of the process, whereas the latter has little influence on separation efficiency.

Evaluation of distributed-type inorganic electroluminescence devices using comb-shaped electrodes

We deposited comb-shaped metal electrodes with narrow gaps on a glass substrate and succeeded in achieving a high electric field intensity. Using conventional structures, this result could only be achieved by applying transparent electrodes, and in this study, we used a comb-shaped metal (Au) electrode and a comb-shaped indium tin oxide (ITO) electrode. When we measured the luminescence from the opposite side of the comb-shaped electrodes, at 15 V/µm, the luminance in the ITO electrode sample was identical (92–95 cd/m2) to that measured from the side of the comb-shaped electrodes. Conversely, a 111-cd/m2 brightness (a 1.9-fold increase) was observed from the opposite side of the Au electrode. Electrode transmittance was unnecessary when the luminescence was observed from the opposite side of the comb-shaped electrodes, and by using metals such as Au, it was possible to produce a display that did not require transparent electrodes. Finally, we simulated the electric field distribution for the inorganic electroluminescence (EL) using comb-shaped electrodes by semiconductor device simulator Atlas.

Nanoscale plasmonic stamp lithography on silicon.

Nanoscale lithography on silicon is of interest for applications ranging from computer chip design to tissue interfacing. Block copolymer-based self-assembly, also called directed self-assembly (DSA) within the semiconductor industry, can produce a variety of complex nanopatterns on silicon, but these polymeric films typically require transformation into functional materials. Here we demonstrate how gold nanopatterns, produced via block copolymer self-assembly, can be incorporated into an optically transparent flexible PDMS stamp, termed a plasmonic stamp, and used to directly functionalize silicon surfaces on a sub-100 nm scale. We propose that the high intensity electric fields that result from the localized surface plasmons of the gold nanoparticles in the plasmonic stamps upon illumination with low intensity green light, lead to generation of electron-hole pairs in the silicon that drive spatially localized hydrosilylation. This approach demonstrates how localized surface plasmons can be used to enable functionalization of technologically relevant surfaces with nanoscale control.

Study of strong dipole and quadrupole plasmon resonance in Ag nanorings antenna

Self-organized Ag nanorings antenna were formed on quartz glass wafers by a simple chemistry reaction without any template. By using absorption measurements and three-dimensional finite-difference time-domain (3D-FDTD) calculations, the dipole and quadrupole plasmon resonances of Ag nanorings antenna were investigated experimentally and theoretically. Calculations have shown that large electric fields are confined at the quadrupole of the Ag nanoring, leading to quadrupole plasmon resonances. Compared the electric enhancement factor of the exterior surfaces of Ag nanoring, the electric enhancement factor of the interior surface is about six times excited by an incident light with 514.5 nm wavelength. Furthermore, the highest electric-field intensity of Ag nanorings is around four times larger than that for Ag nanodome with the same condition. These results pave the way to design plasmonic nanostructures for practical applications that require metallic nanoparticles with enhanced electric fields.

High risk breast cancer: Prospective data about the role of FDG PET/CT in pre- and post-operative settings

15 mg/m 2 was given, electroporation was performed by administration of pulsed high-intensity electric fields, in 20 minutes. Patient was discharged on POD 1. No early side effect was observed. Pathology showed a partial tumor regression (TRG3) confined to the mucosal layer. Main results: Patient underwent a careful follow up. One month after the procedure, he suffered from major fecal incontinence and proctoscopy showed a large rectal ulcer in the field of ECT. PET scan showed an increase of SUV. Patient refused abdominoperineal excision at all. Three months later, digital examination and proctoscopy showed a complete rectal mucosal healing, with a minimal residual scar and PET scan showed a minimal SUV. At the last follow up, 10 months after ECT, these results were confirmed. Fecal incontinence resolved completely. Conclusion: ECT has been proven effective in the treatment of cutaneous and subcutaneous tumors: its role in the palliative treatment of small low rectal tumors after neoadjuvant therapy is promising.

Flowing electrolytic synthesis of fluorescent carbon nanoparticles and carbon nanosheets

A flowing electrolytic device equipped with large electrode area and high electric field intensity was designed for the preparation of fluorescent carbon nanoparticles (CNPs) and carbon nanosheets (CNSs). Comparing with normal electrolysis, the flowing electrolysis showed higher efficiency for the preparation and separation of the products. In the high intensity electric field, the CNPs and CNSs were enriched to the flowing electrolyte and the anode surface respectively. The obtained CNPs were regarded as a fluorescent probe of Fe3+, and the CNSs modified electrode was fabricated to be an electrochemical sensor of acetaminophen for its electrocatalytic properties. So the CNPs and CNSs were expected for the application of fluorescent and electrochemical detection.

Nonlinear electron dynamics of gold ultrathin films induced by intense terahertz waves

Linear and nonlinear electron dynamics of polycrystalline gold (Au) ultrathin films with thicknesses ranging from 1.4 to 5.8 nm were investigated via transmittance terahertz (THz) spectroscopy with intense electric field transients. We prepared ultrathin films with low surface roughness formed on a Si–(7 × 7) reconstructed surface, leading to the observation of monotonic decrease in THz transmittance with respect to film thickness. Furthermore, at all tested thicknesses, the transmittance decreased nonlinearly by 10%–30% with the application if high-intensity THz electric fields. Based on a Drude-model analysis, we found a significant decrease in the damping constant induced by the THz electric field, indicating that electrons are driven beyond the polycrystalline grain boundaries in Au thin films, and consequently leading to the suppression of the electron–boundary scattering rate.

Characteristics investigation of Ni-diamond composite electrodeposition

Parameters of stirring rate and temperature were designed based on electrochemical testings of cathodic polarization, electrochemical impedance spectroscopy and defferential capacitance. At the same time electrochemical action of diamond particles in the bath was studied. Interface force per unit area between particle and cathode was calculated in order to analyse the mechanism of composite electrodeposition. And then Ni-diamond composite coatings with 1.47–15.6wt.% particle content were prepared by composite electrodeposition technique in typical Watt's bath. Resultof electrochemical measurements revealed that mass fraction of codeposited diamond particles at medium stirring rate is higher than those of high and low stirring rate. Technics experiments confirmed the foretaste well. It was proved that electrochemical testing is significant for parameter designment. It was also detected that fraction of coverage θNF which had effect on non-Faraday admittance could reflect more efficiently on particle content in coating compared with fraction of coverage θF which interfered with Faraday admittance. Interface force per unit area was found to be the key for particle to entry into coating since 3.57% particles were rooted in matrix metal at just 0.0252% coating thickness/particle size. Interim stirring designed according to interface force mechanism increased the weight percentage of diamond particles in coating. The mechenism could explain the effect of particle size on particle content in coating. Calculation results show that the interface force per unit area for Ni-diamond system was close to 3.3×103N/m2. Furthermore, composite electrodeposite process can be divided into three steps. Firstly, diamond particles adsorbing positive charges are direct transported toward cathodic surface due to stirring. Secondly, a tremendous amount of particles temporary attaching on cathode are scoured back into the bath by particles in the bath and flowing solution. A few particles root quickly in coating depending on interface pressure after formation of interface between particle and fresh nickel coating with the help of high electric field intensity of electric double layer. Finally, particles are buried slowly by fresh nickel coating.

Cross-Sectional Optimization of Whispering-Gallery Mode Sensor With High Electric Field Intensity in the Detection Domain

Optimal cross-sectional shapes for whispering-gallery mode sensors with prescribed emission wavelengths and resonance modes are generated through topology optimization based on the finite element method. The sensor is assumed to detect the state of the domain surrounded by the sensor. We identified the integral of the square of the electric field intensity over the detection domain and the quality factor (Q factor), which should be maximized, as key values for the sensor sensitivity, representing the detection limit for the relative permittivity change of the test object. Based on this, the integral of the square of the electric field intensity over the detection domain and the Q factor are studied as the optimization targets. In our numerical study, their optimal configuration characteristics are identified and analyzed. The resulting device has a small radius, a small detection domain and a concave shape with a center located next to the detection domain. We also succeeded in performing simultaneous optimization of the integral of the square of the electric field intensity over the detection domain and the Q factor.

Structure and properties of (1 − x)BiFeO3 · xPbFe2/3W1/3O3 (0 ≤ x ≤ 1) solid solutions

(1 − x)BiFeO3 · xPbFe2/3W1/3O3 ((1 − x)BFO · xPFWO) samples with 0 ≤ x ≤ 1 have been prepared by a standard ceramic processing technique and characterized by X-ray diffraction, dielectric measurements, and Mossbauer spectroscopy. The system has been shown to contain a continuous series of perovskite solid solutions. The solid solutions in the range 0 ≤ x < 0.32 have a rhombohedral structure and those with 0.32 ≤ x ≤ 1 have a cubic structure. Increasing the BFO content from 0 to 40% leads to rapid degradation of the dielectric permittivity peak that occurs at 180 K in PFWO and is due to the relaxor behavior of this component. At higher BFO concentrations, the electrical conductivity of the solid solutions increases by about two orders of magnitude. The temperature dependences of permittivity for the samples containing ∼80% BFO have prominent maxima around 430 and 520 K, whose position is frequency-independent. The solid solutions exhibited no piezoelectric or pyroelectric effect, probably because they were insufficiently poled in a field of 10 kV/cm at 300 K. At higher electric field intensities, the samples experienced breakdown.

Impedance matching network systems using stub-lines of 20 kW CW RF amplifier for SKKUCY-9 compact cyclotron

The SKKUCY-9 is a compact cyclotron for radioactive isotopes (RI) production of positron emission tomography (PET). Charged particles such as H-ions are accelerated azimuthally within a high intensity electric field (E-field) generated from a radio frequency (RF) system in cyclotron. A high power RF signal is transmitted from an RF amplifier to an RF resonating cavity. The RF system of the SKKUCY-9 operates in continuous wave (CW) mode. If an ion beam were accelerated in the cyclotron, the vacuum level and permittivity would be changed because of beam loading. It causes an impedance shift of the RF resonating cavity. This impedance mismatch generates reflected power that decreases the RF transmitting power. To prevent this situation, an impedance matching system is necessary.This paper describes the impedance matching system of a 20kW RF amplifier in an SKKUCY-9 compact cyclotron. The impedance matching circuit was designed using both an input stage and output stage, which are divided between the cathode and anode in a vacuum tube that is used as an amplifying device. The equivalent circuit of the matching system is made of passive elements. The characteristic results of designed circuit were calculated using a Smith chart. In assembling, the inductors were replaced by movable stub-line structures. The dimensions of the stub-line structures were optimized with equations and the measurement results. The experiment was performed to find the result values of matching circuit impedance and RF power amplitude.

The Preparation of Electrohydrodynamic Bridges from Polar Dielectric Liquids

Horizontal and vertical liquid bridges are simple and powerful tools for exploring the interaction of high intensity electric fields (8-20 kV/cm) and polar dielectric liquids. These bridges are unique from capillary bridges in that they exhibit extensibility beyond a few millimeters, have complex bi-directional mass transfer patterns, and emit non-Planck infrared radiation. A number of common solvents can form such bridges as well as low conductivity solutions and colloidal suspensions. The macroscopic behavior is governed by electrohydrodynamics and provides a means of studying fluid flow phenomena without the presence of rigid walls. Prior to the onset of a liquid bridge several important phenomena can be observed including advancing meniscus height (electrowetting), bulk fluid circulation (the Sumoto effect), and the ejection of charged droplets (electrospray). The interaction between surface, polarization, and displacement forces can be directly examined by varying applied voltage and bridge length. The electric field, assisted by gravity, stabilizes the liquid bridge against Rayleigh-Plateau instabilities. Construction of basic apparatus for both vertical and horizontal orientation along with operational examples, including thermographic images, for three liquids (e.g., water, DMSO, and glycerol) is presented.

The preparation of electrohydrodynamic bridges from polar dielectric liquids.

Horizontal and vertical liquid bridges are simple and powerful tools for exploring the interaction of high intensity electric fields (8-20 kV/cm) and polar dielectric liquids. These bridges are unique from capillary bridges in that they exhibit extensibility beyond a few millimeters, have complex bi-directional mass transfer patterns, and emit non-Planck infrared radiation. A number of common solvents can form such bridges as well as low conductivity solutions and colloidal suspensions. The macroscopic behavior is governed by electrohydrodynamics and provides a means of studying fluid flow phenomena without the presence of rigid walls. Prior to the onset of a liquid bridge several important phenomena can be observed including advancing meniscus height (electrowetting), bulk fluid circulation (the Sumoto effect), and the ejection of charged droplets (electrospray). The interaction between surface, polarization, and displacement forces can be directly examined by varying applied voltage and bridge length. The electric field, assisted by gravity, stabilizes the liquid bridge against Rayleigh-Plateau instabilities. Construction of basic apparatus for both vertical and horizontal orientation along with operational examples, including thermographic images, for three liquids (e.g., water, DMSO, and glycerol) is presented.

Effects of static electric fields on growth and development of wheat aphid Sitobion aveanae (Hemiptera: Aphididae) through multiple generations

Insects show a variety of responses to electric fields and most of them are associated with immediate effects. To investigate the long-term effects of static electric field on the wheat aphid Sitbion avenae, the insert was exposed to 4 min of a static electric field at intensities of 0, 2, 4, or 6 kV/cm. Development effects over 30 consecutive generations of the insect were studied. The results showed that the electric field could exert adverse effects on the developmental duration and total longevity of S. avenae nymphs regardless of exposure intensities or generations. The effects appeared to be more intense and fluctuated at higher electric field intensities and more insect generations. The most favorable exposure for development was 6 kV/cm for 4 min while the most detrimental electric fields were 2 kV/cm for 4 min and 4 kV/cm for 4 min. Among the treatments, the first instar duration was significantly prolonged while the adult longevities were significantly shortened in the sixth generation. The intrinsic rate of increase and net reproductive rate in the sixth generation were also the lowest among the 30 consecutive generations studied. Based on the results, the adverse effects of electric fields on insects may be used in the bio-control of pest insects in terms of pest management.

Assessment of Electric Field Distribution Inside 500/220 kV Open Distribution Substations during Working Conditions

The high level electric field intensity produced by high voltage (HV) equipments inside 500/220 kV substations is harmful for the human (staff) health. Therefore the minimum health and safety requirements regarding the exposure of workers to the risk arising from electric fields produced inside these substations is still considered as a competitive topic for utility designers, world health organization (WHO) and biomedical field researchers. It is very important to have knowledge about levels distribution of electric field intensity within these high voltage substations as early stage in the process of substation design. This paper presents results of investigation 50Hz electric field intensity distribution inside 500/220 kV power transmission substations in Cairo, Egypt. This paper presents a method for assessment the distribution of 50HZ electric field intensity distribution inside this substation, this method of analysis is based on the charge simulation technique (CSM). This study will serve for planning service works or for inspection of equipment on HV power transmission substations.

Assessment of Electric Field Distribution Inside 500/220 kV Open Distribution Substations during Working Conditions

The high level electric field intensity produced by high voltage (HV) equipments inside 500/220 kV substations is harmful for the human (staff) health. Therefore the minimum health and safety requirements regarding the exposure of workers to the risk arising from electric fields produced inside these substations is still considered as a competitive topic for utility designers, world health organization (WHO) and biomedical field researchers. It is very important to have knowledge about levels distribution of electric field intensity within these high voltage substations as early stage in the process of substation design. This paper presents results of investigation 50Hz electric field intensity distribution inside 500/220 kV power transmission substations in Cairo, Egypt. This paper presents a method for assessment the distribution of 50HZ electric field intensity distribution inside this substation, this method of analysis is based on the charge simulation technique (CSM). This study will serve for planning service works or for inspection of equipment on HV power transmission substations.

Flat panel detector based on a shadow mask plasma display panel

AbstractA flat panel detector based on the structure of a shadow mask plasma display panel is analyzed in terms of the electron amplification factor when used in the Townsend mode. The detector consists of a metal shadow mask and two ultra‐thin glass substrates with electrodes depositing on them. The shadow mask divides the detecting area into arrays of independent cells. The electron gain and linearity of the device are investigated by simulation based on the particle‐in‐cell/Monte Carlo collision model. Similar experiments are carried out. Both experimental and simulation results show that the linearity of the detector is significant. The applied voltages and the effective cathode area are parameters affecting its gain. As the avalanche process in the center of the cell with small electric field strength is much smaller than that near the shadow mask edge, the gain increases exponentially with the anode voltage but decreases with the negative shadow mask voltage. The balance between effective cathode area and high electric field intensity near the shadow mask edge provides room for future optimization of the detector. In conclusion, the flat panel detector is a promising component in a detection system for high energy radiation, and the wide application of the device is expected.

Fragmentation and isomerization due to field heating in traveling wave ion mobility spectrometry.

During their travel inside a traveling wave ion mobility cell (TW IMS), ions are susceptible to heating because of the presence of high intensity electric fields. Here, we report effective temperatures Teff,vib obtained at the injection and inside the mobility cell of a SYNAPT G2 HDMS spectrometer for different probe ions: benzylpyridinium ions and leucine enkephalin. Using standard parameter sets, we obtained a temperature of ~800 K at injection and 728 ± 2 K into the IMS cell for p-methoxybenzylpyridinium. We found that Teff,vib inside the cell was dependent on the separation parameters and on the nature of the analyte. While the mean energy of the Boltzmann distributions increases with ion size, the corresponding temperature decreases because of increasing numbers of vibrational normal modes. We also investigated conformational rearrangements of 7+ ions of cytochrome c and reveal isomerization of the most compact structure, therefore highlighting the effects of weak heating on the gas-phase structure of biologically relevant ions.

Effect of surface morphology on the field emission property of ZnO films

AbstractStable and high crystalline quality of ZnO nanocones have been successfully fabricated on glass substrates at room temperature. In 3 min irradiation by argon ion on ZnO thin film surface, ZnO nanocones with a number density of 8‐15 µm‐2 can be observed from SEM images. For a high performance of field emission (FE) device, an emission current stability test was carried out at a fixed electric field of 12 V/µm for 60 min. A stable current of 2.5 µA was observed after 30 min without any obvious irregular current flow. The current density of 1 µA cm‐2 was achieved at 9.8 V/µm and 7.8 V/µm before and after stability test, respectively. Even though some of the ZnO nanocones tip were melted due to Joule heating induced by high intensity of electric field, the field enhancement factor are still comparable with other types of nanostructure emitters. The surface morphology of ZnO nanocones after the stability test showed the nanocones of shorter length are not affected by the high electric field at the emission area in which this revealed the robustness of ZnO compared to CNTs/CNFs. The ZnO nanocones at out of the emission area are also not affected by the high electric field or by any heat generated in the vacuum chamber during field emission. Thus, due to the high thermal and mechanical stability, ZnO nanocones is reliable to be as a promising field emitter. (© 2014 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

Effect of Static High Electric Field Pre-Treatment on Microwave-Assisted Drying of Potato Slices

Dehydration of fruits and vegetables affects their physical, biochemical, and organoleptic properties. In the present study, the effect of static high electric field intensity of 4 kV/cm on drying kinetics of microwave-convective and hot air drying systems was evaluated. The studied electric field intensity had minimal to no effect on the drying kinetics of the potato slices. Less to no curling was observed for high electric field pre-treated samples compared to microwave-convective and hot-air-dried samples. This characteristic was attributed to membrane permeabilization induced by application of a high electric field.