scholarly journals Frequency Response of Induced-Charge Electrophoretic Metallic Janus Particles

Micromachines ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 334 ◽  
Author(s):  
Chong Shen ◽  
Zhiyu Jiang ◽  
Lanfang Li ◽  
James F. Gilchrist ◽  
H. Daniel Ou-Yang

The ability to manipulate and control active microparticles is essential for designing microrobots for applications. This paper describes the use of electric and magnetic fields to control the direction and speed of induced-charge electrophoresis (ICEP) driven metallic Janus microrobots. A direct current (DC) magnetic field applied in the direction perpendicular to the electric field maintains the linear movement of particles in a 2D plane. Phoretic force spectroscopy (PFS), a phase-sensitive detection method to detect the motions of phoretic particles, is used to characterize the frequency-dependent phoretic mobility and drag coefficient of the phoretic force. When the electric field is scanned over a frequency range of 1 kHz–1 MHz, the Janus particles exhibit an ICEP direction reversal at a crossover frequency at ~30 kH., Below this crossover frequency, the particle moves in a direction towards the dielectric side of the particle, and above this frequency, the particle moves towards the metallic side. The ICEP phoretic drag coefficient measured by PFS is found to be similar to that of the Stokes drag. Further investigation is required to study microscopic interpretations of the frequency at which ICEP mobility switched signs and the reason why the magnitudes of the forward and reversed modes of ICEP are so different.

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Valerie Domcke ◽  
Yohei Ema ◽  
Kyohei Mukaida

Abstract We point out an enhancement of the pair production rate of charged fermions in a strong electric field in the presence of time dependent classical axion-like background field, which we call axion assisted Schwinger effect. While the standard Schwinger production rate is proportional to $$ \exp \left(-\pi \left({m}^2+{p}_T^2\right)/E\right) $$ exp − π m 2 + p T 2 / E , with m and pT denoting the fermion mass and its momentum transverse to the electric field E, the axion assisted Schwinger effect can be enhanced at large momenta to exp(−πm2/E). The origin of this enhancement is a coupling between the fermion spin and its momentum, induced by the axion velocity. As a non-trivial validation of our result, we show its invariance under field redefinitions associated with a chiral rotation and successfully reproduce the chiral anomaly equation in the presence of helical electric and magnetic fields. We comment on implications of this result for axion cosmology, focussing on axion inflation and axion dark matter detection.


2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Chunzheng Lv ◽  
Lirong He ◽  
Jiahong Tang ◽  
Feng Yang ◽  
Chuhong Zhang

AbstractAs an important photoconductive hybrid material, perylene/ZnO has attracted tremendous attention for photovoltaic-related applications, but generally faces a great challenge to design molecular level dispersed perylenes/ZnO nanohybrids due to easy phase separation between perylenes and ZnO nanocrystals. In this work, we reported an in-situ reaction method to prepare molecular level dispersed H-aggregates of perylene bisimide/ZnO nanorod hybrids. Surface photovoltage and electric field-induced surface photovoltage spectrum show that the photovoltage intensities of nanorod hybrids increased dramatically for 100 times compared with that of pristine perylene bisimide. The enhancement of photovoltage intensities resulting from two aspects: (1) the photo-generated electrons transfer from perylene bisimide to ZnO nanorod due to the electric field formed on the interface of perylene bisimide/ZnO; (2) the H-aggregates of perylene bisimide in ZnO nanorod composites, which is beneficial for photo-generated charge separation and transportation. The introduction of ordered self-assembly thiol-functionalized perylene-3,4,9,10-tetracarboxylic diimide (T-PTCDI)/ ZnO nanorod composites induces a significant improvement in incident photo-to-electron conversion efficiency. This work provides a novel mentality to boost photo-induced charge transfer efficiency, which brings new inspiration for the preparation of the highly efficient solar cell.


2021 ◽  
Author(s):  
Haidong Li ◽  
Yanyan Song ◽  
Jiyun Zhang ◽  
Jiating He

The application of built-in electric field due to piezoelectric potential is one of the most efficient approaches for photo-induced charge transport and separation. However, the efficiency of converting mechanical energy...


JOUTICA ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 255
Author(s):  
Kemal Farouq Mauladi ◽  
Nurul Fuad

Telecommunications technology is developing very rapidly, ranging from users or engineers. The development of smartphone smartphones is also increasingly in demand, so that the use of electricity needs is also increasing. The need for electricity usage has resulted in more standing voltage in some settlements. The establishment of sutet will have a negative impact on public health. In addition, the influence of electrical energy on humans occurs because the electrical energy generated by electricity generation or electricity that is channeled gives rise to electromagnetic fields. The higher the voltage required by an equipment, the greater the electric field that is distributed. Besides that, it can also find ways to reduce the negative impact of the electric and magnetic fields produced by SUTET which impacts the process of the occurrence of electric and magnetic fields on SUTET. From the problems above, the author intends to determine the effect or correlation between the impact of SUTET on cellphone network transmissions or channels. This research can later determine the negative impact caused by SUTET for the surrounding community, and the impact of SUTET radiation on cellular networks.


2008 ◽  
Vol 74 (1) ◽  
pp. 111-118
Author(s):  
FEN-CE CHEN

AbstractThe acceleration of ions by multiple laser pulses and their spontaneously generated electric and magnetic fields is investigated by using an analytical model for the latter. The relativistic equations of motion of test charged particles are solved numerically. It is found that the self-generated axial electric field plays an important role in the acceleration, and the energy of heavy test ions can reach several gigaelectronvolts.


2021 ◽  
Author(s):  
Karthikeyan Rajagopal ◽  
Irene Moroz ◽  
Balamurali Ramakrishnan ◽  
Anitha Karthikeyan ◽  
Prakash Duraisamy

Abstract A Morris-Lecar neuron model is considered with Electric and Magnetic field effects where the electric field is a time varying sinusoid and magnetic field is simulated using an exponential flux memristor. We have shown that the exposure to electric and magnetic fields have significant effects on the neurons and have exhibited complex oscillations. The neurons exhibit a frequency-locked state for the periodic electric field and different ratios of frequency locked states with respect to the electric field frequency is also presented. To show the impact of the electric and magnetic fields on network of neurons, we have constructed different types of network and have shown the network wave propagation phenomenon. Interestingly the nodes exposed to both electric and magnetic fields exhibit more stable spiral waves compared to the nodes exhibited only to the magnetic fields. Also, when the number of layers are increased the range of electric field frequency for which the layers exhibit spiral waves also increase. Finally the noise effects on the field affected neuron network are discussed and multilayer networks supress spiral waves for a very low noise variance compared against the single layer network.


2020 ◽  
Vol 10 (17) ◽  
pp. 5999
Author(s):  
Min Wang ◽  
Junchen Zou ◽  
Hongli Zhang ◽  
Yuan Wei ◽  
Shulin Liu

This paper shows the results of simulation of features and usability of a proposed method for particle matter (PM) separation detection based on composite electric field. Considering the composite electric field and drag coefficient, a nonlinear dynamic model of particle separation is established. Meanwhile, the model takes into account the changes in the dynamic model caused by the different diameters and different speeds of the particles, and uses the effect of the composite electric field to separate the PM. Numerical simulation results show that the PM diameter, electric field strength, and drag force have significant effects on the separation of particles. Among them, as the drag force decreases, the particle separation displacement gradually increases, and the electric field affects the particle separation direction. In the acceleration room, the particle velocity increases with the increasing of the electric field strength. In the separation room, the displacement of the particulate matter in the Y-axis direction gradually increases from a negative displacement to a positive displacement as the electric field strength increases. The displacement forms a bow shape. When the drag coefficient is changed, the displacement will suddenly increase while it is lower than a certain value. Considering the change of electric field and drag force at the same time, the separation effect would be more obvious when the drag coefficient is smaller. The electric field strength affects the separation direction of the particulate matter.


2020 ◽  
Vol 80 (11) ◽  
Author(s):  
Vladimir Dzhunushaliev ◽  
Vladimir Folomeev

AbstractWe consider non-Abelian SU(3) Proca theory with a Higgs scalar field included. Cylindrically symmetric solutions describing classical tubes either with the flux of a longitudinal electric field or with the energy flux (and hence with nonzero momentum density) are obtained. It is shown that, in quantum Proca theory, there can exist tubes both with the flux of the longitudinal electric field and with the energy flux/momentum density simultaneously. An imaginary particle – Proca proton – in which ‘quarks’ are connected by tubes with nonzero momentum density is considered. It is shown that this results in the appearance of the angular momentum related to the presence of the non-Abelian electric and magnetic fields in the tube, and this angular momentum is a part of the Proca proton spin.


Nanophotonics ◽  
2018 ◽  
Vol 7 (7) ◽  
pp. 1333-1340 ◽  
Author(s):  
Chengkun Yang ◽  
Hao Zhang ◽  
Bo Liu ◽  
Haifeng Liu ◽  
Chao Wang ◽  
...  

AbstractAn electrically tunable whispering gallery mode (WGM) microresonator based on an HF-etched microstructured optical fiber (MOF) infiltrated with dual-frequency liquid crystals (DFLCs) is proposed and experimentally demonstrated for the investigation of the crossover frequency and Freedericksz transition of DFLCs. Experimental results indicate that for applied electric field with operation frequency below the crossover frequency, WGM resonance wavelength decreases with the increment of applied electric field strength. On the contrary, for applied electric field with operation frequency beyond the crossover frequency, WGM resonance dips show red shift as the applied electric field intensity increases. The proposed electrically tunable microcavity integrated with DFLCs is anticipated to find potential applications in optical filtering, all-optical switching, and electrically manipulated bi-directional micro-optics devices.


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