scholarly journals Deep Electrical Modulation of Terahertz Wave Based on Hybrid Metamaterial-Dielectric-Graphene Structure

2019 ◽  
Vol 9 (3) ◽  
pp. 507 ◽  
Author(s):  
Liangping Xia ◽  
Xin Zhang ◽  
Man Zhang ◽  
Suihu Dang ◽  
Shijian Huang ◽  
...  
Keyword(s):  
Modulation Depth ◽  
Active Material ◽  
Terahertz Wave ◽  
Experimental Result ◽  
Metallic Structure ◽  
Electrical Field ◽  
Electrical Modulation ◽  
Hybrid Metamaterial ◽  
Modulation Voltage ◽  
Applied Electrical Field

A terahertz modulation structure based on hybrid metamaterial and graphene is proposed and demonstrated in this work. The metamaterial with a square slit ring array excites terahertz resonance in the slits and enhances the interaction between the terahertz wave and graphene. The graphene layer acting as the active material is tuned by the applied electrical field. With the separation by a dielectric layer between the graphene and the metallic structure, the resonant frequency and transmitted energy are both modulated by the graphene. Experimental result indicates that the modulation depth of the terahertz transmitted amplitude is 65.1% when the applied modulation voltage is tuned 5 V.

scholarly journals Influence of Multivector Field on Paste Preparation and Formation of Negative Electrodes of Lead Batteries

Batteries ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 24
Author(s):  
Boris Shirov ◽  
Vesselin Naidenov ◽  
Urii Markov
Keyword(s):  
Active Material ◽  
Negative Electrode ◽  
Limiting Factors ◽  
Skeletal Structure ◽  
Experimental Result ◽  
External Application ◽  
Electrochemical Processes ◽  
Depth Of Discharge ◽  
Negative Electrodes ◽  
Positive Effect

During the operation of the negative electrode, some critical processes take place, which are limiting factors for the operation of lead–acid batteries. To improve the efficiency of the negative active material and minimize these processes, external application of multivector field is proposed. Two applications of the multivector field are studied: during negative paste preparation and during formation. It is established that, when applying multivector field during negative paste preparation, the chemical processes proceed more efficiently. The results are better phase composition and crystallinity of the cured paste, thus increasing the capacity of the consequently built lead batteries by 12% on average. The application of a multivector field during the formation of negative active materials in lead batteries has a positive effect on the skeletal structure, the size and shape of the Pb crystals. This ensures longer service life, which is confirmed by the 17.5% Depth of Discharge continuous tests on 12 V/75 Ah batteries. The batteries formed under the influence of external multivector field showed 20% longer cycle life. Based on the experimental result, a most probable mechanism of the influence of the multivector field on the chemical and electrochemical processes in lead batteries during negative paste preparation and formation of negative active masses is proposed.

scholarly journals Preparation of Fe3O4-Ag Nanocomposites with Silver Petals for SERS Application

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1288
Author(s):  
Thi Thuy Nguyen ◽  
Fayna Mammeri ◽  
Souad Ammar ◽  
Thi Bich Ngoc Nguyen ◽  
Trong Nghia Nguyen ◽  
...  
Keyword(s):  
Self Assembly ◽  
Hot Spots ◽  
Surface Enhanced Raman Spectroscopy ◽  
Electrical Field ◽  
Stabilizing Agents ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Sers Sensing ◽  
Applied Electrical Field ◽  
Positively Charged

The formation of silver nanopetal-Fe3O4 poly-nanocrystals assemblies and the use of the resulting hetero-nanostructures as active substrates for Surface Enhanced Raman Spectroscopy (SERS) application are here reported. In practice, about 180 nm sized polyol-made Fe3O4 spheres, constituted by 10 nm sized crystals, were functionalized by (3-aminopropyl)triethoxysilane (APTES) to become positively charged, which can then electrostatically interact with negatively charged silver seeds. Silver petals were formed by seed-mediated growth in presence of Ag+ cations and self-assembly, using L-ascorbic acid (L-AA) and polyvinyl pyrrolidone (PVP) as mid-reducing and stabilizing agents, respectively. The resulting plasmonic structure provides a rough surface with plenty of hot spots able to locally enhance significantly any applied electrical field. Additionally, they exhibited a high enough saturation magnetization with Ms = 9.7 emu g−1 to be reversibly collected by an external magnetic field, which shortened the detection time. The plasmonic property makes the engineered Fe3O4-Ag architectures particularly valuable for magnetically assisted ultra-sensitive SERS sensing. This was unambiguously established through the successful detection, in water, of traces, (down to 10−10 M) of Rhodamine 6G (R6G), at room temperature.

scholarly journals Effective Generation of Milliwatt-Level Sub-Terahertz Wave for Nonlinear Response Measurement of Two-Dimensional Material by Optical Heterodyne Technique

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Shuqing Chen ◽  
Zhiqiang Xie ◽  
Junmin Liu ◽  
Yanliang He ◽  
Yao Cai ◽  
...  
Keyword(s):  
Nonlinear Response ◽  
Modulation Depth ◽  
Terahertz Wave ◽  
Saturable Absorption ◽  
Optical Heterodyne ◽  
Two Dimensional ◽  
Response Measurement ◽  
Microwave Source ◽  
Terahertz Band ◽  
Heterodyne Technique

By using optical heterodyne technique, we demonstrated the stable emission of sub-terahertz wave with the frequency ranging from 88 GHz to 101 GHz, which can operate as microwave source for nonlinear response measurement system. Mutual frequency beating of two well-separated sideband signals at a 0.1 THz photo-detector (PD) allows for the generation of sub-terahertz signal. Based on this approach, we have achieved the radiation of 0.1 THz wave with power up to 4 mW. By transmittance measurement, two-dimensional nanomaterial topological insulator (TI: Bi2Te3) shows saturable absorption behaviors with normalized modulation depth of 47% at 0.1 THz. Our results show that optical heterodyne technique could be developed as an effective microwave source generation for nonlinear measurement at sub-terahertz, even terahertz band.

Spinal neurite reabsorption and regrowth in vitro depend on the polarity of an applied electric field

Development ◽  
1987 ◽  
Vol 100 (1) ◽  
pp. 31-41
Author(s):  
C.D. McCaig
Keyword(s):  
Electric Field ◽  
Neural Tube ◽  
Applied Field ◽  
Growth Cones ◽  
Individual Growth ◽  
Electrical Field ◽  
Field Reversal ◽  
Specific Change ◽  
Applied Electrical Field

Retraction and regrowth of frog neural tube neurites have been studied in vitro in control cultures and in the presence of a small, continuously applied electrical field. In control cultures, some degree of retraction was seen in 39% of neurites while 7% were reabsorbed completely. Reabsorption of anodal-facing neurites was at least twice as common, with 67% showing some retraction and 17% almost totally reabsorbed. Cathodal-facing neurites were spared from retraction. Following extreme reabsorption of anodal-facing neurites, reversal of the electric field promoted regeneration in 47% (9/19) of cases studied. growth cone morphology also was determined by the polarity of the applied field. Anodal-facing growth cones had fewer filopodia than cathodal-facing growth cones sharing the same cell body. Field reversal induced a polarity-specific change in filopodia number on individual growth cones: a shift from anodal to cathodal increased filopodia numbers and vice versa. Some possible mechanisms involved and the significance of these results are discussed.

Q-switched all-fiber laser based on MoSe2 films with chemical vapor deposition method

2019 ◽  
Vol 28 (02) ◽  
pp. 1950019 ◽  
Author(s):  
Xin Zhang ◽  
Yanli Yao ◽  
Shubin Wang ◽  
Guoli Ma ◽  
Ming Lei ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Modulation Depth ◽  
Chemical Vapor ◽  
Experimental Result ◽  
Chemical Vapor Deposition Method ◽  
Absorption Characteristic ◽  
Saturable Absorption ◽  
Deposition Method ◽  
Optical Modulators

In this work, MoSe2 film is synthesized by the chemical vapor deposition method. Saturable absorber (SA) is assembled with the tapered fiber and MoSe2 films. Q-switched operation is achieved with the MoSe2-based SA. The experimental result reveals that the MoSe2-based SA has excellent saturable absorption characteristic with 23.41% modulation depth. When the pump power is greater than 289.2[Formula: see text]mW, Q-switched all-fiber lasing action is demonstrated. The repetition rate of the Q-switched pulses varies from 185.6 to 252.8[Formula: see text]kHz. The shortest pulse duration is 801.9[Formula: see text]ns, and the largest output energy is 69.3[Formula: see text]nJ. Results indicate that MoSe2 films can provide new opportunities for large-modulation-depth optical modulators in ultrafast photonics.

NIR Light Driven Terahertz Wave Modulator with a Large Modulation Depth Based on a Silicon‐PEDOT:PSS‐Perovskite Hybrid System

2020 ◽  
Vol 5 (4) ◽  
pp. 1901090
Author(s):  
Weien Lai ◽  
Chengda Ge ◽  
Hao Yuan ◽  
Qingfeng Dong ◽  
Deren Yang ◽  
...  
Keyword(s):  
Hybrid System ◽  
Modulation Depth ◽  
Terahertz Wave ◽  
Nir Light

scholarly journals Understanding Collaborative Effects between the Polymer Gel Structure and the Applied Electrical Field in Gel Electrophoresis Separation

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Jennifer A. Pascal ◽  
Koteswara Rao Medidhi ◽  
Mario A. Oyanader ◽  
Holly A. Stretz ◽  
Pedro E. Arce
Keyword(s):  
Gel Electrophoresis ◽  
Chemical Properties ◽  
Polymer Gels ◽  
Optimal Time ◽  
Polymer Gel ◽  
Gel Structure ◽  
Electrical Field ◽  
Standard Case ◽  
Similar Chemical ◽  
Applied Electrical Field

The collaborative effects between an applied orthogonal electrical field and the internal structure of polymer gels in gel electrophoresis is studied by using microscopic-based electrophoretic transport models that then are upscaled via the format of electro kinetics-hydrodynamics (EKHD). The interplay of the electrical field and internal gel morphology could impact the separation of biomolecules that, because of similar chemical properties, are usually difficult to separate. In this study, we focus on an irregular pore geometry of the polymer-gel structure by using an axially varying pore (i.e., an axially divergent section) and an orthogonal (to the main flow of solutes) applied electrical field. The microscopic-based conservation of species equation is formulated for the standard case of electrophoresis of charged particles within a geometrical domain, i.e., a pore, and upscaled to obtain macroscopic-based diffusion and mobility coefficients. These coefficients are then used in the calculation of the optimal time of separation to study the effect of the varying parameters of the pore structure under different values of the electrical field. The results are qualitatively consistent with those reported, in the literature, by using computational-based approaches as well as with experiments also reported in the literature, previously. The study shows the important collaborative effects between the applied electrical field and the internal geometry of the polymer gels that could lead to improving biomolecule separation in gel electrophoresis.

Basic Study on Electro-Adhesive Surface Applying 3-Dimensional Micro Structures

2016 ◽  
Vol 10 (1) ◽  
pp. 48-54 ◽  
Author(s):  
Soichiro Yamada ◽  
◽  
Ryo Koike ◽  
Shintaro Arano ◽  
Yasuhiro Kakinuma ◽  
...  
Keyword(s):  
Particle Distribution ◽  
Structure Design ◽  
Experimental Result ◽  
Electrical Field ◽  
Basic Study ◽  
3 Dimensional ◽  
Silicone Gel ◽  
Adhesive Surface ◽  
Adhesion Performance ◽  
Micro Structures

Electro Adhesive Gel (EAG) has the unique characteristic of changing its surface adhesive property with the intensity of the electrical field applied. This property makes EAG useful in applications to fixing devices and mechanical brakes. Although its adhesion performance depends on the distribution of the electro-rheological particles in the EAG, it is difficult to arrange the particle distribution uniformly in a wide area from the perspective of production process. In this study, a novel functional elastomer that has the same function as EAG is developed, Electro Adhesive Surface (EAS). In EAS, micro photolithography is used to fabricate strut pyramids distributed uniformly on a substrate, and then silicone gel is poured into the structure. When an electrical field is applied, the silicone gel rises to the tops of the pyramids formed by the struts, and adhesion occurs to an object on EAS. To determine a micro structure design for EAS, the fixing force was measured with various struts diameter and gaps. Experimental result shows that the larger struts diameter and the narrower gaps enhance the fixing force of EAS.

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