scholarly journals Electromagnetic wave tunneling through an asymmetric three-layer structure containing a conductive negative-permittivity layer

2021 ◽  
Vol 26 (2) ◽  
pp. 3-9
Author(s):  
N. Beletskii ◽  
◽  
S. Borysenko ◽  
Keyword(s):  
Electromagnetic Wave ◽  
Numerical Simulations ◽  
Layer Structure ◽  
Frequency Dispersion ◽  
Negative Permittivity ◽  
Tunneling Effect ◽  
Practical Application ◽  
Layer Structures ◽  
Universal Approach ◽  
The Asymmetry

Subject and Purpose. In the context of growing anticipation of fundamentally new optical and radiophysical devices, the present study is concerned with the total electromagnetic wave tunneling through an asymmetric three-layer structure such that contains a conductive negative-permittivity layer. The aim of this work is to recognize how the asymmetry property of this three-layer structure acts on the effect of total wave tunneling with the frequency dispersion of the conductive negative-permittivity layer taken into account. Methods and Methodology. The frequency-dependent conditions of the total electromagnetic wave tunneling through an asymmetric three-layer structure are sought by numerical simulations. A universal approach based on the introduction of dimensionless frequencies and dimensionless layer thicknesses allows us to numerically investigate conditions of the total electromagnetic wave tunneling for any desired frequencies and geometric parameters of the asymmetric three-layer structure. Results. It has been shown that the asymmetry property of the three-layer structure can significantly change the total electromagnetic wave tunneling conditions. It has been demonstrated that parameters of the asymmetric three-layer structure can be selected in such a way as to modify the total electromagnetic wave tunneling conditions toward a desired practical application of the structure. It has been found that a proper choice of the parameters can minimize the action of the three-layer structure asymmetry on the electromagnetic wave tunneling effect. Conclusion. Asymmetric three-layer structures can be of use to effectively change conditions of the total electromagnetic wave tunneling in an effort to provide devices under development with desired characteristics.

scholarly journals Fabrication of Piezoelectric ZnO Nanowires Energy Harvester on Flexible Substrate Coated with Various Seed Layer Structures

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1433
Author(s):  
Taoufik Slimani Tlemcani ◽  
Camille Justeau ◽  
Kevin Nadaud ◽  
Daniel Alquier ◽  
Guylaine Poulin-Vittrant
Keyword(s):  
Seed Layer ◽  
Layer Structure ◽  
Mechanical Energy ◽  
Flexible Substrate ◽  
Average Power ◽  
Electrical Characterization ◽  
Zno Nanowires ◽  
Device Structure ◽  
Layer Structures ◽  
Electrical Output

Flexible piezoelectric nanogenerators (PENGs) are very attractive for mechanical energy harvesting due to their high potential for realizing self-powered sensors and low-power electronics. In this paper, a PENG that is based on zinc oxide (ZnO) nanowires (NWs) is fabricated on flexible and transparent Polydimethylsiloxane (PDMS) substrate. The ZnO NWs were deposited on two different seed layer structures, i.e., gold (Au)/ZnO and tin-doped indium-oxide (ITO)/ZnO, using hydrothermal synthesis. Along with the structural and morphological analyses of ZnO NWs, the electrical characterization was also investigated for ZnO NWs-based flexible PENGs. In order to evaluate the suitability of the PENG device structure, the electrical output performance was studied. By applying a periodic mechanical force of 3 N, the ZnO NWs-based flexible PENG generated a maximum root mean square (RMS) voltage and average power of 2.7 V and 64 nW, respectively. Moreover, the comparison between the fabricated device performances shows that a higher electrical output can be obtained when ITO/ZnO seed layer structure is adopted. The proposed ZnO NWs-based PENG structure can provide a flexible and cost-effective device for supplying portable electronics.

Restricted Rotational Motion of InterlayerWaterMolecules in Vanadium Pentoxide Hydrate, V2O5·n D2O, as Studied by Deuterium NMR

2002 ◽  
Vol 57 (6-7) ◽  
pp. 419-424 ◽  
Author(s):  
Sadamu Takeda ◽  
Yuko Gotoh ◽  
Goro Maruta ◽  
Shuichi Takahara ◽  
Shigeharu Kittaka
Keyword(s):  
Double Layer ◽  
Vanadium Pentoxide ◽  
Rotational Motion ◽  
Interlayer Space ◽  
Layer Structure ◽  
Bond Distance ◽  
Adsorbed Water ◽  
Deuterium Nmr ◽  
Water Molecules ◽  
Layer Structures

The rotational behavior of the interlayer water molecules of deuterated vanadium pentoxide hydrate, V2O5.nD2O, was studied by solid-state deuterium NMR for the mono- and double-layer structures of the adsorbed water molecules. The rotational motion was anisotropic even at 355 K for both the mono- and double-layer structures. The 180° flipping motion about the C2-symmetry axis of the water molecule and the rotation around the figure axis, which makes an angle Ɵ with the C2-axis, occurred with the activation energy of (34±4) and (49±6) kJmol-1, respectively. The activation energies were almost independent of the mono- and double-layer structures of the water molecules, but the angle Ɵ made by the two axes varied from 33° for the monolayer to 25° for the double-layer at 230 K. The angle started to decrease above 250 K (e. g. the angle was 17 at 355 K for the double-layer structure). The results indicate that the average orientation of the water molecules in the two dimensional interlayer space depends on the layer structure and on the temperature. From the deuterium NMR spectrum at 130 K, the quadrupole coupling constant e2Qq/h = 240 kHz and the asymmetry parameter η= 0.12 were deduced. These values indicate the average hydrogen bond distance R(O H) = 2.0 Å for the D2O molecules in the 2D-interlayer space

Crystal Structures of Seven Terephthaldiamide Derivatives

2002 ◽  
Vol 57 (8) ◽  
pp. 914-921 ◽  
Author(s):  
P. G. Jones ◽  
J. Ossowski ◽  
P. Kus
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Layer Structure ◽  
Inversion Symmetry ◽  
Asymmetric Unit ◽  
X Ray ◽  
Layer Structures ◽  
Structure Determinations ◽  
Independent Molecules

N,N′-Dibutyl-terephthaldiamide (1), N,N′-dihexyl-terephthaldiamide (2), N,N′-di(tert-butyl)- terephthaldiamide (3), N,N,N′,N′-tetrabutyl-terephthaldiamide (4), 1,1′-terephthaloylbis- pyrrolidine (5), 1,1′-terephthaloyl-bis-piperidine (6), and 4,4′-terephthaloyl-bis-morpholine (7) have been synthesised and physicochemically characterised. The X-ray structure determinations reveal imposed inversion symmetry for compounds 1-6; compound 3 has two independent molecules with inversion symmetry in the asymmetric unit. Compounds 1-3 form classical hydrogen bonds of the type N-H···O=C, leading to a ribbon-like arrangement of molecules (1 and 2) or a layer structure (3). Compound 3 also displays a very short C-H···O interaction, a type of hydrogen bond that is also observed in compounds 4-7, which lack classical donors; thereby compounds 4-6 form layer structures and 7 a complex threedimensional network.

scholarly journals Mechanics for the Adhesion and Aggregation of Red Blood Cells on Chitosan

2018 ◽  
Vol 34 (5) ◽  
pp. 725-732 ◽  
Author(s):  
K. Y. Chen ◽  
T. H. Lin ◽  
C. Y. Yang ◽  
Y. W. Kuo ◽  
U. Lei
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Biomedical Applications ◽  
Adhesion Force ◽  
Layer Structure ◽  
Optical Tweezer ◽  
Wound Dressings ◽  
Zeta Potentials ◽  
Rbc Membrane ◽  
Layer Structures

AbstractHemostasis, a process which causes bleeding to stop, can be enhanced using chitosan; but the detailed mechanism is unclear. Red blood cells (RBCs) adhere to chitosan because of their opposite charges, but the adhesion force is small, 3.83 pN as measured here using an optical tweezer, such that the direct adhesion cannot be the sole cause for hemostasis. However, it was observed in this study that layer structures of aggregated RBCs were formed next to chitosan objects in both static and flowing environments, but not formed next to cotton and rayon yarns. The layer structure is the clue for the initiation of hemostatsis. Through the supporting measurements of zeta potentials of RBCs and pH's using blood-chitosan mixtures, it is proposed here that the formation of the RBC layer structure next to chitosan objects is due to the reduction of repulsive electric double layer force between RBCs, because of the association of H+ deprotonated from chitosan with COO− on RBC membrane, under the DLVO (Derjaguin-Landau-Verwey-Overbeek) theory. The results are beneficial for designing effective chitosan-based wound dressings, and also for general biomedical applications.

scholarly journals Investigations of Different Ion Intercalations on the Performance of FBG Hydrogen Sensors Based on Pt/MoO3

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4775 ◽  
Author(s):  
Gaopeng Wang ◽  
Shiwen Yang ◽  
Jixiang Dai ◽  
Yutang Dai ◽  
Tong Zou ◽  
...  
Keyword(s):  
Layer Structure ◽  
Hydrogen Sensor ◽  
Hydrogen Sensors ◽  
Practical Application ◽  
Crystalline Layer ◽  
Optimal Amount ◽  
Hydrogen Sensing ◽  
Sensing Material ◽  
Ionic Bonds ◽  
Ion Species

α-MoO3 has been used as a hydrogen sensing material due to its excellent properties and unique crystalline layer structure. However, the low repeatability of α-MoO3 based hydrogen sensor restricts its practical application. In this paper, the effect of intercalated ion species and the amount in α-MoO3 is experimentally investigated and discussed. It is concluded that the repeatability of the sensor depends on the radius of intercalated ions and amount of ionic bonds. The optimal ion species is Na+ and the optimal amount of precursor is 1 mmol.

scholarly journals Rotational symmetry of photonic bound states in the continuum

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Liangsheng Li ◽  
Yunzhou Li ◽  
Yong Zhu ◽  
Hongcheng Yin
Keyword(s):  
Photonic Crystal ◽  
Bound States ◽  
Layer Structure ◽  
Rotational Symmetry ◽  
Coupled Model ◽  
Numerical Data ◽  
Life Time ◽  
Layer Structures ◽  
Radiation Decay ◽  
The Continuum

Abstract The bound states in the continuum (BICs) have been investigated by simulating the optical reflectivity of a tri-layer photonic crystal slab. We found that optical BICs can occur in a class of photonic crystal systems with $$c_{1}^{z}$$ c 1 z , $$c_{2}^{z}$$ c 2 z or $$c_{4}^{z}$$ c 4 z rotational symmetries, which are constructed by three identical photonic crystal slabs. By applying the two mode coupled model, we obtain the reflectivity formula to fit the numerical data and evaluate the lifetime of radiation decay. In vicinity of BIC, the lifetime diverges as a power law form, when approaching the BIC point. The infinity life time of $$c_{1}^{z} {\text{ } - \text{ BIC}}$$ c 1 z - BIC in the tri-layer structure indicate that it is a true BIC. The $$c_{1}^{z} {\text{ } - \text{ BIC}}$$ c 1 z - BIC occurs robustly in tri-layer structures, but the resonance frequency of the BICs is dependent on the permittivity of slab, air-hole size and hole shape.

Theoretical Analysis of a Reactive Reinforcement Method for Cylindrical Explosion-Containment Vessels

2014 ◽  
Vol 137 (1) ◽  
Author(s):  
Sui Yaguang ◽  
Zhang Dezhi ◽  
Tang Shiying ◽  
Li Jie ◽  
Lin Qizhao
Keyword(s):  
Shock Wave ◽  
Theoretical Analysis ◽  
Plastic Strain ◽  
Numerical Simulations ◽  
Circumferential Strain ◽  
Theoretical Calculations ◽  
Practical Application ◽  
Related Research ◽  
Explosion Loading ◽  
Approximate Expressions

A method for cylindrical explosion-containment vessels was presented, which used symmetrical implosion loading cooperating with the vessels to control the out-explosion loading, increasing the anti-explosion ability of explosion-containment vessels. In this study, theoretical analysis was developed first and response of cylindrical vessels loaded with implosion and out-explosion was discussed. Approximate expressions for final circumferential strain were obtained. Comparison between the theoretical calculations and the numerical simulations showed that the proposed method could effectively reduce the plastic strain of cylindrical explosion-containment vessels. The theoretical analysis introduced in this study can provide reference for related research. In addition, problems such as spall and defense of shock wave need to be solved before the presented method could be carried out in practical application.

scholarly journals The Effect of Magnet-to-Coil Distance on the Performance Characteristics of EMATs

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5096
Author(s):  
Yutang Wu ◽  
Yunxin Wu
Keyword(s):  
Numerical Simulations ◽  
Conversion Efficiency ◽  
Performance Characteristics ◽  
Practical Application ◽  
Electromagnetic Acoustic Transducer ◽  
The Poor ◽  
Acoustic Transducer ◽  
Lift Off

The poor conversion efficiency and obvious lift-off effect of the electromagnetic acoustic transducer (EMAT) are commonly known to be problems for its practical application. For the purpose of enhancing the performance of EMATs, numerical simulations were performed in order to analyze the effect of various parameters. The results indicate that only the magnet-to-coil distance can effectively enhance the conversion efficiency and weaken the lift-off effect at the same time. When the magnet-to-coil distance is 2 mm, the lift-off effect will continue to be weakened as the magnet-to-coil distance increases, whereas the decrease of the lift-off effect is inconspicuous and the conversion efficiency starts to decline at this time. Therefore, to get the best performance of this specific EMAT, the suitable magnet-to-coil distance is 2 mm. The experiment effectively verifies the improvement of EMATs with a magnet-to-coil distance of 2 mm.

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