Propagation of Airy beams from right-handed material to left-handed material

Based on the ABCD matrix formalism,the propagation property of an Airy beam from right-handed material（RHM） to left-handed material（LHM） is investigated.The result shows that when the Airy beam propagates in the LHM,the intensity self-bending due to its propagation in the RHM can be compensated.In particular,if the propagation distance in the RHM is equal to that in the LHM and the refractive index of the LHM is n L =-1,the transverse intensity distribution of the Airy beam can return to its original state.

Design of Miniaturized Band-Pass Filter with Composite Right/Left-Handed Transmission Line

In this paper, a new miniaturized wide-pass-band filter at U band based on composite right/left- handed transmission line (CRLH TL) is implemented. The CRLH TL contributed to a broadband filter is a balanced structure with a small size of only 1.428 mm*0.5530 mm. The frequency characteristics are simulated and the results show that the 3 dB band width of the proposed filter is about 13.5 GHz from 45.8 GHz to 59.3 GHz. The insertion loss is quite flat through the pass-band and the return loss is relatively low.

High-Gain Array Antenna Based on Composite Right/Left-Handed Transmission Line

In this paper a metamaterial-inspired antenna with high gain and good directivity is designed. Based on the concept of composite right/left-handed transmission line (CRLH-TL), the proposed antenna is realized based on three leakage wave unit cell and a left handed circular ring slot incorporated on the surface. The maximum achievable gain at the resonant frequency of 5.6GHz is 6.933 dBi, and the return loss at 5.6 GHz can be –20 db. This proposed design has a simple structure and a compact dimension of 35 mm*40 mm*1 mm, which is suitable for particular wireless communication application such as WiFi and WLAN.

Wider frequency domain for negative refraction index in a quantized composite right–left handed transmission line

The refraction index of the quantized lossy composite right-left handed transmission line（CRLH-TL） is deduced in the thermal coherence state. The results show that the negative refraction index（herein the left-handedness） can be implemented by the electric circuit dissipative factors（i.e., the resistances R and conductances G） in a higher frequency band（1.446 GHz≤ ω ≤ 15 GHz）, and flexibly adjusted by the left-handed circuit components（Cl, Ll） and the right-handed circuit components（Cr, Lr） at a lower frequency（ω = 0.995 GHz）. The flexible adjustment for left-handedness in a wider bandwidth will be significant for the microscale circuit design of the CRLH-TL and may make the theoretical preparation for its compact applications.

（3＋1）-dimensional nonlinear propagation equation for ultrashort pulsed beam in left-handed material

In this paper a comprehensive framework for treating the nonlinear propagation of ultrashort pulse in metamaterial with dispersive dielectric susceptibility and magnetic permeability is presented. Under the slowly-evolving-wave approximation, a generalized （3＋1）-dimensional wave equation first order in the propagation coordinate and suitable for both right-handed material （I^HM） and left-handed material （LHM） is derived. By the commonly used Drude dispersive model for LHM, a （3＋1）-dimensional nonlinear Schrodinger equation describing ultrashort pulsed beam propagation in LHM is obtained, and its difference from that for conventional RHM is discussed. Particularly, the self-steeping effect of ultrashort pulse is found to be anomalous in LHM.

TM modes in asymmetric slab waveguides with left-handed material

Three-layer slab waveguide with left-handed materials （LHM） is discussed using the Maxwell＇s equations and their equations of dispersion relation for TM modes are obtained. By seeking the power of the slab waveguide, their equations of effective thickness for TM modes are obtained. Furthermore, the interrelated equations for right-handed materials （RHM） slab waveguide are introduced and their curves plotted. To find new properties for LHM slab waveguide, the equations and their curves for the LHM and RHM slab waveguide are compared respectively.

FMRI and EEG Reactions to Hand Motor Tasks in Patients with Mild Traumatic Brain Injury: Left-Hemispheric Sensitivity to Trauma

Background: Mild traumatic brain injury (mTBI) is one of the most common forms of cerebral pathology in young people and disorders involve dysfunctions in cognitive and motor spheres. We would like to examine the structural and functional alterations of the brain in patients with mTBI while performing hand movements. Methods: Twenty healthy right-handed subjects (age 25.1 ± 3.9) and 10 patients (age 27.9 ± 7.3) with mTBI without hemiparesis participated in the study using functional magnetic resonance imaging (fMRI) and electroencephalography (EEG). FMRI and EEG reactions were analysed during right- and left-hand movements. Results: It was shown that fMRI reactive changes have a larger inter-individual variability of activation during left-hand movements in comparison with right-hand ones in healthy subjects. The TBI patients demonstrated an increase of a diffuse component of fMRI reactive changes compared to healthy people. A greater number of the brain structures was involved, mainly at the subcortical level, mostly in the left hemisphere during right-hand movement. EEG study demonstrated coherence changes for the slow (delta) frequency bands in the left hemisphere, while performing both hand movements. In healthy persons, EEG coherence changes were observed in the fast (alhpa2) frequency band predominantly in contralateral hemispheres, while performing hand movements. Conclusion: So, fMRI and EEG studies revealed the most expressed pathological reactive changes in the left hemisphere and the brain cortical structures during right-hand movements in patients after mTBI. These data allowed us to propose that the younger brain structures were the most sensitive to mTBI.

A Novel Copper(II) Coordination Polymer with Figure-of-eight-shaped Channels Occupied by Flexible Monodentate and Bidentate N,N′-bipyrdyl Ligands

A copper（Ⅱ） coordination polymer, [Cu3（HOA）2（bpp）4]n （1, HnOA = 3,3＇,4,4＇- oxidiphthalic acid, bpp = 1,3-bis（4-pyridyl） propane）, has been hydrothermally synthesized. The crystal structure is of monoclinic, space group P21/c with a = 11.544（3）, b = 16.129（4）, c = 21.181 （6） A, β = 98.848（5）, V= 3897.0（2） A3, C84018N8H70Cu3, Mr = 1670.13, Z = 2, De = 1.423 g/cm^3, F（000） = 1722, μ = 0.887 mm^-1, R = 0.0878 and wR = 0.2583 for 8496 observed reflections （I 〉 2σ（I））. Single-crystal X-ray structural analysis reveals that 1 is a three-dimensional （3D） framework based on a two-dimensional （2D） mesomeric layer of alternating left- and fight-handed helical chains. The monodentate terminal and bidentate bridging bpp ligands in the same conformation are all encapsulated in the figure-of-eight-shaped channels, thus further stabilizing the whole three-dimensional framework.

Canonical Angular Momentum of Electron, Positron and the Gamma Photon

We calculate the canonical angular momentum of a free electron, positron and gamma photon. We show that for any particle with charge q the canonical angular momentum (Jc) is written as the summation of the kinetic angular momentum (Jkin) and the intrinsic quantum flux dependent terms. In terms of the z-components this can be written as . For a free electron (e-) and a positron (e+) depending on the spin orientation we find that:;;and respectively. Similarly for a gamma (γ) photon, propagating in z direction with an angular frequency ω, the canonical angular momentum is found to be: , here the (+) and (-) signs stand for the right and left hand circular helicity respectively.

Explanation of the Hidden Variables in the Electron-Positron Annihilation Process in Terms of the Quantum Entanglement and the Conservation of Flux Quantum

We show that the electron-positron annihilation process resulting with the creation of two gamma photons cannot be fully determined without the conservation of the angular momentum which has two elements, namely, the conservation of the spin angular momentum and the conservation of the quantum flux which work as the conservation of the magnetic moments as well. The conservation of the quantum flux has never been considered so far for any collision process. We show that the missing conservation rule in the above process is the conservation of the total quantum flux which is the hidden variable of that process. By using the quantum entanglement together with the conservation of the quantum flux we show that the initial and the final states of this collision are fully determined. We also show that each of the gamma photons created in the end carries a quantum flux of ±Φ=±hc/e?with itself along the propagation direction. Here the (+) and (−) signs correspond to the right hand and left circular helicity, respectively.

Study on relationships of electromagnetic band gap structures and left/right handed structures

Two types of dual periodic circuits are introduced. The distributions of passbands and stopbands are generated from their dispersion relationships. Based on the study, Brillouin diagrams of three representative special cases are drawn; S parameters of these three cases are simulated by Aglient ADS; the S parameters of one of the three cases are verified by an experiment. The phase characteristics are compared with those generated from the dispersion relationship. The theoretical analysis and the experimental verification show that both types of the periodic structures can behave as electromagnetic band gap （EBG） structures, right-handed structures （RHS）, and left-handed structures （LHS）, when they operate at different frequency ranges. Thus, the possibility of a physical structure showing these three different characteristics at different frequency ranges is proven.

Miniaturized fractal-shaped branch-line coupler for dual-band applications based on composite right/left handed transmission lines

In this paper,novel dual-band (DB) branch-line couplers (BLCs) employing a composite right/left handed transmission line (CRLH TL) and fractal geometry are presented for the first time.The CRLH TL,with specified characteristic impedance and phase shift,consists of lumped elements for the left handed (LH) part and fractal-shaped microstrip lines (MLs) for the right handed (RH) part,which can be designed separately.Two designed BLCs are involved in size reduction,one using a 3/2 fractal curve of first iteration,the other constructed based on a hybrid shape of fractal and meandered lines.A miniaturized principle for CRLH TL realization is derived and an exact design method for fractal implementation is developed.For verification,an example coupler was fabricated and measured.Consistent numerical and experimental results confirmed the design concept,showing that the BLCs obtain DB behavior centered at 0.9 GHz and 1.8 GHz respectively with good in-band performance,except for slightly larger coupled insertion loss for the hybrid-shaped BLC case.In addition,the proposed fractal-and hybrid-shaped BLCs obtained a 49.7% and 64.1% size reduction respectively relative to their conventional counterparts working in the lower band.The most important contributions of this article are the demonstration of compatibility between the fractal and CRLH TL techniques and the provision of an alternative approach and a new concept for designing devices.

Harmonic suppressed bandpass filter using composite right/left handed transmission line

A wideband composite right/left handed transmission line (CRLH TL) in conjunction with its corresponding equivalent circuit model is studied based on a cascaded complementary single split ring resonator (CCSSRR).The characterization is performed by theory analysis,circuit simulation,and full-wave electromagnetic (EM) simulation.The negative refractive index (NRI) and backward wave propagation performance of the CRLH TL are demonstrated.For application,a bandpass filter (BPF) with enhanced out-of-band selectivity and harmonic suppression operating at the wireless local area network (WLAN) band is designed,fabricated,and measured by combining the CRLH TL with a complementary electric inductive-capacitive resonator (CELC).Three CELC cells with wideband stopband performance in the conductor strip and ground plane,respectively,are utilized in terms of single negative permeability.The design concept has been verified by the measurement data.

Wide-band circular polarization-keeping reflection mediated by metasurface

In this paper, we show that circular polarization-keeping reflection can be achieved using reflective metasurfaces. The underlying physical mechanism of the polarization-keeping reflection is analyzed using a reflection matrix. A wideband circular polarization-keeping reflector is demonstrated using N-shaped resonators. Both the simulation and experiment results show that the polarization-keeping reflection can be achieved with a high efficiency larger than 98% over the frequency range from 9.2 GHz to 17.7 GHz for both incident left- and right-handed circularly polarized waves. Under oblique incidence, the bandwidth increases as the incident angle varies from 0°to 80°. Moreover, the co-polarization reflection is independent of the incident azimuth angles.

Compact Multiband Patch Antenna Based on CRLH-TL Structures

A compact multiband patch antenna is designed by using HFSS in this work, which is filled with composite right/left-handed transmission line （CRLH-TL） structures. The simulated results reveal that the operating frequency becomes lower with left-handed （LH） characteristics of the CRLH-TL structures enhanced, which enable antenna physical size reduction to a large extent. The proposed antenna is fabricated on the substrate Rogers R03201 （relative permittivity of 10.2）, which has a compact size of 12 mm×12 mm × 4 mm. Moreover, this antenna exhibits monopole-like radiation pattern at one resonance frequency and patch-like radiation at the other four resonant frequencies. Therefore, the designed antenna is useful for communication systems.

Nonlinear properties of the lattice network-based nonlinear CRLH transmission lines

The nonlinear properties of lattice network-based（LNB） composite right-/left-handed transmission lines（CRLH TLs）with nonlinear capacitors are experimentally investigated.Harmonic generation,subharmonic generation,and parametric excitation are clearly observed in an unbalanced LNB CRLH TL separately.While the balanced design of the novel nonlinear TL shows that the subharmonic generation and parametric processes can be suppressed,and almost the same power level of the higher harmonics can be achieved over a wide bandwidth range,which are difficult to find in conventional CRLH TLs.

Peregrine Soliton and Akhmediev Breathers in a Chameleon Electrical Transmission Line

We analyze the particular behavior exhibited by a chaotic waves field containing Peregrine soliton and Akhmediev breathers. This behavior can be assimilated to a tree with “roots of propagation” which propagate randomly. Besides, this strange phenomenon can be called “tree structures”. So, we present the collapse of dark and bright solitons in order to build up the above mentioned chaotic waves field. The investigation is done in a particular nonlinear transmission line called chameleon nonlinear transmission line. Thus, we show that this line acts as a bandpass filter at low frequencies and the impact of distance, frequency and dimensionless capacitor are also presented. In addition, the chameleon’s behavior is due to the fact that without modifying the appearance structure, it can present alternatively purely right- or left-handed transmission line. This line is different to the composite one.

Electrodynamics—Two Versions and One Problem

Based on two versions of Maxwell’s Equations we investigate the Poynting vector, the energy transport and the dispersion relation both for right- and left-handed systems. Furthermore, it is shown that the latter systems are necessarily dispersive in contrast to the former ones. In the end we discuss a published example where the mixing of expressions of both versions of Maxwell’s Equations leads to unphysical conclusions. The presentation demonstrates for students how flexible can be the work with different versions of electrodynamics but also how carefully one has to be thereby.

Spin Forms and Spin Interactions among Higgs Bosons, between Higgs Boson and Graviton

This paper offers concrete spin matrix forms of 0h spin zero particle, and shows the existent of the spin interactions among 0h spin zero particles. It is obviously hoping to approach, on the most comprehensive level, to understand what really Higgs Boson is and what role-play Higgs Boson is acting in particle physics. As a "particle" of gravitational force, the spin interaction between 0h spin zero particle (Higgs Boson) and 2h spin particle (Graviton) is given, which maybea way that people would find Graviton in future.

腹腔镜下左右手打结缝合在子宫全切术中的应用价值探究

目的:探究腹腔镜下左右手打结缝合在子宫全切术中的应用价值。方法:选取2021年4月—2023年11月于玉林市第一人民医院拟行腹腔镜下子宫全切术的患者90例为研究对象,随机分为传统组、双极电凝组、左右手组,各30例。传统组实施腔内传统打结缝合,双极电凝组实施双极凝闭血管,左右手组实施左右手打结缝合。对比三组手术情况、疼痛评分、生活质量。结果:左右手组手术时间、切口愈合时间、住院时间短于传统组与双极电凝组,术中出血量少于传统组与双极电凝组(P<0.05);术后1、3 d,左右手组视觉模拟评分法评分低于传统组与双极电凝组(P<0.05);术后,三组各项世界卫生组织生活质量测定简表评分升高,左右手组生活质量评分均高于传统组、双极电凝组(P<0.05)。结论:在腹腔镜下行子宫全切术中,对出血点进行左右手打结缝合子宫血管后再切断,可显著减少术中出血量,缩短手术时间,减轻患者疼痛,提高生活质量。