Wide Angular Range Research Articles

Probing the properties of the 0+2 state of 4He via 4He + 4He elastic and exclusive inelastic scattering measurements

The 4He+4He inelastic scattering was experimentally investigated in an exclusive measurement at the MAGNEX facility of INFN - LNS, aiming at characterizing the 0+2 resonant state of 4He. Both the 4He+4He→4He+4He∗→4He+3H+p and 4He+4He→4He+4He∗→4He+3He+n configurations were measured together with an elastic scattering measurement in a wide angular range. In the present article, the experimental setup, the measurement and the data reduction are briefly described, pointing out the significance of an exclusive inelastic scattering measurement to suppress the background originating from other processes.

Investigating theoretical and experimental cross sections for elastic electron scattering from isoflurane.

We present a comprehensive analysis of elastic electron scattering from isoflurane in the intermediate energy range of 50-300 eV. This research is motivated by the significant impact of this molecule on global warming effects. We conducted this investigation through experimental measurements using a crossed-beam apparatus and covering a wide angular range from 25 to 125 degrees. Relative differential cross sections (DCSs) were obtained and subsequently normalized on an absolute scale by using the relative flow technique, with argon as the reference gas. These DCS values were then extrapolated and integrated to determine the experimental integral cross sections (ICSs). Additionally, we employed the independent atom model and the screening corrected additivity rule with incorporated Interference effects (IAM-SCAR+I) to calculate the theoretical differential and integral cross-sections. Remarkably, the calculated cross sections align closely with the experimental measurements across the entire energy and angular range. Furthermore, this study involved a comparison of the DCSs for isoflurane with previously published DCS values for two other volatile anesthetics, sevoflurane and halothane.

Single-Layer Wide-Angle Scanning Linear Phased Arrays Based on Multimode Microstrip Patch Elements.

This paper introduces a novel single-layer microstrip patch element designed to achieve a wide beamwidth, in order to address the growing demand for wide-angle scanning capabilities in modern phased array systems. The proposed element, comprising a slot-etched circular patch and an array of metallized holes arranged in square rings, offers a unique approach to beam shaping. By carefully adjusting parameters such as the slot structure and feeding position, our element is engineered to simultaneously excite both the TM01 and TM21 modes, a key feature that contributes to its wide beamwidth characteristics. Through the constructive interference of these modes, our element demonstrates a remarkable 3 dB beamwidth of approximately 150° in both principal planes, showcasing its potential for wide-angle scanning applications. To validate the practical performance of this proposed element, two linear phased arrays are manufactured and experimentally evaluated. The simulation results confirm the wide-angle scanning capability of the antennas in both the E-plane and H-plane. Furthermore, the experimental assessment demonstrates that these linear phased arrays can effectively generate scanning beams within a frequency range of 25 GHz to 28 GHz, covering a wide angular range from -60° to 60°, while maintaining a gain loss within 3 dB. This innovative design approach not only offers a promising solution for achieving a wide beamwidth in microstrip patch elements, but also holds significant potential for the development of cost-effective phased arrays with wide-angle scanning capabilities, making it a valuable contribution to the advancement of phased array technology.

Numerical Simulation of Metasurface Grating to Function as Polarization Modulator in Quantum Key Distribution Systems

Polarization modulation plays an important role in polarization encoding in quantum key distribution. By using polarization modulation, quantum key distribution systems become more compact and more vulnerable as one laser source is used instead of using multiple laser sources that may cause side-channel attacks. Metasurfaces with their exceptional optical properties have led to the development of versatile ultrathin optical devices. They are made up of planar arrays of resonant or nearly resonant subwavelength pieces and provide complete control over reflected and transmitted electromagnetic waves opening several possibilities for the development of innovative optical components. In this work, the Si nanowire metasurface grating polarizer is designed by COMSOL Multiphysics Software to operate in the visible region and transmit the transverse magnetic polarization of light. The same structure can be rotated by different angles, i.e., 90o, 45o, and -45o to mimic the function of polarization modulation in quantum key distribution systems. The designed structure has an extinction ratio of ~ 60000 and a wide angular tolerance range of (-20o - 20o).

A Millimeter-Wave Wideband Antenna Module With Switchable Fan-Beam Radiation for Wide Coverage of 5G IoT Applications

Millimeter wave (mm-wave) antenna modules with switchable beam radiation provide a potential solution for enabling flexible wireless links and high data rate in Internet of Things (IoT) networks. Aiming to simultaneously fulfill a wide coverage and follow the cost-effective principle of IoT devices, a novel mm-wave wideband antenna module with switchable fanbeam radiation is proposed based on an air-filled planar Cassegrain beam-former. A comprehensive design procedure combing the theoretical calculation and differential evolution (DE) algorithm is first introduced to construct the beam-former with wide-angle scanning capability. The desirable apertureshared switchable fan-beam radiation with high crossover is then obtained with the aid of a proposed two-feed-per-beam (2FPB) scheme based on a low-loss integrated switch network. A prototype of the antenna in the Ka-band is fabricated by simultaneously adopting the metallic three-dimensional (3D) printing and printed circuit board (PCB) technology. Excellent operating characteristics, including a wide bandwidth of more than 32%, twenty stable fan-shaped radiation beams scanning over a wide angular range of ±45∘ in the H-plane, a high beam crossover of about -3 dB, a gain of up to 19.6 dBi, and a radiation efficiency of greater than 80% are demonstrated experimentally. With the ability to fulfill the radio coverage within a wide conical area, the presented antenna module would be an attractive candidate for the fifth generation (5G) IoT applications.

Positioning of a Photovoltaic Device on a Real Two-Dimensional Plane in Optical Wireless Power Transmission by Means of Infrared Differential Absorption Imaging

In optical wireless power transmission (OWPT), detection and positioning of the photovoltaic device (PV) in real space is essential before power transmission. One of the candidates for the robust detection of PVs is differential absorption imaging, which has been proposed by the authors. In this method, raw images are captured using absorbable (λON) and non-absorbable (λOFF) wavelengths of the PV. Then, the PV is detected from the differential image of these. In this report, the positioning of a PV on a real two-dimensional plane was investigated by means of this differential imaging. Primarily, stereo imagery was utilized for positioning. Non-stereo positioning was also investigated, in which the azimuth angle (direction) was estimated from the position of the PV in the differential image, and ranging was performed using its apparent size. There are diffuse and non-diffuse (specular) options for the λOFF reflection of the rear surface of the PV. Positioning accuracy was measured with regard to this characteristic as well as the attitude angle. Especially for a PV with specular characteristics, even though its positioning accuracy was affected by its attitude angle, the accuracy could be improved by increasing the irradiation light power. On the other hand, direction determination was stable for a wide angular range of attitudes.

Tunable multiband THz perfect absorber due to the strong coupling of distributed Bragg reflector cavity mode and Tamm plasma polaritons modes based on MoS2 and graphene

In this work, we propose a multiband terahertz perfect absorber by combining a distributed Bragg reflector (DBR) cavity with molybdenum disulfide (MoS2) and graphene. The absorption peak comes from the strong coupling of the DBR cavity mode and the two Tamm plasma polaritons (TPPs) modes. Our numerical simulations demonstrate that the degree of coupling in this hybrid system is tunable by adjusting the structural parameters, thereby allowing for control over the position and intensity of the absorption peaks. Furthermore, utilizing the tunable Fermi energy level of graphene and controlled variation of the molybdenum disulfide carrier concentration enables active switching between absorption-free, dual-band, and triple-band absorption. Additionally, the high absorption efficiency in a wide angular range and sensitivity make this device highly versatile. The coupled harmonic oscillator model is used to explain the strong coupling phenomena of the system. This simple layered structure provides a hybrid coupling system with a controlled number of bands suitable for potential active terahertz optoelectronic devices.

Multitarget Wireless Power Transfer System Strategy Based on Metasurface-Holography Multifocal Beams

Aiming at the critical problem of wireless power transfer (WPT) for the current growing number of wireless devices, the multitarget WPT system based on metasurface-holography multifocal beams and the design methods is investigated and analyzed in this article. As the propagator in near-field synthesis, a new field calculation formula is derived based on the Friis formula between the metasurface unit (MU) and the field point, which breaks the limitation of paraxial approximation and makes metasurface holography applicable in a wide-angle, long-distance, and nonplane space. Besides the phase response of MUs, the amplitude response is also introduced, which achieves the simultaneous amplitude–phase optimization of the metasurface to improve transmission efficiency. A metasurface with holography multifocal beams is first designed and engaged in forming a planar multitarget WPT system, which has been proven to radiate the designed multifocal beam and transfer power to each focal spot uniformly and efficiently after simulated, fabricated, and measured. To verify that the proposed method can achieve a near-field synthesis of multifocal beams in nonplane space over a wide angular range, a metasurface with 23-focus beam distribution on a spherical surface with an elevation angle from <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$-$</tex-math> </inline-formula> 60 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\circ}$</tex-math> </inline-formula> to 60 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\circ}$</tex-math> </inline-formula> , omnidirectional azimuth, and 66.67 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\uplambda $</tex-math> </inline-formula> radius is designed and simulated, which shows that the simulated radiation field distribution is in good agreement with the initial preset target field. This work demonstrates a feasible high-efficiency and long-distance WPT strategy for multiple targets in wide-angle and spatial scenarios.

Suppression of Coulomb-nuclear interference in the near-barrier elastic scattering of 17Ne from 208Pb

The proton drip-line nucleus 17Ne is considered a good candidate for a Borromean two-proton halo with a 15O + p + p structure. Angular distributions of the elastic scattering and inclusive 15O production for a 136 MeV 17Ne beam incident on a 208Pb target were measured for the first time at the SPIRAL1 facility, GANIL. Use of the GLORIA detector array allowed high-resolution data over a wide angular range from 20∘ up to 95∘ in the laboratory frame to be obtained. The elastic scattering angular distribution shows similarities with those for both 6He and 20Ne at equivalent collision energies with respect to the corresponding Coulomb barriers, exhibiting the suppression of the Coulomb rainbow peak characteristic of strong coupling. Optical model and coupled channel fits suggest that this is due to a combination of coupling to low-lying quadrupole resonances and Coulomb dipole coupling to the low-lying continuum, although their relative importance depends on the relevant B(E2) values which remain to be firmly determined.

Fluorescent Waveguide Lattices for Enhanced Light Harvesting and Solar Cell Performance.

We present the properties and performance of fluorescent waveguide lattices as coatings for solar cells, designed to address the significant mismatch between the solar cell's spectral response range and the solar spectrum. Using arrays of microscale visible light optical beams transmitted through photoreactive polymer resins comprising acrylate and silicone monomers and fluorescein o,o'-dimethacrylate comonomer, we photopolymerize well-structured films with single and multiple waveguide lattices. The materials exhibited bright green-yellow fluorescence emission through down-conversion of blue-UV excitation and light redirection from the dye emission and waveguide lattice structure. This enables the films to collect a broader spectrum of light, spanning UV-vis-NIR over an exceptionally wide angular range of ±70°. When employed as encapsulant coatings on commercial silicon solar cells, the polymer waveguide lattices exhibited significant enhancements in solar cell current density. Below 400 nm, the primary mode of enhancement is through down-conversion and light redirection from the dye emission and collection by the waveguides. Above 400 nm, the primary modes of enhancement were a combination of down-conversion, wide-angle light collection, and light redirection from the dye emission and collection by the waveguides. Waveguide lattices with higher dye concentrations produced more well-defined structures better suited for current generation in encapsulated solar cells. Under standard AM 1.5 G irradiation, we observed nominal average current density increases of 0.7 and 1.87 mA/cm2 for single waveguide lattices and two intersecting lattices, respectively, across the full ±70° range and reveal optimal dye concentrations and suitable lattice structures for solar cell performance. Our findings demonstrate the significant potential of incorporating down-converting fluorescent dyes in polymer waveguide lattices for improving the current spectral and angular response of solar cell technologies toward increasing clean energy in the energy grid.

The propagation characteristics of the return-stroke electric wave in consideration of corona sheath

The propagation characteristics of the return-stroke current wave along the channel are an important issue in lightning research. The temperature, electrical conductivity and radius of lightning dart‑leader channels were calculated based on spectral diagnosis. Using them as initial parameters the dispersion equation for electric wave propagating along the return-stroke channel in a wide angular frequency range was solved numerically. The dispersion relations for the electric wave with and without considering the corona sheath effect were investigated. The results showed that both the propagation velocity and amplitude of electric wave decay along the channel, and the high frequency components decay faster. The corona sheath hastens the attenuation of the electric wave. The peak current intensity is closely related to the physical characteristics of the leader channel and determines the propagation velocity and amplitude attenuation of electric wave. Inferred from the attenuation characteristics of the wave, the variation of the current intensity along the channel is mainly determined by the different attenuation rate of the harmonic components with different frequencies during the transmission process.

Oblique incidence-insensitive metamaterial absorber using strong magnetic coupling resonance for low-frequency microwave absorption

In this work, we presented an oblique incidence-insensitive metamaterial absorber (MA) based on the strong magnetic coupling resonance using the printed circuit board process, and the spacer is produced by a typical magnetic absorber material (MAM). As for reflection loss (RL) at oblique angles, it can achieve high-efficiency absorption for both transverse-electric (TE) and transverse-magnetic (TM) polarizations with a wide angular range from 0° to 60° in the low frequency of 2.33 GHz to 3.44 GHz. In addition, the magnetic coupling mechanism of the metamaterial absorber was deeply analyzed. Comparing the results of the simulation and experiment, it displays excellent absorption performance of the proposed absorber in TE and TM modes under large oblique incidence angles.

Time and magnetic field dependent magnetic order in Ca3Co2O6 revealed by resonant x-ray scattering

The observation of time dependent magnetic order in the spin-chain compound ${\mathrm{Ca}}_{3}{\mathrm{Co}}_{2}{\mathrm{O}}_{6}$, a promising candidate for showing out-of-equilibrium magnetization behavior, has received tremendous attention for over a decade. The present study uses resonant magnetic scattering close to the cobalt K-absorption edge to probe directly the time, temperature, and magnetic field dependence of the magnetic order in a ${\mathrm{Ca}}_{3}{\mathrm{Co}}_{2}{\mathrm{O}}_{6}$ single crystal. Energy dependences of the magnetic signal and their simulation suggest that the resonant x-ray scattering (RXS) signal at the pre-edge contains contributions only from quadrupole (E2E2) and dipolar-quadrupolar (E1E2) transition processes. Interestingly, the flat intensity variation as a function of azimuthal angle over a wide angular range cannot be explained by considering the ordering of magnetic dipole moments alone. The observed magnetic order below the N\'eel temperature ${T}_{N}$ in the present RXS study differs significantly from the reported neutron diffraction results, indicating possible contributions from high-order moments in addition to the magnetic dipole moment.

Brewster-coupling-based thin film filter design for wide-angle high-efficiency phosphor emission.

In this paper, we propose a bandpass filter design method for laser activated remote phosphor (LARP) usage. This design uses the Brewster angle as the passband instead of a wavelength passband. Two advantages are found with this design. First, the transmittance at the Brewster angle is naturally 100%, which is optimal. Second, the stop band reflectance with a wide angular range is better compared to the dichroic filter in a LED-phosphor model. We design two optical thin film filter samples to enhance the extraction efficiency of YAG:Ce phosphor with the same design criteria, objective function, and optimization algorithm. With 50-layer designing, the optical losses for LARP are 23.7% and for LED-phosphor are 26.0%.

Hidden chamber discovery in the underground Hellenistic necropolis of Neapolis by muography

We report in this paper the muography of an archaeological site located in the highly populated “Sanità” district in the center of Naples, ten meters below the current street level. Several detectors capable of detecting muons - high energy charged particles produced by cosmic rays in the upper layers of atmosphere - were installed underground at the depth of 18 m, to measure the muon flux over several weeks. By measuring the differential flux with our detectors in a wide angular range, we have produced a radiographic image of the upper layers. Despite the architectural complexity of the site, we have clearly observed the known structures as well as a few unknown ones. One of the observed new structures is compatible with the existence of a hidden, currently inaccessible, burial chamber.

Zero-point motion of liquid and solid hydrogen

We present an inelastic neutron scattering study of liquid and solid hydrogen carried out using the wide Angular Range Chopper Spectrometer at Oak Ridge National Laboratory. From the observed dynamic structure factor, we obtained empirical estimates of the molecular mean-squared displacement and average translational kinetic energy. We find that the former quantity increases with temperature, indicating that a combination of thermal and quantum effects is important near the liquid-solid phase transition, contrary to previous measurements. We also find that the kinetic energy drops dramatically on melting of the crystals, a consequence of the large increase in molar volume together with the Heisenberg indeterminacy principle. Our results are compared with quantum Monte Carlo simulations based on different model potentials. In general, there is good agreement between our findings and theoretical predictions based on the Silvera-Goldman and Buck potentials.

Analysis of elastic scattering of 6Li by 90Zr near Coulomb barrier

We use a phenomenological optical potential constructed in consideration of a versatile potential developed by Joseph N. Ginocchio. The optical potential uses less number of energy-dependent parameters to analyse nuclear scattering data. We study the ratios of elastic to Rutherford differential scattering cross sections of the system 6Li + 90Zr at various energies, namely, 10.19, 11.11, 12.07, 13.95, 15.84, 17.71, 19.60, 23.36, 28.05 and 31.87 MeV in the centre-of-mass system. The study of angular distributions is performed in a wide angular range. Our theoretical calculations explain the experimental results and follow breakup threshold anomaly phenomenon near the Coulomb barrier. We discuss the variation of reflection function |S l | with ‘l’ for each contributing partial wave and calculate reaction cross section for the system against the projectile energy 31.87 MeV with permissible error.

Integrated innovative solar lighting system for optimization of daylight utilization for public library in Alexandria, Egypt

Lighting has evolved over recent decades from an engineering perspective, in which ensuring safety and performance both indoors and outdoors has become a key discipline, engaged in a wide range of areas and having a profound impact on our daily lives. In this paper, a case study of a modern public library building will be addressed, with the main purpose of discussing energy efficiency related to light. Three parallel routes will be demonstrated to improve energy efficiency. The first is the integration of solar systems (PV) and the replacement of artificial lighting systems. The second is a change of building materials, internally and externally, to nanomaterials, and the third is through including an innovative anidolic lighting system, designed and applied in order to enhance the amount of daylight inside the library in a controlled manner. The inclusion of a vertical lighting system allows the optimization of solar energy resources, preserving the library’s style in a simple way. The system includes a collector light system, compounded by a truncated and double compound parabolic collector (PCPC) to capture natural light from outside over a wide angular range (180°) without a tracking system, preserving the building design and saving on costs and maintenance. These parallel routes, based on solar energy and lighting, can make a positive impact with minimum changes in the Alexandria library, providing environmental improvement and protecting buildings and human health in order to achieve a more sustainable example of architecture.

A Low-Scattering Vivaldi Antenna Array With Slits on Nonradiating Edges

To reduce in-band scattering over a large angular range, this communication presents a low-scattering Vivaldi antenna array with cutting slits on the nonradiating edges of each antenna element. Over-concentrated overlap between structural modal and antenna modal scattering currents motivates the novel slit design over the nonradiating edges. These slits separate the structural modal and antenna modal scattering currents in the largest extent. The structural modal scattering is then suppressed through a cavity like structure in the nonradiating portion, while the antenna modal scattering currents keep unchanged as they are crucial for the radiation performance. The design features with a simple structure, while effectively reduces the in-band radar cross Section (RCS) in a wide angular range of ±70° and achieves ±60° scanning in the E-/H-planes over the entire X-band. Prototypes for the proposed <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8\times $ </tex-math></inline-formula> 8 Vivaldi antenna array and a reference conventional Vivaldi antenna array are fabricated, assembled, and measured. Both measured and simulated results demonstrate the effectiveness of the low-scattering Vivaldi antenna array design.

Low-frequency broadband multilayer microwave metamaterial absorber based on resistive frequency selective surfaces.

Herein, a low-frequency broadband multilayer metamaterial absorber (MMA) based on resistive frequency selective surfaces (RFSSs) is proposed, which consists of a three-layer RFSS, three-layer polymethacrylimide (PMI) foam substrates, and a copper film. The proposed absorber has the advantages of ultra-broadband absorption with absorptivity more than 90% ranging from 1.91 to 20.78GHz, which covers the entire S, C, X, and Ku bands with the thickness of 0.102λ L (where λ L corresponds to the wavelength of the lowest operating frequency). The absorption performance can keep good stability in a wide angular range for both TE and TM modes. Moreover, a prototype of the proposed MMA is fabricated and experimentally measured to demonstrate its excellent performance. The experimental results show excellent consistency with numerical simulations.