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It is well established that calcium phosphate can be a self-activated photoluminescent agent via lattice water removal-induced intrinsic defects, whose luminescence intensity can be further enhanced in terms of the amorphous state. Inspired by these facts, self-activated photoluminescent amorphous magnesium phosphate (MgP) was synthesized via microwave irradiation and thermal processing, along with calcium magnesium phosphate (CaMgP) and calcium phosphate (CaP) for comparisons. The relevant fluorescence imaging and transient steady-state fluorescence spectrometer tests revealed that the fluorescence performance of the as-formed particles increased in the order of CaP, CaMgP, and MgP. This phenomenon was attributed to the difference in structural water loss among these particles during thermal processing, in which the three tested materials experienced weight losses of 10%, 19%, and 25% when heated to $400^{\circ }$C. Despite this, when amorphous MgP was heated up to 200, 300, and $400^{\circ }$C, its photoluminescence emission intensity also increased. The impact of the pH of the precursor solution was also studied, paving the way for further improving MgP’s photoluminescence properties.

The microwave heating synthesis of (phthalocyaninato)bis(chloro)silicon(IV) prepared from diiminoisoindolene and silicon tetrachloride in quinoline has been shown to be rapid (5 min reaction time compared to 30 min with thermal heating) and results in a high yield (91% compared to 71% using thermal heating). A modified microwave ashing furnace was used to heat the reaction mixture. The high yield has led to a reduction in the purification time to 1 h (compared to 4 h or more using conventional heating).

Silicon carbide (SiC) offers significant advantages for microwave high power devises due to its unique electrical and thermal properties. This review presents a summary of the current position in the development of silicon carbide diodes operating at microwave frequencies: varactors, Schottky barrier mixer diodes, p-i-n and IMPATT diodes. Simplified theory of device operation is given for each kind of microwave diodes to derive the figures of merit, to estimate the potential silicon carbide performance for fabrication of these diodes and to compare SiC with conventional semiconductors. These analyses are followed by description of diode design, fabrication and measured characteristics.

By mixing two infrared radiations near 1 μm in a 47-mm-long GaSe crystal, we efficiently generated a monochromatic radiation which has frequency tunability from 4.51 THz down to 53 GHz. The highest peak power produced by us is 389 W at 203 μm (1.48 THz), which corresponds to the photon conversion efficiency of 19% (the power conversion efficiency of 0.098%).

Giant-amplitude oscillations in dc magnetoresistance of a high-mobility two-dimensional electron system can be induced by millimeterwave irradiations, leading to zero-resistance states at the oscillation minima. Following a brief overview of the now well-known phenomenon, this paper reports on aspects of more recent experiments on the subject. These are: new zero-resistance states associated with multi-photon processes; suppression of Shubnikov-de Haas oscillations by high-frequency microwaves; and microwave photoconductivity of a high-mobility two-dimensional hole system.

We have studied the influence of the methane gas (CH₄) pressure on the surface morphology, composition, structural and electrical properties of nitrogenated amorphous carbon (a-C:N) films grown by surface wave microwave plasma chemical vapor deposition (SWMP-CVD) using Scanning electron microscopy (SEM), Atomic force microscopy (AFM), Auger electron spectroscopy (AES), X-rays photoelectron spectroscopy (XPS), UV-visible spectroscopy and 4-point probe resistance measurement. We have succeeded in growing a-C:N films using a novel method of SWMP-CVD at room temperature and found that the surface morphology, bonding, optical and electrical properties of a-C:N films are strongly dependent on the CH₄ gas sources and the a-C:N films grown at higher CH₄ gas pressure have relatively high electrical conductivity.

Tuned narrow-band-sensing of microwave and terahertz radiation can be realized by subjecting an irradiated two-dimensional electron system to both a static and a time varying magnetic field, and detecting at the harmonics of the modulation.

Further and more detailed experimental work demonstrates an anomalous transfer of modulation between two microwave beams in the near-field and confirms the results already obtained. The behavior of the measured signal versus the attenuation of each beam intensity suggests a model based on the existence of hybrid terms containing the product of both the relative field amplitudes. In addition, the undulating shape of the signal suggests the presence of stochastic processes.

Expressions for the effective permeability tensor of two-component partially magnetized ferrite-like metamaterials are obtained in the microwave frequency range. The formulas are based on the theory of partially saturated conventional ferrites and the effective medium theory (EMT) of metamaterials presented in a form of an infinite host dielectric medium with periodically embedded ferric cylindrical and spherical inclusions partially magnetized with an external bias DC magnetic field. The low-field losses absence conditions are obtained for the metamaterials under the assumption of a low phenomenological loss term and losses are estimated.

In this paper, firstly we have synthesized ZnO nanowires using zinc acetate, ethanol and ammonium hydroxide by a thermo-chemical method and then ZnO nanorods (NRs) have been prepared by microwave irradiation (MI) of an initial solution containing ZnO nanowires. X-ray diffraction (XRD) analysis showed the rare zinc-blende phase which grows on the surface of NRs and its crystallite size increases with the increase of microwave power. The average length and width of rods were observed several hundreds of nanometer and 80nm, respectively, from scanning electron microscope (SEM) analysis. Ultraviolet-visible (UV-vis) absorption spectroscopy indicates that a band tail forms due to MI, which has roughly 2eV energy gap. Photoluminescence (PL) spectroscopy indicated a blue emission and a white emission for ZnO nanowires and NRs, respectively. MI quenches the UV emission from ZnO NRs and enhances the surface defects’ emission. The resultant visible PL of the samples increases with the increase of microwave power that shows the growth of zinc-blende phase which has crucial effect on the defect density of NRs.

In this work, CdSe QDs were synthesized using a microwave assisted method and chemical reaction between NaHSe, CdSO₄ at the presence of TGA as capping molecule. Thereafter without CdSe extraction, CdS shell was grown subsequently around CdSe cores by a reaction based on the heat sensitivity of Na₂S₂O₃ dissociation. Synthesized QDs were characterized by means of X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), UV–Vis and photoluminescence (PL) spectroscopy. All of these analyzes confirmed formation of CdSe QDs and successfully growth of CdS shell on surface of CdSe to forming CdSe/CdS core-shell structure.

Stability of Ag₂S@ZnS QDs in water is a crucial concern for their application in biology. In this work, both physical sustainability and emission stability of Ag₂S QDs were enhanced using parameter optimization of a pulsed microwave irradiation (MI) method up to 105 days after their preparation. UV–Vis and photoluminescence spectroscopies depicted an absorption and emission about 817 nm and 878 nm, respectively. X-ray diffraction (XRD) analysis showed a growth of Ag₂S acanthite phase. Transmission Electron Microscopy (TEM) images revealed a clear formation of Ag₂S@ZnS core–shell structure.

Further experimental investigations in the microwave field emerging from a composite pupil are reported in order to determine the nature of the wave propagation. The experiments consisted of delay-time measurements as a function of the distance of the detector from the pupil under test, as well as of the phase variation of a radio-frequency signal at 35 MHz that modulated the same microwave carrier at 9.33 GHz. In addition, measurements employing an admittance comparator were made in order to determine the character of the propagation impedance. All results obtained confirmed superluminal behavior in the near field, up to a distance of about 40 cm. These results were then interpreted within the framework of a stochastic model.

New results are obtained with a modified experimental setup, in order to reduce the residual detected signal when the unmodulated beam is strongly attenuated. In the light of these results, the transfer of modulation, from the modulated beam to the unmodulated one, can be attributed to a photon–photon scattering mechanism, operating in the crossing area of the two beams. Even the stochastic character of the process becomes more plausible.

Due to the ultra-high carrier mobility and ultralow resistivity of Graphene channel, a Graphene field effect transistor (GFET) is an interesting candidate for future RF and microwave electronics. In this paper, the introduction and review of existing compact circuit-level model of GFETs are presented. A compact GFET model based on drift-diffusion transport theory is then implemented in Verilog-A for RF/microwave circuit analysis. Finally, the GFET model is used to design a GFET-based distributed amplifier (DA) using advanced design system (ADS) tools. The simulation results demonstrate a gain of 8dB, an input/output return loss less than $-$10dB, $-$3dB bandwidth from DC up to 5GHz and a dissipation of about 60.45mW for a 1.5V power supply. The main performance characteristics of the distributed amplifier are compared with 0.18$\mu$m CMOS technology.

Recent cosmic microwave background (CMB) data in temperature and polarization have reached high precision in estimating all the parameters that describe the current so-called standard cosmological model. Recent results about the integrated Sachs–Wolfe (ISW) effect from CMB anisotropies, galaxy surveys, and their cross-correlations are presented. Looking at fine signatures in the CMB, such as the lack of power at low multipoles, the primordial power spectrum (PPS) and the bounds on non-Gaussianities, complemented by galaxy surveys, we discuss inflationary physics and the generation of primordial perturbations in the early universe. Three important topics in particle physics, the bounds on neutrinos masses and parameters, on thermal axion mass and on the neutron lifetime derived from cosmological data are reviewed, with attention to the comparison with laboratory experiment results. Recent results from cosmic polarization rotation (CPR) analyses aimed at testing the Einstein equivalence principle (EEP) are presented. Finally, we discuss the perspectives of next radio facilities for the improvement of the analysis of future CMB spectral distortion experiments.

In recent years, significant progress has been made in building new galaxy clusters samples, at low and high redshifts, from wide-area surveys, particularly exploiting the Sunyaev–Zel’dovich (SZ) effect. A large effort is underway to identify and characterize these new systems with optical/NIR and X-ray facilities, thus opening new avenues to constraint cosmological models using structure growth and geometrical tests. A census of galaxy clusters sets constraints on reionization mechanisms and epochs, which need to be reconciled with recent limits on the reionization optical depth from cosmic microwave background (CMB) experiments. Future advances in SZ effect measurements will include the possibility to (unambiguously) measure directly the kinematic SZ effect, to build an even larger catalogue of galaxy clusters able to study the high redshift universe, and to make (spatially-)resolved galaxy cluster maps with even spectral capability to (spectrally-)resolve the relativistic corrections of the SZ effect.

The rotation of galactic halos is a particularly difficult subject to be dealt with. It has been shown that CMB data toward nearby galaxies can be used to probe the galactic halo rotation and can be ascribed to cold molecular clouds populating the halos. We present some methods to study the physical properties and distribution of such molecular gas clouds in the M31 galaxy halo.

Cosmological and astrophysical surveys in various wavebands, in particular from the radio to the far-infrared, offer a unique view of the universe’s properties and the formation and evolution of its structures. After a preamble on the so-called tension problem, which occurs when different types of data are used to determine cosmological parameters, we discuss the role of fast radio bursts in cosmology, in particular for the missing baryon problem, and the perspectives from the analysis of the 21 cm redshifted line from neutral hydrogen. We then describe the Planck Legacy Archive, its wealth of scientific information and next developments, and the promising perspectives expected from higher resolution observations, in particular for the analysis of the thermal Sunyaev–Zel’dovich effect. Three cosmological results of the Planck mission are presented next: the implications of the map of Comptonization fluctuations, the dipole analysis from cross-correlating cosmic microwave background anisotropy and Comptonization fluctuation maps, and the constraints on the primordial tensor-to-scalar perturbation ratio. Finally, we discuss some future perspectives and alternative scenarios in cosmology, such as the study of the Lorentz invariance violation with the cosmic microwave background polarization, the introduction of new gravitational degrees of freedom to solve the dark matter problem, and the exploitation of the magnification bias with high-redshift sub-millimeter galaxies to constrain cosmological parameters.

Studying the rough structure characteristics of rock fracture surfaces under microwave irradiation is of a great significance for understanding the rock-breaking mechanism. Therefore, this work takes fracture surface as the research object under three failure modes: microwave irradiation, uniaxial loading and microwave-uniaxial loading. The undulation and roughness are used to describe the morphological characteristics of the fractured surface. Research shows that the fracture surface under microwave irradiation is the smoothest, which exhibits undulation and rough fractal dimension in the range of 1–7mm and 2.0005–2.0657, respectively. The fractal anisotropy of the fracture surface is the most obvious under microwave irradiation. The roughness along the fracture surface is about 1.02 times that is perpendicular to the fracture direction. In the perspective of size effect characteristics, the roughness of the fracture surface under microwave irradiation shows a positive correlation with the selected size. The results provide a certain basis for interpreting the mechanism of microwave rock breaking.