Modern Physics Letters B

Predicting properties of materials and phase transformation using theoretical and computational multi-scale methods involving artificial intelligence and machine learning (ML) is important and highly rewarding. We review the relevant methods and mention a few applications and examples. We demonstrate that theoretical guidance narrows the search space and accelerates materials discovery.

This paper presents a low $1/f$ noise CMOS single-ended output instrumentation amplifier (IA) for tunneling magnetic resistance (TMR) sensors. For high DC gain and linearity, the amplifier employs three-stage current-feedback topology. For high CMRR and PSRR, the first two stages employ fully differential input. To maintain stability and lower the power dissipation, the amplifier employs trans-conductance with capacitance feedback compensation (TCFC) topology. The amplifier employs chopping technology and continuous-time AC-coupled ripple reduction loop to reduce $1/f$ noise and chopping ripple. The whole chip is fabricated using 0.35 $\mu$m CMOS-BCD technology and the total area is 1 mm². Test result shows an input-referred noise power spectral density (PSD) of 14 nV/$\sqrt{\mathrm{\text{Hz}}}$ is achieved with 1 Hz $1/f$ corner. The bandwidth is larger than 50 kHz $(65\times \mathrm{\text{magnification}})$ with 20 pF load capacitor. The total current is 300 $\mu$A at 5 V supply.

This work is devoted to study the extraction dearomatization of the kerosene fraction using ionic liquids synthesized on the basis of formic acid and morpholine, as well as acetic acid and diethylamine as a selective solvent. The influence of various factors on the selective purification process has been investigated and the conditions for dearomatization of kerosene have been determined. The group hydrocarbon composition of the dearomatized kerosene raffinate samples by ion-liquid extraction was determined by IR and UV spectral analysis.

We use numerical and experimental methods to investigate the low frequency sound insulation characteristic of designed thin acoustic black hole (ABH). The numerical results show that the sound energy focusing effect plays a leading role in low frequency sound insulation of designed ABH, and the reflection at the edge of ABH is the main reason of sound insulation in medium and high frequencies. Experimental results display that the Sound Transmission Loss (STL) of the designed ABH is higher than 30 dB below 700 Hz, which shows that the isolated acoustic waves are more than 95%. The low frequency sound insulation performance of proposed ABHs is much better than the traditional acoustic materials, which has great potential applications for low frequency sound insulation.

Modern optical technology has greatly facilitated the implementation of free-space quantum key distribution. However, the influence of atmosphere on the beam propagation is always unpredictable and could impair the system performance to some extent. It is necessary to develop an efficient model that could describe the beam propagation and receiving. In this paper, a single-photon receiving efficiency model is proposed incorporating the single-photon acquisition probability and channel transmittance based on the Gaussian beam propagation. We also present simulation and experiment of beam-spot size widening through a 0.5 km free-space channel to verify the proposed model. The results show that with the increase of turbulence strengths, the single-photon acquisition probability will degrade more sharply. The single-photon receiving efficiency will decrease with the increment of the ratio between beam centroid deflection and the receiving aperture radius $r/a$.

In this paper, the Heisenberg ferromagnetic spin chain equation, which is a model with different magnetic interactions in the classical and semiclassical limits, is investigated using the generalized exponential rational function method. The reduction of the governing equation to a simpler ordinary differential equation by wave transformation is the first step of the procedure. A plurality of the exact solution is obtained by using the relevant method. Physical interpretations of some obtained solutions are also included. Particularly, upon choosing appropriate parameters, various plots are depicted. We achieve also a numerical solution corresponding to the initial value problem by the Elzaki–Adomian decomposition method and give comparative results in a table. Moreover, by using Maple, some graphical simulations are done to see the behavior of these solutions with choosing the suitable parameters.

The new types of nonlinear localized state of generalized order parameter in the three-layered structure of band antiferromagnets with congruent sections of the Fermi surface are obtained. The nonlinear effects inside the narrow plane defects between the layers representing the local magnetization in the direction of polarization of the spin density wave are described by the nonlinear source function. The variation of the Ginsburg–Landau functional near the Lifshitz point leads to nonlinear Schrödinger equation (NSE) with cubic nonlinear terms and self-consistent nonlinear potential modeling the plane defects. The dispersion equations of two type stationary nonlinear localized states are derived. The solutions of dispersion equations in explicit analytical form in dependence on characteristics of plane defects and the distance between them are found and analyzed. The localized states of order parameter existing only near the plane defects with nonlinear response are obtained.

Owing to the growing interest of bioconvection flow of nanomaterials, many investigations on this topic have been performed, especially in this decade. The bioconvection flow of nanofluid includes some novel significance in era of biotechnology and bio-engineering like bio-fuels, microbial enhanced oil recovery, enzymes, pharmaceutical applications, petroleum engineering, etc. The current analysis aims to explore the various thermal properties of Sutterby nanofluid over rotating and stretchable disks with external consequences of variable thermal conductivity, heat absorption/generation consequences, activation energy and thermal radiation. The considered flow problem is changed into dimensionless form with convenient variables. The numerical structure for the obtained non-dimensional equations is numerically accessed with built-in shooting technique. The consequences of various physical parameters are observed for enhancement of velocity, temperature, concentration and motile microorganism. It is noted that both axial and tangential velocity components decrease with Reynolds number and buoyancy ratio parameter. The nanofluid concentration improves with activation energy and concentration Biot number. Moreover, an improved microorganisms profile is noticed with microorganism Biot number and bioconvection Rayleigh number.

The effect of shape, material and shell thickness on electric field distribution of both Ag@CuO and Ag@ZnO core–shell dimer is investigated. First, three core–shell structures, including plane@circle, triangle@circle and quadrilateral@circle are designed. The field enhancement advantages of the quadrilateral@circle structures are summarized by analyzing the electric field distribution diagrams. Then the influence of materials on the field enhancement effect of core–shell dimer is discussed. The results show that Ag@CuO structure has better stability, while Ag@ZnO structure have larger electric field enhancement. Finally, the shell thickness is changed from 0.1 nm to 1.5 nm. We found that the X-component electric field of both the Ag@ZnO and Ag@CuO core–shell dimer structure is decreased with the increase in the shell thickness. Also, the X-component electric field of Ag@ZnO core–shell dimer is about five times than that of the Ag@CuO. The increase of electric field indicated that Ag@ZnO core–shell dimer has strong local surface plasma resonance characteristics.

In this research, we will show that as the flow rates of CF₄ $({\mathrm{\text{CF}}}_4/(\mathrm{\text{Ar}}+{\mathrm{\text{CF}}}_4))$ are different, the optical, crystal, and electrical properties of FZO films have large variations. At first, ZnO target is prepared by ourselves, the radio frequency (RF) magnetron sputtering is used as a method for the deposition of FZO films, and different flow rates of CF₄ gas is introduced into the chamber during the deposition process. Next, we use the EagleXG glass as the substrates to deposit FZO films and we control the deposition time to make the thicknesses of deposited FZO films at about 330 nm. The flow rate of CF₄ gas is controlled using ${\mathrm{\text{CF}}}_4/(\mathrm{\text{Ar}}+{\mathrm{\text{CF}}}_4)$ mixing atmosphere and it is changed from 0% to 0.5%. After FZO films are deposited, their crystalline phase is identified using XRD, surface morphology and thickness that are observed using SEM, optical property (which is further used to measure the optical energy gap) are measured using an n&k analyzer, and electrical properties are measured using Hall equipment. A comparative study on the residual fluorine is also analyzed using FESEM equipped with energy dispersive X-ray spectroscopy (EDS) analysis.

The existence of pressure pulsations greatly increases the vibration and noise of pumps and harms their service life. In this paper, a casing treatment was employed to explore its impact on the pressure pulsations. A U-tube type groove was created at the inlet end-wall of a centrifugal pump and front cover of the impeller to connect the impeller with the inlet pipe by passing impeller leading edge. An unsteady numerical investigation was launched of the pump with and without this casing treatment, to study its influence on the pressure pulsations inside the pump and the mechanisms behind. The numerical results of the pump without casing treatment was first compared with the test performance of the pump to validate the numerical method, and gave excellent agreements with the test results. The CFD results also showed that the casing treatment increases the head coefficient and efficiency of the pump. Pressure pulsations at a reduced mass flow condition were studied by monitoring unsteady pressure signals generated by the CFD at various locations inside the pump. A Fast Fourier transform (FFT) was performed on the signals. The pump employs a double tongues volute with each tongue covering 180${}^{\circ }$ circumference. However, the two tongues are not identical with regard to the discharge of the pump. These geometric features of the volute and the pump’s operating condition generate several pressure pulsations in the frequencies of $f_n$, $2f_n$, $3f_n$ in the original pump. Due to the circumferential unifying capability of the casing treatment and its improvement to the impeller flow, these pulsations at impeller inlet are weakened or disappear when the U-tube is present. The pressure pulsation inside the impeller is less affected by the treatment. The $3f_n$ pulsation at volute tongues also decreases or disappears for the same reasons, but $f_n$ pulsation increases slightly and this is due to the improved pressure recovery in the volute by the treatment which increases the pressure difference across one of the volute tongues. The unsteady radial force of the impeller exerting on journal bearings becomes more uniform and smaller when the casing treatment is employed.

In this paper, we focus on investigating a nonlinear Schrödinger-type equation with nonzero boundary at infinity. An appropriate two-sheeted Riemann surface is introduced to map the original spectral parameter $k$ into a single-valued parameter $z$. Starting from the Lax pair of the Schrödinger-type equation, we derive its Jost solutions with nonzero boundary conditions, and further analyze the asymptotic behaviors, analyticity, the symmetries of the Jost solutions and the corresponding spectral matrix. An associated matrix Riemann–Hilbert (RH) problem associated with the problem of nonzero boundary conditions is subsequently presented, and a formulae of $N$-soliton solutions for the Schrödinger-type equation by solving the matrix RH problem. As an application of the $N$-soliton formulae, we present two kinds of one-soliton solutions and three kinds of two-soliton solutions according to different distributions of spectral parameters, and dynamical features of those solutions are also further analyzed.

Hydrophobic antireflective coating is fabricated by physical vapor deposition. The optical, contact angle and laser damage resistance properties are investigated, respectively. The transmittance of the antireflective coating with hydrophobic layer is 99.58% at 1064 nm with normal incidence. The contact angle with water is 115.6${}^{\circ }$. The laser damage threshold of the zero probability is 22 J/cm² at 1064 nm with the 12 ns pulse width. This new hydrophobic antireflective coating can be applied in the areas of astronomical optics, laser medical equipment and solar energy, etc.

In this paper, a wideband receiver front-end including the flexible reconfigurable main and auxiliary paths is proposed. Therein, the main path has the low-noise advantage thanks to the low-noise transconductance amplifier (LNTA) preceding the mixer and baseband. Meanwhile, by utilizing a mixer-first structure, the auxiliary path renders a high in-band and out-of-band linearity. Furthermore, an inductor resonance structure is also designed to mitigate the baseband noise crosstalk issue which is disclosed by a charging/discharging mechanism via the tail capacitance of passive mixers. Both of the receiving paths have shared a common baseband circuit while loading a commonly-shared 25% duty-cycle LO source generator. Simulation results by a 180 nm CMOS have demonstrated that the main path provides a low noise figure (NF) of 2.7 dB, while the auxiliary path obtains the in-band and out-of-band IIP3 of 9.2 and 21 dBm under typical LO excitation frequency of $f_{\mathrm{\text{LO}}}=1.25$ GHz. The power consumption of the main path of the dual-path front-end is 57 mW and that of the auxiliary path is 26 mW under a supply voltage of 1.8 V.

In this work, the crystal structures and phase transitions of compounds with perovskite structure were investigated. The classification of structural phase transitions in perovskites was carried out, the most common crystal structures and structural phase transitions were shown. A mathematical model was constructed, a theorem was given and proved for the probability of a possible transition. The formulas $E({\tau }_1)=(\frac{{(\lambda \beta )}^2}{8}+\frac{\lambda \beta }{2}+1)E({\xi }_1)$ and $D({\tau }_1)=(\frac{{(\lambda \beta )}^4}{96}+\frac{{(\lambda \beta )}^3}{12}-\frac{3{(\lambda \beta )}^2}{8}-\frac{\lambda \beta }{2}){(E{\xi }_1)}^2+(\frac{{(\lambda \beta )}^2}{8}+\frac{\lambda \beta }{2}+1)D({\xi }_1)$ are given for the mathematical expectation and variance of random variable ${\tau }_1$, which is the moment when the stochastic process $X(t)$ deviation from the boundary [0, $\beta$] interval for the first time. According to the mathematical model, one of the trajectories of random processes corresponding to the phase transitions that occur in perovskites is constructed.

Hydroxyapatite scaffold is a type of bio-ceramic. Its cellular design has similarities with the morphologies in nature. Therefore, it is very important to control the structure, especially the porosity, as one of the main features for bio-ceramics applications. According to some literature, freeze casting can form the shape of dendrites and remain a foam structure after ice sublimation. Ice nucleation became more heterogeneous with the aid of printing materials during freeze casting. This procedure can even improve the issue of crack formation. In this paper, we studied the mechanical properties of hydroxyapatite scaffold. We also analyzed the porosity by fractal nature characterization, and successfully reconstructed pore shape, which is important for predicting ceramic morphology. We applied SEM analysis on bio-ceramic samples, at four different magnifications for the same pore structure. This is important for fractal analysis and pores reconstruction. We calculated the fractal dimensions based on measurements. In this way, we completed the fractal characterization of porosity and confirmed possibilities for successful porous shapes reconstruction. In this paper, we confirmed, for the first time, that fractal nature can be successfully applied in the area of porous bio-ceramics.