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The application scopes of two different reductive perturbation methods to derive the Korteweg–de Vries (KdV) equation and coupled KdV (CKdV) equation in two-temperature-ion dusty plasma are given by using the particle-in-cell (PIC) numerical method in the present paper. It suggests that the reductive perturbation method (RPM) is valid if the amplitude of the CKdV solitary wave is small enough. However, for the KdV solitary wave, RPM is valid not only if the amplitude of the KdV solitary wave is small enough, but also if the nonlinear coefficient of the KdV equation is not tending to zero.

The reflection and transmission of an incident solitary wave with an arbitrary propagation direction due to an interface are investigated in the present paper. It is found that the propagation direction of the transmitted solitary wave depends on not only the propagation direction of the incident solitary wave, but also on the system parameters such as the masses, the number densities of dust particles in two different regions. Dependence of the transmission angle on the plasma parameters and incident angle are given analytically. Moreover, the number and amplitude of transmitted solitary waves and reflected solitary waves are also given when there is only one exact incident solitary wave. Our result has potential application, for example, we can devise an appropriate experiment to measure the differences of the masses and number densities of dust particles between two different regions by using our present results. Furthermore, we can also measure the electric charge of a dust particle by devising an appropriate experiment by using our results.

A bubble equation of motion close to the solid plane is obtained by using the perturbation method. This bubble equation can explain the phenomena of the reentrant microjet penetrating the bubble produced by the external disturbances if the distance between the bubble center to the solid boundary is small enough as well as the external pressure is large enough. Furthermore, two critical points are found. One critical point is the distance between the bubble center to the solid boundary. The other is external pressure. The critical boundary at which the reentrant microjet can just be produced is given. The critical boundary depends on both the distance between the bubble center to the solid boundary and the ratio of external pressure to the initial pressure of the liquid.

Charge transfer (CT) crystals of an electron donor and an acceptor have electronic properties that are different from the two pure components. Despite the great potential of such CT crystals have f...

It is well known that the ponderomotive force of a relatively high-frequency magnetosonic wave (HMSW) can excite the low-frequency magnetosonic wave (LMSW). By using the coupled system of dynamical equations of LMSW in the presence of a ponderomotive force of HMSW (pump wave), we have studied the modulational instability of the coupled waves between the HMSW and the LMSW. It is found that there are instabilities for the coupled waves between the HMSW and the LMSW. It is also found that the growth rate depends on several system parameters, such as the frequency of HMSW, the perturbation wave vector, and the background magnetic field.

Different kinds of waves and instabilities in the F-region of the ionosphere excited by the relative streaming of the dust beam to the background plasma are studied in the present paper. The dispersion relations of different waves are obtained on different time scales. It is found from our numerical results that there are both a stable upper hybrid wave on the electron vibration time scale and a stable dust ion cyclotron wave on the ion vibration time scale. However, the chaotic behaviour appears on the dust particles vibration time scale due to the relative streaming of the dust particles to the background plasma. Such instabilities may drive plasma irregularities that could affect radar backscatter from the clouds.

Theoretical investigations are carried out for the cylindrical magnetosonic solitary waves in dissipative, hot electron–positron–ion plasma. By the reductive perturbation technique the modified Korteweg–de Vries–Burgers equation (mKdVB) is obtained and its approximate analytical solution is given. Using this solution, the effects of different physical parameters on magnetosonic solitary wave in cylindrical geometry are discussed. The results may have applications in laboratory and space plasmas.

In a recent Comment, Chang et al. [Phys. Plasmas 29, 114703 (2022)] have studied the electron dynamics for an electron accelerating in a tightly focused Gaussian laser pulse with the higher order correction terms, and it is found that the initial position of the electron is the reason why the electron is pushed to the − z axis at the end. In this Reply, the electron dynamics and its nonlinear Thomson backscattering in a tightly focused Gaussian laser pulse with the higher order correction terms are presented, and it is found that the result is consistent with the lowest order approximation case in our paper [Hong et al., Phys. Plasmas 29, 043102 (2022)]. Meanwhile, it is also found that when the longitudinal deceleration effect of the ponderomotive force on the electron introduced by the falling part of the tightly focused laser pulse is greater than the longitudinal acceleration effect of the rising part, the electron that is initially stationary will be slightly pushed to the − z axis at the end, which can well explain the “return” phenomenon of the electron in the longitudinal direction both in our paper and in the Comment.

Based on a density gradient model proposed recently by Imran and Khan, a new heterogeneous traffic flow model considering time and lateral distance is proposed. The type and stability of the equilibrium solution of the model are discussed by using the differential equation theory, and the global distribution structure of the trajectory in the phase plane is analyzed. In addition, the density wave stability conditions and saddle-node bifurcation conditions of the model are studied, and the solitary wave solutions of the KdV equation in the metastable region are derived by using the reduced perturbation method. The numerical results show that the new model cannot only reproduce the spatiotemporal oscillation phenomenon when walking and stopping, but also describe the sudden change behavior of traffic near the critical point of saddle-node bifurcation. It is shown that the model can reproduce some complex traffic phenomena qualitatively.

Incident wave reflection and transmission caused by the impurity in one-dimensional bead chain are studied. As the number of impurities increases, the energy of the transmitted and reflected waves oscillates periodically. When the number of impurities is so large that its length is greater than the width of the incident wave, the transmission and reflection remain constant. In this paper, the dependence of the energy of transmitted and reflected waves on the number of impurity particles in each segment is studied. It is noted that both the reflection and the transmission depend not only on the numbers and the permutation of the impurity but also on the parameters of the incident wave. This behavior can be used to detect the impurities in the bead chain by measuring the reflection of an incident wave.

For possessing high tolerance to oxidation and radiation damage under irradiation of high fluence heavy ions, nano-laminated Cr2AlC is a better candidate material when used as the functional material in high temperature and nuclear reactors. In this study, the mono-vacancy defect-related properties in Cr2AlC have been investigated by first-principle calculations. The results indicate that the C vacancy could be easily formed due to its low formation energy. It is inferred that the vacancy-mediated migration in Cr2AlC is energetically most favorable for Al vacancy, which can be a proof for elucidating the good oxidation tolerance of Cr2AlC under an oxidizing environment. The conductivity of Cr2A1C will be reduced by the formation of vacancies, while its theoretical Vickers’ hardness will be slightly increased. On the other hand, the bulk modulus will be increased through the introduction of mono-vacancy, which will have a negative impact on the shear modulus and the brittle performance of Cr2AlC. In view of the present work, we propose that Cr2AlC can be excellent material for the applications in extreme environments according to our study based on the first-principle calculation.

The electron dynamics and the Thomson backscattering spectra for an electron accelerating in a tightly focused Gaussian laser pulse are first investigated in detail. It is found that for a tightly focused Gaussian laser pulse, the ponderomotive force introduced due to the non-uniform intensity distribution of the laser pulse has the tendency to push out the electron from the laser pulse, which leads to the trajectory symmetry-breaking of the electron and then the generation of the even-order harmonics at the same time. Further, for the tightly focused Gaussian laser pulse, changes in several laser parameters, such as the increase of the laser peak amplitude, lengthening of the pulse width, and decrease of the beam waist, lead earlier to the relative ejected position of the electron to the laser pulse, which causes the more obvious trajectory symmetry-breaking of the electron, and then the more intensive peak intensity of the even-order harmonics. It is different from the well-known results of the plane waves and the Gaussian laser pulse with uniform transverse intensity distribution and provides a possible way for the generation of the even-order harmonics in nonlinear Thomson backscattering.

The head-on collision between two dust-acoustic solitary waves in a non-magnetized, collisionless and strongly coupled dust plasma has been studied. The application scope of the analytical solution of the head-on collision is given in the present paper by using the particle-in-cell simulation method. It is noted that the analytical results are valid if the amplitudes of both of the solitary waves are small enough. The effects of the coupling parameters on both the head-on collision and the waveform are also studied in the present paper.

We translate three-dimensional magnetohydrodynamic equations describing the bounded plasma into a one-dimensional case and obtain an equivalent damping force that resulted from both the bounded geometry and the viscosity of the plasma by averaging all the physical quantities on the cross section, which is perpendicular to the wave propagation direction. A damping solitary wave propagating in a viscous bounded plasma is also verified by the particle-in-cell simulation method. The results in the present paper may be useful in the study of charged beam and particle acceleration, etc. Moreover, we can devise an experiment to obtain the viscosity coefficient of the plasma by measuring the ratio of two amplitudes at two different points.

An enriched and domesticated bacteria consortium of sulfate-reducing bacteria (SRB) was used to treat wastewater from zinc pyrithione (ZPT) production, and the effects of different reaction parameters on sulfate reduction and zinc precipitation were evaluated. The single-factor experimental results showed that the removal rates of Zn2+ and SO42− decreased with an increased ZPT concentration ranging from 3.0 to 5.0 mg/L. Zn2+ and SO42− in wastewater were effectively removed under the conditions of 30–35 °C, pH 7–8 and an inoculum concentration of 10%–25%. The presence of Fe0 in the SRB system enhanced Zn2+ and SO42− removal and may increase the resistance of SRB to the toxicity of Zn2+ and ZPT in wastewater. A Box–Behnken design was used to evaluate the influence of the main operating parameters on the removal rate of SO42−. The optimum parameter values were found to be pH 7.45, 33.61 °C and ZPT concentration of 0.62 mg/L, and the removal rate of SO42− reached a maximum of 91.62% under these optimum conditions.

By using the equation of the state of P = α d + β d T d, we studied a shock wave propagation in a strongly coupled complex plasma. A Korteweg-de Vries–Burgers equation is obtained to describe a shock wave in strongly coupled complex plasma. Dependence of the shock wave speed on the piston velocity and the plasma parameters such as the screening parameter of the strongly coupled complex plasma are given analytically for a weak shock wave. It is in good agreement with previous results. It shows in the present paper that there are density oscillations in the postshock region which is similar to that found in the previous works. Dependence of the length between two first peaks of the density oscillation on the piston velocity and the plasma parameter are also given analytically which is also in agreement qualitatively with previous results.

Supersoliton (SS) can be mainly featured in two ways, namely, by focusing on subsidiary maxima on its electric field or by meeting the requirement that the appropriate Sagdeev pseudopotential (SP) has three local extrema between the equilibrium conditions and its amplitude. In this paper, by using the SP method, double layers and ion-acoustic SSs are studied in a plasma with Maxwellian cold electrons, nonthermal hot electrons, and fluid ions. The existence of the SS regime in parameter space is obtained in a methodical fashion. The existence domains for positive solitary waves are also presented. It is found that there is no SSs at the acoustic speed.

Theoretical studies are carried out for ion acoustic solitons in multicomponent nonuniform plasma considering the dust size distribution. The Korteweg−de Vries equation for ion acoustic solitons is given by using the reductive perturbation technique. Two special dust size distributions are considered. The dependences of the width and amplitude of solitons on dust size parameters are shown. It is found that the properties of a solitary wave depend on the shape of the size distribution function of dust grains.

We investigate atomic interaction induced localization of a spin–orbit coupled Bose-Einstein condensate loaded in a double-well potential. We confirm the existence of the localization in the presence of the spin–orbit coupling for differences between the spin-dependent nonlinear atomic interaction strength between intraspin and interspin. We find a quantum phase transition from spin balance to spin localization for the different strengths of nonlinear atomic interaction strength. We also obtain the parametric dependence of the transitions to spin localization. The results play a constructive role to control spin localization of spin–orbit coupled Bose-Einstein condensate in a double-well potential.

An overdamped three-layer model with incommensurate structure consisting of two harmonic chains which both move over the substrate potential is studied in the presence of an external (Formula presented.) driving force. The force is applied only on the upper harmonic chain, and dynamics of the middle layer is examined. The results show that the dynamical mode-locking appears not only in the upper layer but also in the middle one. The behavior of the middle layer is strongly determined by the amplitude and frequency of the ac force, and the phase diagram which presents pinned, dynamical mode-locking and sliding regimes as a function of system parameters are given. Contrary to the standard case, critical depinning force and steps exhibit anomalous behavior. Particles trajectories have been analyzed which showed very different motion of particles from the one which usually appears in systems under (Formula presented.) forces.

The transmission and the reflection of a shock wave by one or several impurities in viscoelastic bead chains is studied in the present paper. There is only one reflected wave for a single impurity. The amplitude of the beads oscillation increases as the initial velocity of the boundaries beads increases, while it decreases as the viscosity coefficient increases. Two reflected waves will be produced if the impurity number is larger than a critical value. This critical value depends on both the initial velocity and the viscosity coefficient. In addition, the maximum amplitude of reflected wave is a constant, when the viscosity coefficient is large enough.

By using the PIC simulation method and theoretical investigation from both the magnetohydrodynamic equations and the Vlasov equation of the dusty plasma produced by the relative streaming of the dust fluid and the background ionospheric plasma, we investigate the instability of the waves excited by this kind of the dust beam in the ionosphere. It is found that the waves are stable in both the electron and ion vibration time scales, while they are unstable in the dust grain vibration time scale. It is inferred that the wave is the high hybrid wave in the electron vibration time scale. The dispersion relations of the perturbed waves in both the electron vibration and ion vibration time scales are obtained. As the time increases until it arrives at the dust grain vibration time scale, the instability appears for the perturbed wave. Such instabilities may drive plasma irregularities that could affect radar backscatter from the clouds, when the wave satisfies the Bragg condition for backscatter. By using the dispersion relation of waves in both electron vibration and ion vibration time scales, we can infer what kind of radar backscatter can be possibly affected by the instability of the perturbed waves.

Both the linear and the nonlinear magnetosonic wave in a multi-component dusty plasma are studied in the present paper. The dependence of the dispersion relation of the linear waves on the dust size distribution are given. It seems that the larger the difference between the maximum and the minimum radius of the dust grains, the lower the wave frequency for all cases of the dust size distribution. Furthermore, it is noted that the width, the amplitude and the propagation velocity of the KdV solitary wave depend on the dust size distribution, especially it depend on whether the number density of the larger sized dust grain is larger or smaller than that of the smaller sized dust grain. For the power law dust size distribution, the width and the propagation velocity of the KdV solitary wave between the maximum and the minimum radius of the dust grains is larger than that of mono-sized dusty plasma.

A two-dimensional particle-in-cell simulation is carried out to study the focusing effects of the long proton beam propagating in background plasmas. It is found that the smooth beam, with the long length and the small density gradient profile, is focused to high density. The sharp beam, with long length and the large density gradient profile, is modulated into many high density and periodic short beam pulses due to the wakefield induced by the beam. In addition, increasing the plasma density and adopting the non-uniform plasmas are the effective ways to reduce the wakefield.

The solitary waves of a viscous plasma confined in a cuboid under the three types of boundary condition are theoretically investigated in the present paper. By introducing a three-dimensional rectangular geometry and employing the reductive perturbation theory, a quasi-KdV equation is derived in the viscous plasma and a damping solitary wave is obtained. It is found that the damping rate increases as the viscosity coefficient increases, or increases as the length and width of the rectangle decrease, for all kinds of boundary condition. Nevertheless, the magnitude of the damping rate is dominated by the types of boundary condition. We thus observe the existence of a damping solitary wave from the fact that its amplitude disappears rapidly for a → 0 and b → 0, or v' → + ∞.

1-D particle-in-cell simulations are used to investigate the propagation and decomposition of the ion acoustic solitary waves (IASWs) in plasmas. Our results show that for small-amplitude conditions, IASWs are stable and the simulation results are consistent with the theoretical predictions of the reductive perturbation method. As the amplitudes of IASWs increase, the waves become unstable and trains of oscillating waves are emitted behind the main waves. When the amplitude is large enough, the wave cannot exist and will decay into a series of waves with a small amplitude. By comparing our simulations with the theoretical solutions of Kortewag–de Vries soliton, the upper limitation of the amplitude of IASWs in plasmas is found. Moreover, our results show that although the reductive perturbation method is valid only for small perturbations, the application scope of the reductive perturbation method can be expanded to describe the potential profiles of IASWs with any amplitude. Meanwhile, the application scope for the density profiles is still limited in the perturbation cases.

First-principles calculations are performed to study the effects of defect on the structure and electronic properties of Ti3SiC2. The calculations show that the formation energy of Si vacancy is minimal compared with the Ti or C vacancies in Ti3SiC2. The defects of Si layer also can be formed under high-temperature or irradiation environments. The C-layers or Ti-layers are almost impossible to form. If the Si vacancy or Si layers are formed, they prefer to be substituted by the O and H atoms to form the MXene structure, and the unit cell of Ti3SiC2 lattice constant decreases in c-direction. However, it has quite slight effect on electronic properties of Ti3SiC2. The He impurities are almost impossible to occupy the Si vacancies, because the formation energy are 50.860 eV for one layer of Si atoms substituted by the He atoms. This type of defect leads to the lattice constant of Ti3SiC2 in c-direction increasing considerably. Therefore, Ti3SiC2 is a suitable candidate for nuclear materials because of the high-formation energies of He impurities under irradiation environment.

Evolution of both low-frequency harmonic Alfvén wave train and Alfvén solitary wave is studied by using the compressible MHD fluid model. A critical point is found at which linear wave theory should be replaced by a nonlinear one. A small, but finite amplitude Alfvén solitary wave is numerically found. The head-on collision between an Alfvén wave train and an Alfvén solitary wave is also numerically investigated. An interesting result is that there is no phase shift for both colliding waves which is different from that between two KdV solitary waves.

Zn alloys containing Fe element suffer from the detrimental effect of coarse FeZn13 or (Fe, Mn)Zn13 second phase in Zn matrix on mechanical properties, especially on ductility. The key reasons are the peritectic reaction of Fe and Zn at high temperatures and negligible solid solubility of Fe in Zn at low temperatures. Taking a recently developed biodegradable Zn–Mn–Fe alloy as the base alloy, it is revealed that minor additions of Y and Nd rare-earth elements can significantly refine (Fe, Mn)Zn13 phase. With a total addition of 0.14%, the average size of blocky (Fe, Mn)Zn13 particles reduces about 43%, while the average length of lath-like (Fe, Mn)Zn13 particles reduces about 50%. Sphere-like (Y, Nd)Zn12 particles serve as effective nucleating agents for (Fe, Mn)Zn13 and MnZn13 with nearly the same lattice parameters. As a result, yield strength, the ultimate tensile strength, and elongation to failure of the base alloy increase by 30 MPa, 27 MPa, and 6%, respectively. Cell viabilities of the alloys with or without rare-earth additions are all over 100%, indicating good biocompatibility.

A two-dimensional particle-in-cell (PIC) simulation is carried out to study the wakefield and stopping power for a hydrogen ion beam pulse with low drift velocity propagation in hydrogen plasmas. The plasma is assumed to be collisionless, uniform, non-magnetized, and in a steady state. Both the pulse ions and plasma particles are treated by the PIC method. The effects of the beam density on the wakefield and stopping power are then obtained and discussed. It is found that as the beam densities increase, the oscillation wakefield induced by the beam become stronger. Besides, the first oscillation wakefield behind the bunch is particularly stronger than others. Moreover, it is found that the stationary stopping power increases linearly with the increase of the beam density in the linear/semilinear region.

The effects of $$s$$ -wave scattering length ( $$a_{sc}$$ ) of superfluid Fermi gas and energy bias ( $$\gamma $$ ) between two wells have been investigated on tunneling of superfluid Fermi gas in double wells. Interesting phenomena are observed and the explanations are given. We find that both the scattering length $$a_{sc}$$ and energy bias $$\gamma $$ affect the quantum transition dramatically. At certain regime, the complete population transfer between two modes can be obtained. However, at other regimes, the quantum transition can be completely blocked. Their dependence on $$a_{sc}$$ and $$\gamma $$ are given in this paper.

The monovacancy formation energies of each element Nb, Ge and C in the MAX phase Nb2GeC are obtained by ab initio calculation in the present paper. It is noted that the vacancy of each element has a slight effect on the hybridization bonding. If there is a vacancy of either Ge or C, the hybridization bonding will be slightly reduced. However, if there is a Nb vacancy, the hybridization bonding will be increased between the d-orbital and p-orbital. In contrast, the vacancies can substantially reduce the conductivity of the MAX phase Nb2GeC. It is also noted that if there is a vacancy of either Ge or C, the hardness of the Nb2GeC decreases, while it is increased if there is a Nb vacancy.

The properties of a high energy short pulse electron beam in a magnetic mirror field are studied numerically by the Particle-in-Cell method. The complex nature of processes studied, and also the need for the calculation of the positions, velocities, and trajectories of billions of particles, required the use of a scalable parallel algorithm. The use of modern supercomputers has allowed us to calculate the plasma dynamics, to determine the electron beam in the magnetic mirror field. Mathematical modeling of non-neutral plasma dynamics at the trap is carried out. The axially integrated radial density profiles, electric field distribution, and phase space distribution of velocity are measured. The axial and radial oscillations of a confined non-neutral plasma are also observed.

Numerical and theoretical investigations are carried out for the stability of the dust acoustic waves (DAWs) under the transverse perturbation in a two-ion temperature magnetized and collisionless dusty plasma. The Zakharov-Kuznetsov (ZK) equation, modified ZK equation, and Extended ZK (EZK) equation of the DAWs are given by using the reductive perturbation technique. The cut-off frequency is obtained by applying higher-order transverse perturbations to the soliton solution of the EZK equation. The propagation velocity of solitary waves, the real cut-off frequency, as well as the growth rate of the higher-order perturbation to the solitary wave are obtained.

MAX phases captured attention ever since they were synthesized. They are suited for different applications, especially in high-temperature and extreme environments. So knowledge of mechanical properties is essential for our applications of MAX phases in different situations. Cr2AC (A = Al, Ge) compounds belong to M2AX phases. But, few of their physical properties have been studied. This work demonstrated the compression behavior of Cr2AC (A = Al, Ge) by first-principles method. The elastic constants were calculated in the range of 0–50 GPa, it is shown that they satisfy the requirement of mechanical stability. The values of bulk moduli, shear moduli, Young’s moduli, Possion’s ratio and Lame’s constant were calculated. We also studied brittleness/ductility of Cr2AC(A = Al, Ge). For the more, we studied the dependence of a/a0, c/c0 and bulk moduli on the pressure below 50 GPa. In the end, we calculated the Mulliken bond overlap and theoretical hardness. We also discussed the bonding and antibonding.

Explanation for the damping of electromagnetic (EM) waves propagating in a plasma is given. Comparisons of the damping rates between a general plasma (with no dust grains) and a dusty plasma are given. It is found that, in a certain range of the EM waves, the damping rate in the dusty plasma is much larger than that in a general plasma. The damping rate mainly depends on the number density of the dust grains and the frequency of the EM waves.

A novel antenna for UHF radio-frequency identification (RFID) readers with circular polarization (CP) operation is proposed in this paper. The antenna consists of a 50 Ω microstrip feed line, two resonant paths on the upper surface of the substrate, and a system ground on the lower surface of the substrate. By adjusting the parameters of the two resonant paths, a circularly polarized reader antenna with good impedance matching can be obtained. Experimental results show that the proposed design exhibits good performance in term of circularly polarized radiation, and both the impedance bandwidth (931 MHz to 960 MHz) and the 3 dB axial-ratio bandwidth (948 MHz to 954 MHz) meet the Japanese RFID requirement (950 MHz to 954 MHz). Furthermore, the proposed antenna offers the following advantages: compact size (60 mm × 60 mm × 0.8 mm), simple structure, ease of fabrication, and low cost.

In mineral exploration, the apparent resistivity and apparent frequency (or apparent polarizability) parameters of induced polarization method are commonly utilized to describe the induced polarization anomaly. When the target geology structure is significantly complicated, these parameters would fail to reflect the nature of the anomaly source, and wrong conclusions may be obtained. A wavelet approach and a metal factor method were used to comprehensively interpret the induced polarization anomaly of complex geologic bodies in the Adi Bladia mine. Db5 wavelet basis was used to conduct two-scale decomposition and reconstruction, which effectively suppress the noise interference of greenschist facies regional metamorphism and magma intrusion, making energy concentrated and boundary problem unobservable. On the basis of that, the ore-induced anomaly was effectively extracted by the metal factor method.

In the adiabatic limit, we study Rosen–Zener transition of superfluid Fermi gas in a double well potential. We find that s-wave scattering length of the system can affect the quantum transition dramatically. At certain regime the complete population transfer between two wells is observed. On the contrary, the quantum transition could be completely blocked in other regime. We have derived analytical expressions for the transition probability. We also find that, in the adiabatic limit, the population difference between two modes always oscillates around its corresponding fixed point during Rosen–Zener transition process. The difference between population imbalance and the corresponding fixed point decreases with the adiabatic condition becomes stronger. The numerical simulation show a power law relation between them. It is verified by the Rosen–Zener transition for superfluid Fermi gas in the limited cases of both deep Bose-Einstein condensate regime and unitarity regime.

The dynamical phenomena of the Landau–Zener tunneling of the superfluid fermi gases in a double-well potential in deep BEC regime is investigated in this paper. The contribution of the higher order term representing the lowest approximation of beyond mean field corrections is considered. By using the corresponding classical Hamiltonian of the system, the fixed points and adiabatic energy levels are studied. The critical parameter for the number of fixed points evolution from two to four is obtained. For the nonlinear Landau–Zener tunneling, the tunneling probability with sweeping rate α is numerically given. At the adiabatic limit, the tunneling probability is not zero in certain regime, while it goes to zero in the other regime. Exponential dependence of the transition probability on the sweeping rate α in certain case is obtained.

This article proposes a meandered printed loop antenna for the fourth generation (4G) mobile system applications. Using a coupling strip connected with a 50 Ω microstrip fed-line on front side, the loop antenna on back side is excited and a half wavelength (0.5 λ) resonant mode and its higher modes are successfully resonated. A plane copper strip connected at top of the loop antenna is used to increase the antenna's path and to decrease the lower operation band to cover LTE 700 band. Two 15 nH ceramic chip inductors, which are embedded in the loop antenna, are used to decrease the antenna's 1 and 1.5 λ resonant modes. The 0.5, 1, and 1.5 λ resonant modes get together to form a broad lower operation band (693–1031 MHz) for LTE 700 and GSM 850/900 applications. Beside, the antenna's higher resonant modes are also excited to form a broad higher operation band (1668–2781 MHz) for DCS, PCS, UMTS, LTE 2300, LTE 2500, and WLAN applications. The proposed antenna also has an advantage of small size, which is 114 × 50 mm2 including a loop antenna of 14 × 50 mm2 and a ground plane of 100 × 50 mm2. With the advantages of board band, compact size, low cost, and good performance, the proposed antenna appears to be an optimal candidate for the 4G mobile applications. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2157–2163, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26997

This article proposes a compact printed meander loop antenna for the fourth generation (4G) mobile system applications.The total length of the meander loop operates a one-wavelength resonant mode (mode 1) at 774 MHz. To increase the antenna's operation bandwidth, this article uses coupled-fed feeding method that contains a coupling patch connected with a 50-Ω microstrip feed line. By applying the coupled-fed method, a new one-wavelength resonant mode (mode 2) is excited. After carefully adjusted the size of coupling patch, the frequency of mode 2 shifts to 904 MHz combining with mode 1 to form dual broad operations bands. The measured dual broad bands from 658 to 963 MHz and from 1658 to 2693 MHz can be applied in the 4G mobile system, especially for the long-term evolution application. The two resonant modes are resonated by 1λ loop type that has less influence by changing the size of ground plane. The antenna portion and overall dimensions of the proposed antenna are 20 × 60 × 0.8 mm3 and 120 × 60 × 0.8 mm3 suitable for today's mobile phone application. With the advantages of board band, compact size, low cost, and good performance, the proposed antenna appears to be a promising candidate for the 4G mobile applications. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1900–1907, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26927

A monopole slot antenna with compact size designed at WLAN band (2.4–2.484 GHz) is proposed for multiple-input multiple-output application. By the concept of electromagnetic shield, the antenna module is formed by an open-ended monopole slot surrounded by another open-ended monopole slot on the ground plane. The two identical folded antenna modules located on the both side of the ground plane are separated by an isolated element for increasing isolation more than 17.8 dB within the operating band. To increase antenna's bandwidth, the two open-ended monopole slot antennas with different lengths are printed to obtain two resonant modes, which are close at around 2.4 GHz. In addition, the proposed antenna occupies a small area of 10.5 × 20 mm2 and can be easily fabricated on an FR4 substrate that is a commonly used circuit board. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1103–1107, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26740

By considering the contribution of the higher order term representing the lowest approximation of beyond mean field corrections, we have investigated the effect of energy bias to the Josephson oscillation and self-trapping of superfluid Fermi gases in a double-well potential in deep BEC regime. Five phase states of Josephson oscillation (JO), oscillation-phase-type-self-trapping (OPTST), similar-oscillation-phase-type-self-trapping (SOPTST), running-phase-type-self-trapping (RPTST) and similar-running-phase-type-self-trapping (SRPTST) are found. The dependence of these five phase states on the dimensionless interaction parameter y = 1/(k F a sc ) and the initial system energy are given in this paper.

In this article, a meandered monopole antenna is designed to cover the global system for mobile communication (GSM900), digital communication system, personal communication system, universal mobile telecommunication system (UMTS) and WLAN 802.11b applications. The size of antenna is 12 mm × 42 mm, and that of ground plane is 60 mm × 42 mm. A 50-Ω microstrip line with length of 25 mm is used to feed the monopole antenna. The proposed antenna is designed a meandered current path to resonate three frequency bands centered at 900, 1800, and 2400 MHz. By adjusting the width of the meandered strip, good impedance bandwidths for the five application bands can be achieved. The detailed configuration of the proposed antenna and experimental results are presented and discussed. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:2216–2221, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26298

This article proposes a compact and small printed monopole antenna for wireless local area network (WLAN) applications.The substrate used in this design is an FR4 substrate with a permittivity of 4.4, which is an inexpensive and widely used printed circuit board (PCB). The overall dimensions of the proposed antenna (25 × 20 × 1.6 mm3) can be easily applied in todays portable wireless products. The low-frequency band centered at 2.4 GHz is resonated by the coupling between the U-liked ground plane and 50-ohm microstrip feed-line. When the rectangular patch A is added on the ground plane, the high-frequency band centered at 5.48 GHz is obtained. Because of the different polarization direction, the radiation patterns of low-frequency band in X-Z plane are similar to that of high-frequency band in Y-Z plane. The 10-dB impedance bandwidths (2.39–2.52 and 4.97–6.07 GHz) meet the WLAN application bands. With the advantages of dimension, cost, and performance, the proposed antenna appears to be a promising candidate for WLAN applications. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26089