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In this paper, we discuss the photonic spin Hall effect (PSHE) in the combined structure of periodic dielectric waveguides (PDWs) and photonic crystal waveguide (PCW). By controlling the polarization of the dipole source, we have successfully achieved the arbitrary manipulation of PSHE for the PDW guided mode in our structure. The advantage of PDW is that it can be designed to different shapes without the geometric constraints, and still maintains a relatively high transmission rate. Therefore, by further changing the structure, including the adjustment of the intersection angle between PDW and PCW, and the alteration of the straight PDW to the bending or bifurcated shapes, we find that the output of highly unidirectional PSHE is mainly determined by the intersection angle between PDW and PCW and almost independent of the detailed shape of PDW.

The photonic spin Hall effect (PSHE) can be realized in a photonic crystal (PC) slab, that is, the unidirectional Bloch surface wave can propagate along the surface of the PC slab under the excitation of elliptical polarized magnetic dipole. It is further proved that PSHE is caused by the interference of the component surface waves excited by the different components of the incident light, which is the so called component wave interference (CWI) theory. In addition, we also find that the spin of the surface wave oscillates periodically in space, and the oscillation period is a unit cell. In a unit cell, the average spin keeps the spin orbit locked. The results show that the spin separation can also be modulated by the position and the polarization state of the magnetic dipole.

The photon spin Hall effect can lead to the more general question of how to control all the light waves in a muti-channel structure (so-called complete control). To address this problem in general and thoroughly, a theoretical approach was established in this paper. Guided by this approach, the complete controls in several complicated structures are realized theoretically or numerically. We also represent this approach in the form of representation theory. The important works reported recently in this area were explained by this theory.

The control of scattering light direction by incident spin state offers a desirable and novel development opportunity for the nano optics and integrated optical devices. Here, the controllable propagation of light in multi-channel metal waveguide is investigated by analyzing and applying the symmetry between the light source and the system based on the component wave interference theory. The composite electric and magnetic dipoles are used to drive the selective scattering in a four-channel structure. We found that it is a very convenient and intuitive method to obtain the selective propagation direction by considering the symmetry. We also reveal that the spin-momentum locking is only the eigen property of the optical system, instead of the origin of unidirectionality.

The discovery of Photonic spin Hall effect (PSHE) on surface plasmon polaritons (SPPs) is an important progress in photonics. In this paper, a method of realizing multi-channel PSHE in two-dimensional metal-air-metal waveguide is proposed. By modulating the phase difference $$\phi$$ ϕ and polar angle $$\theta$$ θ of the dipole source, the SPP can propagate along a specific channel. We further prove that PSHE results from the component wave interference theory. We believe that our findings will rich the application of SPPs in optical devices.

Qi-Ge decoction (QGD), which is derived from the Huangqi Gegen decoction, contains three traditional Chinese herbs: Astragalus membranaceus (Huangqi), Pueraria lobata (Gegen), and Citri Reticulatae Blanco Pericarpium (Chenpi). Gastric mucosal damage caused by ethanol was prevented and alleviated by QGD. However, the role of QGD in protecting the liver from toxins has not been reported. High-performance liquid chromatography with diode-array detection was used to qualitatively analyze QGD. Positive control (silymarin 100 mg/kg/day), QGD (20, 10, or 5 g/kg/day), and Nrf2 inhibitor brusatol (0.4 mg/kg/2 d) were administered to rats for 7 days, and then, liver injury was induced by injecting 2 mL/kg 25% CCl4. After 24 h, blood and liver were collected for analysis and evaluation. QGD was found to contain 12 main components including calycosin, puerarin, and hesperidin. QGD treatment significantly reduced liver damage and decreased serum alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase activities. QGD increased superoxide dismutase and catalase activities, and glutathione levels, but decreased malondialdehyde levels in livers from CCl4-treated rats. Compared to rats treated with CCl4 alone, after QGD administration, mRNA and protein levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 were increased, while those of Kelch-like ECH-related protein 1 (Keap1) and cytochrome P450 (CYP)2E1 were decreased. However, these improvements in QGD were reversed by brusatol. In conclusion, QGD can achieve its hepatoprotective effect through an antioxidant mechanism by activating the Nrf2 pathway.

The main function of the curved superlens is to magnify or minify the image of the pattern cut onto the mask in a photolithograph device. It is found theoretically, in this paper, that the magnifying or minifying function deals with two important properties: one is the magnifying (or minifying) effect and the other is the image quality. The magnifying (or minifying) effect of a specific superlens device can be expressed by a linear function and the image quality can be guaranteed by a quadratic function. The ways to obtain the two functions have been demonstrated in this paper.

The finding of Photon Hall effect (PHE) on metal surface is an important progress in photonics, but it will be more practical if PHE can be realized in line-type waveguide. In this paper, we suggested a way to realize PHE in two-dimensional photonic crystal (PC) waveguide. Numerical simulation results show that the propagating direction and strength of light in the PC waveguide can be controlled by the polarization state of incident light. Different from the PHE on metal surface, the PHE in PC waveguide can be driven not only by circularly polarized light, but also by linearly polarized light. The PHE in PC waveguide can be attributed to the interference of the two component waves excited by the incident light.

A general method is proposed to describe the energy levels of the interface states in one-dimensional photonic crystal (PC) heterojunction [Formula: see text] containing dispersive or non-dispersion materials. We found that the finite energy levels of the interface states for the finite configuration can be described totally by the dispersion relation of the PC with a periodic unit [Formula: see text]. It is further found that this method is also applicable for the case of defect modes. We believe our method can be used to guide the practical application.

The generalized scattering coefficient (GSC) method is pedagogically derived and employed to study the scattering of plane waves in homogeneous and inhomogeneous layered structures. The numerical stabilities and accuracies of this method and other commonly used numerical methods are discussed and compared. For homogeneous layered structures, concise scattering formulas with clear physical interpretations and strong numerical stability are obtained by introducing the GSCs. For inhomogeneous layered structures, three numerical methods are employed: the staircase approximation method, the power series expansion method, and the differential equation based on the GSCs. We investigate the accuracies and convergence behaviors of these methods by comparing their predictions to the exact results. The conclusions are as follows. The staircase approximation method has a slow convergence in spite of its simple and intuitive implementation, and a fine stratification within the inhomogeneous layer is required for obtai...

The influence of lubrication on profile and flatness control during asymmetry self-compensating work roll (ASR) hot strip rolling process is studied in order to meet the requirement of schedule-free rolling (SFR) campaigns for non-oriented electrical steel production with identical strip width. The effects of lubrication on rolling force, surface topography, and work roll wear are analyzed through experimental data. A work roll wear model for a wide non-oriented electrical steel production considered lubrication during the hot rolling process is built, which can accurately reflect the work roll wear during the hot rolling process with lubrication. A 3D finite element model for roll stack considering lubrication is built. The effects of shifting strategy on ASR work roll wear contour, loaded roll gap crown, and edge drop are analyzed based on the models. The optimal shifting rhythm is 1, and the optimal shifting step is 2 ~ 3 mm. By combining the ASR technology with lubrication, the life of work rolls expands from 70 to 100 ~ 150 by different shifting step, the loaded roll gap crown can be efficiently controlled by bending force and the edge drop control ability can be improved efficiently within an entire rolling campaign.

A novel line-type optical one-way transmission structure is proposed, which consists of a helical subwavelength metal slit. The simulation results obtained from finite-difference time-domain method show that this structure has excellent one-way transmission properties. When a polarized light propagates forward through the structure, its polarization direction will be rotated 90 degree. The backward propagation is blocked.This helical slit can also be a one-way unit of a plane-type one-way transmission structure, in which the setting angle plays an important role in determination of the transmission properties of the one-way plane via the strong coupling effect between the waves in adjacent slits.

The continuous photon Hall effect excited in a surface plasmon polariton system is proposed and realized theoretically, in which the parallel incident light illuminates the small ball nearing the surface. The scattering direction can be continually modulated in the large range of almost 180 degree by the elliptical polarization state of the incident light. The physical reason is displayed intuitively by the component waves interference principle.

The zero-refraction property of a metal film can be used to image so that the metal film behaves as a superlens. Experimentally, the metal superlens is sandwiched between the photosensitivity resist (PR) and the dielectric spacer in the photolithograph device to produce images. In this paper, the imaging conditions of the metal superlens, or the parameters of the device containing the superlens are investigated in detail. It is found that the energy zero-refraction effect is the intrinsic property of the metal superlens. The permittivities of the dielectrics at the two sides of the superlens will influence the imaging quality. The rule is drawn for obtaining best images: the two dielectrics should have the same permittivities, so-called symmetry case, and the real part of the permittivity of the metal superlens plus the dielectric permittivity is just equal to 1, i.e. ϵ ( dielectric ) + ϵ r ( superlens ) = 1 .

In this paper, Dirac point method is used to study the interface state of one-dimensional photonic crystal heterojunction [Formula: see text] containing dispersive materials GaAs. We found that the energy levels of the interface states satisfy a simple sinusoidal function. We investigate the variation of the energy levels of the interface states with the incident angle, it is found that these interface states move toward high-frequency with the increase of the incident angle. At the same time, it is found that there is an extra localized band and it is further proved that the extra band corresponds to the defect band, and the energy levels of the defect band possess the same behavior with those of interface states.

A very facile way to obtain multiple interface modes in a one-dimensional photonic crystal heterostructure is proposed in this Letter. We found that the interface modes can be generated by introducing the interfaces, and the number of interface modes equals the number of introduced interfaces. All these interface modes originating from a different geometric Zak phase can create two band branches governed by the two different interfaces. We further find that the two band branches can be renormalized into one band branch with discrete energy levels in the form of sinusoidal function. We believe that these findings can be used to provide direct guidance for practical application and can also make the estimation of practical samples more convenient.

In this study, an analytical solution is proposed to solve the general problems of three-wave mixing with pump depletion. The so-called quasi-phase-matching (QPM) for χ ( 2 ) nonlinearities, including sum frequency generation (SFG), second harmonic generation (SHG) and difference frequency generation (DFG), is amended when the depletion of the pumping light power is considered. The optimum domain width and the corresponding conversion efficiency are discussed. The optimum domain widths deviate from the coherence length l c = π / Δ k , but the deviation is so small that it can be ignored according to the actual situation. The applicable scope of undepleted pump approximation (UPA) is estimated by a proposed relative tolerance. Analysis indicates that the relative tolerance showing the difference of conversion efficiency between the UPA and the exact solution is solely determined by the conversion efficiency. Based on the relative tolerance curves for SFG, SHG, and DFG, two models are developed: one can be used to describe the SFG and SHG processes, whereas the other can be used for the DFG process. These findings can be used to provide direct guidance for practical application, and can also make the estimation of practical samples more convenient.

We present theoretical study on developing a one-dimensional (1D) photonic crystal heterojunction (h-PhC) that consists of a monolayer molybdenum disulfide (MoS2) structure. By employing the transfer matrix method, we obtained the analytical solution of the light absorption and emission of two-dimensional materials in 1D h-PhC. Simultaneously enhancing the light absorption and emission of the medium in multiple frequency ranges is easy as h-PhC has more modes of photon localization than the common photonic crystal. Our numerical results demonstrate that the proposed 1D h-PhC can simultaneously enhance the light absorption and emission of MoS2 and enhance the photoluminescence spectrum of MoS2 by 2–3 orders of magnitude.

A tunable optical unidirectional device or optical isolator composed of a metal subwavelength grating covered with magneto-optical rotation medium is proposed. The results of a simulation show that the difference of transmissivity in opposite directions varies from 0 to 83% with an external magnetic field at room temperature. The largest field needed to control transmissivity is only 1.1 T, so the working conditions can be easily achieved. A theoretical method to calculate transmissivity is presented and the unique transmission characteristics of this new device are explained satisfactorily.

In this paper, the spalling causes of backup rolls in a roughing mill of a hot strip rolling mill were investigated. The roughing mill withstood extreme service conditions with long service cycles for backup and work rolls, a large variety of the same width rolling campaigns, severe and non-uniform wear contours of backup and work rolls. Analysis of cyclic stress applied on backup rolls indicated that contact stress played a dominant role in rolling contact fatigue which led to spalling on the backup roll surface. A 3D finite element model of roll system was established and contact stresses between rolls in whole service periods of backup and work rolls were calculated. The simulation results showed that roll wear had significant impact on contact stress distribution. In particular, the severe and non-uniform U-typed wear contours of work rolls led to produce huge contact stress peak in two sides of the rolls, where existed large cracks by eddy current inspection of post-service backup rolls. Backup rolls stood thousands of times stress cycle in a service period, they were liable to fatigue damage in these areas. A new backup roll contour was developed to improve contact stress distribution and no spalling accidents were happened any longer after applied to the roughing mill.

The mechanism of the unidirectional transmission in metal subwavelength gratings with different surfaces is investigated theoretically. This kind of unidirectional transmission belongs to the extraordinary optical transmission assisted by the surface plasmon polariton (SPP). The SPP wave comes through the multi-reflection process and finally transforms into the transmission wave. The difference of amplitude transmissivities and reflectivities at different surfaces in opposite incident directions results in the unidirectional transmission. A division method is proposed to calculate the parameters of subwavelength gratings with asymmetric surfaces.

This paper studies optical transmission through an interface between two slits with different widths in a sheet composed of an ideal conductor. Such a structure is of potential use in fabricating optical diode and may be the simplest one compared to other designs. Our calculations show that there is a critical wavelength. When the light wavelength is below the critical wavelength, the transmissivity is unidirectional. The expression of the stable transmissivity as a function of the ratio of the widths of the two slits was obtained analytically. Particularly, at the critical wavelength, the transmissivities are zero. This phenomenon has great potential for application in the manufacture of wavelength blockers.

The nanostructure of amorphous carbon thin film is described in terms of a disordered conductive sp2 phase embedded in an electrically insulating sp3 matrix. The conductive sp2 phase is dominated by Drude type free-carries response, and the carrier conductive between sp2 clusters is hopping. The two conductivities are in a serial configuration under a percolation approximation. In view of this, we extend Shimakawa’s model for compact nanoparticles [14] to amorphous carbon thin films in order to provide understanding on its terahertz (THz) optical complex permittivity. Furthermore, the contribution of phonons for THz optical complex permittivity is included in the scope of Debye theorem phenomenologically. Considering the condition of ω ω TO and the narrow frequency range, we interpret the complex phonon permittivity experimentally as e phonon = A ω e i θ for amorphous carbon. Thus, the real and imaginary permittivity can be simultaneously explained by the above considerations. It is the first qualified analysis on the THz optical properties of amorphous carbon thin films experimentally.

In this paper, the magnetic properties of ferromagnetic graphene nanostructures, especially the dependence of the magnetism on finite temperature, are investigated by use of the many-body Green’s function method of quantum statistical theory. The spontaneous magnetization increases with spin quantum number, and decreases with temperature. Curie temperature increases with exchange parameter J or the strength K2 of single-ion anisotropy and spin quantum number. The Curie temperature TC is directly proportional to the exchange parameter J. The spin-wave energy drops with temperature rising, and becomes zero as temperature reaches Curie temperature. As J(p,q)=0, ω1=ω2, the spin wave energy is degenerate, and the corresponding vector k=(p, q) is called the Dirac point. This study contributes to theoretical analysis for pristine two-dimensional magnetic nanomaterials that may occur in advanced experiments.

We investigate light transport in metal slits filled with a one-dimensional periodic stack of low- and high-index dielectric media. We have analytically extracted an exact independent-mode model where each transverse eigenmode is subject to its own Bragg scattering and dispersion modulation. The analytical model allows for easy analysis of the complex band structures calculated by means of the finite-difference time-domain method, where the physical origin of each band can be identified and assigned to a certain eigenmode of a metal slit. The analytical model is also very efficient and convenient to analyze the optical transmission spectra for these metal slits. The origin of all subtle spectral features can be discerned from the band diagram analysis of the relevant independent eigenmodes. A comparative study shows that the simple analytical independent-mode theory is powerful in handling the intrinsic light transport problems for periodically modulated metal slits and analyzing their complicated spectru...

Economic lot and scheduling problem is one of the focuses in the international engineering field. Aiming at several kinds of products and sets of production lines, this paper introduces a production model, which is based on the principles of artificial intelligence and introduces random factors as time changes, such as market demand and production line equipment. Besides, this paper puts forward a dynamic heuristic search production schedule method, and the simulation results show that the effectiveness and predictability of this method.

In this paper, the effect of Nb doping on the formation of O vacancies in rutile TiO2 is studied by the use of ab initio density-functional calculations. The formation energies are calculated at different doping concentrations (CNb) and the corresponding electronic structures are analyzed. It is shown that the formation energy is mainly determined by the structural relaxation. As CNb increases, the formation energy first increases and then decreases with the maximum in vicinity of CNb=11.1 at%. The investigation of electronic structures shows that the distribution of excess electrons, which is affected by the doping concentration and the types of oxygen vacancy, determines the relaxation and formation energy of oxygen vacancy. Our calculated results indicate that the formation of oxygen vacancy in rutile TiO2 can be most effectively suppressed by Nb doping in a large range of Nb doping concentration. This may be one of the reasons why the proper amount of Nb doping can improve the oxidation resistance of γ - TiAl .

The magnetic properties of ferromagnetic (FM) single-layered nanobelts are investigated if there exists a single-ion anisotropy. The magnetic quantities as functions of belt width and temperature are calculated. The spontaneous magnetization, area of the hysteresis loop. and energy level extension increase with belt width, and decrease with temperature. The Curie temperature increases with belt width. The energy spectra are calculated. When the belt width is fixed, a higher temperature leads to lower energy spectra. The spin-wave energy, as well as the energy level extension, drops with temperature rising, and becomes zero as the temperature reaches the Curie temperature. The results are compared with those of FM single-walled nanotubes. The Curie point T c of a nanobelt is always smaller than that of a nanotube, when the width of the former and the perimeter of the latter are equal, and the reason is analyzed.

We introduce a method to obtain and describe the multiple defect modes in the multiple photonic quantum-well structure [(AB)mC]n(AB)m. It is found that the relationship between structural parameters and defect modes can be obtained by analytically solving the dispersion relationship for the photonic crystal with its periodic unit [(AB)mC], and a laconic and unifying expression can be used to describe the energy levels of both the interface modes and defect modes. The internal mechanism to determine the related parameters is revealed. We believe that these findings can be used to provide direct guidance for practical application.

The magnetic behaviors of ferromagnetic single-walled nanotubes are systematically investigated by use of the many-body Green's function method of quantum statistical theory. The spontaneous magnetization, absolute value of ferromagnetic energy, area of hysteresis loop and coercivity increase with diameter of the tubes and spin quantum number, and decrease with temperature. Curie temperature increases with diameter and spin quantum number. As the diameter of the tube tends to infinity, all the numerical results approach to those of a two-dimensional monolayer. The dependences of initial susceptibility on temperature and diameter below and above Curie point are contrary. The calculated results are compared with experimental results where possible, and are qualitatively in agreement with the latter. The Curie temperature is determined by the tube diameter and independent of rolling helicities.

The adsorption of oxygen atoms on the Zr(0 0 0 1) surface is investigated by the use of ab initio total energy density functional methods within the generalized gradient approximation. Considering the repulsive interactions between the adsorbed oxygen atoms, a multiple-layer adsorption model (MLAM), in which the adsorbed oxygen atoms take the sites in different adsorption layers, was used. Our calculated results with a p(2 × 2) unit cell show that the surface face-centered cubic (SFCC) sites are the most favorable sites at the oxygen coverage of 0.25 monolayer (ML). However, the system with one oxygen adatom taking the SFCC sites and the other one taking the octahedral sites between second and third Zr layers (Octa(2,3)) is the most stable configuration at the coverage of 0.50 ML. As the oxygen coverage is increased to 1.0 ML, each of the oxygen atoms prefers taking the SFCC and octahedral sites such as Octa(2,3), Octa(4,5) and Octa(6,7) in the alternate layers, respectively. Our calculated results of the work functions with the MLAM successfully explain the interesting and unusual experimental work function changes upon oxygen adsorption. It should be noticed that the MLAM must be taken into account for oxygen adsorption on the Zr(0 0 0 1) surface.

We investigate one-dimensional nonlinear photonic crystals consisting of ferroelectric domains with the modulated polarization directions. Significant enhancement of second harmonic generation (SHG) is observed from numerical simulations when the frequency of fundamental wave is aimed at the photonic band edge. We devise the model structure with optimal configuration of the polarization directions of the ferroelectric domains in terms of simulated annealing algorithm. The conversion efficiencies of the ‘forward’ and ‘backward’ SHGs can be engineered.

The spontaneous emission (SE) behavior of the polarized atoms in a dielectric thin slab embedded in dielectric or metallic medium is analyzed. It is found that the SE rate of the polarized atoms in the vicinity of interface between the slab and surrounding medium can be considerably varied when changing the polarized direction of atoms. A switching operation of atomic SE between the inhibition and enhancement processes of the SE can be realized. In a dielectric thin slab embedded in metallic medium, the SE rate of the atoms near the dielectric–metal interface is enhanced greatly owing to the effect of surface-plasmon polaritons. Our findings imply that the tuning of the polarized orientation of atoms in the dielectric thin slab can effectively control the atomic SE processes.

We report an intense (∼10mW) and ultra-broadband (∼150 THz) THz to infrared (IR) source with a Gaussian wavefront, emitted from nano-pore-structured metallic thin films with femtosecond laser pulse excitation. The underlying mechanism has been proposed as thermal radiation. In addition, an intense coherent THz signal was generated through the optical rectification process simultaneously with the strong thermal signal. This unique feature opens up new avenues in biomedical research.

One kind of optical unidirectional transmission structures is proposed which is composed of a metal subwavelength slit dressed by one or two gratings. Simulation results show that the gratings with different geometry parameters can play different roles. One role is the convergence effect and the other is shield effect. Each effect can independently cause the unidirectional transmission with special properties. These two effects are explained in view of optical reciprocal theorem. Combination of the two effects results in excellent unidirectional transmission properties.

Terahertz (THz) spectroscopic sensing and imaging has identified its potentials in a number of areas such as standoff security screening at portals, explosive detection at battle fields, bio-medical research and so on. With these needs, the development of an intense and broadband THz source has been a focus of THz research. In this work, we report an intense (~10 mW) and ultra-broadband (~150 THz) THz to infrared (IR) source with a Gaussian wavefront, emitted from nano-pore-structured metallic thin films with femtosecond laser pulse excitation. The underlying mechanism has been proposed as thermal radiation. In addition, an intense coherent THz signal was generated through the optical rectification process simultaneously with the strong thermal signal. This unique feature opens up new avenues in biomedical research.

A new structure of negative-refractive-index material is proposed, which is composed of ferromagnetic wires setting in two-dimensional Bravais lattice (FWL) with the application of external magnetic field. The refractive index of the FWL consisting of ferrum wires arranged in square lattice is calculated. The refractive index exhibits negative value in the GHz region. A notable characteristic of the FWL is that the negative refractive index is tunable by the applied external field.

We calculate the omnidirectional dispersion spectrum for one-dimensional (1D) photonic crystals (PCs) inserting multiple photonic quantum-wells (PQWs) with the use of the plane-wave expansion method in combination with a supercell technique. We find that the localized defect modes significantly depend on the number of the PQWs and the configuration. This may provide a new way to engineer the dispersions of the composite PCs to meet the requirements of optical or microwave devices.

The parametric amplification (PA) and second harmonic generation (SHG) from quasi-one-dimensional aperiodic optical superlattices (AOSs) are investigated in the cases of large, intermediate, and small signals of the pumping light wave. The optimal design of the AOSs is carried out with the use of the simulated annealing (SA) method. The numerical simulations show that the constructed AOSs can achieve multiple wavelength PA (or SHG) with identical amplification (or identical conversion efficiency) at the pre-assigned wavelengths. The variations of the normalized intensities of the PA signal (or the pumping fundamental wave (PFW)) for the PA process with the distance of propagation of the light wave from the interface of the AOSs at the pre-assigned wavelengths exhibit monotonically increasing (or decreasing) behavior. So do the variations of the normalized intensities of the second harmonic wave (SHW) (or the fundamental wave (FW)) for the SHG. This strongly supports the fact that the contribution of each individual unit domain in the constructed samples to the PA (or SHG) is constructive accumulation, favorable for the PA (or SHG) process. The saturation phenomenon of the PA (or SHG) signal is observed.

We investigate the evolution of the band gap in one-dimensional (1D) photonic crystals (PC) with the gradual modifications of structural configurations from photonic quantum wells to PC heterostructures. The transmissive spectra are calculated with the use of scattering matrix method. We find that the transmissive spectra and confined states strongly depend on the structural configurations of samples.