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Objective: The role of hypoalbuminemia throughout the course of chronic periprosthetic joint infection (PJI) remains poorly understood. This study aimed to determine the prevalence and risk factors of hypoalbuminemia in periprosthetic joint infection (PJI) patients and to explore the association between hypoalbuminemia and treatment outcomes. Methods: This retrospective cohort study included 387 PJI cases who underwent two‐stage exchange arthroplasty between January 2007 and August 2020, of which 342 were reimplanted. The mean follow‐up period was 7.9 years. Multivariate logistic regression analyses were performed to identify risk factors for hypoalbuminemia and to assess the effect of hypoalbuminemia at 1st‐ and 2nd‐stage exchange on the treatment outcome. Furthermore, the impact of dynamic changes in hypoalbuminemia was investigated. Results: The prevalence of hypoalbuminemia at 1st‐ and 2nd‐stage exchange was 22.2% and 4.7%, respectively. Patients with age ≥ 68 years and those with isolation of Staphylococcus aureus, Streptococcus, or Gram‐negative bacteria exhibited a higher risk of hypoalbuminemia. Hypoalbuminemia at 1st‐stage was significantly related to treatment failure (OR = 3.3), while hypoalbuminemia at 2nd‐stage raised the OR to 10.0. Patients with persistent hypoalbuminemia at both the 1st‐ and 2nd‐stage exchanges had a significantly higher rate of treatment failure than patients with hypoalbuminemia at the 1st‐stage but normal albumin levels at the 2nd‐stage exchange (55.6% vs 20.0%, p = 0.036). Conclusion: One in five patients with chronic PJI exhibits hypoalbuminemia. Hypoalbuminemia is more likely to develop in patients of advanced age and those infected by specific highly virulent organisms. Also, our results highlight the close association between hypoalbuminemia and treatment outcomes. [ABSTRACT FROM AUTHOR]

The establishment of a financial system should not only consider the current situation, but also need to refer to the past. Due to the memory of the fractional derivative, a fractional-order system can more effectively describe the historical significance of the financial system. Most scholars use the prediction–correction scheme to study fractional-order systems. This paper provides a higher-precision numerical method for the financial system, which more effectively simulate the system. Based on the definition of the Grünwald–Letnikov fractional derivative, the integer-order system with nonconstant demand elasticity is extended to the fractional-order setting, and its dynamic behavior is studied, with some novel chaotic attractors found. The research results are helpful for improving the understanding of the financial system and the financial market and for predicting financial risks. [ABSTRACT FROM AUTHOR]

This paper is devoted to the backward problem of determining the initial value and initial velocity simultaneously in a time-fractional wave equation, with the aid of extra measurement data at two fixed times. Uniqueness results are obtained by using the analyticity and the asymptotics of the Mittag-Leffler functions provided that the two fixed measurement times are sufficiently close. Since this problem is ill-posed, we propose a quasi-reversibility method whose regularization parameters are given by the a priori parameter choice rule. Finally, several one- and two-dimensional numerical examples are presented to show the accuracy and efficiency of the proposed regularization method. [ABSTRACT FROM AUTHOR]

Five new 3,4- seco -lanostane triterpenoids, named ganocochnoids A−E (1−5), along with three known analogues (6−8), were isolated from Ganoderma cochlear. The structures of these new compounds, including their absolute configurations, were characterized by 1D and 2D nuclear magnetic resonance (NMR), computational methods, and HRESIMS. In particular, the structure of compound 1 was confirmed through X-ray crystallographic analysis. The anti-inflammatory activity of all the compounds was evaluated in LPS-induced RAW264.7 cells. The Western blot assay indicated that compounds 4 and 5 were found to have inhibitory effects on iNOS protein expression as well as on mRNA levels of TNF-a , Il-1b , and Il-6 , and compound 4 also reduced COX-2 protein expression in LPS-induced RAW264.7 cells. [Display omitted] • Five new compounds were isolated from Ganoderma cochlear. • C-7 of all new compounds is replaced by a keto group compared to fornicatin F. • The antiinflammatory activity of compounds 4 and 5 was evaluated. [ABSTRACT FROM AUTHOR]

The cGAS (cyclic GMP-AMP synthase)-STING (stimulator of interferon genes) pathway promotes antitumor immune responses by sensing cytosolic DNA fragments leaked from nucleus and mitochondria. Herein, we designed a highly charged ruthenium photosensitizer (Ru1) with a β-carboline alkaloid derivative as the ligand for photo-activating of the cGAS-STING pathway. Due to the formation of multiple non-covalent intermolecular interactions, Ru1 can self-assemble into carrier-free nanoparticles (NPs). By incorporating the triphenylphosphine substituents, Ru1 can target and photo-damage mitochondrial DNA (mtDNA) to cause the cytoplasmic DNA leakage to activate the cGAS-STING pathway. Finally, Ru1 NPs show potent antitumor effects and elicit intense immune responses in vivo. In conclusion, we report the first self-assembling mtDNA-targeted photosensitizer, which can effectively activate the cGAS-STING pathway, thus providing innovations for the design of new photo-immunotherapeutic agents. [Display omitted] • A highly-charged ruthenium photosensitizer is designed as the photo-activator for cGAS-STING pathway. • Ru1 can self-assemble into carrier-free nanoparticles through π-π and p-π interactions. • Ru1 nanoparticles show potent photodynamic antitumor immunotherapeutic effects in bilateral subcutaneous 4T1 tumor models. [ABSTRACT FROM AUTHOR]

Seven pairs of enantiomeric phenylpropanoids (1a/1b–7a/7b), including eight undescribed phenylpropanoids (1a, 2a/2b, 3a, 5a, 6a/6b, and 7b) were found in the fruits of Crataegus pinnatifida Bge. The enantiomers were separated using chiral column and elucidated through various spectroscopic methods and quantum chemical ECD calculations. The tyrosinase inhibitory activity of enantiomers was tested in vitro. Among them, enantiomers 1a/1b displayed moderate tyrosinase inhibitory activities. The interaction patterns were further studied by molecular docking, and the results indicated compounds 1a/1b may bind in the active site near the copper atom and interacted with the hydrophobic areas in the active pocket. Practical applications: Melanins exist widely in organisms and will be produced more against environmental stresses. Without th enzymatic action of tyrosinase, melanin biosynthesis would be blocked. Thus, tyrosinase inhibitors have been developed to modulate melanin formation. In this study, the enantiomeric phenylpropanoid isolated from the fruits of C. pinnatifida Bge displayed moderate tyrosinase inhibitory activities. This work may provide foundations for further research on tyrosinase inhibitor from natural sources. [ABSTRACT FROM AUTHOR]

Metal complexes have shown great potential in cancer immunotherapy. This review briefly introduces the basic concepts and strategies of cancer immunotherapy and summarizes the recent discoveries on the immune effects of traditional platinum‐based anticancer compounds. In addition, we also outline the latest research progresses on metal complexes for cancer immunotherapy focusing on platinum, ruthenium, iridium, rhenium and copper complexes. Finally, the research perspectives and unsolved problems on the applications of metallo‐anticancer agents in cancer immunotherapy are purposed. [ABSTRACT FROM AUTHOR]

• Four isomorphic rare earth metal-organic frameworks with high stability have been prepared. • JXUST-43 exhibits the highest conductivity with the value of 7.38 × 10–5 S·cm-1 at 98 % RH and 55 °C. • J XUST-42 displays a significant magnetocaloric effect with -Δ S m max of 16.63 J kg-1 K-1 at 3 K with Δ H = 7 T. The presence of field-induced slow magnetic relaxation behavior with antiferromagnetic coupling is observed in JXUST-43. Four isomorphic rare earth metal-organic frameworks designated as {[(CH 3) 2 NH 2 ] 0.7 [RE 2 (BTDBA) 1.5 (lac) 0.7 (H 2 O) 2 ]·solvent} n (RE = Tb (JXUST-19), Eu (JXUST-29), Gd (JXUST-42), and Dy (JXUST-43), where JXUST denotes Jiangxi University of Science and Technology) have been synthesized derived from a benzothiadiazole tetracarboxylate ligand (4′,4'''-(benzo[c][1,2,5]thiadiazole-4,7-diyl)bis([1,1′-biphenyl]-3,5-dicarboxylic acid), H 4 BTDBA). They present chain-based three-dimensional structures with one-dimensional channels extending along the b -axis. Notably, the free [(CH 3) 2 NH 2 ]+ cations within the channels serve as proton carriers during proton conduction. All complexes demonstrate significant proton conductivity dependent on relative humidity and temperature. Among them, JXUST-43 displays the peak conductivity achieved 7. 38 × 10–5 S·cm-1. In terms of magnetic research, JXUST-42 exhibits potential as a magnetorefrigerant, reaching a maximum entropy change (-Δ S m max) of 16.63 J kg-1 K-1 at 3.5 K with Δ H = 7 T. And the presence of field-induced slow magnetic relaxation behavior with antiferromagnetic coupling is observed in JXUST-43. A series of isomorphic RE-MOFs (JXUST-19, 29, 42 and 43) are potential candidates for proton conduction and magnetic refrigeration. [Display omitted] [ABSTRACT FROM AUTHOR]

The scaled boundary finite element method (SBFEM) developed by Wolf and Song has shown certain parallels to the finite element method (FEM) and boundary element method (BEM). Because of its semi‐analytical nature, SBFEM is particularly suitable for the analysis of wave propagation in unbounded domains. This paper makes a certain modification of the standard SBFEM. A new idea of scaling surface instead of a scaling center is introduced to formulate the governing SBFE equations for the analysis of wave propagation in multilayered half‐space, which leads to simplifying the modeling and saving considerably the computational effort. In addition, by employing the proposed approach, some problems encountered in engineering practice, which are difficult to deal with by the conventional SBFEM, for example, 3D foundation impedance on half‐space with irregular geographical features, can be effectively solved. The proposed approach also helps to simplify the solution of shell structures. Numerical examples are provided to validate the accuracy and efficiency of the proposed approach. [ABSTRACT FROM AUTHOR]

There remain challenges for effectively synthesizing heterocycles containing both piperidine and pyridine rings, mainly due to the inefficient synthetic process mostly requiring long reaction times. This paper reports a simple and efficient method for the synthesis of [(3S,5R)-3-hydroxy-5-methylpiperidin-1-yl](2-methylpyridin-3-yl)methanone through six steps starting from D-pyroglutaminol. The key step involved the introduction of a chiral methyl group by alkylation of lithiated (3S,7aR)-3-phenyltetrahydropyrrolo[1,2-c]oxazol-5(3H)-one with methyl iodide, followed by reduction and rearrangement to generate a benzyl-protected piperidine intermediate. After deprotection and amide formation, the final product was obtained with an overall yield of 32% in a total time of ~80 h). With readily available and inexpensive starting material through an operationally simple process, the method holds potential for applications in organic synthesis of other piperidine- and pyridine-containing heterocycles. [ABSTRACT FROM AUTHOR]

Topological photonics has recently opened up a promising frontier for electromagnetic wave and light manipulation and has made great progress from unique physical concepts to novel practical photonic devices. Numerous works have discussed the realizations of chiral topological photonic states in magnetic photonic crystals with broken time-reversal symmetry; however, limited reports have been discussed to the achievements of antichiral topological photonic states. In this Perspective, we review recent progress in antichiral topological photonic states in magnetic photonic systems for the basic concepts, properties, and applications. Additionally, we provide an outlook for emerging frontier topics, promising opportunities, fundamental challenges, and potential applications for antichiral magnetic topological photonics. [ABSTRACT FROM AUTHOR]

We propose a controllable topological add-drop filter based on magnetic–optical photonic crystals. This add-drop filter is composed of two straight waveguides and a hexagonal photonic crystal ring resonator. The waveguide and ring resonator are constructed by three different honeycomb magnetic–optical photonic crystals. The expanded lattice is applied with an external magnetic field so that it breaks time-reversal symmetry and the analogous quantum spin Hall effect simultaneously. While the standard one and the compressed one are not magnetized and trivial, the straight waveguide supports pseudospin-down (or pseudospin-up) one-way states when the expanded lattice is applied with an external magnetic field of +H (or −H). The ring resonator possesses multiple resonant modes which can be divided into travelling modes and standing modes. By using the travelling modes, we have demonstrated the function of the add-drop filter and realized the output port control by changing the direction of the magnetic field. Moreover, a large tunable power ratio from near 0 to 52.6 is achieved by adjusting the strength of the external magnetic field. The structure has strong robustness against defects due to the topological protection property. These results have potential in wavelength division multiplexing systems and integrated topological optical devices. [ABSTRACT FROM AUTHOR]

• A novel scaled boundary transformation of the geometry is proposed. • An improved scaled boundary element method for layered half-space is developed. • The radiation damping at infinity is satisfied strictly. • The horizontal layered and discontinuous layered half-space are analyzed. In this paper, a modified scaled boundary finite element method is proposed to deal with the dynamic analysis of a discontinuous layered half-space. In order to describe the geometry of discontinuous layered half-space exactly, splicing lines, rather than a point, are chosen as the scaling center. Based on the modified scaled boundary transformation of the geometry, the Galerkin's weighted residual technique is applied to obtain the corresponding scaled boundary finite element equations in displacement. Then a modified version of dimensionless frequency is defined, and the governing first-order partial differential equations in dynamic stiffness with respect to the excitation frequency are obtained. The global stiffness is obtained by adding the dynamic stiffness of the interior domain calculated by a standard finite element method, and the dynamic stiffness of far field is calculated by the proposed method. The comparison of two existing solutions for a horizontal layered half-space confirms the accuracy and efficiency of the proposed approach. Finally, the dynamic response of a discontinuous layered half-space due to vertical uniform strip loadings is investigated. [ABSTRACT FROM AUTHOR]

Key message: Ogura CMS fertility-restored materials, with 18 chromosomes, normal seed setting, stable fertility and closer genetic background to the parent Chinese kale, were successfully developed in B. oleracea via a triploid strategy for the first time. Ogura cytoplasmic male sterility (CMS) is the most widely used sterile type in seed production for commercial hybrids of Brassica oleracea vegetables. However, the natural Ogura CMS restorer line has not been found in B. oleracea crops. In this study, the triploid strategy was used with the aim to create euploid B. oleracea progenies with the Rfo gene. The allotriploid AAC hybrid YL2 was used as a male parent to backcross with Ogura CMS Chinese kale. After successive backcrosses, the BC2Rfo-positive individual 16CMSF2-11 and its BC3 progenies, with 18 chromosomes, were developed, which were morphologically identical to the parent Chinese kale. Compared with F1 and BC1 plants, it showed stable fertility performance, and regular meiosis behavior and could produce seeds normally under natural pollination. The genomic composition analysis of Rfo-positive progenies by using molecular markers showed that more than 87% of the C-genome components of BC3Rfo-progenies recovered to the parent Chinese kale, while most or all of the An-genome segments were lost in 16CMSF2-11 and its progenies. The results suggested that the genetic background of Rfo-positive individuals was closer to that of the parent Chinese kale along with backcrossing. Hereof, the Ogura CMS fertility-restored materials of Chinese kale were successfully created via triploid strategy for the first time, providing a bridge for utilizing the Ogura CMS B. oleracea germplasm in the future. Moreover, our study indicates that the triploid strategy is effective for transferring genes from B. napus into B. oleracea. [ABSTRACT FROM AUTHOR]

Summary: A novel approach is proposed to deal with the problem of wave scattering and diffraction of subsurface cavities embedded in stratified half‐space. The subsurface cavity with complex surroundings is treated as a substructure. The continuity condition at the interface between the substructure and the far field of stratified half‐space is maintained by applying a free‐field approach. As the boundary of the free‐field ground is regular, the construction of the dynamic matrices and the evaluation of the wave input on the interface become considerably easier. Based on the previous work with some improvement, a novel approach for evaluation of Green's functions in stratified half‐space is presented. The wave equation is decoupled into the one for SV‐P wave components and the other one for SH wave component. The precise integration technique ensures high accuracy of the solution of wave equations. The layer merging technique and the dual form equation make it possible to obtain Green's function in closed‐form solution of matrix equations. Numerical examples validate accuracy and efficiency of the proposed approach. [ABSTRACT FROM AUTHOR]

We present a general theoretical approach that combines the iterative technique with the nonlinear transfer matrix method to solve the general problems of three-wave mixing with pump depletion in nonlinear multilayer structures. The theoretical model is directly derived from nonlinear coupled wave equations, shows fast numerical convergence and maintains conservation of total energy perfectly for general structures. We have employed this approach to discuss second harmonic generation in photonic bandgap crystals with slow light effect and obtained a conversion efficiency of about 25% for both the forward and backward second harmonic waves. The detailed wave evolution process and energy conversion mechanism of sum frequency generation and difference frequency generation in perfect and imperfectly quasiphase-matching structures have been systematically investigated and their subtle and strong dependence on the initial conditions of incident waves has been revealed. The developed theoretical approach can be very useful for efficient and quantitative analysis of various nonlinear optical problems and help to design optimum nonlinear multilayer structures for specific high-efficiency nonlinear three-wave mixing processes. [ABSTRACT FROM AUTHOR]

Light transmitting through a subwavelength slit on an ordinary metal plate is diffracted to all directions but if the exit plane of the slit is patterned with periodical nanostructures, the diffracted light may be compressed into a collimated beam within a small angle. In this paper, we develop a rigorous theoretical method for solving the surface wave induced beam collimation in nanostructured subwavelength metallic slits. The method combines the analytical modal expansion method, the supercell technique, the transfer-matrix method, and the conventional Kirchhoff’s diffraction theory. It allows for quantitative investigation of coupling of the incident light into the guided wave of the slit and coupling of the guided wave out of the nanostructured exit plane. We have used the method to examine light transmission through the nanostructured metallic slit and the corresponding diffraction and beam collimation behaviors. We have extensively analyzed the angular transmission spectrum as a function of the nanostructure period and the incident light wavelength and revealed the condition at which good beam collimation can take place. The result shows that the beam collimation is caused by the excitation of the surface waves supported on the periodical nanostructured pattern and subsequent coupling into the radiation light. Several scattering channels can coexist for coupling the surface waves into the observed diffraction waves and they can act constructively to create one or more collimation beams with excellent directionality and high brightness. The diffraction field patterns in the large area confirm the angular spectrum analysis. [ABSTRACT FROM AUTHOR]

We fabricate periodic arrays of simple-square and composite-square air hole nanostructures on a 120 nm thick Au film deposited on glass substrate by focused ion beam technology and study their optical properties by examining the optical near-field distribution via scanning near-field optical microscopy in the near-infrared region. The simple-square nanostructure only contains one square air hole in each unit cell, while the composite-square one contains the same size square air hole in the center and eight smaller square air holes in the periphery. The measured optical near-field patterns for the two nanostructures show very different distribution features. High intensity light spots locate within the central square air hole in the simple-square structure, while they sit at the peripheral smaller square air holes in the composite-square structure. Numerical simulations based on the plane-wave transfer-matrix method have been carried out to analyze the optical near-field patterns for the two metallic nanostructures and agree well with the experimental data. The results indicate that light interaction with metallic nanostructures is very sensitive to even a small change in the subtle geometrical feature. Meanwhile, by comparing near-field patterns with dielectric nanostructures theoretically, we also find that optical confinement is better for gold nanostructures than for dielectric nanostructures. [ABSTRACT FROM AUTHOR]

Optical waveguides are characterized by high-efficiency transmission of electromagnetic (EM) waves and optical cavities have frequency selective property. The combination of optical waveguides and cavities can result in a large amount of devices in optical integrated circuit, among which a channel-drop filter is an important member. A three-dimensional (3D) woodpile photonic crystal (PC) can possess a complete band gap that allows perfect confinement of EM waves. We theoretically and experimentally study the property of the x-type waveguide and acceptor-type defect cavity that are created in the 3D woodpile PC working in the microwave regime. On the basis of resonant coupling between the x-type wave guide and acceptor-type cavity, a series of three-port in-plane-type channel-drop filters are built: single-cavity, double-cavity, three-cavity, and four-cavity channel-drop filters. All of them exhibit good frequency responding property by changing the size of cavity. The multicavity channel-drop filter demonstrates the possibility to build multichannel wavelength division multiplexers in the 3D PC platform. [ABSTRACT FROM AUTHOR]

We examine the optical properties of three-dimensional metallic photonic crystals made from a periodic stacking of thin metallic mesh layers separated by homogeneous dielectric films by means of a combination of the plane-wave-based transfer-matrix method and analytical modal solution approach. Although each metallic mesh layer can serve as a frequency-selective surface and involves an intrinsic long-wavelength waveguide cutoff to electromagnetic waves, pass bands and new band gaps can exist far below the cutoff frequency due to the global coupling effect among different mesh layers. The results for the transmission spectra and photonic band structures are in good agreement with existing experimental measurements. It is found that the position of the pass bands and band gaps strongly depends on the thickness and composite of the separation layer between the adjacent metallic mesh layers. [ABSTRACT FROM AUTHOR]

Transfer-matrix methods have been routinely used to calculate the transmission and reflection spectra of electromagnetic waves propagating through a photonic crystal slab. In this article we show that the intrinsic lattice symmetries within a photonic crystal can be used to reduce numerical computations of the electromagnetic problem. We have employed this lattice-symmetry enhanced transfer-matrix method to handle two-dimensional photonic crystal slabs of square and triangular lattices and three-dimensional layer-by-layer photonic crystal slabs. The calculated transmission spectra agree excellently with the photonic band structures in predicting the photonic band gap positions, indicating the accuracy and efficiency of this proposed approach. [ABSTRACT FROM AUTHOR]

Theoretical models have been developed to investigate the reflection and transmission spectra, and photonic band structure for a midinfrared layer-by-layer metallic photonic crystal. It is found that photonic band gap effects due to global coupling between different unit cells in different layers play a key role in the formation of the lowest stop band gap extending to zero frequency and a high transmission passband adjacent to the stop band gap. Excellent agreement of theoretical results with experimental measurements is achieved. [ABSTRACT FROM AUTHOR]

Presents information on a study which described a theoretical analysis of thin film epitaxial growth monitored by differential reflectance. Principle of reflectance difference technique; Comparisons between experiments and theoretical evaluations; Conclusions.

Abstract In the study, a precise radiation boundary method (PRBM) is proposed to analyze the diffraction of elastic wave and dynamic stress concentration of a double-layered lining tunnel with a shock-absorbing layer embedded in a layered half-space. The dynamic response of the complex structure is obtained by using a substructure replacement technique, which transforms the complex scattering problem into a simple radiation one. The proposed method is applied to model the radiation condition of a boundary of a complex structure truncated from a multi-layered half-space in frequency domain. The proposed method is based on the precise integration algorithm which ensues the low computational effort and high accuracy. The accuracy and effectiveness of the proposed method are validated by comparing it with the results of extant studies. Finally, a comprehensive parametric study is conducted to investigate the effects of the complex geological structure (impedance ratio of layered soil and soft layer on surface) and complex constructions (double-layered lining and shock-absorbing layer) on the dynamic stress concentration of a composite-structure tunnel. The proposed approach exhibits a significant ability to analyze the response of a complex underground structure embedded in a layered half-space. Highlights • The PRBM satisfy the radiation condition and reduce the unknown variables. • Low computational efforts and the high accuracy of Green function in the layered half-space. • For arbitrarily irregular complex structures, no special treatment is needed. • A comprehensive set of results are shown to light on the dynamic response of the double-layer. [ABSTRACT FROM AUTHOR]

Abstract: Surface plasmon resonance (SPR) in noble metal nanoparticles and nanostructures offers an efficient means to transport and localize the energy of light into some nanoscale space regions called hot spots, where the electromagnetic field is enhanced by many orders of magnitude upon the incident light. This local field enhancement can induce very huge enhancement of Raman signal for a molecule embedded within the hot spot, which has tremendous applications in surface‐enhanced Raman spectroscopy (SERS) and tip‐enhanced Raman spectroscopy (TERS). Here, a discussion is presented on how to engineer this SPR‐enhanced Raman scattering from both the mesoscopic and microscopic levels. The mesoscopic level focuses on engineering and optimizing the geometric and physical configurations of plasmonic nanoparticles in order to have as large as possible electromagnetic field enhancement factor in the hot spot. The microscopic level focuses on investigating the light–molecule interaction (both chemical and physical) in the microscopic level, either classical or quantum, in order to have deep and complete understanding of the key microscopic issues influencing the Raman scattering and then exploring microscopic means to further enhance the Raman scattering as large as possible. Although in many situations these two scopes can be considered separately, there are also many situations where these two scopes need to be considered together. A prominent example, discussed here, is the critical role of molecule Rayleigh scattering in a plasmonic nanogap. Furthermore, several important issues are pointed out that need attention and caution in exploring and evaluating the quantitative SPR‐based Raman enhancement, including the quantum plasmonics correction, surface and interface electron scattering correction, and the validity of classical electromagnetics and electrodynamics approaches used in single and few atom scale plasmonics. [ABSTRACT FROM AUTHOR]

This paper is devoted to the numerical solution of wave scattering and diffraction problems. A substructure replacement technique is proposed for this purpose. By introducing an arbitrary auxiliary boundary, the scattering problem is solved as a simple radiation one. The proposed approach is effective for wave scattering and diffraction by surface irregularities, such as hills and valleys as well as by subsurface inhomogeneities, such as cavities, tunnels and pipelines buried in backfilled trenches. Irrespective of how complex the different types of surface irregularities and subsurface inhomogeneities are, the same input and the same treatment can be applied. It is equally applied to P, SV, SH and Rayleigh wave incidence. Results are validated by comparison with those available in the literature. A challenging test for rather higher frequency scattering of SH wave from a symmetrical shallow V-shaped canyon has been carried out. Well agreements have been achieved. The proposed technique is simple in theory and easy to implement numerically. [ABSTRACT FROM AUTHOR]

Switchable nanoscale devices can be implemented in heterostructures that integrate plasmonic nanostructures with functional active materials and hence hold great potential for nanoscale-integrated circuits. The phase-change material of vanadium dioxide (VO2) has reversibly switchable optical/electrical properties and huge contrast in its refractive index in the infrared spectral range between insulator and metallic states. In this work, we numerically demonstrate all-optical manipulation of switchable absorption effect using the heterostructure incorporating the plasmonic resonance of Au nanoantennas with vanadium dioxide. Compared with the planar control device (without Au nanoantennas), the proposed design exhibits a pronounced resonant field enhancement as well as polarization-insensitive and omnidirectional absorption response. Meanwhile, the proposed device shows a large switching contrast (from ~ 99.9 to ~ 10% in absorption efficiency) at the mid-infrared wavelength of 3609 nm. Interestingly, the resonance of the proposed device can be continuously tuned by varying the side length of the antennas or governing the metallization level of vanadium dioxide layer. The photothermal mechanism is further investigated by numerical model calculations, indicating that the resonant, antenna-mediated local heating occurs on a sub-nanosecond time scale of 0.26 ns under a quite low incident intensity of 1.9 × 106 W/m2, which is about 12.5 times reduced with respect to that of control device. Therefore, the hybrid strategy of plasmonic antennas and vanadium dioxide provides a conceptual framework of switchable metamaterials for actively steering in ultrafast, energy-efficient electronic and photonic devices. [ABSTRACT FROM AUTHOR]

This paper introduces the anode-via vertical field plate Schottky barrier diode (AVFP-SBD) structure as an enhanced breakdown voltage AlGaN/GaN SBD, using the 2-D ATLAS Silvaco software. The breakdown voltage enhancement is achieved by integration of the lateral field plate (LFP) and vertical field plate (VFP) into the AlGaN/GaN SBD. The simulation results indicate that the VFP not only provide a uniform electric field along the channel, but also distributes the internal electric field on the side of the anode evenly. We show that the proposed structure significantly enhances the breakdown voltage of the conventional AlGaN/GaN diodes, i.e., from −246 to −354 V. Moreover, optimal breakdown voltage of −2301 V is achieved using the SBD with anode-via both LFP and VFP, through an integration of the LFP into the AVFP-SBD. Such breakdown voltage enhancement is achieved without any deterioration in the forward characteristics of the diode. [ABSTRACT FROM AUTHOR]

This paper presents an experimental investigation on the flexural behaviour of reinforced concrete beams under the combined effects of freeze–thaw cycling and sustained loading. Thirteen beams (2000 × 250 × 150 mm) were fabricated and tested. Test parameters included four numbers of freeze–thaw cycles (20, 40, 60 and 80) and three levels of sustained load (0, 20 and 50% of the ultimate load of the control beam). After exposure, the beams were tested at room temperature under four point bending up to failure. The flexural behaviour was evaluated by studying the load-deflection curve, the ultimate load capacity, the ductility, the crack pattern and crack width and the evolution of the neutral axis depth. It was found that freeze–thaw cycles and sustained loading had significant effects on the flexural performance of reinforced concrete beams. [ABSTRACT FROM AUTHOR]

The plasmonic integrated circuit, a potential application of surface plasmon polaritons (SPPs), can manipulate an SPP wave propagating on a metal surface in a way similar to electronic circuits. Here, we propose the concept of three-dimensional (3D) SPP wave manipulation: control of an SPP wave propagating in both the horizontal direction and the vertical direction. A hole set in the film can guide an SPP wave in the vertical direction. In the horizontal direction, two holographic groove patterns are used to focus an incident SPP wave on one surface of the film to the hole and control the divergent SPP waves transmitted from the hole on the other metal surface, respectively. The holographic groove patterns are designed via the methodology of surface electromagnetic wave holography. 3D finite-difference time-domain method simulations show a good performance of the 3D manipulation via these designed holographic groove patterns. [ABSTRACT FROM AUTHOR]

Recently, the reproducing kernel Hilbert space methods(RKHSM) (see Wang et al (2011) [2]; Lin and Lin (2010) [3]; Wu and Li (2011) [4]; Zhou et al. (2009) [6]; Jiang and Chen (2014) [7]; Wang et al. (2010) [8]; Du and Cui (2008) [9]; Akram et al. (2013) [10]; Lü and Cui (2010) [11]; Wang et al. (2008) [12]; Yao and Lin (2009) [13]; Geng et al. (2014) [14] ; Arqub et al. (2013) [15]) emerged one after the other. But, a lot of difficult work should be done to deal with multi-point boundary value problems(BVPs). Our work is aimed at giving a new reproducing kernel method for multi-point BVPs. We do not put the homogenization conditions into the reproducing kernel space which can avoid to compute the reproducing kernel satisfying boundary conditions and the orthogonal system. Three numerical examples are studied to demonstrate the accuracy of the present method. Results obtained by our method indicate that new algorithm has the following advantages: small computational work, fast convergence speed and high precision. [ABSTRACT FROM AUTHOR]

Gyromagnetic photonic crystal (GPC) offers a promising way to realize robust transport of electromagnetic waves against backscattering from various disorders, perturbations and obstacles due to existence of unique topological electromagnetic states. The dc magnetic field exerting upon the GPC brings about the time-reversal symmetry breaking, splits the band degeneracy and opens band gaps where the topological chiral edge states (CESs) arise. The band gap can originate either from long-range Bragg-scattering effect or from short-range localized magnetic surface plasmon resonance (MSP). These topological edge states can be explored to construct backscattering-immune one-way waveguide and other nonreciprocal electromagnetic devices. In this paper we review our recent theoretical and experimental studies of the unique electromagnetic properties of nonreciprocal devices built in GPCs. We will discuss various basic issues like experimental instrumental setup, sample preparations, numerical simulation methods, tunable properties against magnetic field, band degeneracy breaking and band gap opening and creation of topological CESs. We will investigate the unidirectional transport properties of one-way waveguide under the influence of waveguide geometries, interface morphologies, intruding obstacles, impedance mismatch, lattice disorders, and material dissipation loss. We will discuss the unique coupling properties between one-wave waveguide and resonant cavities and their application as novel one-way bandstop filter and one-way channel-drop filter. We will also compare the CESs created in the Bragg-scattering band gap and the MSP band gap under the influence of lattice disorders. These results can be helpful for designing and exploring novel nonreciprocal electromagnetic devices for optical integration and information processing. [ABSTRACT FROM AUTHOR]

An electromagnetic (EM) rail launcher can accelerate a macroscopic object to >2~km/s. One of the main problems of a simple railgun is the ohmic heating to melt in some special places, which is caused by the current clustering property. The design theory and technologies for a practical EM launcher concept are analyzed. There are three kinds of factors contributing to the current clustering: 1) short path priority (SPP); 2) skin effect (SE); and 3) velocity SE (VSE). The method of splitting a bulky copper into multistrips can be used to overcome the current clustering. SPP can also be used to reject SE and VSE. Besides, the structure strength of copper, the sliding wear of copper rail, and the parameters' matching for optimal EM force are also considered. A practical EM launcher concept is proposed. After the primary structural design is accomplished, the optimal simulation on three kinds of 1/6 armature are carried out, and the results are compared. The optimal armature has a more uniformed current distribution among the three. As a quantitative result, the uniformity coefficient on the armature's head and the rails is \sim50\%. As a military weapon concept, the practical EM launcher has the following features: 1) large bore; 2) high pressure; 3) high reliability; and 4) high efficiency. The new concept work might promote the EM launcher research work. [ABSTRACT FROM PUBLISHER]

We design a series of W1 waveguide-like parallel-hetero cavities (PHCs) made from the combination of parallelhetero perturbation (PHP) waveguides and photonic crystal waveguides and investigate their optical properties. Spectral properties are calculated numerically using the three-dimensional finite-difference time-domain method. The resonant frequencies and quality factors are obtained for each type of PHC and comparisons are made among different types of PHC, which is helpful for predicting and understanding the properties of PHC and designing PHC based high-performance cavities. The PHCs can broaden the category of cavity design and find interesting applications in integrated optical devices and solid state lasers. [ABSTRACT FROM AUTHOR]

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 spectrum responses. [ABSTRACT FROM PUBLISHER]

Second harmonic generation (SHG) in a short nonlinear photonic bandgap (PBG) structure coated with distributed Bragg reflector (DBR) mirrors is theoretically investigated by means of an iteration approach that fully considers pump depletion. A total conversion efficiency of about 96% can be obtained in an optimized structure with a size scale of about 0.2 mm and at the modest pump intensity of about 0.133 MW/cm, which is four orders of magnitude more than that in a quasi-phase-matching (QPM) structure with the same sample length. Such a high conversion efficiency of SHG will greatly facilitate the success of short frequency conversion devices and all-optical integration in nanostructures. [ABSTRACT FROM AUTHOR]

In the seismic analysis of arch dams, the heterogeneity of the foundation rock is always not included with the use of assumption of a homogeneous half-space. This study is devoted to the analysis of dam-water-foundation rock interaction considering a complex layered half-space. For this purpose, a novel scaled boundary finite element method (SBFEM) for the analysis of 3D dam-foundation interaction is developed. The novel SBFEM can satisfy the radiation damping rigorously of a complex layered half-space, which overcomes the limit of scaling requirements and broadens the application of the original SBFEM. In addition, two efficient models in the framework of SBFEM have been established in the early research, respectively, to solve hydrodynamic analysis of dam-water interaction and free-field motion of an infinite canyon. Thus, based on the substructure method, a SBFEM procedure and the corresponding program, named SBFEM-LEACD, is developed to solve the earthquake analysis of arch dams considering a complex layered half-space. The response of an arch dam at the design stage in southwest China, where the foundation rock is idealized as three kinds of model: homogeneous half-space, horizontal layered half-space and inclined half-space, is analyzed to demonstrate the effect of the complex layered half-space. [ABSTRACT FROM AUTHOR]

Abstract: We introduce the principle of the plane-wave transfer-matrix method, a theoretical tool that we have recently developed systematically to solve optical problems of photonic crystals (PCs). In this formulation, the electromagnetic fields are expanded into superposition of plane waves associated with the crystal lattice, which facilitates access to many advanced Fourier analysis techniques. We briefly discuss the standard application of the TMM to solution of transmission, reflection and absorption spectra for a finite PC slab and photonic band structures for an infinite PC. Then we push the formulation further to handle wave propagation in semi-infinite PC crystal structures. The three-dimensional wood-pile PC is taken as an example to show the power of the theory. [Copyright &y& Elsevier]

Abstract: We investigate the dispersion behavior of localized defect modes supported by a defect layer sandwiched within two symmetric semi-infinite one-dimensional (1D) photonic crystals (PCs) that are made from two or three constituents of dielectric media via an analytic Bloch-mode approach. We analyze two kinds of formation mechanism of defect modes as the photonic band gap effect and total internal reflection effect, and find that defect-mode properties are influenced significantly by the stack sequences of the two semi-infinite background PCs relative to the defect layer. Such investigations allow people to control the defect-mode dispersion behavior and engineer the features of optical devices by simply changing the stack sequences of the background PCs. [Copyright &y& Elsevier]

• Two new transition metal coordination polymers (CPs) were synthesized. • Complex 2 displays excellent luminescence in the solid state and solution. • The therapeutic activity of these two compounds on neuropathic pain was evaluated. By using a tripodal ether-connector tricarboxylic ligand 1,3,5-tris(carboxymethoxy)benzene (H 3 TCMB) as the organic linker, two new transition metal coordination polymers (CPs) were synthesized via reaction of Zn(NO 3) 2 •6H 2 O or Co(NO 3) 2 •6H 2 O with H 3 TCMB ligand under the solvothermal reaction conditions, and their chemical formulae are [Co 3 (TCMB) 2 (H 2 O) 4 ] n • 4 n H 2 O (1) and [Zn 3 (TCMB)(μ 3 OH) 3 ] n • 0.5 n H 2 O (2). The single crystal X-ray diffraction study shows that complex 1 is a 2D layered network which is further extended into a 3D supramolecular network via H-bond interactions, and complex 2 shows a 2D layered structure based on a [Zn 3 (μ 3 OH) 3 ] n cluster-based unit. As expected, complex 2 displays excellent luminescence in the solid state and solution, and it could serve as an ultrasensitive fluorescent sensor for detection of 2,4,6-Trinitriphenol (PA). The therapeutic activity of these two compounds on neuropathic pain was evaluated. First, the expression levels of ephrinB receptor were detected via the real-time RT-PCR method, the results showed that ephrinB receptor expression levels in the sciatic nerve was significantly reduced by compound 1 , but compound 2 did not show such effect. Then, the EphB ligand content was determined through the ELISA test, the results indicated that compound 1 was found more effective than compound 2 in reducing the content of EphB in the sciatic nerve. [ABSTRACT FROM AUTHOR]

The development of bioinspired neuromorphic device is an essential step to build brain-inspired neuromorphic cognitive systems. While sustainable and renewable biomaterial is considered as an essential building block for bioinspired portable neuromorphic device. Here, albumen based protein gated oxide neuromorphic transistors capable of learning activities have been proposed. The albumen-based electrolyte film demonstrates a high specific capacitance of ~1.7 μF/cm2 at 1.0 Hz. The transistor demonstrates good electrical performances with high ON/OFF ratio of ~7.1 × 107 and a field-effect mobility of ~4.5 cm2/(V·s). Resistor loaded inverters are obtained by connecting a transistor and a resistor in series. Besides, short-term synaptic plasticities are mimicked on the proposed bioinspired neuromorphic transistor. The transitions from short-term memory to long-term memory and the learning-forgetting-relearning process are also successfully imitated. More importantly, target learning processes demonstrate a novel idea to accelerate the learning activities of neuromorphic transistor. The results indicate potential applications for the proposed bioinspired neuromorphic transistor in green neuromorphic cognitive systems. Image 1 • Albumen gated bioinspired neuromorphic transistors are fabricated. • The device exhibits good electrical performances and learning abilities. • Learning activities are accelerated based on target learning mechanism. [ABSTRACT FROM AUTHOR]

One of a very significant computer vision task in many real-world applications is traffic sign recognition. With the development of deep neural networks, state-of-art performance traffic sign recognition has been provided in recent five years. Getting very high accuracy in object classification is not a dream any more. However, one of the key challenges is becoming making the deep neural network suitable for an embedded system. As a result, a small neural network with as less parameters as possible and high accuracy needs to be explored. In this paper, the MicronNet which is a small but powerful convolutional neural network is improved by batch normalization and factorization, and the proposed MicronNet-BN-Factorization (MicronNet-BF) takes advantages about reducing parameters and improving accuracy. The effect of image brightness is reduced for feature recognition by the elimination of mean and variance of each input layer in MicronNet via BN. A lower number of parameters are realized with the replacement of convolutional layers in MicronNet, which is the inspiration of factorization. In addition, data augmentation is also been changed to get higher accuracy. Most important, the experiment shows that the accuracy of MicronNet-BF is 99.383% on German traffic sign recognition benchmark (GTSRB) which is much higher than the original MicronNet (98.9%), and the most influence factor is batch normalization after the confirmation of orthogonal experimental. Furthermore, the handsome training efficiency and generality of MicronNet-BF indicate the wide application in embedded scenarios. [ABSTRACT FROM AUTHOR]

Rigorous electromagnetic theory has been used to optimize elastomeric phase masks for generating sub-100-nm parallel lines by means of near-field photolithography J. A. Rogers et al., Appl. Phys. Lett. 70, 2658 (1997). In the near-field region, the scattering effect is so strong that the scalar theory is no longer adequate: A bright line was found adjacent to the dark line previously predicted by the scalar theory, and the widths of both lines were found to be insensitive to the refractive index of the photoresist. The simulation results are in good agreement with experimental studies, which showed that the bright and dark lines could be used to generate trenches and lines in a positive-tone photoresist by controlling the exposure time. Our simulations also indicate that parallel lines as small as 50 nm can be generated by adjusting the parameters of the phase mask. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Today, most of the real physical world problems can be modeled with variable-coefficient KdV–modified KdV (vcKdV–mKdV) equation. Besides, the solution methods and their reliabilities are the most important. Therefore, a high precision numerical method is always needed. In this paper, Fourier spectral method is applied to solve the space fractional generalized vcKdV–mKdV equation and the influence of fractional orders on numerical solution of the space fractional generalized vcKdV–mKdV equation is investigated. Numerical simulations in different situations of equation are conducted, including the propagation and interaction of the generalized ball-type, kink-type and periodic-depression solitons. From the numerical experiments pondered here and compared with the other methods, it is found that the numerical solutions match well with the exact solutions, which demonstrate that the Fourier spectral method is a satisfactory and efficient algorithm. [ABSTRACT FROM AUTHOR]

In order to stop and reverse land degradation and curb the loss of biodiversity, the United Nations 2030 Agenda for Sustainable Development proposes to combat desertification. In this paper, a fractional vegetation–water model in an arid flat environment is studied. The pattern behavior of the fractional model is much more complex than that of the integer order. We study the stability and Turing instability of the system, as well as the Hopf bifurcation of fractional order α , and obtain the Turing region in the parameter space. According to the amplitude equation, different types of stationary mode discoveries can be obtained, including point patterns and strip patterns. Finally, the results of the numerical simulation and theoretical analysis are consistent. We find some novel fractal patterns of the fractional vegetation–water model in an arid flat environment. When the diffusion coefficient, d, changes and other parameters remain unchanged, the pattern structure changes from stripes to spots. When the fractional order parameter, β , changes, and other parameters remain unchanged, the pattern structure becomes more stable and is not easy to destroy. The research results can provide new ideas for the prevention and control of desertification vegetation patterns. [ABSTRACT FROM AUTHOR]

We have provided two compact designs of on-chip silicon photonic crystal (PhC) AND and XOR logic devices, which can provide multiple logic functions through different input frequencies within one structure. Compared to the former ones, the overall size is short to 10a × 18a (approximately 4 × 8 μm2). The working principle of the structures is lead to the directional leakage of the center cavity and the signal contrast are reached to 5.7 dB of AND and -19.66 dB of XOR functions, which could have potential applications in the field of all-optical signal processing and integrated optical circuits. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to present an accurate and efficient element for analysis of spherical shell structures. Design/methodology/approach: A scaled boundary finite element method is proposed, which offers more advantages than the finite element method and boundary element method. Only the boundary of the computational domain needs to be discretized, but no fundamental solution is required. Findings: The method applies to thin as well as thick spherical shells, irrespective of the shell geometry, boundary conditions and applied loading. The numerical solution converges to highly accurate result with raising the order of high-order elements. Originality/value: The modeling strictly follows three-dimensional theory of elasticity. Formulation of the surface finite elements using three translational degree of freedoms per node is required, which results in considerably simplifying the computation. In the thickness directions, it is solved analytically, no problem of high aspect ratio arises and transverse shear locking can be successfully avoided. [ABSTRACT FROM AUTHOR]