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GRO J1008-57, as a Be/X-ray transient pulsar, is considered to have the highest magnetic field in known neutron star X-ray binary systems. Observational data of the X-ray outbursts in GRO J1008-57 from 2017 to 2020 were collected by the Insight-HXMT satellite. In this work, the spin period of the neutron star in GRO J1008-57 was determined to be about 93.28 seconds in August 2017, 93.22 seconds in February 2018, 93.25 seconds in June 2019 and 93.14 seconds in June 2020. GRO J1008-57 evolved in the spin-up process with a mean rate of − ( 2.10 ± 0.05 ) × 10−4 s/d from 2009 – 2018, and turned into a spin down process with a rate of ( 6.7 ± 0.6 ) × 10−5 s/d from Feb 2018 to June 2019. During the type II outburst of 2020, GRO J1008-57 had the spin-up torque again. During the torque reversals, the pulse profiles and continuum X-ray spectra did not change significantly, and the cyclotron resonant scattering feature around 80 keV was only detected during the outbursts in 2017 and 2020. Based on the observed mean spin-up rate, we estimated the inner accretion disk radius in GRO J1008-57 (about 1 - 2 times of the Alfven radius) by comparing different accretion torque models of magnetic neutron stars. During the spin-down process, the magnetic torque should dominate over the matter accreting inflow torque, and we constrained the surface dipole magnetic field B ≥ 6 × 10 12 G for the neutron star in GRO J1008-57, which is consistent with the magnetic field strength obtained by cyclotron line centroid energy.

Recently, the system parameters of Cygnus X-1, i.e., the black hole mass M, the orbital inclination i and the source distance D, have been updated. As the input constraints of the continuum-fitting method, it is necessary to refine the spin with these new parameters. The Hard X-ray Modulation Telescope (HXMT, also named Insight) was successfully launched on June 15th, 2017 in China. In this work, we analyzed spectra obtained by the Insight-HXMT during 2017-2018 and re-estimated the spin via the continuum-fitting method. We first re-estimated the spin using old parameters and found the dimensionless spin parameter to be a ⁎ > 0.934 (3σ), which is consistent with previous measurements both from the continuum-fitting and iron-line fitting methods ( Gou et al. 2011 , Gou et al. 2014 ; Fabian et al. 2012 , Walton et al. 2016 , Tomsick et al. 2018 ). Then, when the new parameters were applied, we obtained an increased spin: a ⁎ > 0.967 (3σ), which is also consistent with the recent measurement (Zhao et al. 2020, submitted to ApJ) and also confirms an extreme Kerr black hole lying in this system.

A new black hole X-ray binary (BHXRB) MAXI J1535-571 was discovered by MAXI during its outburst in 2017. Using observations taken by the first Chinese X-ray satellite, the Hard X-ray Modulation Telescope (dubbed as Insight-HXMT), we perform a joint spectral analysis (2-150 keV) in both energy and time domains. The energy spectra provide the essential input for probing the intrinsic Quasi-Periodic Oscillation (QPO) fractional rms spectra (FRS). Our results show that during the intermediate state, the energy spectra are in general consistent with those reported by Swift/XRT and NuSTAR. However, the QPO FRS become harder and the FRS residuals may suggest the presence of either an additional power-law component in the energy spectrum or a turn-over in the intrinsic QPO FRS at high energies.

We study the 2018 outburst of Aql X-1 via the monitor of all sky X-ray image (MAXI) data. We show that the outburst starting in February 2018 is a member of short-low class in the frame of outburst duration and the peak count rate although the outburst morphology is slightly different from the other fast-rise-exponential-decay (FRED) type outbursts with a milder rising stage. We study the partial accretion in the weak propeller stage of Aql X-1 via the MAXI data of the 2018 outburst. We report on the spectral analysis of 3 observations of Aquila X-1 obtained by Insight – hard X-ray modulation telescope (Insight-HXMT) during the late decay stage of the 2018 outburst. We discuss that the data taken by Insight-HXMT is just after the transition to the weak propeller stage. Our analysis shows the necessity of a comptonization component to take into account the existence of an electron cloud resulting photons partly up-scattered.

This paper makes the first attempt to establish a size-dependent finite element formulation by combining isogeometric analysis and a re-modified couple stress theory (RMCST) for anisotropic elasticity. The flapwise vibration of rotation composite microbeam with geometrical imperfection connected to a hub is explored. This paper employs the NURBS function as the basis function to describe the geometry and overcomes the inherent difficulty of constructing higher order continuous displacement function for modified couple stress theory based finite element formulation. Besides the angular velocity, slender ratio, scale parameter, and maximum imperfection amplitude, the effect of ply angle on the flapwise vibration of rotation composite microbeam is investigated in this paper for the first time. This investigation demonstrates that we can control the natural frequencies of rotating beam by designing composite laminates in different stacking sequences.

In this work, we present a NURBS-based finite cell approach for topology optimizations of structures with arbitrary shaped trimmed design domains. The combination of isogeometric analysis and finite cell method allows for a topology optimization of trimmed geometries directly derived from CAD systems which eliminates the time consuming preprocessing work such as mesh generations. We further propose a variationally consistent Nitsche's method for the weak enforcement of essential boundary conditions along trimming curves. Independent from the analysis domain, a high order and continuous NURBS represented density field is introduced which not only provides an intrinsic filter but also allows for the realization of multi-resolution topology optimizations. Additionally, we also propose a simple and straight forward method to enforce geometric constraints of arbitrary shapes during topology optimizations. We demonstrate the efficiency and accuracy of the proposed method with a number of benchmark problems and engineering oriented models.

Taking the von Karman geometrically nonlinearity into account, this paper presents a nonlinear finite element formulation of axially functionally graded(AFG) tapered microbeams, which is based on the modified couple stress and Euler–Bernoulli beam theory. The profiles of physical parameters such as elasticity modulus and mass density of the microbeam are assumed to be a simple power-law form along the length direction, while either width or height of the beam changes linearly in axial direction. The size-dependent nonlinear free vibration of AFG non-uniform microbeams is analyzed by using finite element simulation. The correctness of the present analysis is validated by comparing computed results with those available for AFG tapered beams. The effects of vibration amplitude, variation of the taper ratio in cross section and gradient index of material along the length and material length scale parameter as well as boundary conditions on nonlinear fundamental frequency are discussed.

Firstly, a multi-field coupling finite element formulation of composited beam laminated with the photostrictive actuators is developed in this paper. Moreover, an optimal fuzzy active control algorithm is also proposed on the basis of the combination of optimal control and fuzzy one. This method opens a new avenue to resolve the contradiction between the linear system control method and nonlinear actuating characteristics of photostrictive actuators. The desired control for suppressing multi-modal vibration of photoelectric laminated beam is firstly obtained through optimal control and then the fuzzy control is used to approach the desired mechanical strain induced by photostrictive actuators. Thus, the multi-mode vibration control of beam is realized. In the design process of optimal fuzzy controller, the design of fuzzy control is independent of optimal control. The simulation results demonstrate that the proposed control method can effectively realize multi-modal vibration control of photoelectric laminated beams, and the control effect of optimal fuzzy control is better than that of optimal state feedback control. Keywords: Active control, Finite element method, Multiple modes, Optimal fuzzy control algorithm, Photostrictive actuators

The constituent equations of both 0–1 and 0–3 polarized PbLaZrTi (PLZT) micro-cantilevers in the form of unimorphs and/or bimorphs are developed. These formulations are based on the modified couple stress theory (MCST), the laminated beam theory, and/or the Euler-Bernoulli beam theory. The thermo-electro-light-mechanical coupled fields and size effect were considered simultaneously in these equations. The present models can capture the size effect in virtue of a material length scale parameter (MLSP). The size-dependent tip deflection, equivalent bending moment and blocking force are discussed. Different materials and thicknesses of the elastic layer are considered in presented models. Furthermore, the present models can be reduced to the classical 0–1/0–3 polarized unimorph/bimorph.

The selective catalytic reduction (SCR) technology shall achieve a high NOx conversion efficiency but a limited reductant slip to satisfy the increasingly stringent Euro VI regulations. The physico-chemical model based non-dominated sorting genetic algorithm (NSGA-II) was applied here to gain the desired urea dosage feed ratio and achieve the optimal trade-off between NOx reduction and NH3 slip so that some benefits such as fuel and urea efficiency gains may be materialized; moreover, the dependence of the optimized solution on dynamic model was illustrated based on a sensitivity study and a reduced order one-state model was utilized to capture essential behaviors of the system under low computational burdens. Two different steady operating conditions were selected to validate optimal results from the model based NSGA-II method and conclude that they shall be in good agreement with acceptable errors. The optimization results were demonstrated by means of several typical cases where effects of the temperature and the space velocity on ammonia coverage ratio and NOx conversion efficiency were analyzed. In addition, the full load optimal maps for the engine were obtained based on our method to provide a reference or benchmark on the control system.

In this study, based on the new modified couple stress theory, the size- dependent model for nonlinear bending analysis of a pure 0–3 polarized PLZT plate is developed for the first time. The equilibrium equations are derived from a variational formulation based on the potential energy principle and the new modified couple stress theory. The Galerkin method is adopted to derive the nonlinear algebraic equations from governing differential equations. And then the nonlinear algebraic equations are solved by using Newton–Raphson method. After simplification, the new model includes only a material length scale parameter. In addition, numerical examples are carried out to study the effect of material length scale parameter on the nonlinear bending of a simply supported pure 0–3 polarized PLZT plate subjected to light illumination and uniform distributed load. The results indicate the new model is able to capture the size effect and geometric nonlinearity.

In this paper, a size-dependent model of clamped-clamped composite laminated electrostatic Euler–Bernoulli microbeams with piezoelectric layers attached was proposed based on a new modified couple stress theory for anisotropic elasticity. With the aid of Hamilton's principle, the nonlinear differential governing equation was established and solved by utilizing the generalized differential quadrature method. The present model, which can be reduced to the isotropic beam model takes the residual stresses, fringing effects and midplane stretching effects into consideration. A good agreement exists between numerical results of the present reduced model and those of available literature. Numerical analysis reveals that the size effect is significant when geometry sizes of a beam are comparable to the internal material length scale parameter (hereafter referred to as MLSP). Furthermore, the pull-in voltage dependence of the residual stress, midplane stretching, MLSP as well as the voltage applied to the piezoelectric layers are also investigated. The present model can accurately predict the static behavior and guide the design of composite laminated micro-beam actuated by both the electrostatic and piezoelectric forces.

Distinct enterotypes have been observed in the human gut but little is known about the genetic basis of the microbiome. Moreover, it is not clear how many genetic differences exist between enterotypes within or between populations. In this study, both the 16S rRNA gene and the metagenomes of the gut microbiota were sequenced from 48 Han Chinese, 48 Kazaks, and 96 Uyghurs, and taxonomies were assigned after de novo assembly. Single nucleotide polymorphisms were also identified by referring to data from the Human Microbiome Project. Systematic analysis of the gut communities in terms of their abundance and genetic composition was also performed, together with a genome-wide association study of the host genomes. The gut microbiota of 192 subjects was clearly classified into two enterotypes (Bacteroides and Prevotella). Interestingly, both enterotypes showed a clear genetic differentiation in terms of their functional catalogue of genes, especially for genes involved in amino acid and carbohydrate metabolism. In addition, several differentiated genera and genes were found among the three populations. Notably, one human variant (rs878394) was identified that showed significant association with the abundance of Prevotella, which is linked to LYPLAL1, a gene associated with body fat distribution, the waist-hip ratio and insulin sensitivity. Taken together, considerable differentiation was observed in gut microbes between enterotypes and among populations that was reflected in both the taxonomic composition and the genetic makeup of their functional genes, which could have been influenced by a variety of factors, such as diet and host genetic variation.

To investigate the composition and function of ocular surface microbiome in healthy people from different altitudes.Thirty-two healthy people living in a high altitude region and 30 sex- and age-matched individuals living in a low altitude region were enrolled. Samples were collected from the lower conjunctival sac of one randomly chosen eye for each participant. 16S rRNA sequencing was conducted to study the bacterial community composition and predict gene function using PICRUSt software.Microbial diversity and richness was significantly decreased in samples from highlanders as calculated by Abundance-based Coverage Estimator (ACE) index, Chao1 index, and observed-species index (all p 0.01). Principle coordinate analysis (PCoA) suggested significantly distinct clustering of the conjunctival sac bacterial communities between two groups (p = 0.03), especially the dominant genera. The relative abundances of Corynebacterium, Staphylococcus, and Anaerococcus were significantly enriched in highlanders, while those of Pseudomonas and Massilia were significantly decreased as compared with lowlanders (p 0.01). In the functional annotation analysis, we found that 74 gene pathways, mainly in metabolism, differed in abundance. Pathways related to immune system diseases and infectious diseases were also enriched in highlanders.The composition and function of ocular surface microbiome in highlanders were distinct from those of lowlanders and our study may provide a reference catalog of the healthy conjunctival microbiome in highlanders.

Epigenetic gene enhancer of zeste homolog-2 (Ezh2) is reported to be associated with ocular neurodegenerative diseases; however, its underlying mechanism is poorly understood. The present study aimed to determine the role of 3-deazaneplanocin A (DZNep), which inhibits the transcription of Ezh2 by reducing the trimethylation of histone 3 lysine 27 (H3K27me3), in a retinal ganglion cell (RGC) degeneration model. Retinal damage was caused by intravitreal injection of N-methyl-D-aspartate (NMDA). DZNep and the vehicle control were intravitreally applied immediately post-NMDA injection. The severity of retinal damage was evaluated by immunofluorescence and terminal deoxyribonucleotide transferase (TdT)-mediated dUTP nick end labeling (TUNEL) staining, and retinal function was determined by electroretinogram (ERG). The transcriptome was examined by RNA sequencing and quantitative PCR (qPCR). Microglial cells were detected by immunohistochemistry. DZNep significantly prevented the cell death in the ganglion cell layer (GCL) and inner nuclear layer (INL) induced by NMDA. DZNep preserved the ERG b- and a-wave amplitudes and the b/a ratio in NMDA-treated mice. Moreover, RNA sequencing and qPCR revealed that neuroprotective genes were upregulated and played an important role in preserving retinal cells. In addition, DZNep inhibited the NMDA-induced activation of microglial cells. Our results suggest that H3K27me3 controls RGC survival at the transcriptional and epigenetic levels. The absence of H3K27me3 deposition upregulates neuroprotective genes to protect RGCs. Therefore, DZNep, which inhibits Ezh2 activity, could be a novel therapeutic treatment for ocular neurodegenerative diseases.

Pyrolysis is the key step in biomass thermochemical conversion process. The network model can accurately predict the pyrolysis process but generally cannot incorporate the combustion and gasification sub-models due to its complexity. This paper used the Bio-CPD model to predict the pyrolysis products of softwood and hardwood respectively; based on the predicted results, two empirical-simple forms of pyrolysis models were further optimized. The ultimate kinetic parameters obtained are suitable for biomass pyrolysis at high heating rate. For softwood, after being optimized, the apparent frequency factor and E/R of single rate are 4.3106e + 07 s−1, 10042 K respectively. While for two-competing rates model, the parameters are, α1 = 0.75, α2 = 0.89, A1 = 7992 s−1, E1/R = 7000 K, A2 = 8.3e + 09 s−1, E2/R = 14520 K, respectively. The numerical simulation of biomass pyrolysis and combustion process were performed by using CFD code Ansys Fluent. The results reveal that the release of volatile predicted by the default parameters have a delay compared with the actual process and is not appropriate for biomass simulation, while the optimized parameters in two simple models are accurate enough to simulate the biomass pyrolysis at high heating rate (103–105 K/s).

In this paper, two size-dependent constituent equations for symmetrical/heterogeneous piezoelectric bimorph actuators are developed using the modified couple stress theory and the principle of minimum total potential energy. The present model involves an internal material length scale parameter used to capture the size effect. In the limit when the internal material length scale parameter goes to zero, this model reduces to classical (local) constituent equations available in the literatures. Exact solutions for the normalized static deflection are obtained as a function of the ratio of the actuator thickness to the internal material length scale parameter. The simulations show that the static deflection developed by the present model has a remarkable difference with those got by the classical constituent equations when the ratio of the beam thickness to the internal material length scale parameter is small. It is also observed that the stiffness of elastic layers show directionally opposite effects on tip deflections of symmetrical piezoelectric bimorph actuator and heterogeneous one.

The performance of the selective catalytic reduction (SCR) system has been confirmed to be distinctly affected by hydrothermal aging fault. In this paper, an observer based on the Unscented-Kalman-Filter (UKF) algorithm theory is designed to identify the states of hydrothermal aging so that the aging SCR can be more accurately and efficiently diagnosed and fault-tolerant controlled. Furthermore, a model reference adaptive controller (MRAC) based on the theory of Lyapunov is constructed to enhance the fault-tolerant control performance of SCR Simulation, on the basis of the diagnosis information of UKF observer. The simulations and comparisons are performed to verify the performance of aging diagnosis and fault-tolerant control. The corresponding results show that the UKF observer has better estimation accuracy and respond speed for SCR aging, simultaneously, the fault-tolerant control performance of SCR aging is also better.

Based on the Timoshenko beam theory, von Karman geometric nonlinearity assumption and the modified couple stress theory, this paper presents linear and nonlinear free vibration analysis of rotating two-dimensional functionally graded micro-beam with even and uneven porous distributions. The material properties vary along the axial and thickness directions. The NURBS function is employed as the basic one to overcome the inherent difficulty of constructing higher order continuous displacement function for modified couple stress theory based finite element formulation. The validity of the present simulation is validated by comparing numerical results with those available literatures for rotating functionally graded micro-beams. Finally, the effects of several parameters such as porosity, power law index, material length scale parameter, rotational speed and hub radius on dimensionless frequencies and nonlinear frequency ratios are discussed.

Based on the first-order shear deformation theory (FSDT) as well as isogeometric analysis (IGA), the static bending, free vibration and buckling analysis of porous bi-directional functionally graded (BDFG) plates are investigated in this paper. The bi-directional gradients vary along the thickness (z-) and x-axis directions according to the power law, and porosity distributions are divided into even and uneven types. With the help of Hamilton principle, the governing equations of porous BDFG plates are derived. Compared with other reported literatures, several examples reveal that the accuracy and convergence of the present IGA model utilizing cubic non-uniform rational B-splines (NURBS). The effects of aspect ratios, boundary conditions, porosity distributions and coefficients on static bending, free vibration and buckling analysis of porous BDFG plates are studied in detail. These results show that increasing the volume fraction of porosity makes considerable effects on the mechanical behaviors of porous BDFG plates. Moreover, the deflections, frequencies and buckling loads of BDFG plates with even porosity are quite sensitive to the variation of porosity coefficients.

In this paper, based on the strain gradient theory, a size-dependent porous axially functional gradient (AFG) flexoelectric Euler-Bernoulli nanobeam model is developed. A modified power-law formula incorporating porosity volume fraction is presented to describe material properties of porous AFG nanobeam, and two typical porosity distributions patterns are considered. The generalized differential quadrature method is employed to discretize governing equations into a series of linear algebraic equations, so that the static bending deflections and free vibration frequencies are calculated conveniently for various boundary conditions. The credibility of the present mathematical formulation and the associated numerical solution are validated by comparing the results in previous literatures. Parametric studies are performed to illustrate the effects of the flexoelectricity, material length scale parameters, functionally graded index, porosity volume fraction, porosity distribution patterns on the static bending and free vibration behaviors of porous AFG flexoelectric nanobeam. The numerical results may provide support for the application of porous AFG flexoelectric nanobeam in Nano-electro-mechanical system.

It has been a persistent challenge to quantify gas emissions from industrial byproducts and warfare agents for environmental protection purposes, especially to detect multiple gas species using one device with high sensitivity and selectivity. To overcome this issue, a photonic crystal fiber (PCF)-based spectroscopic absorption sensing platform is proposed. We combine the PCF and long-period grating (LPG), two fundamental elements of fiber optics, into one functional unit to investigate the coupling properties of various PCF cladding modes. Further, we synchronize the PCF–LPG with a tunable Er-doped fiber ring laser into a thermo-stable and compact absorption spectroscopic sensor as a proof-of-concept for gas sensing. Because the Er-doped fiber ring laser can be tuned within the C-band wavelength, multiple gases can be recorded with the absorption spectra in one sensing operation. As a demonstration, the sensor was tested in NH3 with multiple gases combined, a sensitivity up to 17.3 nW/ppm was achieved. The PCF–LPG-based gas sensors are easy-to-fabricate, cost-effective, and can be used in various applications where conventional fiber-optic sensors are not applicable.

Controlling and geometrical parameters are simultaneously optimized.A two-level bi-coded chromosome is proposed.HGA can avoid premature convergence and converges fast.Proposed FE computation using sparse FE mesh is comparable to available ones. The present paper introduces an investigation into simultaneous optimization of the PbLaZrTi-based actuator configuration and corresponding applied light intensity for morphing beam structural shapes. A finite element formulation for multiphysics analysis of coupled opto-electro-thermo-mechanical fields in PbLaZrTi ceramics is derived and verified with the theoretical solution and the commercial software ANSYS. This element is then used to simulate beam bending shape control using the orthotropic PbLaZrTi actuators and the simultaneous optimization. In this procedure, the controlling and geometrical variables are simultaneously optimized via a hierarchical genetic algorithm. A bi-coded chromosome is proposed in a hierarchical mode, which consists of some control genes (i.e. actuator location and number) and parametric genes (i.e. applied light intensity). Whether the parametric gene is activated or not is managed by the value of the first-grade control genes. The numerical results demonstrate that the achieved beam bending shapes correlate remarkably well with the expected ones and the simultaneous optimization of photostrictive actuator locations, numbers and light intensities can result in optimal actuator layout with less PbLaZrTi actuators and irradiated light energy. The simulation results also show that the hierarchical genetic algorithm has more superior performance over the conventional real-coded genetic algorithm.

Sensitivity of fiber cladding modes coupled with long-period gratings (LPGs) in photonic crystal fiber (PCF) are investigated with respect to external conditions such as temperature, strain, the surrounding refractive index, curvature, and torsion. What we have found is that the application of MODE Solutions to a given PCF structure can produce a large amount of modes, where the dispersion and group velocities are generally a function of wavelength, hence the cladding modes with ultra-sensitive spectrum behavior for LPG coupling and sensing purpose. By means of analyzing equation of phase-matching condition, we can better understand sensitivity characteristics of cladding modes. The results of numerical computation indicate that the maximum or minimum sensitivity of a cladding mode coupled with PCF-LPG is predetermined by its dispersion, which is also influenced by the PCF structure geometry. The design of the structural geometry gives a large degree of freedom with respect to tailoring its optical properties. Multi-parameter sensing is discussed in light of utilizing the resonances at discrete wavelength locations distinguishing and simultaneously measuring two parameters in a PCF-LPG.

A new heuristic strategy for the non-uniform strain profile reconstruction along Fiber Bragg Gratings is proposed in this paper, which is based on the modified transfer matrix and Genetic Programming(GP) algorithm. The present method uses Genetic Programming to determine the applied strain field as a function of position along the fiber length. The structures that undergo adaptation in genetic programming are hierarchical structures which are different from that of conventional genetic algorithm operating on strings. GP regress the strain profile function which matches the ‘measured’ spectrum best and makes space resolution of strain reconstruction arbitrarily high, or even infinite. This paper also presents an experimental verification of the reconstruction of non-homogeneous strain fields using GP. The results are compared with numerical calculations of finite element method. Both the simulation examples and experimental results demonstrate that Genetic Programming can effectively reconstruct continuous profile expression along the whole FBG, and greatly improves its computational efficiency and accuracy.

Effects of methanesulfonic acid (MSA) and aminomethylsulfonic acid (AMSA) as additives for positive electrolyte on thermal stability and electrochemical performance are investigated. Both additives can improve the thermal stability of V(V) electrolyte, and AMSA has better effect, especially. The electrochemical results show that V(IV)/V(V) exhibits superior electrochemical activity and reversibility with additives, and the diffusion coefficient of V(IV) species, exchange current density and reaction rate constant become larger with additives in positive electrolyte. Among the two additives, AMSA has better effect for improvement of electrochemical activity and kinetics. The cell using positive electrolyte with additive of AMSA was assembled and the charge–discharge performance was evaluated. The assembled cell using AMSA as positive electrolyte additive shows good cycling performance, with higher energy efficiency (81.5%) and larger discharge capacity retention (40 cycles: 82.7%). The improved electrochemical performance may be ascribed to more active sites provided by NH2 group and the enhanced hydrophilicity of the electrode provided by NH2 and SO3H groups.

A photonic crystal fiber (PCF) long-period grating (LPG) humidity sensor has been developed with high sensitivity and selectivity for nondestructive detection of moisture ingression into structures that can potentially lead to corrosion. We have proposed two types of nanofilms to be coated on the surface of air channels in the grating region by electrostatic self-assembly deposition processing. The primary nanofilm does not affect LPG properties such as resonance wavelength or transmission intensity which can impact sensing characteristics; however it increases the sensitivity by changing the refractive index of the surrounding material. The secondary nanofilm is used for selectively adsorbing analyte molecules of interest. The experimental results reveal that, compared to the conventional fiber LPGs and exterior nanofilm-coated PCF-LPG, the interior nanofilm-coated PCF-LPG humidity sensors have both the most sensitive resonance intensity change of 0.00022%/10 −3 dBm from relative humidity (RH) of 38% to 39% and average wavelength shift of 0.0007%/pm for a relative humidity variation from 22% to 29%. The proposed sensor shows excellent thermal stability as well.

Nuclear shape coexistence and shape change induced by 1 g 9 / 2 orbitals have been investigated using configuration-constrained potential-energy-surface and Total-Routhian-Surface calculations. Oblate isomeric states and shape-coexisting rotational bands are found and compared with available experimental data. The effects of the 1 g 9 / 2 orbitals on nuclear structure are discussed.

In this paper, a new heuristic approach based on chaos genetic algorithm and modified transfer matrix method is presented to demodulate the fiber Bragg grating strain sensors. To facilitate accurate calculation of the grating reflected intensity spectrum, the modified transfer matrix approach is applied. The motivation for using the spline smooth function scheme is to provide nice approximation of strain profiles from a scattered data set and overcome the difficulty of calculating the strain gradients in local period function of the modified T-matrix formulation for the piecewise constant strain field assumption. The chaos genetic algorithm is developed to improve the performance of GA and optimize the data of control nodes of the spline smooth function, and more valuably, the reconstructed strain profile is continuous with discretionary spatial resolution. The proposed method is verified through numerical example reconstructions of Bragg grating sensor simulated strain profile cases.

A novel special finite element with an elliptical notch, based on the complex potential theory and hybrid variational principle, is proposed for mechanical–electrical coupling analyses of piezoelectric plates with notches. The formulations are given and a variety of examples are analyzed. Comparisons are made with existing analytical or numerical data. It is shown that the proposed element is very efficient and accurate. Some new numerical results are given and discussed. It is found, perhaps for the first time according to the authors’ knowledge, that the relationships between the logarithm concentration factor of tangential ( θ = 0 ) stress, electrical displacement, and electrical field at the notch tip and logarithm b/a are linear. Some conclusions are drawn based on the results reported herein.

In vibration active control of composite structures, piezoelectric sensors/actuators are usually bonded to the surface of a host structure. Debonding of piezoelectric sensors/actuators can result in significant changes to the static and dynamic response. In the present paper, an novel Enhanced Assumed Strain(EAS) piezoelectric solid element formulation is developed for vibration active control of laminated structures bonded with piezoelectric sensors and actuators. Unlike the conventional brick elements, the present formulation is very reliable, more accurate, and computationally efficient and can be used to model the response of shell structures besides thin plates. Delaminations are modeled by pairs of nodes with the same coordinates but different node numbers, and numerical results demonstrate the performance of the element and the global and local effects of debonding sensors/actuators on the dynamics of the adaptive laminates.