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Considering that diaphragm spring is the core component of the mechanical clutch, the optimization to which plays practical roles in engineering practices, the multi-objective optimization model for the diaphragm spring of the clutch is established in this article. Aiming at the difficulty in local extremum due to pre-maturity of inertia weight and treatment on nonlinear constraint condition of standard particle swarm optimization (PSO), the improved particle swarm algorithm（Improved PSO） based on dynamic weight and hierarchical penalty function in consideration of the degree of congestion is proposed in this article to improve the original particle swarm algorithm. According to the results of calculating examples, the improved particle swarm algorithm can achieve better global searching ability and convergence ability; when compared with the calculating results of the penalty function algorithm, the genetic algorithm and the NSGA-II algorithm, the pressing force of the diaphragm spring with the new algorithm is increased by 3.24%, and the steering separation force is decreased by 20.09%. The diaphragm spring has better pressing force stability and operating lightness, verifying the correctness of the model and the algorithm proposed in this article.

This paper is concerned with the dynamic response of straddle-monorail with single-axle bogie under curve condition. A 15 degrees-of-freedom(DOF) dynamic model is established for straddle-type monorail vehicle with single-axle bogie, which consists driving wheels, steering wheels and stabilizing wheels. The motion equations of the straddle-type monorail vehicle are derived using the Lagrange's equation, and the wheel-rail contact model and the curving track beam model are created. Compared with the test results, the accuracy of the method is verified. Finally, the influence of curve radius, curve superelevation rate, number of passengers and stiffness of driving wheels on dynamic response is discussed.

In order to improve the ride comfort straddle-type monorail, based on the full-scale straddle-type monorail model with 38-DOF, combined with the modular control thought and adaptive neural fuzzy inference system(ANFIS) control theory, the ANFIS-PID controller is designed, in which the vertical vibration velocity and acceleration, pitching angular velocity and angular acceleration, rolling angular velocity and angular acceleration are taken as inputs and the actuator force of active suspension as outputs. The results show that compared with existing passive suspension, the root mean squared values(RMS) of vertical acceleration, pitching angular acceleration and rolling angular acceleration of active suspension is significantly reduced, respectively. And the vibration amplitude below 10Hz frequency range is suppressed, which is the human sensitivity frequency. Active suspension controlled by ANFIS-PID can be used as a way to improve the ride comfort of straddle monorail vehicles.

In order to study the vertical dynamic behavior of the monorail-bridge system, the vehicle-bridge coupling dynamic equation and train simulation model are established based on the principle of dynamics; the train simulation model is established based on the multi-body dynamics; the track model is established based on the finite element theory, and the compression deformation of PC beam and the effect of finger band on train are equivalent to load spectrum on train axle by means of dynamic equivalence principle, and finally, the train-track interaction model is established; the vertical vibration of the train before and after adding the influence of the compressive deformation of the track beam is simulated and calculated respectively, the results show that the influence of the compressive deformation of the track beam on the vertical vibration of the train is significant, and the simulation data under multiple road excitations are very close to the real value.

By permutation behavior of certain linearized polynomials, the bentness of quadratic vectorial bent functions of the form F (x)=+Trmkt(ckx1+2kt) is investigated, where n=2kt and m|kt with k, t being positive integers. The numerical results show that there exist new quadratic vectorial bent functions obtained up to extended affine equivalence

This article focus on the dynamic behavior of straddle-type monorail composed of multiple vehicles. The four-vehicle dynamic model of straddle-type monorail considering the coupler force is established on the basis of the coupler dynamic model. The correctness of the model is verified by the real experimental vehicle test of Chongqing straddle monorail line 3 from Huixing station to Changfuroad station. The stable wheel overturning coefficient suitable for monorail is proposed which is used to evaluate the anti-overturning performance of straddle monorail. The vibration response, riding comfort, and dynamic curving behavior are analyzed using the dynamic model. The results show that the vibration response of car body accelerations obtained by single-car model is much different from that obtained by train model. The riding comfort of straddle-type calculated by the single-car model would make large mistake, and a multiple train model is needed. The dynamic curving behavior of straddle-type monorail obtained by the single-car model could represent the dynamic curving behavior well.

Based on the Lagrange equation, the linear and nonlinear dynamic models of straddle monorail pantograph considering the lateral vibration of bogie are derived. On this basis, the lateral coupling dynamic model of pantograph-catenary is established. Newmark method is used to solve the pantograph-catenary coupling dynamic model. In order to evaluate the applicability of the two models，this paper analyzed the contact force response of two model with different speeds. The reasearch show that when the speed is below 40 km/h, the contact forces of nonlinear model and linear model can reflects the lateral excitation of the finger plate. When the speed exceeds 40 km/h, only the nonlinear model can reflect the lateral excitation of finger palte, the nonlinear pantograph-catenary coupling dynamics model is more suitable to the straddle-type monorail pantograph-catenary coupling research.

Mid-infrared (mid-IR) sensors consisting of silicon nitride (SiN) waveguides were designed and tested to detect volatile organic compounds (VOCs). SiN thin films, prepared by low-pressure chemical vapor deposition (LPCVD), have a broad mid-IR transparent region and a lower refractive index (nSiN = 2.0) than conventional materials such as Si (nSi = 3.4), which leads to a stronger evanescent wave and therefore higher sensitivity, as confirmed by a finite-difference eigenmode (FDE) calculation. Further, in-situ monitoring of three VOCs (acetone, ethanol, and isoprene) was experimentally demonstrated through characteristic absorption measurements at wavelengths λ = 3.0–3.6 μm. The SiN waveguide showed a five-fold sensitivity improvement over the Si waveguide due to its stronger evanescent field. To our knowledge, this is the first time SiN waveguides are used to perform on-chip mid-IR spectral measurements for VOC detection. Thus, the developed waveguide sensor has the potential to be used as a compact device module capable of monitoring multiple gaseous analytes for health, agricultural and environmental applications.

Tunable photonic circuits were demonstrated in the mid-Infrared (mid-IR) regime using integrated TiO2-on-LiNbO3 (ToL) waveguides. The upper waveguide ridge was made by a sputtered TiO2 thin film with broad transparency at λ = 0.4–8 µm and an optimized refractive index n = 2.39. The waveguide substrate is a z-cut single crystalline LiNbO3 (LN) wafer that has strong Pockels effect, thus enabling the tunability of the device through electro-optical (E-O) modulation. A sharp waveguide mode was obtained at λ = 2.5 µm without scattering or mode distortion found. The measured E-O coefficient γeff was 5.9 pm/V approaching γ31 of 8.6 pm/V of LN. The ToL waveguide showed a hybrid mode profile where its optical field can be modified by adjusting the TiO2 ridge height. Our monolithically integrated ToL modulator is an efficient and small footprint optical switch critical for the development of reconfigurable photonic chips.

The dynamic parameters of Straddle-type monorail vehicles with single-axle bogies are optimised by utilising the multi-body dynamic method. The dynamic parameter optimisation is conducted a...

The longitudinal drawbar and the lateral stabilizer bar of straddle-type monorail vehicle with the single-axle bogies have relatively long structure size. The multibar system leads to deformation during the driving process due to impact loads, even leads to influence on the dynamic characteristic of the hauling mechanism as well as the riding comfort of the whole vehicle. To evaluate the dynamic behavior of straddle-type monorail vehicle with single-axle bogies accurately, a full-scale rigid-flexible coupling multibody dynamics method is proposed based on multibody dynamics and finite element (FE) theory. The modal synthesis method is adopted to establish flexible multibody dynamics of the single-axle bogies. And then rigid-flexible coupling dynamic model of the straddle-type monorail vehicle is established with the ADAMS software. The validity of the full-scale model is verified. Finally, the influences of vehicle velocity, passenger mass, curve radius and the number of axles on dynamic characteristics are discussed.

To address multiobjective, multi constraint and time-consuming structural optimization problems in a vehicle axle system, a multiobjective cooperative optimization model of a vehicle axle structure...

This work focuses on the development of nanoparticle-based layer-by-layer (LbL) coatings for enhancing the detection sensitivity and selectivity of volatile organic compounds (VOCs) using on-chip mid-infrared (MIR) waveguides (WGs). First, we demonstrate construction of conformal coatings of polymer/mesoporous silica nanoparticles (MSNs) on the surface of Si-based WGs using the LbL technique and evaluate the coating deposition conditions, such as pH and substrate withdrawal speed, on the thickness and homogeneity of the assemblies. We then use the modified WGs to achieve enhanced sensitivity and selectivity of polar organic compounds, such as ethanol, versus non-polar ones, such as methane, in the MIR region. In addition, using density functional theory calculations, we show that such an improvement in sensing performance is achieved due to preferential adsorption of ethanol molecules within MSNs in the vicinity of the WG evanescent field.

A chip-scale mid-infrared (mid-IR) sensor was developed for hydrocarbon gas detection. The sensor consisted of amorphous Si (a-Si) optical ridge waveguides that were fabricated by complementary metal–oxide–semiconductor (CMOS) processes. The waveguide exhibited a sharp fundamental mode through λ = 2.70 to 3.50 μm. Its sensing performance was characterized by measuring methane and acetylene. From the spectral mode attenuation, the characteristic C–H absorption bands associated with methane and acetylene were found at λ = 3.29–3.33 μm and λ = 3.00–3.06 μm, respectively. In addition, real-time methane and acetylene concentration monitoring was demonstrated at λ = 3.02 and 3.32 μm. Hence, the mid-IR waveguide sensor enabled an accurate and instantaneous analysis of hydrocarbon gas mixtures.

A real-time, nondestructive mid-infrared (mid-IR) platform was proposed for isotopic methane detection. The measurement system consisted of a tunable mid-IR laser, a miniaturized gas chamber, and a mid-IR signal receiver. The isotope ratio of the 12 C H 4 / 13 C H 4 was identified by measuring the mid-IR spectrum at λ = 3 . 2 − 3 . 5 µ m . In-situ 12 C H 4 / 13 C H 4 monitoring was then achieved by tracing the characteristic mid-IR absorption peaks assigned to the 12 C H 4 at λ = 3.328 µ m and 13 C H 4 at λ = 3.340 µ m . The real-time methane isotope analysis can be applied to environmental monitoring and petroleum industries.

Broadband mid-infrared (mid-IR) frequency doubling was demonstrated using nonlinear barium titanate (BTO) thin films. The device has a strip-loaded waveguide structure consisting of top silicon nitride (SiN) strips and an underneath BTO guiding layer. The epitaxial BTO was deposited on a strontium titanate (STO) substrate by pulsed-laser deposition. Through a SiN grating coupler, the pumping mid-IR light at wavelength λ = 3.30 − 3.45 µ m was coupled into the nonlinear BTO layer, where the spectrum of the near-infrared (NIR) second-harmonic generation was characterized. The developed BTO waveguides provide a platform for mid-IR nonlinear integrated photonics and on-chip quantum optics.

Functionalization of optical waveguides with submicron coatings of zinc peroxide (ZnO2) and silica (SiO2) nanoparticles (NPs) is reported that enabled selective concentration of acetone vapors in the vicinity of the waveguide, boosting the sensitivity of a mid infrared (MIR) on-chip detector. Controlled thickness was achieved by introducing precise control of the substrate withdrawal speed to the layer-by-layer (LbL) deposition technique.

In this paper, based on the theory of \begin{document}$ \mathbb{Z}_{4} $\end{document}-valued quadratic forms we propose several classes of generalized Boolean bent functions over \begin{document}$ \mathbb{Z}_{4} $\end{document}, and new families of codebooks are constructed from these functions. The codebooks constructed in this paper are nearly optimal with respect to the Welch bound, and their parameters are new. Furthermore, some Boolean bent functions are also derived.

In situ material identification and object tracking have been demonstrated using a mid-infrared (mid-IR) robotic scanning system. This detection method is capable of inspecting materials noninvasively because the mid-IR spectrum overlaps with numerous characteristic absorption bands corresponding to various chemical function groups. The scanning system consisted of a fiber probe connected to a mid-IR tunable laser with a wavelength tuning range of λ = 2.45-3.75 μm. For the high-speed performance of the scanning system to be evaluated, a testing platform was constructed with an object plate rapidly rotating at ω = 231 rpm. The objects on the plate were SU-8 epoxy-based resin and polydimethylsiloxane, which were mid-IR absorptive while visibly transparent. Applying mid-IR multispectral scanning, the system was able to simultaneously track the object position and identify the composition by interpreting the spectral and spatial intensity variation. The mid-IR robotic scanning method thus provides a visualization system critical for process inspection in automatic manufacturing and high-throughput biomedical screening.

Local hydrodynamics of a gas–liquid–solid system, such as bubble circulation regime, gas holdup, liquid velocity and axial profile of solid concentration, are studied in a two-stage internal loop airlift reactor. Empirical correlations for gas holdup and liquid velocity are proposed to ease the reactor design and scale-up. Different bubble circulation regimes were displayed in the first (lower) and second (upper) stages. Increasing superficial gas velocity and solid loading can promote regime transition of the second stage, and the gas holdup of the second stage is higher than that of the lower stage. In addition, the effects of solid loading on bubble behaviour are experimentally investigated for each stage. It is found that bubble size in the downcomer decreases with the presence of solid particles, and bubble size distribution widens under higher superficial gas velocity and lower solid loading.

In order to master the main malfunction and the law of occurrence of the vehicle which affects the operational reliability of the Straddle-Type Monorail traffic, this paper, based on the structural characteristics of monorail vehicle system and the statistical data of vehicle operational malfunction, uses the analysis method of system reliability engineering to study and determine the key factors that affect the operational reliability of monorail vehicle. Then, the operational reliability evaluation index system of monorail vehicle is established based on the influencing factors. Finally, the AHP (Analytic Hierarchy Process) method is used to determine the weights of each index, and the fuzzy comprehensive evaluation method is used to evaluate the operational reliability of monorail vehicle synthetically. The evaluation results have some guidance on the development of more effective maintenance strategies for monorail vehicle maintenance departments.

Optical waveguides using a visible transparent nitride were developed to perform fluorescence measurement on a chip. Through finite difference time domain (FDTD) design, the exciting green light was guided by the micron-scale ridge waveguide, while its evanescent wave was expanded outside the waveguide surface and capable to efficiently excite the fluorescent molecules that were approaching the waveguide facets. Since the waveguide was centimeters long, it has a longer fluorescence excitation path comparing to traditional samples prepared for microscopy measurements. As result, the waveguide device can excite stronger fluorescent signals. In addition, the nitride waveguide was prepared by the complementary metal–oxide–semiconductor (CMOS) process thus enabling high volume manufacturing and reducing the cost of the device fabrication. The AlN waveguide was then integrated with a microfluidic devices to experimentally demonstrate real-time fluorescence detection. Solution samples with different dye concentrations were sequentially injected into the microfluidic chamber. By recording the emission signals, we showed that the fluorescent signals were consistently amplified as the dye concentrations increased. In addition, real-time fluorescence detection with a response time less than seconds was achieved. The developed waveguide based fluorescence measurement provides a new miniaturized platform for low cost and highly accurate point-of-care application.

Tunable photonic circuits were demonstrated by using ferroelectrics that had large electro-optic effect. The photonic circuits were fabricated by complementary metal–oxide–semiconductor (CMOS) technology thus enabling their integration with the present microelectronics for high speed signal modulation. From the scanning electron microscopy and energy-dispersive X-ray spectroscopy, we showed the photonic devices, including the optical waveguides, had sharp waveguide edges and interfaces. A sharp fundamental waveguide mode was observed over a broad spectral range. Tunability using Pockels effect were experimental results. Our device paves the way for ultra broadband integrated photonics critical for optical computing.

The tensorial second order optical nonlinearity of the epitaxial barium titanate (BaTiO3) thin films was characterized by second harmonic generation (SHG). The thin film was prepared by pulsed laser deposition (PLD). From the azimuthal-dependent SHG intensity, the ferroelectric a/c domain fraction ratio was resolved. The high second order optical nonlinearity enables (BaTiOs) thin film for applications in nonlinear integrated photonics.

Miniaturized mid-Infrared (mid-IR) photonic sensors were utilized for volatile organic compounds (VOCs) detection. The optical waveguides were fabricated by microelectronic processes.

Miniaturized photonic sensors were demonstrated using mechanical bendable aluminum nitride waveguides. The sensor is bendable because it has a thickness less than 30µm that significantly decreases the strain.

A mid-infrared (mid-IR) sensor chip was demonstrated for volatile organic compound (VOC) detection. The sensor consisted of As2Se3 optical waveguides built by microelectronic fabrication processes....

Vortex beams were theoretically demonstrated by patterning a fiber facet with N -segment microphase plates. By changing the aluminum oxynitride material composition of each segment, gradient refractive-index phase plates (GRPs) were designed and introduced a 2 π l azimuthal optical phase difference. The gradient index profile was able to convert a fiber Gaussian mode to a Laguerre–Gaussian mode with varieties of topological charge l . A three-dimensional finite-difference time-domain method was applied to calculate the near-field optical phase maps and the far-field beam profiles projected from the micro-GRPs. A uniform vortex beam with a symmetrical doughnut shape was obtained by optimizing the GRPs’ radii and the number of segments. The micro-GRPs enabled flat optical components for efficient vortex beam generation.