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The static and quasi-static behaviors of cast-in-place pier and grouted sleeve connected precast pier are simulated by ABAQUS, which are based on the steel hysteretic constitutive model. The accuracy of the finite element simulation is verified by comparing with the existing experimental results. Then the simulation results of the two types of piers are compared and analyzed. The results show that: the seismic performance of precast pier connected with grouting sleeve is similar to that of cast-in-place pier, they both have good plastic deformation capacity. When the displacement is large, grouting sleeve connected pier has higher hysteretic energy dissipation than that of cast-in-place pier, it’s suitable in high earthquake region; The steel hysteretic model can better simulate the seismic performance of reinforced concrete structure under cycle load.

a coupled numerical method (FEM/DEM) is generated to model the complete fracture processes of rock material. cohesive elements are inserted along the boundaries of the discretized elements to model the fracture initiation and propagation in rock material. Then this method is applied to the jointed slope, and the stability of the slope under different joint cohesion is studied. By comparing theoretical values and numerical results, it is verified that this numerical method can effectively and reliably study the stability of jointed slopes.

The improved genetic algorithm is combined into the foundation pit finite element method. On the basis of the measured lateral displacement data on site, the parameters of the foundation soils were obtained by the back analysis. Then the lateral deformation of the surrounding soil was analyzed on the condition of each different step under the foundation pit excavation according to the inversion parameters, and the calculation and analysis of lateral displacement of cement-soil pile with anchorage retaining structure was did. The results reveal that the calculated value is agreed with to the measured value, which indicates that the improved genetic algorithm is efficient to the related constructions.

A flexible and wearable thermoelectric wristband consisting of a poly(3,4-ethylenedioxythiophene):p-toluenesulfonic acid (PEDOT:Tos)-coated nanofibrous film (P-type legs) and a Ag nanoparticle-coated nanofibrous film (N-type legs) is constructed to realize the thermoelectric conversion by harvesting of the human body heat. Here, P-type legs are prepared via low-temperature in-situ interfacial polymerization, and a coral-like structure is formed on nanofiber. The resultant P-type leg exhibits a high electrical conductivity of 24.50 S cm−1 and a Seebeck coefficient of 13.67 μV K−1 at a temperature difference (ΔT) of 30 °C. Meanwhile, the N-type legs are fabricated via facile wet electroless deposition exhibits an electrical conductivity of 100 S cm−1. Thus, the constructed fiber-based wristband comprises of seven pairs of P-N legs, and can generate a maximum voltage of ∼0.18 mV at ΔT = 10 °C between user’s skin and the environment. Meanwhile, power is up to 101.51 pW after swinging the arm for 5 min. This thermoelectric wristband successfully completes the recycling of the human body heat and provides a new strategy for developing textile-based thermoelectric devices and monitoring human intelligence.

Image processing is to transform the image into digital matrix by mathematical formula, then store the data in the computer, and enhance the source bitmap by computer, including gray-scale processing, median filtering and binarization. Then the image is cut, including contour edge processing, seed filling and so on. In this paper, the image is recognized and processed based on pattern recognition, and then a pre classifier is designed to build a system model of fruit intelligent classification. After the fruit is taken by industrial camera, the corresponding image processing and feature value extraction are carried out. Then the extracted eigenvalues are used for classification. Through this method to achieve a variety of fruit classification effect.

The acceleration control law based on the rotor acceleration N-Dot has been widely applied in the design of aero-engine control systems, especially in the design of transient control law. Its advantage lies in the fact that it can guarantee the consistency of the acceleration performance of engine, not affected by engine manufacturing error, component performance degradation, and so on so forth. During the development of full authority electronic control system (FADEC) for an auxiliary power unit (APU), an acceleration control law is designed based on N-Dot and corrected with turbine inlet gas temperature for APU. The modified N-Dot acceleration control law is verified through rig test and the results show that the designed control system by integrating the modified N-Dot acceleration control law with the limit protection control can effectively prevent the engine from surge and over-speed during the acceleration process, and fully take advantage of the acceleration performance of the engine.

The arrangement of sensors is one of the key points in health monitoring of long-span bridge structures. In this paper, eight algorithms are applied to the optimal sensor arrangement of a long-span cable-stayed bridge and compared. Firstly, eight algorithms and four criteria are introduced, then eight algorithms are applied to optimize the layout scheme, finally, four criteria are used to evaluate the algorithms comprehensively according to the same weight. The results show that in the optimal arrangement of sensor measuring points, it is necessary to combine the engineering practice, comprehensively consider the weight ratio of different criteria, and choose the best optimization scheme.

When solving bridge optimization problems by traditional genetic algorithms, a random method is often used to generate the initial population, which can’t ensure that the initial population is evenly distributed in the solution space and reasonably represents the solution space. In order to solve the shortcomings of random method, an improved population initialization method is proposed by combining random method with good point set. Based on it, aimed at the characteristic of implicit non-linear objective function or constraint function in bridge structure optimization, a BP neural network is used to simulate the relations between the objective function or constraint function and design variables. Then this paper takes a steel truss bridge as an example of optimization. Taken the allowable deflection of bridges as limit and aiming at minimizing the amount of steel, optimization model of bridge is established. Finally, the improved population initialization method is applied to solve the optimization model. The results show that the improved population initialization method can not only improve the uniformity of the population, but also be suitable for optimization design of bridges.

Expansive soil is used as a high-plastic clay, the bearing capacity is gradually attenuated due to the penetration of water, which greatly limits the application range of practical engineering. In this paper, the permeability and expansibility test of remolded soil and undisturbed soil in expansive soil were carried out. Ability coefficient of remolded soil and undisturbed soil under different overburden values was compared and analyzed. Overburden load, head height and water content were studied. The effect of the rate on the permeability coefficient of remolded soil and further analysis of the expansion and expansion forces at different initial moisture contents The results show that the permeability coefficient of remolded soil and undisturbed soil decreases with the increase of overlying load. As the water content increases, the permeability coefficient decreases first within a certain range. After reaching a certain level, the permeability coefficient gradually increases. As the initial water content increases, the amount of expansion progressive decreases and the expansion force progressive decreases.

High-precision displacement sensors, which can measure large displacements with nanometer resolution, are key components in many ultra-precision fabrication machines. In this paper, a new capacitive nanometer displacement sensor with differential sensing structure is proposed for long-range linear displacement measurements based on an approach denoted time grating. Analytical models established using electric field coupling theory and an area integral method indicate that common-mode interference will result in a first-harmonic error in the measurement results. To reduce the common-mode interference, the proposed sensor design employs a differential sensing structure, which adopts a second group of induction electrodes spatially separated from the first group of induction electrodes by a half-pitch length. Experimental results based on a prototype sensor demonstrate that the measurement accuracy and the stability of the sensor are substantially improved after adopting the differential sensing structure. Finally, a prototype sensor achieves a measurement accuracy of ±200 nm over the full 200 mm measurement range of the sensor.

In this study, we investigate the mechanical properties of single-crystal copper (Cu) nanopillars. Critical deformation variations of Cu-nanopillared structures are estimated using in situ transmission electron microscopy compression tests and molecular dynamics simulations. The Young's moduli of Cu nanopillars with diameters of 2–6 nm were 90.20–124.47 GPa. The contact stiffnesses of the Cu nanopillars with diameters of 400 and 500 nm were 1.33 and 3.86 N m−1, respectively; the Poisson's ratios for these nanopillars were 0.32 and 0.33. The yield strength of the nanopillars varied from 0.25 GPa at 500 nm to 0.42 GPa at 400 nm; the yield strength of single-crystal Cu nanopillars decreased with increasing diameter. The values of the indented hardness of the Cu block were 0.27 and 1.06 GPa, respectively. Through experimental work and molecular dynamics simulations, we demonstrate that Cu nanopillars exhibit internal stress transmission during compression. When compression reaches the maximum strain, it can be observed that Cu slips. Our results are useful for understanding the mechanical properties, contact, and local deformation of Cu nanopillars.

The mechanical properties and deformation mechanism of alumina (Al2O3) ceramic nanopillars and microstructures have been studied using in situ transmission electron microscopy (TEM) compression and nanoindentation experiments. It has been found that the Young's modulus of Al2O3 nanopillars significantly increases with a decrease of its thickness; it ranges from 54.8 GPa for the nanopillar of radius 175 nm to 347.5 GPa for the one of radius of 75 nm. The hardness of Al2O3 microstructures estimated by the nanoindentation is between 3.19 to 20.60 GPa. The Raman spectra of Al2O3 substrate has a production peak (577.3 cm−1) between 418.3 and 645.2 (cm−1) peaks. The strain hardening behavior of Al2O3 microstructures has been observed and the impact of size on the compressive and bending behavior of Al2O3 micro-pillared structures is also examined and explained.

Various kinds of fringe order errors may occur in the absolute phase maps recovered with multi-spatial-frequency fringe projections. In existing methods, multiple successive pixels corrupted by fringe order errors are detected and corrected pixel-by-pixel with repeating searches, which is inefficient for applications. To improve the efficiency of multiple successive fringe order corrections, in this paper we propose a method to simplify the error detection and correction by the stepwise increasing property of fringe order. In the proposed method, the numbers of pixels in each step are estimated to find the possible true fringe order values, repeating the search in detecting multiple successive errors can be avoided for efficient error correction. The effectiveness of our proposed method is validated by experimental results.

In order to characterize the torsional behavior of micron-scale specimens, a direct technique is established based on the principle of torsion balance. The technique applies twist to the specimen and balances the resulting torque against a torsion wire of known torsional rigidity. The torsional rigidity of the torsion wire is determined by a torsion pendulum. To measure the rotation of the torsion wire, a sensitive angle detector, comprising a thin cross-beam attached between the torsion wire and the fiber specimen and a laser displacement sensor, is developed. The presented technique permits the measurement of torque in single fibers as low as 10−9 Nm with a reasonable resolution. Using this technique, torsion tests on micro-diameter copper wires, silver wires and carbon fibers were performed. The longitudinal shear modulus and other torsional properties of these samples, such as yielding shear strength, were obtained.