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Objective: This study aimed to evaluate the effect of surface texture mold by stainless steel (SS) mesh on Invisalign material friction coefficient. Materials and methods: Ten kinds of SS mesh were used to mold surface texture on Invisalign material. Experiments were conducted using a zirconia ball that slid against Invisalign material plates with different surface textures. In the experiments, the coefficients of friction under normal loads of 100, 200, and 300 g under dry and artificial saliva conditions were recorded. Results: The coefficient of friction was relative to the pore size and wire diameter of SS mesh. Conclusions: The Invisalign material coefficient can be effectively managed by the surface texture mold by SS mesh.

The near-field characteristics of the ideal electric dipole are analyzed in this paper. A practical ultrafast band antenna near field FDTD is made and the near field distribution of the antenna is studied by numerical simulation. The calculation results show that the FDTD method is used for the analysis of feasibility and reliability of the near-field communication antenna.

The short-circuit reactance is an important parameter to characterize the transformer ability to resist the attack of short-circuit current in the design the operation process. In this paper, the on-line measuring method for short-circuit reactance based on electrical parameters' characteristics was presented, and the feasibility to carry out on-line monitoring for the transformer operation condition was also analyzed. Besides, the principle of two on-line measuring methods based on respectively exciting current compensation and elimination technique was researched, and the calculation equations were deduced. The comparison between the on-line results measured from moving mold experiment and those from off-line short-circuit experiment showed that these two methods were accurate and valid.

We herein constructed a sensor that converts T4 DNA ligase-induced conformational transformation of the probe DNA to electrochemical response based on host-guest recognition and nanoparticle label. In the sensor, the hairpin dsDNA terminal-labeled with 4-((4-(dimethylamino)phenyl)azo)benzoic acid (dabcyl) and thiol group was immobilized on Au electrode surface as the probe by Au-S bond, and the CdS nanoparticles surface-modified with β-cyclodextrins (CdS-CD) were employed as electrochemical signal provider and host-guest recognition element. After T4 DNA ligase repairing single-strand breaks in duplex DNA, the dsDNA probe underwent a significant conformational change, which forced dabcyl away from the electrode. As a result, formerly shielded dabcyl became accessible to host-guest recognition between β-cyclodextrin and dabcyl, thus the target repairing event could be sensitively transduced to electrochemical signal provided by CdS-CD.

In the present study, we describe an electrochemical sensor for Hg2+ detection by using the DNA probe. Two specific sequence for the probes, one has to ensure that the probe A hybridized with probe B modified on CdS nanoparticle to form stable DNA duplexes only in the presence of Hg2+ at a given operating temperature. After dissolving the CdS particles from the electrode, a mercury-film electrode was used for electrochemical detection of these Cd2+ ions which offered sensitive electrochemical signal transduction.The limit of detection of this assay in buffer is 12 nM. The detection was also specific for Hg2+ without being affected by the other metal ions, such as Cd2+,Li+,Ba2+,K+,Ca2+.

Automatic leveling system used in railway rescue crane has characteristics such as time variance, nonlinearity and strong interference, which bring a variety of difficulties in control process into existence. This paper introduces the working principle and mathematical model of automatic leveling system used in railway rescue crane. A fuzzy PID controller based on fuzzy logic control algorithm and conventional PID algorithm is designed, MATLAB simulation results show that the effectiveness of the proposed fuzzy PID controller, and the fuzzy PID control strategy has better effect on the automatic leveling system used in railway rescue crane.

For sake of analyzing influence on load characteristic of urban low voltage distribution network from extensive popularization of charging equipments of electric vehicles, this paper establishes probability density distribution load characteristic model of charging equipment. Taking representative distribution lines and transformer areas with residential and commercial users for instance, summer daily load curves are described and charging load are forecasted, and basic load curves and charging load additional demand curves are peak-valley superimposed according to respective traits, further more, the influence on distribution lines and transformer areas from charging load of electric vehicles with different ages, finally, suggestions are put forward of urban low voltage distribution network planning and charging equipment supervisions.

Yb-doped titanium dioxide nanoparticles were synthesized using collagen as the template, and characterized by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-Vis spectrophotometry, and Fourier transform infrared (FT-IR) spectra. The effect of doping concentration and calcination temperature on structure of TiO2was discussed. The results showed the Yb-TiO2nanoparticles have high crystallinity with the size of 18-28 nm. Ytterbium doping could inhibit the phase transformation from anatase to rutile of TiO2, reduce the crystallite size, improve thermal stability, and improve the light absorption. This study indicates that collagen could be used as an ideal biological template to prepare metal oxide nanoparticles with high crystallinity.

Cu/graphene nanosheets composites were fabricated at 800°C by the hot-pressing method using Cu and graphene as initial materials. Graphene content was 1 wt. %-5 wt. %. The fracture morphology and physical properties of the composites were investigated. It was found that the relative density increased with the increment of graphene content from 1 wt% to 5 wt. % with reaching its highest level (96.68%) at 5wt. %. The composites have the anisotropic property which is vertical to the direction of pressure is higher than parallel to the direction of pressure. With the increasing of graphene content, the thermal conductivity property and the electronic conductivity decrease first and then increase with the minimum thermal conductivity and electric conductivity at 3wt%~4wt%.

In this paper use the shield construction of Dalian subway 202 bid section as an example, carried out the monitoring measurement of surface subsidence and crown surface subsidence during the shield construction, detailed analysis the monitoring data, explored the characteristics and distribution of surrounding rock and surface deformation of large cross section shield construction. Construction transverse deformation has a relationship with lateral position and the tunnel excavation length. The closer from shield machine working face, the closer to the center line of the tunnel, the greater impact is. The research results have reference value for the future similar engineering design and construction.

Live migration provides desirable benefits in the field of energy saving, which packs service into fewer physical servers while maintaining the performance level. In this paper we present energy guided and workload adaptive modeling for live migration, two models are developed respectively including energy guided migration model and workload adaptive model, the former model selects the best migrating virtual machine (VM) candidate with the minimal energy consumption while the later model chooses the best migrated physical server candidate in terms of both energy and workload characteristics, furthermore, concerning the service quality, workload adaptive model also takes charge of the determination of the live migration moment. The experiments results show that our approach achieves significant energy saving and robust live migration.

This paper presents a new system for rapidly acquiring stereo images using a single camera and a pair of planar mirrors (catadioptric stereo). Firstly, the camera used to capture images is calibrated with matlab toolbox. Secondly, the position and pose of the planar mirrors relative to the fixed, calibrated camera is estimated, and this procedure is accomplished by calculating the symmetry plane of the real and reflected image corners of a chessboard. Thirdly, the relative orientation of two reflected virtual cameras is obtained. Finally, Gaussian noise is added to the image corners of the chessboard to verify the performance of the established stereo system. Experimental results show the effectiveness and robustness of our system.

A monitoring system was implemented to monitor the hydrodynamic and deformation response of a preexisting landslide in the Three Gorges Reservoir area. The monitoring results indicate that the deformation is mainly caused by reservoir impounding and is mainly composed of the deformation of the slip band. The effect of reservoir level fluctuation on landslide stability mainly depend on two aspects, one is the change of shear stress and shear strength on the slip surface due to the change of slide body weight and pore water pressure, the other is seepage pressure.

A new detection method of weak signal mixed in strong noise is proposed. The method includes theory scheme, hardware and software. It detects and processes signal by using the instrument magnifying technology and single-chip microcomputer control. By means of virtual instrumentation simulation and display, this design provides effective methods to detect µA-level weak signal in piezoelectric infrared detector. Through the experiment of simulate low frequency weak signal detection, the system fully reveals its practicality and superiority in the field of lower S/N signal detection.

Owing to several construction procedures of bidirectional 6 lane multi-arch tunnel, with the characteristics of large dig span and flat cross section, the wall rock and support structure of which will be repeatedly disturbed by multiple excavations, so their mechanical and deformational features are remarkably complicated. Combined with the design and construction practice of Sha Tangkeng bidirectional 6 lane multi-arch tunnel of Guang-He highway, taking the V grade surrounding rock for case, with the help of 3-dimension finite element numerical simulation method and 3-dimension physical similar model test, the paper studied the entire dynamic construction process of bidirectional 6 lane multi-arch tunnel, analyzed the chang characteristics of displacement and stress of wall rock and stress of supporting structure, and revealed the time-space effect laws of construction of bidirectional 6 lane multi-arch tunnel.

The method of piston pin's strength calculation base on FEA is proposed to solve the pin's failure. The pin's circular deformation is measured by node displacements, and the conventional static strength analysis is replaced by multi-case fatigue calculation. Compared with the conventional strength verification method, the FEA result is more accurate with the reality.

Aiming at filling the holes which were generated from uncompleted point cloud data in reverse engineering, a new hole filling algorithm in space is presented. Firstly, the holes boundary was identified and pretreated, and the hole boundary feature datum was established and the boundary was projected on it to form a projection polygon. Secondly, the smallest angle of the projection polygon was found out to determine the corresponding boundary point as the mesh growing point. The original hole was covered by the new meshes covering and then filling algorithm was completed. Finally, the neighborhood points of hole boundary vertex were selected as the sampling points for the least squares fitting adjustment of new filled vertices position, which aims at the preparation hole filled result. Examples are given to prove that the method has good accuracy and stability of the hole filling.

Neighborhood tunnel is a special structural type with a clear distance between multi-arch tunnel and usual separated tunnel’s minimum required in the tunnel design regulations. The clear distance is small, so the interaction of two tunnels is relatively great, which will greatly influence the stability of surrounding rock especially interlaid rock. Therefore, it is very necessary to seek a safe, convenient and economical excavation method for neighborhood tunnel. Combining with an expressway neighborhood tunnel engineering practice (with clear distance 4.0m, buried depth 30.0m) withⅡ-class surrounding rock and by three-dimension elastic-plastic element numerical simulation, this paper analyzed the surrounding rock destruction approaching degree and deformation characteristics separately according to cheek pilot method, combination method, and up-down bench method of double tunnel. On the basis of the analysis, this text studies advantages, disadvantages and adaptability of each of the three different excavation methods, to provide scientific reference for design and construction of freeway neighborhood tunnel.

The elastic-plasticity of ten cross-section reinforced-concrete short-limb shear wall specimens under monotonic load are analyzed by ANSYS, which compares the change of load capacity, stiffness and ductility of the shear wall when concrete strength grade and limb-length ratio change. The analysis results show that when concrete strength grade is C30, shear wall of this shape can be made with better performances in load capacity and deformation capacity, and when limb-length ratio is 0.6, the ductility and the ability of the energy dissipation of shear wall is not good, which provides a significant basis for practical engineering section design.

A group of geometrically similar elements is automatically generated layer by layer around the tip of crack. By taking advantage of the same stiffness and similar mass of similarly shaped elements, the combined stiffness matrix and combined inertia matrix in area can be expressed by the displacement row matrix of outer polygon. The global stiffness matrix will be obtained if the combined stiffness matrix and combined inertia matrix of area are assembled to those of another elements according to corresponding nodes. The small set of generalized coordinates can be obtained through solving the equation, and then the dynamic stress intensity factor of crack will be obtained. The three points bending with single crack and shearing model with double cracks in explosive loading were calculated with finite geometrically similar element method.