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Aims: (1) Quantitatively characterize the Pseudo Fibrosis Burden (PFB) of Left Atrial Appendage (LAA) Trabecular Musculi Pectinati (TMP) in patients with atrial fibrillation based on histological analysis; (2) Explore the passive dynamic properties of LAA TMP based on uniaxial tensile experiments and determine the hyperelastic constitutive parameters; (3) Explore samples Effects of different storage conditions on the mechanical properties of left atrial appendage TMP. Methods: Fifty TMP were isolated from the resected LAAs of 21 patients with atrial fibrillation and stored (23 strips in the -78°C cryopreservation group and 27 strips in the 4°C normal temperature storage group). The TMP stress-strain curve was obtained through uniaxial tension. According to this curve, the elastic modulus of the low strain zone (EMLS) and the high strain zone (EMHS) were respectively defined. The correlation between the TMP’s diameter and its mechanical properties and the impact of storage temperature on TMP mechanics were analyzed. Four strain energy functions were used to fit the TMP stress-strain curve to obtain the hyperelastic model constitutive parameters. Histological analysis of the axial and transverse microstructure of TMP was performed using Verhoeff-Van Gieson double staining method of Elastic fibers and collagen fibers (EVG) and Masson staining respectively, and the Pseudo Fiber Burden (PFB) was calculated. Analyze the correlation between mechanical properties and PFB. Results: Cryopreservation reduced the elastic modulus in the hyperelastic stage of TMP mechanical properties. EMLS (r=-0.7228, P

In the face of ever-growing and complex massive multi-source spatiotemporal data, the traditional vector data model is increasingly difficult to meet the needs of efficient data organization, management, calculation and analysis. Based on the simple and widely used geographic grid data organization model, this paper designs a technical method to convert vector data into multi-scale grid data, establishes a unified, standardized and seamless land spatial grid data model, and analyses the area accuracy of multi-scale grid data. Practice shows that the model can better meet the needs of multi-scale geospatial information integration and analysis, and it is easy to carry out distributed data processing, which provides technical support for the efficient organization, fusion and analysis of spatiotemporal data.

As one of the important components of the joint connection in the steel-concrete structure, the embedded parts of straight anchors have a great influence on the safety performance of the structure. People have different opinions on the mechanism of the force of the embedded parts, and the calculation method of the bearing capacity of the embedded parts is also different. In this paper, the research on the theory of the sheared and tension-sheared parts of embedded parts of straight anchors in the previous literature and the current norms is conducted, and the existing calculation methods of the ultimate bearing capacity are compared. The calculation method is compared with the experimental results, and the theoretical verification analysis is performed. The research results show that: Nowadays, the calculation of the shear capacity of the anchored parts of the anchors is conservative, and there are some factors that have not been considered, so they are much smaller than the actual bearing values. For the shearing ability, the two are the calculated values whcih are close to the correlation between the pulling and shearing. When the embedded parts are damaged, the anchors fully give full play to the tension-shear effect, which can be used in the project.

A novel wall-climbing robot for the onsite weld inspecting of spherical tank with Time of Flight Diffraction (TOFD) method has been developed, in order to liberate operators from dangerous and heavy working environment. Patented non-contacted permanent magnetic absorbed technology was adopted to realize reliable and flexible all-position moving along the weld seam on the surface of spherical tank. To ensure stable coupling for TOFD test, a surface adaptive probe holder which can provide constant contact force, have been particularly designed. Equipped with a visual sensing based weld seam tracking unit and industrial PC station, the robot could perform automatic flaw detection remotely even in the darkness environment. Onsite ultrasonic weld inspections have been carried out on a 4000m3 spherical tank with 28mm in thickness. It is verified that the robot could accomplish tasks in any position and the acquired TOFD images satisfy the requirements of engineering evaluation.

A single-POF model of disc cutter with rock and soil has been established according to the dynamical feature and vibration mechanism of disc cutter vibro-cutting rock to solve problem of self-adaption vibro-cutting rock for disc cutter, and identification on rock and soil parameter of disc cutter vibro-cutting rock has been carried out by using fuzzy radial basis function neural network. The experimental result of identification simulation and resonant-column test showed that compared to inherent frequency of a hard sandy which was tested by resonant-column test method, the relevant error of rock and soil parameter identification value of disc cutter vibro-cutting rock is 0.87 %, with high estimation accuracy.

In this paper, the composite ZnS/MoS2 was obtained via two steps including solvothermal methods. The as-synthesized sample was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-Vis. diffuse reflectance spectra (DRS). The photocatalytic activity of the product was evaluated through photocatalytic degradation of Rhodamine B (Rh B) under UV-Vis. light irradiation; the electrical conductivity of ZnS/MoS2 composites was significantly improved compared to ZnS, MoS2, respectively. The results showed that the ZnS/MoS2 composite photocatalyst possesses better photocatalytic activity in degrading Rh B than the single ZnS or the single MoS2. The better photocatalytic properties may be due to the synergetic effect of two semiconductors, because of which electrons and holes were separated effectively. And its specific microstructure played an active role in evaluating photocatalytic performance.

Permanent magnetic-electromagnetic hybrid suspension system can effectively reduce energy consumption and heat release of the system, but also increase the difficulty of suspension control because of the existence of permanent magnets. The traditional current feedback control method is not conducive to the stability of the system and is difficult to debug. In this paper, the models of permanent magnetic-electromagnetic hybrid suspension system based on current feedback and magnetic flux density feedback are established. The effects of current feedback and magnetic flux density feedback on the stability of the system are analyzed in theory and the advantages of flux density feedback are pointed out. The model of magnet flux feedback is simple and it can overcome the disadvantages of current feedback, which is beneficial to the stability of the system. The magnetic flux density feedback control of permanent magnetic-electromagnetic hybrid suspension system is realized by simulation and experiment. Control system performs well and is easy to debug.

Equipment Failure Root Cause Analysis (ERCA) methodology is employed in this paper to investigate the root cause for charging pump’s pressure fluctuation of chemical and volume control system (RCV) in pressurized water reactor (PWR) nuclear power plant. RCA project task group has been set up at the beginning of the analysis process. The possible failure modes are listed according to the characteristics of charging pump’s actual pressure fluctuation and maintenance experience during the analysis process. And the failure modes are analysed in proper sequence by the evidence-collecting. It suggests that the gradually untightened and loosed shaft nut in service should be the root cause. And corresponding corrective actions are put forward in details.

A three dimensional model for material deposition in Selective Laser Melting (SLM) with application to Al2O3-ZrO2 eutectic ceramic is presented. As the material is transparent to laser, dopants are added to increase the heat absorption efficiency. Based on Beer-Lambert law, a volumetric heat source model taking into account the material absorption is derived. The Level Set method with multiphase homogenization is used to track the shape of deposed bead and the thermodynamic is coupled to calculate the melting-solidification path. The shrinkage during consolidation from powder to compact medium is modeled by a compressible Newtonian constitutive law. A semi-implicit formulation of surface tension is used, which permits a stable resolution to capture the gas-liquid interface. The formation of droplets is obtained and slight waves of melt pool are observed. The influence of different process parameters on temperature distribution, melt pool profiles and bead shapes is discussed.