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In pursuit of design solutions that reduce energy loss and improve wear resistance for the piston–cylinder interface in an axial piston motor, a fluid-structure interaction numerical model and a new test rig of the friction force of the piston–cylinder pair are developed to achieve the analysis and design of the micro-geometric tapered-shape surface of a piston bore. The piston bore with the tapered-shape surface axial distribution length ratio of 49.44 % of the overall length is found to be the relatively optimized one. Furthermore, how the shaft speed, load pressure, and swash plate angle influence the performance of the two-type interface is analyzed. Numerical analysis results show that, compared with the traditional cylindrical piston bore design, the piston–cylinder interface with the optimized tapered-shape piston bore in the axial piston motor can achieve a significant reduction in leakage flow and friction force, and the experimental results are consistent with the simulation results.

The gas–solid fluidized bed is the key structure of industrial fluidization, and it is widely used in fields such as chemical reactors and industrial material conveying. To study the uniformity of velocity distribution ( Vu) in a fluidized bed and clarify the interaction mechanism between the geometric structure of the air chamber and the gas flow, in this paper, 16 novel chamber structures for powder unloading were designed based on the Taguchi method. Computational fluid dynamics was used to simulate the different chamber schemes, and the effects of various geometric factors on the response were analyzed based on the Taguchi method. The effect of the novel optimization model for powder unloading was verified by tests. The results show that the optimal combination of geometrical parameters is air chamber capacity ( V) at level 4, separation ratio ( K) at level 1 and clearance of splitter plate ( δ) at level 1, and δ has the greatest effect on the Vu1 and Vu2 in the fluidized bed. With the increase in δ and K, the velocity of the airflow away from the inlet side increases, and the area of the vortex near the splitter plate increases. Compared with the baseline model, the fluidized bed with the novel air chamber can effectively reduce the residual rate of powder unloading.

The fluidized bed is a key structure in the field of material transportation and is widely used in special automobile and construction powder transportation. A novel flat-cloth airway structure for powder unloading was proposed based on the traditional fluidized bed in this study. To analyze the uniformity of the velocity distribution ( Vu) in the fluidized bed and clarify the interaction mechanism between the geometric structure of the fluidized bed and airflow, 16 geometric structures of the fluidized bed for powder unloading were designed. Different schemes of the fluidized bed were numerically calculated by computational fluid dynamics, and the advantages of each scheme were analyzed by the Taguchi method and multiple regression. The length of the annular vortexes at the inlet of the airways becomes shorter than before as the number of airways increases. Airway height ( H), airway angle ( θ) and airway arc length ( L) exert statistically significant effects. Specifically, H (Delta = 6.45 rank =1) has the greatest effect on signal-to-noise ratios, L (Delta = 2.60 rank =2) has the second greatest effect and θ (Delta = 1.82 rank =3) has the least effect. The optimal combination of geometrical parameters of the fluidized bed is 15 mm H, 51° θ and 200 mm L.

This paper utilizes displacement amplifying mechanism and resonance drive to improve the output performance of piezoelectric pump. A rhombic piezoelectric actuator is designed and simulated with a piezoelectric stack (10 mm×10 mm×18.2 mm) and a rhombic displacement amplifying mechanism. Modal analyses of the rhombic piezoelectric actuator are carried out under fixed-vibrating constraint and symmetric constraint. The simulation results show that the resonant frequencies of the actuator in bending vibrating mode under fixed-vibrating and symmetric constraints are 724.6 Hz and 3205.9 Hz respectively. Then piezoelectric pumps are designed with two types of rhombic piezoelectric actuators vibrating two diaphragm pumps simultaneously in a symmetric structure. High flowrates output of the presented piezoelectric pumps design can be expected.

The hydrofoil, a basic blade cross-section shape, is widely used in various hydraulic machinery. We establish two bionic hydrofoil models (Sside and Stop) through 3D reverse engineering and numerically simulate these models with large eddy simulation to reveal the transient evolution mechanism of the cavitating flow of a bionic hydrofoil. The simulation results of the classic Clark-Y hydrofoil are highly consistent with the experimental results. In a single cycle, the lift–drag coefficient is related to the leading edge amount and cavity range. The cavitation number affects the lift–drag coefficient and cavity length L, and large cavitation numbers are associated with small values of lift–drag coefficient and cavity length. In contrast to the Sside scheme, the Stop scheme forms a relatively stable attachment vortex near the leading edge, the influence range of the vortex stretching is weak, and the baroclinic torque term that determines the cavity vortex is enhanced. The pressure fluctuation shown by the trailing edge of the bionic hydrofoil is significantly greater than that shown by the leading edge, and the main frequency of pressure fluctuation is proportional to the cavitation number.

As a typical Palaeozoic island arc system, the eastern Tianshan area, Xinjiang, is different from eastern China but similar to the Meso-Cenozoic island arc metallogenic provinces along the coast of the Pacific Ocean in metallogenic environment, geology and geochemistry. Three types of gold deposits, ductile shear zone-hosted gold deposits (Kanggur ), magmatic hydrothermal gold deposits (Jinwozi) and volcanic- or subvolcanic-hosted gold deposits (Xitan and Mazhuangshan), have been identified in this area. Regionally, gold deposits are structurally controlled by the Kanggur Tag ductile shear zone, Shaquanzi fault, Hongliuhe fault and Yamansu fault. Generally, gold mineralization occurs in the transition zones from volcanic rocks to sedimentary rocks. The horizon bearing well-developed jasper is an important indicator for gold mineralization. Each of the three types of gold deposits has its distinctive metallogenic background and geological-geochemical characteristics.

The superlarge Baguamiao, large Liba and Xiaogouli gold deposits represent three typical gold deposits different from the Carlin type in the western Qinling Orogenic Belt. Based on Ar-Ar dating of quartz from ores, U-Pb dating of single zircon from granite, tracing of H and O isotopes and studies on the mineralogy and texture of spots and bleached alteration developed in wall rocks, this paper focuses the relations between gold deposits and granite to clarify the origin of gold deposits and the metallogenesis in the tectonic evolution of the Qinling Orogenic Belt. The comprehensive studies show that the age of the granite (148.1-244 Ma) is identical with that of the gold deposits (131.91-232.56 Ma). It is suggested that the granite has close temporal, spatial and genetic relationship with the gold deposits. The granite provides a heat source, water source and considerable amount of ore-forming material. Finally, it is concluded that the orogeny by collision, emplacement of the granite and positioning of the gold deposits represent a successive process. Both the granite and gold deposits resulted from the syn-orogeny and post-orogeny tectonic evolution.

On the basis of the mechanism of formation of mineral inclusions, it may be assumed that a certain relation exists between the compositions of fluid inclusions in various minerals formed at the same stage of hydrothermal activity. In order to study the genetic relationships between different minerals in the Bayan Obo iron deposit, the compositions (K+, Na +, Ca+, Mg+, F+, Cl+, CO2−2, ∑SO2−4 and pH) of inclusions in fluorite (23), hematite (13), magnetite (3), sodium pyroxene (2) and dolomite (5) from the main mine and the eastern mine were determined by using the vacuum decrepitation and leaching methods, and cluster analyses of the data on the compostions were made. The Q-mode cluster analysis indicates that some iron oxide minerals in the deposit are related to dolomite of sedimentary origin, while others are related to fluorite and sodium pyroxene — products of hydrothermal activity. The R-mode cluster analysis shows that the components of the leaching solution may be divided into two groups: one includes CO2−2, Mg2+ and H+ (pH), which are obviously associated with dolomite; the other comprises Na+, K+, Ca+, F+, Cl+ and SO2−4, which may possibly represent the composition of hydrothermal solutions. The reaction of the Na-F-Cl solution (pH 4.72) with hematite dolomite at 300°C and 5 × 107 Pa and under alternately “static and dynamic” conditions produced large amounts of hematite and fluorite and small amounts of smectite and Na (Fe) silicates, and the hematite-fluorite assemblage accords with the actual geological conditions in the deposit. From a comparison between the compositions of “static” and “dynamic” solution samples, it may be known that the flow reaction facilitates the migration of Fe, F, Ca and other components as well as Na-metasomatism (Na and Si are fixed in a solid phase). The study of the compositions of mineral inclusions and simulation experiments on hydrothermal metasomatism have provided new evidence for the hypothesis of metamorphosed-sedimentary and hydrothermal-remoulding origin of the Bayan Obo deposit, and pointed out emphatically that hydrothermal metasomatism plays an important role in the formation of the mineral deposit, particularly in the main and the east mine.