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• A leakage flow estimation model based on swashplate position and operating conditions is established by a displacement transducer at actuator piston. • An indirect flow measurement for a bi-tandem axial piston pump is proposed by considering leakage, flow ripple, and compressibility. • The method enables output flow monitoring and feedback without the need for flowmeters in pump-controlled hydraulic systems, avoiding additional energy consumption and cost increase. In pump-controlled hydraulic systems, configuring a flowmeter at a variable piston pump to monitor output flow causes additional losses. A method for indirect flow measurement of the bi-tandem axial piston pump based on flow leakage estimation is proposed to address this problem. The method first installs a displacement transducer at the actuator piston to collect data on the actuator piston position, outlet pressure, and shaft speed, then estimates leakage of key kinematic pairs, and finally considers flow ripple and fluid compressibility to form an indirect measurement for output flow of the pump. The indirect measurement accuracy under various typical operating conditions is analyzed. The results demonstrate that the mean absolute percentage error of the proposed indirect flow measurement method is less than 2.10%, and the method is effective with high measurement accuracy. The indirect measurement method avoids extra costs and energy consumption associated with configuring flowmeters in engineering hydraulic systems. [ABSTRACT FROM AUTHOR]

• The force on the surface unit of the crankpin exhibits consistency within the cycle. • There is a law of force variation at each crank pin of the crankshaft. • There is a correlation between crankshaft force and load condition with flow rate. The stability and safety of emulsion pumps are significantly influenced by crankshafts. However, the crankshaft of the emulsion pump bears complex torsional and bending stresses during operation; thus, it is prone to failure. The purpose of this paper is to determine the dynamic response of the crankshaft under various working conditions. The mechanical model of the power end of the emulsion pump is constructed, and the dynamic model is established by LS-DYNA. The stress distribution characteristics of the surface element of the crankpin in the pulsating impact cycle are analysed, and the dynamic response of the crankpin under multiple working conditions is studied. The results show that under the action of pulsating impact, the edge position of the crankpin is more likely to fail, especially at the second crankpin, and the maximum stress can reach 213 MPa. The dynamic impact of the connecting rod on the crankpin is positively correlated with the flow of the emulsion pump and the hydraulic pressure on the plunger, and the crankshaft vibration becomes more noticeable as the flow rate rises. Doubling the flow rate increases the vibration by 73.9 %. Our research results provide a reference for avoiding the failure of the crankshaft and optimizing the design. [ABSTRACT FROM AUTHOR]

Highlights • Based on the Flores contact model, we establish the dynamic model of spherical rocks vertical impact on the metal plate with the considering the energy absorbed and consumed by the compression of the rock and energy absorbed by the bending deformation of the metal plate. • Based on the Drucker–Prager criterion, we obtain the function of maximum comprehensive stress ε 0 (α, μ 1) and deduced the initial yield stress and initial yield impact velocity for the consideration of principal stress σ2. • We propose the approximate theoretical formula of the maximum contact compression of spherical rocks based on recursive solution. Influence law of impact velocity, material parameters and structure size on the dynamic response of the impact system is obtained. • The combining simulation based on ADAMS and Hypermesh was used to verify the correctness of the theoretical model. Abstract In the process of top coal caving mining, the metal sheet of the tail beam of the hydraulic support will vibrate when coal and rock particles start to impact the tail beam. In the impact between the particles and the metal plate of finite dimension, there are many complicated problems such as short duration of impact, rapid enhancement of transient stress, local large deformation of particles and macroscopic deflection of the metal plate are involved. However, the analysis of the contact force between the spherical particles and other objects is still simplified to the ideal Hertz contact problem. In order to study the real contact states of coal and rock particles impact on the metal plate, we simplified the working conditions from the coal and rock particles impact the tail beam in top coal caving mining to the system that spherical particles have similar properties to coal or rocks impact vertically on the metal plate. Based on the Flores contact theory and the energy absorbed by the bending deformation of the metal plate, the contact model of spherical rock at the compression stage was established. At the same time, we researched the initial yield stress and initial yield impact velocity of spherical rock that obeys the Drucker–Prager (D–P) criterion and proposed the approximate theoretical calculation method of maximum contact compression of spherical rocks. In the range of elastic impact velocity, the influence of impact velocity, restitution coefficient, material parameters and structure sizes on the dynamic response of the system were also analyzed. Finally, the correctness of the theoretical model has been verified by the virtual prototype simulation combined by ADAMS and Hypermesh. The research will provide the basic theory reference for the recognition technology of a single particle of coal or rock that based on the impact vibration of the tail beam. [ABSTRACT FROM AUTHOR]

In order to study the support failure mechanism of a super-large mining height powered support, a mathematical model of the load carrying capability area (LCCA) under various loading conditions for the support was established. A certain type of support was considered as an example, and the distribution characteristics of the LCCA were analyzed. According to the results of theoretical analysis, a dynamics numerical simulation model based on the ADAMS software was developed. The response of the support was observed under conditions of various loading intensities and positions. The simulation results demonstrated that deviation of the roof load from the optimal equilibrium area (OEA) was the key reason for the support failure. Subsequently, the factors affecting the OEA of the support were analyzed and the analysis result appraisal was executed by the load carrying capability theory. The results demonstrated that optimization of the structural parameters of the powered support was reasonably conducive to the range expansion of the OEA. Therefore, the support failure tendency could be reduced. The research results were useful in the structure optimization of the powered support, thus improving the corresponding reliability and stability. [ABSTRACT FROM AUTHOR]

• A topology optimization design of the stiffness-tunable structure is proposed. • The proposed deep learning metastructure design method is faster than optimization. • Multi-scale design based on neural network is realized. • Bionic structure design with gradient characteristics, applied to the structural design of hip joint. Mechanical metamaterials with unique micro-architectures possess excellent physical properties in terms of stiffness, toughness, vibration isolation, and thermal expansion. Meanwhile, meta-structures in organisms or geography operate efficiently under complex service conditions thanks to their heterogeneous and gradient distribution of naturally evolved micro-architectures that are difficult to obtain by forward design. In this paper a multi-network deep learning system that satisfies the different design property requirements of microstructures is proposed, and the network predicts the configuration with 99.09% accuracy. The analogy between color space and mechanical parameter space is used to transform parametric design into pixel matching. The microstructures are prepared by AM (additive manufacturing) and their properties are verified by DIC (Digital Image Correlation) experiments (the property error of the structures was less than 2%). Multiscale inverse design of multifunctional and gradient mechanical metamaterials is realized, with special attention payed to the automatic customization of biomimetic structures. The design flow takes only 2 s and the geometric connectivity between microstructure units is considered to ensure compatibility between adjacent microstructures for AM. The proposed design strategy accelerates the emergence of high-performance structures, and provides a reference for topology optimization design of mechanical metamaterials. [Display omitted] [ABSTRACT FROM AUTHOR]

Three dopant-free hole-transporting materials (HTMs) M1−3 containing dithieno[3′,2':3,4;2″,3'':5,6]benzo[1,2-d]imidazole (DTBI) or phenanthro[9,10-d]imidazole (PTI) were designed, synthesized and applied in perovskite solar cells (PSCs), where DTBI and PTI were first introduced as a core structure in the HTMs. Different steric groups (4-methoxybenzene and 4,4′-dimethoxytriphenylamine) were introduced as the periphery groups connected at carbon-2 (C-2) position of imidazole moiety. Accordingly, the relationship between chemical structure and function was systematically investigated with respect to the fused cores and periphery groups, by the measurements of the energy levels, hole mobility, film-forming morphology, extraction and transfer of photo-generated holes, and photovoltaic performances. It was found that M1−2 with DTBI as a core structure exhibited suitable energy levels, higher hole mobility and uniform film-forming morphology, as well as efficient extraction and transfer of photo-generated holes at the perovskite/HTM interfaces. The PSCs using M2 as dopant-free HTM exhibited an impressive power conversion efficiency (PCE) of 16.9% with a negligible hysteresis, surpassing that of the doped spiro-OMeTAD-based standard device (16.4%) under the same testing conditions. Importantly, the unencapsulated PSCs based on dopant-free M2 presented much higher stability than that of doped spiro-OMeTAD. This work provides a promising strategy to construct dopant-free HTMs with both high efficiency and high stability by using DTBI as a core structure. Image 1 • HTM with dithieno[3′,2':3,4;2″,3'':5,6]benzo[1,2-d]imidazole as core is designed. • They are applied in PSCs as dopant-free hole-transporting materials (HTMs). • They exhibit suitable energy levels and high hole mobility. • They exhibit much higher stability over the doped spiro-OMeTAD in the ambient air. [ABSTRACT FROM AUTHOR]

The investigation on the effect of defects on the mechanical properties of composites is vital to explain the failure mechanism of materials. A computer tomography (CT) scanning in-situ shear test is designed to obtain u-CT images of plain weave glass-fiber reinforced composites. The images are then applied to reconstruct the samples by using image processing techniques. Damage evolution characterization of the plain weave glass-fiber composites under in-situ shear experiment are realized by visualizing damages in three dimension. The damage evolution process is compared with the numerical simulation results to verify the materials failure mode. [ABSTRACT FROM AUTHOR]

• Three SFX-based dopant-free HTMs with different donor units were synthesized. • The effects of the donor units of HTMs on photophysical properties were systematically investigated. • The SFX-2CZ based PSCs exhibited a high efficiency of 15.83% without dopants. Three spiro[fluorene-9,9′-xanthene] (SFX)-based organic molecules with different donor units were synthesized and used as dopant-free hole-transport materials (HTMs) in perovskite solar cells (PSCs). The end-capping donor units on the SFX core are two methoxydiphenylamine-substituted diphenylamine (MDDPA), two and four methoxydiphenylamine-substituted carbazole (MDCZ) for SFX-2DPA , SFX-2CZ and SFX-4CZ , respectively. The structure-function relationship is systematically investigated as the impact of the different donor units upon the optical, electrochemical and photophysical properties of SFX-based HTMs. The PSCs based on SFX-2CZ attain the higher power conversion efficiency (PCE) of 15.83% than that based on SFX-2DPA (14.25%), due to higher molecular planarity of SFX-2CZ with enhanced hole transporting ability and the downshifted HOMO level. On other hands, SFX-4CZ has the lowest efficiency (12.19%) among three HTMs mainly due to its inferior film-forming ability. The results provide not only the new molecular design of dopant-free organic HTMs based on SFX core, but also a promising strategy to develop efficient HTMs with both the molecular planarity and number of donor groups being considered. [ABSTRACT FROM AUTHOR]

Cu/SSZ-13 catalysts not only exhibit superior SCR performance but also possess excellent selective catalytic oxidation (SCO) ability to remove NH 3 escaped from engine exhaust gas fueled by NH 3. To elucidate the effect of Cu loading on Cu/SSZ-13 catalysts, a series of Cu/SSZ-13 catalysts were prepared through wet impregnation method to remove high-concentration NH 3 (5000 ppm). The SCO activity test results showed that when Cu loading increased from 1% to 10%, there was an obvious improvement effect on NH 3 conversion performance at low temperature. Cu 10 /SSZ-13 catalyst reached a high NH 3 conversion of 96% at 250 °C, and N 2 selectivity was higher than 86% in the whole temperature range. However, when further increasing Cu loading from 10% to 20%, there was no distinctive difference in NH 3 conversion and N 2 selectivity. The characterization results indicated that there were abundant active species, adsorbed oxygen species, and acid sites on the surface of Cu 10 /SSZ-13 catalyst. The [Cu(OH)]+ and isolated Cu2+ species in zeolite channels of Cu 10 /SSZ-13 catalyst rather than CuO species on the surface played a key role in NH 3 -SCO reactions. Since 20% Cu loading would result in a significant decrease in isolated Cu2+ species, it resulted in both [Cu(OH)]+ species in zeolite channels and superfluous Cu species on zeolite surface being main active species in NH 3 -SCO reactions. In-situ DRIFTS experiments suggested that NH 3 -SCO reactions over Cu/SSZ-13 catalysts followed the internal selective catalytic reduction (i-SCR) mechanism. [Display omitted] [ABSTRACT FROM AUTHOR]

• An indirect measurement model for coal and rock interface identification is proposed by quantitative analysis of rock proportions in cutting range. • The model is still applicable even if in conditions where rock material properties are unknown in advance. • The method is also applicable for interface identification of two kinds of material in other rotary cutting machine in addition to shearer drum in the paper. In coal mining industry, direct measurement on rock proportions is difficult due to various rock material properties. Aiming at identification of coal and rock interface, the paper proposed a method by indirect measurement on rock proportions with contact force and some measures to improve the measurement accuracy as well. To establish the measurement model, cutting forces under different kinds of working states are studied with theoretical analysis and the relations between rock proportions and dynamic force are established. For validation, general circumstances with various rock properties and motion parameters in mining process are studied and estimation results of rock proportions in those circumstances are analyzed. Results show that the measurement accuracy is stable even if parameters related with rock properties and drum working parameters are different. Therefore, the mentioned parameters are no longer essential in advance for indirect measurement of rock proportion. In addition, stochastic fragmentation of coal or rock always leads to fluctuation on measurement accuracy. With the improved cluster method, the mean accuracy of this model are close to 90% and sometimes, the measurement accuracy is even more than 95%. The method in this paper is meaningful for identification of coal and rock interface and in this way could guide the shearer drum to avoid hard rock to reduce the damage on mining equipment. [ABSTRACT FROM AUTHOR]

• The construction process from eigenvector to eigenmatrix is realized. • A multi-layer time domain feature extraction method is proposed. • A method of eigenmatrices series based on multi-layer processing data is proposed. • A method of feature fusion based on cross-optimal selection (FFCOS) was proposed. Accurate and rapid recognition of coal gangue is an important link to realize automatic mining, which is helpful to improve the efficiency of coal mining and the safety of mining workers. Relevant studies have confirmed the effectiveness of coal gangue recognition based on tail beam vibration signal, but the recognition accuracy of a single point source vibration signal of tail beam is slightly low. In order to improve the practicability of coal gangue recognition method based on tail beam vibration signal, this paper takes the single source tail beam vibration signal as the object, improves the coverage of tail beam vibration characteristics by conducting experiments and extracting multiple vibration signals at different positions, and conducts the research on coal gangue recognition technology by multi-layer time domain feature processing and cross-optimal fusion of multiple signals. Firstly, through analysis of classification algorithm ability and coal gangue recognition principle, the coal gangue recognition process is formulated and the classification model is constructed. Then, based on the two data samples of a single signal eigenvector and multi-signal eigenmatrix obtained by Direct Data Statistics (DDS), the recognition research is carried out, and the recognition effectiveness of the eigenmatrix is verified. Based on this conclusion, the three-layers eigenmatrix data samples of DDS, EMD Data Statistics (EDS) and HHT Data Statistics (HDS) are obtained by multi-layer time domain feature processing, and the coal gangue recognition based on multi-layer eigenmatrix is carried out respectively. DDS is the most accurate signal processing method. On this basis, the construction method of DDS + EDS and DDS + HDS recognition eigenmatrix based on array series is studied, and the recognition ability of DDS + HDS recognition eigenmatrix construction method and Logic Regression algorithm is proved. Recognition accuracy based on DDS + HDS recognition eigenmatrix and Logic Regression algorithm is up to 95.25 %. Finally, in order to further improve the recognition accuracy and response speed, this paper proposes a method of feature fusion based on cross-optimal selection (FFCOS). Features of DDS and HDS are sorted by recognition sensitivity, and then cross-selected and fused according to this sort. The results show that the recognition accuracy of the serial construction method of DDS + HDS recognition eigenmatriX array and the Logistic Regression algorithm can reach 97 %, which proves the effectiveness of the FFCOS method and realizes the accurate recognition of coal gangue based on the vibration signal of single source tail beam. [ABSTRACT FROM AUTHOR]

Developing deep-sea drilling mechanisms based on new driving modes is important for promoting marine geological surveys and marine mineral resource exploration. We propose an underwater ultrasonic drill (UUD) for seabed rock drilling based on the piezoelectric driving principle and underwater rock-breaking mechanism. The driving device of the UUD was designed using piezoelectric vibration theory, and its performance parameters were predicted through simulations. A prototype of an ultrasonic drill suitable for underwater drilling was designed considering the working environment and drilling objects. To verify the drilling performance of the UUD, a drilling efficiency test system was set up, the influence law of key structural and dynamic parameters on drilling efficiency was studied using the orthogonal experiment method, and the optimal parameter combination was explored. The maximum drilling efficiency of UUD reached 32.29 mm/min in sandstone with a compressive strength of 20 MPa when the excitation frequency and voltage were 16,150 Hz and 780 V P-P , respectively. The feasibility of UUD for rock drilling in the seabed was verified through comparison and power-testing experiments. Research on the UUD prototypes can provide new ideas for exploring deep-sea resources. • An underwater ultrasonic drill is proposed and its test prototype is fabricated. • The piezoelectric actuator is designed and its performance is verified by experiments. • The influences of key structural parameters and dynamic parameters on drilling performance are investigated. • The feasibility of the UUD for rock drilling in the seabed is verified by experiments. [ABSTRACT FROM AUTHOR]

Pentraxin 3 (PTX3) is a soluble pattern recognition molecule in the innate immune system that has multiple functions. It is involved in resisting pathogen infection. However, the functions of PTX3 in teleost fish are not well understood. In this study, we identified and characterized PTX3 in Nile tilapia (Oreochromis niloticus) (OnPTX3). The open reading frame of OnPTX3 was found to be 1305 bp, encoding 434 aa. We conducted spatial mRNA expression analysis and found that the expression of OnPTX3 was significantly increased after infection with Streptococcus agalactiae and Aeromonas hydrophila , both in vivo and in vitro. We also observed that recombinant OnPTX3 protein could bind and agglutinate bacterial pathogen. Furthermore, OnPTX3 enhanced the phagocytosis of bacteria (S. agalactiae and A. hydrophila) by head kidney macrophages. Additionally, OnPTX3 was found to influence the expression of inflammatory cytokines, suggesting its involvement in the regulation of the inflammatory response. Moreover, OnPTX3 was shown to promote complement-mediated hemolysis and possess antibacterial activity. In conclusion, our research demonstrates that OnPTX3 has bacterial binding and agglutination activities, enhances phagocytosis, and regulates inflammation. It plays a crucial role in the defense of Nile tilapia against pathogenic bacteria, providing valuable insights for the prevention and control of aquatic diseases in the future. • OnPTX3 exhibits the capability to bind and agglutinate bacterial pathogens. • OnPTX3 plays a role in the modulation of phagocytosis and the inflammatory response. • OnPTX3 is capable of engaging in complement-mediated cell lysis and possesses antibacterial activity. [ABSTRACT FROM AUTHOR]

The low central venous pressure (LCVP) technique is a key technique in hepatectomy, but its impact on acute kidney injury (AKI) is unclear. The purpose of this study was to explore risk factors (in particular LCVP time) for AKI following hepatectomy. A retrospective case–control study with propensity score matching. Operating room. A total of 1949 patients who underwent hepatectomy were studied. The patients were grouped with or without AKI within 7 days after surgery. Univariable and multivariable analyses were performed, including recognized intraoperative predictors. The final result is represented as a nomogram. Preoperative, intraoperative and postoperative data were collected. LCVP is monitored directly through a central venous catheter via the right internal jugular vein. AKI occurred in 148 patients (7.59%). Surgery time, minimum SBP, furosemide administration and norepinephrine were identified as independent risk factors. The area under the curve for the receiver operating characteristic curves was 0.726 (95% CI 0.668–0.783). Intraoperative parameters can be used to predict the probability of postoperative AKI. Although AKI increases the length of stay, it may not increase in-hospital mortality. LCVP time was not confirmed to be a risk factor for AKI. • A model for predicting 7-day AKI was developed in hospitalized hepatectomy patients. • The intraoperative urine volume was measured to detect AKI. • LCVP time was not confirmed to be a risk factor for AKI. • Our study also did not find that epidural anesthesia increased the incidence of AKI. [ABSTRACT FROM AUTHOR]

• A noncontact rotation actuator is proposed and its test prototype is fabricated. • The ultrasonic emitter and the rotor are designed and optimized. • The influences of the rotor structure and driving parameters on the contact-free rotation performance are investigated. The innovation of novel drive methods based on smart materials is an important way to promote the development of machines and equipment to the direction of high speed, high efficiency, clean and intelligence. Based on the piezoelectric drive principle and near-field acoustic levitation (NFAL) technology, a noncontact rotation actuator is proposed driven by ultrasonic energy. Under the action of ultrasonic energy generated by the ultrasonic emitter, the object can be stably levitated and driven to rotate at a certain speed. The electroacoustic conversion structure of the actuator is designed and its performance parameters are predicted. To verify the levitation and driving performance, a testing system for the actuator is developed. The structural and dynamic parameters' influence on the rotor motion are investigated by experimental means, and the optimal parameter combination is acquired. The experiment results show that the maximum driving speed of the optimized rotor can reach 3145 rpm and the maximum noncontact driving torque is about 1.24 mNm under the excitation frequency of 20.21 kHz and the excitation voltage of 225 V p-p. The proposed levitating drive method based on ultrasonic energy is expected to show great potential in the field of noncontact operation or actuation. [ABSTRACT FROM AUTHOR]

• Based on the idea of reverse modeling, a finite element modeling method for CT images is proposed. • NURBS is utilized to fit complex boundary of model, which can greatly improve the finite element computational efficiency while ensuring the accuracy of the model. • The mechanical properties and failure modes of interlocked structures were studied by experiments and simulations. • The failure mode of structure is related to arrangement of pores, which can be improved by adjusting the printing strategy. Suture-inspired interlocked interfaces in nature exhibit promising industrial application potentials for advanced mechanical structures, devices and equipment. It is of significant scientific interest for studying the pull-out response and failure mode of interlocked structure as well as internal stress variations during the loading process. In this paper, finite element analysis (FEA) simulation based on X-Ray tomographic images is proposed for understanding the effects of manufacturing defects on the performances of interlocked structures, which are of critical importance for controlling the stress evolution of the interface structure and corresponding failure modes. Firstly, X-ray micro computed tomography (micro-CT) was applied for non-destructive scanning inspection of aluminum alloy additive manufacturing samples, high spatial resolution and calculation efficiency can be realized through tomographic image guided FEA scheme for generating high fidelity simulation results. Afterwards, non-uniform rational B-splines fitting method was employed for optimizing sample boundaries harvested from CT images, which allows smooth conversion from CT pixel images to high precision fitted finite element model. The B-spine fitting model can significantly improve the computational efficiency for finite element simulation without losing calculation reliability and resolution, overcoming the inherent contradictions between efficiency and resolution of the traditional pixel image finite element method. Finally, considering the mechanical contributions and interactions of external and internal porosity defects, the failure modes of the interlocked structures were further analyzed based on the results of finite element analysis. [ABSTRACT FROM AUTHOR]

The unmanned sampling and analysis after return of seabed rocks is an important method for deep-sea mineral resources exploration. A novel underwater robot for ultrasonic drilling and sampling tasks of seabed rocks is proposed based on the bionic design method in this paper. The jellyfish-like structure is adopted for the swimming system of the robot, which can move flexibly and stably with low noise, outstanding cruising ability and strong environmental adaptability. The mechanical system and driving control strategy of the robot are designed in this paper. Based on co-simulation method of ADAMS and MATLAB software, the structural parameters of the transmission mechanism of the swimming system are optimized to get larger swing angle under relative less driving power, which will contribute to the improvement of propulsion efficiency. Through the fluid dynamics simulation and analysis in FLUENT software, the propulsion process can be visualized and the propulsion mechanism is revealed. To verify the feasibility of the design, a robot prototype is developed and the experimental platform for the robot's swimming test is built. The underwater experiments on motion characteristics for the robot demonstrates that the maximum propulsive force generated by the swimming system can reach about 16N, and the propulsion speed can reach 0.19m/s. The design and development of the bionic robot for seabed ultrasonic drilling and sampling missions provides new ideas for seabed resource exploration technology. [ABSTRACT FROM AUTHOR]

• The study focuses on non-contact manipulation base on ultrasonic energy. • Ultrasonic transmitting units' working parameters are accurately determined and validated. • Levitating, restoring and rotation-driving mechanisms are investigated theoretically and experimentally. • Relation between levitation force and excitation voltage is revealed for precise control. • Stable levitation and rotation of disc-shaped objects is achieved without physical contact. To avoid the problems of wear, scratching, and contact pollution caused by traditional physical contact operations on high-precision materials or parts, a non-contact manipulation concept based on the near-field acoustic levitation effect and piezoelectric drive theory is proposed. The contact-free handling device can stably suspend the disc-shaped object and drive the object to rotate at a certain speed under the action of ultrasonic energy. The stable levitation capacity of the contact-free handling device relies on the vertical suspending force and horizontal restoring force derived from the W-type acoustic wave generated by the acoustic emission units. If the upper surface of the suspended disk has a specific configuration, a component driving force is generated when acoustic radiation is applied to it. To explore effective methods to improve the levitation effect, acoustic emission units were designed and fabricated, mathematical models of the suspending force and restoring force were built based on nonlinear acoustics and aerodynamics theories, and the influencing factors of these forces were investigated. In addition, a testing system for a contact-free manipulating device was fabricated to verify the levitation and driving performance using experimental methods. [Display omitted] [ABSTRACT FROM AUTHOR]

The robust mechanical properties of architected micro lattice mechanical metamaterials are determined by their precisely designed artificial microstructures, and various types of mechanical metamaterials have been proposed for acoustic manipulation, impact energy absorption, vibration attenuation, etc. In this paper, 3D pyramid and hourglass micro lattice samples are fabricated with projection micro-stereolithography (PμSL) 3D printing technique. Synchrotron X-ray tomography 3D imaging at the sub-micrometer precision level is employed for characterizing surface roughness and internal void defects distribution induced by the manufacturing process. Afterwards, synchrotron X-ray tomography 3D imaging of the in-situ shearing deformation process is performed for studying the failure process and deformation modes of the as-fabricated micro-lattice samples. It is found that manufacturing surface roughness and internal defects within the lattice beams and nodes can significantly influence the deformation behaviors and failure modes of these shearing micro lattice samples. Finally, three types of finite elementanalysis (FEA) models based on synchrotron X-ray tomography 3D image reconstruction are proposed for understanding the relation between manufacturing defects and mechanical behaviors of micro lattices, where effects of statistical distributions of geometry defects of micro lattice structures are focused. Based on comparison between experimental and numerical results, it can be concluded that manufacturing defects can change the deformation behaviors and mechanical integrity of micro-lattice remarkably. [ABSTRACT FROM AUTHOR]