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Piezoelectric accurate actuation plays an important role in industrial applications. The intrinsic frequency of previous actuators is invariable. However, variable frequency can approach the range near the low-intrinsic-frequency and realize a high actuation capability. The frequency-variable linear and rotary motion (FVLRM) principle is proposed for rotor-blade-based two-degree-of-freedom driving. Inertial force is generated by frequency-variable piezoelectric oscillators (FVPO), the base frequency and vibration modes of which are adjustable by the changeable mass and position of the mass block. The variable-frequency principle of FVPO and the FVLRM are recognized and verified by the simulations and experiments, respectively. The experiments show that the FVLRM prototype moves the fastest when the mass block is placed at the farthest position and the prototype is at the second-order intrinsic frequencies of 42 Hz and 43 Hz, achieving a linear motion of 3.52 mm/s and a rotary motion of 286.9 mrad/s. The actuator adopts a lower operating frequency of less than 60 Hz and has the function of adjusting the natural frequency. It can achieve linear and rotational motion with a larger working stroke with 140 mm linear movement and 360° rotation.

Conventional motors with complicated electromagnetic structures are difficult to miniaturise for millimetre- and centimetre-sized robots. Instead, small-scale robots are actuated using a variety of functional materials. We proposed a novel robot propelled by a piezoelectric ceramic in this work. The robot advances due to the asymmetric friction created by the spikes on the surface. The structural modelling was completed, static and dynamic models were established to predict the moving characteristics, the prototype was built using three dimensional (3D) printing technology, and the models were evaluated via experiments. Compared with conventional inchworm-type robots, the proposed robot is superior in simple structure because the clamping components are replaced by spikes with asymmetric friction. Compared with SMA (shape memory alloy) actuating inchworm-type robots, it has a faster velocity with higher resolution. Meanwhile, the components are printed through an additive manufacturing process that is convenient and avoids assembly errors. This design could make contributions to many areas, such as pipe inspection, earthquake rescue, and medicine delivery.

A compact, orthogonally polarized, gain-switched a-cut Ho:LuLiF4 laser with intra-cavity pumping by a self-Q-switched Tm:YAP laser is demonstrated here for the first time. The π-polarization laser at 2052 nm and σ-polarization laser at 2066 nm were experimentally observed with the maximum output power values of 299 mW and 126 mW, respectively, and the two polarization directions were always kept mutually orthogonal as the pump power increased. The ratio of the output power between the two orthogonal polarization lasers was nearly 1:1 at a pump power of 18.4 W. The minimum pulse width of the Ho:LLF laser was 326 ns, the maximum repetition rate was 24 kHz, and the maximum average energy was 28 μJ.

Purpose This paper aims to compare the forecasting performance of different models with and without big data predictors from search engines and social media. Design/methodology/approach Using daily tourist arrival data to Mount Longhu, China in 2018 and 2019, the authors estimated ARMA, ARMAX, Markov-switching auto-regression (MSAR), lasso model, elastic net model and post-lasso and post-elastic net models to conduct one- to seven-days-ahead forecasting. Search engine data and social media data from WeChat, Douyin and Weibo were incorporated to improve forecasting accuracy. Findings Results show that search engine data can substantially reduce forecasting error, whereas social media data has very limited value. Compared to the ARMAX/MSAR model without big data predictors, the corresponding post-lasso model reduced forecasting error by 39.29% based on mean square percentage error, 33.95% based on root mean square percentage error, 46.96% based on root mean squared error and 45.67% based on mean absolute scaled error. Practical implications Results highlight the importance of incorporating big data predictors into daily demand forecasting for tourism attractions. Originality/value This study represents a pioneering attempt to apply the regularized regression (e.g. lasso model and elastic net) in tourism forecasting and to explore various daily big data indicators across platforms as predictors.

Pulmonary alveolar microlithiasis (PAM) is an autosomal recessive disorder with distinctive deposition of calcium phosphate microliths in the lungs. Mutation of the SLC34A2 gene was proved to be responsible for PAM. Here, we report the study of a family affected by PAM in China. Two daughters of an inbred family whose parents are cousins and are affected by PAM. Mutation analysis of the SLC34A2 gene by polymerase chain reaction (PCR) amplification and direct sequencing in both patients revealed that exon 5 was deleted on both alleles. Both parents of the patients are proved to be carriers of the mutated allele. Gap-PCR was performed to determine the breakpoints and a homologous deletion of 1152 bp encompassing exon 5 of the SLC34A2 gene (c.IVS4+1452_IVS5+660del) was confirmed. A 4-bp fragment of TGGG was located on the edge of both upstream and downstream breakpoints. The upstream breakpoint lies in the same region as the breakpoint of a fused gene SLC34A2–ROS1, which encodes a constitutive kinase in the lung cancer cell line HCC78 and nonsmall-cell lung cancer (NSCLC), suggesting that the deletion in this family is a hot spot for recombination, not only in cancer samples with somatic mutation, but also in PAM patients with germline genetic defects of SLC34A2.

In the realm of welding production, optimizing parameters for enhanced quality and efficiency remains a challenge. This study introduces a novel approach using ABAQUS for simulating the thermal–mechanical behavior in T-shaped double-sided welded joints of Q345 steel. Initial simulations were experimentally validated. A range of welding parameters was then established, and the “Unifrnd” function helped sample within this range. This study considers eight welding parameters as input variables for an artificial neural network (ANN), trained to predict residual stress and deformation. Optimization algorithms NSGA-II (non-dominated sorting genetic algorithm-II) and MOPSO (multi-objective particle swarm optimization) algorithm were employed to refine the ANN's outputs. Notably, the Pareto front revealed an optimal balance between minimizing residual stress and deformation. While single optimization achieved up to 5.12% reduction in residual stress and over 50% in deformations, the tri-objective optimization resulted in a more balanced reduction (about 1.88% in residual stress and over 20% in deformations). This highlights the need for parameters weighting in decision-making. The findings demonstrate the effectiveness of integrating ANN with optimization algorithms for welding parameter optimization, with implications for improved welding practices. Graphical abstract

Researchers are paying increasing attention to questions of community leadership and rural tourism development. Based on leadership theories and the literature on community leadership and tourism development, this study developed a framework for community leadership in rural tourism development and used it to examine two ancient Chinese villages. We used the longitudinal case study method to collect data, and we used textual analysis to analyze these data. The results show that the rebel leadership characteristic of confrontational actions played an important role in starting the tourism industry in both villages. However, this leadership was difficult to maintain because community leaders and residents had limited power compared to that of outsiders. Losing control of tourism development in the two villages led to banal management, which prevented the emergence of strong community leadership. In the future, we argue that resilient community leadership should be nurtured in the two villages to address more complex problems occurring in tourism development, such as those characterized by vision tensions and conflicts of interest among the stakeholders affected by tourism development. Finally, we suggest that, based on the longitudinal method, future research can focus on the relationship between resilient leadership and the resilience of tourism communities.

Acute lung injury (ALI) is mainly characterized by diffusive injuries to lung epithelium and increased permeability of alveolar-capillary membranes caused by various factors, which leads to pulmonary edema and pulmonary closure. Lipopolysaccharide (LPS), which is the main component of the cell wall of gram-negative bacteria, is one of the most important factors causing pulmonary infection and ALI. More and more reports have indicated that hydrogen sulfide (H 2 S) is closely correlated with ALI and has anti-inflammation function, while the specific mechanism needs further investigation. Cholecystokinin-octapeptide (CCK-8), which is an important endogenous functional fragment belonging to CCK family, participates in anti-inflammatory and anti-endotoxic shock (ES). Whether CCK-8 plays important roles in curing ALI also needs further investigation. Herein, we concluded that CCK-8 alleviated the ALI induced by LPS via regulating the catalytic activity of cystathionine γ-lyase (CSE) and the formation of H 2 S. This work provides new medicine-designed target for clinical doctor to prevent and cure ALI.

Acute lung injury (ALI) is mainly characterized by diffusive injuries to lung epithelium and increased permeability of alveolar-capillary membranes caused by various factors, which leads to pulmonary edema and pulmonary closure. Lipopolysaccharide (LPS), which is the main component of the cell wall of gram-negative bacteria, is one of the most important factors causing pulmonary infection and ALI. More and more reports have indicated that hydrogen sulfide (H2S) is closely correlated with ALI and has anti-inflammation function, while the specific mechanism needs further investigation. Cholecystokinin-octapeptide (CCK-8), which is an important endogenous functional fragment belonging to CCK family, participates in anti-inflammatory and anti-endotoxic shock (ES). Whether CCK-8 plays important roles in curing ALI also needs further investigation. Herein, we concluded that CCK-8 alleviated the ALI induced by LPS via regulating the catalytic activity of cystathionine γ-lyase (CSE) and the formation of H2S. This work provides new medicine-designed target for clinical doctor to prevent and cure ALI.

The bridge-type displacement amplifier is modeled by the analytical method and finite element method. The analytical relationship between the input displacement and output displacement is established. The analytical model is validated by finite element method. The geometric parameters influence of amplification ratio is studied. The comparison results show that the link length and the link angle influence the amplification ratio dramatically. A small link angle and a large link length is beneficial to the amplification ratio. The finite element method has a more precise simulation results than the analytical method under the circumstance of small link angle and short link length.