Variational Mode Decomposition-Informed Empirical Wavelet Transform for Electric Vibrator Noise Analysis

Electric vibrators find wide applications in reliability testing, waveform generation, and vibration simulation, making their noise characteristics a topic of significant interest. While Variational Mode Decomposition (VMD) and Empirical Wavelet Transform (EWT) offer valuable support for studying signal components, they also present certain limitations. This article integrates the strengths of both methods and proposes an enhanced approach that integrates VMD into the frequency band division principle of EWT. Initially, the method decomposes the signal using VMD, determining the mode count based on residuals, and subsequently employs EWT decomposition based on this information. This addresses mode aliasing issues in the original method while capitalizing on VMD’s adaptability. Feasibility was confirmed through simulation signals and ultimately applied to noise signals from vibrators. Experimental results demonstrate that the improved method not only resolves EWT frequency band division challenges but also effectively decomposes signal components compared to the VMD method.

Selective liquid directional steering enabled by dual-scale reentrant ratchets

Achieving well-controlled directional steering of liquids is of great significance for both fundamental study and practical applications, such as microfluidics, biomedicine, and heat management. Recent advances allow liquids with different surface tensions to select their spreading directions on a same surface composed of macro ratchets with dual reentrant curvatures. Nevertheless, such intriguing directional steering function relies on 3D printed sophisticated structures and additional polishing process to eliminate the inevitable microgrooves-like surface deficiency generated from printing process, which increases the manufacturing complexity and severally hinders practical applications. Herein, we developed a simplified dual-scale structure that enables directional liquid steering via a straightforward 3D printing process without the need of any physical and chemical post-treatment. The dual-scale structure consists of macroscale tilt ratchet equipped with a reentrant tip and microscale grooves that decorated on the whole surface along a specific orientation. Distinct from conventional design requiring the elimination of microgrooves-like surface deficiency, we demonstrated that the microgrooves of dual-scale structure play a key role in delaying or promoting the local flow of liquids, tuning of which could even enable liquids select different spreading pathways. This study provides a new insight for developing surfaces with tunable multi-scale structures, and also advances our fundamental understanding of the interaction between liquid spreading dynamics and surface topography.

NOMA Empowered Energy Efficient Data Collection and Wireless Power Transfer in Space-Air-Ground Integrated Networks

As the sixth generation network(6G)emerges,the Internet of remote things(IoRT)has become a critical issue.However,conventional terrestrial networks cannot meet the delay-sensitive data collection needs of IoRT networks,and the Space-Air-Ground integrated network(SAGIN)holds promise.We propose a novel setup that integrates non-orthogonal multiple access(NOMA)and wireless power transfer(WPT)to collect latency-sensitive data from IoRT networks.To extend the lifetime of devices,we aim to minimize the maximum energy consumption among all IoRT devices.Due to the coupling between variables,the resulting problem is non-convex.We first decouple the variables and split the original problem into four subproblems.Then,we propose an iterative algorithm to solve the corresponding subproblems based on successive convex approximation(SCA)techniques and slack variables.Finally,simulation results show that the NOMA strategy has a tremendous advantage over the OMA scheme in terms of network lifetime and energy efficiency,providing valuable insights.

Balloon-occluded retrograde transvenous obliteration for treatment of congenital intrahepatic portosystemic venous shunt:A case report

Congenital intrahepatic portosystemic venous shunt(CPSVS), a rare vascular malformation, has been described in both children and adults and can lead to severe neurophysiological complications. However, a standard therapeutic protocol for CPSVS has not been elucidated. With the advantage of minimally invasive techniques,transcatheter embolization has been used to treat CPSVS. The condition is challenging to manage, especially in patients with large or multiple shunts, through which rapid blood flow can cause ectopic embolism. Here, we describe a case of CPSVS with a large shunt that was successfully treated with balloon-occluded retrograde transvenous obliteration with interlocking detachable coils.

An Energy-Efficient UAV Deployment Scheme for Emergency Communications in Air-Ground Networks with Joint Trajectory and Power Optimization

The space-air-ground integrated network(SAGIN)has gained widespread attention from academia and industry in recent years.It is widely applied in many practical fields such as global observation and mapping,intelligent transportation systems,and military missions.As an information carrier of air platforms,the deployment strategy of unmanned aerial vehicles(UAVs)is essential for communication systems’performance.In this paper,we discuss a UAV broadcast coverage strategy that can maximize energy efficiency(EE)under terrestrial users’requirements.Due to the non-convexity of this issue,conventional approaches often solve with heuristics algorithms or alternate optimization.To this end,we propose an iterative algorithm by optimizing trajectory and power allocation jointly.Firstly,we discrete the UAV trajectory into several stop points and propose a user grouping strategy based on the traveling salesman problem(TSP)to acquire the number of stop points and the optimization range.Then,we use the Dinkelbach method to dispose of the fractional form and transform the original problem into an iteratively solvable convex optimization problem by variable substitution and Taylor approximation.Numerical results validate our proposed solution and outperform the benchmark schemes in EE and mission completion time.

Application of MR Technology in Teaching:A Case Study of UAV Agriculture&Forestry Plant Protection Curriculum

In order to solve the problems of insufficient training equipment,relatively lack of curriculum resources and single teaching means in the teaching of UAV(unmanned aerial vehicle)applied technology major,this paper studies the application of MR(Mixed Reality)in UAV applied technology major teaching,with the teaching of UAV agriculture&forestry plant protection curriculum as the carrier.The study will solve the pain points in teaching,improve the teaching ability and teaching information level,and increase the talent training quality of UAV,agriculture&forestry plant protection and related majors.Furthermore,it will create a protective,interactive,remote and scalable teaching experience for stu-dents,which can improve the teaching effect and reduce the teaching cost.

Evaluation of Water Resource Potential in Anhui Province Based on Allocation Model

The nature of water resources can be divided into four categories:water for life,water for agriculture,water for industry,and water for ecology.On this basis,the regional right allocation model for water resources is built,and to make the model more operable,we calculate the weight of the key factors of model(four different types of water use:life,agriculture,industry,ecology),using analytic hierarchy process(AHP).Finally,based on the amount of available water resources in Anhui Province,we evaluate the water resource potential in Anhui Province according to the principle of rational allocation.

Causes for Middle Income Trap and Recommendations for China's Leaping Paths

The middle income trap is an objective challenge faced in the development of the economy. There is provision in both the amount and time. It is worth studying why some Latin American countries have fallen into this trap for decades. This paper analyzed the causes for the middle income trap of Latin American economies. On this basis,it came up with recommendations for China's leaping paths,including accelerating the structural reforms on the supply front to promote industrial transformation and upgrading,deepening the reform and increasing the efficiency with institutional innovation as the core,protecting legitimate property rights,reforming the income distribution,combining accurate poverty alleviation,narrowing the gap between the rich and the poor,performing administration according to laws,vigorously developing education,expanding the opening up,and keeping sustainable growth,so as to successfully leap over the middle income trap.

METTL1 promotes colorectal cancer cell proliferation by attenuating CHEK2-induced G1/S phase arrest

Colorectal carcinoma(CRC),the third most commonly diagnosed cancer,accounts for 9.7%of all newly diagnosed cancer cases and 9.4%of cancer-related deaths globally.1 Recent studies have demonstrated that post-transcriptional RNA modifications,such as N^(6)-methyladenosine,N^(5)-methylcytosine,and N^(7)-methylguanosine,play critical roles in the regulation of mRNA stability and translation,primary microRNA processing,and lncRNA-protein complex that contributes to the progression of human cancer.

Design a Hybrid Energy-Supply for the Electrically Driven Heavy-Duty Hexapod Vehicle

Increasing the power density and overload capability of the energy-supply units(ESUs)is always one of the most challenging tasks in developing and deploying legged vehicles,especially for heavy-duty legged vehicles,in which significant power fluctuations in energy supply exist with peak power several times surpassing the average value.Applying ESUs with high power density and high overload can compactly ensure fluctuating power source supply on demand.It can avoid the ultra-high configuration issue,which usually exists in the conventional lithium-ion battery-based or engine-generator-based ESUs.Moreover,it dramatically reduces weight and significantly increases the loading and endurance capabilities of the legged vehicles.In this paper,we present a hybrid energy-supply unit for a heavy-duty legged vehicle combining the discharge characteristics of lithium-ion batteries and peak energy release/absorption characteristics of supercapacitors to adapt the ESU to high overload power fluctuations.The parameters of the lithium-ion battery pack and supercapacitor pack inside the ESU are optimally matched using the genetic algorithm based on the energy consumption model of the heavy-duty legged vehicle.The experiment results exhibit that the legged vehicle with a weight of 4.2 tons can walk at the speed of 5 km/h in a tripod gait under a reduction of 35.39%in weight of the ESU compared to the conventional lithium-ion battery-based solution.

Clinical study using mesenchymal stem cells for the treatment of patients with severe COVID-19

The coronavirus disease 2019(COVID-19)caused by SARS-CoV-2 was identified in December 2019.The symptoms include fever,cough,dyspnea,early symptom of sputum,and acute respiratory distress syndrome(ARDS).Mesenchymal stem cell(MSC)therapy is the immediate treatment used for patients with severe cases of COVID-19.Herein,we describe two confirmed cases of COVID-19 in Wuhan to explore the role of MSC in the treatment of COVID-19.MSC transplantation increases the immune indicators(including CD4 and lymphocytes)and decreases the inflammation indicators(interleukin-6 and C-reactive protein).High-flow nasal cannula can be used as an initial support strategy for patients with ARDS.With MSC transplantation,the fracrion of inspired O2(Fi02)of the two patients gradually decreased while the oxygen saturation(Sa02)and partial pressure of oxygen(P02)improved.Additionally,the patients9 chest computed tomography showed that bilateral lung exudate lesions were adsorbed after MSC infusion.Results indicated that MSC transplantation provides clinical data on the treatment of COVID-19 and may serve as an alternative method for treating COVID-19,particularly in patients with ARDS.

Calculation of fire extinguishment time with water mist in an enclosed room

The fire extinguishment time is a major factor to evaluate the efficiency of fire extinguishment with water mist. In this paper the fire extinguishment time with water mist in an enclosed room is calculated. Before adding water mist, the chemical kinetics plays the role in combustion, where a dimensionless math model is established by us-ing the Semenov theory. After adding water mist, the diffusion plays the role instead. Then another math model containing water mist and dominated by oxygen concentration is established. The fire temperature is integrated from Tm to extinguishment temperature TB and the extinguishment time can be obtained. The calculated values are compared with the experimental data under different conditions. The results show that this model can predict the fire extinguishment time accurately. Besides, this model also can be used to determine the critical water mist flux and evaluate which fire extinguishment mechanisms dominate the extinguishment.

Bio-inspired Leg Design for a Heavy-Duty Hexapod Robot

The leg structure is crucial to the legged robot's motion performance.With the size and load of the legged robot increasing,the difficulty of leg design increases sharply.Inspired by biomechanics,this paper proposes a leg design approach based on effective mechanical advantage(EMA)for developing the heavy-duty legged robot.The bio-inspired design approach can reduce the demand for joint actuation forces during walking by optimizing the ratio relationship between the joint driving force and ground contact force.A dimensionless EMA model of the leg for the heavy-duty legged robot is constructed in this paper.Leg dimensions and hinge point locations are optimized according to the EMA and energy-optimal criterion.Based on the optimal leg structure,an electrically driven tri-segmented leg prototype is developed.The leg's joint hinge points are located near the main support line,and the load-to-weight ratio is 15:1.The leg can realize a swing frequency of 0.63 Hz at the stride length of 0.8 m,and the maximum stride length can reach 1.5 m.