A portable electrocardiogram(ECG) monitoring device is designed for people with arrhythmia, myocardial ischemia, premature beats, and other heart diseases, and it is used for disease detection and prevention. In this paper, the RT1025 front-end ECG signal acquisition chip is studied first, followed by the development of a denoising infinite impulse response filtering algorithm for common noise such as electromyogram noise and 50 Hz power frequency interference, and the completion of program design for ECG data acquisition and communication. This equipment is stable in working condition, simple in data acquisition and control, and serves as a model for the design of portable ECG acquisition equipment. It is also important for the prevention and real-time monitoring of cardiovascular diseases.

In this study, a robot track equation is formulated to estimate the state and position of the robot based on a two-wheel differential drive model. Using the robot operating system(ROS) stack package, we design a robot structural model with seven joints and links, including a hydraulic robot body, a robot base, hydraulic motors, guide wheels, and lidar. The transformation of coordinate frames is shown over the Tf of ROS to obtain the coordinates of the robot's position. Because our robot does not possess an encoder and vision system, we use a two-dimensional (2D) planar lidar odometric model (RF2O). The planar motion estimation of the robot is performed by imposing the range flow constraint equation on consecutive lidar scan pairs. Then, the velocity of the lidar sensor and the real-time trajectory of the robot can be estimated. We also implement an autonomous navigation software system with functions such as navigation map building, navigation targeting, and multirobot management. We evaluate the accuracy of the system several times. Based on a comparative analysis of the difference in the data of assigned and navigated locations, the accuracy of robot navigation and position is found to satisfy the design requirements.

In this study, the spatial and temporal variation characteristics of holiday climate in Henan province are analyzed using the ground meteorological data (including daily maximum temperature, average relative humidity, precipitation, wind speed, and cloud-coverage rate) from 111 national meteorological observatories in Henan province for the past 30 years (1991—2020). The results show that the holiday climate index(HCI) of Henan reached a “suitable” or a more than “suitable” level from January to December, and the monthly variations present bimodal characteristics. In April to May and September to October, reaching the highest level “particularly suitable”. The Henan HCI indicates that the seasonal variations are the highest in spring and autumn, followed by summer, and the lowest in winter, the spatial distribution presents the “high in north and low in south” characteristics, and the seasonal distribution presents certain dimensional characteristics and obvious regional characteristics.

Herein, a class of Gross Pitaevskii (GP) equations with a trigonometric potential is studied. First, the Lax pair of GP equations is obtained. Second, the n-th Darboux transformation of the equations is provided and the n-soliton solution is obtained. Third, by selecting a zero seed solution, specific expressions of the single soliton solution and double soliton solution of the equations are obtained. Subsequently, Matlab is used to analyze the properties of the single and double soliton solutions, focusing on the influence of changes in parameters on the soliton.

The movement of hydrate and sand particles in submarine hydrate mining is still unclear. Therefore, in this study, the coupling method of the discrete element method (DEM) and computational fluid dynamics (CFD) is adopted to study the movement of hydrate and sand particles at the seabed. To verify the proposed method, the settling of spherical particles is simulated and compared with experimental findings. The feasibility of the proposed method is illustrated. Moreover, numerical simulations of a single sand particle and a single hydrate particle are performed using the DEM-CFD coupling method. Various particle positions, velocities, forces, and angular velocities are analyzed during particle movement. Simulation results show that the sand particles settle at the bottom of the container and collide when they reach the bottom while rotating simultaneously. The hydrate particles float upward without rotation. Finally, a numerical simulation of a particle swarm is performed in a closed container to show that the DEM-CFD coupling method can simulate complex flow with a large number of particles and analyze the particle force and movement at the microscopic scale. This study provides a reliable and effective method for multiphase flow research on hydrate and sand particles.

The effects of different volume fractions of dimethyl sulfoxide (DMSO) on plasmid and linear DNA denaturation were investigated using atomic force microscopy and dynamic light scattering. It was found that a low volume fraction of 1% DMSO solution can also induce local DNA denaturation, which can be directly observed by atomic force microscopy. Simultaneously, due to the limitations of plasmid DNA linking number and single-stranded DNA generation, atomic force microscopy and dynamic light scattering showed that DNA gradually forms a superhelix structure with an increase in the volume fraction of DMSO. The average particle size of pBR322 DNA, 5 000 base pair DNA, and λ-DNA decreased from about (474±10) nm, (554±11) nm, and (871±17) nm, respectively, in 0 DMSO solution to (257±8) nm, (282±18) nm, and (449±21) nm, respectively, in 10% DMSO solution.

Herein, esomeprazole magnesium trihydrate was prepared and its crystal form was controlled. Moreover, the properties of the product, such as the particle size distribution, were optimized. X-ray powder diffraction was used to characterize the crystal shape of the product. A two-dimensional online imaging system was employed to monitor changes in the crystal morphology during the reactive crystallization of esomeprazole magnesium trihydrate. A Marvin laser particle size analyzer was used to monitor changes in the particle size distribution. The effects of the crystallization temperature, reactant concentration, on the crystal form and mophorology of esomeprazole trihydrate magnesium were investigated. Results show that the crystallization mode of esomeprazole magnesium trihydrate is spherical and the crystallization temperature is the key factor affecting the crystal shape. The optimized reaction temperature was 25 ℃. Using the optimized process, drug particles of esomeprazole magnesium trihydrate with a fixed crystal shape, uniform particle size distribution, and large average particle size can be synthesized.

In this paper, the average quantum Fisher information was used to measure the entanglement characteristics of the system under the quadratic interaction. In addition, we considered the characteristics of the multi-body entanglement evolution of the system after adding the linear interaction term. The results showed that the multi-body entanglement of the spin system remains longer under the combined action of linear and nonlinear interactions. Moreover, we considered the entanglement process of the system under the influence of noise and found that the atomic system has a high degree of entanglement even in the presence of noise. This is extremely important for the application of quantum multi-body entanglement in quantum precision measurements and quantum communications.

This work studies an innovative technology for producing watermelon wine. Using watermelon as the main raw material, this wine was produced through mixed fermentation of multiple strains. A suitable fermentation process for watermelon wine was developed, and key operation steps were explained. The optimum proportion of inoculation amount of three strains was determined using single factor and orthogonal optimization tests (inoculation amounts: 250 mg/L of Zymaflore X5, 200 mg/L of Lalvin DV10, and inoculation amount 30 mg/L of Lactoenos SB3). Under the optimum strain ratio, the alcohol level in the watermelon wine produced herein was (8.77±0.15)%, total acidic concentration was(1.7±0.10) g/L, and amount of residual sugar was (3.97±0.15) g/L. The otal score of the produced watermelon wine's sensory evaluation was 92. The wine is orangish red, clear, and bright, having a unique aroma of fermentation and fruit, which is harmonious and smooth to the taste. This watermelon wine produced using the proposed technology has a broad market prospect as a health drink owing to its special features.

The stability of upwind schemes for first-order linear convection equations with variable coefficients is studied herein. The conditions to ensure the stability of upwind scheme are obtained using the energy inequality and freezing coefficient methods, and the accuracy of the stability analysis theory is verified via numerical experiments.

To solve the problems associated with the existing laser marking systems, such as difficulty in special-shaped marking, unclear and fuzzy characters, and poor graphics, a multiabnormity three-dimensional laser marking system is built herein. For the hardware, a segmented expanding shaft and a rotating expanding shaft are introduced based on a plane marking platform; moreover, an infrared focus-positioning system is used to realize three-axis linkage marking. For the software, to solve the issues that a laser-marking machine cannot automatically mark and engrave large-format and special-shaped workpieces, an improved marking processing software is designed and multimotor control is combined to realize one-time focus and defocus marking on plane and inclined surfaces. Based on the three-axis linkage hardware and marking software, the function of three-dimensional marking mode, such as inclined surface, segment difference, cylinder, cone, sphere, and extruded curved surface, can be completed. The experimental results show that the system can achieve the requirements of error-free and deformation-free marking on many types of special-shaped workpieces.

Focusing on the production method for mapping a high-resolution digital orthophoto and the problems that often occur in this production process, the key technology of producing high-resolution digital orthophoto maps from the practical perspective is proposed and the technical challenges and corresponding solutions are summarized using the 9600 km² 0.2 m resolution DMCⅢ digital aerial image data of Binzhou area and cluster image processing systems (such as Inpho, GEOWAY CIPS, and Pixel Factory) to produce 1:2000 digital orthophoto maps. Constructive suggestions on the acquisition and processing of high-resolution aerial images are carefully suggested. The proposals will help in improving the quality and efficiency of future projects in this field and will contribute to the fundamental surveying and mapping, which will benefit the economic development of China.