bluuebunny/crossref_metadata_2025 huggingface dataset:
Linear polarimetry for analysis of skin degenerative alterations
Authors: Ilyov S , Genova Ts , Troyanova P , Gisbrecht A , Avramov L
Published: May 2023

Investigation and characterization of the basic polarimetric characteristics on different cutaneous degenerative conditions (Syndrome of Raynaud, lupus, and psoriasis) histological samples was carried out to evaluate the potential for analysis of skin degenerative alterations. Stained and unstained histological samples from the different groups of degenerative conditions of the skin were histologically addressed and were used for polarimetric measurements. Diode laser linearly polarized beam at 635 nm was used for irradiation of the samples and polarimeter, working in the visible spectral range 400-700 nm was applied for polarimetric measurements. We will present the results of histology tissue slides evaluation through Stokes polarimetry in transmission geometry. These studies allow analysis of skin degenerative alterations in collagen anisotropic structuration in extracellular matrix and could be used as indicators of the tissue condition. Therefore, the present work would make possible the establishment of database with polarimetric features of degenerative skin conditions.
New vector type optical vortex structures in isotropic media
Authors: Slavchev V , Dakova A , Dakova D , Bozhikoliev I , Kovachev L , Biswas A
Published: May 2023

In the present work, the formation of vector-type vortex structures in isotropic media is studied. These vortices exist in the electric field components and generate a depolarization in the vector field of the laser spot. Their behavior is governed by a system of amplitude equations. Additionally, new solutions have been found that describe similar types of vortex structures in an optical fiber. The optical vortices admit only amplitude-type singularities. The vortex structures observed within the vector amplitude function have ring-like patterns. The variation of the intensities of the x and y components of the amplitude function along the axis of the fiber is investigated.
Scaling the mid-IR radiation at 7 μm - two-stage double-pass 195 MHz narrow-bandwidth DFG laser system
Authors: Stoychev L I , Baruzzo M , Suárez-Vargas J J , Cabrera H , Nikolov I P , Demidovich A A , Danailov M B , Vacchi A
Published: May 2023

We present a laser system based on difference frequency generation (DFG) to produce tunable, narrow-linewidth (<30 pm), and high-energy mid-IR radiation in the 6785 nm region. The system exploits nonlinear crystals (such as LiInS2, LiInSe2 and BaGa4Se7) and nanosecond pulses generated by single-frequency Nd:YAG and Cr:forsterite lasers at 1064 and 1262 nm, respectively. Various experimental configurations are used: single-pass and double-pass through the nonlinear crystal. Additional increments of the output energy can be obtained by performing two stage double-pass geometry.
Additive manufacturing of hydroxyapatite: effect of some stereolithography parameters on the dimensional accuracy of green, debinded and sintered parts with different geometries
Authors: Schrijnemakers A , Vertruyen B , Coibion D , Closset R , Hastir R , Boschini F
Published: May 2023

We report on the stereolithography printing of a hydroxyapatite powder dispersed in an acrylate-based resin with a focus on the influence of the laser power, the scanning speed and the layer thickness on the dimensional accuracy of the green, debinded and sintered parts and on the microstructural and mechanical properties of the sintered parts.
Numerical Simulation of the Propagation of Premixed Gas in a Pipe Flame Arrestor
Authors: Liu Duo , Sun Shaochen , Wang Lin
Published: May 2023

In this paper, a numerical model of the propagation process of premixed gas in a pipeline flame arrestor is established and solved. The numerical simulation results show that the flame propagation velocity and pressure variation curves of the propane-air premixed gas are the same as those of the ethylene-air premixed gas. The flame front and pressure oscillate periodically throughout the process, and the flame speed oscillates down when the flame front reaches approximately the middle and rear of the pipe. In contrast, the flame velocity versus pressure curve for the explosion of hydrogen-air premixed gases is quite different, with the flame propagating at an almost constant velocity in the initial stages, accelerating suddenly when the flame front reaches near the middle of the pipe, reaching a peak, followed by an accelerated decrease in flame velocity; at the middle and rear of the pipe, the flame once again propagates at a nearly constant velocity, and as the flame is quenched, the flame propagation velocity once again accelerates and decreases. The explosion pressures of the propane-air and ethylene-air premixed gases at each measurement point in the pipeline increase linearly with the initial pressure, and the explosion pressure appreciation is very close. The explosion pressure of hydrogen-air premixes increases significantly with increasing initial pressure, but the increase decreases slightly. The increase in initial pressure increases the flame propagation rate of the premixed gas, and the acceleration effect is significant.
Research on Output Voltage Self-Balance Control Method of Bipolar DC Distribution Grid for Renewable Energy Consumption
Authors: Wen Chuanxin , Yun Yang , Han Zhongxiu , Wang Yu , Huang Jun
Published: May 2023

Changes in the positive and negative DC loads of bipolar DC distribution grid cause the voltages of DC buses to deviate from the rated value, resulting in additional losses due to unbalanced current and affecting the reliable operation of the distribution grid. This paper proposes an output voltage self-balance control method based on a neutral-point-calmed triple active bridge (NPC-TAB) converter in a bipolar DC distribution grid. First, the topology and operating principle of NPC-TAB are introduced. Then the power model of the topology is deduced based on the phasor method. Based on the above analysis, an output voltage self-balance control method is proposed with the minimization of reactive power to achieve the self-balance of output voltage while controlling the minimization of reactive power of the converter. Finally, the simulation model is established in MATLAB/Simulink to verify the effectiveness of the optimal control method.
Application Research of PVT in Solar House R-CELLS
Authors: Ai Dengxin , Xu Ke , Wang Kun , Zhang Li , Yin Baoquan , Zhang Yi
Published: May 2023

The application of PVT (Photovoltaic-thermal) technology is discussed based on R-CELLS, which is a zero-energy solar energy house at Solar Decathlon China 2021. Combined with the actual data, the simulation model of the PVT system, which supplies domestic hot water and heating bathroom, is established in TRNSYS, and the performance evaluation of the whole year and heating season and economic analysis of the whole life cycle is carried out at the same time. Comparing and analyzing the system with or without auxiliary heating in the water tank, the simulation results show that the annual average electrical efficiency of the system is 15.35% and 15.52%, the annual average thermal efficiency is 3.36% and 9.52%, and the payback period is 13.87 years and 12.12 years. By increasing the number of PVT panels, 4 PVT panels can achieve zero energy consumption of the system, and the payback period of the PVT system can be reduced to 6.5 years after continuing to increase. The small-scale PVT system is systematically analyzed based on a case, and the importance of water tank auxiliary heating design and supply-demand matching design in the PVT energy supply system is found through data comparison, which has reference significance for the promotion of PVT building energy supply system in the future.
Research on the Fusion of Power Big Data Technology and Power System Simulation Calculation
Authors: Li BangYuan , Chang Rong , Yang ChuanXu , Mao ZhengXiong , Bao Fu , Tian Yuan , Zhang Hang
Published: May 2023

Power big data is the practice of big data concepts, methods, and technologies in the power industry. It is composed of structured data and unstructured data. It mainly involves power generation, transmission, transformation, and distribution. Power big data can reflect the macro-economy in real time, promote economic and social development, and improve the internal management level and economic benefits of the power industry enterprises. The integration of power big data technology and power system simulation calculation can update system analysis in real-time and provide new perspectives and methods for system analysis.
Loss Analysis of High-Speed Permanent Magnet Motor for Cordless Vacuum Cleaner
Authors: Bi Qing , Shao Dingguo
Published: May 2023

Compared with traditional permanent magnet motors, high-speed permanent magnet motors (HSPMM) have the advantages of fast dynamic response, high efficiency, high reliability, small size, etc. Therefore, HSPMM has been widely used in household and industrial fields, and the research on high-speed permanent magnet motors has become a hot spot in the motor industry. In this paper, the high-speed permanent magnet motor is applied to the cordless vacuum cleaner, and the calculation and analysis of the iron loss and copper loss of the high-speed permanent magnet motor are emphatically studied for the HSPMM used in the cordless vacuum cleaner.
Research on the Design and Verification of the Civil Aircraft Battery Integrated Control System
Authors: Wu Shanyong
Published: May 2023

This paper aims to study the integrated control technology of the civil aircraft battery system. The battery system is the backup power supply of the important DC (Direct Current) power equipment on the aircraft. As the last line of defense of the civil aircraft electrical power system, it plays an irreplaceable role in the safety of the aircraft. So, the research on battery system control is particularly important. This paper adopts forward design methods, such as capturing design requirements, functional decomposition, and integrated design, and proposes a relatively advanced battery-integrated control technology. This technology is verified by laboratory tests, on-aircraft ground tests, and flight tests. The test results show that this technology meets the design requirements and better solves the control problem of the battery system. It also has good social benefits and important reference significance for developing subsequent new aircraft types. It is of great significance to promote the rapid commercialization of civil aircraft in our country.
Nonlinear modelling and multi-stability characteristics of asymmetric hydro turbine governing system
Authors: Lai Xinjie , Li Dedi , Zong Yue , Huang Huimin
Published: May 2023

The asymmetric hydro turbine governing system (AHTGS) has been widely applied in engineering practice, yet the stability characteristics and nonlinear behaviours of AHTGS are seldom studied. Therefore, the authors are motivated to study the stability characteristics and nonlinear behaviours of AHTGS by using Hopf bifurcation theory. Firstly, the refined nonlinear mathematical model of AHTGS is constructed, which takes account of the nonlinear head loss in asymmetric penstocks. Subsequently, the multi-stability characteristics of AHTGS is revealed based on the refined nonlinear mathematical model by using stable domain. Then, the multi-timescale oscillation phenomenon is revealed, i.e. system dynamic response consists of two subwaves with different frequencies. Moreover, the relationship of the two subwaves and the system multi-stability is investigated. The result indicates that the two supercritical bifurcation lines are emerged and a two-timescale oscillation is generated. The stability of the two-timescale oscillation is determined by the two emerged stable domains. In addition, the cause of high-frequency and low-frequency subwaves has been verified as the natural hydraulic oscillation and hydraulic interference between the hydro turbine generating units, respectively. The overall stability of AHTGS is determined by the intersection area of the two stable domains, therefore the reasonable tuning of control parameters within the comprehensive stable domain is critical to maintain the stability of AHTGS.
Analysis of Transient Recovery Voltage of 500 kV Line Considering Current Limiting Reactor
Authors: Ren Hongtao , Zhang Ying
Published: May 2023

To limit the short-circuit current level, the method of series current, the limiting reactor is used to limit the short-circuit current, and the common access mode of the current limiting reactor is direct access. The series current limiting reactor can effectively limit the short-circuit current in 500kV power system, but after it is connected to the system, it will increase the transient recovery voltage steepness in case of a circuit breaker breaking fault and affect the normal breaking of the circuit breaker. Based on a 500 kV current limiter project, the influence of a lower limit current reactor on the recovery voltage of circuit breaker under different fault conditions is studied by using electromagnetic transient simulation software EMTP. The results show that the transient recovery voltage of the circuit breaker will exceed the standard value after the reactor is connected. When capacitors above 600nF are connected in parallel to the current limiting reactor, the transient recovery voltage could be limited to the standard range.
Analysis of Low Temperature Anti-Cracking Property of Epoxy Materials for Cable Intermediate Joints
Authors: Qiao Jian , Yin Li , Zhang Chong , Yang Wei , Gao Yanfeng , Li Zhenyu , Lu Yi , He Jianfei , Chen Youwen , Lv Yang , Wang Kun , Chen Yun
Published: May 2023

In this paper, multi-channel strain sensors are used to in-situ monitor the changes of strain with temperature under low temperatures for different stress angles in epoxy cladded metal inserts and the low temperature anti-cracking performances of the epoxy materials used for cable intermediate joint were analyzed. Compared with the foreign epoxy EP-0, the self-prepared toughed epoxy EP-1 has higher tensile strength, larger elongation at break and smaller modulus, showing a stronger toughness. The glass transition temperature of EP-0 and EP-1 epoxy materials are approximately the same. Besides, although the epoxy cladded metal inserts for EP-0 and EP-1 were both uncracked and intact when the temperature decreased from 0 to -70 °C, the strain and the stress at the stress angle R2 of EP-0 increased more rapidly with the decrease of the temperature than that of EP-1, which can be inferred that the cracking temperature of EP-0 is lower than that of EP-1. Thus, the low-temperature anti-cracking performance of self-made toughed epoxy material is better than that of commonly used foreign epoxy material.
A Dimensional Reduction Optimization Strategy for Line Voltage cascade Quasi-Z-Source Inverter Based on GRA-PCA-PSO
Authors: Li Zhiyong , Xi Wanting , Cao Yuan , Pu Shiping
Published: May 2023

Compared with traditional inverters, line voltage cascade quasi-Z source inverter (LVC-QZSI) has many advantages, but its power quality problems limit its wide application to some extent. In this paper, voltage ripple and power loss of LVC-QZSI are selected as the optimization objectives to build a multi-objective optimization model of LVC-QZSI. In the optimization process, it is found that the dimension of decision variables is too high, which belongs to a kind of large-scale multi-objective optimization problem. To solve this problem, this paper proposes the dimension reduction and optimization strategy of particle swarm optimization based on gray relation analysis and principal component analysis (GRA-PCA-PSO). GRA-PCA is used to realize the dimension reduction of decision variables, and then PSO based on information entropy is used to optimize the multi-objective optimization model after dimension reduction. Finally, the original optimization parameter values are derived from the eigenvalue matrix obtained from PCA. Compared with the traditional method of decision variable grouping and co-evolution, it reduces the calculation cost and improves the optimization accuracy. Finally, we verify the reliability of the algorithm.
The Impact on Absolute Along-Track Station-Keeping of Coordinate Additional Perturbation
Authors: Liu Qi , Zhao Shuge , Li Xiaoyu , Deng Xuelei , Zhang Zhen
Published: May 2023

The purpose of the current paper is to investigate how the coordinated additional perturbation influences the along-track station-keeping. The absolute along-track station-keeping method has been developed and can achieve high-precision maintenance when the orbits are near-pole in previous studies. The accuracy of station-keeping deteriorates when the orbits are not near-pole. The reason is that the additional perturbation of the Mean Equator Mean Equinox of the J2000.0 (J2000) coordinate system makes a great difference in the absolute station-keeping between different inclinations, which has not been studied before. First, the impact factor model is constructed to measure the influence of the coordinate additional perturbation. Second, the impact factors of different orbits are analyzed and it is found the impact factor increases gradually with the decrease of inclination. Third, how impact factor indicating the accuracy of station-keeping is investigated and coordinate systems are recommended based on the impact factors. Finally, the numerical simulations of station-keeping in the J2000 coordinate system and True Equator Mean Equinox (TEME) coordinate system are carried out. Results show that the TEME coordinate system is more advantageous in the station-keeping mission than J2000 when the orbits are not near-pole.
PID control and simulation of moving mass quadcopter UAV
Authors: Xu Tianfang
Published: May 2023

Based on the quadrotor drones we see today, in this paper, a mass center control mechanism installed on the body is proposed to control the flying attitude of the UAV. The moving mass control technology changes the position of the center of mass by moving the position of the mass block of the system. The technology is used in a wide range of aircraft, from drones to gravity satellites. The moving mass center mechanism mentioned in this paper is composed of three sliding blocks that can slide along the spatial axes and are controlled by a linear motor. The linear motor controls the slider movement to generate the torque along different channel directions, to realize the attitude change of the UAV. In this paper, through the kinematics analysis of the quadrotor UAV, combined with PID control and simulation, finally realized the modification of the UAV’s flight attitude with moving mass technology. The simulation results show that the quadrotor UAV can complete the attitude conversion stably with the help of the mass center control mechanism.
Fatigue life assessment of fuselage panel modification based on flight measurement
Authors: Liu Fu wen , Huang Bo , Xiao Ying Chun , Yang Yu
Published: May 2023

During the modification of the aircraft fuselage panel, the fatigue performance of the structure changes. To ensure the safety and reliability of commercial aircraft, the fatigue life assessment of the modified structure is required. In this paper, the detailed fatigue rating method was used for fatigue assessment. The strain information of the modified structure during the flight was obtained by installing fiber Bragg grating sensors. Through the finite element analysis, the fatigue critical parts were determined and the measured data before modification were converted into the data after modification. The detailed fatigue ratings of the fatigue critical parts were calculated. The fatigue life of the critical parts was evaluated based on the linear fatigue damage cumulative rule. According to the results, the most critical part was determined, which provides a basis for the determination of the modification plan of the fuselage panel.
Helicopter Load Factor Limit Protection Method Based on A Predictive Control Algorithm for Vertical Maneuvering
Authors: Liu Xiaoxiao , Li Pan , Zhu Zhenhua
Published: May 2023

The purpose of this paper is to solve the problem of the helicopter load factor limit exceeding caused by inappropriate pilot control in vertical maneuvering flight. Through the collective stick control power restriction, an load factor limit protection method based on a load factor predictive algorithm is proposed. First, the load factor prediction is realized by the change rate of the collective stick position given by the actuator and the control derivative of the collective stick position to vertical acceleration, and then the vertical control power is restricted according to the predicted load factor, so as to achieve the purpose of helicopter load factor protection.
Application and research of linear ADRC in Buck converter
Authors: Shen Wang , Zhang Xieyan , Xie Yixue
Published: May 2023

This paper takes PWM modulated DC-DC Buck converter as the object to improve the traditional LADRC method. Firstly, the LESO module directly feeds back an error differential signal, which can improve its disturbance observation performance. Secondly, the disturbance differential term is imported to the LESO module to enhance the observation speed of disturbance. Finally, a first-order inertial link is joined to the disturbance estimation channel to suppress the high-frequency noise disturbance caused by the increase in observation bandwidth. By analyzing the frequency response characteristic curves of the improved LADRC method and the conventional LADRC method, it can found that improved LADRC method has preferable disturbance resistance performance. Using Simulink model, experimental consequence confirm the availability and correctness of the optimization method.
Distributed rotorcraft coupling modal parameters influence analysis
Authors: Zhang Guibao , Zhu Yan , Wang Siwen , Sun Fengnan , Cheng Qiyou , Feng Zhizhuang
Published: May 2023

In order to explore the influence mechanism of different parameters on Multi-rotor aircraft dynamic characteristics, Hamilton principle and the theory of medium deformation beam were used to derive the rotors/nacelle/wing coupling structure dynamic equation, and a solution method suitable for the analysis of coupled modal was established. By using literature as an example calculate rotor and wing modal, the error is less than 5% compared with the experimental results in the literature, indicating that the coupling model in this paper is accurate and effective. On this basis, the influences of, nacelle offset, rotor collective pitch, blade center of mass on the coupling modal are studied.
Research on Asynchronous Information Fusion Technology of the Distributed Active/Passive Imaging Detection System
Authors: Gu Yifan , Kang Youwei , Fang Zeyuan , Liao Xin , Tang Shanjun
Published: May 2023

In the process of target cooperative tracking of the distributed multi-imaging detection system, aiming at the problem of asynchronous measurement information from different detectors, a distributed Asynchronous and Heterogeneous Information Matrix Fusion algorithm based on the Cubature Kalman Filter (CKF-AHIMF) is proposed. According to the Local Detector Driven Communication (LDDC) method and CKF nonlinear mapping, IMF distributed fusion algorithm is generalized into nonlinear, asynchronous, and heterogeneous cases to integrate the information from a multi-imaging detection system and to obtain global high-precision target trajectory. Through the digital simulation, it is verified that the CKF-AHIMF algorithm under the LDDC method proposed in this paper is more effective and has higher tracking accuracy than other distributed fusion algorithms in dealing with the problem of target cooperative tracking under asynchronous information from local imaging detectors, which is also valid to implement in precision detection and guidance system.
An Improved Mickens Iterative Method for Nonlinear Aeroelastic analysis of Airfoils with an External Store
Authors: Chen Feixin , Deng Jianxin , Ding Zhenghao , Li Weihua , Xiao Suhua
Published: May 2023

This paper aims to propose a modified Mickens iteration method for analyzing the flutter stability of the nonlinear airfoil with an external storage system. Unlike the regular Mickens approach, the modified form is established by substituting previous frequencies of the limit cycle oscillation (LCO) into unknown ones. Then the algebraic equations governing the LCO amplitude and frequency could keep linear, which might improve the calculation efficiency. The numerical example shows the LCOs obtained easily and accurately. Furthermore, the phase planes of the LCOs are investigated with the wind speed varying. The approach could be applicable to investigate mechanical systems with complicated nonlinearities.
Experimental Research on Vibration Dynamics Performance of Type B Metro Vehicles
Authors: Chen Guanghu , Gong Yanqing , Xie Lei , Liu A’kui , Chen Shaoqiang
Published: May 2023

In recent years, due to the acceleration of urban rail transit construction, the cumulative length of urban rail transit lines in China has also continued to grow. As one of the typical representatives of urban rail transit, the subway is an excellent choice for the general public due to its energy saving, environmental friendliness, large transportation capacity, and high punctuality rate. However, this also imposes stricter requirements on the operational safety and smoothness of subway vehicles. The vibration generated by subway vehicles in operation will affect the riding experience of passengers and subway vehicles to varying degrees. Vibration research is an important part of the research on rail transit vehicles. In this paper, a dynamic performance test of a B-type subway vehicle is carried out. According to GB/T5599-2019 and other standards, the operation safety and stability of the vehicle under no-load and overloaded loads and the vehicle vibration characteristics are studied, which provides reliable experimental data for the subsequent research of the vehicle.
Research on optimization of photovoltaic capacity in the multi-energy complementary power generation system
Authors: Zhang Bozhi , Wei Zirui , Li Kun , Zhou Lixia
Published: May 2023

Multi-energy complementary power generation (MEPG) technology is one of the effective utilization means of renewable energy generation. In this paper, a MEPG system is proposed, which includes a photovoltaic (PV) subsystem and ISCC (solar integrated combined cycle) subsystem. To optimize the capacity of the PV subsystem, the dynamic simulation of the MEPG system is carried out under the condition of operating for 2 hours continuously. By stabilizing the output power of the MEPG system at the target value during the operation, the relatively suitable capacity of the PV subsystem is obtained. The results show that for the MEPG system, the PV subsystem should be less than the capacity of the solar field in the ISCC subsystem.
Analysis Service Process of Aircraft Turnaround Operations by Petri Net
Authors: Zhang Shu-qin , Jiang Wei , Yang Ning , Liu Ying
Published: May 2023

Airport collaborative decision-making has put forward higher requirements for aircraft turnaround operations. In order to improve the efficiency of aircraft turnaround operations, this paper improves the Petri net model based on the characteristics of MATLAB language. It gives the specific steps to analyze the influence of aircraft turnaround operations period on the apron flight viable service route. The experimental analysis shows that the change in passenger cabin cleaning, catering, and air bridge disconnecting within the routine service time does not affect the number of viable service routes and critical operations of aircraft turnaround service. Suppose the time of four operations, the bridge connecting, water clearing, passenger deboarding, and water filling, are respectively set in the interval [1.43, 1.98], [8, 8.7], [10.5, 11] and [8.1, 9.9], the number of viable service routes will only achieve two values. In that case, the bigger one is 4.7543 * 1076 with the 72% generating probability. The other is 3.5715 * 1076, which is 3.11 * 104 times as many as the minimum value obtained by the regular value interval of four operations, improving the quality of the minimum number of viable service routes. The results indicate that setting the time of some aircraft turnaround operations within a reasonable range will improve the number of viable service routes.
Analysis method and application of rotor dynamic balance test for large hydropower units
Authors: Yang Xingfu , Zhang Haiku , Li Guiji , Fu Zhiqi , Tan Xiaoxia , Chen Lei
Published: May 2023

The spindle runout of unit 2 in a hydropower plant seriously exceeded the standard during the startup test, and its main frequency was consistent with the conversion frequency, which did not meet the startup test acceptance specification. Through the analysis of the variable speed test data of the unit, it is judged that the reason for the excessive runout is the mass imbalance of the generator rotor, which affects the vibration of the shafting and the frame. A dynamic balance test analysis method is proposed to determine the counterweight weight and orientation, which is the same centrifugal force with the equivalent in the state. In this method, the weight of the trial counterweight and the total unbalanced mass is calculated by using the trial counterweight empirical formula and dynamic balance equation respectively, and the second counterweight test is carried out after calculation. Through the application in unit 2 of the power plant, the serious problem of excessive runout of the unit can be completely solved. The analysis method of the rotor dynamic unbalance test for large hydropower units proposed in this paper can provide a technical reference for similar problems.
Design and verification of VCU system based on ISO26262
Authors: Wang Xiyang , Li Hongpeng , Xi Wenxia , Zhang Dianming , Guo Wei
Published: May 2023

According to ISO26262 standard, the functional safety analysis of the pure electric vehicle’s concept stage of Vehicle Control Unit (VCU) was carried out. From this, the safety goals and ASIL levels of the VCU are determined. According to the safety analysis method, the functional safety requirements of the VCU at the vehicle level are obtained. At the hardware architecture level, the functional safety design of the VCU’s microcontroller module, storage module, and power supply module is carried out to meet the functional safety development requirements. Carefully consideration of software failures that may occur during VCU software development. These include software architecture design, safety-critical code/program flow monitoring, change management, and safety-critical variables. The fault injection test of the VCU demonstrates the feasibility of this technology.
Visual/inertial odometry with tight coupling of multi-bit pose information
Authors: Jie Xiaohan , Liu Ning
Published: May 2023

To address the problem that the loosely coupled frame pose scale needs to be initialized manually, making the subsequent algorithm less accurate and less real-time, while the tightly coupled OKVIS does not include closed-loop detection and map building, an adaptive vision/inertial odometry method with tightly coupled multi-bit pose information is proposed, incorporating optimized map points to provide more accurate data for the subsequent algorithm, with repositioning, closed-loop detection and global a complete visual/inertial odometry system with repositioning, closed-loop detection, and global posture map optimization functions. The adaptive vision/inertial odometry with tightly coupled multi-location posture information is experimentally validated to have better real-time performance, accuracy, and robustness than the loosely coupled algorithm.
Optimization of Diversion Device and Experiment on Air-assisted Sprayers in Orchards
Authors: Fan Shaohuan , Gao Gaili , Shen Hui
Published: May 2023

In order to improve the velocity distribution of the airflow field generated by the air-assisted sprayer in the orchard, a flow field distribution model of the sprayer air delivery system based on CFD simulation is designed. The airflow field distribution of the air-assisted operation is obtained through FLUENT simulation. The calculation domain includes the internal flow field and external flow field of the fan. The simulation result guides the optimal installation angle of the flow guide device. The installation angle of the upper deflector is 50°, and the installation angle of the lower deflector is 25°, so that the airflow generated by the air-assisted sprayer is mainly concentrated at a height of 0.7–3 m when it reaches the pear tree canopy. The installation angle of the inner deflector 1 and inner deflector 2 is 35°, the installation angles of the inner deflector 3, inner deflector 4, and inner deflector 5 are all 45°, and the average speed is increased by 18.81% in the range of height 1.6–2.4 m. A velocity distribution experiment is designed to measure the airflow velocity to verify the accuracy of the CFD simulation model. The simulation value is basically consistent with the measured value, which provides guidance for optimizing the parameters of the flow guide device.
Robot path planning by integrating improved A* algorithm and DWA algorithm
Authors: Jin Mengqi , Wang Hanxi
Published: May 2023

Traversing many nodes, low search efficiency, path slanting through obstacles, many path redundancy points, and the inability of dynamic real-time obstacle avoidance are all typical problems of A* algorithm. In this paper, A robot path planning method combining improved A* algorithm and DWA algorithm is proposed.The ratio of the distance between the current point and the starting point and the target point is introduced into the heuristic function, and the search efficiency is improved through the optimized heuristic function; the neighborhood search principle is simplified to 5-neighborhood search, and the nodes adjacent to obstacles are deleted to reduce the traversal nodes while avoiding diagonal penetration of obstacles; redundant node improvement method is used to reduce the degree of path transition; finally the path key points of the improved A* algorithm are extracted and DWA algorithm is fused to realize the robot to avoid unknown obstacles. Finally, experiments are carried out on Matlab to prove the feasibility of the new algorithm.
Research on dynamic perfusion control technology of 3D printed tissue vascular network
Authors: Wang Jun-jie , Zhang Li-ming , Li Song
Published: May 2023

In order to solve the problem that the medium cannot be supplied accurately during the perfusion culture of the vascular network in large-volume 3D printing tissue, a perfusion control technology was studied by designing and building an in vitro perfusion and monitoring platform with feedback regulation. First, a large-volume vascular network of hydrogel material was fabricated by 3D bioprinting technology as the experimental object of perfusion. Then we designed and built the dynamic perfusion device and the monitoring equipment in the perfusion process independently and applied the real-time flow calibration control technology on this basis. Finally, the accuracy of the flow real-time calibration control technology was verified through the perfusion experiment of the large-volume vascular network. The results showed that the error rate between the actual flow rate and the preset flow rate increased gradually with the decrease of the preset flow rate of medium perfusion. When the preset flow is 3 mL/min, the error rate between them is as high as 19.33% without the application of flow calibration control technology. The dynamic perfusion device can reduce the average error rate between the two from 8.1% to 0.4% after applying real-time flow calibration control technology, which proves that the device can cultivate a large-volume vascular network with high-precision perfusion after the application of real-time flow calibration control technology.
Analysis and Multi-target Optimisation of the Characteristics with Stepped Cavity of the Hybrid Bearing
Authors: Shen Yu , Pan Zhenhua , Liu Haijiang
Published: May 2023

In this paper, the peak pressure, stiffness, flow rate, and temperature rise of the oil film in the stepped cavity of the hybrid bearing are investigated. The pressure and flow equations for the central section of the stepped cavity and the axial section of the deep and shallow cavity are derived using the simplified Navier-Stokes equations and the boundary conditions of a liquid bearing. Using the control variable method, the influence of the geometrical parameters of the stepped cavity and the process parameters on the oil film characteristics was simulated, and the correctness of the pressure and flow equations was verified. The results show that: the spindle speed is positively correlated with the peak oil film pressure and flow rate; the oil film thickness is negatively correlated with the peak oil film pressure and positively correlated with the flow rate; the depth and width of the shallow cavity are correlated with the peak oil film pressure, but the correlation with the flow rate is low; the maximum error between the theoretical calculation and the simulation analysis is less than 7.3%. The pressure equation and the flow equation are used to establish the objective function with the maximum oil film stiffness, load-bearing capacity, and minimum temperature rise, and the ideal point evaluation function method is used to do a multi-target optimization design to optimize the ladder cavity and obtain the optimal oil cavity geometric parameters. And an 8.75% increase in peak pressure and a 4.1% reduction in temperature rise for the same process parameters.
Detection of warning signal of particulate emission on the basis of fixed threshold in real-time using a lidar system
Authors: Rutigliano N. , Martellucci L. , Puleio A. , Rossi R. , Wyss I. , Gaudio P.
Published: May 2023

Monitoring pollutant emissions in an urban area is of primary importance in order to guarantee high levels of human health (by reducing the impact of respiratory diseases on urban inhabitants) and good preservation of objects (such as historical sites or buildings). The European Environment Agency (EEA) has established that the maximum concentration of PM2.5 concentration for long-term exposure is 10 μg/m3. By measuring the light that has been backscattered by atmospheric particulates, the lidar technique seems to be a valid method to provide a warning signal when a particulate concentration threshold is exceeded. In addition, the lidar system can also provide information about the distance at which the particulate threshold is exceeded. In this research measurements of traffic-originated particulate in the area near the University of Rome “Tor Vergata” is analysed at different times on a weekday to obtain continuous monitoring of its backscattering coefficient, values of particulate concentration and details about time and distance from the lidar system at which a warning signal is provided. The University of Rome “Tor Vergata” is in an area where traffic is very heavy, so high pollutant concentration values are to be expected.
Design and characterization of AmLi neutron sources for the LZ experiment
Authors: Sazzad A.B.M.R. , Busenitz J. , Piepke A. , Poudel S. , Trewin H. , LeViness A.
Published: May 2023

In this paper we describe the development, testing, and characterization of three
low-emission rate AmLi neutron sources. The sources are used to calibrate the nuclear recoil
response of the LUX-ZEPLIN (LZ) dark matter experiment. The sources' neutron emission rate was
measured using 3He proportional tubes. The sources' gamma emissions were
characterized using a high-purity germanium (HPGe) detector. Source-validated Geant4
Monte Carlo simulations allowed to calibrate the Ge and neutron detectors' responses.
Resveratrol loaded native silk fiber-sericin hydrogel double interpenetrating bioactive wound dressing facilitates full-thickness skin wound healing
Authors: Li Yanwei , Wang Susu , Li Yurong , Zhang Guozheng , Wu Tangfeng , Wei Yongkang , Cao Xinyu , Yan Hui , Liang Peisheng , Yan Zihan , Guo Yanan , Zhang Yeshun
Published: May 2023

Wound repair is challenging for traditional wound dressings. New bioactive dressings need to be developed urgently. Herein, we reported a highly bioactive silk protein wound dressing (SPD) with natural silk fiber-sericin hydrogel interpenetrating double network structure, which combines the dual characteristics of natural silk and sericin hydrogel. Silk fiber scaffolds were secreted directly from silkworms bred by regulating their spinning behaviors. Sericin in SPD is obtained by dissolving silkworm cocoons at high temperature and high pressure, while it remains intact activities to self-assemble a hydrogel. To explore the effect of SPD, we first systematically evaluated its physicochemical properties and biological activities in vitro. The SPD exhibits high porosity, prominent mechanical strength, pH-responsive degradability, and excellent anti-oxidation and cell compatibility. Besides, SPD can load and maintain long-term drug release. Based on the satisfactory performance of SPD in vitro, effective in vivo treatment was achieved in a mouse full-thickness wound model, as demonstrated by a significantly accelerated wound healing process, promote the regeneration of hair follicles and sebaceous glands, increased expression of vascular endothelial growth factor, and reduced inflammation. Further, resveratrol was loaded into SPD to enhance the effects of anti-oxidation and anti-inflammation for wound healing. Our investigation shows that SPD with excellent physicochemical and biological properties applied in a murine full-thickness skin wound model resulted in remarkable and efficient acceleration of healing process, which may inspire the design of new, effective, and safer medical materials for tissue regeneration.
Accounting for fuel in fire danger forecasts: the fire occurrence probability index (FOPI)
Authors: Di Giuseppe Francesca
Published: May 2023

A new fire danger index is proposed to overcome one of the most important limitations of current fire danger metrics. The fire occurrence probability index (FOPI) combines the Canadian fire weather index (FWI) with remote observations of vegetation characteristics to better predict landscape flammability. The FOPI is designed to improve fire danger predictions in all fuel-limited environments where fire is driven by the short-term drying of intermittently-available fuel. The FOPI considerably outperforms the FWI in arid biomes while remaining comparable to the FWI where fuel is abundant.
Asymptotic expansions for field moments of bound states
Authors: Forbes G W , Alonso Miguel A
Published: May 2023

Asymptotic expansions are presented for the moments of bound states in one-dimensional anharmonic potentials. The results are derived by using the stable aggregate of flexible element (SAFE) method and include only the first non-zero wave-related correction to the familiar semi-classical approximation. Application to a couple of widely studied potentials that do not permit closed-form solutions is used to demonstrate surprising accuracy even in cases that are far from any asymptotic limit. We explore the absence of alternate terms in the asymptotic expansions as a way to explain the accuracy of the end results. Those results are expressed as definite integrals with integrands involving the parameter used in the SAFE method to control the extent of the associated elemental field contributions. Importantly, the integrals themselves are shown to be precisely independent of that parameter. Further, although the derivation proceeds by way of an asymptotic expansion for the wavefield that involves the associated classical motion, those entities do not appear in the end results which are expressed in terms of just the potential function and its first four derivatives.
Finger gesture recognition with smart skin technology and deep learning
Authors: Ben-Ari Liron , Ben-Ari Adi , Hermon Cheni , Hanein Yael
Published: May 2023

Finger gesture recognition (FGR) was extensively studied in recent years for a wide range of human-machine interface applications. Surface electromyography (sEMG), in particular, is an attractive, enabling technique in the realm of FGR, and both low and high-density sEMG were previously studied. Despite the clear potential, cumbersome electrode wiring and electronic instrumentation render contemporary sEMG-based finger gestures recognition to be performed under unnatural conditions. Recent developments in smart skin technology provide an opportunity to collect sEMG data in more natural conditions. Here we report on a novel approach based on soft 16 electrode array, a miniature and wireless data acquisition unit and neural network analysis, in order to achieve gesture recognition under natural conditions. FGR accuracy values, as high as 93.1%, were achieved for 8 gestures when the training and test data were from the same session. For the first time, high accuracy values are also reported for training and test data from different sessions for three different hand positions. These results demonstrate an important step towards sEMG based gesture recognition in non-laboratory settings, such as in gaming or Metaverse.
Many-body spin rotation by adiabatic passage in spin-1/2 XXZ chains of ultracold atoms
Authors: Dimitrova Ivana , Flannigan Stuart , Kyung Lee Yoo , Lin Hanzhen , Amato-Grill Jesse , Jepsen Niklas , Čepaitė Ieva , Daley Andrew J , Ketterle Wolfgang
Published: May 2023

Quantum many-body phases offer unique properties and emergent phenomena, making them an active area of research. A promising approach for their experimental realization in model systems is to adiabatically follow the ground state of a quantum Hamiltonian from a product state of isolated particles to one that is strongly-correlated. Such protocols are relevant also more broadly in coherent quantum annealing and adiabatic quantum computing. Here we explore one such protocol in a system of ultracold atoms in an optical lattice. A fully magnetized state is connected to a correlated zero-magnetization state (an xy-ferromagnet) by a many-body spin rotation, realized by sweeping the detuning and power of a microwave field. The efficiency is characterized by applying a reverse sweep with a variable relative phase. We restore up to

50
%

of the original magnetization independent of the relative phase, evidence for the formation of correlations. The protocol is limited by the many-body gap of the final state, which is inversely proportional to system size, and technical noise. Our experimental and theoretical studies highlight the potential and challenges for adiabatic preparation protocols to prepare many-body eigenstates of spin Hamiltonians.