bluuebunny/crossref_metadata_2025 huggingface dataset:
Model of Hydrodynamic Friction in the Boundary Layer on an Inclined Flat Surface of an Aircraft
Authors: Klyuev Nikolay , Polyakov Konstantin , Klyuev Nikolay
Published: April 2022

An integral method for solving the problem of longitudinal flow of an inclined flat plate located in a stream of air flow is presented. As a result of the integration of the equations of motion over the thickness of the boundary layer, the two-dimensional problem becomes one-dimensional. The problem was solved numerically in the Mathcad software package. The graphs of the dependence of the thickness of the boundary layer and friction on the longitudinal coordinate at different angles of inclination of the plate are presented. The flow mathematical model can be used to determine the characteristics of two-dimensional boundary layers with arbitrary boundary conditions.
Simulation of Bee Aggregation in The Hive During Changes in Honey Supply
Authors: Oskin S V , Shishigin I N , Loza A A , Tsokur D S
Published: April 2022

Much research has been devoted to bee overwintering because it is the most dangerous period of the bee family’s life. The critical period for bees is the end of winter and the beginning of spring. During this time, there are large fluctuations in air temperature, and bees are forced to change their state from passive to active. By the end of winter, the club rises to the top of the hive, and the honey supply decreases significantly. Thus, this article considers a model that takes these changes into account. According to the results of the simulation, it was found that the movement of the bee club and the decrease of honey reserves in winter increase the fluctuations of the air temperature inside the hive. This affects the internal temperature regime of the bee club. At the same time, the stock of heat energy in the honey decreases and smoothes temperature fluctuations within the bee aggregation less. It is proposed to add a hive weight strain gauge to the previously developed electric bee heating control circuit, which will allow to correct the PWM output voltage coming to the heaters.
Effects of Manufacturing-induced Operating-conditions Amplified Stresses on Fatigue-life Prediction of Micro Gas Turbine Blades – A Simulation-based Study
Authors: Fameso Festus , Ramakokovhu Unarine , Desai Dawood , Salifu Smith
Published: April 2022

This study investigates the influence of residual stresses induced by the manufacturing process, on the fatigue life prediction of micro gas turbine blades manufactured by laser metal deposition additive manufacturing technique and heat-treated at different heat-treatment parameters. Finite element modelling, using commercial software Abaqus CAE ® and FE-Safe ®, was used to simulate the turbine blade and disk assembly’s operations and analyze induced stresses, as well as estimate the life cycle of the assembly. Results show internal stress build-ups, up to 400 MPa in magnitude can be induced in engineered components right from the point of additive manufacture, the effects of which can become amplified to as much as double that scale or more by the time the component is in operation. As much as between 75% to 300% fatigue life prediction error reduction can hence be attained by simply accounting for induced stress contribution of the process of its manufacture, rendering cost-saving condition-based monitoring and maintenance/overhaul decision making options.
Stimulation and Acquisition’ System to Obtain the Visual Evoked Potential Related to the Optic Nerve Pathologies
Authors: Montalvo Aguilar J A , Bazan Trujillo I , Ramírez-García A
Published: April 2022

The development and integration of an electroencephalographic signal acquisition and stimulation system is proposed to support the detection of pathologies related to the optic nerve. It is based on the extraction and analysis of a characteristic waveform called Visual Evoked Potential immersed in the electroencephalographic register. Some parameters of this potential, as latency and amplitude, are affected by the optic nerve pathologies, and measurement of changes from its normal states can be used as indicators of abnormal visual functionality of a patient. The proposed stimulation system can generate Visual Evoked Potential and multifocal Visual Evoked Potential which can help to locate pathologies in different areas of the visual field.
A Novel Progressive Response Surface Method for High-order polynomial Metamodel
Authors: Zheng Guanchao , Ariffin Mohd Khairol Anuar Bin Mohd , Ahmad Siti Azfanizam Binti , Aziz Nuraini Binti Abdul , Xu Wen
Published: April 2022

The response surface method (RSM) model as a general metamodel has already widely been applied to many practical problems. However, the majority of studies only focus on the 2nd-order terms RSM model instead of how to determine the high-order terms. This paper introduced a novel progressive response surface method (NPRSM) combining optimal Latin hypercube design (OLHD), moving least square method (MLSM) and statistical test. This NPRSM model can decide the high-order terms by progressive procedure. Then three numerical function can be proposed to validate the accuracy and the approximated performance of the NPRSM model.
Numerical Investigation of Charge Packet Dynamics in Polyethylene Assuming Barrier Height-Electric Field Hysteresis Hypothesis
Authors: Cai Shikai , Li Hongpeng , Sun Zhipeng
Published: April 2022

Charge packet phenomenon is a sign of the impending breakdown of the dielectric materials. In order to discuss the formation mechanism of charge packets, space charge characteriscs in polyethylene under the electric field of 150kV/mm are simulated based on the bipolar transport model assuming hysteresis in the barrier height for holes. It is found that if hysteresis in the barrier height is not introduced, net charge densities in the vicinity of the electrodes increase with the increase of polarization time. However, charge packets could not be reproduced without hysteresis hypothesis. When hysteresis loop in the barrier height are incorporated, charge packets are generated and propagated with the velocity about 3μm/s. The dying away of charge packets is not observed, which disagrees with the experimental data.
Study on Two Residual Flux Suppression Strategies of Current Transformer During Automatic Reclosing
Authors: Deng Chenglin , Deng Chuanhai , Wang Han , Zhong Jianying , Cai Xinjing
Published: April 2022

After power system short-circuit fault occurs, there is a large amount of residual magnetism in current transformer core, which will lead to wrong operation of connected relay protection and affect its reliability. Based on the direct current method, this paper puts forward two kinds of current transformer residual flux suppression strategies, which are constant voltage variable frequency (CVVF) and variable voltage constant frequency (VVCF), the magnetic flux of the core is gradually reduced by controlling the polarity of the output voltage of the switch module. The principle of residual flux suppression is introduced, and the method of parameter selection is given. The suppression effect of two residual flux suppression strategy is simulated and analyzed by experiment simulation. The results show that the two residual flux suppression strategies can demagnetize the current transformer core during automatic reclosing, but the constant voltage CVVF residual flux suppression strategy is simpler and more efficient.
Design and Implementation of a Mixed Reality Night Hoisting Assistance System Driven by Digital Twins
Authors: Li Hengwei , Wang Wei , Qu Jue , Qiu Ang , Niu Chenghong , Li Chengyu
Published: April 2022

Hoisting at night has low visibility and high operational complexity, which has the problems of large cognitive load and high risk. With the help of digital twin (DT) and mixed reality (MR), the article designs and implements a MR night hoisting assistance system driven by DT. The system is developed on the Unity3D platform and based on the UNet networking communication mechanism. It realizes the functions of fusion highlighting, motion synchronization, multi-terminal collaboration and error display. It also has multiple interaction methods such as voice interaction, gesture recognition, and sight tracking. The research results have positive significance for improving the effect of night hoisting.
Direction Relation Matrix Model Considering the Location Characteristics
Authors: Cheng Mianmian , Sun Qun , Kang Shilun , Chen Huanxin , Yang Na , Li Chunyan
Published: April 2022

To resolve the problem that the conventional direction relation matrix (DRM) models are not sensitive to the location characteristics of the target object, a DRM model that takes into account the location characteristics is proposed. Based on spatial cognition, the concept of taking the direction field of the target into consideration is provided, and a probability density function of the direction field is established. The cumulative probability of the region where the target object is located is used to replace the area in the conventional DRM model, and two methods are given for cumulative probability calculation. The cumulative probability is used to assign values to the direction relationship matrix. Experimental results show that, compared with the conventional DRM model, when the target is present in multiple regions, the method proposed in this paper leads to results that are more consistent with human intuitive experience and describes the direction accurately. When the target is only present in a certain fixed region, the proposed method has the same performance as the conventional DRM model. Therefore, the method proposed in this paper alleviates to a certain extent the problem that the conventional DRM models are not sensitive to location characteristics.
A Hybrid-ARQ Method with Adaptive Receiving Buffer Duration in Real Time Video Streaming
Authors: Cheng Baoping , Tao Xiaoming , Lei Peng , Zhou Junhua , Wang Duo , Chen Min
Published: April 2022

To decrease end-to-end delay for streaming media over internet, the transmission method based on best-effort model is always employed in Real Time Communication (RTC) system. However, the packet-loss, jitter and congestion occur frequently because the quality of transmission cannot be guaranteed, which causes lag and splash of video. Therefore, an optimized hybrid Automatic Repeat Query (ARQ) solution with adaptive receiving buffer duration is proposed to guarantee the quality of video transmission. In the method, the loss rate was used to adjust the buffer duration and calculate the redundancy for Forward Error Correction (FEC). The results show that the method in this paper gains lower end-to-end delay and better Mean Opinion Score (MOS) values while ensuring higher fluency in weak network scenarios.
Synthesis of NaA Zeolite from Blast Furnace Slag (BFS) and Its Utilization for Adsorption of Basic Dye (Methylene Blue)
Authors: Li C X , Zhang Q W , Li L
Published: April 2022

The adsorption process of methylene blue (MB) onto blast furnace slag (BFS) based zeolite (BFSZ) was discussed. Via the analyses of XRD, FE-SEM, XRF, CEC and SSA, the main composition in in the product was Na-A zeolite. And the Na2O content, CEC value and SSA value of the BFSZ samples was significantly increased to 19.61 wt.%, 3.06 meq/g and 27.55 m2.g1 respectively. Moreover, the adsorption kinetic for MB onto BFSZ was examined and best represented by Pseudo-second-order kinetic model. Moreover, the adsorption capacity of MB from aqueous solutions reaches up to 21.89 mg.g1 at 30 °C.
Over-the-Air Programming System for IoT Devices with a Non-native Wireless Update Service
Authors: Lozano Domínguez J.M. , Mateo Sanguino T.J. , Redondo González M. J. , Fernández de Viana González I.J.
Published: April 2022

In the last years, many solutions have been developed based on the Internet of Things (IoT) applied to several fields such as agriculture, road safety or electric lighting, among others. These devices are usually located in places that are not easy to access, which makes their software difficult to update. These updates should be carried out to improve the software of the devices to include new functionalities and/or solve security problems. This paper presents an Over-the-Air (OTA) programming system for devices that do not natively integrate a wireless update service. A description of the hardware used is included, as well as the update management application developed to carry out this task. The approach proposed has been validated by updating a microcontroller-based system applied to the area of road safety. The validation consisted in measuring the additional consumption required by the auxiliary update system compared to the base consumption, as well as determining the time required to update an IoT node in both wireless and wired mode. The results obtained show a reduction in consumption of 577% and a reduction in the updating time of 66%.
Extraction and Application of Inertial Sensors-Based Kinematic Parameters in a Clinical Walk Test among Stroke Survivors
Authors: Han S L , Cai M L , Sugiharto T , Pan M C
Published: April 2022

A new framework for adopting inertial sensors in a clinical test was proposed and tested in this study. A self-assembled-and-coded, inertial sensor-based wearable system was validated by comparing it with a commercialized optical tracking apparatus. Twenty-five post-stroke patients were enrolled in a clinical walk test while wearing this validated system to simultaneously assess the affected lower extremities’ functional walk competency through extracted kinematic parameters. Their average walking speeds were correlated with various gait parameters, such as the ranges of motion of the individual joints along the sagittal plane and the low back motion. The validation results proved this developed system is precise and accurate. The average walking speeds showed a modest correlation with the range of motion of the hip (r = 0.33) and a moderate and negative correlation with the motion along the coronal plane of the low back (r = -0.55). Thus, this framework supports a new method to adopt wearable devices for clinical application. It also broadens the application of the clinical walk test as an integral assessment tool for assessing functional walking competency and gait parameters, which is feasible for rehabilitation canters to monitor post-stroke patients.
Research on Server Green Computing in 5G Data Center
Authors: Li Rui , Qu Yan , Zuo Jun
Published: April 2022

The global 5G commercial era is approaching. The throughput and number of connections of 5G will be 100 times that of 4G. The processing power of massive data will determine the experience of users surfing the Internet. In order to cope with the geometric growth of network data, the computing power and storage capacity of 5G data centers need to be correspondingly improved. With the surge of servers, the energy consumption of the 5G data center has also been greatly improved. How to effectively improve the performance of the server and reduce the energy consumption has become an extremely urgent problem. This paper focuses on the management method of the data center server in the context of 5G network transformation, and proposes effective solutions in combination with the application scenarios of large-scale 5G data centers.
Design of Network Security Protection System for Internet of Vehicles under Electric Internet of Things Background
Authors: Wang Xueer , Jin Min
Published: April 2022

At present, China’s Internet of Vehicles (IoV) industry is booming and constantly promoting the society to the intelligent era. However, the development of network technology not only brings the opportunity of technology promotion for the IoV, but also brings new network security risks. Therefore, it is urgent to further strengthen the construction of the protection system for the IoV. Based on the original architecture of the IoV, this paper first analyses the security risks of the terminal layer, the network layer, the platform layer and the application layer under the background of the electric internet of things. According to the new security threats faced by the four layers of the IoV, the network security protection system is constructed, which strictly follows the overall information security protection strategy of the State Grid Corporation of China and the new requirements of “network security level protection 2.0”. Deepening the construction of the intelligent defence system of the IoV would be significant for the development of coordinated network security and the IoV, and would continuously improve the protection ability of the IoV.
An Energy-Balance Unequal Clustering Routing Protocol for Wireless Sensor Networks
Authors: Zhang Wen-mei
Published: April 2022

On the basis of traditional unequal clustering protocol for wireless sensor networks, an energy-balance unequal clustering routing protocol is proposed. In the clustering stage, the entire network is divided into clusters of different sizes based on the remaining energy and the distance from the sink node to the node. In the cluster establishment phase, each node calculates the cluster head selection time based on the relative remaining energy, the position, the average distance between the nodes in the cluster. The cluster head is selected by time series, and non-cluster head nodes are selected to join the cluster based on the distance between cluster heads and the remaining energy of the relay cluster head. In the route establishment phase, an optimal transmission path based on minimum spanning tree is built, based on the distance between cluster heads, the residual energy and the distance from node to the sink node. During data transmission, a single hop within a cluster is adopted, and a minimum spanning tree multi-hop method is used between clusters, and the data is finally transmitted to the sink node. The simulation shows that the routing protocol can effectively balance energy consumption and save energy, and the life cycle of the network is prolonged.
Design of an Automatic Palletizer
Authors: Mendoza-Calderón Karen Daritza , Jaimes Jordy Andres Maldonado , Maradey-Lazaro Jessica Gissella , Rincón-Quintero Arly Dario , Cardenas-Arias Carlos Gerardo
Published: April 2022

Industrial automation has become an area in full development and of great importance for all industrial sectors since it allows to improve the productivity of companies and the quality of their products. Currently, factories (i.e., small, or medium) must implement new technologies to increase its production and provide qualified products to enter with force in regional markets and nationals. This article shows the design and start up of an automatic palletizer which will have a manual mode in which each actuator in the system can be operated independently; and an automatic mode that will organize the input elements in the previously established way. For companies that produce in batches, is important to reduce storage spaces in warehouses, dispose of their products in an orderly and practical way for their subsequent dispatch. This last process must be effective and fast so as not to generate inconveniences in the delivery of orders to buyers. Our project is focused to the footwear sector, especially, how to seek greater development and performance of these companies where the packaging time of their products can be optimized so that it can be used in other tasks within the company. Also, the result of this investigation shows the engineering process carried out to obtain a prototype of a functional, automatic, productive, quality, and economic product that meets the customer’s requirements. Improvements that will do and future work are included too.
Development of Two Control Strategies for Tracking the Trajectory of An Unmanned Underwater Structure Inspection Vehicle
Authors: Riaño Yorley Dayana Caro , Prada Sebastián Roa
Published: April 2022

This paper presents the development of two dual-loop control strategies for an underwater Remotely Operated Vehicle, ROV. The first strategy consists of two PID controllers while the second one features a LQG controller in the inner loop, and a PID controller in the outer loop. The transient response of the two strategies is compared when an anti-windup gain is applied and when there is no anti-windup gain, and a way to tune this gain in the case of statespace controllers is proposed. For further comparison, the strategies are simulated for a variable set point, for the three variables to be controlled, x, z, yaw, so that both their tracking and the effect of coupling can be seen. In conclusion, the use of anti-windup gain is recommended for control systems that reach saturation, so that they can react quickly when they are in an operating zone, and the use of a random matrix for the calculation of this gain in state-space controllers is suggested.
Research on Arduino Control System Design of Tencent QQ Software
Authors: Shan Shirui , Lv Zhenwei , Li Wenwen , Zhang Song-zhi , Ye Linan
Published: April 2022

Tencent’s related products occupy the first place in the domestic social software market. This paper explores the Internet of things control method by using Tencent QQ (hereinafter referred to as QQ) application, with the purpose of realizing an IOT system controlled by social chat software. The research finds that: taking user QQ as the instruction sending end, cqhttp as the message transmission center, through the information processing program, instruction judgment program, DSL parsing engine, command transmission program and execution program, and finally through Arduino control electronic components to make relevant actions. A social software IOT control system with simple control mode, flexible design, fast expansion, fast response, good fault tolerance and high security is realized. The implementation of the system can be used as a reference for relevant fans to realize the IOT control system with various IM software.
Dual-loop Hovering Control for Unmanned Helicopter
Authors: Zhang Miao , Ma Jianwei
Published: April 2022

The recent development of unmanned aerial vehicle flight control creates a strong demand for higher control accuracy and control quality. In this paper, the precise control and stable hovering problem are studied for unmanned helicopters. To solve the problem, we propose a hovering controller for dual-loop of unmanned helicopters. Firstly, the nonlinear mathematical model of unmanned helicopters is established based on Newton-Euler’s laws. Then, we respectively design the position model and attitude model. In the position model, we use the cascade PD controller to realize the precise control; In the attitude model, we use the cascade PD controller to realize the stable hovering. Simulation results show the effectiveness of the conclusions made in this paper.
Modeling and Control of One-stage Inverted Pendulum Body Based on Matlab
Authors: Lin Xueyan , Liu Xiaohua
Published: April 2022

In this paper, two mathematical models of the primary inverted pendulum are established based on the Simulink and the Simscape toolboxes of the MATLAB respectively. The inverted pendulum changes from the unstable state to the stable state after performing the state feedback control and the PID control method. Under these two control methods, the overshoot of the Simulink model is 57% and 80% smaller, and the adjustment time is 25% and 20% larger than that of the Simscape model. The control effect of the PID method in the two models is better than that of the state feedback method. The adjustment time of the pendulum rod is 40% and 37.5% smaller, and the overshoot is 82% and 61% smaller than that of state feedback control, respectively.
Reinforcement Q-Learning Based Current Control for Grid-Connected Three-Phase Inverters with Unknown System Dynamics
Authors: Wang Yeteng , Peng Yunjian
Published: April 2022

This paper proposes a Q-learning-based state feedback suboptimal controller to solve the current control problem of three-phase grid-connected LCL coupled inverters with unknown circuit parameters. In practice, the circuit parameters of the inverters will change obviously for reasons such as calculation errors, external environment and operation aging, which makes the dynamics of the inverter system become unknown. With the circuit’s model of the LCL inverters and the reference current dynamic, an augmented system is constructed and a discounted performance function is formulated as the optimal objective of current control which transform it into a H∞ tracking control. Using Q-learning algorithm with model-free characteristics, a current controller is proposed in which an iterative reinforcement learning (RL) algorithm is embedded. Simulations are presented to verify the valid of the proposed control scheme, where especially the results shows that it can keep excellent control performance under the condition of inverter parameter mutation and grid voltage distortion.
Research on Visual Servo Control of UAV Pod Based on Improved PID Algorithm
Authors: Zhao Mingyang , Yan Jie , Shi Dianxi , Wang Yanzhen , Pan Jianhen , Du Jing
Published: April 2022

In view of the traditional PID controller used in the UAV visual servo control, there are problems that the parameter setting is extremely troublesome, and the speed and stability of the system cannot be considered at the same time. An improved PID-based UAV pod visual servo control method is designed. By introducing the concept of integral separation, according to the size of the deviation between the target’s pixel coordinates in the image and the set expected pixel coordinates, it is decided whether the integral control is used or not, which can avoid large overshoot and improve control accuracy. The simulation experiment shows that the visual servo control algorithm based on improved PID has smaller tracking error and higher critical tracking speed than the visual servo control algorithm based on traditional PID, and it has better performance.
An Improved Model-Free Predictive Current Control Scheme for Open-Winding PMSM with Common DC Bus
Authors: Li Yongshen , Zhang Chengning , Li Xueping , Zhou Ying , Zhang Shuo
Published: April 2022

To improve the parameter robustness of the open-winding permanent magnet synchronous motor (OW-PMSM), this paper proposes an improved model-free predictive current control (MFPCC) method. First, the first-order ultra-local model of OW-PMSM is established, which does not contain any motor parameter. Secondly, a sliding mode observer (SMO) is introduced into the model to estimate the current in d-q-0 axis. Then, to suppress the torque ripple generated by the zero-sequence current (ZSC), the central hexagonal modulation strategy and the q-axis current injection method are combined, and the compensation current that needs to be injected into the q-axis is calculated according to the estimated value of ZSC. Finally, after considering the one-step delay, the voltage reference at the next instant is calculated based on the estimated values of d-q axis current and compensation current. Simulation and experimental results indicate that the proposed method can improve the parameter robustness of OW-PMSM, and the performance of current and torque has been improved under various parameter mismatch conditions.
Polynomial Wiener LQG Controllers based on Toeplitz Matrices
Authors: Moir T. J.
Published: April 2022

This paper re-examines the discrete-time Linear Quadratic Gaussian (LQG) regulator problem. The normal approach to this problem is to use a Kalman filter state estimator and Kalman control state feedback. Though quite successful, an alternative approach in the frequency domain was employed later. That method used z-transfer functions or polynomials in the z-domain. The transfer function approach is similar to the method used in Wiener filtering and requires the use of Diophantine equations (sometimes bilateral) to find the optimal controller. The contribution here uses a similar approach but uses lower triangular Toeplitz matrices instead of polynomials to gain advantage of eliminating the use of Diophantine equations. This is because the single Diophantine equation approach fails when the system has non-relative prime polynomials and the need for bilateral Diophantine equations is computationally far more complex.
Smart Dome 4.0: Low-Cost, Independent, Automated Energy System for Agricultural Purposes enabled by Machine Learning
Authors: Budiman Arief S , Gunawan Fergyanto , Djuana Endang , Pardamean Bens , Romeli Sugiarto , Putri Dianing NN , Aji Daisman PB , Rahardjo Kuat , Stevanus  , Ilham Wibowo M. , Daffa Nadiev , Owen Raymond
Published: April 2022

Many economically essential crops in Indonesia (such as coffee, tea, chocolate, or copra) require storage or drying under certain environmental conditions, especially temperature and humidity. The solar dryer dome, typically used for agricultural purposes in Indonesia, produces a sufficient amount of heat to increase the evaporation rate inside the dome and reduce the moisture content of the commodity. A hybrid solar dryer accompanied by a photovoltaic panel, fan, and ventilation system is generally suitable. The system can provide an optimum environment with minimum control. However, as the outdoor temperature and humidity change dramatically, such as at night time, more control is required. Based on Industry 4.0 technologies, we have developed a new kind of hybrid solar dryer that provides an optimum environment 24/7. The system, called Smart Dome 4.0, is an intelligent, low-cost, self-sufficient drying and storage system to support Indonesia Agriculture 4.0. The system has a local power generation unit to self-sustain the required energy and operate without connecting to the electricity grid. The system utilizes a machine-learning algorithm to predict the environmental condition and optimally uses self-generated electric power. The developed Smart Dome 4.0 technology is critical to producing a sustainable solar dome under drastic environmental dynamics.
Design of Low Parasitic Inductance SiC MOSFETs Halfbridge Power Modules
Authors: Wang Yifan , Gong Jinlong , Song Qihua , luo Li , Zhang Bin , Guo Qing
Published: April 2022

The working mechanism of a half-bridge SiC MOSFETs two chips parallel module is studied. Its parasitic inductance of the power module is simulated by using the Ansoft Q3D Extractor software, and its heat transfer mechanism is simulated using the finite element software ANSYS software. Aiming at reducing the parasitic inductance, a new topology of power chips inside the module is designed, which places the chips that are in the same working circuit loop in close vicinity to reduce the whole circuit length and area. Meanwhile, the thermal characteristics are also analyzed. Considering the factors of parasitic inductance and heat dissipation, the optimal module design scheme is finally determined.
Optimization of Bed Demand for Elderly Care Services Based on Leslie Matrix
Authors: Yu Jiawei , Yang Jun
Published: April 2022

With the deepening of the aging process and the weakening of the family’s ability to care for the aged, urban residents will have an increasing demand for elderly care service institutions in the future. Therefore, it is necessary to optimize the prediction of the demand for elderly service beds. In the paper, an optimization method of Leslie matrix is proposed to predict the future trend of the total population and aging by comprehensively considering factors such as birth rate and mortality rate, and analyze and predict the demand scale of elderly service beds according to the distribution of urban and rural areas and economic divisions. Based on the AHP model, the business opportunities for elderly service beds will be transformed into a quantitative evaluation model to analyzing the return rate of pension service investment in different regions. The simulation experiment shows that increasing the total number of elderly care institutions and improving them can effectively solve the insufficient number of elderly service beds.
An Optimization Method for Clearance Value of Electric Submersible Screw Pump
Authors: Fang Wang , Fei Cao , Chunqing Lin , Yaming Li , Wei Xie , Yun Li , Mengshi Yang , Jing Wang , Jingwen Zhao
Published: April 2022

Electric submersible screw pump often works at high speed, which has the characteristics of high speed, high temperature and large rubber deformation. In case of sudden shutdown, the rubber will not shrink at high temperature, which may lead to serious accidents such as pump locking and electrode burning. In the initial stage of pump start-up and restart after pump shutdown, due to the above reasons, it is often difficult to start the pump, which makes the pump unable to work normally. Therefore, this paper studies the clearance value of the electric submersible screw pump, calculates and tests the interference amount and initial interference amount, improves and optimizes the clearance value of the electric submersible screw pump, effectively improves the working efficiency and service life of the electric submersible screw pump, achieves the purpose of improving the quality and efficiency of oilfield production, and has a very important practical significance for the development of the rodless pump market.
X-Ray Pulsar-based Navigation Scheme for Solar System Boundary Exploration
Authors: Wang Y S , Wang Y D , Zheng W , Song M Z
Published: April 2022

For solar system boundary exploration mission, this paper designed an X-ray pulsar-based navigation (XNAV) scheme. The Fisher information matrix is used to choose optimal pulsar observation configuration. Based on the selected pulsar configuration, the accuracy of pulsar navigation and stellar angle navigation is compared. Besides, the navigation performance of XNAV is verified by the orbits of voyager 1, voyager 2 and pioneer 10 respectively. Simulation results show that the pulsar navigation could provide accurate positioning results for solar system boundary explorers.
A Flexible Ethernet Calendar Allocation Based on Client Traffic
Authors: Dai Yong , Wu Xilao , Zhao Jincheng , Song Jiang , Cong Lin , Li Zhicheng , Wang Ying
Published: April 2022

Aiming at the problem of low link bandwidth utilization in the current FlexE client slot allocation mechanism, a FlexE calendar bandwidth allocation mechanism that is compatible with the client data transmission rate is proposed, and the LSTM algorithm is used to predict network traffic data, and according to the client priority and traffic prediction results, the client is allocated with slots. Experiments show that, compared with the traditional FlexE slot allocation mechanism, the method proposed in this paper can make the bandwidth resource utilization rate reach 82.8%.
Transport properties of graphene in proximity with alkali metals
Authors: Peralta M , Vaca-Chanatasig C , Vera-Nieto R , Verrilli D
Published: April 2022

In this work, we propose the analysis of the electronic and transport properties of graphene decorated with Lithium and Potassium adatoms. We will study two inequivalent metal adsorption sites: the Top site, on top of a carbon atom of one sub-lattice of graphene; and the Hollow site, in the middle of a C6-unit. With this end, we will use an analytical Tight Binding Model, for graphene with adsorbate atoms of lithium and potassium, for the two different adsorption positions. Then, we use the Green’s function equation of motion method to calculate the corresponding band structures and density of states, and numerical calculations for the conductance are performed with the quantum transport simulation package of python (Kwant). We find that the bands are down shifted with respect to pristine graphene, indicating a doping with electrons. For the Top case, the AB symmetry breaking produced in this configuration, generates small bandgaps of approximately 170 meV for potassium and 220 meV for lithium. Finally, the conductance is shifted in energy in the same way as the bands, preserving its growing rate with the absolute value of the energy as for pristine graphene.
Photocatalytic activity of Fe/Ti-based compounds obtained from ferro-titaniferous mineral sands via a simple soft chemistry route
Authors: Galeas Salomé , Valdivieso-Ramírez Carla S. , Pontón Patricia I. , Goetz Vincent , Guerrero Victor H.
Published: April 2022

Fe/Ti-based compounds were synthesized from ferro-titaniferous mineral sands using aqueous oxalic acid under subcritical water (sCW) conditions (135°C/50 bar/4 h) and their photocatalytic activity was evaluated against methylene blue or caffeine under UV-A and visible radiation. The X-ray diffraction and Raman spectroscopy analyses revealed that the as-synthetized compounds were mainly comprised of ferrous oxalate, followed by titanium dioxide. This proved the complete transformation of the mineral precursor within 4 h using oxalic acid/sCW as the reaction medium. The photocatalytic studies showed that methylene blue and caffeine were photodegraded under UV-A and visible radiation by the as-synthesized Fe/Ti-based compounds. Methylene blue removal was up to 92.8 and 97.4% after 6 hours under UV-A or visible irradiation, respectively. Caffeine removal, however, reached 69.3 and 59.6% after 16 h of exposure to UV-A and visible light, respectively. The as-synthesized compounds can be potentially used as a ferrous-based catalyst in heterogeneous photocatalysis for decontamination of water systems from organic pollutants.
Research on risk prediction method of software robot based on artificial intelligence
Authors: Kang Zelun
Published: April 2022

Aiming at the problem of software robot’s recognition of life scenes, this paper studies the recognition and judgment method based on AI edge computing. Based on artificial intelligence methods and the theory of edge computing, through the analysis of the overall architecture of edge computing, the scene judgment rules and recognition algorithms are clarified. Mainly, the feature extraction and recognition part of the software robot image recognition function is arranged in the edge server, so that the judgment and recognition can be quickly realized and the system operation efficiency can be improved. The experimental verification shows that: under the same conditions, the software robot identification error of the method in this paper is lower, and the calculation time is shorter than that of other software robots, which is far superior to the traditional identification method. At the same time, by changing the comparison of data receiving methods, it can also be proved that the use of edge computing is more efficient, and the recognition problems in the work of software robots can be realized.
Biocompatible Hydrogel Modified Silicon Nanowire Field Transistor for Highly Sensitive pH Detection
Authors: Li Gangrong , Wei Qianhui , Zhang Qingzhu , Wei Feng
Published: April 2022

In this work, a silicon nanowire field-effect transistor (SiNW FET) device was developed and applied to pH sensing. A hydrogel was synthesized by radical polymerization as the dielectric and functional layer of SiNW FET. The spin coating process of the hydrogel was defined through different rotating speed. The results revealed that the suitable glue mixing process was determined to be 500 rpm/min at low speed and 4500 rpm/min at high speed. We demonstrated the effect of pH solutions on the sensitivity of the SiNW FET sensor modified by hydrogel. The SiNW FET sensor was used to detect a solution pH ranging from 5 to 11, with the response current increasing stepwise as the pH value increased. Compared with SiNW FET, the hydrogel-coated SiNW FET had higher sensitivity and time response rate for pH sensing. The obtained results demonstrated that modification of hydrogels can significantly increase the pH sensing properties of SiNW FET.
Analysis of the phase transition of patch colloidal particles and the molecular dynamics simulation
Authors: Zhou Haolei
Published: April 2022

Anisotropic particle system means that the interaction between particles in the system depends not only on their spatial coordinates, but also on the orientation of each particle due to the influence of many factors such as structure, shape, electronic properties and environment. The introduction of orientation coordinates makes the phase space describing this kind of system have higher degrees of freedom and more complex symmetry. Therefore, the study of its general properties has more basic significance in physics. Patch colloidal particles, which have become one of the research hotspots in the field of soft matter physics in recent years, are a typical mesoscopic physical system with anisotropic interaction. In this paper, the two-dimensional patch colloidal particle system is studied as follows: (1) the phase structure of the system is preliminarily studied and analysed. It is found that the phase behaviour of the system at high temperature is similar to that of isotropic Lennard - Jones system is similar. Under low temperature, the system with low patch coverage has strip structure in the condensed phase and complex self-assembly structure in the gas phase; (2) It is found that the long-term diffusion belongs to isotropic normal diffusion, while the short-term diffusion is anisotropic ballistic diffusion, and the particle motion direction is always perpendicular to the patch orientation; (3) The melting behavior of the system is studied. It is found that the melting is a two-step phase transition, which is the same as that of the two-dimensional isotropic colloidal system;
Composition control and selective infrared radiative properties of copper alloy oxides by DC reactive sputtering
Authors: Li Yongqing , Wang Qun
Published: April 2022

In order to identify new selective infrared radiative materials, Cu80Ni15Ag5 and Cu70Ni25Ag5 oxides were prepared by DC reactive magnetron sputtering under atmosphere with different ratio of argon to oxygen. The composition of the copper alloy oxides was analyzed by XRD, XPS and Raman. When the ratio of argon to oxygen was 50:2, the alloy oxide is amorphous, whereas the alloy oxide prepared at the ratio of argon to oxygen from 50:4 to 50:10 is Cu4O3. The doping of Ni and Ag may impede CuO phase formation, deteriorate the crystallinity, and increase the defects. The emissivity measurement results show that Cu70Ni25Ag5 oxides prepared at the ratio of argon to oxygen of 50:10 have good selective infrared radiative properties, and the emissivity difference is more than 0.8 between 3μm band and 8-14μm band.
Binary system modelling: The determination of stellar physical quantities in a double-lined spectroscopic system
Authors: Qi Wenzhao
Published: April 2022

The mass and size of a star are essential characteristics in astronomical measurement. This paper presents the investigation of two components of a binary system through the analysis of the BH Virginis system. The stellar masses and size can also be obtained by establishing a best-fit binary model with actual data and determining the corresponding stellar parameters using the Nightfall program. The results obtained for the primary star include mass (1.095±0.060 M⊙), mean radius (1.156±0.084 R⊙) and luminosity (1.462±0.11 L⊙). For secondary stars, the results obtained are mass (1.205±0.060 M⊙), mean radius (0.867±0.072 R⊙) and luminosity (0.940±0.08 L⊙). It demonstrates the basic properties of the binary system and gives a general idea of obtaining a relatively precise result based on an eclipsing spectroscopic method.
Impact of Hot-Carrier Degradation Due to Moisture Diffusion Based on 0.153um CMOS
Authors: Lin Zhengyu , Wang Dejin , Yang Fei , Zhou Yaohui , Sun Xiaofeng , Wen Haoyu
Published: April 2022

The study aims to investigate enhanced hot-carrier-induced degradation of MOSFETs due to moisture diffusion from inter-metal oxides. By studying different split of back-end in details, it is confirmed the impact of hot-carrier-induced degradation due to moisture diffusion under different conditions. Analyzing how much current drops after 10K times of programming and erasing verifies the cause of device degradation. Experimental results indicate that HDP thickness reduction, alloy after HDP, deposition of SRO layer before HDP and material of TEOS can efficiently enhance hot-carrier-induced degradation. According to the experimental results, the influence of moisture diffusion has been clarified, providing directions for enhancing the hot-carrier-induced degradation of MOSFETs, and providing relevant experience for subsequent product development.
Hybrid RANS/LES/DNS of turbulence flow along a flat plate
Authors: Zhang Jiayan , Cai Runhua , Shi Lidan
Published: April 2022

Contemporarily, direct numerical simulation (DNS), Large-eddy simulation (LES), and Reynolds-averaged Navier-Stokes (RANS) are the three most mature Computational fluid dynamics (CFD) used methods for turbulence simulations. The calculation accuracy and difficulty of these three models are decreased in order. For the sale of finding a balance between the accuracy of the results and the efficiency, we tried to combine these three models. In this paper, for an adiabatic and incompressible flow, we use DNS, LES, and RANS at first. After analyzing their results, a time-space relationship is obtained. First, for a fixed time point, the flow field is divided into three parts by the distance from the wall. Secondly, a long-term simulation is performed to obtain a general partition, and ensure that the models used in each zone are both efficient and economical. We use DNS results as the standard, with an error within 5% as the partition basis. According to the results, the calculation accuracy after hybridization reaches 99% of using DNS alone. Besides, the amount of calculation required is only 59% of using DNS alone, which is smaller than DNS. On this basis, we can achieve our goal based on the hybrid method. Meanwhile, it is also aware that our method is still needed to be improved, where we will gradually make this method in future work. These results shed light on a new hybrid method.
The interface trap analysis of AlGaN/GaN high electron mobility transistors with temperature based on conductance method
Authors: Liang Yongfeng , Zhang Heqiu , Chen Huanhuan , Xing He , Cai Tao , Ye Yufan , Liang Hongwei , Xia Xiaochuan , Guo Wengping , Xu Nanfa , Xi Qingnan , Liang Xiaohua , Huang Huishi
Published: April 2022

In this paper, the characteristics of AlGaN/GaN high electron mobility transistors were tested and analyzed at high temperature. The experimental temperature range was 25~500°C. Frequency-dependent capacitance and conductance were adopted to investigate high temperature characteristics of interface trap. Results show that there is a kind of trap at the device interface. The trap density and time constant are (8.41×1010~1.40×1011)eV-1cm2/(0.398~0.636)μS and (1..03×1011~1.15×1011)eV-1cm2/(0.455~0.532)μS at different voltages and temperatures. With the increase of temperature, the trap density and time constant increase. High density interface traps are one of the reasons why device characteristics deteriorate with increasing temperature.
Study QGP through the Correlation Function with Pb-Pb Collisions at

SNN=2.76TeV
Authors: Lin Jie-ming , Chen Yi-jie , Li Jun-hao , Liu Xiao-chen , Liu Zi-han
Published: April 2022

This paper focuses on repeating and verifying the predecessor’s work. We briefly describe our dataset from CMS and then provide information about the Glauber Model built with python. Then, the correlation function of our data and different orders of its Fourier decomposition are presented to verify the former discussion. With the correlation function, we will show the fluctuation of the directed and elliptic flow caused by the non-flow, which comes from the intractable strong interaction during the evolution of the QGP. Based on the assumption that the non-flow contribution is ignorable in large relative pseudorapidity interval, (|Δη|), we separate the non-flow contribution from the elliptic flow. Finally, we provide a detailed derivation of the Fourier decomposition of correlation and discuss their physical meaning, absent in general paperwork.