bluuebunny/crossref_metadata_2025 huggingface dataset:
Geometric progress in the thickness of exfoliated van der Waals crystals on the example of MoS2
Authors: Tamulewicz-Szwajkowska Magdalena , Zelewski Szymon J. , Serafińczuk Jarosław , Kudrawiec Robert
Published: February 2022

To obtain molecularly thin flakes via mechanical exfoliation from a bulk layered crystal, the process should be repeated multiple times, but the mathematical principle behind this phenomenon remains unknown. In this paper, we show how the thickness of the MoS2 flake changes with subsequent cleavages of the adhesive tape, with the tests carried out on two widely used dicing tapes and Scotch removable tape. In the beginning, we assumed that with each subsequent tear of the tape, the thickness of the material decreases by half. We discovered that the exfoliated crystal thickness decreases with geometric progress and proposed a formula depicting that phenomenon. In addition, the exfoliated flakes are observed to crumble during the process and the fragmentation factor is discussed as well. Our observations will allow for more efficient estimation of the number of steps required to produce a sample of the desired thickness, relevant for tuning electronic transport properties and optical activity of two-dimensional materials.
Cow–calf efficiency of beef cows grazing different herbage allowances of rangelands: hepatic mechanisms related to energy efficiency
Authors: Casal Alberto , Garcia-Roche Mercedes , Cassina Adriana , Soca Pablo , Carriquiry Mariana
Published: February 2022

Context Improvement in efficiency of energy utilisation of cow–calf systems could benefit beef production profitability and sustainability. Energy efficiency has been associated with mitochondrial function; therefore, hepatic mitochondrial function and oxidative stress could play a key role in energy efficiency of beef cows. Aim We evaluated the effect of two herbage allowances from rangelands (Campos biome) on cow–calf energy efficiency, hepatic mitochondrial density and function, and oxidative stress of purebred (Hereford and Aberdeen Angus) and reciprocal F1 crossbred beef cows. Methods Mature cows (n = 32) were used in a complete randomised block design with a factorial arrangement of herbage allowance (2.5 vs 4 kg dry matter/day; low vs high) and cow genotype (pure vs crossbred) over 3 years. At the end of the third year, cows were slaughtered at 190 ± 10 days postpartum. Liver was dissected and weighed, and samples were collected and snap-frozen pending analysis of mitochondrial density and oxidative stress markers. Estimated cow–calf energy efficiency was calculated by using total cow estimated metabolisable energy intake as input and calf energy retained at weaning as output. Key results Cow–calf energy efficiency was greater (P ≤ 0.07) for high than low herbage allowance and for crossbred than purebred cows. Mitochondrial density biomarkers (hepatic citrate synthase enzyme activity, citrate synthase mRNA, and mitochondrial:nuclear DNA ratio) were greater (P ≤ 0.03) for high than low herbage allowance. Plasma pro-oxidants and plasma antioxidant capacity were greater (P ≤ 0.07) for crossbred than purebred cows. Plasma oxidative stress index and expression of hepatic 4-hydroxynonenal protein adducts were affected (P ≤ 0.06) by herbage allowance × cow genotype interaction. Conclusion Greater cow–calf energy efficiency was associated with greater hepatic mitochondrial density without differences in mitochondrial function. Contrary to expectation, greater efficiency of crossbred than purebred cows was associated with increased hepatic oxidative damage, which probably reflects greater liver metabolic activity in crossbreds. Implications Herbage allowance and cow genotype affect cow–calf efficiency, hepatic mitochondrial function and oxidative stress markers. Greater efficiency of crossbred cows seems associated with increased hepatic oxidative damage.
Changes in leaf ecophysiological traits and proteome profile provide new insights into variability of salt response in the succulent halophyte
Authors: Belghith Ikram , Senkler Jennifer , Abdelly Chedly , Braun Hans-Peter , Debez Ahmed
Published: February 2022

Natural variability of stress tolerance in halophytic plants is of significance both ecologically and in view of identifying molecular traits for salt tolerance in plants. Using ecophysiological and proteomic analyses, we address these phenomena in two Tunisian accessions of the oilseed halophyte, Cakile maritima Scop., thriving on arid and semi-arid Mediterranean bioclimatic stages (Djerba and Raoued, respectively), with a special emphasis on the leaves. Changes in biomass, photosynthetic gas exchange and pigment concentrations in C. maritima plants treated with three salinity levels (0, 100 and 300 mM NaCl) were monitored for 1 month. Comparative two-dimensional gel electrophoresis (2-DE) revealed 94 and 56 proteins of differential abundance in Raoued and Djerba accessions, respectively. These salinity-responsive proteins were mainly related to photosynthesis and oxidative phosphorylation (OXPHOS). Although Djerba accession showed a lower biomass productivity, it showed a slightly higher CO2 assimilation rate than Raoued accession when salt-treated. Photosynthesis impairment in both accessions under salinity was also suggested by the lower abundance of proteins involved in Calvin cycle and electron transfer. A significant increase of protein spots involved in the OXPHOS system was found in Djerba accession, suggesting an increase in mitochondrial respiration for increased ATP production under saline conditions, whereas a lesser pronounced trend was observed for Raoued accession. The latter showed in addition higher abundance of proteins involved in photorespiration. Salt-challenged plants of Djerba also likely developed mechanisms for scavenging ROS in leaves as shown by the increase in superoxide dismutase and thioredoxin, while an opposite trend was found in Raoued.
Nonlinear analysis of the internal resonance response of an L-shaped beam structure considering quadratic and cubic nonlinearity
Authors: Nie Xiaochun , Gao Xin , Wang Lingzhi , Tan Ting , Yan Zhitao , Yan Zhimiao , Liu Xinpeng
Published: February 2022

The nonlinear behaviors of the L-shaped beam structure based on 1:2 internal resonance are investigated. The governing equations considering quadratic and cubic nonlinearity of the L-shaped beam structure are verified by the transient dynamic analysis of the finite element model. The approximate analytical solution for this system is derived by the method of multiple scales, and verified by the numerical solution. The Jacobian matrix of the modulation equation is employed to determine the equilibrium stability of the vibration response. The effects of the excitation frequency, amplitude and cubic nonlinear terms on the nonlinear responses of the primary resonance of the first and second modes are discussed. The bifurcation diagram, spectrum, phase plane and Poincaré section are applied to investigate the nonlinear vibration response. The results reveal that many nonlinear phenomena are observed, such as double-jump, hysteresis, Hopf bifurcation, modal saturation, multiple solutions, multi-softening and so on. The influence of cubic nonlinear term on internal resonance response should be considered. The broadband characteristics of internal resonance system are broadened by the nonlinear softening and hardening in the frequency response curve. In the primary resonance of the second mode, the hardening region in the frequency response curve becomes the softening region with the increase of excitation amplitude. The double-jump phenomenon is found in this newly formed softening region, and up to five solutions are observed in this region, including three sink points and two saddle-nodes. The broadband characteristics of the system is of great benefit to the application of broadband piezoelectric vibration energy harvesting.
Thermodynamics of an Ising-like XXZ chain in a longitudinal magnetic field in the framework of the quantum transfer matrix approach
Authors: Bibikov P N
Published: February 2022

Taking the Ising chain as a reference model we have derived a perturbative expression for the free energy density of the Heisenberg–Ising chain with strong easy-axis anisotropy. All calculations are performed on the ground of the quantum transfer matrix approach. The obtained result agrees with the direct high-temperature expansion. It also agrees with the low-temperature cluster expansion in the special subregime when quantum fluctuations are weak against thermodynamical ones.
Extracting stochastic dynamical systems with α-stable Lévy noise from data
Authors: Li Yang , Lu Yubin , Xu Shengyuan , Duan Jinqiao
Published: February 2022

With the rapid increase of valuable observational, experimental and simulated data for complex systems, much efforts have been devoted to identifying governing laws underlying the evolution of these systems. Despite the wide applications of non-Gaussian fluctuations in numerous physical phenomena, the data-driven approaches to extract stochastic dynamical systems with (non-Gaussian) Lévy noise are relatively few so far. In this work, we propose a data-driven method to extract stochastic dynamical systems with α-stable Lévy noise from sample path data based on the properties of α-stable distributions. More specifically, we first estimate the Lévy jump measure and noise intensity via computing mean and variance of the amplitude of the increment of the sample paths. Then we approximate the drift coefficient by combining nonlocal Kramers–Moyal formulas with normalizing flows. Numerical experiments on one- and two-dimensional prototypical examples including simulated and real world measurement data illustrate the accuracy and effectiveness of our method. This approach will become an effective scientific tool in discovering stochastic governing laws of complex phenomena and understanding dynamical behaviors under non-Gaussian fluctuations.
Research on cooperative control strategy of multi-motor system based on fuzzy inference
Authors: Hu Tianqi , Tan Yuegang , Li Ruiya
Published: February 2022

General distributed multi-motor control system has a low synchronization performance and a poor coordination control accuracy. In order to improve the deficiencies, the fuzzy control method is used. Firstly, the fuzzy PID controller is designed to improve the control accuracy of a single motor in the control system; Then, aiming at the shortcomings of the traditional deviation coupling structure, an adjacent deviation coupling control strategy based on fuzzy inference and a speed compensator are designed to improve the synchronization performance of the whole control system. The simulation results show that the tracking error of single motor and the synchronization error between motors are greatly reduced.
A Dual-band Bandpass Filter with The Second Passband Independently Tunable
Authors: Yang Hong , Zhang Dewei , Zhang Yi , Bian Chenge , Sun Guanghui
Published: February 2022

This article proposes a dual-band bandpass filter (BPF) based on stub-loaded resonator (SLR) with the second passband independently tunable. Varactors loaded on the end of the central stub are employed to independently tune the second passband. Two shunt quarter-wavelength open stubs and source-load (S-L) coupling are applied to generate transmission zeros (TZs) to enhance the selectivity and improve the out-band rejection. For verification, a tunable dual-band BPF is designed, fabricated and tested, which realizes frequency tuning range (FTR) of the second passband from 2.24 to 2.71 GHz with constant fractional bandwidth (CFBW) of 1.5±0.4%. The simulated and measured results are in good accordance.
A low-noise and fast transient response LDO design for high-speed SerDes
Authors: Song Shengyu , Chen Jianjun , Yuan Hengzhou , Xing Haiyuan , Wen Yi
Published: February 2022

In order to deal with the special needs of high-speed digital-analog hybrid circuits for power supplies, this article has designed a LDO circuit specifically applied to high-speed SerDes. In the design process, a cross-coupled charge pump was used to increase the swing and reduce power supply noise, and to increase the gain and reduce the area overhead, the design of an asymmetric operational amplifier was introduced. At the same time, the use of the cascode structure is also conducive to the frequency stability of the loop and provides sufficient phase margin for the circuit. Through simulation verification, the low-frequency maximum internal noise of this LDO is only 0.96uV/sqrt(Hz), the transient response time when the load changes from low to high is 38ns, the transient response time from high to low is 84ns, the phase margin is 87.3deg, and the PSRR is 56.8dB.
Comparison between the Ultra-wide Band based indoor positioning technology and other technologies
Authors: Wu Pengtao
Published: February 2022

In recent decades, there have been many applications of positioning and navigation systems, the most representative of which is GPS (Global Positioning System). This technique is very accurate for outdoor navigation, but it cannot provide reliable positioning data indoors. This paper firstly compares the different indoor positioning technologies and analyses their bottleneck. Then the suitable algorithm of UWB based on indoor positioning technology (IPT) is discussed including Angle of arrival (AoA), Time of arrival (ToA), Time difference of arrival (TDoA), and Received Signal Strength (RSS). Eventually, the paper finds that although UWB-based indoor positioning technology still has many problems such as high deployment equipment costs to be solved, it is suitable for widespread applications due to its special advantages such as strong resistance to multipath effects.
Intelligent decision-making system for realizing the automatic control of Yangzhuang sluice based on the internet of things technology
Authors: Zhou Wei , Chen Sen , Zou WenHai , Yang Jing , Wu Meng
Published: February 2022

Yangzhuang sluice is located on the Gaoyou Lake control line of the Huaihe River into the Yangtze river and was built in May 1970. Due to the inherent insufficient design and historical reasons, Management Office has been using manual operation scheduling management of the sluice gate. The safety risks are large and the scheduling accuracy is not high. In order to further improve the comprehensive scheduling performance of sluice andenhance the scientific level of scheduling management, establish automatic control system, automatic control to realize power distribution system and gate, meet the requirements of “unattended, less people on duty”, and build sluice management system based on the Internet of Things system, realize the automatic monitoring and management of sluice, which is also the development demand of modern water conservancy.
A design of high-Speed SMS4 cipher circuit
Authors: Wu Chenjie , Tang Ying , Wei Yi
Published: February 2022

SMS4 cipher algorithm is a commercial cipher independently developed by china. This paper proposes a circuit design of high-speed SMS4 cipher algorithm, which adopts two-dimensional expansion and key path optimization technology. The round key generation module runs synchronously with the encryption module, and the running round is constant, which can effectively resist the side channel attack. Using Xilinx artix-7 for synthesis, the results show that the design function is correct, and achieves the balance of computing speed and resource occupation.
Secure transmission strategy of multi UAV relays in jamming environment
Authors: Yang Lei , Gao Song , Liu ZiYue , He ZhuoJun
Published: February 2022

This paper studies a multi UAV relays communication system based on secure transmission strategy in jamming environment. In the multi UAV relays communication system with interference, we use the physical layer security technology based on the physical layer to maximize the minimum average rate by optimizing the flight trajectory and resource allocation of the signal source and UAV relays, and adjust the channel state information of the legal communication channel, so as to improve the communication performance of the legal channel. Since the optimization problem and constraints are nonconvex and cannot be solved directly, we decompose it into two sub optimization problems: interference optimization and strategy optimization, which are solved respectively. Finally, the joint optimal solution of the original optimization problem is obtained by alternating iterative optimization, the simulation results show that by jointly optimizing the transmission power and flight trajectory of signal source and UAV relays, the influence of interference source on wireless communication is reduced and safer communication is realized.
Balance Control of an Inverted Pendulum on a Quadruped Robot by Reinforcement Learning
Authors: Wu Shangyu , Lei Xianqing , Ye Linqi
Published: February 2022

When a quadruped robot crosses some uneven terrain, its stability is a very important consideration. In practical applications, it is often difficult for researchers to obtain accurate models of quadruped robot systems and need quadruped robots to complete high-stability tasks. Balancing an inverted pendulum on a quadruped robot is a good way to test their balancing ability, which is of great research and practical value. According to the nonlinear, uncertain, and strong coupling characteristics of the quadruped robot inverted pendulum system, this paper proposes a quadruped robot balancing inverted pendulum algorithm based on reinforcement learning, the Q-learning algorithm. The advantage of this algorithm is that it can learn effective balancing policy directly from experience, and it does not depend on the accurate model of the quadruped robot. It has the characteristics of high efficiency and flexibility. Through a lot of training, it can break through the performance limit brought by model error to traditional methods. In this paper, a comparative experiment of a set of balanced inverted pendulums of quadruped robots with different sizes is completed in the V-REP simulation software. The experimental results show that the algorithm can effectively improve the balance ability of quadruped robots, and it also shows that the algorithm has good adaptability.
Design and Dynamic Analysis of Cleaning Robot for Cement Silos
Authors: Yang Jingkang , Duan Mingde , Zhang Bo , Shi Huadong
Published: February 2022

Aiming at the mechanization and automation of cleaning the hardening on the wall of the cement silo, a silo cleaning robot is designed. The kinematics and dynamics mathematical models of the cleaning robot are established respectively. With the 12000mm diameter silo as the cleaning object, the dynamics model is constructed with virtual prototype. There is an analysis of the relationship between the angular velocity and angular acceleration of the mechanical arm, and the relationship between the thrust of the cylinder over time were analyzed. The results show that the calculation results of the mathematical model and the simulation model are close, the change trend is consistent, and the movement is stable and meets the design requirements, which verifies the correctness of the mathematical model. The research results provide a theoretical basis for the next step of control system design and strength analysis. This silo cleaning robot solution can be extended to the cleaning construction of other silos such as coal bunkers, granaries and ore silo.
Investigation on vibration of Centrifugal Pump by Bearing supported position
Authors: Sun Tao , Liu Songge , Yu Wanbo , Shi Zhenyi
Published: February 2022

Vibration is one of the main problems which should be considered seriously in designing and operating a marine centrifugal pump to decrease vibration for the reliability of equipment and safety of ship. The reduction for vibration also can provide a guarantee for enhancing concealment, which will be benefit for military ships with higher requirements for concealment to improve combat effectiveness. A numerical calculation model of whole centrifugal pump was established in this paper. The emphasis of this article is that influence of bearing supported position on vibration of centrifugal pump. And conclusion was obtained that vibration peak can be reduced through adjust supported position of bearing reasonably. The simulation results was proved by experiment which was carried out in the Shaking Table Test.
Effect of micro-arc oxidation coatings with different thickness on high cycle fatigue performance of Ti-6Al-4V titanium alloy
Authors: Ba Hongbo , Fu Yuzhu
Published: February 2022

Micro-arc oxidation (MAO) coatings with 2 μm, 5 μm and 10 μm in thickness were produced on Ti-6Al-4V titanium alloy by MAO treatment, and the effect of coating thickness on the high cycle fatigue property was investigated. The microscopies and phases of coatings were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. The results indicated that the coatings were mainly composed of anatase TiO2. The MAO process generated micro pits at the substrate surface. The micro pits played a role of the notches, which induced the crack initiation during fatigue loading. The fatigue life of samples decreased with the increase of coating thickness. The micro pits were the main factor for the decrease of the fatigue life.
Compact-design, Modeling and Simulation of the Internal Permanent Magnet of Magnetically Guided Capsule Endoscope
Authors: Zhang Guanqing , Yin Ruixue , Wang Kemin , Zhang Wenjun
Published: February 2022

Miniaturization is a challenge for the magnetically guided capsule endoscope (MGCE), especially considering the multifunction of MGCE. This paper proposes a compact-design of internal permanent magnet (IPM), which contributes to the miniaturization of MGCE. The IPM is a complex of actuator and shell of the MGCE, which frees the occupation of conventional IPM. The IPM is for the first time designed with a streamline shape for good kinematics. A magnetic propulsion model of the proposed IPM is established and a magnetic propulsion simulation based on finite element (FE) and boundary element (BE) analysis for guaranteeing steady locomotion and navigation is conducted. The simulation is validated by comparison of the analytical model. At last, the locomotion modes and navigation of IPM are simulated based on the justified simulation. In conclusion, the compact-design of IPM can guarantee the locomotion and navigation of MGCE, and increase the available inner space of MGCE.
Experimental on the vortex induced motion suppression of floating spar-type wind turbine
Authors: Xiao Yanghong , Fu Chunli , Bai Xinlan , Li Lei
Published: February 2022

To investigate the suppression performance of the spar-type wind turbine vortex induced motion(VIM) with the addition of splitter plate, VIM model tests were carried out in a circulating water channel. Two different splitter plates width conditions were tested. In all the conditions, the cylinder was free to oscillate with one DOF. Results regarding response amplitudes and characteristic frequencies were presented and discussed. There was no obvious lock-in phenomenon on the vortex excitation motion of the cylinders with splitter plate, only some synchronization was observed. W/D=0.2 has better suppression performance than W/D=0.4 in vortex induced motion.
Research and Analysis Based on Three-dimensional Precision Inspection Process Planning Technology
Authors: Sun Ri , Bai Yuewei
Published: February 2022

Three-dimensional precision inspection has the characteristics of digitization, completeness, and timeliness. The manufacturing industry needs to research and improve the existing inspection process planning technology. Carried out research on the key technology of three-dimensional inspection process planning, including inspection information extraction, inspection point planning, path planning, etc., compared and analyzed the offline inspection technology represented by the coordinate measuring machine and the online inspection technology represented by the machining center. Studied and analyzed the system architecture, main functional modules of process planning software tools for these two types of inspections; finally, it looks forward to the future development trend.
Experimental research on terahertz scanning imaging system based on S-parameters
Authors: Zhang Yanbo , Li Xiangdong , Zhao Xingwen , Tian Xianzhong , Yang Zijiang
Published: February 2022

Due to the limitations of the detector in the terahertz (THz) scanning imaging process and the problems of low contrast and poor visualization effect of original image, a THz continuous-wave scanning imaging system from 75 to 110 GHz is presented. The system is comprised of vector network analyzer (VNA), spread spectrum module, transmit and receive antennas, scanning stage and host computer. In addition, the automatic acquisition and storage of S-parameters is realized by Virtual Instrument Software Architecture (VISA) protocol, and the gray imaging method based on S-parameters is proposed. High-precision structural resolution test board is designed based on printed circuit board (PCB) method and the imaging experiment for the resolution test board is carried out. By comparing with original imaging results, better imaging quality of the system designed in this paper is obtained and imaging results show that the resolution of 1.8 mm could be achieved.
Research on Simulation Experiment Method and Process in Joint Operations System
Authors: Kong Chenyan , Chu Wei , Ju Zhenqi
Published: February 2022

To meet the requirements of joint operations simulation experiment, a framework of joint operations simulation experiment is proposed, design elements in basic scenario before the experiment, design and screening method of experiment factors, characteristics and modeling elements of simulation models during the experiment are studied particularly, and the optimal control flow of the experimental process is designed
Spatio-temporal coverage planning algorithm for multi-UAV and multi-sensor cooperative search
Authors: Zheng Deyan , Liu Chunhui , Huang Lizhen
Published: February 2022

A spatio-temporal coverage planning algorithm for multi-UAV and multi-sensor cooperative search is proposed in this paper, named STC-MARL, which is based on multi-agent reinforcement learning and allows several UAVs equipped with two types of sensors to learn to complete full view of a field of interest (FOI). The proposed STC-MARL algorithm can make participating UAVs to learn from the environment to complete the full coverage of a specific FOI while minimizing field of views (FOVs) interacted with each other. The experimental results show in detail with simulation that the UAVs in the mission can effectively accomplish the task of spatio-temporal coverage planning.
Research and analysis of infrared image enhancement algorithm based on fractional differentiation
Authors: Lou Junyi , Ji Jiajia , Zhou Qin , Li Xi
Published: February 2022

Due to the inherent defects of infrared imaging systems and the influence of the external complex environment, infrared images have low contrast, blurred edge details, low signal-to-noise ratio and poor visual effects compared with visible images, which have a great impact on the subsequent feature extraction, detection and identification and target tracking, and cannot meet the requirements in military, medical and civilian fields. The current technical deficiencies of infrared imaging devices at the hardware level cannot fundamentally solve these problems, so it is especially necessary to enhance infrared images from the perspective of algorithms. We propose an improved fractional differentiation algorithm that enhances the contrast of infrared images and the contrast of the images is controlled by the fractional order. Experiments and analysis show that the proposed method has good feedback for enhancing the contrast of dark images, and it can effectively enhance the edge information and detail information.
Image defogging system and algorithm research based on MATLAB platform
Authors: Chen Yongchang , Sun Xiangrui , Qiu Xiaofeng , Wang Xinyan
Published: February 2022

Since the Reform and Opening up, the characteristics of China’s high-quality economic development have become more distinctive, the adjustment of economic and social structure has been continuously optimized, the kinetic energy has been continuously enhanced, and the degree of industrialization has been significantly improved. However, it has also caused some environmental problems, and haze pollution is one of them. The haze weather with low visibility has a certain impact on people’s daily travel, transportation and navigation. Because the images taken under the haze condition will be degraded to varying degrees and the image details will be lost, the effect of identifying and processing the degraded images in the later stage will be reduced. Therefore, in order to clear and restore the degraded image, we developed a defogging system based on MATLAB software. The system mainly uses histogram equalization, MSR and dark channel a priori defogging algorithms to restore fog degraded images. The results indicate that various defogging algorithms are able to enhance the clarity of the picture to varying degrees. The successful implementation of the defogging system lays a theoretical foundation for the in-depth research and application of fog image defogging processing technology, and has good technical operability.
Research on optimization method of routing buffer linkage based on Q-learning
Authors: Han Zhonghua , Qi Hongfeng , Chang Daliang , Gong Wei , Dai Shilong
Published: February 2022

According to the characteristics of the painting process of passenger car manufacturing enterprises, by formulating the routing buffer linkage rules based on the total renewal cost, the linkage process of the bus in the routing buffer is controlled, and an improved Q-learning (Q- The routing buffer of learning) algorithm quickly finds the optimal path method. According to the actual production situation, this method improves the dynamic parameters of the algorithm on the basis of the traditional Q-learning algorithm, and improves the optimization speed and accuracy of the algorithm by establishing the correlation between the work-in-process and its neighboring work-in-process in the current state. Through multiple sets of example simulation tests, the effectiveness of the Q-learning algorithm in solving the optimization problem of routing buffer linkage is verified.
Research on prefabricated component production line mold platform combination method
Authors: Han Zhonghua , Yu Lingfeng , Li Bo , Qi Yuanwei
Published: February 2022

In traditional prefabricated component manufacturing enterprises, there are often problems such as low utilization rate of the platform surface due to poor production plans of the enterprise, resulting in waste of production resources and low production capacity of the enterprise. In order to solve the problem of mold platform combination allocation in the production process of prefabricated component manufacturers, a mold platform combination allocation method based on the combination of machine learning and backtracking is proposed. The backtracking method is used to search for the theoretical best fit combination result, and the improved BL is used. The positioning algorithm simulates the placement process of the mold on the platform, and uses the Apriori algorithm to train the obtained data set to obtain the association rules contained in the frequent item set. When the enterprise re-produces, the prefabricated components are combined according to the association rules for production, and the utilization rate of the platform is improved. The simulation test is carried out with the example data of the prefabricated component manufacturing enterprise, which verifies the effectiveness of the combination allocation method of mold and platform combined with the backtracking method and the Apriori algorithm to solve the problem.
Research on the Test-times Selection Method for the Accuracy Evaluation of Inertial Navigation System
Authors: Wang Dan , Yang Gong-liu , Li Mingming , Luo Yong
Published: February 2022

Aiming at the unreasonable test-times selection method in the precision evaluation of inertial navigation system, this paper puts forward the test-times selection method. The test conclusion confidence, test condition confidence, and the sample confidence limit are included in this test-times selection method for quantitative test-times. In addition, the selection process is illustrated through an example.
Partial discharge detection and type identification of typical defects of XLPE cables under AC voltage
Authors: Liu JiaXin , Wei DeFu , Zhao ZhenWei , Zheng WeiGang , Cui JuYong
Published: February 2022

According to the discharge characteristics of the typical defects of power cables, four common physical models of cable simulation defects are designed and produced under laboratory conditions. The high-frequency current method is used to measure the discharge signals of the four common cable simulation defect models, the data is collected and stored, a two-dimensional discharge map is drawn, and the support vector machine method (SVM) is used for classification.The results show that: the signal distribution range of levitation discharge is the widest, and the signal distribution is long; the tip discharge only generates the discharge signal in the negative half of the cycle; the negative half of the creeping discharge is more dense than the positive half of the cycle; the number of discharges in the positive and negative half of the internal air gap discharge is roughly the same ; discharge of different types of defects is obviously different. Extracting statistical features from its two-dimensional spectrogram for identification, the identification accuracy rate is above 90%, and different types of defects can be effectively identified.
DOA estimation based on density-tapered thinned array
Authors: Tian Jiahao , Zou Yimeng , Zhang Yongsheng
Published: February 2022

In this paper, several classical DOA estimation methods are applied to density-tapered thinned array. The density-tapered thinned array has the advantage that there is no grating lobe in the whole angle scanning range, and the unambiguous angle estimation of the target is obtained. The experimental results show that the classical DOA estimation method can be applied directly to the density-tapered thinned array to obtain satisfactory results, which lays a foundation for the practical application of the density-tapered thinned array. In addition, the effects of sparsity and number of elements on DOA estimation are analyzed, and the advantages of density-tapered thinned array over uniform arrays are verified.
Research on Multi-step Mixed Predictiom Model of Coal Gasifier Furnace Temperature Based on Machine Learning
Authors: Zhao Yanbin , Ma Zhongbin , Han Xuefeng
Published: February 2022

In order to ensure the safe and stable operation of the coal gasifier, it is particularly important to study a new and reliable method for predicting the temperature of the gasifier. In this paper, the coal gasifier furnace temperature prediction is transformed into a time series prediction problem, and according to the non-linear characteristics of the gasifier furnace temperature data set, the LSTM (Long Short-Term Memory) model in the machine learning algorithm is selected for the gasifier furnace.Then use the PSO (Particle Swarm optimization) algorithm to optimize the hyperparameters of the model. The results show that the LSTM model is feasible but the accuracy is slightly lacking. The prediction accuracy based on the POS-LSTM model is significantly improved. It is of great significance to accurately predict the temperature of the gasifier.
Study on the PI/SPEEK nanofiber composite proton exchange membrane for fuel cells
Authors: Wei Peng , Huang Dong , Li Xi , Zhu Bensheng , Cong Chuanbo , Meng Xiaoyu , Zhou Qiong
Published: February 2022

Sulfonated poly ether ether ketone (SPEEK) can be selected as the candidate for proton exchange membrane (PEM) used in the fuel cell for its cheap price, great proton conductivity and stability. To further improve its performance, more SO3H were induced into SPEEK but would result in excessive swelling and losing its stability. Polyimide (PI) nanofibers have excellent mechanical properties and can be a supporter to improve stability. In this work, the PI nanofiber was put in the middle of the SPEEK to create the PI/SPEEK nanofiber composite membranes (NCMs). Its morphology of PI/SPEEK NCMs observed by SEM showed that PI nanofiber was almost in the middle of these NCMs. The proton conductivity and swelling ratio of 3%PI/SPEEK were 271.7 mScm-1 and 20.0% at 60°C and 100% RH, which is 29.6% higher and 90.4% lower than that of pristine SPEEK. It was intact after the single-cell test in the fuel cell and its power density was 199.1 mWcm-2, but for pure SPEEK there was some broken area on it. The reason was that PI/SPEEK can maintain the durability of the channels for the proton to transport and it can be attributed to an interaction at their interface of PI nanofiber and SPEEK. The 3%PI/SPEEK NCM will have a broad application prospect in PEM fuel cells.
Analysis of engineering application requirements of nano coating materials
Authors: Zhong Wenan , Zhang Dongjiu , Wang Yuchao , Zhao Yu , Liu Jianfeng
Published: February 2022

Coatings are the primary means to control the corrosion of marine engineering structures. It is the frontier and hot spot of nano coating materials research to use nano materials to modify anti-corrosion coatings, realize the complementary advantages between different materials, and prepare high-performance, environmental protection, energy saving and functional anti-corrosion coatings. However, with the application of nano coating materials in the atmospheric subtropical coastal environment, there are many problems of poor weatherability. Based on the environmental corrosion characteristics of the subtropical coastal zone, this paper evaluates the environmental adaptability of several nano coating materials in the coastal atmospheric environment, analyzes the engineering application requirements of nano coating materials, and puts forward the measures and suggestions for the development of nano coating materials in marine engineering in view of the main problems existing in the engineering application of nano coating materials in China.
Research and application of polymer-surfactant binary combination flooding numerical simulation
Authors: Zhang Yanyu , Luo Zhaowen , Xie Mengke , Teng Zhiyi , Wang Yue
Published: February 2022

At present, many oilfields in China have entered the stage of high water cut development, and the research on the methods of improving oil recovery has been paid more and more attention. Among them, the application of binary combination flooding is more and more extensive. In view of the target area, based on the fine geological modelling, this paper establishes a binary combination flooding model considering the influence of surfactant on oil-water interfacial tension, the adsorption of surfactant by rock, the shear and degradation of polymer, and the adsorption of polymer by rock. Based on the matching of reserves and production history, the development schemes under different development methods are designed and the development effect is predicted and evaluated, the influence of development mode, injection time and injection-production speed on development effect is also studied. The results show that the development effect of binary combination flooding is the best, which provides a theoretical basis for the subsequent efficient and reasonable development of the block.
Molecular Dynamic Simulation in Organic Semiconductor Investigation
Authors: Gu Junwen
Published: February 2022

The details of charge transfer events inside the organic semiconductor puzzled researchers for many years. This paper focuses on the simulation method’s capability to investigate on polaron’s properties and insights about charge transfer events inside the organic semiconductors. The paper adopts a molecular dynamic simulation method called LMD simulation from the journal of chemical science to model the charge transfer between pairs of fullerene molecules. By performing the simulation, the paper analyzes and evaluates the results it gained and concludes, by showing a large-scale investigation capability and accurate details for a single event, the molecular simulation is capable to study the charge transfer events of semiconductors.
Study on Compatibility of Waterborne Surface Treatment Coatings
Authors: Li Wenbo , Yang Yingfei , Song Dongdong , Zhu Jiran , Xie Yi
Published: February 2022

the severe corrosion of power grid equipment has always been an important factor affecting the service life of equipment. Rust transfer technology is used to treat the corroded equipment to improve the corrosion resistance of transmission grid cabinet equipment in high temperature and high humidity environment. Taking acid modified acrylic acid as the main component, the composite conversion solution was obtained by adding phosphoric acid and phytic acid. Through the surface morphology, electrochemical test and adhesion test after rust conversion, the universality and corrosion resistance of the rust conversion solution were analyzed; Combined with zinc phosphate primer and zinc rich primer, the effects of rust conversion solution on the adhesion and salt spray corrosion resistance of the two commercial primers were studied. The compound conversion solution has good rust conversion effect on atmospheric corrosion rust layer, salt spray corrosion rust layer and damp heat corrosion rust layer; The corrosion resistance and adhesion of atmospheric corrosion rust layer are obviously improved after being treated with rust conversion solution. The adhesion of zinc phosphate primer and zinc rich primer on rust conversion solution is 2.1 times and 0.8 times higher than that of atmospheric corrosion rust layer without rust conversion, respectively. The compound rust conversion solution has strong universality and can convert atmospheric corrosion, salt spray corrosion and damp heat corrosion rust layers. At the same time, it has good corrosion resistance, which can significantly improve the corrosion potential of the corroded surface and reduce the corrosion current density. In addition, the composite rust conversion solution can significantly improve the adhesion and corrosion resistance of the primer coating.
Research of Water Vapor Barrier Property Testing Methods for Hollow Containers
Authors: Li Meng , Liu Lina , Wang Jinxiu , Wang Shifeng , Mao Weichang , Chen Xin
Published: February 2022

Barrier property is a characteristic of hollow containers and can be used to meet the need for shelf life of the contents; the hollow container shape is variable, which makes it difficult for overall barrier property testing. Based on this, this paper discusses the common testing methods of water vapor barrier property of hollow containers. Firstly, the advantages and disadvantages of the traditional weighing method and sensor method in testing the water vapor barrier property of containers are compared, typical applications are taken as an example, and finally two new methods, namely electrolytic sensor method and infrared sensor method, which can quickly and accurately test the moisture permeability of hollow containers, are introduced in detail, so as to achieve good and accurate test for various hollow containers, which can provide reference for related industries in selecting testing technologies for container barrier property.
Synthesis Methods and Influencing Factors of Metal Organic Framework Material MIL-53
Authors: Li Fangqin , Wang Guanjun , Ren Jianxing , Sun Chenhao
Published: February 2022

Regarded as brand-new porous material, metal organic framework(MOF) has a certain ability to remove pollutants due to its high porosity, high specific surface area, adjustable micropore size and easy functionalization. Compared with other metal organic framework materials, MIL-53 has a relatively higher specific surface area and stronger hydrothermal stability, which leads to excellent performance and application prospects in the removal of pollutants. In this paper, synthesis methods of metal-organic framework material MIL-53 are introduced, and the influencing factors in the synthesis process using hydrothermal method are discussed, including the component ratio, type of organic solvent and pH value. Due to less dependence on residence time and organic solvent, mechanical method can reduce energy consumption and has latent value for future application. Among different influencing factors, reducing the pH of solution when synthesizing MIL-53 using hydrothermal method seems to save time and achieve rapid formation.
Study on Synthesizing Polycarbonate with Triphosgene
Authors: E Yongsheng , Lv Ping , Yang Fang
Published: February 2022

Polycarbonate is a widely used thermoplastic engineering plastic with excellent properties. Using triphosgene and Bisphenol A as raw materials, polycarbonate is synthesized by interfacial polycondensation. The effects of catalyst dosage, molar ratio of raw material, reaction temperature and reaction time on the molecular weight of the product are investigated, and the optimal reaction conditions are obtained. The structure of the product is verified by infrared absorption spectroscopy. The rotary viscometer measures the intrinsic viscosity of the sample and calculates the viscosity average molecular weight of the sample to be 50000. The glass transition temperature of the product is detected to be 148.5 °C by dilatometer. The polycarbonate synthesized by the new method meets the quality requirements.
Preparation and application of low molecular weight polyether polycarboxylate superplasticizer
Authors: Liu Bobo , Ke Kuliang , Yang Yinggang , Miao Donghui , He Chong
Published: February 2022

In this paper, a low molecular weight polycarboxylate superplasticizer was designed and synthesized by using low molecular weight polyether macromonomer with molecular weight of 800 as the side chain of polycarboxylate superplasticizer; The ratio of oxidant and reductant in inorganic salt initiator system is 2:1, and that in organic water solvent initiator system is 4:1. The amount of initiator in the two systems accounts for 5% and 2% of the total amount of polyether macromonomer, respectively; GPC and Fourier transform infrared spectroscopy tests showed that the number average molecular weight of the water reducer was about 24000, the conversion rate of polyether macromonomer was more than 90%, and the molecular structure of the polymerization product met the design requirements. The influence of the polymer on the fluidity and bleeding rate of manufactured sand concrete is also discussed.