bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimization of injection parameters for temperature time response gel plugging agent
Authors: Yan Wei , Cao Ruibo , Ma Yingxue 
Published: December 2021

Abstract
Aiming at the temperature time response gel plugging agent developed by Daqing exploration and development institute. In this paper, the injection volume, injection speed and injection concentration are optimized. The experimental results show that: the temperature time response gel can achieve the best plugging effect under the injection volume 0.1PV, injection concentration 1000mg/L and injection speed 0.6ml/min. In the subsequent water injection stage, the conductivity of high permeability layer decreases from 72.7% to 0.7%, that of low permeability layer increases from 4.1% to 14.3%, and that of medium permeability layer increases from 23.2% to 85%.
Preparation and characterization of red mud based porous materials
Authors: Zhu Junge , Yue Hongzhi , Bai Rong , Zhu Jianping , Ma Laijun 
Published: December 2021

Abstract
China was a large country in bauxite mining and refining. One ton of alumina was produced, accompanied by 0.5 ~ 2 tons of red mud [1]. Therefore, the accumulation and pollution of red mud had been a difficult problem to be solved by enterprises and local governments. In this paper, red mud based porous materials were prepared with Bayer red mud, perlite, silicon carbide (as foaming agent) and glass powder (as flux). The effects of sintering process and iron oxide on thermal conductivity, bulk density, porosity and compressive strength of red mud based porous materials were studied by TG-DSC, XRD, SEM and XEDS. The results show that red mud based porous materials with uniform pore distribution could be obtained when the amount of red mud was 60%, perlite was 37%, SiC was 1%, glass powder was 2%, sintering temperature was 1150 °C and holding time was 120 min. The true porosity of the red mud based porous material was 70%, and the average pore diameter was 216.84 μ m. The thermal conductivity was 0.26w / (m • K) and the compressive strength was 2.31MPa.
Process Characteristics of Water-based Self-curing Coatings for Sand Casting
Authors: Bian Qingqing , Feng Shengshan , Dong Huang , Xie Shuzhong , Liu Chunjing , Zhan Chunyi , Chen Jianli , Wu Weifeng , Liang Jiahao , Gao Yunhua 
Published: December 2021

Abstract
The rheological and gas evolution characteristics of water-based self-curing coatings for sand casting were analyzed and the influence of coating-thickness and graded coating on self-curing rate of coatings was studied. It can be seen from the test results that: the new water-based self-curing coating has both the characteristics of thixotropic fluid and pseudoplastic fluid, which has moderate thixotropy rate and high brushing index, good brushability and excellent comprehensive balance of flow-levelling and anti-flowability. It can meet the rheological requirements of various coating methods. The self-curing speed of water-based self-curing coating increases in an approximately linear manner with the decrease of its thickness. Thick coating should be best to paint at one time in the premise of ensuring its surface quality. Although the gas evolution volume of the new water-based self-curing coating is approximately equal to that of ordinary water-based baking coatings, but the gas evolution speed of self-curing coatings is almost half as that of the latter, which provides good conditions for preventing gas hole defect of casting.
Research on Discrimination Threshold of Brightness for Different Color Temperatures
Authors: Ju Jiaqi , Xu Ting , Xu Ke , Jin Yan 
Published: December 2021

Abstract
This article explores the experimental study on the relationship between human eye discrimination threshold of white light under different lighting levels and color temperatures by the psychophysical experimental method. The visual matching method was applied to study the subjective brightness perception under different lighting environments. We try to explore the internal connection between the physical intensity and subjective rating value. The experimental results will do help the development of dimming system for smart lighting.
Autocorrelation Measurement of Picosecond Pulses with Two-Photon Absorption
Authors: Chen Junbao , Yang Yitao , Qiu Mingyue 
Published: December 2021

Abstract
In this work, an autocorrelation measurement method is proposed to obtain the key information of picosecond pulses using the two-photon absorption (TPA) effect. The autocorrelation measurement process is simulated with a linear tuning of the pulse repetition frequency (PRF). Given the dispersion of picosecond pulses, the profile of the autocorrelation signal is broadened symmetrically. Moreover, the dispersive distribution in time-frequency domain of picosecond pulses and the different bandwidth of the TPA spectrum of materials should bring in sub pulses in the autocorrelation signal with the relative different delay. As shown in simulations, with an ideal broadband two-photon response spectrum, only the broadening of autocorrelation trace appears. But the detection with a narrowband two-photon response spectrum displays the greater sensitivity for pulse dispersion of the edge of the pulse, benefiting from the more sub pulses. Detections of picosecond pulses within the space wireless communication band region generally employ the photoconductive antenna and electro-optic effect in free space. However, with respect to the TPA effect in the specific materials, we could build an extremely compact autocorrelation measurement configuration for the key information extraction of picosecond pulses in space wireless communication and astronomical measurement, which would provide the same information as conventional detections about the autocorrelation signal of picosecond pulses.
Effects of the Photoelectrochemical Etching in Hydrogen Fluride (HF) on the Optoelectrical Properties of Ga2O3
Authors: Hao Yuhua , Wang Xia 
Published: December 2021

Abstract
Photoelectrochemical (PEC) etching is preferred to produce micro-and nano-structures for constructing Ga2O3-based electronics and optoelectronics, owing to its numerous controllable parameters. During the devices fabrications, beyond the wet chemical and dry (plasma) etching produces, PEC etching also leads to device degradations inordinately. In this work, the Ga2O3 thin film was PEC etched by hydrogen fluride (HF) etchant, and its opto-electric deep-ultraviolet sensing performances, including photo-to-dark current ratio, responsivity, and response speed, before and after PEC etching were analyzed and discussed.
Optical Design of Improved Offner Imaging Spectrometer
Authors: Song Chong , Huang Yong , Yan Yangdong , Cui Dongsen , Wang Gang , Niu Yanting , Liu Bijun 
Published: December 2021

Abstract
An improved Offner imaging spectrometer was proposed based on the optical system characteristics of Offner imaging spectrometer, which can ensure perfect imaging quality in a wider annular region. The operating wavelength of the improved Offner imaging spectrometer ranges from 900nm to 1700nm, and the magnification is 1. Improved Offner imaging spectrometer can be obtained by changing the meniscus lens position and further optimizing the design. The results indicate that the improved Offner imaging spectrometer can effectively improve compactness and lightweight, and reduce the difficulty of optical adjustment, which is conducive to the stability of practical application.
Haze-day Trends from 2013 to 2020 and Analysis of Spatiotemporal Characteristics of a Haze Process in Ningbo, China
Authors: Hu Lijun , Gao Aizhen , Yang Hao , Zheng Zheng 
Published: December 2021

Abstract
Air quality in Ningbo continues to improve with a constant decrease in the PM2.5 concentration. However, pollution levels occasionally increase during autumn and winter. To understand the regional and seasonal distributions and the interannual variation during haze days, we analyzed the haze monitoring data from 2013 to 2020 and the haze weather process during January 18–19, 2016. Our results showed a downward trend in the major pollutant concentrations. High PM2.5 concentrations persist in certain areas of Ningbo during winter owing to seasonal haze conditions. However, the annual number of haze days has decreased between 2013 and 2020. Regional variations in pollutant concentrations appear mainly in winter, especially in December and January. The observed concentrations were higher in the north and west, and lower in the south and east. The haze process during January 18–19, 2016, occurred within a height of 0–1.5 km, with high PM2.5 concentrations mainly occurring as small and spherical particles. A higher relative humidity, temperature drop, and stable weather assist in accumulating and sinking pollutants, which cause long-term effects and render diffusion difficult. Although recent national initiatives have been effective, the air quality in northern Ningbo requires further improvement during autumn and winter.
The Influence of Noise in the Super-Resolution Reconstruction of Structured Illumination Microscopy
Authors: Bai Jinxi , Shi Zhendong , Ma Hua , Liu Lijia , Zhang Lin 
Published: December 2021

Abstract
As one of the mainstream super-resolution imaging technologies, structured illumination microscopy (SIM) is popular for its fast imaging speed and simple optical path structure. Spectrum separation is a key step in the reconstruction of super-resolution images. However, in the process of imaging, the unavoidable noise will seriously affect the accuracy of frequency spectrum separation. This paper carries out a simulation study on the influence of noise in the process of frequency spectrum separation. The results show that although noise can cause distortion of low-frequency information in frequency spectrum separation results, it has little influence on high-frequency information. Therefore, a super-resolution image reconstruction method is proposed to effectively suppress the influence of noise. Both simulation and experimental results are shown the method can suppress the influence of noise without losing the details of super-resolution.
Joint Monitoring and Analysis of Sea Fog Using Dual Visibility Lidar in Ningbo, China
Authors: Hu Lijun , Yang Hao , Wang Hao , Ren Xinyue 
Published: December 2021

Abstract
Visibility lidar has obvious monitoring advantages over forward scatter visibility sensors or fog droplet spectrometers; it can measure visibility information over a large area. In 2021, two visibility lidar instruments (1064 or 532 nm wavelengths) were installed in Beilun, Ningbo Zhoushan Port, to monitor sea fog. Comparing their monitoring data to those of forward scatter visibility sensors and a fog droplet spectrometer revealed that the visibility lidar instruments could obtain energy progress information section-by-section in the monitoring path, and could directly reflect sea fog changes. The 1064 nm lidar outperformed the 532 nm lidar regarding sea fog detection. The effective detection range decreased significantly with decreasing visibility; the reliability decreased in low-visibility, uneven atmospheres. In a low-visibility but uniform atmosphere, however, lidar data corresponded well with forward dispersion data. The 532 nm and 1064 nm lidar data sometimes differed at the same monitoring position owing to differing heights and particle reflection angles. During a sea fog event on May 9, 2021, the maximum droplet concentration was 14 cm−3, the maximum liquid water content was 0.21 g·m−3, and the maximum equivalent diameter was 49 μm. The formation of this sea fog was dominated by large particles.
Active Disturbance Rejection Control Based Feedback Control System for Quasi-Continuous-Wave Laser Beam Pointing Stabilization
Authors: Li Wenjun , Zhang Lin , Guo Yading , Chen Zhongzheng , Shao Chongfeng , Li Yang , Chang Jinquan , Chen Na , Wang Xiaojun , Bo Yong , Peng Qinjun 
Published: December 2021

Abstract
Because of the significant nonlinearity of fast steering mirror (FSM), which is actuated by lead zirconate titanate (PZT) stacks, designing a high-performance laser beam pointing stabilization system is always a difficult work. This paper reports an active disturbance rejection control (ADRC) based feedback control system for laser beam pointing stabilization of a high-power quasi-continuous-wave (QCW) Nd:YAG slab laser with a repetition frequency of 160 Hz and an average output power of 1.5 kW. The simulation and experiment show that the ADRC is faster and smoother than traditional proportional-integral-differential (PID) control, and the ADRC can effectively reduce overshoot in the laser beam pointing stabilization process.
Representative Construction Engineering Drawings Combining SLAM and Ground-Based LiDAR
Authors: Gao Chutian , Guo Ming , Fu Zexin , Li Dengke , Ren Xian , Sun Mengxi , Zhou Yuquan , Cheng Peng 
Published: December 2021

Abstract
Obtaining architectural engineering drawings is a crucial aspect of upgrading and repairing structures. Traditional elevation measuring is ineffective and results in a poor rate of restoration. The current building elevation measurement solutions based on 3D scanning technology all obtain building 3D point cloud data from a single type of laser scanner. These two methods can’t get both indoor and outdoor scenes at the same time. This paper presents a scanning strategy that combines SLAM with Ground-based LiDAR to solve this problem. The point cloud data for the building’s indoor and outdoor scenes are obtained independently, and the Ground-based LiDAR point cloud data is registered locally using the iterative closest point(ICP) algorithm. The SLAM point clouds and the Ground-based LiDAR point clouds are then registered as a whole to develop an overall model of the building using point constrained error equations. For various reasons, the building can be trimmed into a planar point cloud model depending on the application. Finally, engineering drawings for the construction of the building can be drawn. The method’s viability was demonstrated by using it in a 3D scanning project of a scenic site in Beijing. This technology improves model information interpretability, scanning efficiency, and provides powerful data assistance for building rehabilitation and repair. It is extremely important in the disciplines of urban planning, rehabilitation, and historic preservation. After performing a more optimal preprocessing, more than 90% classification accuracy was achieved across 18 low-power consumer devices for scenarios in which the in-band features-to-noise ratio (FNR) was very poor.
Design and simulation analysis of vacuum fish suction pump
Authors: Ding Ziyang , Xu Lingfeng , Gao Ming , Wang Guoqing 
Published: December 2021

Abstract
Most of Chinese aquacultural products rely on artificial nets to catch in 2020. Fish suction pump can replace artificial net, is an important mechanical equipment of fish breeding industry. The development of fish suction pump is relatively backward and the level of automation is still to be improved, which is not conducive to the large-scale and rapid development of aquaculture in various countries. This paper designs a single tank vacuum suction fish pump, the suction fish pump mainly uses the tank and the air pressure difference, through the automatic control system on the suction fish pump and each stage of the control, relying on the gravity of the mixture of fish and water to release fish. In this paper, fluent was used to conduct simulation analysis on the flow diagram of fish-water mixture inhaled at work, and the flow diagram and velocity vector diagram of the internal flow field were obtained. The results show that the vacuum fish suction pump can effectively reduce the fish collision damage. The vacuum fish suction pump designed in this paper can effectively complete the fishing work of cultured fish, with the characteristics of high efficiency and low damage, which can provide theoretical reference for the design of vacuum fish suction pump in the future.
Estimation of Vehicle Longitudinal Speed Based on Improved Kalman Filter
Authors: Zhang Qiang , Xiao Jun , Xi Xiuhao 
Published: December 2021

Abstract
Estimation of vehicle longitudinal acceleration is very important in vehicle active safety control system. In this paper, two driving conditions of a 4WD off-road vehicle are divided by vehicle signals such as steering angle. Under different working conditions, different estimation algorithms are adopted. In the straight driving condition, the longitudinal speed was estimated by adjusting the variance weight of acceleration Kalman observation noise based on kinematics method. For steering conditions, in order to obtain the longitudinal velocity at the center of mass, by dynamic method, a lateral state estimator was designed and tire sideslip dynamics was modeled. The CarSim-Simulink co-simulation results show that the proposed algorithm has high accuracy and strong practicability.
Internal Leakage Predicition of Hydraulic Spool valves Based on Acoustic Emission Technology
Authors: Song Fei , Peng Likun , Chen Jia , Wang Benmeng 
Published: December 2021

Abstract
In order to realize the nondestructive testing (NDT) of the internal leakage fault of hydraulic spool valves, the internal leakage rate must be predicted by AE (acoustic emission) technology. An AE experimental platform of internal leakage of hydraulic spool valves is built to study the characteristics of AE signals of internal leakage and the relationship between AE signals and leakage rates. The research results show the AE signals present a wideband characteristic. The main frequencies are concentrated in 30~50 kHz and the peak frequency is around 40 kHz. When the leakage rate is large, there are significant signal characteristics appearing in the high frequency band of 75~100 kHz. The exponent of the root mean square(RMS) of AE signals is positively correlated with the exponent of the leakage rate only if the leakage rate is greater than 2~3 mL/min. This find could be used to predict the internal leakage rate of hydraulic spool valves.
Design of the LADRC control system for gravimetric stabilisation platforms
Authors: Lin Enfan , Xu Jiangning , Wu Miao , He Hongyang 
Published: December 2021

Abstract
Aiming at the problems of strong non-linearity of gravimeter stabilisation platform system, poor robustness of linear PID control algorithm and non-adaptive control system. This paper designs a LADRC-based gravimetric stabilisation platform control system design and method based on the research of PID controller and ADRC control method, and gives the anti-saturation and anti-noise design applicable to it, and the simulation experiment shows that the method is feasible.
Magnetic Target Position Estimation Method Based on Prior Information
Authors: Sun Guangfa 
Published: December 2021

Abstract
Aiming at the problem of detection and location of magnetic targets in water beach, the acoustic magnetic composite detection method is studied. After the sonar obtains the image of the suspicious object in the target area, the magnetic target recognition and location are realized by using the abnormal magnetic field distribution data near the target area measured by the shipborne magnetic sensor and the multi-sensor information fusion method. A target recognition and location method based on a priori information is proposed to solve the problem that the measurement results of magnetic sensor can not fully reflect the influence of ferromagnetic target on the surrounding magnetic field due to terrain constraints. In order to make up for this lack of information, taking the sonar measurement results as a priori information, the hypothesis test method is adopted to make full use of all the measurement results of different types of sensors to realize the recognition and positioning of magnetic targets.
Study on dynamic characteristics of rotor-bearing system under pitching condition
Authors: Pu Songcheng , He Yumin , Yang Qijiang , Cheng Ming , Wang Yupeng , Wang Zheng , Lin Yaodi 
Published: December 2021

Abstract
In many cases, ships will encounter special conditions, such as bad sea conditions, and the effect of various disturbance factors, such as wind and waves, will cause low-frequency longitudinal and transverse rocking motion of ships. This would affect the rotor-bearing system of the power plant, which is directly attached to the hull of the ship, and would roll along with the hull in the same longitudinal and transverse motion. This will have a significant impact on the stability of the rotor bearing system of the ship power plant and the safety of the ship. In this paper, a rotor-bearing test rig is mounted on a multi-degree-of-freedom swing test rig simulating sea conditions. The multi-degree-of-freedom rocking test bed simulates sea conditions. The rotor-bearing test bed is equipped with an eddy current sensor and an acceleration sensor to obtain experimental data. The programmable loader is used to control the rotor speed so as to carry out the experiment process at different speeds. Finally, the dynamic characteristics of rotor-bearing system under swinging condition are obtained.
Solving Multiple Triggering Problem of Ultrasonic Distance Measurement by Debouncing
Authors: Xiang Zhenhua 
Published: December 2021

Abstract
In recent years, multiple measurement systems fusion technologies have developed rapidly. Ultrasonic ranging is paid much attention because it has the advantages of directly measuring short-distance targets, high longitudinal resolution, and a wide application range. However, when the ultrasonic distance measurement is carried out by assembling the circuit board, it is found that the switch is triggered multiple times, and the measurement data is inaccurate. This paper proposes a new method that adding debounce to improve the accuracy of measurement. Besides, Some suggestions are provided to decrease the operation difficulty in the actual measurement process. Based on the experimental result, the accuracy and efficiency of ultrasonic distance measurement are greatly improved via this method proposed in this paper. By the way, the single-chip computer simulation technology simulates the ranging phenomenon in the experiment.
Research on Frequency Characteristics of VSG Virtual Parameter Adaptive Control Strategy Based on Fuzzy Control Theory
Authors: Jin Jie , Li Lan , Yu Haiyang , Feng Shengzhou 
Published: December 2021

Abstract
Traditional virtual synchronous generators (VSG) control inverters. Inverter output frequency characteristic of the virtual inertia (J) and virtual damping (D) coefficient, and the virtual parameters need to be modified and adjusted according to the purpose. To solve this problem, this paper proposes a virtual parameter adaptive control strategy based on fuzzy control theory to adjust the frequency characteristics of VSG. MATLAB/Simulink is used to build a simulation model to verify the correctness of the proposed fuzzy control theory’s adaptive virtual parameter theory.
Development of a 125% Load Brake Test Instrument for Elevator
Authors: Zhang Pengzhao , Feng Shuangchang , Fang Liang , Liu Shengjie 
Published: December 2021

Abstract
In order to solve the problem of elevator braking test inspection, this paper combs the requirements of relevant national standards and inspection rules on braking performance, and develops an elevator braking test inspection instrument. With the help of the instrument, the elevator braking effect can be expressed quantitatively, and the inspectors can conveniently judge whether the braking test results meet the requirements of elevator inspection rules remotely. A way to standardize and rationalize the test is given. In order to solve the problem of elevator brake test inspection, this paper sorted out the national standards and inspection rules on braking performance, and developed an instrument of elevator brake test inspection. With the help of the instrument, we could quantitatively give the expression on the elevator braking effect, and the inspectors can conveniently judge whether the braking test results meet the requirements of the elevator inspection rules in the remote.