bluuebunny/crossref_metadata_2025 huggingface dataset:
An On-orbit Target Detection Method in Remote Sensing Images for Micro Satellite
Authors: Zhou Qihui , Cui He , Liang Shengming , Li Huiqin
Published: August 2021

Aiming at addressing the contradiction between the information timeliness and on-board computing capacity and data transmission capacity in on-orbit image processing system of small commercial remote sensing satellites, a convolutional neural network based target detection algorithm is proposed. The calculation amount of the model is optimized to 25MFLOPS by using transfer learning, sparse training and weight quantification, while the weight file data is reduced from tens of Mb to 0.5Mb, which makes it possible for small commercial remote sensing satellite to detect target on-orbit quickly, and meets the requirements of the timeliness of remote sensing information.
A Ship Radar Matching Method Based on Target Attributes and Point Pair Topological Characteristic
Authors: Wang Jianan , Wu Bo , Wang Zhaojun , Yao Nana , Wu Jiajun , Gao Yue
Published: August 2021

We introduce a new ship target association method called SRM-AT, which stands for a Ship Radar Matching Method Based on Target Attributes and Point Pair Topological Characteristics. Using the radar properties of electromagnetic signals, as well as the longitude and latitude coordinates of electromagnetic signals and remote sensing images, this method calculates the point pair properties probability and PPTC (Point Pair Topological Characteristic) probability of electromagnetic signals and remote sensing images, as well as the syntheses of BPAF (Basic Probability Assignment Function) of the two through D-S evidence theory, to update the probability matrix of target association between electromagnetic signals and remote sensing images by using probability relaxation labelling method iteratively. The main contributions of this paper are: firstly, using decision trees to classify electromagnetic signals; finally, at the same time applicable to electromagnetic signals and remote sensing image ship formation and non-ship formation form. Through comparative experiments, this paper verifies that the method in this paper is superior to the comparative method in terms of association accuracy.
A Hyperspectral Image Classification Method with CNN Based on attention-enhanced Spectral and Spatial Features
Authors: Zhang Yangming , Yang Kun , Yuan Lei
Published: August 2021

In recent years, the convolutional neural network (CNN) has had a wide application in hyperspectral image (HSI) classification. HSI has many spectral and spatial features, which is well known that different spectral bands and spatial positions in the cubes have different discriminative abilities. Therefore, this paper proposes a classification method with CNN, which uses attention-enhanced spectral and spatial features (CNN-ASS). First, we use spectral and spatial subnetworks to extract spectral and spatial features. At the same time, spectral attention and spatial attention are added to the two subnetworks, respectively. Then, we sum the weights of the classification results of the two subnetworks to get the final classification result. This paper conducts experiments on three typical hyperspectral image data sets, and the experiment results show the CNN-ASS has a competitive advantage compared with some advanced methods.
Power Internet of things communication management platform adaptation scheme
Authors: Chen Baoren , Hong Danke , Wang Li , Ou Yongtong , Zhong Xinhui
Published: August 2021

Absrtact: There are a large number of power system equipment. The realization of smart grid requires effective collection and comprehensive judgment of the information collected and transmitted by many scattered equipment. Wireless communication technology plays an important role in it. The information interaction of each intelligent device needs to adapt to different platforms and protocols. This paper analyzes the problems existing in the current power peer platform, and provides corresponding strategies and solutions for the construction of intelligent power Internet of things communication platform, so as to efficiently realize the adaptation of platforms, systems and protocols, and realize the unified access and effective management of devices.
A Self-adjusting Online Map Matching Method
Authors: Lv Weijia , Chen Yi , Shang Pengfei , Zheng Fang , Wang Jielong
Published: August 2021

With the rapid development of intelligent transportation systems (ITS) and location-based services (LBS), it is more important to match the original trajectory sequence generated by users/vehicles to the actual road network. Most of the existing online map matching algorithms are based on the idea of local processing, or require richer data input and more mathematical models to ensure matching accuracy. This paper presents a simple and effective map matching method, called self-adjusting online map matching (AOMM). The algorithm is developed based on hidden Markov model (HMM). Considering the topological and geometric properties of the road network, the emission probability and transition probability calculation formulas of HMM are defined. And three adjustment strategies are provided to deal with trajectory noise points, dense trajectory points, and offset trajectory points. The algorithm only needs latitude and longitude information of trajectory points, and can match point by point. Experimental results on open trajectory data show that the algorithm has high matching accuracy and low output delay, and can meet the requirements of general online map matching tasks.
Characteristics analysis of regional geological hazards based on spatial distribution of potential hazards
Authors: Wang Jing , Zuo Qionghua , Huang Qinhui , Ying Xi
Published: August 2021

The regional disaster scenario can be described by the disaster consequence and its evolution trend: the state of the disaster bearing body directly reflects the disaster consequence, and the relationship between the disaster bearing bodies leads to the complex and diverse evolution trend of the disaster consequence. Therefore, taking the disaster bearing body and its association as the core, a network model reflecting the characteristics of the disaster affected area is constructed to describe the regional disaster scenario. Based on the spatial distribution of potential hazards, the characteristics analysis method of regional geological hazards is proposed. This paper analyzes the regional elements of scenario architecture from a systematic point of view. Based on the evolution attribute of disaster bearing bodies, the influence range model of disaster bearing bodies and the influence topological association between them are defined, and the generation method of association network model of regional disaster bearing bodies is proposed. Using this method to construct disaster scenarios reflecting the characteristics of the affected area in advance is conducive to the assessment of the risk of regional disaster loss in advance.
High Resolution Remote Sensing Image Classification Algorithm Based on Improved FCN
Authors: Yunbo Kong , Haojun Fu , Yangfan  , Zhouhai  , Na Wen , Fan Zhang
Published: August 2021

Aiming at the problems of less bands of high resolution remote sensing image data and limited learning richness of model features, this paper proposes a high resolution remote sensing image classification algorithm based on improved full convolution neural network. Firstly, a standardization layer is added to batch process the image, and then a pooling index is added to the image to realize the up-sampling. Finally, the pooling index, the transposed convolution and the convolution eigenvalue are combined into a feature group to restore the class pixels of the image to a great extent. It can improve the prediction ability of the model. A simulation experiment is carried out to verify the effectiveness and feasibility of the proposed algorithm.
Long-term evolution analysis of coastal geomorphology in Jiangsu based on Google Earth Engine
Authors: Yan Gu , Ruoyu Tao , lijun Yang , Tao Jin
Published: August 2021

In the past few decades, the tidal flats along the Jiangsu coast have been extensively modified, which has affected the function of a tidal flat ecosystem. In this paper, 4556 Landsat remote sensing images were processed based on the Google Earth Engine to classify features in the region from 1989 to 2019, and the overall and local geomorphology of the Jiangsu coastal area in the past three decades were analyzed and discussed. The trend of tidal flats in the study area has decreased 345.61 km2, with an average loss of 11.52 km2per year. The expansion of human activities has led to the migration of the Jiangsu coast to the sea, the reduction of natural coastline fragmentation, and the expansion of artificial coastline to the sea.
An Improved Semantic Segmentation Model for Remote Sensing Images based on HRNet
Authors: Zhou Xiaolan
Published: August 2021

Deep learning has been greatly improved recently, and natural image processing based on deep learning has also been greatly improved. However, there are still great differences between natural images and remote sensing images, among which the biggest is that the size of the target in remote sensing images is greatly different, which requires the model to have a strong multi-scale processing ability. In order to meet this goal, we use HRNet with full multi-scale fusion capability to replace ResNet to process remote sensing images. HRNet fully integrates low-level detail features, middle-level structure features and high-level semantic features, which is very suitable for remote sensing images. The experimental results show that our method has been greatly improved.
Influence of Soil Secondary Nonlinearity Effect on Seismic Response of Nuclear Island Structure
Authors: Zhu Shengdong , Chen Weiyun , Wang Yanzhen , Chen Guoxing
Published: August 2021

The effect of soil-pile-structure interaction (SPSI) is becoming one of the key issues in the seismic design of the nuclear island structures built on non-bedrock sites. The 3D lumped-mass stick (LMS) model of the AP1000 nuclear island structure considering the SPSI effect is developed to represent the steel containment vessel, the containment internal structures, and the coupled shield and auxiliary buildings supported by the pile-raft foundation. To improve the calculation efficiency, the 3D model is simplified into the equivalent 2D models in the X-Z and the Y-Z planes through vector decomposition of the 3D components and their interactions. The soil nonlinear behavior is termed the soil primary nonlinearity effect and the soil secondary nonlinearity effect (SSNE). The influence of SSNE caused by the effect of SPSI on the seismic responses of the AP1000 nuclear island structure is studied using various bedrock motions. The results show that: (1) Compared with the vertical seismic responses of the nuclear island structure, the SSNE of the horizontal responses is more obvious, and is stronger for bedrock motions with intense high-frequency components; (2) The influence of SSNE on the responses of the nuclear island structure has a positive correlation with its heights and bedrock motion levels; (3) Because of the SSNE, the peak accelerations and the peak relative displacements of the nuclear island structure decreases and increases respectively; while the 5% damped spectral accelerations of the nuclear island structure decrease in the shorter periods and increase in the mid-long periods. (4) For the peak relative displacements, the shorter the predominant periods of bedrock motions are, the higher the proportion of SSNE in the nonlinear effect of SPSI is. In general, the existence of SSNE will increase the flexibility and the energy consumption of the SPSI system of the nuclear island structure, and thus it is inappropriate to overlook SSNE arbitrarily.
Lightning monitoring method based on distributed traveling wave and lightning location system
Authors: Liu Yushun , Zhu Taiyun , Xia Lingzhi , Wang Taiping , Zhang Zhaoyuan , Li Yan , Xu Qiang
Published: August 2021

In order to improve the accuracy of lightning strike fault location and identification based on the distributed traveling wave monitoring system and lightning location system, the location algorithm and recognition algorithm are improved and integrated. The distributed traveling wave monitoring device is regarded as the lightning detection sub-station, and the calculation results of the lightning location system are corrected to get the accurate lightning flashover tower position. The lightning flashover voltage of the positioning tower is calculated based on the lightning current amplitude and the procedure method. After the lightning fault type is predetermined, the recognition calculation based on waveform feature extraction can be carried out. The actual lightning tripping fault and waveform were used to verify, the results show that the proposed method can effectively improve the accuracy of lightning strike fault location and identification.
Geographic visualization and spatial analysis of COVID-19 based on GIS
Authors: Wang Yu
Published: August 2021

By using the spatial analysis function of ArcGIS and the statistical function of EXCEL, the cumulative confirmed cases, cumulative cured cases and cumulative death cases of new-type corona pneumonia from January 2020 to July 2020 were correlated with the vector map of China’s administrative region to obtain the spatial distribution of new-type corona pneumonia nationwide. The cumulative diagnosis, cure and death tolls of the new type of coronary pneumonia were represented by color classification, and the situation of the new type of coronary pneumonia nationwide was visualized. The analysis showed that the distribution of the new type of coronary pneumonia at this stage was clustered, mainly centered in Hubei Province, spreading to the surrounding Hunan Province, Henan Province, Jiangxi Province and Anhui Province, and the sudden occurrence of the new type of coronary pneumonia occurred in very few regions.
Guoduaresearch on Key Technologies of heterogeneous network in power communication system
Authors: Chen Baoren , Hong Danke , Wang Li , Ou Yongtong , Zhong Xinhui
Published: August 2021

The development of smart grid needs the blessing of power Internet of things technology. With the continuous promotion and construction of domestic power Internet of things technology, a large number of Internet of things terminals will be connected to the network communication through different wireless communication technologies, which will form a huge heterogeneous network. Among them, wireless communication technology is the key to realize the power Internet of things. In order to give full play to the absolute advantage of the power Internet of things, this paper analyzes the characteristics and composition of the current heterogeneous network, analyzes the key points of the heterogeneous network technology, and analyzes the corresponding strategies and feelings.
Research on life cycle deformation monitoring system of Airport
Authors: Zhang Yonghao , Guo Lei
Published: August 2021

In order to meet the rapid development and strategic needs of the national economy, a large number of airports are newly built, rebuilt and expanded every year in China. With the accelerating process of urbanization, the airport construction environment is getting worse and worse: the terrain is complex, the construction process is often accompanied by high excavation and deep filling of earthwork, and the high filling airport is often accompanied by the problems of foundation settlement and slope safety and stability. Therefore, it is very important to identify and monitor the existing or potential deformation of the airport and the deformation under the external environment such as earthquake.
Numerical Simulation Research Based on Plasma Line-Tied Instability
Authors: Wang Xudan , Ding Junling
Published: August 2021

In order to study the linear instability and turbulence of the boundary plasma, this paper uses the BOUT++ numerical simulation tool. Mainly analyze the driving mechanism of the instability of the ideal balloon model, and the instability suppression mechanism of the ion diamagnetic effect, and compare with the analysis results of the dispersion relationship. Subsequently, the integral dispersion relationship is used to analyze the suppression mechanism of the shear flow. In addition, the dispersion relationship is not suitable for analyzing the global effect of the shear flow. Due to the locality of the dispersion relationship, the integral dispersion relationship uses the numerical integration of the mode structure to resolve the dispersion relationship. Used to analyze shear flow. Then, use the numerical integration of kinetic energy in the whole space to study the contribution of these effects to free energy. Finally, using the above linear analysis method, the physical mechanism of these effects under the EAST divertor configuration is studied.
Design of aircraft flight performance analysis and simulation software
Authors: Zhonghua You , Haitao Nie
Published: August 2021

Considering design of flight control system in the early stage of aircraft design is the development trend of aircraft design, which improves the design quality and reduces the cost, and the analysis of aircraft dynamic characteristics is its foundation. The aircraft flight performance analysis and simulation software is designed and developed by C++ language according to the flight dynamics principle of fixed-wing aircraft with conventional layout, combined with control law and simulation algorithm, which can be used to analyze the stability of aircraft, estimate the flight performance, preliminarily design the flight control system and carry out real-time flight simulation. The numerical example shows that the software can accurately analyze and calculate the flight performance of the aircraft, and achieve good attitude maintenance and maneuver control in the simulation. The comparison of results verifies the accuracy of the software.
Typical Feature Extraction in Alpine Lake Area of Northern Tibet Based on Gaofen-1 Satellite
Authors: Lina Dong , Kun Shang , Yun He , Xiongwei Zheng
Published: August 2021

Satellite remote sensing is one of the indispensable means of natural resources monitoring and management. With the great improvement of the spatial resolution, spectral resolution, temporal resolution and data coverage capability of Chinese satellites, domestic satellites have been deeply and extensively applied in the natural resource management and geological survey. In recent years, the impact of global change on the ecological environment and biodiversity in the alpine region of northern Tibet has aroused great concern, among which the response to land degradation, desertification and plateau wetland protection are the important contents. In this paper, Gaofen-1 (hereinafter referred to as "GF-1") satellite data are used to conduct the research and experiment of wetland and saline-alkali land feature extraction, which provides guiding suggestions and scientific references for the wider and deeper application of domestic satellites in feature extraction.
Research on Design Collaboration of Aircraft Digital Mock up for Suppliers
Authors: Xu Jian , Su Hao , Zhang Hong
Published: August 2021

Supplier design collaboration based on digital mock up is an important feature of the globalization and digitization of modern aircraft development. Supplier design collaboration based on digital mock up can organize all design engineers in different locations and time around the world, make them working in a unified design environment. It can overcome the shortcomings of traditional aircraft development, and improve the efficiency of aircraft development and shorten the development time greatly. This article introduces the advantages of supplier design collaboration based on digital mock up, focuses on the classification, general requirements, process and data management of supplier design collaboration based on digital mock up. It provides relevant reference and help for supplier design collaboration of digital mock up.
Research on Dynamic Obstacle Avoidance Path Planning Strategy of AGV
Authors: Miao Zhenteng , Zhang Xiaolei , Huang Guojue
Published: August 2021

As a highly intelligent robot, AGV has many applications in automatic production, AGV needs to ensure its own safety when it works in a complex environment. If there are irregularly moving obstacles within the working range of AGV, collision accidents are easy to occur. This paper establish a obstacle avoidance fuzzy controller based on fuzzy control algorithm, this controller can obtain the operation data of obstacle avoidance, AGV adaptive neuro-fuzzy network system is further established to train these operation data for a certain number of times, so that this system can provide correct behavior decision for AGV dynamic obstacle avoidance. This paper builds a simulation environment to test this system. It is proved that this system has good robustness and reliability.
Design of Terminal Sliding Mode Controller Based on Nonlinear Dynamic Inversion
Authors: Hu Cheng , Bai Xibin , Zhang Shifeng
Published: August 2021

In this paper, the extended state observer was applied to satisfy the high accuracy demand of the nonlinear dynamic inversion through compensating the uncertainty and disturbance of the nonlinear dynamic system as a total disturbance. The terminal sliding mode controller was adopted to assure the system converging fast and accurately. The effectivity and quickly converging of the proposal method was demonstrated by the simulation of the attitude control problem of the upper stage, with the comparison of other methods.
Anomaly Detection Method for Spacecraft System Based on High Dimensional Space Mapping
Authors: Zhang Xiangyan , Li Zhiqiang
Published: August 2021

Spacecraft system, as a typical complex system, is also a high-risk field. Even small faults in local links may bring huge losses or disasters. Analyzing the system level associated anomaly detection method caused by the interaction of multiple telemetry parameters can provide technical means for the rapid and accurate detection of system level in orbit associated faults. In this paper, firstly, a system anomaly detection method based on high-dimensional space mapping is proposed. Secondly, based on the preprocessing of telemetry data, the division of telemetry subsystem is realized. Thirdly, Based on the dimension reduction of subsystem space, the system anomaly detection method is given, and the technical process of the method is given. Finally, through the verification of on orbit actual data, it shows that the system anomaly detection result is accurate.
Analysis of CAN bus encryption and decryption performance of different chips
Authors: Zhang Yanan , Liu Tianyu , Chong Tonghong , Jia Xianfeng , Wu Zhi
Published: August 2021

In the rapid development of intelligent network connected vehicle, many information security risks have been exposed. The application of CAN bus encryption and decryption technology can solve the problem of safety communication in vehicle intranet. The sender and the receiver use the same set of key. The sender encrypts the data before sending it, and the receiver decrypts the data before applying it. In order to study the influence of CAN bus encryption and decryption on transmission efficiency, taking tc299, s32k144, mpc5606b and spc560b54 chips as examples, different encryption and decryption algorithms are used to encrypt and decrypt data of different lengths. The research shows that the time of symmetric encryption is much less than that of asymmetric encryption; With the increase of the length of the data to be encrypted and decrypted, the time required for encryption and decryption also increases; There is no significant difference in encryption and decryption efficiency between different chips. The time consumed by encryption and decryption is us level, which will not affect the real-time performance of the bus.
Effect of Polyvinyl Fiber-Steel Slag Powder on Mechanical Properties of High Toughness Cement-Based Composites
Authors: Feng Chao , Lv Hui , Xiao Chong
Published: August 2021

Steel slag micro powder is steel slag after special process grinding, is a by-product in the process of steel production. This paper studied the basic mechanical properties and crack control ability through the compression strength test (0,8%, 14%, 20%) by compressive strength test and four-point bending test of thin plate. The results show that the inclusion of steel slag has a negative effect on the compressive strength of high toughness cement base composite and not against folding strength. When the steel slag powder reaches 20%, the test matrix can still show large toughness characteristics and crack control capacity.
Effect of Sm-doped Ni-Al layered double hydroxide on electrochemical performance for supercapacitors
Authors: Shen Sijing , Guo Weimin , Zhuang Wei , Yang WenJuan , Qin Liping , Liu Xinmei , Yue Zhiwen
Published: August 2021

Sm-doped Ni-Al layered double hydroxides (LDHs) were successfully prepared via hydrothermal-assisted coprecipitation method. The structure and surface morphology of the samples were characterized by X-ray diffractometer (XRD), Fourier transform infrared spectrometer (FT-IR) and scanning electron microscope (SEM). The electrochemical performance of the samples as prepared was measured by cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) and electrochemical impedance spectroscopy (EIS). These results show that Sm-doped Ni-Al LDH exhibit higher specific capacitance 2177 F⋅g-1 at a current density of 1 A⋅g-1, compared with pure Ni-Al LDH with a specific capacitance 1312 F⋅g-1 at same current density.
Preparation and properties of hydrotalcite inorganic filler/polylactic acid composites
Authors: Liu Hongbo , Huang Zhiyong , Chen Xiuzhu , Zhong Junwen , Wang Ying , He Xiaohong , Liu Xuewu
Published: August 2021

Hydrotalcite inorganic fillers with different metal ratios were synthesized by coprecipitation method and hydrothermal method. The hydrotalcite inorganic fillers/polylactic acid composites (HT/PLA) were prepared by melt blending method. The mechanical properties, flame retardancy and thermal properties of the composites were investigated. The results show that HT inorganic filler was successfully prepared by coprecipitation method and it had typical HT structure. Compared with pure PLA, the impact strength and bending strength of HT/PLA composites decreased. The tensile strength, elongation at break, bending strength and tensile modulus of elasticity of the self-made M-Mg/Al-HT/PLA composite were better than those of the purchased C-Mg/Al-HT/PLA composite. The oxygen index of HT/PLA composites increased obviously, and the oxygen index of HT/PLA composites increased with the increase of the amount of HT. Different kinds of HT/PLA composites have different flame retardancy, and the order is Cu/Mg/Al-HT/PLA>Co/Mg/Al-HT/PLA>Ni/Mg/Al-HT/PLA>Mg/AlHT/PLA>Zn/Mg/Al-HT/PLA. The plasticity of HT/PLA composite is higher than that of pure PLA, and its thermal stability is better.
Effects of organic carbon source on the performance and bacterial structure in biofilm processes for source water pretreatment
Authors: Liu Ya-lei , Tu Bin , Yang Guang-feng , Zhao Yi-chun , Li Yi-shu , Fang Yuan-yuan , Song De-dong , Mu Jun , Sun Jing-ya , Zhu Liang , Xu Xiang-yang
Published: August 2021

The operation performance of biofilm system is limited by the oligotrophic quality of source water, especially the bioavailable organics. In this study, two lab-scale biofilm reactors (R1 and R2) feeding different organic carbon sources (OCS) were built up using sediment in drinking water source as bacterial source. Experimental results showed that sediment in biofilm systems enhanced the NH4
+-N removal performance. Using ethanol as OCS was more beneficial to the removal of NH4
+-N with ammonia removal efficiency (ARE) of 87.0 ± 5.4%, which was higher and more stable than that of glucose with ARE of 83.9 ± 13.3%. Organic carbon source changed the bacterial structure in biofilm systems. The dominant phyla in biofilm under ethanol condition were Proteobacteria, Bacteroidetes and Firmicutes with relative abundances (RA) of 29.1%, 32.7% and 22.0%, respectively. The dominant phyla in biofilm exposure to glucose was Proteobacteria with an RA of 63.4%. At genus level, Nitrospira, Lachnospiraceae, Arcobacter and Hyphomicrobium were dominant under ethanol condition (R1) with the total relative abundance of 20.5%. Sphaerotilus was the dominant genus under glucose condition (R2) with RA of 33.72%. These dominant bacteria were basically having the ability for the removal of nitrogen and organic matter.
Research on Friction and Wear Performance of Plasma Sprayed WC/Ni Coating
Authors: Sun Yang , Chen HaiFeng , Yang Jie , Xu TianQi , Jia JunHong
Published: August 2021

In this paper, atmosphere plasma spray (APS) is used to prepare WC/Ni coating on 1Cr18Ni9Ti stainless steel to enhance the wear resistance of materials of the axial-flow fan. The phase composition and microstructure of the spraying coating were analyzed, and the tribological properties of the coating were investigated through the ball-disk point contact sliding dry friction test. The results show that the spray powder is melting and spreading well by using nickel coated tungsten carbide powder as the spray powder combined with APS technology. The as-sprayed WC/Ni coating has a dense structure, slight oxidation. The hard phase tungsten carbide is evenly distributed and the interface of the bonding phase nickel is well combined with tungsten carbide. The microhardness of the coating cross-section can reach 655±90HV0.3. In the point contact wear test with high contact stress, tungsten carbide particles are pinned to the friction surface, which greatly improves the resistance to abrasive wear. The coating wear rate is only 2.42×10-6mm3⋅N-⋅m-1, and the anti-wear of the coating is about 136 times that of Inconel718 alloy under the same friction condition. The dry friction and wear mechanism of the WC/Ni coating are manifested as surface fatigue scale peeling. The large pieces of tungsten carbide particles are prevented from being pulled out and peeled because of the crushing of tungsten carbide particles and the bonding effect of nickel. And the anti-wear of the coating has not deteriorated due to fatigue during the high friction cycle.
Design and mechanical performance analysis of V-joint of new steel structure
Authors: Liu Wenting , Zhang Xiaomeng , Ren Qingying , Li Shengze
Published: August 2021

Aiming at the Beijing 2022 Winter Olympic Games, a new type of steel-wood combination sunshade structure system was proposed, and its selection was analyzed. The related joint forms were studied, and the new joint forms were put forward. The mechanical performance of the new joint was analyzed through tests and finite element simulation.
Effect of additives on the mechanical properties of bulk polymerized Acrylic using orthogonal test
Authors: Liu Di , Zhu Haitao , Ding Zhongjun , Zhang Yi
Published: August 2021

The effects of different additives on mechanical properties of acrylic were studied by orthogonal test, using methyl methacrylate as raw material, concentration of initiator(azobisisobutyronitrile), plasticizer (Dibutyl Phthalate) and release agent(Stearic Acid) as the influence factors. The results show that: among the three additives, initiator is the most significant factor, which has the greatest impact on the mechanical properties of acrylic. With increasing of initiator content, the tensile strength of acrylic decreases. The effect of plasticizer and release agent on the mechanical properties of acrylic is relatively small. As the increase of plasticizer content, the tensile strength and bending strength decline. Finally, the best ratio of the three additives is initiator=0.06, plasticizer=3.0, release agent=1.0.
The feasibility of aerobic granular sludge formation without inoculated sludge
Authors: song Tao , li Ji , Zhang Xiaolei , Shao Peibing
Published: August 2021

In this study, the feasibility of aerobic granular sludge formation without inoculated sludge was detected. After 10 days operation, AGSs were discovered in reactor and the MLSS and settling ability of AGS enhanced gradually. After 21 days operation, the effluent NH4
+-N and COD keep low than 10 and 100 mg/L, respectively. During the formation of AGS, the content of EPS gradually increased and remained stable. Microbial community showed that EPS secretion genera (such as Paracoccus, Flavobacterium and Thauera) were main genera in AGS.
Analysis of the thermal stability of a battery under overcharge and over-discharge
Authors: Wang Hongwei , Liu Jun , Gu Zhengjian , Zhu Yusong , Fu Yanling , Tao Ziqiang , Zhang Qing
Published: August 2021

The results indicate that, when a battery is over-charged, the battery’s surface temperature increases first because of ohmic heat, and after that, internal short-circuit occurs, resulting in the battery experiencing thermal runaway. However, in the case of over-discharge, the battery’s surface temperature rise is limited. Therefore, during actual use, attention needs to be paid so as to prevent a battery from over-charge.
Performance analysis of ORC low temperature waste heat power generation system
Authors: Peng Bin , Liu Shuai , Liu Huixin , Zhou Tianhao
Published: August 2021

For 90~180°C low temperature waste heat resources, three different types of organic working fluids, benzene, isopentane and R245fa are selected from the perspectives of safety, environmental protection and physical properties of working fluid. The mathematical models of the system are established through MATLAB and REFPROP and the influence of the evaporation temperature on the performance of the ORC low temperature waste heat power generation system is studied. The results show that the thermal efficiency and net output power of the system increase with the increase of evaporation temperature; the evaporation pressure of CFC-type working fluids is relatively low; the net output power and thermal efficiency of HFC and HC-type working fluids are generally relatively low. The evaporator has the largest irreversible loss in the system, followed by the condenser and expander while the working fluid pump has the smallest irreversible loss.
Study on shear stress distribution of glass fiber reinforced polymer soil nail in foundation pit support pullout test
Authors: Wang Xiang-li , Deng Chun-gang , Qin Yue , Shen Gang , Chen Chao
Published: August 2021

To solve the problem of reinforcement bolt corrosion caused by the safe stability problem in geotechnical engineering, and engineering red line in geotechnical engineering, the fiber-reinforced composite material is gradually applied to the civil engineering field, and glass fiber reinforced polymer has high strength, light quality, corrosion resistance, the advantages of easy cutting has been widely used. In this paper, the stress distribution and deformation characteristics of GFRP anchors in the process of pipe pulling are studied through the excavation tube pulling test of GFRP anchors in actual working conditions. Secondly, the performance difference between the GFRP bolt and reinforced bolt in foundation pit engineering is analyzed. The results show that the axial force of the GFRP anchor bolt decays fastest near the anchor head, and decreases with the increase of anchor depth The shear stress distribution is convex. With the increase of the drawing load, the shear stress peak will increase, and the influence range of the shear stress will also increase. With the increase of the load, the shear stress peak of the GFRP bolt and the anchor solid will shift to the position far away from the anchor head.
An Improved Method for Constructing Health Factors of Rolling Bearing
Authors: Shu Tao , Zhang Yichi , Xu Yan , Zhang Pengxiang
Published: August 2021

Aiming at the problems of low performance index and redundant information of multi-class physical health factors, a method of building rolling bearing health factors based on improved restricted Boltzmann machine is proposed. By fusing multi-class physical health factors, the virtual health factor of rolling bearings is constructed. Extracting physical health factors in time domain and frequency domain of rolling bearing vibration monitoring signals as inputs; the performance degradation mechanism model is added to the regularization term of the Restricted Boltzmann Machine, the performance degradation information contained in the input data is mined, the virtual health factor construction model of rolling bearings is built, and the model parameters are adjusted by the health factor evaluation criteria to improve the performance of the virtual health factor. The life cycle test of rolling bearings shows that compared with the principal component analysis method, the monotonicity of virtual health factors based on the improved restricted Boltzmann mechanism is increased by 147.6% and 38.5%, the trend is increased by 113.8% and 16.1%, and the robustness is increased by 60% and 8.42%, respectively.
Application of environmentally friendly amphoteric polyacrylamide hydrophobically modified with plant oil as additive in water-based drilling fluid
Authors: Lei Ming , Huang Weian , Sun Jinsheng , Shao Zixuan , Wu Tongliang , Fan Yu , Huang Haoyong
Published: August 2021

Hydrophobic associating polymers show great potential in formulation of high-performance drilling fluids, due to their hydrophobic associative ability in high-temperature and high-salt conditions. Herein, a novel amphoteric polyacrylamide of poly(acrylamide/2-acrylamido-2-methyl-1-propanesulfonic acid/methylacrylethyl trimethylammonium chloride) hydrophobically modified with epoxidized soybean oil denoted as PAADE was prepared and applied in water-based drilling fluid, and one without hydrophobic modification (PAAD) was also used for comparison. Compared with PAAD, PAADE displayed characteristic association behavior with a critical association concentration (CAC) of 0.3 w/v%, and a salt thickening phenomenon over 3 w/v% NaCl concentration. The impacts of PAADE and PAAD on rheological and filtration properties of bentonite-based drilling fluid (BTDF) were evaluated under different salinity. The fitted Herschel-Bulkley rheological parameters indicated that BTDF containing PAADE showed stronger yield stress, easier flowability and better salt resistance at a reasonable concentration below CAC. Meanwhile, PAADE largely reduced the fluid loss of BTDF before and after thermal aging at 150°C, showing high temperature tolerance. The addition of NaCl promoted larger reduction of filtration. The superior properties of PAADE in BTDF were revealed to be the competitive results of salt-induced hydrophobic association and inter-particles configuration transition. Moreover, the incorporation of epoxidized soybean oil improved the biodegradability of PAADE.
The effect of heavy metals on sulfur autotrophic short-cut denitrification
Authors: Wei Youcheng , Zhang Xiaolei , Liu Hui , Li Ji , Cheng Bohan
Published: August 2021

A batch experiment was used to investigate the influence of common heavy metals Cr(VI), NI(II), Cu(II) on sulfur autotrophic short-cut denitrification. Experimental results show that low concentrations (1-3 mg/L) of heavy metals have little effect on sulfur autotrophic shortcut denitrification, and high concentrations (4-10 mg/L) of heavy metals have obvious effects on sulfur autotrophic short-cut denitrification. Inhibition. The doserape model is used to fit the doseeffect curve of heavy metals, and the IC50 is used to judge the toxicity. The order of the IC50 of each heavy metal is: Cr(VI)>NI(II)>Cu(II). The effects of two heavy metals in the binary system of Cu(II) and NI(II) are antagonistic.
Metagenomics reveals the taxonomy and resistance mechanism of antibiotic resistance genes in bacterial communities of an aquaculture pond
Authors: Qu Jiangqi , Wu Yanfei , Liu Yi , Cui Yuxiang , Zhao Meng , Zhu Hua , Zhang Qingjing
Published: August 2021

In order to reveal the distribution characteristics of antibiotic resistance genes (ARGs) in freshwater aquaculture ponds, the microbial composition and antibiotic resistance gene types in the aquaculture environment were analyzed by using high-throughput and metagenomics sequencing technology. Our results showed that there were significant differences in the dominant bacteria composition in the water and sediment of aquaculture ponds. The dominant phylum in aquaculture water was Actinobacteria, Proteobacteria, Cyanobacteria and Bacteroidetes, while the phylum Actinobacteria, Chloroflexi and Proteobacteria were enriched in sediment. Compared with the comprehensive antibiotic research database (CARD), a total of 187 ARGs were identified, which were mainly multidrug, MLS and Tetracycline antibiotic resistance genes. There were 5 resistance mechanisms in the aquaculture environment, of which antibiotic efflux was the main resistance mechanism. Correlation analysis between ARGs and microbes showed that the abundance of Bacteroidetes, Cyanobacteria and Chloroflexi significantly affected the abundance of major resistance genes. This study is of great significance to protect the micro-environment of aquaculture ponds and control the pollution and spread of ARGs.
Research Progress on degradation of Organic pollutants in Water Body by Iron-based Materials activated persulfate
Authors: Dong Lei , Pan Xiong , Zhang Sheng , Lin Li , Yin Guochuan
Published: August 2021

The advanced persulfate oxidation technology has shown great potential in the efficient degradation of organic pollutants in water body, owing to its strong oxidation ability, easy operation and many other advantages. At present, the development of this technology focuses on the choice of activation mode of persulfate, and its essence lies in the cleavage of O-O bond in persulfate. Iron-based catalysts have been widely used in persulfate activation because of their advantages such as earth abundance, eco-friendliness and cost-effectiveness. In this paper, the methods and research progress of activating persulfate by iron-based materials (including nanometer zero-valent iron, common zero-valent iron, nanometer iron tetroxide) are reviewed. Finally, the existing problems and development direction of persulfate advanced oxidation technology in the current application are analyzed, in order to promote the development of related research work.
Characteristics analysis of sugar beet powder fermentated by staphylococcus xylostose
Authors: Yu Hao , Haibin Li , Siyu Shi , Ting Li , Jiayun Kang , Wenhui Liang , Meixia Pang , Fang Wang , Jinghua Qi
Published: August 2021

As a color and antiseptic additive, nitrite has been widely added to meat products. The large amount of nitrite remaining in meat products will generate carcinogenic nitrosamines in the body after eating, so natural sources of nitrate-rich fermented vegetables Powder has certain potential as a substitute for nitrite. In this paper, fermented beet powder rich in nitrite as the research object, spectral characteristics were analyzed. The stability of its pigments under the conditions of temperature, time, pH, metal ions, oxidants and preservatives were studied. The results showed that the maximum absorption wavelength of fermented beet powder measured with an ultraviolet spectrophotometer was 538 nm. The conditions that most affect the content of betacyanins were temperature, pH, and metal ions.
Quality Control of Polyacrylamide Products with Infrared Spectroscopy
Authors: Peng Yunyan , Rong Yan , Feng Shichun , Jin Dong
Published: August 2021

The anionic, cationic and nonionic polyacrylamide samples, as well as four kinds of inorganic salt samples, including sodium sulfate, sodium chloride, sodium carbonate and ammonium sulfate, were respectively analyzed with Fourier transform infrared spectroscopy (FT-IR) to establish their standard reference infrared spectra, meanwhile the characteristic peaks are distinguished. At the same time, the polyacrylamide samples containing different concentration and different kinds of inorganic salts were respectively analyzed with FT-IR to establish their IR spectra. Then a method used for quality control of polyacrylamide products was established, which can be used to evaluate the purity of the products, determine the impurities and relevant contents preliminarily.
The effect of Strontium contents on novel MIEC1-MIEC2 dual-phase ceramic-based oxygen transport membranes
Authors: Bai Wei , Feng Junxiao , Luo Chunhuan , Han Jingxiao , Wang Hailiang
Published: August 2021

Although ceramic-based oxygen transport membranes (OTMs) have irreplaceable advantages over traditional oxygen production technologies, their oxygen permeability and stability need to be further improved. Based on the theoretical starting point of increasing the three-boundary reaction zone and reducing blocking effect, a set of new dual-phase membranes 75wt%Ce0.8Sm0.1Cu0.1O2-δ-25wt%-Sm0.8Sr0.2Co0.8Fe0.2O3-δ (CSC-8282) and 75wt%Ce0.8Sm0.1Cu0.1O2-δ-25wt%Sm0.3Sr0.7Co0.8Fe0.2O3-δ (CSC-3782) with different strontium contents were prepared by a one-pot sol-gel method ensuring that each element has the same chemical potential. The surface morphology, crystal structure and element distribution are systematically studied by SEM, XRD and EDS, which confirms that the synthesized membranes have an obvious dual-phase structure and excellent compactness. The results of the oxygen permeability experiment show that the oxygen permeability of CSC-3782 is always higher than that of CSC-8282 under any conditions due to the inducing effect of strontium on oxygen vacancies, and flow rate of CSC-3782 at 960°C reached 0.64 and 0.22mL⋅cm-2⋅min-1 for He and CO2 as a sweep gas, respectively. The final long-term stability test confirmed that the dual-phase composite membrane with great prospects for development has high temperature stability and CO2-tolerant property, and the doping of strontium to A-site of perovskite contributes to the improvement of its performance.
PFC Numerical Simulation Study of Thermal-mechanical Coupling of Sandstone under Unidirectional Heating
Authors: Xin Lin , An Mingyu , Feng Mingze , Cheng Weimin , Li Kaixuan , Wu Jing , Li Jiaze
Published: August 2021

In order to study the rock thermal cracking law of the roof rock in the combustion zone of underground coal gasification under the special condition of unidirectional heating, the PFC particle flow software was used to carry out the numerical simulation of thermal-mechanical coupling. The uniaxial compression experiment was used to complete the PFC parameter calibration, establish a mechanical model, and compare the results of the unidirectional heating test with the simulation results. It was found that the relationship between the temperature at the measuring point, the thermal stress and the heating time of the two is very similar. It shows that the simulation results are highly accurate. The simulation results are as follows: when the model is at 450°C and 600°C, larger-scale cracks are formed and the second larger-scale crack evolution occurs; acoustic emission simulation can be divided into three stages: the first peak stage, the energy accumulation stage, and the second stage. In the second peak stage; the number of model cracks increases with the increase in temperature, and the shear cracks are the main ones, indicating that the model will expand laterally after being subjected to thermal stress, mainly occurring shear failure.
Research on the drop strength of coal powder in hot air dense medium fluidized bed
Authors: Li Lingyue
Published: August 2021

In this paper, the drop strength of pulverized coal in a hot air dense medium fluidized bed was studied, and the influence of factors such as coal surface moisture, drying temperature, drying time, air volume and other factors on the drop strength were investigated, and the mathematical correlation of the drop strength was established; it shows that with the increase of drying time, the fall intensity of coal decreases; as the drying temperature rises, the fall intensity decreases; as the surface moisture of coal increases, the coal fall intensity decreases; as the air volume increases, the coal fall intensity decreases.