bluuebunny/crossref_metadata_2025_split huggingface dataset:
Research on trajectory tracking of unmanned vehicle based on model predictive control
Authors: Liu Zheng , Kang Haiyang 
Published: April 2021

Abstract
Trajectory tracking control is a key technology in the research and development of autonomous vehicles. In view of the fact that the traditional model predictive control (MPC) method does not consider the interaction of longitudinal and lateral forces in the trajectory tracking control of unmanned vehicle, a vehicle trajectory tracking control method based on model prediction is proposed. Considering the longitudinal and lateral coupling of tire force, a more accurate tire force model and dynamic model are obtained. Besides a variety of constraints such as control quantity, control increment and output are added. The co-simulation platform CarSim / Matlab / Simulink is used to verify the designed controller by taking the four-wheel front steering vehicle. The results show that the track tracking process is stable and reliable under the condition of double lane change and the tracking effect of vehicle to reference track is very ideal.
Design and Application of Automatic Dust-free Convey Equipment for Heavy Medium Solid Material on Offshore Drilling Platform
Authors: Xiaolong Lian , Hongli Liu , Bo Zhou , lin Hou 
Published: April 2021

Abstract
The Yingqiong Basin, a large high-temperature and high-pressure gas field in the South China Sea, is one of the three high-temperature and high-pressure areas in the world. According to incomplete statistics, from 1984 to 2013, a total of 30 high-temperature and high-pressure exploration Wells were drilled in the South China Sea. According to the drilling situation, there were 4 ultra-high temperature and high-pressure Wells with temperatures over 200°C and mud gravity over 2.20sg. With the increasing demand for oil and gas in China, the drilling operations of HP/HT Wells are also increasing, which is the inevitable trend of the development of oil and gas drilling technology. Due to the high pressure of Wells, drilling fluid need to be weighted by additives during cementing operations. In the past, these operations on offshore platforms were all done by manual. Therefore, we developed a set of positive-negative pressure conversion type continuous conveying device which integrated a weight medium negative pressure cutting device. The device consists of negative pressure dust-free feeding system, negative pressure conveying system, positive and negative pressure continuous conveying system, dust removal system and automatic control and detection system. It can realize flexible pipeline transmission through negative pressure and positive pressure. The device contains a variety of detectors to detect the operation situation in real time, and the control system can realize the functions of automatic control and automatic fault alarm. The results of experiment and field application show that the device can meet the high demand of heavy medium transportation.
Aerodynamic effects on an emulated hovering passerine with different wing-folding amplitudes
Authors: Chen Wei-Han , Yeh Szu-I 
Published: April 2021

Abstract
Bird flight involves complicated wing kinematics, especially during hovering flight. The detailed aerodynamic effects of wings with higher degrees of freedom (DOFs) remain to be further investigated. Therefore, we designed a novel multiarticulate flapping-wing robot with five DOFs on each wing. Using this robot we aimed to investigate the more complicated wing kinematics of birds, which are usually difficult to test and analyze. In this study the robot was programmed to mimic the previously observed hovering motion of passerines, and force measurements and particle image velocimetry experiments. We experimented with two different wing-folding amplitudes: one with a larger folding amplitude, similar to that of real passerines, and one with only half the amplitude. The robot kinematics were verified utilizing direct linear transformation, which confirmed that the wing trajectories had an acceptable correlation with the desired motion. According to the lift force measurements, four phases of the wingbeat cycle were characterized and elaborated through camera images and flow visualization. We found that the reduction in folding amplitude caused a higher negative force during upstrokes and also induced a greater positive force at the initial downstroke through ‘wake capture’. This could increase the vertical oscillation while hovering despite a minor increase in average force production. This phenomenon was not observed during forward flight in previous studies. Our results provide a critical understanding of the effect of wing folding which is required for designing the wing kinematics of future advanced flapping-wing micro aerial vehicles.
An emerging impact of Eurasian spring snow cover on summer rainfall in Eastern China
Authors: Zhang Taotao , Wang Tao , Feng Yingying , Li Xichen , Krinner Gerhard 
Published: April 2021

Abstract
Eurasian spring snow cover is widely considered as an important predictor of Asian summer monsoon rainfall, but its possible role in the formation of the north–south dipole structure of rainfall anomalies (NSDR)—a major mode of the eastern China summer rainfall variability—remains elusive. Here, we show that, there is a close connection between the western Eurasian spring snow cover (WESS) and NSDR during our research period 1967–2018, with less WESS tends to be accompanied by a wetter south-drier north pattern over eastern China, and vice versa. However, this relationship was not significant before the late 1990s, but has since become significant. Further analyses demonstrate that the shift in the WESS–NSDR relationship could be attributed to the modulation of summer North Atlantic Oscillation (SNAO). After the late 1990s, the WESS-related anomalous atmospheric circulations during summer are largely reinforced by the constructive superposition of those with same signs induced by SNAO, which in turn would intensify the impact of WESS and hence lead to a strong WESS–NSDR connection. In contrast, the influences of WESS are counteracted by those with opposite signs associated with SNAO before the late 1990s and thereby result in a weak snow–rainfall relationship. Our findings, along with the decline in Eurasian spring snow cover, provide a potential explanation for the recent ‘South Flood–North Drought’ pattern observed over eastern China.
Review of 3D digital core reconstruction methods for deep shale gas reservoir
Authors: Liu Yuejiao , Lai Fuqiang , Kou Xiaopan , Wang Yifei , Wang Haitao , Zhao Xiaotian , Tan Zhoujie 
Published: April 2021

Abstract
Conventional digital core reconstruction methods are not suitable for deep shale gas reservoirs with low porosity and permeability, anisotropy and complex mineral composition, and conventional single resolution three-dimensional digital core structure model cannot fully describe the core structure of shale gas reservoirs of different scales. In this paper, the advantages and disadvantages of different digital core reconstruction methods are summarized by analyzing examples. It is found that MCMC core reconstruction method is more suitable for image reconstruction of 3D digital structure model core of deep shale gas reservoir in China; Finally, in view of the problems existing in conventional digital core reconstruction methods, combining CT imaging with ion beam focused electron microscopy (FIB-SEM) imaging technology, a 3D digital core structure model with multi-scale, multi-component and corresponding macro pore and micro pore of the corresponding reservoir is proposed. The micro spatial distribution structure of the model is similar to that of real shale gas reservoir core, it overcomes the difficulty that the resolution of single scale 3D digital gas reservoir core model and the micro size characteristics of gas reservoir core cannot be perfectly considered. It can not only accurately describe the micro pore space distribution structure of real core gas reservoir, but also accurately describe the macro heterogeneity of deep shale gas reservoir core.
Countermeasures for the Development of International Economy and Trade under the Environment of E-commerce
Authors: Wu Guanghua 
Published: April 2021

Abstract
The development of computer science promotes the popularization of information technology and Internet. China’s e-commerce has made further development and ushered in a period of rapid development. International trade based on e-commerce ushers in new opportunities and challenges. Therefore, it is of great significance to put forward the corresponding countermeasures for the development of international economy and trade under the environment of e-commerce. Based on this, this paper analyzes the problems existing in the international economic trade under the e-commerce environment, and puts forward the development strategies.
Research on Prevention and Control Measures of Agricultural Non-point Source Pollution of Plateau Lakes in Yunnan Province
Authors: Tang Jinli , Duan Yanzhi 
Published: April 2021

Abstract
The situation of agricultural non-point source pollution in Yunnan Province is dire, and its main feature is that non-point source pollution leads to lake eutrophication of nitrogen and phosphorus. Because of the current situation of the nine plateau lakes in Yunnan Province and the prevention and control of agricultural non-point source pollution in the river basin, by analyzing the characteristics of regional non-point source pollution and learning from advanced experience at home and abroad, a scientific approach to the prevention and control of the agricultural non-point source of plateau lakes in Yunnan Province is initially proposed.
Exploration on Fracturing Technology of Oil Production Well in Transitional Zone
Authors: Duan Yajie 
Published: April 2021

Abstract
There are low permeability and poor crude oil physical property in the second-class oil layer of the eastern transitional zone, especially crude oil viscosity is high, and underground crude oil viscosity reaches 14mPa.s. After the weak-alkali ASP combination flooding was carried out, the liquid production dropped sharply in some oil production wells, during the initial effective stage of the oil production wells, by combining the analysis of fine geological research results and the dynamic and static reflection of oil production wells, fracturing transformation was implemented for oil production wells, and good oil increase and water decrease effect was achieved.
Risk Evaluation and Simulation Analysis of Occupational Diseases in Coal Mine Workers
Authors: Liu Qing , Cao Qinggui , Qiu Xiaoxuan , Yunna Wang 
Published: April 2021

Abstract
In order to solve the problem of inaccuracy in the evaluation of occupational disease risk due to the characteristics of unknown and uncertainty, the coal mine occupational disease evaluation system was constructed, the weighting method of “AHP+entropy method” was introduced, and the Lagrangian function and European style were used. The distance function is used to obtain the combined weights of occupational disease evaluation indicators, and the unascertained measurement theory is used to construct the occupational disease risk evaluation model. After that, the Arena software is used for simulation analysis, and the continuous space iteration method is used to obtain the priority of coal mine occupational disease influencing factors. A case study on the occupational disease risk of Zhenchengdi Coal Mine is carried out with the method proposed in this paper. The simulation results and evaluation results are consistent with engineering examples, which shows that the evaluation model based on the “AHP+entropy weight method” unascertained measurement theory is practical and accurate. It is feasible and reliable, also can provide a basis for the risk assessment and prevention of coal mine occupational diseases.
Investigation and Analysis of the Main Pollution Sources in Fuxian Lake
Authors: Cheng Haoliang , Yang Jurui , Liu Yuxin , Yuan Huihao 
Published: April 2021

Abstract
Fuxian Lake is a plateau-based freshwater lake. In recent ten years, with the rapid development of the economy around the lake, the water quality of Fuxian Lake has declined and the nutritional status in lake has increased obviously. To identify the main sources of pollution in Fuxian lake and provide a reference for the protection and management direction and theoretical guidance, the pollution status of Fuxian Lake basin was analyzed and evaluated from the aspects of rural domestic pollution, farmland runoff pollution, urban domestic pollution, phosphorous chemical pollution and tourism pollution, respectively, based on years of field investigation and the indexes detection and analysis such as chemical oxygen demand (COD), total nitrogen, total phosphorus. The results showed that the pollution in Fuxian Lake basin mainly came from the rural non-point source pollution, urban domestic pollution, waste phosphate rock area pollution, tourism pollution and other aspects, among which the most important source of pollution was the rural non-point source pollution, including watershed village pollution, human and animal excrement pollution, rural waste pollution, and farmland runoff pollution in the basin. The COD, total nitrogen and total phosphorus from rural non-point source pollution accounted for 94.81%, 94.85% and 87.79% of the total pollution into the lake, respectively. Among them, the farmland runoff pollution was the most important component of rural non-point source pollution
Carbon Information Disclosure in The Network Environment
Authors: Wu Die , Zhu Shuzhen 
Published: April 2021

Abstract
Facing global warming and environmental problems, enterprises should fulfill their environmental responsibilities in protecting the environment, reducing carbon emissions and improving environmental quality. With the development of computer network technology and the promotion of 5G technology, carbon information disclosure has become intuitive and individualized, which will, to a great extent, help enterprises disclose carbon information in a timelier manner. Based on the current situation of carbon information disclosure in the network environment, this paper studies and analyzes the problems with regard to carbon information disclosure in the network environment, so as to better satisfy the diversified demands of carbon information users in the network environment and provide assistance for decision makers.
Research on the Development Quality Evaluation of energy enterprises from the perspective of low-carbon
Authors: Xie Libin , Fang Yanyun 
Published: April 2021

Abstract
National strategic transformation puts forward higher requirements for energy conservation and emission reduction in energy enterprises. Under the low-carbon perspective, energy enterprises should seize the opportunity and combine their own conditions to realize energy conservation and emission reduction while ensuring the development quality of enterprises. This paper constructs a development quality evaluation system for energy enterprises, which includes four first-level indicators including customer dimension, environmental protection dimension, social responsibility dimension and financial dimension, and 18 second-level indicators, providing reliable basis for high-quality development of energy enterprises.
Inheritance and dissemination of Chinese Wushu from the perspective of cultural geography
Authors: Guo Qingkai 
Published: April 2021

Abstract
In the process of its formation and development, Wushu is deeply influenced by the cultural and geographical environment. At present, the inheritance and development of Wushu have been paid more and more attention. The international spread of Wushu has become a window for the world to understand Chinese culture. Therefore, it is of great significance to study Wushu culture from the perspective of geographical culture. From the perspective of cultural geography, the emergence and development of Wushu is one of the hot spots in the study of Wushu culture. Based on this perspective, this paper discusses the inheritance and dissemination of Chinese Wushu, with a view to contributing to the spread of Chinese Wushu.
Effect of Er content on the interfacial microstructure, shear properties and creep properties of Sn58Bi joints
Authors: Li Qi , Xiong Min , Liu Fengmei , Wu Huacheng , Yue Xiong , Li Likun , Gao Haitao , Yi Yaoyong 
Published: April 2021

Abstract
The influences of Er content on the interfacial microstructure shear properties and creep properties of Sn58Bi joints were investigated in this study. The intermetallic compound composition of Sn58Bi-xEr/Cu was Cu6Sn5 compound. The addition of Er suppressed the activity of Sn element, decreased the driving force for the growth of Cu6Sn5 intermetallic compound and decreased the thickness of Cu6Sn5 intermetallic compound layer. The shear properties and creep durability of Sn58Bi-xEr/Cu welded joints were improved to a certain extent. At the Er content of 0.1%, the shear strength and creep durability properties of the solder alloy are relatively optimal. When wt%Er was more than 0.1%, with the increasing Er content of rare earth elements, the internal organization of the joint interface is coarsened, and the flatness of the IMC layer at the interface is reduced, which leads to the decrease of the creep performance of the final joint.
The Effect of The Precision of Exercise Data on Food Selection
Authors: Luo Yuanfang , Yuan Dan 
Published: April 2021

Abstract
Replacing calorie information with the exercise data has been a new direction for public policies on food marketing and an alternative for food enterprises. Behavioral studies on the effect of data precision on food selection in real-life scenarios indicate that more precise exercise data will make consumers to select healthy food with lower calories. These findings shed light on the managerial application for policymakers and food enterprises.
Single Molecule Force Spectroscopy of Siloxanes
Authors: Chen Ling , Yang Liya , Wang Chunxia , Zhu Ting 
Published: April 2021

Abstract
Silicone elastomers are high tech materials with some disadvantages. In order to make some improvements, the measurement and analysis of force-extension curves with Single molecule force spectroscopy (SMFS) is necessary. To determine the elastic properties of the silicone elastomers, modifications on the cantilevers and on the wafer surfaces have been performed.
Study on Separation and Purification of Chemical Components of Dichloromethane from Pine Needle Extract
Authors: Liu Yinan , Liao Bing , Guo Wenjie , Fu Yujie , Sun Wan , Fu Yao , Wang Dandan , Kang Hongling 
Published: April 2021

Abstract
To study the chemical composition of the extract of cedar pine needle methylene chloride. Methods: The paper used silica gel and Sephadex LH-20 column chromatography to separate and purify, and carried out structural identification based on physical and chemical properties and spectral data. At the same time, gallic acid was preliminarily separated by high-performance liquid chromatography (HPLC), the separation conditions of gallic acid were determined, and the content change of gallic acid after tannin was acid-decomposed was determined, proving that the extract may contain decomposable hydrolysis Tannin or compound tannin. Results: Five compounds were isolated from the dichloromethane extract of cedar pine needles, which were identified as: ferulic acid (1), osthol (2), β-phenylacrylic acid (3), paeonol (4), Magnolol (5). Conclusion: All compounds except Compound 5 were isolated from this plant for the first time.
Research on Improvement Technology of Wet Grinding Process Based on L-Cysteine Fermentation Condition
Authors: Yan Rong , Li Xin , Liu Yinan 
Published: April 2021

Abstract
To study the effects of wet milling, farm Corn; starch; gel filtration chromatography; wet milling; fermentation modification; extrusion enation modification of lactic acid bacteria and extrusion technology on the composition of starch in corn flour. Common corn varieties as a material, corn flour is prepared by wet milling, fermentation modification of lactic acid bacteria and extrusion puffing technology, and starch is extracted from corn flour, using Sepharose CL-2B, Agarose gel column chromatography was used to study the composition of starch. The GPC chart of wet-milled corn flour starch has a bimodal distribution, and the starch molecules are divided into macromolecules Branched-chain region (region I) and straight-branched mixed region (region II), the elution volume of region I is 21-42 ml, and the average molecular weight polymerization degree is 26 632-18 666,The elution volume of zone II is 42-70 ml, and the relative molecular weight average polymerization degree is 18 666-8 046; the starch GPC spectrum of fermented modified corn flour is also double peak Distribution, but the average molecular degree of polymerization of the two regions narrowed, and the starch composition changed; the GPC spectrum of extruded corn flour starch showed a single peak distribution, and the relative The average polymerization degree of the molecular weight is 27 960-9 374. [Conclusion] Starch molecules are degraded during fermentation and extrusion of lactic acid bacteria, and degradation occurs during fermentation The starch molecules are mainly the starch molecules between zone I and zone II, and the high temperature and high shear in the extrusion process make most of the starch molecules in zone I occur degradation.
Study on Preparation and Luminescence Properties of Li2CaSiO4: Pr3+ Phosphor
Authors: Li Zhisen , Wen Yan , Chen Dai , Man Shiqing 
Published: April 2021

Abstract
In this paper, a high-temperature solid-phase method was used to synthesize Pr3+ ion-doped Li2CaSiO4 matrix phosphor. An X-ray diffractometer and a fluorescence transient spectrometer were used to characterize the crystal structure and luminescence properties of the prepared phosphors. The results show that the prepared sample is a single phase of Pr3+-doped Li2CaSiO4; it exhibits a good orange light emission under the excitation of blue light, and is expected to be used as white light LED lighting
Thermo-sensitive hydrogel and their biomedical applications
Authors: Tian Meng Li , Zhou Jin Feng , Qi Xuejie , Shen Rui 
Published: April 2021

Abstract
Thermo-sensitive hydrogel has attracted considerable attention as a kind of intelligent material in the field of biochemistry and biomedicine. They have many kinds of advantages such as easy formulation to deliver hydrophilic and hydrophobic drugs, high drug loading capacity, convenient administration, sustained drug release capacity, target specificity by using injections thereby avoiding the need of surgery. Besides, thermo-sensitive hydrogel has attracted an increasing concern for its sustained release behavior, biocompatibility, and biodegradability. The biomedical application of thermo-sensitive hydrogel in the fields of tissue engineering, mucosal drug delivery, and local injection in recent years were studied in this review according to the latest relevant literature.
Intelligent Research and Upgrade of Narrow-band Hot-rolled Steel Production Workshop
Authors: Hao Xiaodong , Sun Changjie , Yang Chi , Li Lihua , Ma Yong , Yin Zihao 
Published: April 2021

Abstract
This paper expounds the process and equipment characteristics of the narrowband hot-rolled steel intelligent production workshop, introduces the key intelligent model content, explains the application effect after the completion of the intelligent workshop transformation, and points out the research significance and development trend.