bluuebunny/crossref_metadata_2025_split huggingface dataset:
Research on Quantitative Analysis Method of Readers’ Demands in University Library
Authors: Xu Chuanjie 
Published: June 2021

Abstract
Readers’ demands analysis is an essential part of university library management. It is the key to improve reader satisfaction in daily service work. In order to adapt to the changes of The Times, improve readers’ satisfaction in an all-round way, and make university libraries provide better services for teaching and scientific research, in addition to vigorously building library books and materials, electronic resources, hardware facilities, library needs analysis is an essential part of university library management work. By using AHP method, this paper puts forward a method to quantify readers’ demands. Focusing on the mapping method, the paper presents the hierarchical model and the judgment matrix of readers’ demands. The values of the judgment matrix elements reflect the reader’s understanding of the relative importance of various factors, and generally adopt 1-9 reciprocal scale method. With the analysis of demands expression and level transformation, the ranking scheme of readers’ demands importance is present. Through this analysis and calculation, the weight index of readers’ different demands can be obtained, which can be used for further quantitative analysis. The proposed method can be used in the decision-making of University Library in the daily management of books and materials, and provides a new idea for improving the quality of library work.
Power Monitoring System of Laser Welding Equipment
Authors: Bo Wen , Yi Jiangang 
Published: June 2021

Abstract
In order to improve the operation stability of laser welding equipment, reduce the failure rate of equipment operation. This paper designs a power monitoring system of laser welding equipment based on computer technology and communication technology. The system is mainly controlled by STM32 series processor. The upper computer of the power monitoring system is designed by C# language and .NET framework. Each module between the system realizes communication through socket and serial communication. Through real-time monitoring and analysis of key data such as welding power of laser equipment in the process of laser welding production process, the system realizes the functions of digital monitoring, data query, data storage, segmented data acquisition, equipment control, equipment running state analysis and so on. On this basis, combined with the network technology, the system realizes the functions of remote data monitoring and remote device log export, so as to improve the extensibility of the equipment and improve the operation economy of the equipment.
Research on Handover Algorithm Based on Dynamic Beamforming in HSR Cutting Scene
Authors: Zhang Zepeng , Dang Jianwu , Li Cuiran , Xie Jianli 
Published: June 2021

Abstract
High-speed train passes through the cutting terrain, signal propagation is significantly affected by the steep sides, resulting in a high probability of handover interruption. To solve this problem, this paper proposes a location-assisted dynamic beamforming handoff algorithm. This solution uses the vehicle-mounted GPS and the arrival angle of the incoming wave to determine the location of the Mobile Relay Node (MRN) and ensure the stability of signal transmission during the operation of the train in the overlapping area. According to the path loss of the High-speed Railway (HSR) cutting scene, calculate the Handover Interruption Probability (HIP), the Handover Trigger Probability (HTP) and the Handover Success Probability (HSP). The simulation results have showed that the proposed algorithm has lower HIP and higher HSP, compared with the traditional handover solution. It ensures the stability of handover in complex scenes, and has better performance in improving the handover efficiency of HSR communication systems.
Multi-objective game theory optimization for balancing economic, social and ecological benefits in the Three Gorges Reservoir operation
Authors: Yu Yang , Zhao Rui , Zhang Jiahe , Yang Douqiang , Zhou Tianyu 
Published: June 2021

Abstract
Reservoir operation is an important and effective measure for realizing optimal allocation of water resources. It can effectively alleviate regional scarcity of water resources, flood disasters and other social problems, and plays an important role in supporting sustainable strategic development of water resources. Coordinating the stakeholders is key to the smooth operation of a multifunctional reservoir. This research examines the competition among stakeholders of a multi-objective ecological reservoir operation aiming to provide for economic, social and ecological demands. A multi-objective game theory model (MOGM) specified 10-day water discharge to meet the triple water demands (power generation, socio-economic consumption and environment) for multi-purpose reservoir operation. The optimal operation of the Three Gorges Reservoir (TGR), with the ecological objective of providing comprehensive ecological flow demanded for some key ecological problems that may occur in the middle and lower reaches of the Yangtze River, was chosen as a case study. Discharged water calculated by the MOGM and a conventional multi-objective evolutionary algorithm/decomposition with a differential evolution operator was then allocated to different demands. The results illustrate the applicability and efficiency of the MOGM in balancing transboundary water conflicts in multi-objective reservoir operation that can provide guidance for the operation of the TGR.
Research on the influence of new energy vehicle enterprise operation decision under the background of sharing economy
Authors: Li Y D , Liu F 
Published: June 2021

Abstract
At present, China’s energy structure is mainly based on fossil fuels, which has brought serious problems such as environmental pollution, low energy efficiency and poor development quality. In the automotive industry, in order to save energy and protect the environment, many countries are actively promoting the production of new energy vehicles, optimizing the use of resources and benefits, and achieving green development. Based on the idea of sharing economy, this paper constructs a two-stage model. Considering the different quality of new energy vehicles in the two stages, optimization theory, game theory and other methods are used to study the influence of sharing behavior on enterprise operation decisions, and the following conclusions are drawn. First, in the presence of product sharing, product quality is negatively correlated with the optimal profit of the enterprise. Second, there is a negative correlation between the charging rate of the third-party platform and the optimal profit of the enterprise, and with the increase of the charging rate of the platform, the decline of the optimal profit of the enterprise is less and less. Third, when product sharing exists, the ratio of product quality in the two stages is positively correlated with the optimal profit of the enterprise.
Equilibrium Analysis on the Main Energy and Ancillary Service Joint Market Considering Load Aggregators
Authors: Ye Qiang , Wang Xi , Ren Zhichao , Wang Haiyan 
Published: June 2021

Abstract
In-depth mining of the adjustment capacity and value of demand-side load resources under the background of marketization is an important support for realizing the safe operation of the power grid and efficient operation of the power market in the future. This paper takes the load aggregator as the object, exploring its market operation ability through the main energy and ancillary service joint market simulation analysis. Firstly, the transaction framework of main energy market and frequency modulation ancillary service joint market considering load aggregators is built, then the market participation mode and the cost of each entity are analyzed. Secondly, based on the game equilibrium theory of oligopoly competition, a load aggregators included multi-period equilibrium model of energy and frequency modulation ancillary service joint market is established. Finally, the nonlinear complementarity method is applied to solve the model, and the rationality and effectiveness of the proposed model are verified through typical case analysis. The results show that with the participation of load aggregators, the effect of “peak shaving and valley filling” on both load and active power price is obvious, up and down frequency regulation capacity prices of the system have decreased, and the downward adjustment is more prominent, the purchase cost is reduced, and the user profit and social welfare can increase. It provides reference for future market planning as well as EVA operation.
Analysis of Reverse Recovery Characteristics of Anti-parallel Diode
Authors: Wang Bo 
Published: June 2021

Abstract
Insulated gate bipolar transistor (IGBT) is widely used in various renewable green energy systems such as wind power generation and solar power generation at present. High-power IGBT modules usually include IGBT chips and anti-parallel diodes, and the transient characteristics of anti-parallel diodes will affect the external port characteristics of IGBT modules. Based on semiconductor physics and diode basic structure, this paper analyzes four stages of diode reverse recovery process, and describes the change process of turn-off time and stored charge by a step recovery process. Finally, the voltage and current waveforms of diode reverse recovery process are simulated and verified for a certain IGBT module.
How to use the atmospheric environmental self-cleaning capability effectively in China
Authors: Li Yating , Zhou Jingkun 
Published: June 2021

Abstract
Based on the analysis of the effectiveness and disadvantages of artificial intervention in the treatment of air pollution, this paper briefly describes the importance of the application of atmospheric environmental self-cleaning capability for the comprehensive prevention and control of environmental pollution. According to the concept and connotation of atmospheric environmental self-cleaning capability, and referring to the main methods of foreign atmospheric environmental self-cleaning capability, this paper puts forward some suggestions on how to effectively use atmospheric environmental self-cleaning capability in China, such as strengthening the research of atmospheric environmental self-cleaning capability in China, making full use of the dilution and purification effect of wind, using the purification effect of dry and wet deposition effectively, playing the purification effect of human-oriented design reasonably, speeding up the adjustment of industrial and energy structure in combination with the characteristics of regional self-cleaning ability level, and establishing a comprehensive and key self-purification ability system index. It hopes to provide a reference for China to achieve the goal of air pollution control.
Study on Spatial Distribution and Sustainable Development of Night Tourism Resources:Take the Central Guilin as an Example
Authors: Hu Hongmeng , Hou Yuxia 
Published: June 2021

Abstract
The concept of sustainable development organically unifies the long-term interests and short-term interests, overall interests and local interests, economic interests and social interests of a country or region, and finally achieves common, coordinated, fair, efficient and multi-dimensional development. Based on the theory of tourism sustainable development, the paper discusses the characteristics of tourism resources composition and spatial distribution in the central Guilin from the aspects of scale, per capita share and nearest neighbor index. It is found that there are various types of night tourism resources in the central Guilin, but the supply of resources is insufficient, and the spatial distribution type is condensed, which is characterized by “central agglomeration and zero stars around”. The imbalance in regional layout exacerbates the contradiction between the supply and demand of night tourism resources. The relevant departments should take the integration, uniqueness and economy as the planning principles, and promote the sustainable development of the night tourism market in the central Guilin by issuing the night tourism planning policy, optimizing the spatial layout, deepening the night tourism planning and development, and widening the marketing channels.
Review on application and research of trans-critical CO2 refrigeration system in food freezing and cold storage
Authors: Zhu Jie , Yang Dazhang , Xie Jing , Wang Jinfeng 
Published: June 2021

Abstract
As people pay more and more attention to environmental problems, the GWP and ODP of traditional halogenated hydrocarbon refrigerants are generally higher, and the natural refrigerants with low GWP are more mentioned. As a natural refrigerant, CO2 is excellent in safety and environmental protection. CO2 as a refrigerant also plays a role in various industries, especially in the food industry. In the actual use of CO2 trans-critical refrigeration system in food refrigeration, it is found that there are some defects in CO2 system. Therefore, in order to solve the problem of low efficiency in trans-critical CO2 cycle, this paper analyses the research of some technologies in trans-critical CO2 refrigeration system that can improve system performance, COP and refrigeration capacity, and summarizes the problems in recent years progress in energy efficiency. In this paper, the working principle, technical characteristics and the improvement of system performance of various improved technologies are discussed in detail, and the previous research is summarized.
Influencing Factors and Countermeasures to Promote the Large-scale Development of Rural Solar Houses in China
Authors: Li Xuesong , Dong Yaowu , Li Chenchen , Wang Zijie 
Published: June 2021

Abstract
The development and utilization of renewable energy, especially solar energy, is an important way to solve the problem that China’s rural conventional power grids cannot cover remote rural areas. It is also an inevitable requirement of China’s rural development strategy. This article explores the influencing factors of Chinese farmers’ vigorous promotion of the use of solar houses, studies relationships among perceived value, farmer’s attitude and willingness to convert traditional houses into solar houses. Using data collected by a questionnaire from 413 rural households in Chongqing, China, the results show that perceived value has a significant and positive effect on farmer’s attitude and willingness to convert traditional houses into solar houses. Most importantly, the results of this research show that farmers’ attitude partially mediates the effects of perceived value on willingness to convert. Finally, the study also proposes relevant suggestions for policy makers, marketing managers and further research.
On the Physical Mechanisms that Cause the Full Load Instability in Francis Turbines
Authors: Wack J , Riedelbauch S 
Published: June 2021

Abstract
Today, hydropower receives increased attention for the safe integration of volatile renewable energies as it is able to stabilize the electrical grid. For that reason, turbines are more often operated at off-design conditions with the drawback that undesirable flow phenomena like the full load instability can occur. To assess their hazard potential, it is of great importance to understand those phenomena. Even though the physical mechanisms behind the full load instability have been analyzed in the past, they are not yet fully understood. The goal of this study is to close this gap and to develop a complete understanding of the full load instability. Two-phase simulations of a Francis turbine at model scale are performed for a full load operating point that becomes unstable when the cavitation number falls below a certain threshold. The unsteady simulations are performed using the Zwart cavitation model and the SST turbulence model with applied curvature correction. For simulations at different cavitation numbers it is investigated how characteristic quantities like swirl number or cavitation volume differ between stable and unstable conditions. This allows getting a deeper insight into characteristic changes of the flow for the transition from stable to unstable conditions. It can be identified that the interaction between cavitation on the runner blades and the cavitating draft tube vortex plays a key role in the development process of the full load instability. All in all, a complete explanation for the development of the full load instability can be given. The new findings of this study allow proposing an adapted 1D model, which considers the occurrence of blade cavitation.
CAVITATION EROSION MECHANISM: NUMERICAL STUDY OF THE INTERACTION BETWEEN PRESSURE WAVES AND VAPOR BUBBLES
Authors: Leclercq C. , Fortes-Patella R. , Archer A. 
Published: June 2021

Abstract
Investigations on vapor bubble collapses dynamic were carried out by three-dimension simulations with the software Prototype Homogène Code_Saturne. The code solves, by applying a compressible homogeneous approach, the Euler’s equations coupled with transport equations (for the volume, mass and energy fractions) that model the phase changes and the thermodynamic effects. To close the system, the Stiffened Gas EOS (equation of state) was applied to link the pressure and the temperature to the internal energy and the density.
Different mesh types and computational domains were tested to study four configurations in water: a) the vapor bubble collapse in free-field case; b) the vapor bubble collapse near a solid wall; c) the collapse of a vapor bubble in free-field case and impacted by an external pressure wave; d) the collapse of a vapor bubble placed near a solid wall and impacted by an external pressure wave.
Pressure waves generated during these bubble implosions were studied and characteristic parameters (such as wave passage time and amplitude of the pressure peak applied at the solid wall) were calculated under different hydrodynamic conditions.
Simulations led to some expected phenomena such as: the bubble asymmetrical shape evolution when a rigid wall is present; observation of toroidal vapor cavities; generation of high amplitude pressure waves during bubble collapses and rebounds.
Original results obtained concern mainly the study of the interaction between external pressure waves and collapsing vapor bubbles. Analyses on the influence of the incoming external pressure wave amplitude on the bubble collapse time and on the pressure peak reached on the wall are also presented in the paper. The numerical study showed an amplification of the collapse pressure by the incoming pressure wave. This interaction mechanism between pressure waves and vapor structures leading to pressure amplitude amplification could be responsible for the material damages due to cavitation.
Experimental and Numerical Investigations of Erosion on Runner Seal of a Francis Turbine
Authors: Yonezawa K , Watamura T 
Published: June 2021

Abstract
To suppress sediment erosion in labyrinth seals is an important problem for hydro turbine design and operation. A numerical simulation was carried out to know the flow with solid particles and its influence on the erosion in the labyrinth seal. The result showed that the vortex took place in the intermediate space between the first and the second seal gaps and the solid particles impinged on the runner wall along the vortex. Experiments were also carried out to understand the characteristics of the flow with vortices in the labyrinth seal by changing the flow rate of the leakage through the seal. It was found that the vortex took place stably in the intermediate space regardless the flow rate of the leakage although the Taylor vortex pattern was significantly disturbed as the leakage flow rate increased.
Novel techniques for the analysis of dynamic pressure in penstocks
Authors: Chevillotte Fabien , Pavić Goran , Dubois Guillaume , Proulx Gilles , Gagnon Martin 
Published: June 2021

Abstract
This paper focuses on the analysis of dynamic pressure fluctuations in hydro-electric power plants. Pressure fluctuations are usually measured with remote sensors and the dynamic behaviour of the remote tubing line modifies the readings of dynamic pressure and thus introduces a bias. A method to characterize the remote tubing line and to correct the actual pressure is proposed. The corrected measurements are compared with those obtained using intrusive flush-mounted sensors as well as non-intrusive sensors (PVDF wires and strain gauges). Then, the technique to separate the forward and backward components of the obtained pressure pulsations is outlined. It is further shown how the pulsations and the hoop stresses can be reconstructed along the penstock. Finally, measurements carried out in a hydropower plant are presented to demonstrate the proposed techniques applicability for the analysis of dynamic pressure in a penstock. The results show that a pressure profile can be mapped along the penstock length which allows a comparison with the direct pressure sensor measurements.
Experimental investigation of sediment erosion in a double-suction centrifugal pump in sandy rivers
Authors: Qian Zhongdong , Su Jiahui , Guo Zhiwei , Yang Bing , Dong Jing 
Published: June 2021

Abstract
The characteristic of sediment erosion of the blade in a double-suction centrifugal pump is mainly studied because the blades of double-suction centrifugal pumps are widely observed to suffer severe erosion damage in water intake projects along the Yellow River. In order to clearly present the evolution of blade-erosion area for different sediment properties in real conditions, the experiment with multiple layers of paint method is designed. The obtained results show that the leading edge of the blade, suction side of the blade inlet, suction side of the blade outlet and pressure side of the blade outlet are easy to be observed with erosion. More important, relationships between the eroded area and operation time by using hyperbolic tangent function are firstly established, and this function can be used to predict the development of the eroded area of blades in long operation. The first section in your paper
Effect of the winglet on reduction of blade tip vortex from elliptical hydrofoil
Authors: Maeda S , Sano T , Iino M , Farhat M , Amini A 
Published: June 2021

Abstract
It is well known that the performance of the turbomachinery (losses, vibrations, noise, and erosion) is often affected by the trailing vortex from the blade tip (Tip Leakage Vortex; TLV) of the impeller or propeller, and sometimes cavitation occurs in the center of the vortex core (Tip Vortex Cavitation; TVC). Many researches on the vortex characteristics of isolated hydrofoil by numerical simulations or experiments have been done so far, however, the research on understanding the mechanism of the vortex control technique is not enough, and it is important to mitigate the effect of TLV or TVC, to enhance the performance of turbomachinery. In this study, numerical simulation and experimental investigation were carried out to clarify the effect of winglet, attached to the elliptical hydrofoil (NACA16020). Five different winglet patterns were tested, changing bending angle and direction. Experiments were carried out using the high-speed cavitation tunnel in Ecole Polytechnique Fédérale de Lausanne (EPFL). As for numerical simulation, it was carried out in the same condition of the experiment. As a result, it was clarified that TVC decreased as increasing the bending angle of winglet, and disappeared in the case of 90 degree bent toward pressure side. And it is clarified that the vortex strength, in other word, vortex core pressure is affected by the interaction of the leading edge vortex and the tip vortex, and in case of pressure side 90 degree bended winglet, both vortices were mutually affected and cancelled the strength of these vortices.