bluuebunny/crossref_metadata_2025_split huggingface dataset:
First-principles study on electronic properties of twisted bilayer borophene
Authors: Wu Rongyao , Gao Yang , Wang Xiaoyuan 
Published: March 2021

Abstract
Borophene has received considerable investigations in recent five years that it is reported to possess a series of marvelous properties. However, most of the researches are about its monolayer form, the bilayer borophene, especially the twisted bilayer form which is a hot topic recently, has not been studied in detail. Herein, the first-principles calculations based on the density functional theory (DFT) method was performed to study the electronic properties of three kinds of twisted bilayer borophene that each kind of bilayer borophene is twisted to a certain angle in the plane. For the consideration of structural stability and calculation cost, the bilayer borophene are optimized to be 32.2°, 58.0° and 83.6° using an algorithm based on crystal matching theory. The charge density of relaxed twisted bilayer borophene shows the proximity of boron atoms. The analysis of band structure reveals that the twisted bilayer structure could separate the degenerate band and transform the bands to direct type, thus, modulating the resistance. In addition, a near-zero density of states could be found when bilayer borophene is twisted. This research could provide a basis for the applications of borophene, such as integrated electronic devices and micro/nano electronics.
Calculation of Power Consumption and Junction Temperature of IGBT Module in Inverter
Authors: Wang Bo , Tang Yong 
Published: March 2021

Abstract
Insulated Gate Bipolar Transistor(IGBT) is a fully controlled power electronic device with excellent comprehensive performance, which is widely used in various inverter units. At present, Infineon’s IPOSIM simulation is usually used to obtain the power consumption and junction temperature fluctuation of IGBT modules, but it is only applicable to IGBT modules produced by Infineon. In this paper, the power consumption of IGBT and diode is calculated, and the expression of junction temperature fluctuation is obtained based on junction-shell transient thermal resistance, which is suitable for common IGBT modules. Finally, simulation verifies the correctness of the calculation method.
Proton exchange membrane fuel cell multi-stack parallel gas supply and load-up experiment
Authors: Huang Zhiwei , Zhou Junbo , Cui Yuanshuai , Cao Jiaxu 
Published: March 2021

Abstract
Given the current situation that there is no parallel experiment of multiple stacks in China, this paper uses a fuel cell test platform independently designed and produced by a company to study the performance of three fuel cells. This article describes the construction of the experimental test platform and the multi-stack load-up experiment. The experimental results show that the power generation of the three fuel cells is almost the same, which are 9475W, 9385W, and 9512W. When carrying out multi-stack load-up experiments, it was found that as the number of stacks increased, the voltage efficiency continued to decrease. The Analysis revealed that the parallel gas supply method caused uneven gas distribution, which caused some fuel cells to be in a state of hydrogen deficiency. This article proposes amendments to this problem.
Study on the Rheological Properties of MPCS with Isopropanol/Water as Base Fluid
Authors: Zou Chuansheng , Lv Shan , Qiu Zhongzhu , Li Chunying 
Published: March 2021

Abstract
In order to obtain a good stability of micro-encapsulated phase change suspension, then study its rheological properties, herein formulated a phase change micro-capsulated suspension and utilized isopropanol/water mixed solution as the base fluid. The particle size distribution, viscosity and rheological properties of micro-encapsulated phase change suspension were measured at different concentrations. The effects of mass fraction, temperature on viscosity were discussed. Based on the classic viscosity formula, a correction factor was introduced to get higher precision viscosity formula. The results show that: a volume ratio of 1:1.75 of isopropanol/water suspension, suspension stability is up to 48h. It is also found that the viscosity decreases with the increase of temperature, but it increases with the increases of mass concentration. The fitted Tomas viscosity formula is reliable when the volume concentration is less than 15.58%, the error could be controlled within 5.7%.
Simulation and optimization of distributed energy system based on differential evolution algorithm
Authors: Ni Congqi , Qiu Zhongzhu , Li Chunying , Gao Guishu , Zheng Yurou , Wu Congcong 
Published: March 2021

Abstract
Many parameters can influence performance of a distributed energy system as it involves various kinds of equipment. Proper sizing of various equipment is of great significance for its efficient operation of such systems. This paper took a business district as the research object, predicted and analyzed the hourly cooling/heating load of the system during typical days of different seasons. Based on comprehensive consideration of the user’s usage pattern, load, equipment characteristics and other issues, gas engine was selected as the system’s prime mover, and the system structure was designed accordingly. Mathematical model was developed including gas engine, gas boiler, absorption chiller and other equipment. The differential evolution (DE) algorithm was applied to optimize the equipment capacity of the energy system, with the multi-objective of lower annual total cost and less annual emission. The annual pollutant emission of the plan C is the lowest in the results, which is more suitable for the business district. Compared with the traditional energy system, the annual total cost and pollutant emission of the optimized system were about 22% and 27% lower, respectively. The distributed energy system shows significant advantages.
Research on IGBT Limit Current Based on Heat Balance Analysis
Authors: Wang Bo , Tang Yong 
Published: March 2021

Abstract
Insulated Gate Bipolar Transistor(IGBT) is the most widely used fully-controlled power electronic device at present, and the rated DC current and maximum pulse current given in the manual can’t reflect the working limit current. In this paper, considering the influence of temperature, the electrical model of IGBT is extended to electro-thermal model, and the stable point, unstable point and critical point of junction temperature are obtained by combining IGBT power consumption-temperature curve and heat transfer curve, thus the limit power consumption at the critical point is obtained, and the limit current is designed. Finally, experimental verification is carried out.
Research on Electro-thermal Model Simulation of IGBT Switching Transient
Authors: Wang Bo 
Published: March 2021

Abstract
The electro-thermal model of Insulated Gate Bipolar Transistor(IGBT) can be used to simulate the operating characteristics of devices at different temperatures. Considering the relationship between internal parameters, semiconductor physical constants and temperature, the electrical model of IGBT at a single temperature is extended to an electro-thermal model which can reflect the working characteristics at different temperatures. This model takes into account both simulation accuracy and simulation speed. Finally, the IGB model is selected, and the IGBT switching transient at different temperatures is verified by experiments.
Research on Classification and Application of Comprehensive Energy Load of Important Users
Authors: Wu Tianjiao , Li Qifen , Yang Yongwen , Li Long , Ning Ning 
Published: March 2021

Abstract
Important load users are the lifeline of urban development, and their energy security system is not yet complete. According to the existing power load classification guarantee principle, the comprehensive energy load classification and guarantee measures of important users are discussed. At the same time, it analyzes the characteristics of existing security resources, selects the semiconductor manufacturing industry as the application scenario, and explores more possibilities for flexible configuration of security resources for users with important loads. Finally, the distributed energy system is proposed as a security resource for semiconductor companies, and it is used as a backup with the mains, replacing conventional diesel generating sets, and switching from cold standby to hot standby. This will reduce the initial investment in enterprise construction, improve the utilization of security resources, and the reliability of energy supply for important load users.
Role of graphene on the enhancement of near-field radiative heat transfer between two homogeneous lossy media plates
Authors: Gou Yuchun , Fang Junfei , Huang Jinguo 
Published: March 2021

Abstract
In this paper, the near-field radiative heat transfer between two semi-infinite plates with different temperatures, which are composed of homogeneous lossy media, has been studied firstly. Attributed to the evanescent wave generated by total internal reflection, the near-field radiative heat transfer is much larger than the far-field radiative heat transfer. And, the closer the distance between the two plates is, the greater the heat transfer is. Then, a graphene layer has been used to cover on the surface of the plate with lower temperature to study the effect of graphene on the near-field radiative heat transfer. The results show that the existence of graphene can promote the near-field radiative heat transfer due to the excitation of surface plasmon polaritons on the surface of graphene. In addition, the heat transfer varies with chemical potential of graphene, which indicates that the near-field radiative heat transfer can be controlled by an external gate circuit. In the presence of graphene, the thermal resistance between the two plates ranges from 6.7×10−4 to 0.18 K/(W/m2) and increases with the increase of the thickness of vacuum gap between the plates.
Numerical Analysis of Influence Factors on Operation Performance of an Axial Exhaust Condenser
Authors: Xu Wenqiang , Zhang Li , Niu Hao 
Published: March 2021

Abstract
Taking the axial exhaust condenser of one gas-steam combined cycle unit as the research object, the steam flow in the shell side of the condenser was simulated under summer operating conditions. The flow distribution of the condenser in the shell side was obtained. Through the extraction of simulation data, the pressure of the condenser was obtained. The simulation results of single factor influence showed that the main factors leading to high operating pressure of the condenser under summer working condition were steam load, circulating water inlet temperature, circulating water flow and vacuum tightness.
An Improved MPPT Method with Dynamic Voltage Error Compensation under Two Varying External Conditions
Authors: Liu Sijia , Huang Yong , Dai Gaoqiang , Zhou Xun 
Published: March 2021

Abstract
This paper presents a new maximum power point tracking (MPPT) method which can improve the dynamic tracking ability under two varying external conditions, rapid irradiance variation and grid voltage fluctuation. Different from irradiance variation, the dynamic error of tracking voltage caused by grid voltage fluctuation is usually ignored by MPPT methods. The dynamic error of tracking voltage can make the unexpected power change of photovoltaic system and influence the dynamic MPPT efficiency. According to the different current increment changes under the irradiance variation and the grid voltage fluctuation, the reasons of dynamic voltage errors are analyzed and distinguished. And two corresponding modes of variable step size are designed in the tracking algorithm to regulate the voltage deviation from MPPs. The effectiveness and the improved dynamic tracking performance of the proposed MPPT method are verified by simulation results under the above two varying external conditions.
Effect of in Situ Formed Emulsions on Enhanced Extra-Heavy Oil Recovery by Surfactant Flooding
Authors: Wang Xiuyu , Wang Xiaoqiu , Lei Lichuan , Guo Yang , Yang Yongzhi , Xu Yaping , Hao Huimin 
Published: March 2021

Abstract
Thermochemical flooding is becoming more popular nowadays as a subsequent EOR method after thermal recovery in extra-heavy oil reservoirs. During this process, in-situ emulsions could happen due to interfacial active components existing in heavy crude oil. The enhanced oil recovery is inevitably related with the formation of emulsions, which is one of the main mechanisms and deserves a thorough study. Also, the features of relative permeability curves during thermochemical flooding should be investigated further, because they are very important but usually are difficult to obtain since physical reactions could happen.
Based on core-flooding experiments, combined with careful observation of produced crude oil emulsion morphology, this paper compared and analyzed the features of relative permeability curves and displacement efficiency at different conditions, and the mechanisms of extra-heavy oil production by surfactant displacement is then investigated. The surfactant used are provided by the oilfield at a varied mass fraction of 0.1%, 0.2% and 0.3% and under temperature of 100, 150 and 180 °C. The relative permeability data were processed with JBN method.
The experimental results show that both the oil and water relative permeability increase as the temperature increases. As surfactant concentration increases, the relative permeability of the aqueous phase decreases as opposite to oil. The ultimate recovery increased with the increase of temperature and surfactant concentration. Except for the oil viscosity reduction by surfactant, it is interesting to note that the formation of crude oil emulsions (mainly O/W emulsions) are observed to be positively impacting the oil recovery factor. As surfactant concentration increases, larger size of dispersed phase in the emulsions were observed in the effluent corresponding to a higher oil recovery factor. This work is of great significance for heavy oil research and field development.
A novel direction relation reasoning model based Environmental Protection GIS
Authors: Xiang Jun 
Published: March 2021

Abstract
To make the complicated environmental protection work simple, environmental protection GIS is widely used. Direction relation reasoning is an important branch of spatial reasoning, it is also one of the most basic theoretical issues in the Environmental Protection Geographic Information System. This paper proposes a modelling method of combining the cone-shaped direction relation model with the direction relation matrix to determine the fuzzy direction relation between spatial entities on the basis of the cone-shaped direction relation model and direction relation matrix in Environmental Protection Geographic Information System, the advantages of the two models are fully utilized to overcome the disadvantages of them. Firstly, “central-region” is divided into nine equal internal sub-regions on the basis of the Minimum Bounding Rectangle (MBR) model. Then, the central-region of the direction relation matrix is divided again by using the cone-shaped direction relation model, and a fuzzy formal description model is given by taking point entity and area entity as research objects. The application of direction relation reasoning model in Environmental Protection GIS is helpful to improve the efficiency of judging the direction of pollution sources and the level of environmental protection.
A brief analysis method in plant landscape design of motorway
Authors: Que Yi , Tang Haiyan , Zhang Zhiwei , Zhao Hengyi 
Published: March 2021

Abstract
Plant landscape design is one of the main contents of highway design. This paper sums up the principles and methods for plant landscape design based on the compositions of expressway landscape, and discusses in detail the point of plant landscape design for the green belt on both sides of the expressway, the central separation belt and the subsidiary green area.
Study on Start-up Performance of Anammox Process
Authors: Li Yafeng , Wu Jianbo 
Published: March 2021

Abstract
Anammox, as one of the most revolutionary new denitrification technologies so far, has broad application prospects. In order to explore the start-up process of the anaerobic ammonia oxidation process, the experiment was conducted to domesticate anaerobic sludge in an up-flow anaerobic sludge bed reactor. The results showed that the reactor reached a stable operation stage from the 95th day to the 112th day. The removal rate of NH4
+-N and the removal rate of NO2
−-N were stabilized at 94.12% and 97.70%, respectively. According to the removal of NH4
+-N and NO2
−-N in the reactor, the start-up process can be divided into 4 stages, and there is denitrification and synergistic anaerobic ammonia oxidation in the reactor.
Preparation of sulfamethazine molecularly imprinted polymer by electron beam irradiation polymerization
Authors: Liu J , Yuan K F , Liu J H 
Published: March 2021

Abstract
Molecularly imprinted polymers (MIPs) of sulfamethazine (SMZ) were prepared initiated by election beam irradiation in acetonitrile (ACN) with the use of SMZ as template molecule, acrylamide (MAA) as a functional monomer and ethylene glycol dimethacrylate (EGDMA) as a cross-linking agent. The combination of SMZ with MaA and EGDMA was studied by infrared spectroscopy. The adsorption kinetics experiment and selectivity of sulfamethazine imprinted polymers were investigated by ultraviolet spectrometry. The experimental results showed that there was a binding effect among SMZ, MAA and EGDMA. When the molar ratio of SMZ, MAA and EGDMA was 1 : 4 : 20, and the irradiation dose was 150 kGy, the adsorption capacity of MIP for sulfamethazine (Q
MIP) was the largest (31 mg·g−1). Furthermore, the imprinting factor (F) was 12.91, and the separation factor (α) for SMZ and sulfonamide (SNM) was 1.77.
Effect of Low temperature treatment on dormancy release of Sedum aizoon L.
Authors: Liu Yuhang , He Zhongqun , Zhang Ruijie , Li Chunyan 
Published: March 2021

Abstract
The dormant Sedum aizoon L.seedlings were treated with different days(1d, 3d, 5d and 7d) of low temperature (5°C), and restored to grow for 40d (25°C).The growth indexes, photosynthetic characteristics and carbohydrate metabolism indexes were measured to compare the dormancy relieving effects of the seedlings. The results showed that Sedum aizoon L. was physiologic dormancy, and the effect was the best when it was treated at 5°C for 5 days, and the dormancy was completely relieved.
Application of Ergonomics in Health Care
Authors: Chen X , Wang X , Ai Cq 
Published: March 2021

Abstract
This paper defines the definition of human ergonomics, and introducing human ergonomics as an important subject in the medical and health services, and discusses the technical skills associated with human ergonomics and medical and health services, let us on the non-technical skills in medical and health services with the understanding of the important role. This paper analyzes the current situation of some non-technical skills in our hospital, and summarizes some effective methods and measures at home and abroad to reduce the influence of human factors in recent years.
Design and research of underwater hydraulic driven diamond chain saw cutting machine
Authors: Yang Shao-Rong , Wang Zhi-Ming , Yu Yue , Lu Yun-Feng 
Published: March 2021

Abstract
The hydraulic driven chain saw is a cutting tool for underwater operation. The hydraulic driven chain saw was designed, the hydraulic adjusting device was designed, the hydraulic chain saw experimental platform was designed, the sawing efficiency and power consumption experiments were carried out, and the diamond saw chain wear experiment was carried out. The experimental results show that:When cutting C25 standard reinforced concrete floor plate, the tension of tight edge of diamond saw chain is large; the dynamic load of diamond saw chain has the greatest influence on the tension of diamond saw chain, and the dynamic load is proportional to the rotation speed of chain wheel, the pitch of diamond saw chain, the weight per meter of diamond saw chain and the length of tight edge, among which the rotation speed of chain wheel has an effect on it The noise is the largest; the power consumption of cutting concrete is 2.85kw, the efficiency of sawing concrete is 0.93m2/h, and the sawing area of diamond saw chain per meter is 16.7m2/m.
Bacillus tequilensis Isolated from Fermented Intestine of Holothuria Scabra Produces Fibrinolytic Protease with Thrombolysis Activity
Authors: Hidayati Nur , Nurrahman Nurrahman , Fuad Hayatun , Munandar Hendra , Zilda Dewi Seswita , Ernanto Aditya Rahman , Samiasih Amin , Oedjijono Oedjijono , Ethica Stalis Norma 
Published: March 2021

Abstract
Among essential treatment of cardiovascular disorders are fibrinolytic proteases. Most thrombolysis agents are fibrinolytic enzymes from group of bacterial proteases. This work reports a potent bacterium isolated from fermented intestine of H. scabra, which could produce fibrinolytic protease with high thrombolysis activity. Bacterial selection was conducted based on proteolytic and fibrinolytic activities indicated as clear zone on skim milk and fibrin agar media, respectively. Crude proteases from the selected bacterial isolates were subjected to thrombolytic activity test based on gravimetric method, which results were confirmed after 7 repetitions. As result, 4 fibrinolytic protease-producing bacterial isolates HFSI-3, HFSI-4, HFSI-5 and HFSI-8 were obtained. Among them, HFSI-5 isolate identified as Bacillus tequilensis on the basis of the 16S rRNA gene sequencing and morphological properties produced crude protease with the highest thrombolytic activity. The thrombolytic activity of crude protease produced by B. tequilensis HFSI-5 is worthy of comparing to that of standard fibrinolytic enzyme Nattokinase showing its potential as thrombolysis agent.
High-speed generation of singular beams through random spatial multiplexing
Authors: Hu Xiao-Bo , Ma Si-Yuan , Rosales-Guzmán Carmelo 
Published: March 2021

Abstract
Complex vector modes have become topical of late due to their fascinating properties and the many applications they have found across a broad variety of research fields. Even though such modes can be generated in a wide variety of ways, digital holography stands out as one of the most flexible and versatile. Along this line, digital micromirror devices (DMDs) have gained popularity in recent times due to their high refresh rates, which allows the generation of vector modes at kHz rates. Nonetheless, most techniques are limited either by the diversity of vector modes that can be generated or by the speed at which they can be switched. Here we propose a technique based on the concept of random encoding, which allows the generation of arbitrary vector beams at speeds limited only by the refresh rate of the DMD. Our technique will be of great relevance in research fields such as optical communications, laser material processing and optical manipulation, amongst others.