bluuebunny/crossref_metadata_2025_split huggingface dataset:
Threshold pressure experiment of liquid flows through nanochannels and tight cores
Authors: Xiao Jiajia , Song Fuquan , Jiang Jingjing , Liu Guanghao , Wang Lingyun 
Published: November 2021

Abstract
Compared with low-permeability oil reservoirs, tight oil reservoirs have more nanopores, complex pore structure, and more obvious nonlinear seepage characteristics. Under the macro-scale channel flow, the influence of micro-forces is often ignored, but micro-forces of the micro-nano-scale have become the main factors affecting the flow. The micro-nano-scale flow is different from the macro-scale flow, and the flow requires the force between the fluid and the micro-nano tubes. The article conducts the threshold pressure experiment of nanochannels and cores, and results show that exists a pressure threshold under liquid flows through nanochannels and cores. The influence of the threshold pressure gradient in the micro-nanochannels is analyzed, and it is found that the nature of the fluid and the diameter of the pores affect the threshold pressure of micro the tube; core experiments prove the threshold pressure gradient exists in the core. The main factors affecting the threshold pressure gradient of the core are the permeability of the core and the nature of the experimental fluid.
Physicochemical characterization of the performance of acidified modified eggshell cyclic adsorption of CO2
Authors: Cheng Hanhan , Gong Dehong , Zhao Ting , Wang Tingyi , Jiang Song 
Published: November 2021

Abstract
The CO2 calcium based adsorbent was prepared by using citric acid monohydrate, L(+)-tartaric acid, glacial acetic acid and L(-)-malic acid modified eggshell. The cyclic calcination/carbonation reaction of the adsorbent before and after modification was carried out by thermogravimetric analyzer to investigate the attenuation characteristics of the cyclic CO2 absorption performance of the calcium-based adsorbent after modification. XRD, N2 adsorption analysis and other methods were used for physical and chemical characterization. The phase composition, morphology, specific surface area and porosity of the acidified calcium based adsorbent were investigated. The results showed that: during 20 cycles of calcination/carbonation after 900°C pre-calcination, the maximum carbonation conversion of CIES900 modified with citric acid is significantly higher than that of the previous adsorbent, and its maximum carbonation conversion is 90.7%. The L(-)-malic acid modified adsorbent MAES900 significantly enhanced the carbonation cycle stability of the adsorbent before modification, and the cycle stability reached 92.9%.
Environmentally Friendly Cp*Co(III)-catalyzed C-H Bond Hydroarylation of Alkynes
Authors: Zhao JiaKai , Mou Qi , Niu RuiHan , Zhao RuYuan , Sun Bo 
Published: November 2021

Abstract
A facile synthetic method of Alkenylarene derivatives via cobalt(III)-catalyzed C-H hydroarylation with terminal alkynes has been presented. This helpful protocol provides a way to use terminal alkynes to couple with aryl groups through 1, 2-insertion, with high yield and good selectivity to obtain the corresponding hydroarylation products.
Comparative analysis of machine learning algorithms in water extraction
Authors: Li Aimin , Fan Meng , Qin Guangduo 
Published: November 2021

Abstract
There are many traditional methods available for water body extraction based on remote sensing images, such as normalised difference water index (NDWI), modified NDWI (MNDWI), and the multi-band spectrum method, but the accuracy of these methods is limited. In recent years, machine learning algorithms have developed rapidly and been applied widely. Using Landsat-8 images, models such as decision tree, logistic regression, a random forest, neural network, support vector method (SVM), and Xgboost were adopted in the present research within machine learning algorithms. Based on this, through cross validation and a grid search method, parameters were determined for each model.Moreover, the merits and demerits of several models in water body extraction were discussed and a comparative analysis was performed with three methods for determining thresholds in the traditional NDWI. The results show that the neural network has excellent performances and is a stable model, followed by the SVM and the logistic regression algorithm. Furthermore, the ensemble algorithms including the random forest and Xgboost were affected by sample distribution and the model of the decision tree returned the poorest performance.
Microstructural evolution along the build height of laser melting deposited TA15 alloy
Authors: Rizwan Muhammad , Ullah Rafi 
Published: November 2021

Abstract
This study emphasizes the TA15 alloy microstructural distribution fabricated by the laser melting deposition (LMD) technique. The motivation of the study is to analyze the microstructural features, such as grain or laths thickness, phase fraction, and porosity occurrence in the different regions along the build height, due to the complex thermal-solidification history during the laser melting deposition. During laser deposition of titanium alloy, the laser beam forms a melt pool, where the near-α and α+β alloys transform into a single β-phase, followed by rapid solidification. This process is repeated when a successive layer is deposited, where the previously deposited layers are re-melted. These thermal cycles can affect the parent microstructure in the previously deposited layers. It was identified from the results that the width of α-laths was larger in the regions near the top of the build component. In comparison, the bottom region near to substrate contained fine laths due to a steep thermal gradient and repeated thermal effect. The volume fraction of β-phase was higher in the bottom region, which could be regarded as the transformed β matrix due to the successive thermal effect in the α+β field. The results also showed shallow porosity existence in the top and near to top regions. According to the morphology and size, the formation of these pores can be attributed to the gas entrapment during the deposition process.
Experimental Study on Thermal Performance of Pre-formed Thin Heating Floor Filled with Shaped PCM
Authors: Yan Quanying , Ma Chao , Wang Wei 
Published: November 2021

Abstract
A shape-stabilized phase change material (PCM) with high-density polyethylene was prepared as the supporting material to be added to a pre-fabricated light and dry-type heating floor. A system for underfloor heating experiments was set up in the laboratory to test the effects of average supply and return water temperatures and different temperature differences on the thermal performance of two floor heating systems under 10 different operating conditions, respectively. The results show that the surface heat-flux density of a phase change floor (PCF) is higher than that of an ordinary one at the stable stage. The proportion of heat transfer to the heating room is about 13% higher in the phase change system compared to the normal system, and the heat loss is reduced by more than 10%. At the cooling stage, the surface temperature of PCF decreases slowly, compared to the rapid decrease of the ordinary one.
Establishment and Analysis of Simulation Model for Single-pass 20 Steel Spinning
Authors: Yang Yu , Yang Jiao 
Published: November 2021

Abstract
With the continuous advancement of computer technology, finite element simulation has been gradually applied to the analysis of plastic deformation of metals. If a strong spinning simulation model of 20 steel cylindrical parts can be established to effectively simulate the stress, strain and surface quality of the metal deformation process, it can provide a scientific basis for the setting of spinning process parameters, thus reducing the number of spinning process experiments to determine spinning process parameters.
Constructing hierarchically porous MnO/C composite to induce diffusion kinetics for high-performance lithium-ion batteries
Authors: Zeng Dong , Qi Kai , Qiu Yubing 
Published: November 2021

Abstract
Hybridization with transition metal oxide is broadly realized as an attractive way to smash the capacity limitation of carbon-base materials upon lithium storage. However, the influence of metal ions on the fast reaction kinetics of the electrode is still a confusing topic. Herein, a common molten salt method is displayed to fabricate hierarchically porous MnO/carbon composites. The addition of LiCl and KCl induces the fluid reaction substance by forming molten salt at a high-temperatures to beneficially achieve the activation and breaking of the carbon particles. The abundant porous and homogeneou carbon skeletons validly raise the ion/electron diffusion and transferability to prevent MnO particles from agglomerating, thereby inducing the diffusion kinetic. Moreover, the hierarchical porous MnO/carbon composite offers a highly invertible capacity of 851 mAh g-1 at 0.1 A g-1 and outstanding cyclic performance. This work has opened up a path for metal oxidation/carbon composite materials in electrochemical energy storage.
Study on water erosion and preventive measures of last stage blade of steam turbine
Authors: Wang Zhengxian , Liu Tong , Luo Renda 
Published: November 2021

Abstract
In the background of carbon peak and carbon neutralization, most thermal power plants are more involved in peak regulation and even in-depth peak regulation in order to absorb new energy such as wind power and Solar power. When the turbine is running under low load, the exhaust pressure decreases, which leads to the increase of exhaust humidity. More and more turbine blades have water erosion. The erosion of the last stage blades will worsen the dynamic performance of the turbine, increase the risk of the last stage blade fracture, and threaten the safe operation of the turbine. This paper studies the mechanism of the last stage blade erosion of steam turbine, and analyzes the main factors which influence the erosion with examples. Combined with the mechanism of water erosion, the relevant preventive measures are made for reference of power supply plant.
Effect of heat treatment on the microstructure and hardness of Al0.3CoCrFeNi high entropy alloy
Authors: Zhai Hailin , Zhang Siyi , Yang Dong , Wang Chenxue , Jiang Jishen , Ma Xianfeng 
Published: November 2021

Abstract
In this study, the cold-rolled Al0.3CoCrFeNi high entropy alloys were heat treated at 900°C for 30min and 1050°C for 20min, respectively, to investigate the effect of heat treatment on the microstructure of the alloy. The results showed that grain refinement occurred in the 900°C/30min annealed sample, while remarkable equiaxial grains and twins appeared in the 1050°C/20min annealed sample. The hardness of samples showed a decrease trend following: as-rolled sample, 900°C/30min annealed sample, and 1050°C/20min annealed sample, which can be attributed to the dislocation elimination caused by recovery and recrystallization.
Experimental Study on the Influence of Micron SiO2 on the Kinetics of Hydrate Formation
Authors: Wu Shuai , Li Mingzhong , Zhang Chongrui , Liu Chengwei , Zhao Shuai , Wei Zhe 
Published: November 2021

Abstract
In order to explore the kinetic mechanism of hydrate formation in a system containing micron-sized SiO2 particles, this paper uses a high-pressure reactor device with stirring function to record changes in pressure, temperature and torque during the growth of hydrates through a data acquisition system, based on the conservation of mass in the system The principle and gas equation of state calculate the kinetic parameters of hydrate formation such as gas consumption in the reactor, hydrate formation rate and induction time, and analyze the influence of particle size and particle concentration on the kinetic characteristics of hydrate formation based on the experimental results. The experimental results show that the particle content has no obvious effect on the average growth rate of hydrate in the range of 1%-7%, but increasing the particle content can effectively reduce the hydration induction time; when the particle size is in the range of 2.5-85 μm, the larger the particle size, the shorter the hydrate induction time and the greater the hydrate growth rate.
Parameter matching and simulation analysis of power system of pure electric vehicle
Authors: Geng Jiwei , Chi Qun 
Published: November 2021

Abstract
The consumption of gasoline and diesel for cars is beyond imagination. Along with these problems comes environmental destruction. In order to achieve the two major indicators of power performance and economy, the most critical component of electric vehicles --- the power system is optimized and improved, and simulation is used to verify it on this basis‥ It can be concluded that the maximum vehicle speed is greater than 120km/h, the maximum gradeability exceeds 30%, the cruising range reaches 178km.
U-shaped Hanging Ring Fracture Failure Analysis in 220kV Transmission Line
Authors: Huang Rong , Zhang Gefei , Xie Yi , Feng Chao , Wang Jun 
Published: November 2021

Abstract
The U-shaped hanging ring was fractured in B phase fault tripping of a 220kV transmission line. They are analyzed by using macroscopic inspection of fracture, hardness test, chemical composition analysis, fittings load calculation, metallographic structure analysis and scanning electron microscopy analysis. The results show that there is a current flowing through the ground wire when the high-speed rail passes through. Poor contact between the U-shaped hanging ring and the clamp steel anchor caused heating and then high temperature wear. Long-term operation eventually led to fracture.
CFD Analysis on the Mixing Effect of Orifice Diameter in Dxygen Mixer
Authors: Zhang Xiaofeng , Ye Jihong , Ye Mao , Chen Kezhen 
Published: November 2021

Abstract
Rapid and uniform gas mixing is one of the core technologies of the chemical industry. A three-dimensional physical model of the oxygen mixer is established to investigate the influence of orifice diameter on mixing uniformity. And the standard k-ε turbulence model and species transport model are used to simulate the gas mixing process by using the computational fluid dynamics (CFD) commercial software Fluent. The oxygen distribution in the downstream of the mixer is analyzed qualitatively and quantitatively. It is found that the oversized and undersized orifice diameter are not desirable. It is concluded that the mixing performance of the case 2 is the b-est. In case 2, the oxygen mixing uniformity of the outlet section reaches the minimum value, which is 0.0001, which is the optimal structure.
Research on Scale Model of Typical Tension String of UHVDC Transmission Lines under Ice-Shedding Loads
Authors: Liu Peng , Si Jiajun , Zhou Lixian , Zhu Kuanjun 
Published: November 2021

Abstract
Tension insulator string is one of the important components of transmission lines and it needs to have enough mechanical strength to transfer the load between conductors and towers. However, due to the large size of the tension insulator strings, it is usually impossible to carry out the true type experiments. In this paper, the dimensional analysis was adopted to establish the mapping scale models of typical tension strings, namely 8N42-50100-55P at first. Then, the load scaling ratios of three typical tension insulator strings were obtained based on the results of the ice shedding calculation on an actual UHVDC transmission lines. Finally, the dynamic experiments of the scale tension insulator strings were carried out to access the feasible of technical route and to provide a technical support for the following research.
CPS-SPWM Implementation Based on Multi - Controller Collaboration
Authors: Dang HongShe , Li JunDa 
Published: November 2021

Abstract
In order to improve the modularization degree of cascaded H-bridge converter and reduce the development cost, a modularized carrier phase shifted sine pulse width modulation (CPS-SPWM) based on multi-controller is proposed in this paper, which can easily increase or decrease the number of submodules in cascaded H-bridge. In order to solve the problem of coordination in multi-controller structure, a two-stage control structure is proposed, which uses the master controller to carry out closed-loop control for multiple slave controllers, and uses the approximate natural sampling method to realize digital CPS-SPWM modulation, which reduces computation and makes full use of controller resources. The experimental result shows that the stepped voltage waveform output by the proposed method at the AC side is of high quality and H bridge submodule is easy to be increased and decreased.
A condition based maintenance system for important auxiliary equipment of thermal power unit
Authors: Li Cunlin , Qian Zhong , Shen Wenling , Yao Shengping , Shi Xiaoxi , Yu Xiaoben , Bian Shaoshuai 
Published: November 2021

Abstract
Through the research and development of key technologies of condition-based maintenance for power generation equipment, a set of important auxiliary equipment condition-based maintenance system for thermal power unit has been developed, which realizes the functions of integrated display of equipment-related data, equipment modeling configuration tool, equipment condition monitoring, equipment deterioration trend warning, equipment fault diagnosis, equipment health status evaluation, maintenance decision-making and so on. By studying the comprehensive assessment model of health state of power generation equipment, the equipment can be analyzed and evaluated scientifically and comprehensively, and the health state of equipment can be controlled step by step, thus improving the reliability of equipment operation.
Application of VSG technology based on flexible parameter adjustment in PV unit grid-connected inverter
Authors: Zhao Penghui , Wu Peng , Zhang Shuai , Wang Ning , Li Yan , Hu Yuan 
Published: November 2021

Abstract
As a clean and effective renewable energy source, PV has been widely used in power systems. The application of VSG technology can effectively improve the system inertia reduction problem caused by the grid connection of PV and energy storage units. The virtual inertia and damping coefficient in VSG control have the unique advantages of being flexible and controllable. This paper designs a control strategy in which the virtual inertia and damping coefficient can be flexibly adjusted according to the system frequency, which further improves the operating performance of the PV and energy storage units based on VSG control. The frequency quality of the system is maintained. Finally, the effectiveness of the proposed flexible parameter adjustment strategy was verified through the simulation platform, which played a role in popularizing the application of the proposed strategy in engineering.
Heteroatom-doped hollow carbon material as an electrocatalyst for oxygen reduction reaction
Authors: Sun Tiantian , Wang Heng-guo 
Published: November 2021

Abstract
The development of highly efficient and stable non-precious metal electrocatalysts is essential for the oxygen reduction reaction (ORR). In this study, a simple polymerization pyrolysis method is proposed to prepare heteroatom-doped hollow carbon nanospheres (NPSC-800) by using Fe-BDC and phosphorus-containing polymers as precursors. The unique structure allows the catalyst to show good catalytic performance (Initial potential of 0.8786 V, a half-wave potential of 0.7576 V, and a diffusion-limited current density of 4.48 mA cm-2). This research provides an effective strategy for the synthesis of heteroatom-doped carbon materials with good ORR catalytic performance.
Evolution of Unidirectional Solidification Microstructure and Hydrogenated Treatment of Nb-Ti-Co Quasiperitectic Alloys
Authors: Wang Hao , Yan Erhu , Liu Wei , Di Chongbo , Cheng Jian , Huang Renjun , Ge Xiaoyu , Chu Hailiang , Zou Yongjin , Xu Fen , Sun Lixian 
Published: November 2021

Abstract
Titanium alloys have a wide range of applications, and the internal placement of hydrogen into them can modulate the microstructure of the alloys and thus have great potential for further development. However, few studies have been reported on the application of this technique to Nb-Ti-Co ternary alloys, which needs to be urgently investigated. In this paper, four types of alloys (Nb10Ti61Co29, Nb15Ti55Co30, Nb20Ti50Co30, and Nb25Ti50Co25) are selected near the eutectic point of the phase diagram to study their placement of hydrogen by both static and dynamic processes of hydrogen’s placements, focusing on the effects of the temperature, time, and hydrogen-flow rate of such processes on the amount of hydrogen placements. The relationship between the hydrogen replacement parameters and the mechanical properties of the alloys is constructed. The results show that the placed-hydrogen amount of Nb-Ti-Co as-cast alloy grows with the increase of hydrogen-flow rate and soaking (or holding) time, with an upper limit of the placed-hydrogen amount, and the pattern of the directionally- solidified alloys is similar to that of the as-cast alloys; however, at a certain soaking time and hydrogen- flow rate, although the placed hydrogen amount of both alloys rises with the increase of temperature, the placed-hydrogen amount of Nb-Ti-Co directionally-solidified alloys is always larger than that of the as-cast alloys. However, the amount of hydrogen placement in the Nb-Ti-Co directionally-solidified alloys is always larger than that in the as-cast alloys, and the amount of hydrogen placement decreases significantly as the growth rate of the alloys increases. In addition, the microhardness decreases with increasing growth rate in the directionally-solidified specimens, and the amount of hydrogen placement and microhardness increase with growing Nb content.
Mathematical modeling and experiment for hydraulic ejecting system of ceramic brick press
Authors: Zheng HongBo , Li MingJun , Bian QingQing 
Published: November 2021

Abstract
Taking the ejecting system of hydraulic system of 7200t ceramic brick press as the research object, the basic constitution and working principle of the hydraulic ejecting system are described, and its mathematical model is established and calculated. In order to verify the accuracy of the mathematical model, the experiment was carried out, and the experimental results were compared with the calculated according to the mathematical model. The two results were basically consistent, indicating that the mathematical model is accurate, and providing a theoretical basis for further research on the ceramic brick press.
The novel image encryption scheme based on three- dimentional coupled chaotic system
Authors: Ren Xudong , Yu Wanbo 
Published: November 2021

Abstract
In order to improve the complexity of chaotic mapping and the security of image encryption algorithms, this paper proposes a new coupled three-dimensional chaotic system based on sine mapping and lorenz mapping. Based on this chaotic system, a new color image encryption algorithm is proposed, which performs index position scrambling and Arnold scrambling on the bit plane of the plaintext image, and then performs an XOR diffusion operation on the scrambled ciphertext to obtain the final ciphertext image. Simulation experiments show that the algorithm has a large key space, a small image correlation coefficient, an information entropy value of 7.9921, and a good encryption effect.
Research and Application of Network Trusted Interconnection Technology
Authors: Xie Wenjia , Wang Zhe , Tang Ping , Zhang Zhongmin , Chen Longsheng 
Published: November 2021

Abstract
In order to solve the problem of reliable information transmission between data centers and data sources, between data sources and between data centers, as well as the "network island" communication problem, a dynamic MPLS VPN method is proposed, the principle and steps of the method are introduced, and how to apply the method to the supporting platform is explained in detail.