bluuebunny/crossref_metadata_2025 huggingface dataset:
X-Ray Properties of PSR J1811-1925 by NuSTAR
Authors: Zheng Jin-Tao , Ge Ming-Yu , Li Xiang-Hua
Published: April 2023

We analyzed the spectral properties and pulse profile of PSR J1811–1925, a pulsar located in the center of composite supernova remnant (SNR) G11.2–0.3, by using high timing resolution archival data from the Nuclear Spectroscopic Telescope Array Mission (NuSTAR). Analysis of archival Chandra data over different regions rules out the SNR shell as the site of the hard X-ray emission while spectral analysis indicates that the NuSTAR photons originate in the pulsar and its nebula. The pulse profile exhibits a broad single peak up to 35 keV. The jointed spectrum by combining NuSTAR and Chandra can be well fitted by a power-law model with a photon index of Γ = 1.58 ± 0.04. The integrated flux of jointed spectrum over 1–10 keV is 3.36 × 10−12 erg cm−2 s−1. The spectrum of pulsar having photon index Γ = 1.33 ± 0.06 and a 1–10 keV flux of 0.91 × 10−12 erg cm−2 s−1. We also performed the phase-resolved spectral analysis by splitting the whole pulse-on phase into five phase bins. The photon indices of the bins are all around 1.4, indicating that the photon index does not evolve with the phase.
Fabrication of Carbon Coated Nickel/Nitrogen Doped Graphene Composite Film and as Enhancer for Sensitive and Rapid Determination of Sunset Yellow
Authors: Huang Guangjun , Li Sheng , Zhou Ying
Published: April 2023

The innovative glassy carbon electrode used in the determination of sunset yellow is modified using a carbon-coated nickel/nitrogen doped graphene composite film. (C-Ni/NGE/GCE). The morphology and structure of different materials (C-Ni and NG) were characterized by transmission electron microscope. When HAc-NaAc (pH=4) was selected as the electrolyte solution, the maximum current of C-Ni/NGE/GCE oxidation peak was reached when the electrolyte concentration was 0.15 mol·L−1, which was a reversible redox peak. The maximum linear range is 1.0×10−4 mol·L−1 and the minimum is 4.0×10−6 mol·L−1. Taking the peak current as the vertical coordinate and SY concentration as the horizontal coordinate, the working standard curve equation obtained by differential pulse voltammetry is Ip(μA)=0.187+56.91c (μmol·L−1 )(R2=0.9992). The detection limit was 5.0×10−8 mol·L−1. The electrochemical behavior of SY shows proton number (X=1) and electron transfer number (n=1). The recovery rate of SY in beverage was 101.5%-103.3%. The following research of sensor to nitrite was the linear range, recovery rate and uL, produced in small experiments.
Cone Angle Modulation of Silicon Nanocones through Double Etching Processes in Metal-Assisted Chemical Etching
Authors: Chen Hui , Bian Chenyu , Zhang Cheng , Wang Shaojun , Zhang Bingchang
Published: April 2023

All-wet metal-assisted chemical etching (MACE) has been demonstrated as a simple and effective method to fabricate silicon nanocones (SiNCs). The properties of SiNCs strongly depend on their structure parameters such as the cone angle and can be optimized through modulating the cone angle. However, cone angle modulation of SiNCs in all-wet MACE processes has not been achieved. Here, we report the fabrication of SiNCs with different cone angles through double etching processes in all-wet MACE. Large-size silver nanoparticles (AgNPs) were first obtained by solution deposition. After a common etching process, a double etching process with diluted etching solutions was introduced. In the etching step, AgNPs gradually reduced with the Si etching, which resulted in the formation of SiNCs. The cone angles of SiNCs depend on the changing rate of AgNP sizes. Based on this mechanism, SiNCs with different cone angles from 5°-20° were successfully fabricated by changing the concentration of the diluted etching solution in the double etching process. The contact angle of SiNCs with different cone angles was also investigated. It is found that the wettability of the SiNCs becomes poorer with increasing cone angles. Cone angle modulation of SiNCs in all-wet MACE will benefit the property control and the wide applications of SiNCs.
In Situ Fabrication of Nanoneedles with Hierarchical Structure Cobalt Nitride on Nickel Foam with Superhydrophobic
Authors: Gao Rui , Xie Yvfan , Zhang Tangjie , Kong Chao
Published: April 2023

Co5.47N nanoneedles with hierarchical structure were fabricated on nickel foam, and then grafting with 1H,1H,2H,2H-perfluorodecyltrimethoxysilane. The samples were characterized by scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The as-prepared nickel foam samples exhibited both super-hydrophobicity and super-lipophilicity. The water contact angle (WCA) of the as-prepared nickel foam was 156°, and oil drops could penetrate through the sample within 13ms. The superhydrophobic nickel foam can be used as an ideal material for oil-water separation, due to its superhydrophobic and superlipophilic properties.
Efficient Solution-Processed OLED Based on Thermally Activated Delayed Fluorescence Dendrimer with Butterfly Molecular Structure
Authors: He Yuting , Zhang Cheng , Yan Hao , Chai Yongshuai , Zhou Deyun
Published: April 2023

Solution-processed TADF dendrimer based on D-A-D structure has been synthesized, which named POtCz-DPyM. The dendrimers show a small ΔE
st. The performance of OLED device shows a relatively low turn-on voltage (4.2 V), the CEmax efficiency of 13.0 cd A−1, the EQEmax of 5.6%. Moreover, the POt modified carbazole was used as the donor to synthesize this novel dendrimer for the first time. And the solution-processed OLED based on POtCz-DPyM as emitter shows high performance among solution-processed devices.
Research Progress of Current Sensor Based on Spin-Dependent Magnetoresistance Effect
Authors: Zhou Bomeng , Li Tong , Pan Miao , Li Shufen , Su Jianzhi , Su Zhicong , Wang Feng
Published: April 2023

This article reviews the physical mechanism of spin-dependent magnetoresistance and its early application in sensors. The magnetic field performance generated by the current to be measured is explained. According to the realization of the magnetoresistance measurement of this characteristic, seven main indicators of the current sensor are summarized. Starting with the structure of magnetoresistance devices and magnetoresistance units of current sensors based on spin-dependent magnetoresistance effect, several design methods of sensors and their advantages and disadvantages are analyzed. Starting from the role of AMR, GMR and TMR in magnetoresistance cells, the structure of series and parallel arrays, permanent magnet bias, coil bias, coil reset, flux aggregator and superconducting ring are analyzed, and several design methods of sensors are summarized as well as their advantages and disadvantages. Finally, the possible development direction of the current sensor is forecasted based on the recently discovered spin correlation effect.
Effect of Normalizing on Impact and Corrosion Resistance of Low-temperature Service Seamless Steel Pipe
Authors: Zhao Bo , Ai Fangfang , Yuan Qin , Wu Hong , Cheng Junxia , Wang Shanbao , Xie Degang
Published: April 2023

The seamless line pipe, which has fine low temperature impact properties for Low-temperature Service and good H2S corrosion resistance, was investigated through chemical composition designing, optimizing smelting-rolling processes, and heat treatment processes following ASTM A333 standard. The influence of normalizing on the impact property and corrosion resistance was studied by optical microscope, scanning electron microscope, transmission electron microscope, mechanical test and corrosion test. It is demonstrated that the low temperature mechanical properties and anti-H2S corrosion properties of hot-rolled trial-pipe and normalized trial-pipe meet ASTM A333 standard. The microstructure of hot-rolled trial-pipe is pearlite and ferrite, and the grain distribution is uniform and grain size is fine. The dominated precipitates phase are TiN particles in hot-rolled trial-pipe. Ductile to brittle transition temperature is determined at -60 °C. The grain refinement is achieved after normalized and the main precipitates are TiN particles together with a few VN particles. Ductile tobrittle transition temperature was further lowered, at - 80 °C. The corrosion behavior of the material was examined by hydrogen induced cracking (HIC) corrosion test, sulfide stress corrosion (SSC) test and polarization test at various polarization scanning rates. It is observed that the anti-HIC corrosion performance and SSC corrosion resistance are similar for both hot-rolled and normalized pipes, but the performance of electrochemical corrosion of normalized pipe is better than hot-rolled pipe, which indicates that the normalized pipe is more suitable for demanding corrosive environments.
Comparison of Punching Shear Behaviour of Two-Way Concrete Slab Reinforced with CFRP Grid and Steel Bars
Authors: Duan Ning , Zhang Jiwen
Published: April 2023

Two punching shear failure tests of two-way concrete slab reinforced by CFRP grid and HRB 400 steel were studied in this paper. The reinforcement ratio of slab reinforced with CFRP grid and HRB400 is 0.33% and 0.37 respectively. The upper and lower surfaces of the concrete slab’s tensile and compressive strains, the reinforcement strains, the load deflection of the slabs, and the applied load value were analyzed. The results show that under approximately the same reinforcement ratio, the concrete slab reinforced with CFRP grid has higher bearing capacity. Both slab failure formed with punching cones, the punching cone angle of CFRP grid slab is 24.1°, which is far less than 38° for reinforced concrete slabs. The tests results indicated that there is a cooperative between longitudinal and transverse limb of CFRP grid.
Analysis and Assessment of Prestressed Reactive Powder Concrete Box-girder Bridge with Corrugated Steel Webs
Authors: Ao Deng , Hu Guoxi , Xu Qiang
Published: April 2023

Prestressed concrete box girder bridge with corrugated steel webs is a new type of bridge which uses corrugated steel webs to replace the traditional concrete webs. Compared with the traditional box girder bridge, it has certain advantages and has been widely used in bridge engineering. Combined with the characteristics of prestressed concrete box girder bridge with corrugated steel webs and reactive powder concrete theory, this paper puts forward the concept of new prestressed corrugated steel webs reactive powder concrete box girder bridge. By improving the material properties, structural design and construction methods of prestressed concrete composite structure with corrugated steel webs, its bearing capacity can be improved, so as to improve its construction efficiency and economic benefits. The research shows that the prestressed reactive powder concrete box girder with corrugated steel webs has the advantages of light structure and convenient construction, and has superior mechanical properties and obvious economic benefits when it bears the equivalent external load of prestressed corrugated steel web concrete composite girder.
Research on the Measurement Method of Key Shape and Position Errors of Hemispherical Harmonic Oscillator
Authors: Zhao Yuqian , Li Fei , Liu Kexian , Liu Junfeng , Lai Tao
Published: April 2023

Hemispherical resonance gyroscope originated in the 1960s. With its outstanding advantages of high precision, simple structure and long service life, it is increasingly widely used in aerospace, tactical weapons and other fields. The hemispherical resonator, the core part of the gyroscope, is a thin-walled part with high steepness curved surface and hard and brittle material. Limited by the current processing level, it is difficult to obtain good shape and position accuracy, resulting in uneven mass distribution and frequency cracking, which affects the accuracy of the gyroscope. Based on the precision machining of hemispherical resonator, this paper carries out the research on the measurement method of shape and position error, focuses on the measurement method of the roundness and end face of the resonator, uses the cylindricity meter to complete the measurement of the roundness error of the inner and outer hemispherical shell of the resonator, and uses the white light interferometer and the subaperture stitching technology to realize the measurement of the full aperture surface of the end face of the hemispherical shell. This work provides theoretical guidance for subsequent processing and is of great significance to improve the quality of harmonic oscillator.
Jet Formation Characteristics of the Reactive Material Composite Liner Shaped Charge
Authors: Li Hongda , Liu Chengzhe , Chen Tinghao , Li Peipei , Duan Hui , Zhang Zhili
Published: April 2023

The formation characteristics of reactive material (RM) composite jet were studied by finite element software AUTODYN. The effect of diameter and thickness ratio, and cone angle of the liner on the tip velocity of composite jet and effective jet length were investigated. In numerical simulations, with increasing of the ratio of liner diameter, the ratio of liner thickness and the liner cone angle, the tip velocity of the composite jet decrease. With increasing of the liner cone angle, the effective length of composite jet decreases. But it is almost independent of the liner diameter and thickness ratio. When the liner diameter ratio is 0.6-0.8, the liner thickness ratio is 0.1-0.2, and the cone angle of composite liner is 60°-80°, the comprehensive performance of the RM-composite jet is better.
Large Eddy Simulation of Hydrofoil Tip Leakage Vortex
Authors: Hu Zilong , Pan Jiale , Tao Ran , Wu Yanzhao , Zhu Di , Xiao Ruofu
Published: April 2023

The axial-flow turbomachinery is important in water supply and drainage. However, there is a gap between the blade tip and the casing, which is easy to cause tip leakage vortex. Tip leakage of axial-flow turbomachinery has bad impact on the operation stability. In this case, the numerical simulation is used to study the simplified hydrofoil model with clearance. Then the change of tip leakage vortex core position and the pressure distribution are analyzed. Results show that with the fluid flows downstream, the longitudinal position of the tip leakage vortex core first drops and then rises. On different streamwise planes, the vortex core has the lowest pressure. From the downstream to the vortex generating position, the vortex core pressure decreases gradually, and the cavitation is most likely to occur at the location where the vortex occurs.
Preparation and Photocatalytic Properties of TiO2/MoS2 Composites
Authors: Yang Yanning , Wang Bangfu , Fan Yu , Ding Chen , Zhang Fuchun , Wang Haijun
Published: April 2023

The use of semiconductor photocatalysts to degrade organic pollutants and convert them into useful chemical energy is a promising technology to solve environmental problems. MoS2 and TiO2 have matching band structures. In this work, detailed characterization showed that TiO2/MoS2 complexes were synthesized by the hydrothermal method. It effectively increases the separation rate of photogenerated electron-hole pairs. In this paper, the photocatalytic degradation of rhodamine B (Rh B) by TiO2/MoS2 composites with different proportions under visible light was studied. The results showed that the Mo/Ti ratio would affect the photocatalytic activity. The composite had the best catalytic performance when the Mo/Ti ratio was 2:1. Compared with the intrinsic TiO2, its degradation rate increased by 60.28%.
Preparation and Characterization of Hydroxyapatite Nanotubes
Authors: Wu Jinan , Qi Liang , Nan Xiangkai , Sun Cuicui , Zhang Haijun , Qi Meili
Published: April 2023

As the key mineral component of human bones, hydroxyapatite (HA) has grasped much attention due to its outstanding biocompatibility, bioactivity and osteoconductive properties. Among different morphologies of HA materials, the special structure and good performance of HA nanotubes has been the focus of many scientific researchers. HA nanomaterials with hollow tube shapes have a relatively high surface area, low density and good mechanical property. However, the simple and convenient procedure to synthesize well distributed HA nanotubes is still rare. In this article, HA nanotubes with tens of nanometers in diameter and hundreds of microns in length were successfully synthesized via a simple solvothermal route. Calcium oleate and sodium hexametaphosphate are selected as the calcium source and phosphorus source, respectively. The surface structure of the HA nanotubes was observed under a scanning electron microscope. The synthesized HA nanotubes can be used in the area of adsorption, drug delivery and treatment of disease.
A Preparation Method of Ag-Decorated Cotton Fabrics with High Antibacterial Efficiency
Authors: Ma Hua , Li Minwei , Wo Zihao , Su Yier , Zhang Xiwen
Published: April 2023

In the present study, antibacterial cotton fabrics loaded with silver nanoparticle were prepared. The fabrics were first treated by plasma and alkaline solution to improve their reactivity. Then silver oxide nanoparticles were loaded on the fabrics by ultrasonic spray treatment. Finally, the fabrics loaded with silver nanoparticles were obtained by reduced the silver oxide in-situ via H2DBD cold plasma. The samples were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy and transmission electron microscopy. The results indicate that nanoparticles loaded on the final samples are fine, uniform and exist in the form of metallic state. The antibacterial performance of the samples was evaluated and the results indicated that the samples had antibacterial activity against bothEscherichia coliandStaphylococcus aureus. Therefore, the antibacterial fabrics prepared by this method have a potential application prospect in the medical fields.
Peak Stress of FRP-Confined Concrete Columns with Circular and Square Sections
Authors: Liang Meng , Chen Junwei , Ju Haoxue , Wang Yong
Published: April 2023

Fiber reinforced polymer (FRP) has been extensively used to strengthen concrete columns. It is necessary to establish peak stress model with high prediction accuracy for FRP-confined concrete columns. A theoretical peak stress model of actively-confined concrete is proposed based on Jefferson’s failure criterion. And a peak stress model for columns with circular sections (or concrete cylinders) is developed via the above theoretical model. By introducing the corner radius ratio ρ, a novel strength model for square concrete columns (or prisms) is further established. The proposed peak stress models are in good agreement with the experimental data covering the range of cylinder diameter D = 76 mm-610 mm, prism’s side length B = 100 mm-400 mm and the unconfined concrete strength f’c0 = 19.4 MPa-169.7 MPa. The established peak stress models are efficient due to the simpler expressions and high prediction accuracy.
A Quick and Convenient Route to Prepare Hydroxyapatite Porous Microspheres
Authors: Liu Yang , Qi Liang , Wang Ziqi , Zhao Yanwei , Zhang Haijun , Qi Meili
Published: April 2023

Due to the big specific surface area, good flowability and absorption ability, porous spherical HA materials have received extensive attention of the researchers. However, the facile and convenient synthesis of well-rounded HA microspheres with a porous structure is rarely reported. What’s more, the size of HA microspheres was usually less than 10 μm. In this study, by employing hexamethylenetetramine (HMT) as the pH regulator, hydroxyapatite (HA) microspheres with good uniformity and a diameter of 30-150 μm are successfully fabricated by a one-step hydrothermal homogeneous precipitation method. To our knowledge, the synthesis of such HA microspheres by using HMT has not been reported yet. Results show that the initial pH value plays a key role in regulating the morphology of the final products and the optimal initial pH value to obtain well-rounded HA microspheres with a porous structure is 3.0-4.0, especially around 4.0. The obtained HA microspheres can be utilized as effective drug carriers for biomedical field.
Design and Simulation of Two Stage Reduction Wheel-Edge Drive System
Authors: Shi Peilei , Xu Liang
Published: April 2023

The distributed driving system with electric wheel as key feature has become a major research issue in new energy automobile. However, wheel-edge driving system with reducing gear may cause significant increase of unsprung mass due to introduction of motor and reducer, which is negative to the vehicle maneuverability. As a result, this paper proposed a structural design of two stage reduction wheel-edge driving system which can convert unsprung mass into sprung mass, and established 1/4 three degree-of-freedom vertical vibration system model. Through simulation analysis, the effectiveness of such design was verified. Results showed that two stage reduction wheel-edge driving system can effectively suppress vertical vibration amplitude of automobile body, reduce vehicle dynamic tire loads, and increase riding comfort and tire ground adhesion.
Extruded 3D Printing Assisted Electrochemical Additive Manufacturing
Authors: Liang Yongqi , Xu Teng , Zhang Haiqing , Shi Shaoqi , Zou Yang , Yang Zefeng , Cheng Yuchuan , Li Zhixiang , Xu Gaojie
Published: April 2023

This essay investigates an additive manufacturing technique of an extruded 3D printing-assisted electrochemical deposition. The effects of solutions with different additive (Cl− and brightener) concentrations on the surface micromorphology and deposition rate of the formed films were investigated by using characterization data from test tools such as an electrochemical workstation, X-ray diffractometer, and scanning electron microscope, as well as discussing the laws of interaction between these two additives during the electrodeposition process. The experimental results show that when the concentration of Cl− in the copper plating solution is 2×10−3 mol/L and the brightener concentration is 10 ml/L, the electrodeposition experiments yielded deposited copper films with a significantly preferred orientation on the (111) crystal plane, and the prepared copper film has thicker deposited film and better surface quality. To validate the additive manufacturing method for extruded 3D printing-assisted electrochemical deposition, deposition experiments of 25-layer copper samples were carried out utilizing the best process parameters.
Failure Analysis of Ф73.02 mm × 5.51 mm S13Cr 110 Tubing Collapse in an Oil Field
Authors: Kuang Xianren , Hu Fangting , Fan Yujie , Li Kun , Jia Haidong
Published: April 2023

The field service conditions of a well’s collapse tubing were investigated, and the physical and chemical properties of metal materials (chemical composition analysis, mechanical property test, metallographic structure analysis of tubing materials), hydrogen sulfide stress corrosion cracking test of tubing materials, and scanning electron microscopy analysis of tubing cracks and fracture surfaces were tested in this paper. The results show that the major cause of tubing collapse is that the tubing material is super 13Cr (S13Cr). When it is used in the environment containing hydrogen sulfide, plenty of longitudinal stress corrosion cracks is generated on the inner wall, which greatly reduces the actual anti extrusion ability of the tubing. During the gas lift of the well in the later stage, the upper part of the oil pipe was blocked and the oil jacket was in series, and the gas lift pressure was transmitted into the oil jacket annulus, so that the pressure difference between the inner and outer parts of the oil pipe exceeded its actual anti extrusion capacity and collapse failure occurred.
Parameter Study of Purification of Low- to Medium-Grade Bentonite from Keerjian
Authors: Deng Lirong , Lu Yufeng , Dong Yongwang , Qin Jun , Li Shasha
Published: April 2023

In this paper, low- to medium-grade bentonite derived in Keerjian of Toksun county were characterized. A method combined by chemical dispersion and high-speed centrifugation was used for the purification of the bentonite. Absorption of methylene blue and X-ray diffraction analysis were used to evaluate the effect of purification methods. The result showed that the optimal slurry solid-liquid ratio, dispersant amount, sedimentation time, centrifugal speed, and time of centrifugation was 1:8, 1.2% of the bentonite mass, 24h, 2000 r/min, and 5 min, respectively. The investigation provided experimental evidence for the better development and application of bentonite in this mining area.
Effect of Tempering Temperature on the Structure, Morphology and Electrochemical Performance of LiNi0.5Mn1.5O4
Authors: Li Long , Li Shubo , Xi Quanfang , Zhao Qiaoli
Published: April 2023

LiNi0.5Mn1.5O4, the cathode material for 5V lithium ion batteries, was synthesized through the coprecipitation-combustion process in air. The effect of tempering temperature on the structure, morphology and electrochemical performances were investigated. The phase and electrochemical properties of the samples were characterized by powder X-ray diffraction, scanning electron microscopy and constant current charge-discharge tests. The experimental results indicate that the samples tempered at 800°C-900°C all have spinel structure, with the increase of tempering temperature, the crystallinity and grain size of the sample increase.The sample tempering at 850°C has well-developed crystals, moderate crystal size and the best electrochemical performance.
Fracture Analysis of Butt Welding Area of 5″ Drill Pipe Internal Thread End in an Oilfield
Authors: Hu Fangting , Zhao Mifeng , Geng Hailong , Feng Shaobo , Du Fenghui , Kuang Xianren
Published: April 2023

This paper tested fracture morphology analysis, mechanical properties and chemical, metallographic analysis and micro analysis to find out the factors of fracture in the butt welding area of the internal thread of the 5″ drill pipe, which is made of S135 in the casing pulling process of an oilfield. The results show that the chemical element, tensile strength and yield strength, impact performance, metallographic structure, inclusions in microstructure and grain size of the Fracture drill pipe meet the relevant data of the oilfield and industry standards, but the hardness of the fracture does not meet the requirements of the national standard. The important reason of the fracture of the drill pipe is that the oxide skin was not cleaned before the drill pipe joint was welded with the body. During welding, the oxide skin entered the molten weld metal, and large slag inclusions formed in the weld resulted. The secondary cause is improper subsequent heat treatment of drill pipe weld, which leads to increased weld brittleness and accelerated crack growth. This paper puts forward corresponding countermeasures to improve the quality of the drill pipe’s weld and prevent the failure accidents of drill pipe.
Study and Application of Remote Control Crawler Drilling Car for Mine Roadway
Authors: Wang Hongli , Jia Hongjun , Wang Shuyue , Cheng Wenquan , Lv Baoping , Song Lixin
Published: April 2023

With the rapid development of mining technology in coal mines, the technical requirements for safe production in coal mines are constantly improving. In addition, it is affected by the geological conditions of the coal mine, the section of the roadway and the manpower reduction. There is an increasing demand for automatic and intelligent equipment for coal mine. A crawler-type double-arm rock drilling car which can be operated by wireless remote control is developed. It can be operated by remote control and adjusted manually. It can not only drill small diameter ordinary boreholes, but also drill large boreholes with diameter of 100-120 mm. It can effectively solve the problem of larger free surface in straight-hole cutting blasting. It is safe in operation and high in excavation efficiency.
Study on Corrosion Fatigue Properties of the Welded Joints of SMA490BW Weathering Steel
Authors: Wang Qiuying , Qiu Peixian , Chen Beiping , Wu Xiangyang , Duan Weijun
Published: April 2023

The polarization curve test and corrosion fatigue test of SMA490BW weathering steel welded joints for high-speed train bogies were carried out by electrochemical workstation and fatigue testing machine, respectively, and the fatigue fractures were observed and analyzed by scanning electron microscope (SEM). The results show that: The mechanical properties of the SMA490BW weathering steel welded joints welded by MAG welding are good, the tensile strength is 519MPa, and the elongation after fracture is 26.67%. In 3.5wt% sodium chloride solution, the self-corrosion potential of the heat-affected zone is the lowest, the self-corrosion current density is the largest, and the corrosion resistance is the worst, the weld is in the middle, and the base metal is the best. The corrosion fatigue limit of SMA490BW weathering steel welded joints in 3.5wt% sodium chloride (NaCl) solution is 236.55MPa, which is much lower than the fatigue limit of 335.22MPa in air. SEM fracture analysis showed that the fatigue cracks of the joints in the air originated from the weld pores, while the corrosion fatigue cracks originated from the pitting pits on the surface of the specimens.
Numerical Analysis of Flow Field and Aerodynamic Noise in Intake Structure
Authors: Liu Hongda , Sun Dan , Sun Jingguo , He Jianyuan
Published: April 2023

The CFD numerical simulation was used to simulate the flow field and sound field of the intake system, combined with the acoustic finite element method. Based on the Lighthill acoustic analogy and the Möhring acoustic analogy method, the internal sound source distribution of the intake system, the intensity of the nozzle noise and the acoustic directivity were analyzed. Improvement measures were proposed from the perspective of noise transmission, and the influence of different wall thicknesses on the wall stimulated radiation noise, as well as the effects of attaching sound absorbing materials and spraying damping materials on wall radiation noise were studied.
Preparation and Photocatalytic Properties of Phosphotungstic Acid SiC Composites
Authors: Wang Xin , Zhang Danfeng , Hu Lin
Published: April 2023

Four kinds of PTA SiC photocatalysts with different proportions of PTA were prepared by impregnation from phosphotungstic acid (PTA) and SiC. The photocatalyst was characterized by UV-Vis diffuse reflectance spectroscopy, X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy and scanning electron microscopy. Rhodamine B (RHB) was used as degradation substrate to investigate the photocatalytic degradation performance of the photocatalyst. The results show that the prepared photocatalyst maintains both the support structure of SiC and the Keggin structure of PTA. PTA SiC with 40% mass fraction of PTA had the best photocatalytic degradation performance. When exposed to light for 180 min, RHB can reach 66% of the degradation efficiency and the photodegradation reaction rate constant was 5.21×10−3 min−1. As an active substance, hydroxyl radical plays a decisive role in photocatalytic degradation of RHB.
A Prediction Model for Recycling Amount of Recycled Metal from Waste Power Battery
Authors: He Sichao , Hu Song , Wu Shuanghe , Wang Pan
Published: April 2023

Dependency on importing lithium, nickel and other battery metal resources is increasing. It has an impact on the safety of the supply chain of NEV power batteries. Therefore, ensuring supply of key metal resources is of great necessity to China’s NEV industry. The valuable metals Li, Ni, Co, Mn can be extracted from waste power batteries through recycling, which is conducive to reducing China’s dependence on foreign metal resources. In this paper, a model was established to predict the recycling amount of regenerative metal for power batteries in China. Meanwhile, the influence of regenerative metal on the production and supply of power batteries was analyzed. The results show that the contribution of renewable materials to the supply of Li, Co, Ni and Mn will gradually increase from 4%-7% in 2021 to 19%-54% in 2030 as the number of power batteries decommissioned increases from year to year. Under the background of carbon neutrality, waste power batteries will be used as a reserve of key metal resources, and become an important resource to be seized by major battery manufacturers and vehicle manufacturers.
CO2 Adsorption Based on Porphyrin Based Porous Organic Polymers
Authors: An Changwei , Zhang Jun , Guan Xianqi
Published: April 2023

In order to efficiently catalyze the cycloaddition reaction of CO2 and epoxy alkanes under mild environment and no catalyst, this paper designed and synthesized two kinds of porphyrin based porous organic polymers—porphyrin based porous organic polymer containing carboxyl group (ppop-cooh) and porphyrin based porous organic polymer containing quaternary ammonium salt ion pair. Quaternary ammonium salt cation anion pair nucleophilic groups and metal active centers were introduced into the polymer by pre- and post-modification respectively. The chemical structure and pore structure of the polymer were characterized by infrared spectroscopy and physical adsorption instrument, and its effect as a catalyst on the cycloaddition reaction of CO2 and epoxy alkanes was studied. From the results, it is demonstrated that the two polymers had a multistage pore structure with a specific surface area of 302 m2/g-514 m2/g. The synergistic effect of Lewis acid metal ions, nucleophiles and multistage pore structure in the polymer significantly promotes the cycloaddition reaction between CO2 and epoxy alkanes. Under mild conditions (80°C, 0.3 MPa, 24h), the selectivity and conversion of the reaction reach more than 99%. The polymer is repeated for many times. After use, it still has good catalytic performance.
Spatial-Temporal Variation and Trend Prediction of Jinghe Runoff Based on R/S and Mann-Kendall Methods
Authors: Xu Shifeng , Zhao Lixia , Gao Yajun , Jin Shuangyan , Zhang Lijuan
Published: April 2023

This paper used the R/S method and the Mann-Kendall method to analyze and study the Spatial-Temporal variation characteristics, future trends and runoff cycles of the Jinghe River Basin by using the runoff series data from different hydrological stations from 1956 to 2018. The results showed that the Jinghe River basin hydrological stations of Yuluoping, Yangjiaping, Jingcun and Zhangjiashan appeared abrupt changes in 2000, 1985, 1987 and 1995. The annual runoff at each station shows a clear trend of decreasing in the abrupt change year to 2018. The runoff cycle of different stations in the Jinghe River Basin is 9a-10a. The Jinghe River basin will continue its trend of decreasing runoff for some time to come as climate change and human activities influence it.
Wet Oxidation of Excess Activated Sludge from Coal Chemical Industry
Authors: Qin Shulin , Wang Zhongquan , Zheng Weicheng , Zeng Xu
Published: April 2023

Excess activated sludge produced from coal chemical industries has gained much attention, because of the huge volume and high hazardous risk of the sludge. The wet oxidation of coal chemical sludge was studied in this study by using a stainless steel batch reactor. The effects of reaction parameters, including the moisture content, the additional dose of sludge, reaction temperature and the additional amount of oxygen, were discussed. The results showed that the highest removal ratios of COD and TS could reach up to 72.3% and 56.4% respectively with moisture content of sludge 93%, initial oxygen pressure 1.7 MPa under 240°C for 60 min. The mass transfer processes of sludge and oxygen, and the reaction temperature, are very important parameters for the treatment. It was suggested that wet oxidation technology provides a suitable alternative method for the treatment of excess sludge from coal chemical industries.
Improvement of the Sludge Decomposition and Nutrients Release by a Treatment with Potassium Permanganate Combined with an Ultrasonic Process
Authors: Chen Jiandong , Li Haijie , He Ganfeng , Gai Yongwei
Published: April 2023

Ultrasonic decomposition of sludge is a popular method for sludge treatment. Potassium permanganate (KMnO4) was added to promote the reduction of sludge and hydrolysis efficiency. The effect of ultrasonic treatment (ULT) combined with potassium permanganate (KMnO4) preprocessing on the disintegration of waste activated sludge (WS) was studied in this survey. The results indicated that the combined pretreatment of KMnO4 and ULT (150 W, 20 min) significantly improved the decomposition efficiency and nutrient release efficiency of sludge. The volatile suspended solids (VSS) were lessened by 15.22%, which was 56.8% larger than that of raw sludge. The soluble proteins, soluble chemical oxygen demand (SCOD), polysaccharides, and volatile fatty acids (VFAs) were improved by 2005.1%, 464%, 669.8%, and 719.9% respectively. The deliquescent organic matter in sludge products also effectively decreased, demonstrating the effective promoting effect of KMnO4 + ULT. Mechanistic studies showed that ULT united with KMnO4 pretreatment could improve the biodegradability of soluble organic matter by generating reactive radicals, effectively disrupt the structure of cell walls, lyse extracellular polymers, and accelerate the liberation of organic matter. The composite sludge decomposition process further mitigates the harm of sludge to the environment and provides a cleaner and more efficient sludge reduction and utilization method.
Numerical Wind Tunnel Simulation for Pollutants Dispersion with Urban 2003
Authors: Liu Wusheng , Lv Sibo
Published: April 2023

A CFD numerical wind tunnel software was made to simulate the air flow and diffusion of pollutants in urban areas. This softeware is very compact. With the collaboration of the modelling tool AutoCAD and the post-processing software Paraview, a set of standardized numerical simulation process of atmospheric diffusion has been established. The model of the software is based on Open Foam open-source platform, which can perform 3D large-scale parallel operation, and solve 3D Navier Stokes equations on Computer cluster. Based on the observation data of iop9 from the 2003 urban joint field study in Oklahoma City, Oklahoma, the numerical wind tunnel is further evaluated. The wind and concentration field in the near and middle regions, as well as the wind speed, wind direction, friction velocity and turbulent kinetic energy (TKE) profiles in the urban wake region are compared between the numerical wind tunnel and the urban 2003 field experiment. The results show that the numerical wind tunnel can be an economic and effective tool to simulate the diffusion of pollutants in urban areas.
Role of Organic Matter in Reducing Nitrogen-Leaching Loss and Improving Yield of Stem Mustard and Corn in the Three Gorges Reservoirs
Authors: Chen Jieru , Tang Zhenya , Chu Jun , Wang Kaisui , Shi Xiaojun
Published: April 2023

The effects of organic and/or chemical nitrogen (N) fertilizer application on nitrogen leaching and mustard yield in the Three Gorges Reservoir area is still unknown. Four years’ fertilizer experiments, including organic matter and chemical fertilizer incorporation (MC), chemical fertilizer (CF), organic fertilizer (M), and non-fertilizer (Control) were used to understand role of organic matter and fertilizer incorporation in reducing nitrogen-leaching loss and improving yield of stem mustard and corn in three gorges reservoirs. Results showed that MC led to the highest yield, sustainable yield index, percent fertilizer recovery, and nitrogen agronomy efficiency and N uptake of stem mustard and corn. Leaching loss of N was significantly positively correlated with cumulative precipitation. CF treatments led to obviously higher N loss with the cumulative precipitation more than 44.3 mm. the N loss in MC treatment exceeded that in M treatment or control with cumulative precipitation more than 96.2 mm. Total amounts and concentration of N in leaching water followed the trends: CF> M > MC > Control. Organic fertilizer could reduce nitrogen-leaching loss and improve yield of stem mustard and corn with incorporation of fertilizer.
Evaluation of Fertilizer Inputs and Soil Nutrient Status in Apple Orchards in China
Authors: Men Xiaopeng , Fan Zongzhen , Wang Yanfang , Wang Yubin , Wang Yi , Han Zhenhai
Published: April 2023

Apple is an important horticultural crop in China and its production consumes large amounts of Chemical fertilizers. In a survey of more than 300 Chinese apple growers, we found that small farmers’ fertilizer inputs are blind. Current research lacks a comprehensive evaluation of fertilizer inputs and soil nutrient status for apple production in China, but the evaluation work will play a supporting role in the macro management decision of nutrient resources. In this study, a database of fertilizer inputs and soil nutrients in five major apple producing areas in China was constructed by means of data integration. Two main conclusions can be drawn from the analysis of the database. Firstly, the chemical N and P fertilizer inputs exceed the recommended use in all five production areas, and secondly, the organic matter content of orchard soils in the five production areas only reaches a maximum of level 3. The research shows that China’s agricultural authorities should carry out macro management of nutrient resources in apple orchards, so as to guide different producing areas to adjust fertilizer input according to their soil environment, so as to improve the utilization rate of fertilizer.
Study on Rice Phenological Differences under Heavy Metal Stress by Using Multi-source Remote Sensing Time-Series Images
Authors: Liu Tianjiao , Chen Jiankui
Published: April 2023

Heavy metal pollution is surveyed rapidly and accurately, which is of great significance for soil pollution control. heavy metal pollution on farmland results in phenological changes, and we can use remote sensing technology to observe these changes. In the paper, Normalized Difference Vegetation Index (NDVI) time-series is built based on multi-source remote sensing images. Savitzky-Golay filter (S-G filter) was applied for denoising and reconstructing the time series. NDVI time series were used to calculate phenological indicators. Five phenological indicators were selected, which include seasonal amplitude, growth rate, seasonal length, seasonal integral and base level, to study on effect of heavy metal stress on rice phenology. The results showed that differences in phenological indexes at different levels of heavy metal stress as well as the phenological indicators under the stressed condition were generally lower than those under mild and moderate stress. From the findings, it can be concluded that the superiority of remote sensing phenological information in the monitoring of heavy metal stress in rice, and a new method for distinguishing heavy metal stress in rice will be provided.
Load Forecasting Research of Markov Chain based on Data Modeling
Authors: Feng Haoxuan
Published: April 2023

The introduction of the electricity market plays an irreplaceable role in assisting the power industry to achieve stable operation and planning of the power grid, promoting the effective use and dispatch of electric energy, and avoiding the waste of resources. The role of load forecasting for the electricity market is self-evident, in the context of big data, by building a load forecasting model based on the Markov chain, and using the actual data of a certain region for simulation calculation. The results show that the Markov forecasting method can play a good role in medium and long-term power load forecasting, and can be used as a supplement to conventional load forecasting.
Research on Measuring Method of Drilling Parameters Based on Parameter Measuring Device
Authors: Fu Qiang , Mao Yachun , Kang Quanyu , He Liming , Bai Yu
Published: April 2023

Mainly aiming at the research on the method of measuring the multi-source parameters of blasting boreholes in open pits, using the multi-source parameters of the measuring device to calculate the minimum resistance line distance. Through the intelligent analysis of the minimum resistance line distance, the blasting effect is improved, and the secondary blasting caused by the increase of the block rate can avoid the phenomenon of sudden increase in blasting cost and waste of resources caused by the increase of the mass rate. It ensures the safe production of the mine and the safety of the lives and property of the surrounding people.
Thermoluminescence of Natural Quartz Grains Beside Huguangyan Maar Lake
Authors: Guo Jingyuan , Gao Mu , Xiong Zhengye , Wang Xiaochun , Liu Hao
Published: April 2023

In order to study the relationship between the thermoluminescence (TL) properties of natural quartz crystals and the irradiation history, the TL test of quartz particles was carried out on volcanic ash near Huguangyan Maar Lake in Zhanjiang City. The TL glow curve and dose response of quartz were measured. The parameters of TL traps are calculated, and the activation energies corresponding to the TL peaks of 260, 310 and 365 °C of quartz grains are 1.34, 1.44 and 1.51eV, respectively. The peak position of the TL glow curve changes mildly with the increase of irradiation dose of quartz particles, indicating that the energy of a TL trap is not a single value, but an energy distribution; in the range of 355 °C to 375°C, the TL sensitivity changes greatly with the increase of the historical irradiation dose.
Bayesian Method for Inverse Scattering Problem of Interior Cavity with Phaseless Data
Authors: Guo Wenke , Wang Yujie , Zheng Enxi
Published: April 2023

This paper is concerned with the inverse acoustic scattering problem of a sound soft cavity based on phaseless near-field data. By combining the reference circle technique with the Bayesian method, this paper presents a numerical algorithm to retrieve the shape of the interior cavity from phaseless data. In this paper, the well-posedness of the Bayesian method is discussed. The posterior distribution of the shape parameters is obtained by DRAM algorithm and the reconstruction of the cavity boundary is acquired by taking the average value of the posterior distribution.
A Heuristic Method for Solving Ship Floating Problems Based on Improved Particle Swarm Optimization
Authors: Shao Houhua , Xu Lijun , Liu Chunlei , Yin Yong
Published: April 2023

The study of ship floating balance plays a very important role in the safety of ships. According to certain conditions of ship statics, the nonlinear equations of ship balance can be established with relevant parameters such as ship weight, draft, heeling angle, longitudinal inclination angle and static moment. In this paper, motivated by the least square method, the nonlinear equations of floating equilibrium are transformed to a nonlinear programming problem. The draught, heel and trim of the ship are taken as variables, and inequality constrained by the actual situation. The penalty function for nonlinear programming is considered and minimized by particle swarm optimization. The proposed optimization method simplifies the calculation process by avoiding the calculation of parameters. Numerical results verify the efficiency of the proposed method.
Comparative Study of Bistable Vibration Energy Harvester Using Different Elastic Boundary
Authors: Li Xuefeng , Zhang Jingyu , Yang Kai , Li Renfu
Published: April 2023

This paper demonstrates a novel bistable energy harvester coupled with a nonlinear elastic boundary (NEB-BVEH). The nonlinear elastic boundary changes the dynamic response of the bistable vibration energy harvester and improves its performance by providing additional support for the inclined spring through coupled dynamics. This work considers the performance of bistable vibration energy harvesters using different elastic boundary under different excitation amplitudes, including bistable energy harvester with linear elastic boundary (LEB-BVEH) and NEB-BVEH with different horizontal spring stiffness. The comparative results show that the performance of NEB-BVEH and LEB-BVEH is approximately the same under small excitation amplitude. However, NEB-BVEH with adding horizontal springs can significantly improve performance compared to LEB-BVEH under larger excitation amplitude. Results of the investigated case show that the bandwidth of NEB-BVEH is increased by 89.31%. The output power is increased by more than 25%. A comparative study demonstrates the superiority of NEB-BVEH, which is very beneficial for energy harvesting.