bluuebunny/crossref_metadata_2025 huggingface dataset:
A low-noise X-band microwave source with digital automatic frequency control for electron paramagnetic resonance spectroscopy
Authors: He Yu , Kang Runqi , Shi Zhifu , Rong Xing
Published: April 2023

We report a new design of microwave source for X-band electron paramagnetic resonance spectrometer. The microwave source is equipped with a digital automatic frequency control circuit. The parameters of the digital automatic frequency control circuit can be flexibly configured for different experimental conditions, such as the input powers or the quality factors of the resonator. The configurability makes the microwave source universally compatible and greatly extends its application. To demonstrate the ability of adapting to various experimental conditions, the microwave source is tested by varying the input powers and the quality factors of the resonator. A satisfactory phase noise as low as −135 dBc/Hz at 100-kHz offset from the center frequency is achieved, due to the use of a phase-locked dielectric resonator oscillator and a direct digital synthesizer. Continuous-wave electron paramagnetic resonance experiments are conducted to examine the performance of the microwave source. The outstanding performance shows a prospect of wide applications of the microwave source in numerous fields of science.
Ultrafast carrier dynamics in GeSn thin film based on time-resolved terahertz spectroscopy
Authors: Huang 黄 Panpan 盼盼 , Zhang 张 Youlu 有禄 , Hu 胡 Kai 凯 , Qi 齐 Jingbo 静波 , Zhang 张 Dainan 岱南 , Cheng 程 Liang 亮
Published: April 2023

We measure the time-resolved terahertz spectroscopy of GeSn thin film and studied the ultrafast dynamics of its photo-generated carriers. The experimental results show that there are photo-generated carriers in GeSn under femtosecond laser excitation at 2500 nm, and its pump-induced photoconductivity can be explained by the Drude–Smith model. The carrier recombination process is mainly dominated by defect-assisted Auger processes and defect capture. The first- and second-order recombination rates are obtained by the rate equation fitting, which are (2.6 ± 1.1) × 10−2 ps−1 and (6.6 ± 1.8) × 10−19 cm3⋅ps−1, respectively. Meanwhile, we also obtain the diffusion length of photo-generated carriers in GeSn, which is about 0.4 μm, and it changes with the pump delay time. These results are important for the GeSn-based infrared optoelectronic devices, and demonstrate that GeSn materials can be applied to high-speed optoelectronic detectors and other applications.
The growth and expansive applications of amorphous Ga2O3
Authors: Xi Zhao-Ying , Yang Li-Li , Shu Lin-Cong , Zhang Mao-Lin , Li Shan , Shi Li , Liu Zeng , Guo Yu-Feng , Tang Wei-Hua
Published: April 2023

As a promising ultra-wide bandgap semiconductor material, gallium oxide (Ga2O3) is attracting extensive attention of researchers due to its feasible growth process, appropriate bandgap of 4.4 eV–5.3 eV allowing for deep-ultraviolet (deep-UV) detection, good physical and chemical stability, high breakdown field strength and electron mobility, etc. Different from the strict processes for controllable crystalline Ga2O3 (usually refer to as stable monoclinic β-Ga2O3), amorphous Ga2O3 (a-Ga2O3) film can be prepared uniformly at low temperature on a large-area deposition substrate, suggesting great advantages such as low manufacturing cost and excellent flexibility, dispensing with high-temperature and high vacuum techniques. Thus, a-Ga2O3 extremely facilitates important applications in various applied fields. Therefore, in this concise review, we summarize several major deposition methods for a-Ga2O3 films, of which the characteristics are discussed. Additionally, potential methods to optimize the film properties are proposed by right of the inspiration from some recent studies. Subsequently, the applications of a-Ga2O3 thin films, e.g., in photodetectors, resistive random access memories (RRAMs) and gas sensors, are represented with a fruitful discussion of their structures and operating mechanisms.
Antibacterial Properties and Mechanism of Graphene Oxide with Different C/O Ratio
Authors: Zhao Haoqi , Gu Baoshan , Yang Peiyan , Yi Jinquan , Lv Xudong
Published: April 2023

Graphene oxide (GO) has been extensively studied in biomedicine area on account of its great antibacterial activity. However, there are many factors that affect its antibacterial performance, and its mechanism of action is still unclear. In this paper, our modified Hummer method was used to prepare high-purity GO, and reduced graphene oxide (rGO) with different oxygen content was prepared by controlling different vacuum thermal reduction times. The impact of carbon-oxygen ratio on the antibacterial features of GO was studied. It is found that GO inactivates bacterial cells through oxidative stress, and the oxygen-containing groups also play a vital role.
Toughening Effect of Graphene Oxide in WC-Co Cemented Carbide
Authors: Gu Qingyi , Zhang Xiaoxiao , Zhang Jun , Zhai Chonglin
Published: April 2023

To study the effect of graphene oxide (GO) addition on the microstructure and mechanical properties of WC-Co cemented carbides, sintered bulks were fabricated and characterized. The study shows that the GO added in cemented carbide have insignificant effect on the relative density and the crystalline size, therefore, the higher hardness is maintained. Moreover, the fracture toughness has increased by 29.1%. Bridging is found to be the main toughening mechanism in WC-Co-GO cemented carbide. GO can be expected to be used to prepare cemented carbide with both high hardness and high fracture toughness.
First-Principles Study of Electronic Structure and Magnetic Properties of SnO2Co-doped with Transition Metals (Mo, Ru, Rh, and Pd) and Oxygen Vacancies (VO)
Authors: Liu Chenxi , Shi Leiqian , Pang Guowang , Pan Duoqiao , Liu Jibo , Ma Lei , Wang Xiaodong , Liu Lizhi , Lei Bocheng , Zhang Lili
Published: April 2023

The formation energies, electronic structures, and magnetic properties of a series of SnO2systems co-doped with transition metals (Mo, Ru, Rh, and Pd) and oxygen vacancies (VO) were investigated using plane-wave density functional theory with ultra-soft pseudopotentials. The results show that the formation energy of the Mo-VO-SnO2system was the smallest among the doped systems, indicating that the system was the easiest to form. The net magnetic moments of the X-VO-doped SnO2systems (X = Mo, Ru, and Rh) are not zero, indicating that the systems are all in the ferromagnetic state. Among them, the Mo-VO-doped SnO2system had an enormous net magnetic moment, highest spin polarization rate, and best ferromagnetism, making it an excellent ferromagnetic candidate material. The ferromagnetism of the doping systems originates from the strong hybridization of the 4d orbitals of the unpaired electrons in the dopants. The VO-SnO2does not exhibit any magnetic properties. Therefore, VOdoesn’t play a role in the generation of magnetism
Tm3+/Tb3+/Eu3+ tri-doped Na2O-BaO-B2O3-P2O5 Glass Material for White LEDs
Authors: Dong Xingui , Tang Jian , Tang Yongfeng , Qin Lina , Xing Junhao , Chen Guohua
Published: April 2023

The Tm3+/Tb3+/Eu3+ tri-doped borate glasses were fabricated by melt quenching method, and the structure, spectral characteristics and illuminant behaviors were characterized by XRD and fluorescence spectrophotometer. Through the measurement of photoluminescence spectrum and fluorescence decay lifetime, the fluorescence decay of Tm3+ at 452 nm and Tb3+ at 542 nm shows a faster trend, which confirms the energy conversion process of Tb3+→Eu3+ and Tm3+→Eu3+. The color temperature 5615.51K and color coordinate (0.3295, 0.3566) of the 0.5Tm3+/1.0Tb3+/0.5Eu3+ (mol%) tri-doped glass sample are close to the standard white light color temperature 5454.12K and its color coordinate (0.3333, 0.3333). It is expected that it will become a candidate material for white LED and light-emitting display, and has broad prospects.
Effect of SiO2 Adding on Properties of SiC Porous Ceramic Support
Authors: Xue Ridong , Yu Tianyi , Song Haibo , Sun Yanan , Deng Xiangyun
Published: April 2023

In this paper, The binders were prepared with different proportions of potassium feldspar, kaolin and quartz. In order to optimized the performance of SiC porous ceramics, the influence of binders with different content of SiO2 on the bending strength, filtration pressure drop and stomatal rate of porous ceramics were explored. The results show that doping of 10wt% SiO2 in the binder can improve the mechanics performances of SiC porous ceramics. Samples prepared by thermal insulation for 90 minutes at 1300°C had the best comprehensive performance when the adhesive contained 10wt% SiO2. At this time, the porosity was 25.52%, the bending strength was 47.15 MPa, and the filtration pressure drop was comparatively low.
Microstructures and Properties of TiSiN/TaVN Nanomultilayers with Various V Contents
Authors: Yan Hongjuan , Mi Zhifeng , Li Chunyang , Liu Yifeng , Liu Fengbin , Si Lina
Published: April 2023

The purpose of this study was to optimize V content of TiSiN/TaVN nanomultilayers. TiSiN/TaVN nanomultilayers with various V contents were deposited on 304 stainless steels and Si wafers. The structures and properties of TiSiN/TaVN nanomultilayers were analyzed and characterized. The results show that TiSiN/TaVN nanomultilayers exhibit the face-centered cubic (FCC) structure and preferred orientation on the (111) and (200) planes. With the increasing of V contents, the diffraction peaks of TiSiN/TaVN nanomultilayers were shifted to larger angles. Paralleling to the growth direction of TiSiN/TaVN nanomultilayers, an alternating stress fields are generated to enhance their strength. The hardness and elastic modulus of the nanomultilayers firstly increases and then decreases and friction coefficient firstly decreases and then increases with increasing of V contents. TiSiN/TaVN nanomultilayer with 15 at.% V content indicates the maximum hardness of 27.23GPa, the maximum elastic modulus of 280.96GPa and the highest resistance against plastic deformation. TiSiN/TaVN nanomultilayer with 15 at.% V content has minimum friction coefficient of 0.16 because Magnéli phase oxide V2O5 is formed during the reciprocating sliding friction process and H3/E2 of TiSiN/TaVN nanomultilayer with 15at.% V content is highest.
Safety Study Based on the Aging Mechanism of Retired Lithium Batteries
Authors: Zhang Taiyang , Shi Qian , Huang Xian’an , Zhang Chijian
Published: April 2023

Aiming at the problem of battery aging and capacity change during the charging and discharging cycle of decommissioned ternary lithium batteries, it is proposed to study lithium batteries from two different perspectives: macro and micro. Select the appropriate external characteristic parameters to carry out a large number of charge and discharge cycle experiments with different magnifications for the decommissioned ternary lithium battery, and observe the capacity and internal resistance of the lithium battery from a macroscopic perspective. For the battery disassembly experiment, the angle analyzes the changes in the internal material of the battery. The results show that the experimental verification of decommissioned lithium batteries can accurately analyze the reasons affecting battery aging and capacity change, so as to reduce the safety hazards of cascade use of batteries and extend the service life of batteries to provide data guidance and suggestions.
Preparation and Ferroelectric Properties of Ba(1-x-y)CaxSryTiO3 Nanotubes
Authors: Song Haibo , Sun Yanan , Xue Ridong , Yu Tianyi , Deng Xiangyun
Published: April 2023

In this paper, Ba(1-x-y)CaxSryTiO3 nanotubes with different doping concentrations were prepared by hydrothermal synthesis, and then their micro morphology, crystal structure, and ferroelectric properties were analyzed by SU8010 scanning electron microscope, D/MAX-2500 X-ray diffraction tester, and TF2000. It is found that the barium titanate nanotubes co doped with Ca and Sr have obvious tubular structure. With the increase of doping concentration, the nanotube diameter becomes smaller, the tube wall becomes thicker, and the ferroelectric properties of the samples increase first and then decrease. When 0.002mol/L Ca(CH3COO)2 and 0.002mol/L Sr(CH3COO)2 are doped, the maximum residual polarization intensity of Ba(1-x-y)CaxSryTiO3 is 0.097µC/cm2. At this time, there is a clear hysteresis loop image, and the ferroelectric performance is the best.
Study on V2O5 Nanoribbon Electrode Material
Authors: Wang Xinwei , Zhai Xuejie , Jiao Yanxia , Lv Pai , Wang Shunhua , Chi Junhong
Published: April 2023

V2O5 nanoribbon prepared by simple hydrothermal method has uniform dispersion and smooth surface. The width of nanoribbon is about 50 nm, the thickness is about 20 nm, and the length varies from 100 nm to 200 nm to 10 μm. By researching the electrochemical performance of V2O5 nanoribbon and exploring the influence of the type and concentration of electrolyte on the electrochemical performance, it is found that the electrochemical performance of V2O5 nanoribbon is the best in 0.5 mol·L−1 LiNO3 solution, and the specific capacitance of the material is 370 F·g−1(0.5 A·g−1).
Latest Progress of Mechanical Properties of Geopolymer Concrete at Elevated Temperature
Authors: Zhu Lina , Zha Xiaoxiong
Published: April 2023

In order to alleviate the environmental pollution and energy consumption problems caused by ordinary Portland cement, geopolymer came into being as a new type of green building material. The special three-dimensional mesh structure of geopolymer concrete makes it show excellent durability under fire, so it has been deeply studied by many scholars. This paper mainly expounds the research results of the basic static properties of inorganic geopolymer concrete at high temperature from the following four aspects: compressive strength, tensile strength, modulus of elasticity and stress-strain relationship. Due to the obvious differences in the mechanical and structural properties of geopolymer concrete in terms of raw materials, mix ratio, curing temperature, etc. There is no corresponding material and structural design specification for geopolymer concrete and it needs more incisive research before it applies to engineering construction.
Optimization Method of Acoustic Filter Structures Composed of Helmholtz Resonators Based on Genetic Algorithm
Authors: Lv Chenghao , Wang Xiaoming , Mei Yulin
Published: April 2023

This paper constructs an iteration method based on Genetic Algorithm to optimize the acoustic filter structure comprising Helmholtz resonators, providing a new approach to optimize the low-frequency filtering performance of the acoustic structure under the constraint of keeping the resonator volume unchanged. First, acoustic-electrical analogy is used to design a fifth-order Chebyshev type II acoustic filter structure, which comprises two rectangular Helmholtz resonators; second, an iteration method is constructed based on Genetic Algorithm to optimize the shape of Helmholtz resonator under the constraint of keeping the resonator volume unchanged; finally, an optimal acoustic filter structure is obtained by implementing the iteration procedure to design shapes of the two Helmholtz resonators. The simulation results show that, compared with the original rectangular Helmholtz resonator, the optimal Helmholtz resonator has a reduction of about 10% in the resonant frequency and an obvious shift of the transmission loss curve towards low frequencies; the optimal acoustic filter structure has an effective attenuation frequency range of 84-232Hz, showing a significantly improved low-frequency filtering performance, verifying feasibility and effectiveness of the iteration optimization based on Genetic Algorithm.
Fluorescence Characteristics Analysis of Rodamine B
Authors: Ma Yongzhong
Published: April 2023

In this paper, the fluorescence characteristics of rodamine B essence under different concentration, different solvent, different PH and different excitation time were studied, and the influence of these factors on the fluorescence spectrum of rodamine B essence was analyzed. The results showed that when the concentration of basic rose essence was less than 1×10-4g/L, the fluorescence intensity was positively correlated with the concentration. When the concentration of basic rose essence was greater than 4×10-3g/L, the fluorescence intensity increased first and then decreased with the increase of basic rose essence. When the dielectric constant of the solvent increases, the fluorescence intensity of the solution increases. When PH is 1 ~ 2, the fluorescence intensity increases gradually. At 3, the fluorescence intensity remained unchanged.
Study on Factors Affecting the Compressive and Flexural Strength of the Geopolymer Paste using the Wet Mixing Method
Authors: Wang Kai , Chen Dejing , Gao Yuting
Published: April 2023

The paper investigates the 28 days compressive & flexural strength of the fifty-seven geopolymer paste specimens using the wet mixing method. The completely decomposed granite (CDG), combined with the slag were chosen as the sources of silicon and aluminum components. Types of the alkali solutions, the slag content, modulus and concentration of the alkali solutions, along with the liquid-solid ratio, were chosen as the variables. Influences of the parameters on the mechanical behavior of the geopolymer paste are discussed in the paper.
Study on Crack Resistance of C35 Limestone Powder Concrete
Authors: Wang Yige , He Tao , Rong Guocheng , Song Putao , Xia Jingliang , Leng Faguang
Published: April 2023

C35 pier concrete was prepared with natural limestone powder and fly ash, and the effect of the proportion of limestone powder and fly ash on hydration heat of composite cementitious material system was studied At the same time, the effects of different proportions of natural limestone powder and fly ash on adiabatic temperature rise, early shrinkage, drying shrinkage and early cracking of concrete were studied. The results show that the hydration heat of composite cementitious material system can be reduced by adding natural limestone powder and fly ash, the early shrinkage and dry shrinkage of concrete can be reduced, and the cracking of concrete can be reduced. On the contrary, when natural limestone powder and fly ash replace cement by 20%, 10% mass ratio, C35 concrete has the best indexes and better crack resistance.
Recrystallization Behavior of Specially Oriented Grains during Dynamic Softening of Powder Superalloys
Authors: Zhang Mincong , Li Kai , HaiLin
Published: April 2023

By analyzing the degree of grain deformation of FGH96 alloy under different plastic deformation process parameters, as well as the relative frequency and distribution characteristics of recrystallized core and grain boundaries with different orientation differences, comprehensively considering the evolution law of grains of different sizes, the relationship between grain boundary characteristics and grain boundaries is studied. The correlation and evolution law between the nucleation mechanism of recrystallized grains, the growth characteristics of recrystallized cores, and related dynamic softening mechanisms, combined with the change trend of grain orientation during deformation, for the special orientation grains generated during deformation. Granules and their recrystallization behavior characteristics were analyzed.
Chlorine Induced In-Situ Growth of TiO2 Nanoparticles on PVC Nano Fibers
Authors: Peng Wei , Wo Zihao , Shi Chaofan , Ma Hua , Su Yier , Zhou Dongshan , Zhang Xiwen
Published: April 2023

PVC-TiO2-DBD nanocomposites were synthesized via combined approaches of electrospinning, H2 plasma treatment and hydrothermal reaction. The spinning solution composition and the amount of PVC were investigated and optimized in order to obtain membranes with uniform structure and high chemical activity. It was found that TiO2 NPs were distributed homogeneously on the surface of the PVC fibers. Chemical bonds such as Ti-Cl and C-O-Ti bonds were formed to tightly immobilize the TiO2 NPs on the PVC surface. The effect of H2 plasma treatment on the surface of the PVC membranes was studied. Meanwhile, using ABS and PS as substrates, the influence of various groups, including chlorine bonds, C=C double bonds, cyano and phenyl groups on the possible promotion mechanism of different chemical bonds for the TiO2 deposition was also studied. Possible mechanisms for the enhancement of the deposition of TiO2 were given.
Preparation of Photoresponsive Nanosilica Powder
Authors: Qiu Xirong , Yan Xiaowei , Wang Zhimin , Zhang Cuimin , Sun Leyi , Bai Shengxin , Liu Zhimin , Xu Anhou
Published: April 2023

In order to obtain photoresponsive silicon dioxide nanopowders, fluoropolymer/SiO2 composite microspheres were prepared with a thiol-terminated fluoropolymer and with SiO2 microspheres grafted by acrylate via the thiol-ene click reaction; then, photoresponsive SiO2 nanopowders were synthesized by grafting azobenzene monomers on the surface of the SiO2 composite microspheres by esterification. The fluoropolymer and SiO2 composite microspheres were characterized via proton nuclear magnetic resonance, scanning electron microscopy, contact angle tests, dynamic light scattering, and UV-Vis absorption spectroscopy. The surface of the coating prepared using SiO2 nanopowders exhibited a high contact angle up to 130.9°. When the surface was irradiated with UV light, the contact angle decreased to 104.1°. Reversible changes in the surface wettability could be realized under the alternate irradiation of ultraviolet and visible light, thus achieving excellent photoresponsiveness.
High-entropy (Oxy)hydroxide Prepared by Electrodeposition for Highly Efficient OER in Alkaline Medium
Authors: He Lixiang , Wang Ni , Hu Wencheng
Published: April 2023

With the development of the economy and society, energy shortage and environmental pollution are increasingly in the spotlight. Electrolytic water to hydrogen technology is considered to be the best way to produce green hydrogen. However, the slow thermodynamic/kinetic limitations make it difficult to scale application due to an anodic oxygen evolution reaction (OER) involving four electrons. Recently, transition metal-based materials become popular research subjects because properties of abundant reserve and low cost. Fortunately, the performances for water splitting are surprising compared to some noble metal-based materials which means these materials have huge potential for practical application in reality. The transition metal (oxy)hydroxides are confirmed to be a category of promising electrocatalysts for OER. To improve the activity of catalysts, many effective strategies (including defects engineering, vacancy engineering, interface engineering, high-entropy effect, etc.) are adopted to modulate the electronic structure and enrich active site density. In this work, we have successfully synthesized high-entropy transition metal (oxy)hydroxides by one-step electrodeposition for water oxidation. The results obtained confirmed the high-entropy effect results in high intrinsic activity and high stability for electrochemical water oxidation.
Fabrication and Properties Detection of PLA-CNTs Hybrid Film Based on a Phase Inversion Method
Authors: Yu Kai , Hu Xueyan , Su Ya , Xu Jiahong , Liu Fangyu , Kang Yue , Song Kedong
Published: April 2023

Carbon-based nanomaterials have been extensively studied as scaffolds for neural tissue regeneration. In particularly, carbon nanotubes (CNTs), was most widely applied in neural tissue engineering due to their excellent electrical conductivity and good biocompatibility. In this study, the CNTs were introduced into the pure PLA film, to optimize the function of PLA film for further application. The PLA-CNTs film with CNTs content of 0%, 0.2%, 0.4% and 0.6% were prepared by a phase inversion method, respectively. Following this, the morphology and mechanical properties of the films were both evaluated. The results illustrated the CNTs were uniformly dispersed on the film surface and increased the surface roughness. The film had microporous structure on the cross section, which was not effect by the CNTs. Meanwhile, the critical tensile stress of the film increased from 14.0±3Mpa to 19.7 ±2Mpa, but the elastic modulus of PLA-CNTs hybrid film was no significantly changes. It is a preliminary study about fabrication and characterization of PLA-CNTs film.
Preparation and Characterization of a Novel Tissue-Engineered Blood Vessel of dECM/CS/Gel Bilayer Scaffolds
Authors: Du Jing , Liu Jiaqi , Suo Qiang , Ji Yunfang , Wang Yujie , Kang Yue , Li Xiangqin , Song Kedong
Published: April 2023

At present, decellularized extracellular matrix (dECM) has become a popular research material worldwide due to its good biocompatibility in the research of small-diameter tissue engineering blood vessels (diameter ≤6mm). In this study, the cells of porcine coronary artery were removed by acellular method to obtain dECM, which was coated with chitosan (CS)/gelatin (Gel) mixed hydrogels with different concentrations to bionic the natural blood vessel’s multilayer structure. The mechanical properties, microstructure, and biocompatibility of scaffolds were characterized. The experiment result showed that the bilayer scaffolds with different proportions were successfully constructed by this method, and the outer layers and inner layers of scaffolds were closely connected, and the pores were evenly distributed. The critical tension and elastic modulus of the five scaffolds showed no significant difference, and all scaffolds had good biocompatibility.
Research of Forming Microstructure of Copper/Graphite Composite Coating Prepared Based on Laser Micro-cladding
Authors: He Hongjun , Su Shaoxing , Dong Tianyuan , Song Wuyu , Lang Wenchang , Wei Xinlei
Published: April 2023

In order to further study the forming process and evolution mechanism of new copper / graphite composite coating based on laser microcladding technology, three groups of alloy powder materials with different proportions were set up, and the 1500W fiber laser was used to prepare micro-cladding coatings on 45# steel substrates. According to the known macroscopic morphology, four groups of cladding samples with uniform, smooth and dense surface were selected for analysis, the microstructure characteristics, element distribution and growth morphology, and the causes of microstructure defects were qualitatively and quantitatively analyzed by means of the metallographic test, SEM and EDS.On this basis, the relationship between the interfacial reaction mode affected the forming microstructure of micro-cladding coating and the flow behavior of molten pool was obtained, which can be used as a reference for the optimization and regulation of the process.
Outgassing Rates and Compositions of the Released Gases from Optical Fiber Panel and Photocathode Glass Used for Low-light-level Image Intensifiers
Authors: Guo Xin , Pang Yan , Deng Ningkang , Yuan Yuan , Hu Wenbo , Bu Renan
Published: April 2023

To analyze the vacuum failure mechanism of low-light-level image intensifiers in depth, the outgassing rates and compositions of the released gases from optical fiber panel and photocathode glass used for the image intensifiers were investigated by static pressure-rising method and residual gas analysis. The investigation results show that the outgassing rate of the optical fiber panel at a baking temperature of 150°C is only about one order of magnitude higher than that at 23°C, while the outgassing rate of the photocathode glass at 150°C is about two orders of magnitude higher than that at 23°C. As the static accumulation time of gas releasing extends, the outgassing rate of the optical fiber panel linearly increases at 23°C, and it remains basically unchanged at 150°C, while for the photocathode glass, its outgassing rate increases rapidly firstly and then tends to be stable gradually both at 23°C and 150°C. The gas compositions released from the optical fiber panel and photocathode glass at 23°C mainly include H2O, H2, N2/CO and CO2. After experiencing the vacuum baking at 150°C, the releasing ratio of H2O gas from the optical fiber panel decreased just slightly, which indicates that the vacuum baking degassing for the photocathode glass is relatively difficult; by contrast, the releasing ratio of H2O gas from the photocathode glass significantly decreased, and that of H2 gas obviously increased. These results can provide experimental bases for further optimizing the component materials and fabrication process of low-light-level image intensifiers.
Crystal Structure Analysis of Different Flame Retardant Copolymers
Authors: He Feng , Liu Qinghua
Published: April 2023

In this paper, through the DSC rising and cooling scanning and non-isothermal crystallization tests of different flame retardant copolymers, the crystallization process of four types of copolymers formed by adding different flame retardants such as CEPPA, DDP, Carbon-dots (gCDs), and MOF materials was studied. Also, the crystallization kinetics and crystal structure were explored. The results showed that the flame retardant effect of the flame retardant copolymer was improved after adding gCDs. The subcooling temperature (ΔTmc) values of MOF material and CEPPA were both higher than those of the DDP flame retardant copolymer after the addition of carbon dots, indicating that the introduction of the carbon-dots material made crystallisation easier. With the increase of carbon dot content, the value first increases and then decreases, indicating that the crystallization is the easiest when the content is 1%, and 1% gCDs+8% DDP has a higher crystallization ability. Pure DDP has the highest mc values, which also shows good spinnability. Also, the cooling rate strongly influences the crystallisation process, with crystallisation being more rapid when the crystallisation rate is higher. Also, the cooling rate strongly influence the crystallisation process, with crystallisation being more rapid when the crystallisation rate is higher.
Preparation of the Acenaphthene Phenyl Silicone Oil with Vinyl and Its Effent on Silicone Rubber Vulcanized at Room Temperature
Authors: He Xiaofeng , Guo Fuqiang , Ge Tiejun , Tang Kaihong , Shi Shengnan , Geng Maofu
Published: April 2023

The acenaphthene phenyl silicone oil with vinyl (AEPSV) was synthesized by Diels-Alder reaction with polyvinyl siloxane (SV) and acenaphthylene cyclopentadienone (AECPO). The structure was characterized by means of FT-IR and1H-NMR. Then added its into the silicone rubber as the heat-resistant additive. And the influence of content on the heat resistant and mechanical properties of silicone rubber were studied. The results showed that when the mass fraction of heat-resistant additiv was 9%, the initial degradation temperature of silicone rubber was 431.85°C.
Optimization Design and Fatigue Lifetime Analysis for Elastic Wheel of Low-floor Trams Using in Urban Rail Transit
Authors: Zhao Rongguo , Ye Duheng , Lin Sheng , Hu Weihui , Xiao Xianglong , Liu Yonglin , Mohammad Zaheer
Published: April 2023

Elastic wheel is an important component of the low floor tram using in urban rail transit, so it is of significance to optimize its structure and predict its service lifetime. Firstly, the fatigue characteristics of rubber material are studied based on the crack energy theory, and a finite element model of an elastic wheel for fatigue lifetime prediction is constructed. The numerical simulation results show that the fatigue lifetime of such a elastic wheel does not match with the expected one. Secondly, based on the orthogonal numerical test and the Sobol model, an improved sensitivity analysis method is proposed. Taking the minimum strain as an optimization objective, and selecting the structural parameters determined by the sensitivity analysis method as the design variables, the second-order response surface model is established, and the multi-island genetic algorithm is used to carry out the single objective and multi-factor optimization design of the rubber bodies of elastic wheel under the condition of stiffness constraint. The simulation results of the elastic wheel show that the fatigue lifetime of the optimized structure is 30% higher than that of the original one. Finally, the optimized elastic wheel is tested, and the results show that the stiffness coefficient, and the fatigue lifetime as well, are all satisfy with the design requirements.
Lightweight Optimization Design and Fatigue Lifetime Analysis for Anti-rolling Torsion Bar of Rail Vehicle
Authors: Zhao Rongguo , Liu Yonglin , Liu Wensong , Ye Duheng , Tang Lianyi , Xu Lingpeng , Mohammad Zaheer
Published: April 2023

Based on the fatigue strength assessment method in the FKM standard, the lightweight design of a type of anti-rolling torsion bar is studied by using the finite element method. Firstly, the finite element model of the torsion bar structure is constructed by using the Creo software and the HyperMesh software, and then the finite element analysis is carried out by using the ABAQUS software. The numerical simulation results indicate that under the condition of ultimate load 29.2kN, the static strength, anti-rolling stiffness and fatigue strength of the torsion bar are all satisfy with the design requirements. Secondly, the orthogonal numerical test method is utilized to investigate the influence of geometric parameters on the anti-rolling stiffness and Factor of Strength (FOS) value of the torsion bar. Taking the structural geometric parameters as variables and the FOS value as the objective function, a second-order response surface model is established. The single objective and multi-factor optimization design for the torsion bar under the condition of stiffness constraint is conducted by using the Isight software and multi-island genetic algorithm. The results show that, comparing with the original structure, the weight of the optimized structure is reduced by 20.89%, and the static and dynamic strength, and anti-rolling stiffness of the optimized structure are match with the design requirements. Finally, the static and dynamic strength tests for the optimized torsion bar are individually operated at the ultimate load and under two-stage cyclic loading with amplitude 18.0kN and 29.2kN. the results show that the calculated stiffness coefficient is consistent with the test one, and the service lifetime of the torsion bar is satisfy with the design requirement.
Simulation of Temperature Field in FSW of 6061T6 Aluminum Alloy IGBT Liquid Cooled Radiator Panel
Authors: Chen Xinghui , Zhang Hongshen , Huang Gan
Published: April 2023

Heat input and temperature field distribution in the welding process are crucial to welding quality. The parameters in the FSW process are optimized to study the influence of the temperature field on a car Insulated Gate Bipolar Transistor(IGBT) liquid cooled radiator panel 6061T6 aluminum alloy under friction stir welding. This paper established the liquid cooled radiator panel with friction stir welding fully coupled thermo-mechanical model, and explored the thermal physical parameters of 6061T6 aluminum alloy based on JMATPRO. Then, the temperature field distribution rules of friction stir welding at the inlet of liquid cooling plate and the weld joint under different welding time are explored by using ABAQUS. The effects of different rotational and welding speeds on the temperature field of the welded joint are also studied. Results show that most of the heat in the FSW process is generated by the shaft shoulder of the tool, and the heat at the welding position is a conical shape. Under the assumption that other technological parameters remain unchanged, the rotational speed of the pin is the most important factor affecting the temperature field of the FSW process.
Research and Improvement of Heat Transfer Performance of Plate and Shell Evaporator
Authors: Huang Jiarui , Zou Tonghua , Liu Zhe
Published: April 2023

Evaporator plays a key role in indirect refrigeration system, so improving the efficiency of evaporator is of great significance to improve the overall performance of refrigeration system. For the plate and shell evaporator, the reliability of the model is proved by numerical simulation of the existing evaporator and comparison with the experiment. An improved scheme is proposed for the existing evaporator, and the improved model is simulated and analyzed. The result shows that compared with the previous model, the improved model improves the heat exchange efficiency, reduces the pressure drop, and improves the overall efficiency of the evaporator.
Fabrication and Toxicity Assessments of A Novel Antibacterial Polyvinyl Alcohol/Polyionic Liquid Hybrid Membrane
Authors: Wang Hao , Hu Xueyan , Su Ya , Xu Jie , Fang Huan , Liu Jiaqi , Kang Yue , Li Xiangqin , Chen Zhen , Song Kedong
Published: April 2023

Poly ionic liquids (PILs) have become important choices as antibacterial agents because of their excellent biological properties and abundant species. Development of new antibacterial materials with PIL has been a feasible and popular research topic. In this paper, the Polyvinyl Alcohol/Polyionic Liquid (PVA-PIL) hybrid membranes were fabricated by vacuum drying method. Poly (1-Vinyl-3-butylimidazolium bromide) (PIL1) and poly (1-Vinyl-3-butylimidazolium bromide)-poly (butyl acrylate) (PIL2) were selected and tested as the main components of bacteriostatic agents. The antibacterial properties of the PVA-PIL hybrid membranes against bacteria E. coli and S. aureus were tested by the disc method. Meanwhile, the cytotoxicities of hybrid membranes were evaluated against mouse fibroblast (L929) by fluorescent staining experiment. M2 showed excellent antibacterial properties which could not be found on M3. Furthermore, all PVA-PIL membranes exhibited favorable cytocompatibilities. These properties make M2 a possible candidate for wound dressing.
Technical Appraisal Method of Circuit Breaker Material Evidence in Fire
Authors: Wang Liantie , Li Dandan , Guo Chen
Published: April 2023

Circuit breaker is an important electrical control on and off in the electrical line, which refers to the switch device that can close, load and break the current under normal loop conditions, and can close, load and break the current under abnormal loop conditions in the specified time. Circuit breakers are divided into high voltage circuit breakers and low voltage circuit breakers according to their range of use. Low voltage circuit breakers are common to molded case circuit breakers. Play a protective role in the safety of electrical lines and electrical appliances. When a fire occurs, the action of the circuit breaker plays a vital role in the occurrence and development of the fire. Therefore, the circuit breaker is an important material evidence in the investigation of the cause of electrical fire, and it will play an irreplaceable role in the investigation of the cause. In particular, the plastic case circuit breaker is the most commonly used type in life. The plastic case circuit breaker extracted from the fire scene, according to the appearance characteristics or internal structure characteristics, identify its working state in a period of time before and after the fire, and can judge the relationship between the physical evidence and the cause of fire.
Application of Secondary Short Circuit Fuse Mark in Fire Cause Investigation
Authors: Wang Liantie , Mo Yunfei , Meng Qingshan
Published: April 2023

Metallographic analysis technology holds an important place in the fire material evidence identification, especially in the cause of the electrical fire scene investigation process, indispensable metallographic method, through the analysis of the microstructure of metal material evidence, can judge the melting properties of material evidence, namely the formation of physical evidence logic relationship with the occurrence of fire in time, Thus provide the most direct evidence for the fire scene investigation. There are many kinds of fusion marks extracted from fire scene, common ones are fire fusion mark, primary short circuit fusion mark, secondary short circuit fusion mark, etc. [1]. The relationship between the formation of secondary short circuit fuse mark and the electrical circuit is complicated, and its characteristics are different from those of fire fuse mark and primary short circuit fuse mark.
Experimental Study on the Chemical Resistance of Polyaroxydiazole Fiber
Authors: Niu Huirong , Mao Ning
Published: April 2023

Polyarylene oxadiazole fiber (POD) is a kind of fiber commonly used in high temperature resistant filter materials. It is used in industrial filter screens. In order to study its chemical corrosion resistance, this paper uses different mass fractions of sulfuric acid, nitric acid, sodium hydroxide and ammonia solution is used to treat the POD fibers for different times. By characterizing the mechanical properties of the treated fiber, it intuitively reflects the acid and alkali resistance of the POD fibers. The results show that the strength retention rate of POD fibers is 38% when treated with 50% sulfuric acid for 72 hours; the strength retention rate is 36% when treated with 60% nitric acid for 72 hours; the strength retention rate is 77% when treated with 30% sodium hydroxide for 72 hours and after 72 hours of treatment with 20% ammonia water, its strength retention rate is 79%; the alkali resistance of POD fibers is better than the acid resistance.
Study on Microstructure and Properties of Thermal Barrier Coating for Gas Turbine
Authors: Sui Yongfeng , Liao Xiaolin , Liu Zhonghua , Tu Yao , Yu Peijiong , Chu Peng
Published: April 2023

Thermal barrier coating (TBC), which can protect the metallic components from hot gas, is one of the core technologies to achieve the development goal of higher thermal efficiency and lower emission for gas turbine. A double-coat TBC was prepared on the Mar M247 substrate of turbine blade for gas turbine which consisted of a CoNiCrAlY bond coat(BC) was prepared by high velocity oxygen fuel(HVOF) and a ZrO2-8Y2O3(8YSZ) top coat(TC) was prepared by atmospheric plasma spraying (APS).The microstructure of the TBC was analyzed by optical microscope(OM) and scanning electron microscope(SEM), and the thermal insulation and thermal shock resistance of the TBC were investigated. The results show that the homogeneous and fine microstructure in TBC is obtained,the interfacial bonding between the top coat and the bond coat, between the bond coat and the substrate is well. The thermal insulation temperature can reach 156°C,under the condition of test temperature of 1150°C and cooling air flow of 4 m3/h. And the thermal shock resistance is greater than 100 cycles at the test condition of 1050 °C.
Synthesis and Electrochemical Properties of SnO2/C Nanocomposites
Authors: Li Lin , Zheng Wei , Cheng Jinsong , Zhao Rongfei
Published: April 2023

The SnO2/C nanocomposites were prepared through a facile approach combining sol-gel synthesis with thermal reduction. The XRD, TG, (HR-) TEM, and electrochemical performance tests were used to study the relevance between the physical character and electrochemical properties of the electrode material. As the anode material, the results show that the SnO2/C nanocomposites delivered excellent lithium storage properties (539 mAh g–1 of 100th), compared with the bare SnO2 nanoparticles. It is demonstrated that the preparation of SnO2/C nanocomposites structured can effectively alleviate the particle pulverization caused by volume expansion, effectively shorten the diffusion distance of lithium ions, prevents the aggregation of SnO2 with the carbon layer, and improve the cycle stability of the electrode. Meanwhile, the incorporation of the SnO2 particles suppressed the stack of carbon layer.
SnS-RGO Hybrid Nanosheets as High Performance Flexible Photodetectors and Visible-Light Photocatalysts
Authors: Li Ang , Zhuo Renfu , Tang Xiaoli , Wang Jun , Yan De , Men Xuehu , Geng Baisong , Wu Zhiguo , Yan Pengxun , Zhang Guangàn
Published: April 2023

A straightforward solvothermal technique was used to create tin monosulfide (SnS) nanosheets that were reduced graphene oxide (RGO) bonded. On the folded RGO surface, it was discovered that the 2D SnS nanosheets had several layers that were evenly distributed. When exposed to visible light, a flexible photodetector made of PET substrate exhibits a 1.4 mA W−1 optical response, 3.5 × 107 Jones detection rate, and quick rise and fall times. (τ
rise = τ
decay = 0.08 s). When exposed to visible light, the methylene blue’s (MB) photocatalytic breakdown was used to test the photocatalytic performance of the synthesized SnS-RGO hybrid nanosheets. The fact that almost all of the MB dissolved in under one hour suggested that SnS-RGO nanosheets make promising high-performance photocatalysts.
Strengthening and Toughening Technology of Epoxy Resin
Authors: Wei Huazhen , Wang Danyong , Xing Wenfang
Published: April 2023

Epoxy resin materials have excellent processability, adhesion, corrosion resistance, electrical insulation, mechanical properties, heat resistance and other properties. At present, they are widely used in weapons, aviation, aerospace, high-temperature adhesives and many other fields. However, epoxy resin has the defects of brittleness, low flexibility, weak impact resistance, poor peel resistance and low heat resistance in the process of use, especially in high-end fields such as weapons, the upper limit temperature is not high, The problems of high brittleness and easy premature cracking exposed in low temperature environment limit the deeper use of epoxy resin materials. This paper analyzes and discusses the advantages and disadvantages of some mainstream epoxy resin modification technologies, and prospects the next research trend, so as to provide reference for further research on strengthening and toughening epoxy resin in the future.
Finite Element Structural Simulation of Connecting Rod
Authors: Jia Huamin , Li Shuhu
Published: April 2023

As an important bearing structure of maglev train, the connecting rod has high requirements for material performance. In this paper, according to the structural bearing capacity of the connecting rod, the finite element methodwas used to calculate and analyze the structure of the composite connecting rod and the aluminum alloy connecting rod under two working conditions, so as to determine the advantages of the composite connecting rod in mechanical properties and provide theoretical support for the design of the composite connecting rod.
Preparation, Properties and Application of Homogeneous Polypropylene Cation Exchange Membrane
Authors: Jia Yifan , Tao Ran , Gao Degui , Yang Xuhong , Zhu Xinsheng
Published: April 2023

Electrodeionisation (EDI) is one of the most important methods for the separation and purification of heavy metal ions from wastewaters. Acrylic acid (AA) and butyl acrylate (BA) were grafted onto polypropylene nonwoven to prepare cation exchange membranes, which were used for EDI treatment of simulated Cu(II) wastewater. The effects of the ratio of two monomers, initiator and crosslinker on the microstructure, mechanical and electrochemical properties of the resultant homogeneous polypropylene membranes were investigated. The experimental results show that at the conditions of AA: BA = 2:1, BPO 3.75%, and PETA 7%, a grafting rate of over 240% is achieved with high IEC, low water permeability and good mechanical properties. However, too much crosslinking makes area resistance high. Compared to commercially available heterogeneous membrane, the resultant membranes have better Cu(II) separation, longer service life but lower current efficiency.