bluuebunny/crossref_metadata_2025 huggingface dataset:
A review on recent advances in g-C3N4-MXene nanocomposites for photocatalytic applications
Authors: Subha N , Nagappagari Lakshmana Reddy , Ravi Sankar A
Published: September 2024

The solutions for environmental remediation and renewable energy generation have intensified the exploration of efficient photocatalytic materials. Recently, the composites of g-C3N4 and MXene have gained considerable interest for their potential applications in photocatalysis. In the g-C3N4-MXene composite, the g-C3N4 possesses unique physical, chemical, and optical properties to increase visible light absorption. At the same time, MXene improves conductivity, adsorption of reactant molecules or the active sites, and charge transfer properties. Combining the unique physico-chemical properties of MXene and g-C3N4, the resulting composite exhibits superior photo-responsive behavior and is critical in photocatalytic reactions. Furthermore, the g-C3N4-MXene composite exhibits stability and recyclability, making it a promising candidate for sustainable and scalable photocatalytic material in environmental remediation. This review offers an in-depth analysis of the development and design of g-C3N4-MXene composites through diverse synthesis procedures and a comprehensive analysis of their application in carbon dioxide (CO2) reduction, photocatalytic degradation, water splitting processes, mainly hydrogen (H2) generation, H2O2 production, N2 fixation, and NO
x
removal. The charge transfer mechanism of g-C3N4-MXene composite for photocatalytic application has also been discussed. This review provides insights into the photocatalytic capabilities of g-C3N4-MXene composites, showing their potential to address current environmental challenges and establish a robust foundation for sustainable energy conversion technologies.
Recent advances in scanning electrochemical microscopy for energy applications
Authors: Wang Qi , Tang Qianlin , Li Peipei , Bai Xiaoxia
Published: September 2024

Scanning electrochemical microscopy (SECM) is a scanning probe technique capable of imaging substrate topography and measuring the local electrochemical reactivity of interfaces. Since introduced by Allen J. Bard and co-workers in 1989, it has expanded into a wide variety of fields, such as nanomaterial characterization, energy, kinetics, electrocatalysis, metal anti-corrosion, biology and instrumental development. SECM uses an ultra-microelectrode as the probe to record redox current during probe scanning across sample surfaces to obtain local topography and electrochemical reactivity of samples. Specifically, three main topics are reviewed and discussed: (1) the working principles and operating modes of SECM; (2) the recent developments in the application of SECM in energy science, including solar cell, rechargeable batteries, fuel cells and supercapacitors, with an emphasis on the last five years (2019–2023); (3) the perspectives and outlook of SECM in various energy devices. We anticipate that a wider adoption of SECM by the energy community will allow for the operando characterization of many types of reactions, and hold the potential to provide new insights into the structure/activity and composition/activity relationships.
Coherent random fiber laser emission from CdSe/ZnS quantum dots
Authors: Ye Lihua , Cheng Zhixiang , Zhang Ziang , Hong Shaoqiang , Zhao Qing
Published: September 2024

We experimentally demonstrate the coherent random laser emission by combining CdSe/ZnS colloidal quantum dots with hollow optical fiber. Through the localized surface plasmon resonance induced by Ag nanoparticles (NPs), well-distinguished discrete spikes are observed from the Ag modified hollow fiber loaded with CdSe/ZnS QDs solution. In addition, coherent random laser action with low threshold is also realized in the hollow optical fiber filled with high packing-density CdSe/ZnS QDs even if the Ag NPs is not introduced. The self-assembled clusters of CdSe/ZnS QDs serve as the optical gain media as well as the strong scattering centers. The angle measurement experiments show that the directional emission of random laser can be adjusted by using different pumping manners. This facile, inexpensive, low pump threshold random laser could be widely used in photonic devices and display imaging.
A cubic perovskite fluoride anode with the surface conversion reactions dominated mechanism for advanced lithium-ion batteries
Authors: Ju Zhicheng , Feng Qilin , Wang Xinfeng , Zhuang Quanchao , Shi Yueli , Jiang Jiangmin
Published: September 2024

Perovskite fluorides are attractive anode materials for lithium-ion batteries (LIBs) because of their three-dimensional diffusion channels and robust structures, which are advantageous for the rapid transmission of lithium ions. Unfortunately, the wide band gap results in poor electronic conductivity, which limits their further development and application. Herein, the cubic perovskite iron fluoride (KFeF3, KFF) nanocrystals (∼100 nm) are synthesized by a one-step solvothermal strategy. Thanks to the good electrical conductivity of carbon nanotubes (CNTs), the overall electrochemical performance of composite anode material (KFF-CNTs) has been significantly improved. In particular, the KFF-CNTs deliver a high specific capacity (363.8 mAh g−1), good rate performance (131.6 mAh g−1 at 3.2 A g−1), and superior cycle stability (500 cycles). Note that the surface conversion reactions play a dominant role in the electrochemical process of KFF-CNTs, together with the stable octahedral perovskite structure and nanoscale particle sizes achieving high ion diffusion coefficients. Furthermore, the specific lithium storage mechanism of KFF has been explored by the distribution of relaxation times technology. This work opens up a new way for developing cubic perovskite fluorides as high-capacity and robust anode materials for LIBs.
Global and local feature extraction based on convolutional neural network residual learning for MR image denoising
Authors: Li Meng , Yun Juntong , Liu Dingxi , Jiang Daixiang , Xiong Hanlin , Jiang Du , Hu Shunbo , Liu Rong , Li Gongfa
Published: September 2024

Objective. Given the different noise distribution information of global and local magnetic resonance (MR) images, this study aims to extend the current work on convolutional neural networks that preserve global structure and local details in MR image denoising tasks. Approach. This study proposed a parallel and serial network for denoising 3D MR images, called 3D-PSNet. We use the residual depthwise separable convolution block to learn the local information of the feature map, reduce the network parameters, and thus improve the training speed and parameter efficiency. In addition, we consider the feature extraction of the global image and utilize residual dilated convolution to process the feature map to expand the receptive field of the network and avoid the loss of global information. Finally, we combine both of them to form a parallel network. What’s more, we integrate reinforced residual convolution blocks with dense connections to form serial network branches, which can remove redundant information and refine features to further obtain accurate noise information. Main results. The peak signal-to-noise ratio, structural similarity index measure, and root mean square error metrics of 3D-PSNet are as high as 47.79%, 99.81%, and 0.40%, respectively, achieving competitive denoising effect on three public datasets. The ablation experiments demonstrated the effectiveness of all the designed modules regarding all the evaluated metrics in both datasets. Significance. The proposed 3D-PSNet takes advantage of multi-scale receptive fields, local feature extraction and residual dense connections to more effectively restore the global structure and local fine features in MR images, and is expected to help doctors quickly and accurately diagnose patients’ conditions.
Enhancing bone scan image quality: an improved self-supervised denoising approach
Authors: Yie Si Young , Kang Seung Kwan , Gil Joonhyung , Hwang Donghwi , Choi Hongyoon , Kim Yu Kyeong , Paeng Jin Chul , Lee Jae Sung
Published: September 2024

Objective. Bone scans play an important role in skeletal lesion assessment, but gamma cameras exhibit challenges with low sensitivity and high noise levels. Deep learning (DL) has emerged as a promising solution to enhance image quality without increasing radiation exposure or scan time. However, existing self-supervised denoising methods, such as Noise2Noise (N2N), may introduce deviations from the clinical standard in bone scans. This study proposes an improved self-supervised denoising technique to minimize discrepancies between DL-based denoising and full scan images. Approach. Retrospective analysis of 351 whole-body bone scan data sets was conducted. In this study, we used N2N and Noise2FullCount (N2F) denoising models, along with an interpolated version of N2N (iN2N). Denoising networks were separately trained for each reduced scan time from 5 to 50%, and also trained for mixed training datasets, which include all shortened scans. We performed quantitative analysis and clinical evaluation by nuclear medicine experts. Main results. The denoising networks effectively generated images resembling full scans, with N2F revealing distinctive patterns for different scan times, N2N producing smooth textures with slight blurring, and iN2N closely mirroring full scan patterns. Quantitative analysis showed that denoising improved with longer input times and mixed count training outperformed fixed count training. Traditional denoising methods lagged behind DL-based denoising. N2N demonstrated limitations in long-scan images. Clinical evaluation favored N2N and iN2N in resolution, noise, blurriness, and findings, showcasing their potential for enhanced diagnostic performance in quarter-time scans. Significance. The improved self-supervised denoising technique presented in this study offers a viable solution to enhance bone scan image quality, minimizing deviations from clinical standards. The method’s effectiveness was demonstrated quantitatively and clinically, showing promise for quarter-time scans without compromising diagnostic performance. This approach holds potential for improving bone scan interpretations, aiding in more accurate clinical diagnoses.
CaviPlasma: parametric study of discharge parameters of high-throughput water plasma treatment technology in glow-like discharge regime
Authors: Čech J , Sťahel P , Prokeš L , Trunec D , Horňák R , Rudolf P , Maršálek B , Maršálková E , Lukeš P , Lavrikova A , Machala Z
Published: September 2024

AC discharge in a dense hydrodynamic cavitation cloud in water, called CaviPlasma, has been studied at different discharge parameters. CaviPlasma stands for cavitation and plasma, which are two coupled basic phenomena of the novel technology enabling very high throughput of plasma water processing compared to other current technologies. In this article, the diagnostics and the properties of CaviPlasma discharge are discussed based on optical and electric characterization of the discharge phenomena together with the physico-chemical characterization of the plasma-treated water. The so-called unbridged mode of CaviPlasma operation is described, where the discharge propagates from a metal electrode towards a liquid electrode at the collapsing end of the cavitation cloud. The production of H, O and OH species in the discharge was proven by optical emission spectroscopy. The formation of hydrogen peroxide (H2O2) in water was determined by chemical methods. The energy yield for H2O2 generation is as high as 9.6 g kWh−1 and the generation rate is up to 2.4 g h−1. The degradation of phenol admixture in water was also studied. The article covers a parametric study enabling the development of tailored applications.
Observation of quantum entanglement in top quark pair production in proton–proton collisions ats=13 TeV
Authors: CMS Collaboration The
Published: September 2024

Entanglement is an intrinsic property of quantum mechanics and is predicted to be exhibited in the particles produced at the Large Hadron Collider. A measurement of the extent of entanglement in top quark-antiquark (tt¯) events produced in proton–proton collisions at a center-of-mass energy of 13 TeV is performed with the data recorded by the CMS experiment at the CERN LHC in 2016, and corresponding to an integrated luminosity of 36.3 fb−1. The events are selected based on the presence of two leptons with opposite charges and high transverse momentum. An entanglement-sensitive observableDis derived from the top quark spin-dependent parts of thett¯production density matrix and measured in the region of thett¯production threshold. Values ofD<−1/3are evidence of entanglement andDis observed (expected) to be−0.480−0.029+0.026(−0.467−0.029+0.026) at the parton level. With an observed significance of 5.1 standard deviations with respect to the non-entangled hypothesis, this provides observation of quantum mechanical entanglement withintt¯pairs in this phase space. This measurement provides a new probe of quantum mechanics at the highest energies ever produced.
Observation of limit torus and catastrophe point in optomechanical systems
Authors: Liang Jing-Yu , Long Dan , Wang Min , Hu Yun-Qi , Du Chun-Guang , Yang Lan , Long Gui-Lu
Published: September 2024

Cavity optomechanical systems have received widespread attentions because they provide a novel platform for metrology, sensing, hybrid systems and quantum information processing. Their nonlinear dynamics has rich physics and plays an important role in the application scenarios. Previous works devoted to this subject have usually focused on the self-induced oscillation and chaos, whereas other parts of the rich nonlinear-dynamics picture are almost uncharted waters. In this study, we fill this gap and report the first experimental observation of limit-torus attractor, whose dynamics exhibits a torus-like trajectory in phase space. Moreover, we investigate the sharp decrease of oscillating amplitude along the up scanning transmission spectrum, referred to as catastrophe point, for the first time. The location of catastrophe point is independent of the pump power and the coupling distance. Our findings enrich the nonlinear dynamics in optomechanical systems, and open up new ways towards exploiting these systems as versatile building blocks in various applications including communication, quantum information processing, sensing and metrology.
Soliton molecules, bifurcation solitons and interaction solutions of a generalized (2 + 1)-dimensional korteweg-de vries system for the shallow-water waves
Authors: Wang Chunxia , Yin Xiaojun , Chen Liguo
Published: September 2024

The central purpose of this paper is exploring the soliton molecules, bifurcation solitons and interaction solutions of the Korteweg–de Vries system based on the Hirota bilinear method. The studied system acts as an extension of the classic KdV system for the shallow-water waves, and is very useful to contribute in nonlinear wave phenomena. Firstly, the soliton molecules are obtained by adding resonance parameters in N-soliton. Then the interaction solutions between soliton/breather and soliton molecules are studied, as well as the interaction between two soliton molecules by using N-soliton. Moreover, a class of novel bifurcation solitons are derived, including Y-type bifurcation solitons, X-type bifurcation solitons and multiple-bifurcation solitons. In the end, the dynamic properties of soliton molecules, bifurcation solitons as well as the interaction solutions are presented graphically. The developed solutions of this research are all new and can enable us apprehend the nonlinear dynamic behaviors of the generalized (2+1)-dimensional Korteweg–de Vries system better.
Impact of Al3+ substitution in M-type hexaferrite on structural, magnetic, and dielectric properties
Authors: Ahmed Mahrous R , Ibrahim E M M , Hamazaoui Adel , Rayan Abdalrahman M , Azab A A , Abdel Hakeem A M
Published: September 2024

Hexaferrites SrAlxFe12−xO19 (x = 0, 1, 2, 3, and 4) doped by Al3+ in an account of Fe3+ were synthesized using microwave digestion. X-ray diffraction pattern analysis revealed that the compound is polycrystalline with a hexagonal M-type structure of SrAlxFe12−xO19 and P63/mmc space group is predominant for all dopants of Al3+ ion. The crystallite size of the SrAlxFe12−xO19 phase has a maximum value for the un-doped sample (94.5 nm) and then decreases for all values of Al-doping. The SEM results showed that the average grain size increased with Al-doping till x = 2 and was almost stable. The magnetic properties were investigated by vibrating sample magnetometer. The results showed a continuous decrease in both saturation (Ms), and remnant (Mr), magnetization with Al-doping. At the same time, the coercive magnetic field, Hc, increases continuously with Al-doping except for x = 4, Hc slightly decreased. These results make these compound candidates to be used in data storage and magnetic memories. Dielectric properties investigation showed low-frequency dispersion in the dielectric results due to a space-charge effect. It has been demonstrated that enhancements in conductivity, dielectric constant (ε′), and dielectric loss (ε′′) rise with an increase in the concentration of Al3+ ions, suggesting that SrAlxFe12−xO19 can be used for microwave absorption and other high-frequency applications.
Roles of defects in perovskite CsPbX3 (X=I, Br, Cl): a first- principles investigation
Authors: Chen Dafei , Ding Jun , Tan Qiuhong , Yang Peizhi , Liu Yingkai , Wang Qianjin
Published: September 2024

Inorganic lead halide perovskite CsPbX3 (X=I, Br, Cl) have a promising application in optoelectronic fields due to their excellent photovoltaic properties. The defects, which have a significant impact on the performance of materials, are often introduced during the synthesis process. However, there is still a lack of systematic theoretical investigation of the effects of these defects. In this study, the effects of vacancies and H-atom interstitial point defects on the structural, electronic and optical properties of CsPbX3 are systematically investigated by using first-principles approach based on density-functional theory. The calculated results show that the introduction of different defects have significantly effect on the band gap, effective mass, semiconductor properties, ion migration and optical absorption coefficient of the perovskite materials. It is also found that VCs and VPb defects introduce shallow transition levels that do not negatively impact the optoelectronic properties. However, VX and interstitial H defects generate deep transition levels within the bandgap, which acts as non-radiative recombination centers and reduce the optoelectronic performance of the perovskite material. This study contributes to the understanding of the nature of halide chalcogenides and optimally regulating the performance of optoelectronic devices.
The yang-baxter equation, quantum computing and quantum entanglement
Authors: Chouraqui Fabienne
Published: September 2024

We present a method to construct infinite families of entangling (and primitive) 2-qudit gates, and amongst them entangling (and primitive) 2-qudit gates which satisfy the Yang-Baxter equation. We show that, given 2-qudit gates c and d, if c or d is entangling, then their Tracy-Singh product c ⊠ d is also entangling and we can provide decomposable states which become entangled after the application of c ⊠ d.
Adsorption of tryptophan by covalent organic frameworks
Authors: Li Chen , Feng Mengchu
Published: September 2024

Hemoperfusion based on adsorption has been widely used to remove the blood toxins of patients with hepatic encephalopathy. It is important to develop adsorbents with high adsorption capacity, and specific adsorption performance for toxins is highly desired for hemoperfusion. Herein, we evaluate the tryptophan adsorption performance of four kinds of covalent organic frameworks (COFs) by powder X-ray diffraction (PXRD), high-performance liquid chromatography (HPLC), and so on. Benefitting from the abundant pore, suitable pore size, and attractive effect between tryptophan and hydroxy groups in COFs, TAPB-DHTA-COF and TAPT-DHTA-COF with abundant hydroxy groups show remarkable adsorption performance for tryptophan, which is superior to commercial activated carbon. Furthermore, the selective adsorption of COF does not affect other components in the blood, thus avoiding the occurrence of other diseases. Therefore, COFs offer a promising platform for the adsorption of toxins in hemoperfusion.
Lifetime prediction of EPDM sealing materials with thermal aging under constant compression
Authors: Xie Zhaonan , Chen Junhong , Zhang Kai
Published: September 2024

EPDM (Ethylene Propylene Diene Monomer) is an important engineering sealing material. Thermal aging leads to a decline in its service life. In this study, the static sealing lifetime of EPDM sealing materials is investigated by thermal aging experiments under constant compression. Based on the variation pattern of compression set over aging time at different aging temperatures (80 °C, 100 °C, and 120 °C), a lifetime prediction model for EPDM sealing materials is derived using chemical reaction kinetics and the Arrhenius equation. The model is compared with the experimental results. The results show that the prediction model is highly reliable. The theoretical life of EPDM after thermal aging at 25 °C is 30.6 years, 53.1 years, and 89.1 years, respectively, when the compression set is 40%, 45%, and 50 %.
Effects of shapes on the deformation of thin-walled artifacts manufactured by selective laser melting
Authors: Tong Xiaona , Li Weishi
Published: September 2024

In selective laser melting technology, the metal powder is subjected to a temperature gradient effect during the melting process, leading to uneven distribution of internal stress, and thus forming residual stress after cooling. At the same time, the high temperature gradient will cause complex changes in the shape of the parts. In this paper, the selective laser melting process is simulated for several typical thin-walled test artifacts to predict the residual stress, and the fabricated artifacts are measured to evaluate the shape deformation. The results show that the sharper the local corners of a part, the greater the residual stress within it, making it more prone to significant deformation. We show that we can suppress the deformation by changing the local shape of the artifact, such as substituting sharp corners with circular fillets, or replacing straight shapes with curved ones.
Anti-icing performance and influencing factors of super-lubricated surface in simulated glaze icing
Authors: Li Bo , Bai Jie , Zhang Lusong , Xiang Huiying , Yuan Yuan
Published: September 2024

The icing of the overhead aluminum conductor has caused the conductor load to be too heavy or uneven, which results in huge accidents. The super-lubricated surface (SLIPS) shows great potential in anti-icing. Glaze ice is a common type of icing, and its damage to transmission lines is the most serious. However, the properties and influencing factors of anti-icing lubricated surfaces at glaze ice surroundings are rarely reported. In this study, the super-lubricated surface was prepared by the anodic oxidation method, and the anti-icing properties and influencing factors of surfaces were investigated in glaze ice surroundings. The results demonstrate that the SLIPS can decrease the icing amount, which is only 41% of the original aluminum surface. SLIPS exhibits excellent anti-icing performance in different environments temperatures and rainfalls. This study provides experimental guidance for the practice application of SLIPS in anti-icing aluminum conductors.
Study on preparation of ettringite-based fireproofing material for cable trench and its fireproofing mechanism
Authors: Yuan Jianguo , Ji Jun , Li Youchun , Nie Jingkai , Fan Xuming , Liu Hui , Zhang Yihang
Published: September 2024

The construction of a new power system puts forward higher requirements for the fire safety of power equipment. Fiber cement board is a kind of fire-proof material for cable trenches in electric power fields, but it cannot meet the requirement of electric fire protection. In order to meet the new requirement of high fire-proof grade for cable trench in substation, Ettringite-rich fire-proof separating material was prepared by using a metallurgical slag-sulphoaluminate cementitious system. The high temperature behavior of samples was studied by high temperature calcination test, thermal analysis and microstructure observation. The results show that the temperature rise of ettringite cementitious material is 5.2°C and 22.1°C lower than that of fiber cement board at 500°C and 1000°C respectively, and it can be used in the field of fire protection of substation cable trench. The reversible decomposition of ettringite is the main reason why ettringite-based cementitious materials can be reused.
Ionic gels with high mechanical strength enabled by supramolecular interactions between small molecular solvents and polymer chains
Authors: He Zhaoqiang , Xing Chenyang , Peng Zhengchun
Published: September 2024

The limited mechanical properties of hydrogels significantly impede their practical applications. In this research, we have synthesized supramolecular ionic gels using betaine, citric acid, and acrylamide as the main components. These specimens exhibit exceptional tensile properties (exceeding 1000% elongation at break) and toughness (approximately 3 MJ/m3), as well as recovery capabilities under substantial compressive strains. Furthermore, these transparent and conductive ionic gels have been employed in the fabrication of alternating current electroluminescent devices with single-electrode configurations. The outcomes of this study indicate that the high-strength ionic gel preparation method outlined herein shows great potential for expanding the application spectrum of ionic gels.
The research of electrochemical performance of Mg-doped NaNi1/3Mn1/3Fe1/3O2 positive electrode materials
Authors: Bai Xue , Wei Aijia , He Rui , Li Xiaohui , Zhang Lihui , Liu Zhenfa
Published: September 2024

The demand for Li-ion batteries is increasing year by year, which poses a great challenge to the scarce Li and Co resources. Na-ion batteries are considered to be one of the potential energy storage batteries because of their low raw material cost, wide source of sodium resources, and prices that are not susceptible to market fluctuations. The layered oxide positive electrode (such as NaNi1/3Mn1/3Fe1/3O2, NMF) is a potential replacement due to its high-capacity characteristics and low-cost advantages. However, the rate performance of NMF is compromised by the slow migration kinetics of Na+ ions. Here, we used the Mg doping strategy to realize the enhancement of the rates and cycling properties of NMF. Our research shows that the 2% Mg-doped cathode material has superior rate performance and cycling performance. The discharge-specific capacities are 120.5 mAh/g at 0.1C and 88.9 mAh/g for 100 cycles at 0.5C with a high retention rate (85.2%).
Analysis of thermal stability and enthalpy in SSD systems with various thickening agents
Authors: Duan Rui , Wang Jinning , Zhang Ao
Published: September 2024

Phase change materials (PCMs) play a vital role in the improvement of efficiency of cold storage air conditioning for demand side management of electrical power. To enhance the thermal stability and the enthalpy of the system, the separation of Sodium Sulfate Decahydrate (SSD) hydrate crystals from their aqueous solution is a significant factor that needs to be addressed. The melt blending technique has been used to explore the effect of various thickening agents, namely Carboxymethyl Cellulose (CMC), Xanthan Gum (XG), and Sodium Alginate (SA) on the thermal stability and enthalpy of the system. The choice of the best thickening agent and its optimum concentration led to the enhancement in the thermal stability and enthalpy of the system. Experimentally, among the three thickeners, CMC proved to be the best thickening agent that remarkably improved the thermal physical properties of the SSD formulation. The paper described the detailed experimental procedures, including melt blending set-up, thermal characterization unit, and cyclic stability test unit. The experimental results showed that the formulation, SSD-CMC at 2 wt% CMC and 50% SSD significant, improved in their thermal physical performance, wherein the enthalpy decreased from 104.23 kJ/kg to 83.71 kJ/kg over fifty cycles, which are the 19.69% of the decay for such a long cycling. It was then concluded that the results would improve the effectiveness of thermal energy storage materials and that phase change materials should be optimized to be used in sustainable and efficient cooling applications and useful for the improvement of the storage capacity of thermal energy storage solutions.
Experimental and simulation study on mechanical properties of ZK60 magnesium alloy after accumulative roll bonding
Authors: Li Shaojie , Jin Jianfeng , Wang Yongbo , Pan Hucheng , Qin Gaowu
Published: September 2024

The mechanical properties of two- and four-layered wrought ZK60 Mg alloy sheets after two passes of accumulative roll bonding (ARB) with different reduction were studied and the microstructure were analyzed. The four-layered ZK60 sheets after ARB with 50% reduction demonstrate better strength-ductility combinations with yield strength of 223 MPa, ultimate tensile strength of 327 MPa, and total elongation of 23.7%, compared with the initial ZK60 of 222 MPa, 291 MPa and 10.0%, respectively. The average grain size of four-layered ARB ZK60 sheet is reduced from 21.8 μm of the initial sample to 4.4 μm. Using a micromechanical finite element model, the strain hardening behavior of ZK60 sheet was successfully predicted. The predictions were in good agreement with the experimental results. The simulation results reveals that the high performance of ZK60 sheets may be contributed by the lamella structure formed by the fine and coarse grains, which can avoid the local stress concentration and inhibit initiation and propagation of the microcracks. These findings provide a theoretical basis for the structural optimization design of ZK60 Mg alloys.
Prediction of flow stresses for a typical Nickel-Based superalloy during hot deformation based on constitutive equation
Authors: Liu Jianxiao , Jiang Chao , Zhai Yuewen , Zhou Leyu , Zong Haiyu , Wang Huizhen , Zhan Yuheng
Published: September 2024

Utilizing the Gleeble-3500 thermal simulation testing machine, a series of isothermal constant strain rate thermal compression tests were executed to study the high-temperature rheological properties of the GH4169 alloy. These tests were carried out under deformation temperatures between 900°C and 1100°C, with strain rates from 0.001 to 1 s−1, and involved a deformation of 60%. The results reveal that the peak stress of the GH4169 alloy decreases as the temperature increases, and the strain rate decreases during hot deformation. The activation energy for thermal deformation is calculated to be 806.39 kJ/mol. Through regression analysis and polynomial fitting of true stress-strain curves from thermal compression tests, an Arrhenius constitutive equation integrating strain compensation for high-temperature deformation was established. The model exhibits an average relative error of 8.86% between predicted and experimental values, indicating the model’s good accuracy in predicting the alloy’s rheological behavior during thermal deformation. By adjusting the strain rate and deformation temperature, this model can be utilized to control the stress level in the hot working process.
The impact of induction heating time on the temperature distribution of high-temperature alloy discs
Authors: Tuermengke  , Zhu Weidong , Zhai Yuewen
Published: September 2024

The induction heating time is directly related to the temperature uniformity of high-temperature alloy disc components. Therefore, investigating the influence of induction heating time on the temperature field distribution of disc components provides guidance for temperature control strategies in the forming process. In this study, the finite element analysis software COMSOL Multiphysics was employed to examine the impact of induction heating time on the radial and thickness-wise temperature fields of GH4169 discs. The results indicate that the heating time affects the thickness of the heating layer, and appropriately extending the heating time can improve the temperature uniformity in the thickness direction, achieving a temperature difference of ±5 °C in the disc component thickness direction under certain conditions. When the heating time ranges from 1229 s to 1239 s, the temperature in the R=30 mm to R=100 mm range reaches the suitable forging temperature.
The influence of heat treatment on AlSi-polymer abradable coating
Authors: Liu Caiyan , Mao Zhengping , Xu Xiaojie
Published: September 2024

Abradable coatings, as one of the most important technologies for aero and industry gas turbine engines, have an extremely significant influence on engine performance. The macro-hardness of AlSi-Polyester for low-pressure compressor and as-sprayed coating degradation mechanism has been investigated by heat treatment process in imitation service condition. SEM (Scanning Electron Microscope) and OM (Optical Microscope) were used to observe the morphology of powder and coating microstructure in cross-section, respectively. Rockwell hardness tester was used to measure the macrohardness of coatings before and after heat treatment. It shows that AlSi-Polyester powder has an approximately spherical shape and uniform microstructure with alloy phase and polyester phase distribution in the coating prepared by air plasma spraying. Oxidation of the alloy phase and reduced polyester, as well as macrohardness in the as-sprayed coating, occur after the heat treatment process.
Fast determination of thermal conductivity of aluminum alloy by laser-induced breakdown spectroscopy
Authors: Shan Yuheng , Liu Ruibin
Published: September 2024

The matrix thermal properties are closely linked to laser-induced plasma, because it is the heat effect predominantly governs the process when the nanosecond-pulsed laser acting on the material, particularly in metallic materials. In the study using a series of pure metal samples, We detected a substantial inverse linear relationship linking the matrix’s thermal storage coefficient of the material to the temperature of the plasma. This discovery reveals that metals exhibiting reduced thermal conductivity or lower specific heat capacity necessitate a smaller amount of laser energy to achieve thermal spreading and to facilitate the transitions to the melted and vaporized states, which consequently results in a higher rate of material removal and higher plasma temperatures. Based on this correlation, a prediction model for the thermal conductivity of aluminum alloys has been developed, employing LIBS technique as analysis method, alongside PLS regression, with a relative error of below 1.5%. It presents a pioneering technique for the swift evaluation of thermal conductivity in aluminum alloys.
Determination of stress triaxiality by experiment-simulation and obtaining of johnson-cook damage criterion for Al-Mn alloy
Authors: Wang Wei , Hu Yongbo , Zhang Dashuai , Chi Dao , Wang Guobin
Published: September 2024

Al-Mn alloy is extensively implemented in new energy vehicles. Damage prediction is the key to its safety application. The Johnson-Cook (JC) constitutive relationship parameters of Al-Mn alloy were first determined by standard tensile tests to predict the damage behavior of Al-Mn alloy. Subsequently, different notch specimens were designed to study the influence of stress state on damage behavior. By combining tensile tests and simulations, the stress triaxiality of Al-Mn alloy under different stress states was accurately obtained. On this basis, the JC damage criterion parameters were obtained. Finally, the obtained JC constitutive relationship and damage criterion parameters were imported into the tensile simulation models. The results showed that the force-displacement curves of the tensile experiments and simulations matched well, which can effectively simulate the deformation and fracture behavior of the Al-Mn alloy.
Influence of heat treatment process on the microstructure and hardness of Q345B steel
Authors: Wang Yan
Published: September 2024

This paper studied and determined the heat treatment processing technology of Q345B steel, and analyzed its metallographic structure and hardness after different quenching and tempering methods. The results showed that the salt quenching cooling rate was the fastest, resulting in the most martensite and the highest hardness. The hardness of salt-quenched, water-quenched, and oil-quenched steel decreased sequentially, but all of them are significantly higher than the initial hardness of Q345B steel. 950°C was more suitable for quenching Q345B steel than 900°C, with better microstructure and hardness. After quenching, tempering is conducted, and under the same quenching process, three different types of tempering are conducted. The hardness of low-temperature tempering, medium-temperature tempering, and high-temperature tempering decreased sequentially, but they were not lower than the initial hardness of Q345B steel.
Synthesis and thermophysical properties of rare-earth tantalate ZrO2-Dy3TaO7 ceramics
Authors: Li Dongbo , Zhang Ming , Deng Ge , Yang Yuan , Gui Rong , Yang Guizhong
Published: September 2024

Thermal Barrier Coatings (TBCs) are of major concern to researchers because of their outstanding properties, such as high-temperature resistance, compressive resistance, hardness, and toughness. Its applications are wide-ranging and critical. Examples include hypersonic vehicles, aero-engines, and service in high-temperature and high-impact extreme environments. This work focuses on the preparation, thermal properties (coefficient of thermal expansion, thermal conductivity), and performance evaluation (thermal shock resistance, thermal shock resistance, and bonding) of ZrO2-Dy3TaO7 rare earth tantalate ceramic coating materials. The results show that ZrO2-Dy3TaO7 possesses a low thermal conductivity (1.25-1.50 W K−1 m−1, 900°C), a high thermal expansion coefficient (10.80-11.14×10-6 K−1, 1200°C), which is about half of the value of the thermal conductivity of 7YSZ (2.8-2.2 W K−1m−1). It is better than that of the 7YSZ (10.04×10−6 K−1, 1200°C), which meets the performance requirements of the new thermal barrier coating. In addition, ZrO2-Dy3TaO7 can achieve more than 6, 000 thermal fatigue cycles at 1200°C, and the ideal number of thermal shock cycles is 4, 040 cycles at the same temperature. These outstanding test results demonstrate that the ceramic coating can effectively protect the substrate material and provide long-term service in high-temperature copper liquid. This research lays the theoretical foundation for the development of next-generation coating materials, particularly for thermal barrier/environmental barrier integrated coating materials.
The enhanced aging hardening behavior in Si-containing Al-5Zn-1Mg-1Cu alloys
Authors: Lu Yi , Wen Shengping , Nie Zuoren
Published: September 2024

The ageing behaviour and phase transformation of a range of Si-microalloyed low Mg/Zn ratio Al-5.0Zn-1.0Mg-Cu alloys were investigated at a temperature of 150°C by using TEM and microhardness tests. Adding Si had a important influence on the proportion of precipitates and microhardness. As Si content increased, the precipitated phase underwent a gradual transition from the T+η precipitates to the fine GPB-II precipitates. Concurrently, the microhardness exhibited a notable enhancement from 120 HV to 150 HV when the alloys were subjected to 150°C aging. Existence of small and even GPB-II phases in the Si-adding alloy was identified as underlying cause of this result. This GPB-II phase exhibited a bilayer microstructure. In core region predominantly comprise Zn, Si and Mg, and the shell region primarily consist of Zn and Cu. This structure effectively inhibited phase growth, maintaining the phases at a smaller scale and enhancing the alloy’s hardening effect.
Research on the influence of finish rolling technique parameters on H2S corrosion resistance behavior of pipeline steel in the thickness direction
Authors: Fan Yanqiu , Ma Changwen , Li Shaopo , Ding Wenhua , Wang Longhe , Liu Yang , Li Zhanjun
Published: September 2024

Natural gas was an important energy for human society’s development, and there was still a great demand for this type of energy. It required pipeline steel for energy transport and had excellent hydrogen-induced cracking resistance. Thermomechanical controlled processing (TMCP) was a frequently used manufacturing method for pipeline steel. It was necessary to research the effect of finish rolling technique parameters on the H2S corrosion resistance behavior of pipeline steel in the thickness direction, especially concerning microstructure and hardness in the thickness direction. So, for the research, optical microscope (OM), hydrogen-induced cracking tests (HIC), and hardness tests were used to study the effect of finish rolling technique parameters on H2S corrosion resistance. As finish rolling deformation increases, deformation can effectively conduct from surface to center and reduce the average hardness gap between the surface and the center. It can also generate finer microstructure and smaller hardness differentials from the thickness direction. All these can enhance the hydrogen-induced cracking resistance.
Shape and roundness accuracy prediction of the roll grinding based on improved Elman neural network
Authors: Gao Hui-Min , Ren Xin-Yi , Xu Hai-Wei , Ai Jiao-Jian , Guo Min
Published: September 2024

Due to the strong nonlinear relationship between the shape and roundness of the roller and the grinding process parameters, a prediction method for roll shape error and roundness error based on an improved Elman neural network is proposed. During the training process of the Elman neural network, Sine chaotic mapping is used to make the population distribution more uniform, and the sparrow search algorithm is used to obtain the optimal parameters of the Elman neural network. The verification results show that the prediction errors of the roll shape and roundness are both less than 10%, and the accuracy of the prediction model is higher than 85%, which proves the effectiveness of the proposed method.
Research on the effect of manufacturing processes on the fatigue life of TC4 fasteners
Authors: Ma Yanyun , Dou Zhaofeng , Li Haoshan , Wang Ruiyuan , Xia Yanfeng , Gao Qiu , Zhang Weifang
Published: September 2024

TC4 fasteners have the characteristics of high specific strength and yield ratio, excellent high and low temperature performance, corrosion resistance, etc., and are widely used in many fastener fields, including aerospace. In long-term use, fatigue fracture has become the main failure mode of TC4 bolt fasteners. The common manufacturing processes of TC4 fasteners include shot peening, bottom corner rolling pressure, anodizing and molybdenum disulphide coating, etc. At present, few researchers have studied the effect of the stress level of the manufacturing process on the fatigue life of TC4 fasteners. Therefore, this paper designs the process and parameter influence test from the perspective of different manufacturing processes, and analyses the fatigue test results to reveal the influence mechanism of different processes on the fatigue life of TC4 fasteners. The research results show that the increase of residual compressive stress greatly improves the fatigue strength of fasteners, the shot peening process improves the fatigue life of TC4 fasteners by increasing the residual stress of fasteners, and rolling pressure also increases the surface residual compressive stress. However, it is necessary to find suitable rolling parameter values, and anodizing reduces the residual compressive stress of fasteners. The coating of molybdenum disulfide also reduces the residual stress value of the fastener surface and leads to a decrease in fatigue life. Therefore, in order to control the fatigue life of TC4 fasteners, it is necessary to carry out the shot peening process, and control the rolling pressure, anodizing time and the coating thickness of molybdenum disulfide. The research in this paper provides a reference for the subsequent research on fastener fatigue strength control.
Study on no IMC Solid state bonding method for high-density 2.5D/3D integration
Authors: Li Zongyang , Qu Zhibo , Yao Quanbin , Lin Pengrong , Xie Xiaochen , Guo Hengtong , Wang Jiaxing , Hou Pengyan , Gu Songzhao
Published: September 2024

Chiplet integration is a new development direction for the continuation and even goes beyond Moore’s Law, and in order to achieve the high density, high reliability, high-speed Chiplet device, a new method of 2.5D/3D integration approach is needed to fulfill the needs to Chiplet heterogeneous devices. In this work, two dies were successfully bonded via low energy input with no IMC solid state bonding under 220°C and 5 MPa, which is much gentler than the other solid state bonding approaches. Each die had a matrix of 22500 Cu pillars with a diameter of 20 μm. This method was promising for the near future high-density 2.5D/3D integration.
Influence of multi-process parameter linkage on the formation of lack of fusion defects based on SYSWLED simulation analysis
Authors: Yan Chen , Yang Die , Han Laihui , Zhao Zhonggang , Li Zengzhen , Sui Yongli
Published: September 2024

The lack of fusion defects remains a significant challenge in narrow-gap automatic welding of pipeline circumferential joints and then becomes the primary factor affecting pipeline longevity. The influence of multi-process parameter linkage on the welding temperature field and formation of lack of fusion defects was investigated based on orthogonal experiments and SYSWELD finite element simulation. The results indicated that welding current and speed had the most significant influence on the welding temperature field. At the same time, oscillation width affected the ability to obtain arc temperature on both sides of the weld groove. Oscillation time and edge dwell time determined the duration of arc heating on one side of the groove. A serrated temperature field morphology may occur when the dwell time is too long, leading to a lack of fusion defects. There were interactive effects among various welding parameters. Increasing heat input could reduce the risk of a lack of fusion defects. Besides, a reasonable setting of oscillation width, oscillation time, and edge dwell time could also reduce the formation risk of lack of fusion defects.
Structural, magnetic, and electrical properties of LaMnO3 doped with Na by microwave-assisted synthesis method
Authors: Chen Guohao , Jiang Luwen , Li Chunlai , Wei Yiqun , Hu Guoqing , Yue Yutao , Wang Xiaomeng , He Jin
Published: September 2024

The electric and magnetic transport properties of La1-xNaxMnO3 (x = 0.15, 0.2, 0.25, 0.3) are studied using the X-ray diffraction (XRD), vibrating sample magnetometer (VSM), and four-probe resistivity measurement method. The samples are synthesized by the method of microwave heating. The obtained samples show phase changes around x = 0.25. The magnetization measurement shows the curie temperature (Tc) increases as the level of doping increases and saturates around x = 0.25. The resistivity measurement dramatically decreases at a metal-insulator transition temperature close to Tc. These findings are discussed along with the structural features of different Na concentrations.