通讯机构：
[Zhu, HM ; Zhou, J] U;Univ South China, Sch Mech Engn, Key Lab Hunan Prov Equipment Safety Serv Technol E, Hengyang 421001, Hunan, Peoples R China.
关键词：
激光技术, 激光定向能量沉积, Ti6Al4V合金, 大气环境, 力学性能, laser technique, laser direct energy deposition, Ti6Al4V alloy, atmospheric atmosphere, mechanical properties
摘要：
在大气环境下采用激光制备Ti6Al4V（TC4）合金时受大气中氮气和氧气的影响，易形成氮化物和氧化物等脆硬相，导致裂纹等缺陷产生。本团队设计了一种适于大气环境下激光增材制造TC4合金的带空气防护罩的新型喷嘴，对比研究了有/无空气防护罩下制备的TC4合金的微观组织与力学性能。基于组分传输和k?ε气体模型，采用计算流体动力学（CFD）模拟了多流道喷嘴的功能原型。结果表明：在空气防护罩的保护下，试样表面附近的氮气、氧气含量显著降低，试样的微观组织由α′马氏体、魏氏α组织、β相和纳米相Ti3AlC2组成，试样的极限抗拉强度、屈服强度、断后延伸率和显微硬度分别为1037 MPa、952 MPa、10.2%、365 HV，与目前文献报道的普遍采用密闭环境制备的TC4合金的性能相当。 您的浏览器不支持 audio 元素。AI语音播报 Objective The laser fabrication of Ti6Al4V (TC4) alloy in an atmospheric environment is susceptible to nitrogen (N) and oxygen (O); consequently, defects such as cracks can occur because of the induced embrittled nitride and oxide phases. Therefore, the industrial application of LDED (laser direct energy deposition) -treated titanium alloy components has been severely hindered by the limited space and high cost in the closed environment. In this study, a novel nozzle with a protective hood was designed for the laser additive manufacturing of TC4 alloys to alleviate the adverse effects of N and O in an atmospheric environment. The microstructures and mechanical properties of the as-deposited TC4 specimens with and without hoods (named TC4-Y and TC4-N, respectively) were evaluated. A functional prototype of the multiflow-path nozzle was developed using computational fluid dynamics (CFD) simulations with species transport and the k?ε gas model. This study significantly benefits the laser fabrication of low-cost and high-performance Ti components in various industrial fields. Methods Gas-atomized TC4 powder with an average size range of 75 μm was employed to fabricate LDED-treated specimens using an FL-1500 1.5 kW fiber laser. The processing parameters were set as follows: laser power, 500 W; scanning speed, 600 mm/min; and powder delivery rate, 4.85 g/min. Both the central and side gases are high-purity Ar (99.99%) and were flowed at a rate of 10 L/min. CFD simulations of the gas flow adjacent to the substrate surface, which was located 2.5 mm away from the nozzle of the air hood, were performed to evaluate the effectiveness of the hood. To investigate the microstructural evolution of the LDED-treated TC4 alloy, the samples were polished and then etched with Kroll's reagent. The phase compositions were determined using a Miniflex600 X-ray diffractometer (XRD). The microstructure was investigated using a MERLIN scanning electron microscope (SEM) operated at an accelerating voltage of 20 kV and a JEOL-2100 transmission electron microscope (TEM) operated at 200 kV. The mechanical properties of the samples were evaluated using an HVS-1000 microhardness tester and a PWS-E100 universal testing machine. Results and Discussions The simulation results indicate that the facet average mass fractions of N2 and O2 reduced significantly from 1.628×10-3 to 2×10-4 and from 4.37×10-4 to 5.4×10-5, respectively (Fig. 3), which agree well with the experimental results. The TC4-N specimen is composed of needle-like α′ martensite, Widmanst?tten α-laths, β-phase, and nitrides (Figs. 6?8). By applying the protective hood, the TC4-Y specimen exhibits a decrease in α/α′ martensite content, an increase in the β-phase fraction, and the precipitation of Ti3AlC2 phase (Figs. 6?8). The average microhardness values of the TC4-N and TC4-Y specimens are 410 HVand 365 HV(Fig. 4), respectively. The higher microhardness of the TC4-N specimen is primarily due to the in-situ formation of hard nitride TiN (2900 HV) during LDED. In comparison, the TC4-Y samples indicate a slightly lower value (365 HV) that is equivalent to those fabricated in a chamber filled with an inert gas (316?369 HV). Under the protection of the hood, the TC4-Y samples exhibit an average UTS of 1037 MPa, a YS of 952 MPa, and an EL of 10.2% (Fig. 5), which are comparable to those of TC4 counterparts achieved in a closed environment. This demonstrates the effectiveness and feasibility of the protective hood. Conclusions The newly designed protective hood effectively eliminates the adverse effects of N and O. A CFD simulation was conducted, which demonstrated that the hood successfully prevented contamination by impurities, including N and O. The N and O mass fraction adjacent to the sample surface decreased by 1.38×10-3 and 5.7×10-4, respectively. The TC4-N specimen is composed of needle-like α′ martensite, Widmanstatten α-laths, β-phase, and nitrides. The TC4-Y specimen primarily comprises coarsened α′ martensite, Widmanstatten α-laths, Ti3AlC2 nanoprecipitates, and β-phase. Under the synergistic effect of refinement strengthening, solid-solution strengthening, and second-phase strengthening, the TC4-N specimen exhibits higher levels of strength (UTS of 1249 MPa, YS of 1028 MPa) and microhardness (410 HV). By contrast, an exceptional combination of high strength (UTS of 1037 MPa, YS of 952 MPa) and high ductility (10.2%) is achieved owing to the presence of α/α′ with a low aspect ratio, a high fraction of β-phase, and Ti3AlC2 nanoprecipitates in the TC4-Y specimen. This study reports a simple yet effective approach for producing LDEDed TC4 alloys with outstanding mechanical properties in an atmosphere, which significantly benefits industrial applications.
期刊：
Journal of Materials Science,2025年60(8):3957-3973 ISSN：0022-2461
通讯作者：
Qiu, CJ
作者机构：
[Yang, Tong; Qiu, Changjun] Univ South China, Sch Resource Environm & Safety Engn, Hengyang 421001, Peoples R China.;[Yang, Tong; Chen, Pinghu; Zhao, Li; Wu, Wenxing; Qiu, Changjun] Key Lab Hunan Prov Equipment Safety Serv Technol E, Hengyang 421001, Peoples R China.;[Chen, Pinghu; Zhao, Li; Qiu, Changjun] Univ South China, Sch Mech Engn, Hengyang 421001, Peoples R China.
通讯机构：
[Qiu, CJ ] U;Univ South China, Sch Resource Environm & Safety Engn, Hengyang 421001, Peoples R China.;Key Lab Hunan Prov Equipment Safety Serv Technol E, Hengyang 421001, Peoples R China.;Univ South China, Sch Mech Engn, Hengyang 421001, Peoples R China.
摘要：
Laser additive manufactured high gamma '-phase nickel-based superalloys have a high cracking susceptibility due to the unique characteristics of superalloys, which can hinder their widespread application. This work overcomes the above challenges via a compositional optimization strategy, and a novel nickel-based superalloy with high gamma ' phase has been developed via laser directed energy deposition (LDED). The effects of the various Al + Ti (1:1) contents (6.4, 6.6 and 6.8 wt.%) on microstructure and mechanical properties (room temperature, 850 degrees C and 900 degrees C) of the as-deposited and heat-treated specimens were investigated. Ultimately, the crack-free Ni-based superalloy has been successfully designed and fabricated by LDED, featuring a high gamma ' phase content. The results indicated that the gamma ' phase content and the number of the MC carbide particles increase with the increasing Ti + Al content. When the Ti + Al content is 6.6 wt.%, the newly designed Ni-based superalloy exhibits exceptional tensile properties (UTS: 1450 +/- 42 MPa, YS: 1100 +/- 36 MPa and EL: 16.5 +/- 1.1%). After heat treatment, the gamma ' phase, bulk-like (MC), long strips-like (M23C6) carbide and moderate amount of needle-like sigma phase are present in the alloy with Ti + Al content of 6.6 wt.%. Therefore, the newly designed Ni-based superalloy exhibits superior tensile properties at 850 degrees C (UTS: 818 +/- 34 MPa, YS: 774 +/- 29 MPa and EL: 10 +/- 0.7%) and 900 degrees C (UTS: 581 +/- 28 MPa, YS: 558 +/- 20 MPa and EL: 11.7 +/- 0.9%). This approach provide a new alloy design route for achieving optimization of high-temperature mechanical properties and formability of nickel-based superalloys with high gamma ' phase for laser additive manufacturing.
摘要：
Specifically exposed planes could play a crucial role in the chemical activity of nanomaterials. The morphology and structure of nano-structured WO3 particles with {020} exposure planes were successfully controlled via hydrothermal synthesis technology by adjusting the synthesis temperature and time. Additionally, the gas-sensing properties of sensors fabricated using these WO3 particles were investigated to detect different volatile gases. All the samples were found to be sensitive to alcohol gas, and the WO3 nanoparticles synthesized at 150 °C for 12 h exhibited excellent gas-sensing properties, which shows that these WO3 nanoparticles can act as an efficient gas-sensing material for the one-site selective detection of ethanol.
Specifically exposed planes could play a crucial role in the chemical activity of nanomaterials. The morphology and structure of nano-structured WO3 particles with {020} exposure planes were successfully controlled via hydrothermal synthesis technology by adjusting the synthesis temperature and time. Additionally, the gas-sensing properties of sensors fabricated using these WO3 particles were investigated to detect different volatile gases. All the samples were found to be sensitive to alcohol gas, and the WO3 nanoparticles synthesized at 150 °C for 12 h exhibited excellent gas-sensing properties, which shows that these WO3 nanoparticles can act as an efficient gas-sensing material for the one-site selective detection of ethanol.
摘要：
The significance of biomedical applications of friction stir processing (FSP) is best emphasized by their prospect utilization in improving the biomedical properties of metallic implants for orthopedic applications. FSP facilitates the stable incorporation of functional elements into implant materials for tailored modification of performance, preserves the advantageous properties of the matrix while mitigates inherent weaknesses, and provides a customized solution to multifaceted challenges that affects the long-term functionality of implants. This remarkable advantage in reinforcing properties gives FSP the ability to improve biomedical properties in metallic implants for orthopedic applications. This review (i) provides an overview of the current status and issues of metallic implants for orthopedic applications, with a special attention to the potential of FSP to address the performance decay commonly encountered by implant materials. (ii) details the principles for the development of FSP process parameters to the performation modification of implant materials, (iii) introduces the customized design of implant materials by FSP (including magnesium alloys, titanium alloys and other alloys, as well as their physico-mechanical properties and implant application), and (iv) highlights the influence of FSP on the biological functionality of implant materials. Also explored are the main challenges and perspectives in developing FSMed metallic implants for orthopedic applications.
The significance of biomedical applications of friction stir processing (FSP) is best emphasized by their prospect utilization in improving the biomedical properties of metallic implants for orthopedic applications. FSP facilitates the stable incorporation of functional elements into implant materials for tailored modification of performance, preserves the advantageous properties of the matrix while mitigates inherent weaknesses, and provides a customized solution to multifaceted challenges that affects the long-term functionality of implants. This remarkable advantage in reinforcing properties gives FSP the ability to improve biomedical properties in metallic implants for orthopedic applications. This review (i) provides an overview of the current status and issues of metallic implants for orthopedic applications, with a special attention to the potential of FSP to address the performance decay commonly encountered by implant materials. (ii) details the principles for the development of FSP process parameters to the performation modification of implant materials, (iii) introduces the customized design of implant materials by FSP (including magnesium alloys, titanium alloys and other alloys, as well as their physico-mechanical properties and implant application), and (iv) highlights the influence of FSP on the biological functionality of implant materials. Also explored are the main challenges and perspectives in developing FSMed metallic implants for orthopedic applications.
摘要：
Surface structuring has attracted growing interest in the industry due to its potential to improve the macroscopic properties of workpieces. This work investigated the surface structuring of metals by combining thermal oxide film mask and laser lithography with isotropic etching. The metals were thermally oxidized to form a protective oxide film, laser ablation patterned the thermal oxide film, while electrochemical etching operated in the isotropic mode obtained an array of hemispherical cavities. The isotropic etching potential for different metals is taken from the mass transport region of the polarization curve. The effects of thermal oxide film thickness and laser ablation area on the uniformity of the etching holes were studied. The thermal oxidation of TA2 at 350 degrees C formed a 20-nm-thick oxide film, while an array of 10 mu m radius hemispherical microcavities was fabricated on the laser patterning surface via electrochemical etching at 2 V for 1 min. The surface structuring of stainless steel, pure nickel, and tungsten is highly dependent on the ability of the oxide film to avoid electrochemical reactions. The feasibility of combining thermal oxidation and laser lithography with electrochemical etching is of great value for the surface structuring of metallic materials for biomedical and microsystem applications.
期刊：
Particulate Science and Technology,2025年43(4):637-650 ISSN：0272-6351
通讯作者：
Deng, R
作者机构：
[Deng, Rong; Luo, Yufeng; Deng, R] Univ South China, Sch Mech Engn, Hengyang 421000, Hunan, Peoples R China.;[Li, Sizhong] Hunan Hergelix intelligent Technol Co LTD, Shachang, Hunan, Peoples R China.
通讯机构：
[Deng, R ] U;Univ South China, Sch Mech Engn, Hengyang 421000, Hunan, Peoples R China.
关键词：
Fresh concrete;DEM;B m;shape and content of coarse aggregate;specific surface area
摘要：
In this paper, the effect of the coarse aggregate (CA) shape and content on the flow performance index of fresh concrete in the L-box test (B m ) was investigated based on Discrete Element Method (DEM). The Hertz-Mindlin-JKR (Johnson-Kendall-Roberts) contact model was used to characterize the constitutive relationships of fresh concrete. The parameters of contact model were calibrated by the experiment and simulation of the slump test, L-box flow test and V-funnel test. The shape of CA was quantitatively characterized, and a functional relationship between the specific surface area of concrete (S C ) and surface energy was established. The effect of CA shape and content on B m was studied numerically. The simulated results of single-shape CA concrete in L-box test show that the shape of CA affects the resultant force and flow velocity of the tracked concrete in the x direction, thus affecting the B m . The smaller the sphericity index of CA, the larger the specific surface area and the smaller the B m . The results of orthogonal tests show that the CA content of different shape in concrete affects B m with different degree. The larger the specific surface area of coarse aggregate (S CA ), the greater the negative effect on B m . A linear relationship between S C and B m was established. An equation for predicting B m based on shapes and contents of CA was presented. It shows that the more complex the shape of CA and the higher its content, the smaller the B m .
通讯机构：
[Qu, W ] U;Univ South China, Sch Mech Engn, Hengyang, Peoples R China.
关键词：
Axial force;temperature variation;Galerkin-eigenvalue method;eigenvalue method;natural frequency
摘要：
This paper examines the effects of axial force and temperature changes on the dynamic characteristics of pipes. The Galerkin method, combined with the eigenvalue method, is employed to solve the fluid-structure interaction (FSI) motion equations for the pipe. The study investigates the impact of axial force, temperature changes, fluid velocity, fluid pressure, and pipe structure parameters on the pipe's natural frequency. Numerical results reveal that different parameters have varying effects on the pipe's natural frequency, leading to the determination of stability conditions' varying influences. Combined with the finite element method (FEM), the impact of temperature changes on the pipe's natural frequency is analyzed. The correctness of the numerical results of the Galerkin-eigenvalue method was verified through comparative methods. The research results confirm that this numerical method provides strong theoretical support for analyzing the nonlinear dynamic characteristics of pipelines under temperature changes in random vibration environments. This is of guiding significance to the vibration reduction design of the pipeline system and helps prevent and reduce the structural damage and accident risks caused by the change in the pipeline's dynamic characteristics.
作者机构：
[Shangting Jiang; Ye Li] School of Nuclear Science and Technology, University of South China, Hengyang, Hunan 421001, China;[Ye Zhang; Changchang Chen] Hunan Province Key Laboratory for Ultra-Fast Micro/Nano Technology and Advanced Laser Manufacture, College of Mechanical Engineering, University of South China, Hengyang, Hunan 421001, China;[Zhiyong Chen; Weihua Zhu] School of Electrical Engineering, University of South China, Hengyang, Hunan 421001, China;School of Electronics Information and Electrical Engineering, Yangtze University, Jingzhou 434023, China;[Hongyu He] Hunan Province Key Laboratory for Ultra-Fast Micro/Nano Technology and Advanced Laser Manufacture, College of Mechanical Engineering, University of South China, Hengyang, Hunan 421001, China<&wdkj&>School of Electronics Information and Electrical Engineering, Yangtze University, Jingzhou 434023, China
通讯机构：
[Hongyu He] H;Hunan Province Key Laboratory for Ultra-Fast Micro/Nano Technology and Advanced Laser Manufacture, College of Mechanical Engineering, University of South China, Hengyang, Hunan 421001, China<&wdkj&>School of Electronics Information and Electrical Engineering, Yangtze University, Jingzhou 434023, China
摘要：
Four layer hexagonal SiC (4H-SiC) is a promising material for high temperature and high radiation environments, attributed to its excellent thermal conductivity and radiation resistance. However, the mechanism of radiation displacement cascades in 4H-SiC remains incomplete. This study employs molecular dynamics (MD) to explore the effects of radiation energy, direction and environmental temperature on displacement cascades in 4H-SiC. We simulated radiation displacement cascades in 4H-SiC under radiation energy ranging from 2 KeV to 10 KeV and temperature ranging from 0 K to 2100 K. We analyzed the variation pattern of radiation defects and clusters. We derived the empirical formulas describing the variation of defects and clusters with radiation energy and radiation direction. We revealed patterns in the number of radiation defects and clusters under different temperature. The findings enhance our understanding of radiation displacement cascades in 4H-SiC, providing valuable empirical formulas for predicting the behaviors of defects and clusters under varying radiation energy and temperature conditions, and have practical implications for designing materials resilient to radiation in semiconductor devices.
Four layer hexagonal SiC (4H-SiC) is a promising material for high temperature and high radiation environments, attributed to its excellent thermal conductivity and radiation resistance. However, the mechanism of radiation displacement cascades in 4H-SiC remains incomplete. This study employs molecular dynamics (MD) to explore the effects of radiation energy, direction and environmental temperature on displacement cascades in 4H-SiC. We simulated radiation displacement cascades in 4H-SiC under radiation energy ranging from 2 KeV to 10 KeV and temperature ranging from 0 K to 2100 K. We analyzed the variation pattern of radiation defects and clusters. We derived the empirical formulas describing the variation of defects and clusters with radiation energy and radiation direction. We revealed patterns in the number of radiation defects and clusters under different temperature. The findings enhance our understanding of radiation displacement cascades in 4H-SiC, providing valuable empirical formulas for predicting the behaviors of defects and clusters under varying radiation energy and temperature conditions, and have practical implications for designing materials resilient to radiation in semiconductor devices.
摘要：
The accurate prediction of failure boundaries in engineering applications is essential for ensuring safety and reliability. Traditional methods often rely heavily on high-fidelity physical experiments or numerical simulations, which are prohibitively expensive and time-consuming. In response to this challenge, our research proposes an innovative multi-fidelity support vector classification approach that leverages an abundant supply of low-fidelity data alongside a limited amount of high-fidelity data. This combination significantly reduces modeling costs while maintaining or even enhancing predictive accuracy. The key points of the proposed method include the design of a reasonable kernel function to effectively describe the relationship between the input and output of multiple fidelities, and the determination of the optimal hyperparameters. In addition, in practical engineering problems, real data often exhibit data imbalance, leading to poor performance of the trained models. Our novel method addresses this limitation by integrating a strategy for managing the data imbalance. By effectively treating data imbalance, our approach significantly improves the classification and boundary prediction capabilities of the model. To validate our method, we applied it to three distinct engineering problems: predicting the failure boundary of a zero Poisson ratio structure, analyzing surge and choke boundaries in an axial flow compressor rotor, and tackling a 31-dimensional simulation failure boundary prediction problem within the computational fluid dynamics context of the same rotor. The results demonstrate that our multi-fidelity support vector classification method not only effectively predicts boundaries in these practical scenarios but also outperforms alternative methods, showing its potential as a powerful tool for engineers.
摘要：
With the rapid development of flexible wearable electronic products, their application fields and demands are increasing, posing new challenges to flexible conductive materials. This paper selected flexible polydimethylsiloxane (PDMS) as the substrate. In order to enhance the adhesion between the substrate and the metal coating, dopamine and silanization were used to co-modify its surface. A conductive layer of metallic copper is deposited on its surface using an inexpensive, easy-to-use electroless plating technique. By optimizing the process conditions, it is found that a uniform copper layer of about 0.6 μm can be formed on the surface of the substrate by electroless plating at a constant temperature of 45°C for 30 min with a conductivity of 5556 S/cm. The relative resistance changes under different deformation conditions, and the I-V curve of the LED circuit is not very different. Therefore, this paper prepared a flexible conductor with excellent electrical conductivity, high coating adhesion, and good electrical stability under large-scale deformation.
With the rapid development of flexible wearable electronic products, their application fields and demands are increasing, posing new challenges to flexible conductive materials. This paper selected flexible polydimethylsiloxane (PDMS) as the substrate. In order to enhance the adhesion between the substrate and the metal coating, dopamine and silanization were used to co-modify its surface. A conductive layer of metallic copper is deposited on its surface using an inexpensive, easy-to-use electroless plating technique. By optimizing the process conditions, it is found that a uniform copper layer of about 0.6 μm can be formed on the surface of the substrate by electroless plating at a constant temperature of 45°C for 30 min with a conductivity of 5556 S/cm. The relative resistance changes under different deformation conditions, and the I-V curve of the LED circuit is not very different. Therefore, this paper prepared a flexible conductor with excellent electrical conductivity, high coating adhesion, and good electrical stability under large-scale deformation.
期刊：
Virtual and Physical Prototyping,2025年20(1) ISSN：1745-2759
通讯作者：
Li Li<&wdkj&>Jinghao Huang
作者机构：
Hunan Provincial Key Laboratory of Emergency Safety Technology and Equipment for Nuclear Facilities, University of South China, Hengyang, People’s Republic of China;School of Mechanical Engineering, University of South China, Hengyang, People’s Republic of China;[Li Li] State Key Laboratory of Intelligent Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, People’s Republic of China;[Weiwei Xiao; Yilong Liu; Jinghao Huang; Shuliang Zou; Zhenghao Ren; Shihong Liu; Yanli Wang] Hunan Provincial Key Laboratory of Emergency Safety Technology and Equipment for Nuclear Facilities, University of South China, Hengyang, People’s Republic of China<&wdkj&>School of Mechanical Engineering, University of South China, Hengyang, People’s Republic of China
通讯机构：
[Li Li] S;[Jinghao Huang] H;State Key Laboratory of Intelligent Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, People’s Republic of China<&wdkj&>Hunan Provincial Key Laboratory of Emergency Safety Technology and Equipment for Nuclear Facilities, University of South China, Hengyang, People’s Republic of China<&wdkj&>School of Mechanical Engineering, University of South China, Hengyang, People’s Republic of China
关键词：
Laser-directed energy deposition;B 4 C/Al composites;excellent ductility;microstructure;mechanical property;electrochemical corrosion
摘要：
Aluminum matrix boron carbide (B 4 C/Al) composites with moderate strength but excellent ductility are fabricated by laser-directed energy deposition (LDED) with different laser powers. The microstructural features underlying the outstanding mechanical properties of such fabricated composites have been fully explored. The mechanism of the excellent ductility without notably sacrificing strength is attributed to dislocation formation, grain refinement, and precipitation effect, which could therefore advance the state-of-art in the field of B 4 C/Al composites. The influence of laser power on the microstructure, mechanical, and corrosion properties is also investigated. The composite fabricated by the laser power of 1200 W has the best corrosion resistance. It is found that pitting is the primary type of corrosion of the LDED B 4 C/Al composites in H 3 BO 3 solution, and it is most likely to occur at the interface between Al and B 4 C particles. These findings highlight that the LDED process can fabricate high-performance corrosion-resistant composites.
摘要：
Ti6Al4V-10 wt%Gd 2 O 3 (TC4–10Gd 2 O 3 ) composites were fabricated by vacuum sintering. And the influence of sintering temperature on the microstructure, mechanical and corrosion properties of the fabricated composites was investigated. The results indicate that Ti in the fabricated composites appears in aggregated or thin strip form, with α phase and β phase coexist. As the sintering temperature increases, the density, hardness, compressive strength, and strain of the composites also increase. It was found that pitting was the main corrosion form of the fabricated TC4–10Gd 2 O 3 composite, And pitting corrosion mostly occurs at the interface between agglomerated Ti and Gd 2 O 3 . In low concentration H 3 BO 3 solution, the main corrosion product of Ti in the composites was Ti 2 O 3 , while in high concentration H 3 BO 3 solution, the main corrosion product was Ti 3 O 5 .
Ti6Al4V-10 wt%Gd 2 O 3 (TC4–10Gd 2 O 3 ) composites were fabricated by vacuum sintering. And the influence of sintering temperature on the microstructure, mechanical and corrosion properties of the fabricated composites was investigated. The results indicate that Ti in the fabricated composites appears in aggregated or thin strip form, with α phase and β phase coexist. As the sintering temperature increases, the density, hardness, compressive strength, and strain of the composites also increase. It was found that pitting was the main corrosion form of the fabricated TC4–10Gd 2 O 3 composite, And pitting corrosion mostly occurs at the interface between agglomerated Ti and Gd 2 O 3 . In low concentration H 3 BO 3 solution, the main corrosion product of Ti in the composites was Ti 2 O 3 , while in high concentration H 3 BO 3 solution, the main corrosion product was Ti 3 O 5 .
通讯机构：
[Li, ZY ] U;Univ South China, Coll Mech Engn, Hengyang 421001, Peoples R China.
关键词：
conductivity;conformation of PEDOT;organic photovoltaics;transmittance;work function
摘要：
Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is widely utilized as the hole transport layer (HTL) inorganic photovoltaics (OPVs) because of its low-temperature solution processing peculiarity, high optical transmittance, and excellent mechanical flexibility. However, the core-shell structure of PSS coated PEDOT results in relatively low conductivity, work function, transmittance and waterproofness of PEDOT:PSS interlayer, limiting the photovoltaic performance and stability of OPVs. Here, the conformation of PEDOT chains are regulated from helical benzoyl to linear quinone structure via incorporation of 2D Cd(0.85)PS(3)Li(0.15)H(0.15)dopant into the conventional PEDOT:PSS interlayer, promoting an interpenetrating network structure in PEDOT:PSS interlayer and forming an efficient hole transport channel from active layer to ITO electrode. Such features significantly improve the electrical conductivity, work function, and transmittance of PEDOT:PSS interlayer. In consequence, the maximum power conversion efficiency (PCE) of D18:L8-BO, PBDB-T:ITIC, as well as PTzBI-dF:L8-BO based OPVs ameliorated from 18.37%, 8.94%, and 15.80% to 19.26%, 10.00%, and 16.83%, respectively. The application of Cd(0.85)PS(3)Li(0.15)H(0.15) doping PEDOT:PSS strategy demonstrates great potential for the development of strongly conductive, large-work-function, highly transparent, and excellent-waterproof PEDOT:PSS interlayer toward highly efficient and stable OPVs.
摘要：
Cicada wing exhibiting a high transparency at wide viewing angles can be bioinspired for the formation of antireflective subwavelength array (ASA), which can effectively enhance surface transmittance of infrared window for infrared detection. Due to extreme fine structure of the ASA and significant limitations of single pulse Gaussian beam manufacturing accuracy, it still a challenge to fabricate ASA with broadband and mechanically-durable properties by femtosecond laser. In this study, a novel temporal-spatial shaping femtosecond laser micromachining is proposed to fabricate inverted cone pattern ASA on zinc sulfide (ZnS) substrate for suppressing surface Fresnel reflection and realizing high infrared transmittance. Femtosecond laser double-pulse Bessel beam is used to experimentally fabricate the ASA with tunable depth and width by laser power and pulse delay. The bioinspired ASA is manufactured on ZnS, achieving high transmittance of 88 % in the wavelength of 4–12 μm, good laser damage resistance with ablation threshold of 0.24 J/cm 2 , and preferable hydrophobicity with water contact angle of 150°. Finally, the infrared detection measurements through the optical window express that the ASA on the ZnS window effectively improves the target details well and suppresses the background noise of the captured infrared image.
Cicada wing exhibiting a high transparency at wide viewing angles can be bioinspired for the formation of antireflective subwavelength array (ASA), which can effectively enhance surface transmittance of infrared window for infrared detection. Due to extreme fine structure of the ASA and significant limitations of single pulse Gaussian beam manufacturing accuracy, it still a challenge to fabricate ASA with broadband and mechanically-durable properties by femtosecond laser. In this study, a novel temporal-spatial shaping femtosecond laser micromachining is proposed to fabricate inverted cone pattern ASA on zinc sulfide (ZnS) substrate for suppressing surface Fresnel reflection and realizing high infrared transmittance. Femtosecond laser double-pulse Bessel beam is used to experimentally fabricate the ASA with tunable depth and width by laser power and pulse delay. The bioinspired ASA is manufactured on ZnS, achieving high transmittance of 88 % in the wavelength of 4–12 μm, good laser damage resistance with ablation threshold of 0.24 J/cm 2 , and preferable hydrophobicity with water contact angle of 150°. Finally, the infrared detection measurements through the optical window express that the ASA on the ZnS window effectively improves the target details well and suppresses the background noise of the captured infrared image.
期刊：
Journal of Materials Engineering and Performance,2025年:1-13 ISSN：1059-9495
通讯作者：
Wang, Liqiang;Fan, XF
作者机构：
[Fan, Xiangfang; Wang, Liqiang] Univ South China, Coll Mech Engn, Hengyang 421100, Peoples R China.;[Zhao, Jianming] Hengyang Valin Steel Tube Co, Hengyang 421000, Peoples R China.
通讯机构：
[Fan, XF ; Wang, LQ] U;Univ South China, Coll Mech Engn, Hengyang 421100, Peoples R China.
关键词：
energy density;H13 steel;hardness;high-temperature wear resistance;laser remelting;laser transformation hardening
摘要：
This paper presents the results of a study on the laser remelting and laser transformation hardening of mandrel H13 steel (quenched and tempered) for a tube rolling mill. The surface of the specimens was irradiated with a continuous high-power fibre laser (RFL-C3300) with a spot size of 12 mm × 2 mm. A comparison of the morphological organisation, microhardness and high-temperature wear resistance of the laser-remelted and laser-phase-change-hardened specimens was carried out to investigate the effect of laser process parameters on the organisation and properties of H13 steel. The results show that the laser-remelted specimens had a better hardening effect and wear resistance at the same power. The solidification organisation of the laser-remelted specimens was mainly in the form of fine equiaxed cells and columnar cells, and the martensite in the phase-change-hardened zone was fine and dense. The microhardness of the surface of the laser-remelted specimens was up to 794.0 HV0.2, which is about 2.6 times higher than that of the substrate. The coefficient of friction and the amount of wear were as low as 0.39 and 0.1221 mm3, respectively, and the wear mechanism was mainly abrasive wear.
关键词：
Uranium reduction;Cobalt oxides;Oxygen vacancies;Recovery of uranium;Radioactive wastewater
摘要：
As the primary uranium species in aquatic systems, uranyl ions (UO 2 2+ ) readily form stable coordination complexes with organic contaminants, severely compromising the recovery and utilization of uranium. To address this challenge, we developed a novel photoelectrochemical (PEC) system featuring oxygen-vacancy-enriched cobalt oxide-modified carbon felt (OvCoO x /CF) as a functional cathode. In this PEC system, the photoanode is photoexcited to generate holes (h + ) and hydroxyl radicals (•OH) efficiently decomposing organic substances, thereby releasing uranium from complexes. Concurrently, photogenerated electrons migrate through the external circuit to the OvCoO x /CF cathode, where they reduce and fix the released UO 2 2+ into stable uranium compounds while simultaneously generating electrical output. This synergistic mechanism enables the system to achieve remarkable enhancements in contaminant removal efficiency, with substantial increases in rate constants ( k ) for both uranium reduction and organic degradation. The exceptional uranium extraction performance is primarily attributed to abundant active sites, the lower adsorption energy of UO 2 2+ , and the rapid electron transfer channel introduced by the incorporation of Ov. Notably, the PEC system maintains high efficiency across diverse conditions, including pH fluctuations, high salinity and various organic contaminant species and concentrations. Furthermore, its operational robustness extends to challenging environments such as polluted seawater and natural sunlight exposure. This work establishes a sustainable paradigm for radioactive wastewater remediation, integrating efficient uranium extraction with organic pollutant elimination and in situ electricity generation, offering a transformative solution for nuclear resource recovery and environmental protection.
As the primary uranium species in aquatic systems, uranyl ions (UO 2 2+ ) readily form stable coordination complexes with organic contaminants, severely compromising the recovery and utilization of uranium. To address this challenge, we developed a novel photoelectrochemical (PEC) system featuring oxygen-vacancy-enriched cobalt oxide-modified carbon felt (OvCoO x /CF) as a functional cathode. In this PEC system, the photoanode is photoexcited to generate holes (h + ) and hydroxyl radicals (•OH) efficiently decomposing organic substances, thereby releasing uranium from complexes. Concurrently, photogenerated electrons migrate through the external circuit to the OvCoO x /CF cathode, where they reduce and fix the released UO 2 2+ into stable uranium compounds while simultaneously generating electrical output. This synergistic mechanism enables the system to achieve remarkable enhancements in contaminant removal efficiency, with substantial increases in rate constants ( k ) for both uranium reduction and organic degradation. The exceptional uranium extraction performance is primarily attributed to abundant active sites, the lower adsorption energy of UO 2 2+ , and the rapid electron transfer channel introduced by the incorporation of Ov. Notably, the PEC system maintains high efficiency across diverse conditions, including pH fluctuations, high salinity and various organic contaminant species and concentrations. Furthermore, its operational robustness extends to challenging environments such as polluted seawater and natural sunlight exposure. This work establishes a sustainable paradigm for radioactive wastewater remediation, integrating efficient uranium extraction with organic pollutant elimination and in situ electricity generation, offering a transformative solution for nuclear resource recovery and environmental protection.
期刊：
Journal of Cranio-Maxillofacial Surgery,2025年53(5):576-589 ISSN：1010-5182
通讯作者：
Chen, J
作者机构：
[Qiu, Xiaohui] Cent South Univ, Xiangya Hosp, Natl Clin Res Ctr Geriatr Disorders, Changsha, Peoples R China.;[Chen, Jing] Cent South Univ, Xiangya Hosp, Dept Neurosurg, Changsha, Peoples R China.;[Zhou, Jianda; Qiu, Xiaohui; Zhong, Chi] Cent South Univ, Xiangya Hosp 3, Dept Plast & Reconstruct Surg, Changsha, Peoples R China.;[Chen, Qiuyang; Liao, Shenghui] Cent South Univ, Sch Comp Sci, Changsha, Peoples R China.;[Yang, Tong; Zhao, Yingchao] Univ South China, Sch Mech Engn, Hengyang, Peoples R China.
通讯机构：
[Chen, J ] C;Cent South Univ, Xiangya Hosp, Dept Neurosurg, Changsha, Peoples R China.
关键词：
Artificial intelligence;CT big dataset;Surgical design
摘要：
Background The morphology of the zygomatic complex significantly influences facial appearance, leading to a focus on zygomatic osteotomy. The current technique, the “L-shaped” zygomatic osteotomy, requires a small incision and preoperative osteotomy design for an osteotomy guide. However, the use of multiple software programs in the design process makes it time-consuming and clinically challenging.
The morphology of the zygomatic complex significantly influences facial appearance, leading to a focus on zygomatic osteotomy. The current technique, the “L-shaped” zygomatic osteotomy, requires a small incision and preoperative osteotomy design for an osteotomy guide. However, the use of multiple software programs in the design process makes it time-consuming and clinically challenging.
Method Artificial intelligence technology offers a solution by integrating digital medical technology into medicine. AI algorithms were developed based on point cloud models, using 2000 cases of three-dimensional CT data for training. Eighty CT data sets were randomly chosen for both AI and manual skull segmentation designs. The effectiveness, symmetry, safety, and aesthetic outcomes were compared.
Artificial intelligence technology offers a solution by integrating digital medical technology into medicine. AI algorithms were developed based on point cloud models, using 2000 cases of three-dimensional CT data for training. Eighty CT data sets were randomly chosen for both AI and manual skull segmentation designs. The effectiveness, symmetry, safety, and aesthetic outcomes were compared.
Result The AI zygomatic osteotomy showed superior performance in symmetry and aesthetics compared to manual zygomatic osteotomy. The complex structure of the zygomatic arch highlights the advantages of AI-driven osteotomy design, especially in intricate cases. Additionally, the AI osteotomy scheme demonstrated no compromise in safety indicators compared to the manual approach.
The AI zygomatic osteotomy showed superior performance in symmetry and aesthetics compared to manual zygomatic osteotomy. The complex structure of the zygomatic arch highlights the advantages of AI-driven osteotomy design, especially in intricate cases. Additionally, the AI osteotomy scheme demonstrated no compromise in safety indicators compared to the manual approach.
Conclusion AI zygomatic osteotomy proves to be a safe and effective alternative to manual zygomatic osteotomy, showcasing enhanced symmetry and aesthetic outcomes. The efficiency and precision of AI-driven design in complex zygomatic osteotomies make it a promising advancement in this field.
AI zygomatic osteotomy proves to be a safe and effective alternative to manual zygomatic osteotomy, showcasing enhanced symmetry and aesthetic outcomes. The efficiency and precision of AI-driven design in complex zygomatic osteotomies make it a promising advancement in this field.
摘要：
Concrete pumping technology is widely applied in the construction industry, especially in high-rise buildings and large-span bridges. However, during the actual pumping, concrete may bleed or get segregated, leading to the blockage of a pipe. In order to improve the pumping efficiency and reduce the blockage risk, the flow of fresh concrete with a single-size coarse aggregate(CA) in pipe was simulated, and the effects of size and shape, and volume fraction of CA on the pipe blockage were studied using a Computational Fluid Dynamics-Discrete Element Method (CFD-DEM) coupling method. The flow velocity, pressure distribution and flow state during the concrete pumping process were also analyzed for in-depth understanding of the flow behavior of concrete in the pumping pipe. It was proposed to use the peak pressure on the pumping pipe to characterize the risk of pipe blockage. The cause of pipe blockage formation was analyzed by tracking the movement law, mass and velocity distribution of CA. The obtained results show that local accumulation of CA at the peak pressure position can increase its concentration and decrease the average velocity, causing the peak pressure to rise and increasing the risk of pipe blockage. The risk of pipe blockage increases gradually with increasing size of CA. The most prone blockage takes place at the bend and shifts downward with increasing size of CA. The shape of CA has a lesser impact on the location of the blockage. However, as the shape changes from spherical to ellipsoidal to flaky, the peak pressure gradually increases, thus raising the risk of blockage. With increasing volume fraction of CA, the peak pressure also increases. In order to reduce the risk of pipe blockage, it is recommended that the size of CA should be less than 20 mm, the volume fraction should be no more than 30 %, and the shape should be spherical or ellipsoidal as far as possible.
Concrete pumping technology is widely applied in the construction industry, especially in high-rise buildings and large-span bridges. However, during the actual pumping, concrete may bleed or get segregated, leading to the blockage of a pipe. In order to improve the pumping efficiency and reduce the blockage risk, the flow of fresh concrete with a single-size coarse aggregate(CA) in pipe was simulated, and the effects of size and shape, and volume fraction of CA on the pipe blockage were studied using a Computational Fluid Dynamics-Discrete Element Method (CFD-DEM) coupling method. The flow velocity, pressure distribution and flow state during the concrete pumping process were also analyzed for in-depth understanding of the flow behavior of concrete in the pumping pipe. It was proposed to use the peak pressure on the pumping pipe to characterize the risk of pipe blockage. The cause of pipe blockage formation was analyzed by tracking the movement law, mass and velocity distribution of CA. The obtained results show that local accumulation of CA at the peak pressure position can increase its concentration and decrease the average velocity, causing the peak pressure to rise and increasing the risk of pipe blockage. The risk of pipe blockage increases gradually with increasing size of CA. The most prone blockage takes place at the bend and shifts downward with increasing size of CA. The shape of CA has a lesser impact on the location of the blockage. However, as the shape changes from spherical to ellipsoidal to flaky, the peak pressure gradually increases, thus raising the risk of blockage. With increasing volume fraction of CA, the peak pressure also increases. In order to reduce the risk of pipe blockage, it is recommended that the size of CA should be less than 20 mm, the volume fraction should be no more than 30 %, and the shape should be spherical or ellipsoidal as far as possible.
摘要：
This paper thoroughly introduces the one-stop decontamination and reuse process specific to radioactively contaminated steel, highlighting its key characteristics. By leveraging the data from engineering practice, we conduct a detailed analysis of the effectiveness of various decontamination techniques, including crystalline phase temperature difference gradient decontamination, strippable film decontamination, as well as a novel decontamination agent and its corresponding process. Additionally, we explore the properties of the steel products obtained after melting. It is concluded that this one-stop decontamination and reuse process, supported by advanced technologies, realizes the recycling of radioactively contaminated steel.
This paper thoroughly introduces the one-stop decontamination and reuse process specific to radioactively contaminated steel, highlighting its key characteristics. By leveraging the data from engineering practice, we conduct a detailed analysis of the effectiveness of various decontamination techniques, including crystalline phase temperature difference gradient decontamination, strippable film decontamination, as well as a novel decontamination agent and its corresponding process. Additionally, we explore the properties of the steel products obtained after melting. It is concluded that this one-stop decontamination and reuse process, supported by advanced technologies, realizes the recycling of radioactively contaminated steel.
