通讯机构：
[Zhu, HM ] U;Univ South China, Sch Mech Engn, Hengyang 421001, Hunan, Peoples R China.;Hunan Prov Key Lab Adv Laser Mfg Technol, Hengyang 421001, Hunan, Peoples R China.
关键词：
distortion;laser repairing;microstructure;properties;scanning strategy;temperature distribution
摘要：
In order to explore the effects of scanning strategies on the distortion and properties of laser-repaired thin-plate components, four commonly used strategies, including continuous raster scanning strategy, continuous orthogonal scanning strategy (COS), subarea W-type scanning strategy and subarea leap-type scanning strategy, were applied for laser-repairing thin-plate 2Cr13 steel. The finite element simulation and experimental results show that the temperature field of the laser-repaired layer prepared by COS exhibits symmetrical elliptical characteristic, with homogeneous temperature gradient along all directions. Consequently, the outermost of COS sample exhibits the smallest deformation of 2.86 mm, by avoiding both the unidirectional shrinkage of molten pool and the cumulative effect of longitudinal stress. In contrast, much larger distortion was produced by the other three scanning strategies due to the uneven temperature gradient. Dense martensite without defects was achieved by continuous scanning, while the coarsen martensite occurred by using subarea scanning. The repaired layer by using subarea scanning exhibits lower microhardness of 585-590 HV0.2 and poor wear resistance of 1.45 x 10-5-1.48 x 10-5 mm3/N m, in comparison to 613-618 HV0.2 and 0.9 x 10-5-0.92 x 10-5 mm3/N m obtained by using continuous strategy. COS is the most ideal strategy in laser-repairing thin-plate 2Cr13 steel in this work, exhibiting the lowest distortion as well as the highest microhardness and wear resistance.
摘要：
Diffusion study of the Ni-Si-V system is significant for the establishment of kinetic database of Ni-based alloys. In this work, the diffusion couple experiment combined with the numerical inverse method was adopted to evaluate the diffusivities and atomic mobilities for the Ni-Si-V fcc phase with high throughput. We prepared 12 fcc Ni-Si-V diffusion couples, which were annealed at 1273, 1373 and 1473 K, and their composition profiles after annealing were then measured by EPMA (Electron Probe Microanalysis). Subsequently, inputting the measured composition profiles as well as the available thermodynamic descriptions into the numerical inverse method incorporated in the CALTPP (CALculation of ThermoPhysical Properties) software, the composition- and temperature-dependent diffusivities and atomic mobilities for the Ni-Si-V fcc phase were simultaneously evaluated. In order to verify the reliability of the present evaluations, the CALTPP-simulated diffusion behaviors such as composition profiles and diffusion paths were compared with the measured ones, demonstrating reasonable agreements with each other. Meanwhile, the high-throughput determinations of diffusivities were confirmed by the ones obtained by the Matano-Kirkaldy method. Furthermore, applying the presently obtained diffusivities and atomic mobilities in combination with thermodynamic descriptions of the Ni-Si-V fcc phase, their diffusion flux, two-dimensional composition profile, activation energy and pre-frequency factor were predicted. It is expected that the presently obtained diffusivities and atomic mobilities of the Ni-Si-V fcc phase can contribute to the establishment of kinetic database of Ni-based alloys for their high-efficiency material design.
关键词：
Ti alloys;surface nitriding;microhardness;wear resistance;high-temperature oxidation resistance
摘要：
Titanium alloys are considered lightweight alloys and are widely applied across various industries. However, their low hardness, poor wear resistance, and limited oxidation resistance restrict their prospects for wider application. In this paper, nitride coatings were prepared using three preparation processes, namely laser surface nitriding (LSN), physical vapor deposition (PVD), and plasma ion implantation (PII). Their microstructure, microhardness, tribological behavior, and high-temperature oxidation characteristics were compared. The experimental results revealed that nitrided coatings were successfully prepared using the three methods. However, a comparison of these data shows that the LSN coating exhibited superior comprehensive performance. It achieved the maximum thickness within the shortest preparation time: the thickness was about 280 mu m and the deposition rate of the LSN method was 2250 and 90,000 times higher than those of the PVD and PII methods. Nitrides have high hardness, but the carrying capacity could be attributed to the thickness of the coatings: the PVD coating could withstand a force of 500 g, while the PII coating only withstood a force of less than 25 g. In addition, as hardness is the most important factor for excellent wear resistance, the average volumetric wear rate of the LSN and PVD coatings was about 9 x 10-6 mm3/m center dot N, and their relative wear resistance was 49.2 times that of Ti6Al4V. Meanwhile, the excellent bond between the LSN coating and the substrate was evidenced by a high-temperature oxidation test during a rapid heating-cooling cycle.
摘要：
An innovative MnO/Ti3C2 MXene heterostructure, consisting of three-dimensional (3D) MnO nanosheet array directly assembled on two-dimensional (2D) Ti3C2 MXene nanosheets, was synthesized via a simple hydrothermal-annealing strategy for uranium elimination. This unique 3D/2D heterostructure derived substantially high specific surface area (311.9 m2/g) and exposed considerable amount of surface oxygen groups, including surface lattice M-O and adsorbed -OH. Through a comprehensive exploration encompassing adsorbent dosage, pH, ionic strength, initial U(VI) concentration, and environmental conditions, the MnO/Ti3C2 MXene heterostructure demonstrated an extraordinary proficiency and specificity in the removal of U(VI). This composite exhibited an outstanding adsorption capacity of 862.1 mg/g, with a removal efficiency of 99.7 % and rapid kinetics (above 90 % within 20 s). The kinetic study indicated the adsorption process followed chemisorption dynamics and single -layer adsorption behavior. Comprehensive analyses validated the structural integrity and confirmed the successful uranium adsorption via strong interaction between UO22+ and surface unsaturated oxygen groups. Notably, the MnO/Ti3C2 MXene maintained excellent recyclability, highlighting its potential for large-scale applications. It emerges as a promising candidate for uranium removal, offering insights for optimizing composite materials in diverse environmental conditions and fostering advancements in water purification technologies.
期刊：
Journal of Materials Chemistry A,2024年12(6):3331-3339 ISSN：2050-7488
通讯作者：
Ju, J;Qian, XT
作者机构：
[Huang, Chenhui; Kang, Xiaomin; Zhang, Meng] Univ South China, Coll Mech Engn, Hengyang 421001, Peoples R China.;[Zhai, Zhaofeng] Chinese Acad Sci, Inst Met Res, Shenyang 110012, Peoples R China.;[Ju, Jiang] City Univ Hong Kong, Ctr Adv Nucl Safety & Sustainable Dev, Hong Kong 999077, Peoples R China.;[Qian, Xitang; Qian, XT] Hong Kong Univ Sci & Technol, Dept Chem & Biol Engn, Kowloon, Hong Kong, Peoples R China.
通讯机构：
[Qian, XT ] H;[Ju, J ] C;City Univ Hong Kong, Ctr Adv Nucl Safety & Sustainable Dev, Hong Kong 999077, Peoples R China.;Hong Kong Univ Sci & Technol, Dept Chem & Biol Engn, Kowloon, Hong Kong, Peoples R China.
摘要：
Nanofluidic ion regulation membranes have emerged as versatile platforms for applications in molecular/ion separation and energy conversion. The use of two-dimensional (2D) material-based membranes holds great potential for the regulation of nanofluidic ions owing to their unique properties of surface charges, nanochannels, and nanocapillary force. Herein, a class of 2D flexible ion-conductive membranes with surface charge-controllable and voltage-tunable ion transport properties, which are assembled with monolayered Cd vacancy-containing CdPS3 (vc-CdPS3)-based nanosheets, is reported. Importantly, the ion conductivity of the vc-CdPS3 membrane is several orders of magnitude higher than that of bulk salt solutions up to 0.1 M and reaches a plateau of similar to 10 mS cm(-1) in low concentrated solution (<= 1 mM), demonstrating typical charge-controllable nanofluidic ion transport behavior. This membrane exhibits excellent stability and maintains an ion conductivity of 23 and 20 mS cm(-1) under harsh acidic and alkaline conditions, respectively. By applying positive/negative gating voltage, ion transportation within the vc-CdPS3 membrane is tuned, resulting in low/high ion conductivity. The voltage-tunable behavior across a broad spectrum of cations with varying sizes and charges is observed, showcasing the ion-specific switch ratios of 12 and 10 for potassium and sodium ions, respectively, under an applied voltage of 2 V/-2 V. This work demonstrates the potential of vacancy-containing membranes for a variety of membrane separation applications and offer a strategy for preparing efficient ion transport devices.
期刊：
Physica Status Solidi-Rapid Research Letters,2024年18(2):2300334- ISSN：1862-6254
通讯作者：
Huo, SY
作者机构：
[Fu, Chun-Ming; Li, Hong-Kang; Huo, Shao-Yong; Yao, Long-Chao] Univ South China, Coll Mech Engn, Hengyang 421001, Peoples R China.
通讯机构：
[Huo, SY ] U;Univ South China, Coll Mech Engn, Hengyang 421001, Peoples R China.
关键词：
defect states;elastic valley edge states;power dividers;rainbow trapping;topological phononic crystals
摘要：
Topological phononic crystals (PnCs) with topologically protected boundary states have important applications in the fields of acoustic wave transmission and control. However, previous studies based on solid-state PnC systems are mostly limited by fixed structures, resulting in the difficulty to deform the edge states, which partly limits its practical applications. Herein, a 2D solid topological PnC coupled with the defect is designed to achieve the adjustable valley edge state and rainbow trapping. First, by breaking the spatial inversion symmetry, the valley Hall phase transition of elastic wave is realized and valley edge states are obtained. Next, by introducing defects of different widths between the two different valleys' topological PnCs, both the defect-adjusted valley edge state and defect state are achieved. Then, by designing different topological PnCs waveguides, the robust transport characteristics of the two above states are compared. Subsequently, a new power divider based on the defect-adjusted valley edge state is designed, which is found to possess various manners of operation such as equal and unequal power divisions. Finally, based on defect adjustment of the edge states, a rainbow trapping is implemented. This research provides an important guidance for ultrasonic devices, such as waveguides, energy harvesters, and power dividers. By introducing the line defects in the topological domain wall for the elastic wave, the defect-adjusted valley edge states and defect states are presented, which further are applied to design the novel elastic ultrasonic devices, such as the equal or unequal power dividers and the rainbow trapping effects.image & COPY; 2023 WILEY-VCH GmbH
摘要：
Mining can provide abundant resources, but it also causes heavy metal wastewater pollution, which poses a serious threat to aquatic ecosystems. In this study, Cypridopsis vidua was used as the test organism to investigate the single and combined acute toxicity of common heavy metals (such as chromium (Cr) and nickel (Ni)) in mining wastewater. Then, a random forest model (RF model) was used to predict the combined toxicity of chromium and nickel. Single acute toxicity experiments showed that the 96 h-LC(50 )values of the Cr and Ni for Cypridopsis vidua were 0.81 mg/L and 4.3 mg/L, respectively. aCr was more toxic than Ni. Furthermore, the combined acute toxicity experiments demonstrated that the toxicity of Cr-Ni was higher than Ni but lower than Cr. The predicted results of the RF model were highly consistent with the experimental results of the Cr-Ni combined acute toxicity. So, the model has accurate toxicity prediction ability.
摘要：
Commercially pure titanium (CP-Ti) took advantages of low stiffness, high corrosion resistance and biocompatibility, implying an ideal structural material in aerospace, military and medical industries. However, its insufficient mechanical properties have always been the long-standing obstacle for the industrial applications. In this work, we have achieved a superior strong and ductile CP-Ti via active atmosphere -assisted selective laser melting (SLM) and subsequent rolling treatment. By incorporating the active N2 atmosphere during SLM, mechanical properties of CP-Ti were substantially improved, microhardness of the lyaers with 10 at.% and 100 at.% was 63 % and 174.3 % higher than that of CP-Ti with 182.3 HV0.2, the compressive strength of 10 sample was 27.1 % higher than that of 10 L sample when the strain was 52.2 %, and ultimate tensile strength of 10 sample reached 928 MPa with an elongation of 25.6 %, and ultimate tensile strength and elongation of 10 L sample were enhanced simultaneously by 58.3 % and 13.6 % relative to CP-Ti sample. These were attributed to the interstitial strengthening induced by N atoms. After rolling treatment, the mechanical properties of N -doping layers could enhance furtherly. Macroscale cracking along the rolling direction never occur in the 10 L sample during the repeatedly rolling treatment, which could depend to high tolerability of sandwich layers for high -density dislocations. Meanwhile, rolling treatment played an important role for refining grain to enhance the strength further.
作者机构：
[Chen, Nan; Yuan, Tie-chui; Li, Zhi-you] Cent South Univ, State Key Lab Powder Met, Changsha 410083, Peoples R China.;[Teng, Hao; Chen, Long-wei] Univ South China, Coll Mech Engn, Hengyang 421001, Peoples R China.
通讯机构：
[Li, ZY ] C;[Teng, H ] U;Cent South Univ, State Key Lab Powder Met, Changsha 410083, Peoples R China.;Univ South China, Coll Mech Engn, Hengyang 421001, Peoples R China.
摘要：
With high-energy wet ball milling M2 high-speed steel (HSS) powder and ferrovanadium alloy, an in-situ synthesized core-shell MC carbides reinforced M2 HSS was prepared via vacuum sintering. The phase, morphology and composition distribution of the milled composite powders, and the evolution of the sintered microstructure with the temperature and the associated mechanical properties before and after heat treatment were investigated. The ground powders were fully refined into lamellae and aggregates with V-element evenly distributed inside. Almost full densification (similar to 99.2% relative density) of the modified M2 steel was achieved at 1180 degree celsius by supersolidus liquid phase sintering. Near-spherical MC carbides and irregular M6C carbides were dispersed within the HSS matrix, and the MC developed a core-shell structure due to the solidification of the sintering liquid. Both the matrix grains and carbides of the sintered alloy had been refined by heat treatment, reaching satisfactory bending strength of 3580 MPa and hardness of HRC58, and enhancing the scratch resistance significantly.
作者机构：
[Yu, Miao; Guo, Xin; Zhang, Kai] Sichuan Univ, Sch Mech Engn, Chengdu 610065, Peoples R China.;[Yu, Miao; Guo, Xin; Zhang, Kai] Sichuan Univ, Yibin Ind Technol Res Inst, Yibin 644000, Peoples R China.;[Kang, Xiaomin] Univ South China, Sch Mech Engn, Hengyang 421001, Peoples R China.;[Zhang, Song] Moutai Inst, Dept Food Sci & Engn, Renhuai 564502, Guizhou, Peoples R China.;[Qian, Lu; Qian, L] South China Univ Technol, Sch Mat Sci & Engn, Guangzhou 510641, Peoples R China.
通讯机构：
[Zhang, S ] M;[Qian, L ] S;Moutai Inst, Dept Food Sci & Engn, Renhuai 564502, Guizhou, Peoples R China.;South China Univ Technol, Sch Mat Sci & Engn, Guangzhou 510641, Peoples R China.
摘要：
Hyaluronic acid (HA), a vital glycosaminoglycan in living organisms, possesses remarkable mechanical and viscoelastic properties that have garnered significant attention in therapeutic, biomedical, and cosmetic applications. However, a comprehensive picture of the physicochemical and biocharacterization of HA at the single-molecule level remains elusive. In this work, atomic force microscopy (AFM)-based single-molecule force spectroscopy (SMFS) and molecular dynamics (MD) simulation were used to investigate the nanomechanics and water retention properties of HA at the single-molecule level. The present study aims to unravel the intricate details of the influence of molecular structure on HA behavior and shed light on its unique attributes. According to the force measurements, the energy used to stretch a HA chain in water is 8.45 kJ/mol, significantly surpassing that of Curdlan (3.45 kJ/mol) and chitin (2.23 kJ/mol), both of which possess molecular structures partially similar to that of HA. Intriguingly, the strength of the intrachain interaction of HA (5.54 kJ/mol) was considerably weaker compared to Curdlan (11.06 kJ/mol) and chitin (or cellulose, 10.76 kJ/mol). This result indicates that HA exhibits a preference for interacting with water rather than with itself, thereby showing enhanced water affinity. Moreover, the force measurements demonstrated that changing the glycosidic bond from β-(1-3) (Curdlan) or β-(1-4) (chitin or cellulose) to β-(1-3) + β-(1-4) (HA) resulted in polysaccharides displaying improved water affinity and more extended conformation. These conclusions were further verified by molecular dynamics (MD) simulations. Overall, our work sheds new light on the nanomechanics and water retention properties of HA at the single-molecule level, offering valuable insights for future research in this field.
摘要：
The coating of mesoporous silica nanoshells can improve the stability of gold nanorods while improving the corresponding drug‐carrying capacity. Mesoporous silica coated gold nanorod (GNR@MSN) provides the opportunity to integrate different treatments into a single nanoplatform combining cancer treatment with real‐time diagnosis. This review discusses the advancements of GNR@MSN in synthetic process, bio‐imaging techniques and tumor therapy. Abstract For unique surface plasmon absorption and fluorescence characteristics, gold nanorods have been developed and widely employed in the biomedical field. However, limitations still exist due their low specific surface area, instability and tendency agglomerate in cytoplasm. Mesoporous silica materials have been broadly applied in field of catalysts, adsorbents, nanoreactors, and drug carriers due to its unique mesoporous structure, highly comparative surface area, good stability and biocompatibility. Therefore, coating gold nanorods with a dendritic mesopore channels can effectively prevent particle agglomeration, while increasing the specific surface area and drug loading efficiency. This review discusses the advancements of GNR@MSN in synthetic process, bio‐imaging technique and tumor therapy. Additionally, the further application of GNR@MSN in imaging‐guided treatment modalities is explored, while its promising superior application prospect is highlighted. Finally, the issues related to in vivo studies are critically examined for facilitating the transition of this promising nanoplatform into clinical trials.
通讯机构：
[Qiu, CJ ] U;Univ South China, Sch Mech Engn, Hengyang 421001, Peoples R China.
关键词：
Nickel -based superalloys;Alloy design;Laser directed energy deposition;Mechanical properties
摘要：
The high cracking susceptibility is the major obstacle to the wide application of high gamma '-phase nickel -based superalloys in additive manufacturing. It is especially important to explore the effects of alloying elements during the nickel -based superalloys and establish a new alloy design criterion. In this work, a new nickel -based superalloys with crack -free and low porosity was fabricated by adjusting the content of solid -solution and precipitating elements of Inconel 738LC (IN738LC) alloy utilizing laser directed energy deposition (LDED) technology, achieving an increase in strength and ductility simultaneously. The newly developed nickel -based superalloys maintain a high content of gamma '-phase and display substantial fine bulk MC carbides, resulting in higher strength (UTS: 1461 MPa, YS: 1105 MPa) and elongation (EL: 12.9%). After heat treatment, extensive long -stripes of M23C6 carbides were detected in the IN738LC sample, which led to poor tensile properties at high temperature (900 degrees C). However, due to the finer gamma ' phase uniformly distributed in the matrix, the developed new nickel -based superalloys exhibits optimal tensile properties (UTS: 593 MPa, YS: 475 MPa) and ductility (9.4%) at 900 degrees C. This approach can provide guidance for the design of high gamma '-phase nickel -based superalloys for additive manufacturing starting from elemental powders.
作者：
Su, Chi;Hua, Yilong;Liu, Yi;Tao, Shu;Jia, Fei;...
期刊：
PLOS ONE,2024年19(3):e0300800 ISSN：1932-6203
通讯作者：
Lin, WY
作者机构：
[Hua, Yilong; Liu, Yi; Su, Chi; Zhao, Wenhui] Univ South China, Sch Resources Environm & Safety Engn, Hengyang 421001, Peoples R China.;[Tao, Shu] Univ South China, Sch Math & Phys, Hengyang, Peoples R China.;[Jia, Fei] Univ South China, Sch Civil Engn, Hengyang, Peoples R China.;[Zhao, Wenhui] Shanxi Prov Changzhi City Wuxiang Cty Jia Huo Town, Changzhi, Peoples R China.;[Lin, WY; Lin, Wangyang] Univ South China, Coll Mech Engn, Hengyang, Peoples R China.
通讯机构：
[Lin, WY ] U;Univ South China, Coll Mech Engn, Hengyang, Peoples R China.
摘要：
Mining wastewater with heavy metals poses a serious threat to the ecological environment. However, the acute single and combined ecological effects of heavy metals, such as chromium (Cr) and nickel (Ni), on freshwater ostracods, and the development of relevant prediction models, remain poorly understood. In this study, Heterocypris sp. was chosen to investigate the single and combined acute toxicity of Cr and Ni. Then, the quantitative structure-activity relationship (QSAR) model was used to predict the combined toxicity of Cr and Ni. The single acute toxicity experiments revealed high toxicity for both Cr and Ni. In addition, Cr exhibited greater toxicity compared to Ni, as evidenced by its lower 96-hour half-lethal concentration (LC50) of 1.07 mg/L compared to 4.7 mg/L for Ni. Furthermore, the combined acute toxicity experiments showed that the toxicity of Cr-Ni was higher than Ni but lower than Cr. Compared with the concentration addition (CA) and independent action (IA) models, the predicted results of the QSAR model were more consistent with the experimental results for the Cr-Ni combined acute toxicity. So, the high accuracy of QSAR model identified its feasibility to predict the toxicity of heavy metal pollutants in mining wastewater.
通讯机构：
[Xu, SL ] U;Univ South China, Sch Resource Environm & Safety Engn, 28,West Changsheng Rd, Hengyang 421001, Peoples R China.;Univ South China, Prov Key Lab Emergency Safety Technol & Equipment, Hengyang 421001, Peoples R China.
关键词：
robot;radiation;reinforcement;gamma-ray;superMC;control and sensing systems
摘要：
This study investigates the radiation damage and radiation reinforcement of the control and sensing systems of nuclear robots. Radiation experiments were conducted on key electronic devices to study their radiation resistance, and a shielding structure for radiation reinforcement was designed to meet the radiation resistance performance requirements of the system. The results show that at doses exceeding 1300 Gy, Hall sensors, pressure transducers, and temperature transducers exhibit radiation damage. At doses exceeding 170 Gy, transformers and controllers also show radiation damage. Lithium batteries remain largely unaffected, but packs experience voltage decline. When using Pb and W as shielding materials for Super MC simulation, it was found that at a thickness of 15 mm, the shielding efficiency of the controller and transformer under Pb shielding increased by approximately 84.99% and 52.00%, respectively, compared to 92.23% and 74.47% under W, which had the best shielding effect benefits. By adopting radiation-resistant shielding reinforcement, we can effectively improve the radiation resistance of the controller and transformer. This is crucial for ensuring the reliable operation of nuclear robots in high-radiation environments and providing important data and theoretical support for the development of related technologies.
期刊：
Virtual and Physical Prototyping,2024年19(1) ISSN：1745-2759
通讯作者：
Bai, XW
作者机构：
[Bai, Xingwang; Xi, Shengxuan; Dong, Honghui; Liu, Mengru] Univ South China, Sch Mech Engn, Hengyang, Peoples R China.;[Li, Runsheng] China Univ Petr East China, Coll Mech & Elect Engn, Qingdao, Peoples R China.;[Zhang, Haiou] Huazhong Univ Sci & Technol, Sch Mech Sci & Engn, Wuhan, Peoples R China.;[Zhou, Xiangman] China Three Gorges Univ, Coll Mech & Power Engn China, Yichang, Peoples R China.
通讯机构：
[Bai, XW ] U;Univ South China, Sch Mech Engn, Hengyang, Peoples R China.
关键词：
Wire and arc additive manufacturing;3D point cloud;defect detection;surface curvature
摘要：
Wire and Arc Additive Manufacturing (WAAM) with high efficiency and low-cost is an economical choice for the rapid fabrication of medium-to-large-sized metallic components and has attracted great attention from scholars and entrepreneurs in recent years. However, defects such as porosity, and humps, could occur occasionally after each layer of deposition on weld bead surfaces due to disturbances and process abnormities. Detection and quantitative evaluation of weld bead defects is crucial to ensure successful deposition and the quality of the entire component. In this paper, a novel defect detection and evaluation system was developed for WAAM utilizing machine vision technology. The system incorporated new defect detection algorithms based on analysing the 2D curvature of the weld bead height curve and the 3D curvature of the weld bead point cloud. Furthermore, a defect evaluation algorithm was developed based on reconstructing the normal weld bead contour using geometric features extracted from the accumulated point cloud. This system enables the automatic detection of weld bead morphology during the WAAM process, offering important information about the location, type, and volume of defects for effective interlayer repairs and enhanced part quality.
期刊：
International Journal of Heat and Mass Transfer,2024年218 ISSN：0017-9310
通讯作者：
Zhou, XM
作者机构：
[Fu, Junjian; Tian, Qihua; Zhou, Xiangman; Zhou, Xing; Fu, Zichuan] China Three Gorges Univ, Coll Mech & Power Engn, Yichang 443002, Peoples R China.;[Zhou, Xing] China Three Gorges Univ, Hubei Key Lab Hydroelect Machinery Design & Mainte, Yichang 443002, Peoples R China.;[Bai, Xingwang] Univ South China, Sch Mech Engn, Hengyang 421001, Peoples R China.;[Zhang, Haiou] Huazhong Univ Sci & Technol, State Key Lab Digital Mfg Equipment & Technol, Wuhan 430074, Peoples R China.
通讯机构：
[Zhou, XM ] C;China Three Gorges Univ, Coll Mech & Power Engn, Yichang 443002, Peoples R China.
关键词：
WAAM;External deflection magnetic field;Heat and mass transfer;Numerical simulation;Overlapping flatness
摘要：
During the magnetic controlling wire arc additive manufacturing (WAAM) process, the external magnetic field directly influences the arc shape and the molten pool flow, which can further affect the morphology of the deposition layer and the overlapping flatness. This study introduced an external deflection magnetic field (EDM) with longitudinal and deposition direction components into the WAAM process. A numerical simulation model of the coupling of the arc and the molten pool was established on the basis of a weak coupling method. The numerical simulation model was utilized to investigate the effect of the EDM field on the heat and mass transfer behaviors in the WAAM overlapping deposition process. The results showed that the EDM field generated an additional electromagnetic force in the welding arc and molten pool with circumferential and single-side lateral components. The additional electromagnetic force drove the arc plasma to the rear of the molten pool and the side of the solidified weld bead simultaneously, which resulted in more heat and electromagnetic force concentrated on the gap of the overlapping beads. An asymmetric circumferential rotating vortex appeared in the molten pool, which drove the melted metal to fill the gap of the overlapping beads and improved the overlapping flatness.
摘要：
In this study, a hierarchical Fe2O3-Co3O4 heterojunction with abundant oxygen vacancies was fabricated by a MOF-assisted strategy combing with a thermal treatment process. The morphology, nanostructure and other properties of the synthesized samples were comprehensively investigated by related characterizations. The re-sults display that the Co3O4 modified with Fe2O3 nanorod exhibits an admirable mesoporous structure and abundant oxygen vacancies. In addition, the gas sensing devices were constructed by as-prepared samples and demonstrated that the gas sensor based on Fe2O3-Co3O4 composites shows excellent gas sensitivity of 91.5 to-wards 100 ppm acetone at a working temperature of 200 degrees C, with a short response-recovery time of 20/21 s. Meanwhile, the sensor possesses good reproducibility and long-term stability (over 30 days), and outstanding selectivity towards acetone gas. Exploration into a convincing gas sensing mechanism confirms that fabricating of p-n heterojunction architecture, regulating of oxygen vacancies and designing of mesoporous structure syn-ergistically induced the excellent gas sensing performance. Therefore, this work can offer a promising strategy to enhance acetone sensing response of Fe2O3-Co3O4 in practical applications.
通讯机构：
[Li, ZY ; Liu, YL] U;Univ South China, Coll Mech Engn, Hengyang 421001, Peoples R China.
关键词：
Titanium carbide;Cathode interface layer;Organic solar cells;Power conversion efficiency;Conductivity
摘要：
Poly(9,9-bis(3′-(N,N-dimethyl)-Nethylammonium-propyl-2,7-fluorene)-alt-2,7- (9,9-dioctylfluorene)) dibromide (PFN-Br) has been widely used as an cathode interface layer (CIL) for efficient organic solar cells (OSCs) because of its straightforward solution processability, excellent electron extraction ability, as well as prominent compatibility with various OSCs systems. However, the relatively low conductivity of PFN-Br results in CIL thicknesses usually <10 nm prepared from PFN-Br, which is obviously not conducive to the roll-to-roll large-scale production of OSCs. In this work, titanium carbide (Ti3C2) was doped into the conventional CIL-material PFN-Br to improve the conductivity of PFN-Br, increase the electron extraction of the active layer, as well as optimize the ohmic contact between the CIL and the electrode. As a result, the power conversion efficiency (PCE) was boosted from 14.56 % to 15.80 % for OSCs based on PTzBI-oF:PYF-T-o, from 15.49 % to 17.27 % for OSCs based on PM6:L8-BO and from 17.65 % to 19.12 % for OSCs based on D18:L8-BO. The application of Ti3C2 doping PFN-Br strategy is expected to bring new opportunities for improving the conductivity of high performance CIL, so as to boost the PCE and promote the commercialization of OSCs.
作者机构：
[Li, Ming; Li, Xiao-Hua; Liu, Hong-Ming; Hu, Xiao-Yuan; Qi, Lin-Jing; Zhang, Dong-Meng; Li, XH] Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.;[Liu, Hong-Ming] Fudan Univ, Inst Modern Phys, Shanghai 200433, Peoples R China.;[Li, Xiao-Hua; Li, XH] Univ South China, Natl Exemplary Base Int Sci, Tech Collaborat Nucl Energy & Nucl Safety, Hengyang 421001, Peoples R China.;[Li, Xiao-Hua; Li, XH] Univ South China, Cooperat Innovat Ctr Nucl Fuel Cycle Technol & Eq, Fuel Cycle Technol & Equipment, Hengyang 421001, Peoples R China.;[Li, Xiao-Hua; Li, XH] Hunan Normal Univ, Key Lab Low Dimens Quantum Struct & Quantum Contr, Quantum Control Minist Educ, Changsha 410081, Peoples R China.
通讯机构：
[Li, M; Li, XH ] U;Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.;Univ South China, Natl Exemplary Base Int Sci, Tech Collaborat Nucl Energy & Nucl Safety, Hengyang 421001, Peoples R China.;Univ South China, Cooperat Innovat Ctr Nucl Fuel Cycle Technol & Eq, Fuel Cycle Technol & Equipment, Hengyang 421001, Peoples R China.;Hunan Normal Univ, Key Lab Low Dimens Quantum Struct & Quantum Contr, Quantum Control Minist Educ, Changsha 410081, Peoples R China.
关键词：
proton emission;half-lives;deformed nuclei;Gamow-like model
摘要：
In this study, proton emission half-lives were investigated for deformed proton emitters with based on the presented deformed Gamow-like model, where the deformation effect was included in the Coulomb potential. The experimental half-lives of proton emitters can be reproduced within a factor of 3.45. For comparison, the results from the universal decay law and the new Geiger-Nuttall law are also presented. Furthermore, the relevance of the half-lives to the angular momentum l for La-117, Pr-121, Tb-135, and Ho-141 were analyzed, and the corresponding possible values of l were proposed: l = 3, 3, 4, 4.
期刊：
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing,2024年17:7029-7039 ISSN：1939-1404
通讯作者：
Xia, YZ
作者机构：
[Tang, Xiao; Xiao, Huanlin; Zhang, Jiufeng] Univ South China, Sch Mech Engn, Hengyang 421001, Peoples R China.;[Xia, Yunzhi; Xia, YZ] Univ South China, Sch Elect Engn, Hengyang 421009, Peoples R China.;[Xia, Yunzhi; Xia, YZ] Huazhong Univ Sci & Technol, Sch Cyber Sci & Engn, Wuhan 430074, Peoples R China.
通讯机构：
[Xia, YZ ] U;Univ South China, Sch Elect Engn, Hengyang 421009, Peoples R China.;Huazhong Univ Sci & Technol, Sch Cyber Sci & Engn, Wuhan 430074, Peoples R China.
关键词：
Deep learning;synthetic aperture radar (SAR);target identification;YOLOv7
摘要：
Synthetic aperture radar (SAR) is widely used for ship target detection with the application of deep learning techniques. However, in certain complex environments, such as near shore or with small ships, the problem of false alarms and missed detections still exists. To address these issues, a high-precision ship target detection method named DBW-YOLO, which builds upon YOLOv7-tiny as its foundational network, is proposed in this article. The proposed method consists of the following main steps. First, a feature extraction enhancement network based on deformable convolution network is introduced to obtain more comprehensive feature representations across various ship types. Second, an adaptive feature recognition method based on BiFormer attention mechanism is proposed to strengthen detection accuracy, which is more beneficial to capture near shore ships and small ships. Third, a wise intersection-over-union based on dynamic nonmonotonic focusing mechanism is proposed to generate the loss function, which improves the convergence speed and generalization ability. Consequently, the DBW-YOLO method trains a more robust model that better utilizes samples from near shore and small ships. To verify the effectiveness of this method, two SAR datasets, HRSID and SSDD, are employed for performance evaluation. Compared to other widely-used methods, the mAP value of DBW-YOLO reachs 88.84% and 99.18% on the HRSID and SSDD datasets, respectively. The findings indicate that DBW-YOLO method outperforms other representative SAR ship detection methods in both accuracy and overall performance.
