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Materials Futures 2024年第1期3卷 181-189页

作者： Yanxin Sui Huili Liang Wenxing Huo Xiaozhi zhan Tao Zhu Zengxia mei Songshan Lake Materials Laboratory DongguanGuangdong 523808People’s Republic of China Institute of Physics Chinese Academy of SciencesBeijing 100190People’s Republic of China Department of Biomedical Engineering Tianjin University92 Weijin RoadTianjin 300072People’s Republic of China China Spallation Neutron Source DongguanGuangdong 523803People’s Republic of China

Amorphous Ga_(2)O_(3)(a-Ga_(2)O_(3))has been attracting more and more attention due to its unique merits such as wide bandgap(∼4.9 eV),low growth temperature,large-scale uniformity,low cost and energy efficient,making it a powerful competitor in flexible deep ultraviolet(UV)photodetection.Although the responsivity of the ever-reported a-Ga_(2)O_(3)UV photodetectors(PDs)is usually in the level of hundreds of A/W,it is often accompanied by a large dark current due to the presence of abundant oxygen vacancy(VO)defects,which severely limits the possibility to detect weak signals and achieve versatile applications.In this work,the VO defects in a-Ga_(2)O_(3)thin films are successfully passivated by in-situ hydrogen doping during the magnetron sputtering process.As a result,the dark current of a-Ga_(2)O_(3)UV PD is remarkably suppressed to 5.17×10^(-11) A at a bias of 5 V.Importantly,the photocurrent of the corresponding device is still as high as 1.37×10^(-3)A,leading to a high photo-to-dark current ratio of 2.65×107 and the capability to detect the UV light with the intensity below 10 nW cm^(-2).Moreover,the H-doped a-Ga_(2)O_(3)thin films have also been deposited on polyethylene naphtholate substrates to construct flexible UV PDs,which exhibit no great degradation in bending states and fatigue tests.These results demonstrate that hydrogen doping can effectively improve the performance of a-Ga_(2)O_(3)UV PDs,further promoting its practical application in various areas.

关键词： Ga_(2)O_(3) hydrogen doping ultraviolet photodetector photo-to-dark current ratio neutron reflection

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Establishment of NaLuF_(4):15%Tb-based low dose X-PDT agent and its application on efficient antitumor therapy

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International Journal of Minerals,Metallurgy and Materials 2024年第3期31卷 599-610页

作者： Yi Tian Zhiguang Fu Xiaosheng Zhu Chunjing zhan Jinwei Hu Li Fan Chaojun Song Qian Yang Yu Wang mei Shi Department of Radiation Oncology Xijing HospitalThe Fourth Military Medical UniversityXi’an 710032China Department of Oncology Air Force Medical CenterPLAThe Fourth Military Medical UniversityBeijing 100142China Department of Tumor Radiotherapy Air Force Medical CenterPLAThe Fourth Military Medical UniversityBeijing 100142China Department of Gastroenterology Air Force Hospital of Southern Theater CommandGuangzhou 510062China Department of Pharmaceutical Chemistry and Analysis School of PharmacyThe Fourth Military Medical UniversityXi’an 710032China School of Life Sciences Northwestern Polytechnical UniversityXi’an 710072China Institue of Materia Medica School of PharmacyThe Fourth Military Medical UniversityXi’an 710032China

X-ray excited photodynamic therapy(X-PDT)is the bravo answer of photodynamic therapy(PDT)for deep-seated tumors,as it employs X-ray as the irradiation source to overcome the limitation of light penetration depth.However,high X-ray irradiation dose caused organ lesions and side effects became the major barrier to X-PDT application.To address this issue,this work employed a classic-al co-precipitation reaction to synthesize NaLuF_(4):15%Tb^(3+)(NLF)with an average particle size of(23.48±0.91)nm,which was then coupled with the photosensitizer merocyanine 540(MC540)to form the X-PDT system NLF-MC540 with high production of singlet oxygen.The system could induce antitumor efficacy to about 24%in relative low dose X-ray irradiation range(0.1-0.3 Gy).In vivo,when NLF-MC540 irradiated by 0.1 Gy X-ray,the tumor inhibition percentage reached 89.5%±5.7%.The therapeutic mechanism of low dose X-PDT was found.A significant increase of neutrophils in serum was found on the third day after X-PDT.By immunohistochemical staining of tumor sections,the Ly6G^(+),CD8^(+),and CD11c^(+)cells infiltrated in the tumor microenvironment were studied.Utilizing the bilat-eral tumor model,the NLF-MC540 with 0.1 Gy X-ray irradiation could inhibit both the primary tumor and the distant tumor growth.De-tected by enzyme linked immunosorbent assay(ELISA),two cytokines IFN-γand TNF-αin serum were upregulated 7 and 6 times than negative control,respectively.Detected by enzyme linked immune spot assay(ELISPOT),the number of immune cells attributable to the IFN-γand TNF-αlevels in the group of low dose X-PDT were 14 and 6 times greater than that in the negative control group,respectively.Thus,it conclude that low dose X-PDT system could successfully upregulate the levels of immune cells,stimulate the secretion of cy-tokines(especially IFN-γand TNF-α),activate antitumor immunity,and finally inhibit colon tumor growth.

关键词： X-ray excited photodynamic therapy singlet oxygen low dose X-Ray irradiation efficient antitumor therapy anti-tumor immunity

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Effect of blank quenching on shear spinning forming precision of 2219 aluminum alloy complex thin-walled components

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Chinese Journal of Aeronautics 2023年第4期36卷 538-555页

作者： Zhixin LI mei zhan Xiaoguang FAN Yunda DONG Luopeng XU School of Science Civil Aviation Flight University of ChinaGuanghan 618307China State Key Laboratory of Solidification Processing Shaanxi Key Laboratory of High-Performance Precision Forming

The quenching-spinning(Q-S)process,i.e.,shear spinning after blank quenching,has been increasingly utilized to form 2219 aluminum alloy complex thin-walled components.However,the changes in material property,shape and stress of the blanks after quenching will affect the spin-ning forming precision.In this study,the rules and mechanisms of these effects are investigated based on a combined finite element(FE)model including blank quenching and component spinning process.The results indicate that the increase of material strength and the existence of distortion of the quenched blank lead to a notable increase in the non-uniformity of the circumferential compres-sive stress in the spinning area and the increase of the flange swing height during spinning.These changes result in an increase in the wall thickness and component-mandrel gap of the components.The quenching residual stress has little effect on wall thickness and roundness but can noticeably reduce the component-mandrel gap.This is because that the existence of quenching residual stress of the blank can lead to the decrease of the maximum circumferential compressive stress of the workpiece in spinning and an obvious drop in the maximum compressive stress after reaching the stress peak.Quenching distortion is the main factor affecting the roundness.Moreover,the opti-mized installation way of the blank for spinning is obtained.

关键词： 2219 aluminum alloy Complex thin-walled com-ponents Finite element analysis Quenching distortion Residual stress Shear spinning

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Mesoscale deformation mechanisms in relation with slip and grain boundary sliding in TA15 titanium alloy during tensile deformation

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Journal of Materials Science & Technology 2022年第3期98卷 72-86页

作者： Yanxi Li Pengfei Gao Jingyue Yu Shuo Jin Shuqun Chen mei zhan State Key Laboratory of Solidification Processing Shaanxi Key Laboratory of High-Performance Precision Forming Technology and EquipmentSchool of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Key Laboratory of Advanced Functional Materials Education Ministry of ChinaSchool of Materials Science and EngineeringBeijing University of TechnologyBeijing 100124China

Revealing the mesoscale deformation mechanisms of titanium alloy with tri-modal microstructure is of great significance to improve its mechanical properties. In this work, the collective behavior and mechanisms of slip activities, slip transfer, and grain boundary sliding of tri-modal microstructure were investigated by the combination of quasi-in-situ tensile test, SEM, EBSD and quantitative slip trace analyses. It is found that the slip behavior presents different characteristics in the equiaxed α(α_(p)) and lamellar α(α_(l))grains. Under a low level of deformation, almost all the slip deformation is governed by single basal and prismatic slips for both of α_(p)and α_(l),despite small amount of -pyramidal slip exists in α_(l)grains. As deformation proceeds, -pyramidal and -pyramidal slip systems with high Schmid factors were activated in quantities. Specially, certain coarse prismatic slip bands were produced across both of single and colony α_(l)grains whose major axes tilting about 40 °–70 ° from the tensile axis. Slip transfer occurs at the boundaries of α_(p)/α_(p)and α_(l)/β under the condition that there exists perfect alignment between two slip systems and high Schmid factors of outgoing slip system. The slip transfer across α_(l)/β boundary can be divided into two types: straight slip transfer and deflect slip transfer with a deviation angle of 5 °–12 °, depending on the alignment of slip planes of two slip systems. The grain boundary sliding along boundaries of α_(l)/β and α_(p)/β was captured by covering micro-grid on tensile sample. It is found that the crystallographic orientation and the geometrical orientation related to loading axis play great roles in the occurrence of grain boundary sliding.

关键词： Titanium alloy Tri-modal microstructure Slip modes Slip transfer Grain boundary sliding

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Formability enhancement in hot spinning of titanium alloy thin-walled tube via prediction and control of ductile fracture

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Chinese Journal of Aeronautics 2022年第2期35卷 320-331页

作者： Pengfei GAO Chao YU Mingwang FU Lu XING mei zhan Jing GUO State Key Laboratory of Solidification Processing Shaanxi Key Laboratory of High-Performance Precision Forming Technology and EquipmentSchool of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Department of Mechanical Engineering The Hong Kong Polytechnic UniversityHung HornKowloonHong Kong 999077China Institute of Chemical Materials China Academy of Engineering PhysicsMianyang 621900China

The damage and fracture in hot spinning of titanium alloy is a very complex process under the combined effects of microstructure evolution and stress state.In this study,their dependences on processing parameters were investigated by an integrated FE model considering microstructure and damage evolution,and revealing the effects of microstructure and stress states on damage evolution.The results show that the inner surface of workpiece with the largest voids volume fraction is the place with the greatest potential of fracture.This is mainly attributed to the superposition effects of positive stress triaxiality and the smallest dynamic recrystallization(DRX)fraction andβphase fraction at the inner surface.The damage degree is decreased gradually with the increase of initial spinning temperature and roller fillet radius.Meanwhile,it is first decreased and then increased with the increases of spinning pass and roller feed rate,which can be explained based on the variations ofβphase fraction,DRX fraction,stress state and tensile plastic strain with processing parameters.In addition,the dominant influencing mechanisms were identified and discussed.Finally,the thickness reduction without defect in the hot spinning of TA15 alloy tube is greatly increased by proposing an optimal processing scheme.

关键词： Control of ductile fracture Dynamic recrystallization Forming limit Hot spinning Titanium alloy tube

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A Review on Ultrasonic-Assisted Forming:Mechanism,Model,and Process

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Chinese Journal of Mechanical Engineering 2021年第5期34卷 147-170页

作者： Guangda Shao Hongwei Li mei zhan Shaanxi Key Laboratory of Precision Forming Technology and Equipment School of Materials Science and Engineering Northwestern Polytechnical University Xi’an China

Compared with conventional forming processes,ultrasonic-assisted forming technology with a high frequency and small amplitude can significantly improve the forming quality of materials.Owing to the advantages of reduced forming force,improved surface quality,avoidance of forming defects,and strengthened surface structure,ultrasonic-assisted forming technology has been applied to increasingly advanced forming processes,such as incremental forming,spinning,and micro-forming.However,in the ultrasonic-assisted forming process,there are multiple ultrasonic mechanisms,such as the volume effect and surface effect.The explanation of the effect of ultrasonic vibration(UV)on plastic deformation remains controversial,hindering the development of related technologies.Recently,many researchers have proposed many new theories and technologies for ultrasonic-assisted forming.To summarize these developments,systematic discussions on mechanisms,theoretical models,and forming performances are provided in this review.On this basis,the limitations of the current study are discussed.In addition,an outlook for ultrasonic-assisted forming is proposed:efficient and stable UV systems,difficulty forming components with complex geometry,explanation of the in-depth mechanism,a systematic theoretical prediction model,and multi-field-coupling energy-assisted forming are considered to be hot spots in future studies.The present review enhances existing knowledge of ultrasonic-assisted forming,and facilitates a fast reference for related researchers.

关键词： Ultrasonic vibration Forming Mechanism Model Processing performance

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Integrated gut microbiota,plasma metabolomics and network pharmacology to reveal the anti-ischemic stroke effect of cooked rhubarb

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Traditional Medicine Research 2024年第9期9卷 1-13页

作者： Ting Li Lan-Fang Tan Lin Shen Jie-Hui Kuang Si-Kai zhan Bang Liu Jia-Le Cai Sheng-Wang Liang Ming-Hua Xian Shu-mei Wang School of Chinese Materia Medica Guangdong Pharmaceutical UniversityGuangzhou 510006China Key Laboratory of Digital Quality Evaluation of Chinese Materia Medica of State Administration of TCM School of Chinese Materia MedicaGuangdong Pharmaceutical UniversityGuangzhou 510006China Engineering&Technology Research Center for Chinese Materia Medica Quality of the Universities of Guangdong Province School of Chinese Materia MedicaGuangdong Pharmaceutical UniversityGuangzhou 510006China Guangxi Key Laboratory of Functional Phytochemicals Research and Utilization Guangxi Institute of BotanyChinese Academy of SciencesGuilin 541006China Traditional Chinese Medicine Resource Germplasm Bank Management Center Yunfu 527300China

Background:Cooked rhubarb(CR)is obtained by steaming raw rhubarb(Rheum palmatum L.,Rheum officinale Baill.,or Rheum tanguticum Maxim.ex Balf.)with millet wine.It is used as a traditional Chinese medicine for treating cerebral stroke,where patients often face severe constipation.This study explored the pharmacological effects and mechanisms of CR against ischemic stroke(IS)in rats.We used integrated analysis of gut microbiota,metabolomics,and network pharmacology.Methods:The compounds in CR were identified using LC-MS/MS.The impact of CR on rat middle cerebral artery occlusion/reperfusion(MCAO/R)-induced cerebral infarct size and brain tissue pathology was assessed through 2,3,5-triphenyl tetrazolium chloride and HE staining.Changes in hemorheology were measured by evaluating blood viscosity,and serum levels of pro-inflammatory cytokine were also determined.Gut microbiota composition was analyzed through 16S rRNA gene sequencing.Serum metabolites were examined using untargeted metabolomics and Spearman correlation analysis.The pseudo-germ-free test was used to determine whether tumour necrosis factor-α(TNF-α)and interleukin-1β(IL-1β)improvement in IS are dependent on gut microbiota.Results:In vivo studies showed CR enhances neurobehavioral function in MCAO/R rats and reduces cerebral infarction area.CR also ameliorates brain and intestinal barrier damage caused by stroke.It also decreased inflammation and oxidative stress in IS rats.Furthermore,CR promotes the growth of Akkermansia and Verrucomicrobia,aiding in intestinal barrier repair.Notably,CR primarily influences the primary bile acid biosynthesis pathway.The pseudo-germ-free experiment and network pharmacology confirmed TNF-αand IL-1βas potential targets.CR relies on gut microbiota for its anti-inflammatory effects to improve IS.Conclusion:Cooked rhubarb offers neuroprotective benefits by enhancing beneficial bacteria abundance and regulating bile acid metabolism.It emerges as a potential therapeutic agent for IS.

关键词： cooked rhubarb ischemic stroke gut microbiota metabolomics

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Dependence on forming parameters of an integral panel during the electromagnetic incremental forming process

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Chinese Journal of Aeronautics 2018年第7期31卷 1625-1634页

作者： Jinqiang TAN mei zhan Hongwei LI State Key Laboratory of Solidification Process School of Materials Science & Engineering Northwestern Polytechnical University

Nowadays, more and more attentions are paid to electromagnetic incremental forming（EMIF）, especially for a part with a large-scale size, e.g., an integral panel with stiffened ribs. In this work, the bending of a panel into a double-curvature profile via EMIF is carried out experimentally and evaluated by comparing the formed profile with the desired profile. During the process,discharges at four positions along different discharge paths are designed. The effects of forming parameters on the die-fittingness of the workpiece are discussed, for which two evaluation indices are used to judge forming results. The results show that a discharge voltage in an incremental mode is helpful to improve the fittingness and avoid the collision rebound against the die at the same time.Discharging at the diagonal positions with the ‘‘X＂ discharge path exhibits the minimal shape deviation and the best forming uniformity. On the contrary, discharging at the parallel positions with the ‘‘Z＂ discharge path obtains the worst forming quality. Overlap of the coil at different positions should be given during EMIF; however, a lower overlap rate of the coil helps improve the forming quality. The results obtained in this work are useful for forming integral panels with stiffened ribs via the EMIF process.

关键词： Electromagnetic incrementalforming （EMIF） Forming uniformity Integral panel Parameters Shape deviation

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Robust optimization of the billet for isothermal local loading transitional region of a Ti-alloy rib-web component based on dual-response surface method

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Frontiers of Mechanical Engineering 2018年第3期13卷 376-384页

作者： Ke WEI Xiaoguang FAN mei zhan Miao MENG State Key Laboratory of Solidification Processing School of Materials Science and Engineering Northwestern Polytechnical University Xi'an 710071 China

Billet optimization can greatly improve the forming quality of the transitional region in the isothermal local loading forming （ILLF） of large-scale Ti-alloy ribweb components. However, the final quality of the transitional region may be deteriorated by uncontrollable factors, such as the manufacturing tolerance of the preforming billet, fluctuation of the stroke length, and friction factor. Thus, a dual-response surface method （RSM）-based robust optimization of the billet was proposed to address the uncontrollable factors in transi- tional region of the ILLF. Given that the die underfilling and folding defect are two key factors that influence the forming quality of the transitional region, minimizing the mean and standard deviation of the die underfilling rate and avoiding folding defect were defined as the objective function and constraint condition in robust optimization. Then, the cross array design was constructed, a dual-RSM model was established for the mean and standard deviation of the die underfilling rate by considering the size parameters of the billet and uncontrollable factors. Subsequently, an optimum solution was derived to achieve the robust optimization of the billet. A case study on robust optimization was conducted. Good results were attained for improving the die filling and avoiding folding defect, suggesting that the robust optimization of the billet in the transitional region of the ILLF was efficient and reliable.

关键词： isothermal local loading forming rib-web component transitional region robust optimization dual response surface method

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Analysis of anisotropy mechanism in the mechanical property of titanium alloy tube formed through hot flow forming

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Journal of Materials Science & Technology 2021年第27期86卷 77-90页

作者： Zhenni Lei Pengfei Gao Xianxian Wang mei zhan Hongwei Li State Key Laboratory of Solidification Processing Shaanxi Key Laboratory of High-Performance Precision Forming Technology and EquipmentSchool of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an710072China College of Mechanical&Electrical Engineering Shaanxi University of Science&TechnologyXi’an710021China

Anisotropy of mechanical property is an important feature influencing the service performance of titanium(Ti)alloy tube component.In this work,it is found that the hot flow formed Ti alloy tube exhibits higher yield strength along circumferential direction(CD),and larger elongation along rolling direction(RD),presenting significant anisotropy.Subsequently,the quantitative characteristics and underlying mechanism of the property anisotropy were revealed by analyzing the slip,damage and fracture behavior under the combined effects of the spun{0002}basal texture and fibrous microstructure for different loading directions.The results showed that the prismatic slip in primaryαgrain is the dominant deformation mechanism for both loading directions at the yielding stage.The prismatic slip is harder under CD loading,which makes CD loading present higher yield strength than RD loading.Additionally,the yield anisotropy can be quantified through the inverse ratio of the averaged Schmid Factor of the activated prismatic slip under different loading directions.As for the plasticity anisotropy,the harder and slower slip development under CD loading causes that the CD loading presents larger external force and normal stress on slip plane,thus leading to more significant cleavage fracture than RD loading.Moreover,the micro-crack path under RD loading is more tortuous than CD loading because the fibrous microstructure is elongated along RD,which may suppress the macro fracture under RD loading.These results suggest that weakening the texture and fibrous morphology of microstructure is critical to reduce the differences in slip,damage and fracture behavior along different directions,alleviate the property anisotropy and optimize the service performance of Ti alloy tube formed by hot flow forming.

关键词： Titanium alloy tube Hot flow forming Mechanical property anisotropy Slip behavior Damage evolution

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