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Advances of machining techniques for gradient structures in multi-principal-element alloys

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Rare Metals 2022年第12期41卷 4015-4026页

作者： Bo Li Chun-Ming Niu tian-long zhang Gong-Yu Chen Gang zhang Dong Wang Xiao-Ye Zhou Jia-Ming Zhu School of Civil Engineering Shandong UniversityJinan 250061China School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China Department of Materials Science and Engineering College of Science and EngineeringHong Kong Institute for Advanced StudyCity University of Hong KongHong Kong 999077China School of Physics and Optoelectronics Technology Baoji University of Arts and SciencesBaoji 721016China Center of Microstructure Science Frontier Institute of Science and TechnologyXi'an Jiaotong UniversityXi’an 710049China Guangdong Province Key Laboratory of Durability for Marine Civil Engineering School of Civil and Transportation EngineeringShenzhen UniversityShenzhen 518060China

Multi-principal-element alloys(MPEAs)are attracting increasing attentions because of their high strength and ductility,high fracture toughness,excellent corrosion resistance,outstanding thermal-softening resistance and high oxidation ***,gradient structures(GSs)have been shown to be effective in alleviating the strength-ductility trade-off although strength and ductility are mutually exclusive properties for metals,which provides an opportunity for developing highperformance ***,we summarized four processing methods for creating GSs in MPEAs,including rotationally accelerated shot peening(RASP),ultra-precision machining technology(UPMT),cyclic dynamic torsion(CDT),and ultrasonic surface rolling processing(USRP).Principles,advantages,disadvantages,and typical applications of these methods are discussed in this work.

关键词： Gradient structures(GSs) Multi-principalelement alloys(MPEAs) Strength-ductility trade-off Advanced processing technology

Learning the imaging mechanism directly from optical microscopy observations

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Photonics Research 2024年第1期12卷 7-26页

作者： ZE-HAO WANG long-KUN SHAN TONG-tian WENG tian-long CHEN XIANG-DONG CHEN zhang-YANG WANG GUANG-CAN GUO FANG-WEN SUN CAS Key Laboratory of Quantum Information University of Science and Technology of ChinaHefei 230026China CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of ChinaHefei 230026China University of Texas at Austin AustinTexas 78705USA Hefei National Laboratory University of Science and Technology of ChinaHefei 230088China

The optical microscopy image plays an important role in scientific research through the direct visualization of the nanoworld,where the imaging mechanism is described as the convolution of the point spread function(PSF)and *** on a priori knowledge of the PSF or equivalent PSF,it is possible to achieve more precise exploration of the ***,it is an outstanding challenge to directly extract the PSF from microscopy ***,with the help of self-supervised learning,we propose a physics-informed masked autoencoder(PiMAE)that enables a learnable estimation of the PSF and emitters directly from the raw microscopy *** demonstrate our method in synthetic data and real-world experiments with significant accuracy and noise *** outperforms DeepSTORM and the Richardson–Lucy algorithm in synthetic data tasks with an average improvement of 19.6%and 50.7%(35 tasks),respectively,as measured by the normalized root mean square error(NRMSE)*** is achieved without prior knowledge of the PSF,in contrast to the supervised approach used by DeepSTORM and the known PSF assumption in the Richardson–Lucy *** method,PiMAE,provides a feasible scheme for achieving the hidden imaging mechanism in optical microscopy and has the potential to learn hidden mechanisms in many more systems.

关键词： optical emitter mechanism

Human umbilical cord mesenchymal stem cells derivedexosomes on VEGF-A in hypoxic-induced mice retinal astrocytes and mice model of retinopathy of prematurity

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International Journal of Ophthalmology(English edition) 2024年第7期17卷 1238-1247页

作者： Xiao-tian zhang Bo-Wen Zhao Yuan-long zhang Song Chen tianjin Eye Hospital Tianjin 300020China tianjin Key Lab of Ophthalmology and Visual Science Tianjin 300020China

AIM:To observe the effect of human umbilical cord mesenchymal stem cells(hUCMSCs)secretions on the relevant factors in mouse retinal astrocytes,and to investigate the effect of hUCMSCs on the expression of vascular endothelial growth factor-A(VEGF-A)and to observe the therapeutic effect on the mouse model of retinopathy of prematurity(ROP).METHODS:Cultured hUCMSCs and extracted exosomes from them and then retinal astrocytes were divided into control group and hypoxia *** assay,flow cytometry,reverse transcription-polymerase chain reaction(RT-PCR)and Western blot were used to detect related *** mechanisms by which hUCMSCs exosomes affect VEGF-A expression in hypoxia-induced mouse retinal astrocytes were *** last,the efficacy of exosomes of UCMSCs in a mouse ROP model was ***6 was used to comprehensively process data ***:The secretion was successfully extracted from the culture supernatant of hUCMSCs by gradient *** oxygen species(ROS)and hypoxia inducible factor-1α(HIF-1α)of mice retinal astrocytes under different hypoxia time and the expression level of VEGF-A protein and VEGF-A mRNA increased,and the ROP cell model was established after 6h of *** secretions of medium and high concentrations of hUCMSCs can reduce ROS and HIF-1α,the expression levels of VEGF-A protein and VEGF-A mRNA are statistically significant and concentration *** with the ROP cell model group,the expression of phosphatidylinositol 3-kinase(PI3K)/protein kinase B(AKT)/mammalian target of rapamycin(mTOR)signal pathway related factors in the hUCMSCs exocrine group is significantly *** intravitreal injection of the secretions of medium and high concentrations of hUCMSCs can reduce VEGF-A and HIF-1αin ROP model *** staining shows that the number of retinal neovascularization in ROP mice decreases with the increase of the dose of hUCMSCs ***:In a hypoxia induced

关键词： human umbilical cord mesenchymal stem cells retinal astrocytes retinopathy of prematurity vascular endothelial growth factor hypoxia inducible factor

Insights into in-situ imbibition behavior of fracturing fluid in propped shale fractures based on nuclear magnetic resonance:A case study from longmaxi Formation shale,Sichuan Basin,China

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Petroleum Science 2024年第1期21卷 410-429页

作者： Jing-Jing Guo Kai-Xiang Di Lie-Hui zhang Yu-long Zhao Hui-Ying Tang Rui-Han zhang Ye tian National Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu610500SichuanChina

Shale gas is an important component of unconventional oil and gas *** the imbibition behavior is helpful to optimize flowback parameters and enhance gas *** imbibition studies have focused on shale matrix,and the pressure conditions discussed were mostly *** initial imbibition behavior begins from propped fractures to matrix,but there are few studies working on explaining the imbibition behavior in propped fractures or the phenomenon of many shale wells exhibit higher productivity after a“soaking”***,propped fracture samples were designed for imbibition and migration *** order to accurately study the mechanism and main influencing factors of fracturing fluid imbibition and migration in propped and unpropped shale fractures under high temperature and high pressure,a series of experiments based on nuclear magnetic resonance(NMR)were carried *** showed that NMR T_(2) spectra of all samples exhibited a bimodal *** final imbibition volume of fracturing fluid was positively related to pressure and fracture *** imbibition effect of fracturing fluid was more evident in matrix pores under high *** the migration during soaking stage,the fracturing fluid gradually migrated from large pores to small pores and gradually displaced the shale gas from the matrix,thus allowing the water blocking in propped fractures to self-unlock to some *** permeability decreased in the imbibition stage,while it recovered in the migration stage to some extent.

关键词： Forced imbibition Migration Soaking NMR T_(2)spectra Propped fracture Permeability recovery

Robust adaptive radar beamforming based on iterative training sample selection using kurtosis of generalized inner product statistics

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Journal of Systems Engineering and Electronics 2024年第1期35卷 24-30页

作者： tian Jing zhang Wei School of Information and Electronics Beijing Institute of TechnologyBeijing 100081China National Key Laboratory of Electromagnetic Space Security Chengdu 610036China

In engineering application,there is only one adaptive weights estimated by most of traditional early warning radars for adaptive interference suppression in a pulse reputation interval(PRI).Therefore,if the training samples used to calculate the weight vector does not contain the jamming,then the jamming cannot be removed by adaptive spatial *** the weight vector is constantly updated in the range dimension,the training data may contain target echo signals,resulting in signal cancellation *** cope with the situation that the training samples are contaminated by target signal,an iterative training sample selection method based on non-homogeneous detector(NHD)is proposed in this paper for updating the weight vector in entire range *** principle is presented,and the validity is proven by simulation results.

关键词： adaptive radar beamforming training sample selection non-homogeneous detector electronic jamming jamming suppression

Efficacy of Daoyin combined with lower limb robot as a comprehensive rehabilitation intervention for stroke patients: a randomized controlled trial

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Journal of Traditional Chinese Medicine 2024年第3期44卷 530-536页

作者： tian Haolin YANG Yuanbin zhang Hu ZHAO Wenjing ZHOU Jing tian Jingfeng HE long LI Xuechao SHEN Qinxuan SHUAI Mei Department of First Rehabilitation Wangjing Hospital of China Academy of Chinese Medical Sciences Department of Rehabilitation Shunyi HospitalBeijing Traditional Chinese Medicine Hospital School of Biological Science and Medical Engineering Beihang University

OBJECTIVE: To assess the effectiveness of a comprehensive rehabilitation approach combining Traditional Chinese Medicine Daoyin with lower limb robotics during the recovery phase of stroke ***: Stroke patients meeting the specified criteria were randomly assigned to one of four groups using a random number table: Control group, Daoyin group, lower limb robot group(LLR group), and Daoyin and lower limb robot group(DLLR group). Each group received distinct treatments based on conventional rehabilitation *** treatment duration spanned two weeks with two days of rest per week. Pre-and post-intervention assessments included various scales: Fugl-Meyer Assessment(FMA),Berg balance scale(BBS), Barthel index(BI), Fatigue Scale-14(FS-14), Pittsburgh sleep quality index(PSQI),Hamilton Anxiety Scale(HAMA), and Hamilton Depression Scale(HAMD).RESULTS: Statistically significant differences were observed in the lower limb function measured by FAM between the Control group(15 ± 5) and the DLLR group(18 ± 5)(P = 0.049). In the Barthel index, a statistically significant difference was noted between the Control group(54 ± 18) and the DLLR group(64 ± 11)(P = 0.041).Additionally, significant differences were found in the Berg balance scale between the Control group(21 ± 10)and the DLLR group(27 ± 8)(P = 0.024), as well as between the Control group(21 ± 10) and the LLR group(26 ± 10)(P = 0.048).CONCLUSION: The findings of this study suggest that the combined use of Daoyin and robotics not only enhances motor function in stroke patients but also has a positive impact on fatigue, sleep quality, and mood. This approach may offer a more effective rehabilitation strategy for stroke patients.

关键词： Daoyin lower limb robot randomized controlled trial rehabilitation stroke

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Fabrication of Al-Coated Mg-Li Alloy Sheet and Investigation of Its Properties

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Acta Metallurgica Sinica(English Letters) 2019年第2期32卷 169-177页

作者： tian-long zhang Toko Tokunaga Munekazu Ohno Mi-Lin zhang Kiyotaka Matsuura Graduate School of Engineering Hokkaido University Faculty of Engineering Hokkaido University College of Materials Science and Chemical Engineering Harbin Engineering University

An Al-coated Mg-8 mass% Li alloy rectangular bar was fabricated by hot extrusion, and then, it was hot-rolled into a thin sheet. The Al coating was uniform in thickness and had good bonding with the substrate during all the processing. This Alcoated Mg–Li alloy exhibited a good corrosion resistance in a 0.5 mass% HCl aqueous solution. No intermetallic compound was observed at the Al/Mg–Li interface after the extrusion and the rolling. The Al-coated Mg–Li alloy sheet exhibited an elongation to fracture of 35% at room temperature at a strain rate of 0.001 s(-1)without any debonding between the coating and the substrate. When tensile tested at 573 K at 0.001 s(-1)in the air, the Al coating remained undamaged even until an elongation of about 150%. Further elongation generated cracks on the coating and the specimen fractured at an elongation of about 200%. In an Ar atmosphere, the specimen exhibited a fracture elongation of over 400% under the same conditions at 573 K at 0.001 s(-1), although a large number of cracks generated on the Al coating.

关键词： Mg–Li alloy Composite material Coating Mechanical properties Superplasticity

Research on the slagging characteristics of blended coals in a pilot-scale furnace

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2015年第3期16卷 204-216页

作者： Hao ZHOU Le-tian LI Hai-long zhang Bin ZHOU Institute for Thermal Power Engineering Zhejiang University Hangzhou 310027 China

题目：中试台架上混煤结渣特性实验研究　　目的：混煤掺烧方式广泛应用于电站的实际生产中，但实际生产中出现了比源煤更为严重的结渣情况。为了研究混煤结渣特性，本文在中试台架上进行混煤结渣实验。　　创新点：在实验过程中采用 ... 详细信息

题目：中试台架上混煤结渣特性实验研究　　目的：混煤掺烧方式广泛应用于电站的实际生产中，但实际生产中出现了比源煤更为严重的结渣情况。为了研究混煤结渣特性，本文在中试台架上进行混煤结渣实验。　　创新点：在实验过程中采用 CCD 相机全程监控灰渣生长情况，通过对图片进行图像处理，可以获取灰渣的动态生长情况，更为详细地了解结渣特性。　　方法：1.在中试台架上燃烧不同比例配制的大同煤和陕煤的混煤，插入结渣探针和 CCD 探针进行结渣实验；2.对煤灰进行X射线荧光(XRF)分析获取氧化物含量；3.对灰渣横截面进行扫描电子显微术-能量色散X射线分析(SEM-EDX)，取不同层的粉末进行X射线衍射(XRD)分析。　　结论：1.混煤结渣厚度随着陕煤比例的增加而增加；2.各工况下结渣达到稳态所需时间随着陕煤比例增加而增加；3.灰渣截面都出现了明显的分层情况，主要元素在飞灰和灰渣之间有明显的选择性沉积。

关键词：混煤灰沉积结渣 CCD相机矿物学

Experimental Study on Wire Melting Control Ability of Twin-Body Plasma Arc

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 184-194页

作者： Ruiying zhang Fan Jiang long Xue School of Mechanical Engineering Beijing Institute of Petrochemical TechnologyBeijing 102617China Beijing Academy of Safety Engineering and Technology Beijing 102617China College of Mechanical and Energy Engineering Beijing University of TechnologyBeijing 100124China

The twin-body plasma arc has the decoupling control ability of heat transfer and mass transfer,which is beneficial to shape and property control in wire arc additive *** this paper,with the wire feeding speed as a characteristic quantity,the wire melting control ability of twin-body plasma arc was studied by adjusting the current separation ratio(under the condition of a constant total current),the wire current/main current and the position of the wire in the arc axial *** results showed that under the premise that the total current remains unchanged(100 A),as the current separation ratio increased,the middle and minimum melting amounts increased approximately synchronously under the effect of anode effect power,the first melting mass range remained constant;the maximum melting amount increased twice as fast as the middle melting amount under the effect of the wire feeding speed,and the second melting mass range was *** the wire current increased,the anode effect power and the plasma arc power were both factors causing the increase in the wire melting amount;however,when the main current increased,the plasma arc power was the only factor causing the increase in the wire melting *** average wire melting increment caused by the anode effect power was approximately 2.7 times that caused by the plasma arc *** minimum melting amount was not affected by the wire-torch distance under any current separation ratio *** the current separation ratio increased and reached a threshold,the middle melting amount remained constant with increasing wire-torch *** the current separation ratio continued to increase and reached the next threshold,the maximum melting amount remained constant with the increasing wire-torch *** effect of the wire-torch distance on the wire melting amount reduced with the increase in the current separation *** this study,the decoupling mechanism and ability of this innovative

关键词： Twin-body plasma arc Melting control ability Melting amount Current separation ratio