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Constructing two-scale network microstructure with nano-Ti5si3 for superhigh creep resistance

journal of Materials science & Technology 2019年第8期35卷 1532-1542页

作者： Y.jiao l.j.huang s.l.Wei h.x.Peng Q.An s.j.ang l.geng state Key laboratory of Advanced Welding and joining Harbin Institute of TechnologyHarbin 150001 China Center of Analysis and Measurement Harbin Institute of TechnologyHarbin 150001 China department of Materials science and Engineering Massachusetts Institute of TechnologyCambridge MA02139 USA Institute for Composites science Innovation (InCsI) School of Materials Science and EngineeringZhejiang UniversityHangzhou 310027 China

The improvement of mechanical properties must be achieved by designing and constructing more suitable microstructure,such as hierarchical *** order to significantly enhance the creep resistance of titanium matrix composites(TMCs),two-scale network microstructure was constructed including the first-scale network(h micro-TiB whisker(TiBw)reinforcement and the second-scale network(h nano-Ti5si3 reinforcement by powder metallurgy and in-situ *** results showed that the creep rate of the composite was remarkably reduced by an order of magnitude compared with the Ti6Al4V alloy at 550℃,600℃,650℃ under the stresses between 100 MPa and 350 ***,the rupture time of the composite was increased by 20 times,compared with that of the Ti6Al4 Valloy at 550℃/300 *** superior creep resistance could be attributed to the hierarchical *** micro-TiBw reinforcement in the first-scale network boundary contributed to creep resistance primarily by blocking grain boundary sliding,while the nano-Ti5si3 particle in the second-scale network boundary mainly by hindering phase boundary *** addition,the nano-Ti5si3 particle was dissolved,and precipitated with smaller size than the primary *** phenomenon was attributed to si element diffusion under high temperature and external stress,which could further continuously enhance the creep ***,the creep rate during steady-state stage was significantly decreased,which manifested superior creep resistance of the composite.

关键词： Titanium matrix composite Two-scale network microstructure Nano-Ti5si3 Creep Powder metallurgy

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A new scale for optimized cryogenic magnetocaloric effect in ErAl_2@Al_2O_3 nanocapsules

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journal of Materials science & Technology 2018年第5期34卷 848-854页

作者： F.Wei s.Ma l.Yang Y.Feng j.Z.wang A.hua x.g.Zhao d.Y.geng Z.d.Zhang shenyang National laboratory for Materials science Institute of Metal ResearchChinese Academy of Sciences

The Er Al2@Al2O3 nanocapsules with Er Al2core and Al2O3 shell were synthesized by modified arc-charge *** typical core-shell structure of the nanocapsules was confirmed by high resolution transmission electron microscopy and x-ray photoelectron *** electron microscopy analysis shows the irregular sphere of the nanocapules with an average diameter of 26 *** investigation revealed the Curie temperature of Er Al2@Al2O3 nanocapsules at 20 K and the typical superparamagnetic behavior between blocking temperature and Curie *** on the blocking temperature and average diameter,the magnetocrystalline anisotropy constant of Er Al2@Al2O3nanocapsules was estimated to illustrate the magnetic contribution to *** large-sMof 14.25 j/（kg K）was obtained under 50 k Oe at 5 K.A vital parameter β was introduced in the present work to scale the optimized magnetic characteristics and the optimized mechanism was discussed in detail according to classical superparamagnetic *** results demonstrate that the optimal-sMwill be obtained when the magnetic parameter β is close to the theoretical coefficient.

关键词： Nanocapsules Magnetocaloric effect superparamagnetic property Cryogenic refrigeration

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NUMERICAl sIMUlATION OF CAsTINg's MOld FIllINg PROCEss

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Acta Metallurgica sinica(English letters) 2005年第6期18卷 724-730页

作者： j.x. Zhou R.x. liu l.l. Chen d.M. liao h. s. Wei state Key lab of die and Mold Technology Huazhong University of Science and Technology Wuhan 430074 China

Numerical simulation of casting＇s mold filling process is the main and the most important aspect of the foundry CAE technology. But it is time-consuming; it may take dozens of hours or several days. While with the development of computer hardware, numerical simulation of casting＇ s mold filling process has made rapid progress. The simulation results, therefore, have become more and more practical. This study tries to find some clues of the computational time of mold filling process. Firstly, this paper introduces mathematic model and the basic route of numerical simulation of casting＇s mold filling process. Then the computational time of mold filling process has been carefully studied, and some new and useful results have been gained from the study of the computational time. Finally, this paper has given some real applications of numerical simulation of casting＇s mold filling process.

关键词： numerical simulation mold filling process casting

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Effects of chemical pressure on diluted magneticsemiconductor(Ba,K)(Zn,Mn)_2As_2

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Chinese Physics B 2019年第5期28卷 288-292页

作者： Y Peng s Yu g Q Zhao W M li j F Zhao l P Cao x C wang Q Q liu s.j.Zhang R Z Yu Z deng x.h.Zhu C Q jin College of Materials science & Engineering Sichuan University Beijing National laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences school of Physics University of Chinese Academy of Sciences Collaborative Innovation Center of Quantum Matter

Chemical pressure induced by iso-valent doping has been widely employed to tune physical properties of materials. In this work, we report effects of chemical pressure by substitution of sb or P into As on a recently discovered diluted magnetic semiconductor(Ba,K)(Zn,Mn)_2 As_2, which has the record of reliable Curie temperature of 230 K due to independent charge and spin doping. sb and P are substituted into As-site to produce negative and positive chemical pressures, respectively.x-ray diffraction results demonstrate the successful chemical solution of dopants. Magnetic properties of both K-underdoped and K-optimal-doped samples are effectively tuned by sb-and P-doping. The hall effect measurements do not show decrease in carrier concentrations upon sb-and P-doping. Impressively, magnetoresistance is significantly improved from7% to 27% by only 10% P-doping, successfully extending potential application of(Ba,K)(Zn,Mn)_2 As_2.

关键词： chemical pressure (Ba,K)(Zn,Mn)2As2 diluted magnetic semiconductor iso-valent doping

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Nanocarrier-mediated siRNA delivery:a new approach for the treatment of traumatic brain injury-related Alzheimer's disease

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Neural Regeneration Research 2025年第9期20卷 2538-2555页

作者： jie jin huajing Zhang Qianying lu linqiang Tian sanqiao yao Feng lai Yangfan liang Chuanchuan liu Yujia lu s.j.a Tian Yanmei Zhao Wenjie Ren Institute of disaster and Emergency Medicine Tianjin UniversityTianjinChina Key laboratory for disaster Medicine Technology TianjinChina henan Medical Key laboratory for Research of Trauma and Orthopedics The Third Affiliated Hospital of Xinxiang Medical UniversityXinxiangHenan ProvinceChina Clinical Medical Center of Tissue Engineering and Regeneration Xinxiang Medical UniversityXinxiangHenan ProvinceChina Institutes of health Central Plain Xinxiang Medical UniversityXinxiangHenan ProvinceChina school of Public health Xinxiang Medical UniversityXinxiangHenan ProvinceChina

Traumatic brain injury and Alzheimer's disease share pathological similarities,including neuronal loss,amyloid-βdeposition,tau hyperphosphorylation,blood-brain barrier dysfunction,neuroinflammation,and cognitive ***,traumatic brain injury can exacerbate Alzheimer's disease-like pathologies,potentially leading to the development of Alzheimer's *** offer a potential solution by facilitating the delive ry of small interfering RNAs across the blood-brain barrier for the targeted silencing of key pathological genes implicated in traumatic brain injury and Alzheimer's disease.U nlike traditional approaches to neuro regeneration,this is a molecula r-targeted strategy,thus avoiding non-specific drug *** review focuses on the use of nanocarrier systems for the efficient and precise delive ry of siRNAs,discussing the advantages,challenges,and future *** principle,siRNAs have the potential to target all genes and non-targetable protein s,holding significant promise for treating various *** the various therapeutic approaches currently available for neurological diseases,siRNA gene silencing can precisely"turn off"the expression of any gene at the genetic level,thus radically inhibiting.d.sease progression;however,a significant challenge lies in delivering siRNAs across the blood-brain *** have received increasing attention as an innovative drug.d.live ry tool fo r the treatment of brain *** are considered a potential therapeutic strategy with the advantages of being able to cross the blood-brain barrier,targeted drug.d.livery,enhanced drug stability,and multifunctional *** use of nanoparticles to deliver specific modified siRNAs to the injured brain is gradually being recognized as a feasible and effective *** this strategy is still in the preclinical exploration stage,it is expected to achieve clinical translation in the future,creating a new field of molecular tar

关键词： blood-brain barrier cognitive dysfunction exosomes gene silencing immunotherapy inorganic nanomaterials liposome nanoparticles neuroinflammation polymer nanoparticles stem cells

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Phased Array Feed Experiments and galactic hI Observations

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Research in Astronomy and Astrophysics 2023年第8期23卷 297-307页

作者： B.liu h.W.xi d.j.ding Z.W.wang s.h.Yu Y.Zhu l.Yu x.Zhang j.l.li l.j.liu Q.su Y.Wu C.j.jin B.Peng National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China Key laboratory of Radio Astronomy and Technology Chinese Academy of SciencesBeijing 100101China school of Astronomy and space science University of Chinese Academy of SciencesBeijing 100049China The 54th Research Institute of China Electronic Technology group Cooperation Shijiazhuang 050081China

The Phased Array Feed(PAF)is considered as one of the next generation receivers for radio telescopes,which can significantly enlarge the instantaneous Field-of-View of large aperture single dish radio telescopes and enable more fl.x.ble observing *** efforts on PAF development for radio telescopes have been made for more than two decades and have become more and more *** report the development of an ambient-temperature 19 element l-band PAF system and the experimental results including its far field beam pattern and system temperature measurement,which achieve the *** the aperture array beam-forming method,we demonstrate a wide-field galactic hI observations in the radio camera *** results indicate that this system might be applicable for strong galactic transient *** system could be directly equipped to large telescopes like the Five-hundred-meter Aperture spherical radio Telescope(FAsT)and FAsT array in the future.

关键词： instrumentation detectors-techniques imaging spectroscopy-line profiles

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Thin ceramic PZT dual-and multi-frequency pMUT arrays for photoacoustic imaging

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Microsystems & Nanoengineering 2022年第6期8卷 23-34页

作者： Qincheng Zheng haoran wang hao Yang huabei jiang Zhenfang Chen yao lu Philip x.-l.Feng huikai xie school of Integrated Circuits and Electronics Beijing Institute of Technology(BIT)100081 BeijingChina department of Electrical and Computer Engineering University of FloridaGainesvilleFL 32611USA department of Medical Engineering University of South FloridaTampaFL 33620USA MEMs Engineering and Materials Inc. SunnyvaleCA 94086USA BIT Chongqing Institute of Microelectronics and Microsystems 400030 ChongqingChina

Miniaturized ultrasonic transducer arrays with multiple frequencies are key components in endoscopic photoacoustic imaging(PAI)systems to achieve high spatial resolution and large imaging.d.pth for biomedical *** this article,we report on the development of ceramic thin-film PZT-based dual-and multi-frequency piezoelectric micromachined ultrasonic transducer(pMUT)arrays and the demonstration of their PAI *** chips sized 3.5mm in length or 10mm in diameter,square and ring-shaped pMUT arrays incorporating as many as 2520 pMUT elements and multiple frequencies ranging from 1 Mhz to 8 Mhz were developed for endoscopic PAI *** ceramic PZT with a thickness of 9μm was obtained by wafer bonding and chemical mechanical polishing(CMP)techniques and employed as the piezoelectric layer of the pMUT arrays,whose piezoelectric constant d_(31)was measured to be as high as 140 pm/*** from this high piezoelectric constant,the fabricated pMUT arrays exhibited high electromechanical coupling coefficients and large vibration *** addition to electrical,mechanical,and acoustic characterization,PAI experiments with pencil leads embedded into an agar phantom were conducted with the fabricated dual-and multi-frequency pMUT *** signals were successfully detected by pMUT elements with different frequencies and used to reconstruct single and fused photoacoustic images,which clearly demonstrated the advantages of using.d.al-and multi-frequency pMUT arrays to provide comprehensive photoacoustic images with high spatial resolution and large signal-to-noise ratio simultaneously.

关键词： ceramic piezoelectric dual

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Effect of Temperature on Material Transfer Behavior at different stages of Friction stir Welded 7075-T6 Aluminum Alloy

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journal of Materials science & Technology 2013年第10期29卷 955-960页

作者： s.d.ji Y.Y.jin Y.M.Yue s.s.gao Y.x.h.ang l.wang Faculty of Aerospace Engineering Shenyang Aerospace University state Key laboratory of Advanced Welding and joining Harbin Institute of Technology

In this work, the morphologies of weld of 7075-T6 aluminum alloy via friction stir welding （FsW） were analyzed by optical microscopy, the temperature field was attained by numerical simulation, and the effect of temperature on material transfer behavior in the thermal-mechanical affected zone （TMAZ） at different stages was mainly investigated. The FsW process consists of three stages. It is very interesting to find that the maximum transfer displacement of material appears at the final stage of welding process, then at the stable stage and at the initial stage, which results from the difference of peak temperatures at different stages. At any stage, the material in TMAZ near the surface of weld transfers downwards, the material in the middle of weld moves upwards and the material near the bottom of weld hardly moves. In any cross section of weld, the largest transfer displacement of material appears in the middle of weld. The increase of rotational velocity and the decrease of welding speed are both beneficial to the transfer displacement of material in the middle of weld.

关键词： Friction stir welding 7075-T6 aluminum alloy Thermal-mechanical affected zone Material transfer Numerical simulation

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Microstructure and mechanical properties of double-side friction stir welded 6082Al ultra-thick plates

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journal of Materials science & Technology 2020年第6期41卷 105-116页

作者： C.Yang j.F.Zhang g.N.Ma l.h.Wu x.M.Zhang g.Z.he P.xue d.R.Ni B.l.x.ao K.s.wang Z.Y.Ma shenyang National laboratory for Materials science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China school of Materials science and Engineering University of Science and Technology of ChinaShenyang 110016China CRRC Changchun Railway Vehicles Co. Ltd.Changchun 130062China school of Metallurgical Engineering Xi’an University of Architecture and TechnologyXi’an 710055China

In the present work,80 mm thick 6082Al alloy plates were successfully double-side welded by friction stir welding(FsW).The relationship between the microstructures and mechanical properties was built for the double-side FsW butt joint with more attention paid to the local characteristic *** was shown that a phenomenon of microstructural inhomogeneity existed in the nugget zone(NZ)through the thickness *** grain size presented an obvious gradient distribution from the top to the bottom for each single-pass weld,and the microhardness values decreased from both surfaces to the middle of the *** lowest hardness zone(lhZ)exhibited a"hyperbolical"-shaped distribution extending to the middle of the *** tensile properties were obtained in the three sliced specimens of the FsW joint,and the joint coefficient reached about 70%which achieved the same level as the conventional FsW Al alloy *** element modeling proved that the"hyperbolical"-shaped heat affected zone(hAZ)was beneficial to resisting the strain concentration in the middle layer specimen which helped to increase the tensile *** on the analysis of the hardness contour map,tensile property and microstructural evolution of the joints,an Isothermal softening layer(Isl)model was proposed and established,which may have a helpful guidance for the optimization on the FsW of ultra-thick Al alloy plates.

关键词： Ultra-thick aluminum alloy plates double-side friction stir welding Finite element model Microstructural inhomogeneity Mechanical properties

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NMR Evidence for Universal Pseudogap Behavior in Quasi-Two-dimensional Fese-Based superconductors

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Chinese Physics letters 2022年第12期39卷 71-76页

作者： B.l.Kang M.Z.shi d.Zhao s.j.li j.li l.x.Zheng.d.W.song l.P.Nie T.Wu x.h.Chen hefei National Research Center for Physical sciences at the Microscale University of Science and Technology of ChinaHefei 230026China Key laboratory of strongly coupled Quantum Matter Physics Department of PhysicsUniversity of Science and Technology of ChinaHefei 230026China CAs Center for Excellence in superconducting Electronics(CENsE) Shanghai 200050China 4Collaborative Innovation Center of Advanced Microstructures Nanjing UniversityNanjing 210093China hefei National laboratory University of Science and Technology of ChinaHefei 230088China

Recently,by intercalating organic ions into bulk Fese superconductors,two kinds of layered Fese-based superconductors[(TBA)xFese and(CTA)xFese]with superconducting transition temperatures(Tc)above 40 K have been *** to the large interlayer distance(~15A),these new layered superconductors have a large resistivity anisotropy analogous to bismuth-based cuprate ***,remarkable pseudogap behavior well above Tcis revealed by nuclear magnetic resonance(NMR)measurements on77se nuclei,suggesting a preformed pairing scenario similar to that of ***,we report another new kind of organic-ion-intercalated Fese superconductor,(PY)xFese,with a reduced interlayer distance(~10A)compared to(TBA)xFese and(CTA)*** performing77se NMR and transport measurements,we observe a similar pseudogap behavior well above Tcof~40 K and a large resistivity anisotropy of~10~4 in(PY)*** these facts strongly support a universal pseudogap behavior in these layered Fese-based superconductors with quasi-two-dimensional electronic structures.

关键词： NMR superconductors layered

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