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Effects of aluminum co-doping on photoluminescence properties of Ce^(3+)-doped SiO_2 glasses

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Journal of Rare Earths 2010年第S1期28卷 206-210页

作者： LF KOAO h.C.SWART F.b.DEJENE Department of Physics University of the Free State(Qwaqwa Campus)Private Bag X13Phuthaditjhaba9866South Africa Department of Physics University of the Free StateP.O.Box 339Bloemfontein9300South Africa

SiO2 glasses co-doped with Al3+ ions were prepared by a sol-gel method by holding 0.5% of Ce3+ ions constant and varying the Al3+ ions *** stability,the structural,chemical and the optical properties of the samples were studied by using differential scanning calorimetric(DSC),thermo gravimetric analysis(TGA),X-ray diffraction(XRD),scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),UV-vis spectroscopy and photoluminescence spectroscopy(PL).The DSC and TGA of samples depicted that the presence of dopant and co-dopant decreased the endothermic peak temperature and the yield *** images showed that the particles were in the nano-range and spherical in *** XRD showed that all the samples were *** UV absorption measurements indicated that the presence of Al3+ ions significantly reduced the SiO2 absorption band,increased the absorbance intensity of SiO2 and decreased the transmittance as compared to the presence of the Ce3+ ions *** photoluminescence results displayed an optimum increase in luminescence intensity when the ratio of Al:Ce was 10:1 and further increase in aluminum content quenched the luminous intensity.

关键词： SiO2:Ce Al when sol-gel molar ration nano-size luminescence enhancement rare earths

blockade of Rho-associated kinase prevents inhibition of axon regeneration of peripheral nerves induced by anti-ganglioside antibodies

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Neural Regeneration Research 2024年第4期19卷 895-899页

作者： Andrés berardo Cristian R.bacaglio bárbara b.báez Rubén Sambuelli Kazim A.Sheikh Pablo h.h.Lopez Laboratorio de Neurobiología Instituto de Investigación Médica Mercedes y Martin Ferreyra(INIMEC)-Consejo Nacional de Investigaciones Cientificas y Técnicas(CONICET)Universidad Nacional de Córdoba Departamento de Química biológica-Centro de Investigaciones en Química biológica de Córdoba(CIQUIbIC)-Consejo Nacional de Investigaciones Cientificas y Técnicas(CONICET) Facultad de Cs.QuímicasUniversidad Nacional de Córdoba Servicio de Anatomía Patológica Clínica Universitaria Reina FabiolaUniversidad Católica de Córdoba Department of Neurology University of Texas Medical School at Houston

Anti-ganglioside antibodies are associated with delayed/poor clinical recovery in Guillain-barrèsyndrome,mostly related to halted axon ***-linking of cell surface gangliosides by anti-ganglioside antibodies triggers inhibition of nerve repair in in vitro and in vivo paradigms of axon *** effects involve the activation of the small GTPase Rho A/ROCK signaling pathways,which negatively modulate growth cone cytoskeleton,similarly to well stablished inhibitors of axon regeneration described so *** aim of this work was to perform a proof of concept study to demonstrate the effectiveness of Y-27632,a selective pharmacological inhibitor of ROCK,in a mouse model of axon regeneration of peripheral nerves,where the passive immunization with a monoclonal antibody targeting gangliosides GD1a and GT1b was previously reported to exert a potent inhibitory effect on regeneration of both myelinated and unmyelinated *** results demonstrate a differential sensitivity of myelinated and unmyelinated axons to the pro-regenerative effect of *** with a total dosage of 9 mg/kg of Y-27632 resulted in a complete prevention of anti-GD1a/GT1b monoclonal antibody-mediated inhibition of axon regeneration of unmyelinated fibers to skin and the functional recovery of mechanical cutaneous *** contrast,the same dose showed toxic effects on the regeneration of myelinated ***,scale down of the dosage of Y-27632 to 5 mg/kg resulted in a significant although not complete recovery of regenerated myelinated axons exposed to anti-GD1a/GT1b monoclonal antibody in the absence of toxicity in animals exposed to only ***,these findings confirm the in vivo participation of Rho A/ROCK signaling pathways in the molecular mechanisms associated with the inhibition of axon regeneration induced by anti-GD1a/GT1b monoclonal *** findings open the possibility of therapeutic pharmacological intervention targeting Rho A/R

关键词： anti-ganglioside antibodies anti-glycan antibodies axon regeneration ganglioside Guillain-barrésyndrome nerve repair ROCK Y-27632

Review of deployment technology for tethered satellite systems

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Acta Mechanica Sinica 2018年第4期34卷 754-768页

作者： b.S.Yu h.Wen D.P.Jin State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and Astronautics

Tethered satellite systems（TSSs） have attracted significant attention due to their potential and valuable applications for scientific research. With the development of various launched on-orbit missions, the deployment of tethers is considered a crucial technology for operation of a TSS. both past orbiting experiments and numerical results have shown that oscillations of the deployed tether due to the Coriolis force and environmental perturbations are inevitable and that the impact between the space tether and end-body at the end of the deployment process leads to complicated nonlinear phenomena. hence, a set of suitable control methods plays a fundamental role in tether deployment. This review article summarizes previous work on aspects of the dynamics, control, and ground-based experiments of tether deployment. The relevant basic principles, analytical expressions, simulation cases, and experimental results are presented as well.

关键词： Tethered satellite Deployment Dynamics Control Experiment

Antimonene-based saturable absorber for a soliton mode-locked and Q-switched fiber laser in the 2 μm wavelength region

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Chinese Physics b 2023年第6期32卷 259-269页

作者： h Ahmad b Nizamani M Z Samion N Yusoff M F Ismail Photonics Research Centre Universiti Malaya50603 Kuala LumpurMalaysia Physics Department Faculty of ScienceUniversiti Malaya50603 Kuala LumpurMalaysia Distinguished Visiting Professor Universiti Kuala Lumpur British Malaysian Institute(UniKL BMI)Batu 8Jln Sungai Pusu53100SelangorMalaysia

We demonstrate antimonene as a saturable absorber(SA) to generate an ultrafast mode-locked and Q-switched laser in the 2 μm wavelength region. The two antimonene-based SAs were prepared and inserted separately in a thulium–holmiumdoped fiber laser to produce the pulsed laser. Antimonene was coated onto a tapered fiber to generate soliton mode-locked pulses and used in thin-film form for the generation of Q-switched pulses. The mode-locking was stable within a pump power of 267 m W–511 m W, and the laser operated at a central wavelength of 1897.4 nm. The mode-locked laser had a pulse width of 1.3 ps and a repetition rate of 12.6 Mhz, with a signal-to-noise ratio of 64 d b. Q-switched laser operation was stable at a wavelength of 1890.1 nm within a pump power of 312 m W–381 m W. With the increase in pump power from 312 m W to 381 m W, the repetition rate increased to a maximum of 56.63 k hz and the pulse width decreased to a minimum value of 2.85 μs. Wide-range tunability of the Q-switched laser was also realized within the wavelength range of1882 nm–1936 nm.

关键词： mode-locking Q-switched fiber laser optical saturable absorber

Nanophase Decomposition of a Zn-Al based Alloy Zn_(68)Al_(10)Cu_(22)

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Journal of Materials Science & Technology 2004年第6期20卷 687-690页

作者： Y.h.Zhu W.b.Lee S.To Advanced Materials Research Center Department of Industrial and Systems Engineering The Hong Kong Polytechnic University Hong Kong ChinaAdvanced Materials Research Center Department of Industrial and Systems Engineering The Hong Kong Polytechnic University Hong Kong ChinaAdvanced Materials Research Center Department of Industrial and Systems Engineering The Hong Kong Polytechnic University Hong Kong China

The nanostructural evolution and phase transformation of the films of a Zn-Al based alloy (Zn68Al10Cu22 in wt pct) have been studied by using X-ray diffraction and scanning electron microscopy. Nanostructural thin films of the Zn-AI based alloy were produced by using an electron beam deposition technique. It was found that a nanocrystalline phase η'n had a strong preferred crystal orientation at (0002) crystal planes in the as-deposited films. During ageing at 220℃, the decomposition of nanophase η'n started with clustering to form Z-zones, and transitionai phase, which was accompanied by an eutectoid decomposition of the η'n phase: η'n β'eut T'. Decomposition, such as clustering and the formation of the Z-zones, and the transitionai phase etc. were observed in the nanophase β'eut. The formation and the decomposition of the transitionai phase of micrometers in size were involved in the decomposition of the main nanophase η'n. The mechanism of the Z-zones formation and the stability of nanophases were discussed.

关键词： Ageing Nanostructure Nanophase stability Zn-Al based alloy film

Microstructures and Mechanical Properties of Al/Mg Alloy Multilayered Composites Produced by Accumulative Roll bonding

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Journal of Materials Science & Technology 2011年第1期27卷 15-21页

作者： h.S. Liu b. Zhang G.P. Zhang Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China Key Laboratory for Anisotropy and Texture of Materials of Ministry of Education School of Materials & Metallurgy Northeastern University Shenyang 110004 China

Al/Mg alloy multilayered composites were produced successfully at the lower temperature（280 C） by accumulative roll bonding（ARb） processing *** microstructures of Al and Mg alloy layers were characterized by scanning electron microscopy and transmission electron *** hardness and three-point bending tests were conducted to investigate mechanical properties of the *** is found that Vickers hardness,bending strength and stiffness modulus of the Al/Mg alloy multilayered composite increase with increasing the ARb *** and crack propagation along the interface are the two main failure modes of the multilayered composite subjected to bending *** and fracture mechanisms of the composite are analyzed.

关键词： Accumulative roll bonding(ARb) Al/Mg alloy multilayered composite Ultra-fine grains hardness bending properties

Electronic structure and magnetic properties of rare-earth perovskite gallates from first principles

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Chinese Physics b 2017年第1期26卷 375-385页

作者： A Dahani h Alamri b Merabet A Zaoui S Kacimi A boukortt M bejar Laboratoire de Physique Computationnelle des Materiaux Universite Dfillali Liabes de Sidi Bel-Abbes Sidi Bel-Abbes 22000 Algeria Universite Moulay Tahar Faculte de Technologie Saida 20000 Algeria Umm AI-Qura University Physics Department-University College Makkah Saudi Arabia Universite Mustapha Stambouli Faculte de Technologie Mascara 29000 Algeria Elaboration Characterization Physico-Mechanics of Materials and Metallurgical Laboratory ECP3M Faculty of Sciences and Technology Abdelhamid Ibn Badis University of Mostaganem Mostaganem 27000 Algeria Laboratoire de Physique Appliquee Faculte des Sciences Universite de Sfax Sfax 3000 Tunisia

The density functional calculation is performed for centrosymmetric（La–Pm） GaO3 rare earth gallates, using a full potential linear augmented plane wave method with the LSDA and LSDA＋U exchange correlation to treat highly correlated electrons due to the very localized 4f orbitals of rare earth elements, and explore the influence of U = 0.478 Ry on the magnetic phase stability and the densities of states. LSDA＋U calculation shows that the ferromagnetic（FM） state of RGaO3 is energetically more favorable than the anti-ferromagnetic（AFM） one, except for LaGaO3 where the NM state is the lowest in energy. The energy band gaps of RGaO3 are found to be in the range of 3.8–4.0 eV, indicating the semiconductor character with a large gap.

关键词： DFT+U+SO strongly correlated electron systems magnetism rare earth gallates perovskites

Injection molding of micro-porous titanium alloy with space holder technique

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Rare Metals 2011年第6期30卷 565-571页

作者： Gülsah Engin bülent Aydemir h.zkan Gülsoy Marmara University Institute Graduate Studies Pure and Applied Sciences TUbITAK National Metrology Institute Marmara University Technical Education FacultyMaterials Department Tubitak-MRC Materials Technologies Research Institute

The powder space holder （PSh） and powder injection molding （PIM） methods have an industrial competitive advantage because they are capable of the net-shape production of micro-sized porous parts. In this study, micro-porous Ti6Al4V alloy （Ti64） parts were produced by the PSh-PIM process. Ti64 alloy powder and spherical polymethylrnethacrylate （PMMA） particles were used as a space holder material. After molding, binder debinding was performed by thermal method under inert gas. Debinded samples were sintered at 1250℃ for 60min in a vacuum （10-4 Pa）. Metallographic studies were conducted to determine densification and the corresponding microstructural changes. The surface of sintered samples was examined by SEM. The compressive stress and elastic modulus of the rificro-porous Ti64 samples were determined. The effects of fraction of PMMA on the properties of sintered micro-porous Ti64 alloy samples were investigated. It was shown that the fraction of PMMA could be controlled to affect the properties of the Ti alloy.

关键词： powder injection molding titanium powder porous metal sintering

Corrosion protection of NiNb metallic glass coatings for 316SS by magnetron sputtering

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Journal of Materials Science & Technology 2021年第20期79卷 88-98页

作者： L.Jiang Z.Q.Chen h.b.Lu h.b.Ke Y.Yuan Y.M.Dong X.K.Meng School of Chemistry and Life Sciences Suzhou University of Science and TechnologySuzhou 215009China Institute of Materials Engineering National Laboratory of Solid State MicrostructuresCollege of Engineering and Applied SciencesNanjing UniversityNanjing 210009China Songshan Lake Materials Laboratory Dongguan 523808China Institute of Physics Chinese Academy of SciencesBeijing 100190China Institute of Materials Engineering Nanjing UniversityNantong 226019China College of Chemistry and Chemical Engineering Nantong UniversityNantong 226019China

Metallic glasses(MGs)appear as promising anti-corrosion coating materials due to their microstructural and physicochemical ***,we proposed magnetron sputtered NiNb thin film MG coatings(MGCs)with different structures and compositions for corrosion protection of 316 stainless steel in an aggressive saline *** properties of monolayered Ni_(50)Nb_(50) and Ni_(60)Nb_(40),as well as the multilayered Ni_(50)Nb_(50)/Ni_(60)Nb_(40)(at.%)MGCs,were characterized in terms of morphology and microstructural properties,as well as the anticorrosion *** the NiNb MGCs presented compact structure and the monolayered coatings exhibited preferable adhesion properties in comparison with the multilayered *** electrochemical tests and XPS results imply that the monolayered Ni_(50)Nb_(50) MGC with high Nb content resisted corrosion mainly due to the formation of stable passive film that contained abundant Nb_(2)O_(5) species,whereas the Ni_(60)Nb_(40) MGC with high Ni content showed week corrosion protection performance during long-term service due to the dissolution of Ni cations and the devastation of the coating *** with bit worse adhesion and more vulnerable Ni_(60)Nb_(40) layers,the multilayered Ni_(50)Nb_(50)/Ni_(60)Nb_(40) MGC possessed comparable corrosion resistance with the monolayered Ni_(50)Nb_(50) MG coating,which remained stable even after 32 days of *** performance should be ascribed to the combined eff;ect of the repassivation property for the sub-layers,the hindrance of propagation paths of micro-defects,and the obstruction of corrosive species by interfaces in the multilayered coating.

关键词： Magnetron sputtering NiNb Metallic glasses Multilayer Corrosion protection