Clean surfaces of (001)-oriented Er1Ba2Cu3O7?δ, Er5Ba7Cu12Oy, and Er4Ba5Cu9Oy high-temperature superconductor thin films were studied by photoemission spectroscopy using high-energy ultraviolet photons (hν in the 50...
Clean surfaces of (001)-oriented Er1Ba2Cu3O7?δ, Er5Ba7Cu12Oy, and Er4Ba5Cu9Oy high-temperature superconductor thin films were studied by photoemission spectroscopy using high-energy ultraviolet photons (hν in the 50 to 200 eV range). The surfaces were cleaned by heating in an ultrahigh-vacuum electron spectrometer at 400°C (or 350°C) in 1 × 10?3 Torr oxygen. Valence bands and outer core levels were studied. Ba 4d and Ba 5p doublet photopeaks showed spin-orbit splitting of 2.6 and 2.2 eV, respectively, as expected. Er, Ba, Cu, and O features in the valence band were identified.
We report the characterization of self-assembled epitaxially grown transition metal, Fe, Co, Ni, silicide nanowires （TM-NW） growth and electrical transport properties. NWs grown by reactive deposition epitaxy on var...
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We report the characterization of self-assembled epitaxially grown transition metal, Fe, Co, Ni, silicide nanowires （TM-NW） growth and electrical transport properties. NWs grown by reactive deposition epitaxy on various silicon surfaces show a dimension of 10nm by 5nm, and several micrometers in length. NW orientations strongly depend on substrate crystal orientation, and follow the substrate symmetry. By using conductive-AFM （c-AFM）, the electron transport properties of one single NW were measured, the resistivity of crystalline nickel silicide NW was estimated to be 2×10-2Ω＆#12539;cm.
Equal-channel angular pressing （ECAP） is a prominent technique that imposes severe plastic deformation into materials to en- hance their mechanical properties. In this research, experimental and numerical approaches...
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Equal-channel angular pressing （ECAP） is a prominent technique that imposes severe plastic deformation into materials to en- hance their mechanical properties. In this research, experimental and numerical approaches were utilized to investigate the mechanical prop- erties, strain behavior, and damage prediction of ECAPed 7025 aluminum alloy in various conditions, such as die channel angle, outer comer angle, and friction coefficient. Experimental results indicate that, after the first pass, the yield strength, ultimate tensile strength, and hardness magnitude are improved by approximately 95%, 28%, and 48.5%, respectively, compared with the annealed state, mainly due to grain re- finement during the deformation. Finite element analysis shows that the influence of die channel angle is more important than that of outer comer angle or friction coefficient on both the strain behavior and the damage prediction. Also, surface cracks are the main cause of damage during the ECAP process for every die channel angle except for 90°; however, the cracks initiated from the neighborhood of the central re- gions are the possible cause of damage in the ECAPed sample with the die channel angle of 90°.
Carbon monoxide is commonly encountered in energy systems, yet its reactivity with structural alloys—critical heat-resistant components in these systems—has been largely overlooked compared to the well-documented ef...
Carbon monoxide is commonly encountered in energy systems, yet its reactivity with structural alloys—critical heat-resistant components in these systems—has been largely overlooked compared to the well-documented effects of oxidizing gases. In contrast, we demonstrate the high-temperature reaction of CO with NiAl using in-situ low-energy electron microscopy and X-ray photoemission electron microscopy. Our results show that CO dissociates into atomic oxygen and carbon, resulting in two concurrent reactions: selective oxidation of aluminum to form Al 2 O 3 and the initiation of dusting corrosion through carbon dissolution into the alloy and subsequent carbon deposition on the surface. These reactions produce spatially distinct surface products, preventing the formation of a continuous protective Al oxide layer. These results reveal a preference for the dissociative pathway of CO over the classic Boudouard disproportionation reaction that forms CO 2 . These insights not only advance our understanding of CO-induced alloy degradation but also highlight the practical implications for managing alloy stability and optimizing catalysis in carbon-rich environments, such as those in petrochemical processing and hydrocarbon combustion.
Shear bands introduced into the as-quenched metallic glass alloy, MetglasR 2826 (Fe40Ni40P14B6), were etched by immersion in a solution of CUS04 and HCI. Elimination of the etchability property through isothermal anne...
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Shear bands introduced into the as-quenched metallic glass alloy, MetglasR 2826 (Fe40Ni40P14B6), were etched by immersion in a solution of CUS04 and HCI. Elimination of the etchability property through isothermal annealing had an apparent activation enthalpy of 250 kJ mol?1, similar to that of stress relaxation. Direct microscopic observations indicated that the etching of shear bands may be a result of stress corrosion cracking. The electrochemical etchability of shear bands in the nickel-based alloy, BNi2 (Ni68.8Cr6.6Fe2.6B14.1Si7.9), polarized in a solution of perchloric acid and acetic acid at 12° C, could also be eliminated by thermal annealing. The loss of etchability had an apparent activation enthalpy of 580 kJ mol?1, a value indicative of more complex atomic rearrangements taking place within the deformed material. Finally, shear bands introduced into the as-received BNi2 material retained the ability to reverse shear after heat treatment at temperatures in the range of 192 to 375° C even if the electrolytic etchability was apparently diminished.
Porous copper was produced by electrolytic dealloying of a Cu-Mn alloy (Incramute: Cu, 40-48 wt. % Mn, 1.4-2.3 wt. % Al) conducted in a 0.3 N-NaCl solution at a potential of -0.2 V (SCE). The dealloying time needed fo...
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Porous copper was produced by electrolytic dealloying of a Cu-Mn alloy (Incramute: Cu, 40-48 wt. % Mn, 1.4-2.3 wt. % Al) conducted in a 0.3 N-NaCl solution at a potential of -0.2 V (SCE). The dealloying time needed for the as-received cold-rolled specimen (50 h) is shorter than that of the annealed specimen (850 degrees C for 2 h). The pore size, about 1 mu m, of the dealloyed cold-rolled specimen is bigger than that, about 0.1 mu m, of the dealloyed specimen after annealing. This is probably because annealing reduced the phase inhomogeneity and removed the rolling effects.
Lithium ion batteries have revolutionized the portable electronics market, and they are being intensively pursued now for transportation and stationary storage of renewable energies like solar and wind. The success of...
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Lithium ion batteries have revolutionized the portable electronics market, and they are being intensively pursued now for transportation and stationary storage of renewable energies like solar and wind. The success of lithium ion technology for the latter applications will depend largely on the cost, safety, cycle life, energy, and power, which are in turn controlled by the component materials used. Accordingly, this Perspective focuses on the challenges and prospects associated with the electrode materials. Specifically, the issues associated with high-voltage and high-capacity cathodes as well as high-capacity anodes and the approaches to overcome them are presented.
Solar-driven atmospheric water harvesting (AWH) presents a sustainable approach for freshwater production with sunlight as the sole energy input. To address challenges posed by diurnal moisture variations and diffusiv...
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By decoupling temperature and flow fields through symmetry-correlated laser scan sequences,ISO-FLUCS enables quasi-isothermal optofluidic microscale *** technique offers precise control over fluid manipulation while m...
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By decoupling temperature and flow fields through symmetry-correlated laser scan sequences,ISO-FLUCS enables quasi-isothermal optofluidic microscale *** technique offers precise control over fluid manipulation while minimizing thermal damage.
To control the power hierarchy design of lithium?ion battery（LIB） built?up sets for electric vehicles（EVs）, we o er intensive theoretical and experimental sets of choice anode/cathode architectonics that can be mo...
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To control the power hierarchy design of lithium?ion battery（LIB） built?up sets for electric vehicles（EVs）, we o er intensive theoretical and experimental sets of choice anode/cathode architectonics that can be modulated in full?scale LIB built?up models. As primary structural tectonics, heterogeneous composite superstructures of full?cell?LIB（anode//cathode） electrodes were designed in closely packed flower agave rosettes TiO2@C（FRTO@C anode） and vertical?star?tower L iFePO4@C（VST@C cath?ode） building blocks to regulate the electron/ion movement in the three?dimensional axes and orientation pathways. The superpower hierarchy surfaces and multi?directional orientation components may create isosurface potential electrodes with mobile electron movements, in?to?out interplay electron dominances, and electron/charge cloud distribu?tions. This study is the first to evaluate the hotkeys of choice anode/cathode architectonics to assemble di erent LIB–electrode platforms with high?mobility electron/ion flows and high?performance capacity functionalities. Density functional theory calculation revealed that the FRTO@C anode and VST?（i）@C cathode architectonics are a superior choice for the configuration of full?scale LIB built?up models. The integrated FRTO@C//VST?（i）@C full?scale LIB retains a huge discharge capac?ity（～ 94.2%）, an average Coulombic e ciency of 99.85% after 2000 cycles at 1 C, and a high energy density of 127 Wh kg-1, thereby satisfying scale?up commercial EV requirements.
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