Comprehensive investigations of superconductivity in the charge-doped high-temperature superconducting cuprates often involve examining the evolution of physical properties within a series of samples having controlled...
Comprehensive investigations of superconductivity in the charge-doped high-temperature superconducting cuprates often involve examining the evolution of physical properties within a series of samples having controlled variations of some dopant element—most frequently oxygen. Many important observations have been extracted from such experiments, however, the associated measurements are by nature discrete snapshots of the evolving material. We demonstrate here a novel approach to sample preparation of the high-Tc cuprate YBa2Cu3Ox. By post-annealing a uniformly overdoped YBa2Cu3Ox(x≈7.0) film in a low pressure O2 atmosphere with a thermal gradient across the film length, we have successfully grown a charge-gradient YBa2Cu3O∇x sample, i.e., a film having a varying oxygen doping level along the length of the substrate. Surprisingly, we observe three distinct regimes of oxygen distribution across the sample, as well as behavior pointing to a full alignment within the a-b plane.
Flow mixing is an important process for many microfluidic applications. Efficient mixing is difficult in microscale channels owing to laminar flow. Disturbing the flow stream by modifying channel geometries or embeddi...
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Flow mixing is an important process for many microfluidic applications. Efficient mixing is difficult in microscale channels owing to laminar flow. Disturbing the flow stream by modifying channel geometries or embedding barriers improves the mixing rate. In this study, a three-dimensional (3-D) passive micromixer with propeller blades fabricated by two-photon polymerization (TPP) technology is embedded in the channel for fluid mixing. The propeller blades are designed to disturb the laminar flow in three dimensions to improve the mixing rate. Screw-shaped and flat blades are compared. The experimental results indicate that the screw-shaped propeller provides additional streamlines in the Z direction, which enhances the mixing efficiency. Finally, this phenomenon was verified through simulation.
Dense packings of nonoverlapping bodies in three-dimensional Euclidean space R3 are useful models of the structure of a variety of many-particle systems that arise in the physical and biological sciences. Here we inve...
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Dense packings of nonoverlapping bodies in three-dimensional Euclidean space R3 are useful models of the structure of a variety of many-particle systems that arise in the physical and biological sciences. Here we investigate the packing behavior of congruent ring tori in R3, which are multiply connected nonconvex bodies of genus 1, as well as horn and spindle tori. Specifically, we analytically construct a family of dense periodic packings of unlinked tori guided by the organizing principles originally devised for simply connected solid bodies [Torquato and Jiao, Phys. Rev. E 86, 011102 (2012)]. We find that the horn tori as well as certain spindle and ring tori can achieve a packing density not only higher than that of spheres (i.e., π/18=0.7404...) but also higher than the densest known ellipsoid packings (i.e., 0.7707...). In addition, we study dense packings of clusters of pair-linked ring tori (i.e., Hopf links), which can possess much higher densities than corresponding packings consisting of unlinked tori.
A key capability of focused ion beam (FIB) tools is the ability to deposit conductive materials by introducing organometallic precursors such as tungsten hexacarbonyl [W(CO)6] or (methylcyclopentadienl) trimethyl plat...
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Single-crystalline p-n junctions with contacting two single-crystals of organic semiconductors are expected to show superior charge transport property as well as exciton generation/dissociation abi
Single-crystalline p-n junctions with contacting two single-crystals of organic semiconductors are expected to show superior charge transport property as well as exciton generation/dissociation abi
Single-crystalline p-n junctions with contacting two single-crystals of organic semiconductors are expected to show superior charge transport property as well as exciton generation/dissociation ***,the single-crystall...
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Single-crystalline p-n junctions with contacting two single-crystals of organic semiconductors are expected to show superior charge transport property as well as exciton generation/dissociation ***,the single-crystalline p-n junctions are difficult to ***,crystallization generally requires relatively clean environments and crystallization of"p"and"n"two components together tends to interrupt each ***,we describe how to grow,from solutions,organic singlecrystalline p-n junctions in a single step from a mixed solution of p-type and n-type
Single-crystalline p-n junctions with contacting two single-crystals of organic semiconductors are expected to show superior charge transport property as well as exciton generation/dissociation ***,these p-n junctions...
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Single-crystalline p-n junctions with contacting two single-crystals of organic semiconductors are expected to show superior charge transport property as well as exciton generation/dissociation ***,these p-n junctions are promising high-performance materials for opto-electronic applications such as solar cells.
Equal channel angular pressing method is one of the prominent severe plastic deformation techniques to obtain ultrafine grained and even nanostructured metals and alloys by imposing intense plastic strain. As known, p...
Equal channel angular pressing method is one of the prominent severe plastic deformation techniques to obtain ultrafine grained and even nanostructured metals and alloys by imposing intense plastic strain. As known, pure titanium can be a suitable candidate for biomedical applications because it does not release any toxic ions into the body fluids and also, its biocompatibility properties. The present investigation deals the corrosion behavior of commercial pure titanium before and after ECAP process up to 10 passes by route BC at the 250°C in the 0.9% NaCl solution. The electrochemical results revealed that the corrosion resistance of titanium sample is improved by adding pass number because of the fabrication of passive oxide layer on the surface of the material. It is found that about 92% reduction at the corrosion rate magnitude and also, approximately 41% improvement at the hardness value have been achieved at the final pass as compared to the annealed condition. Furthermore, it is observed that the passive film on the surface of final pass sample is dense and integral with uniform structure, while the as-received one has some rarefactions and does not have very uniform surface.
Proton‐coupled electron‐transfer oxidation of a Ru II −OH 2 complex, having an N‐heterocyclic carbene ligand, gives a Ru III −O . species, which has an electronically equivalent structure of the Ru IV =O species, i...
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Proton‐coupled electron‐transfer oxidation of a Ru II −OH 2 complex, having an N‐heterocyclic carbene ligand, gives a Ru III −O . species, which has an electronically equivalent structure of the Ru IV =O species, in an acidic aqueous solution. The Ru III −O . complex was characterized by spectroscopic methods and DFT calculations. The oxidation state of the Ru center was shown to be close to +3; the Ru−O bond showed a lower‐energy Raman scattering at 732 cm −1 and the Ru−O bond length was estimated to be 1.77(1) Å. The Ru III −O . complex exhibits high reactivity in substrate oxidation under catalytic conditions; particularly, benzaldehyde and the derivatives are oxidized to the corresponding benzoic acid through C−H abstraction from the formyl group by the Ru III −O . complex bearing a strong radical character as the active species.
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