357 research outputs found
Kinetics Study of Adsorption Behaviors of Trivalent Metal Ions onto Chelating Resin: Comparison between Scandium(III) and Other Metal Ions
Scandium (Sc) lacks commercially viable independent deposits and is mainly recovered as a by-product of the smelting of other ores. In the process of recovering nickel from laterite ores, Sc is recovered from leaching solutions. The recovery of Sc requires its efficient separation and purification from other impurities. This study proposes a process for the selective separation and recovery of Sc from other trivalent cations in sulfuric acid solutions using an iminodiacetic acid chelating resin, Diaion™ CR11. The adsorption behaviors of trivalent ions Sc(III), Cr(III), Al(III), and Fe(III) onto CR11 in single- and multiple-metal systems were investigated to determine the appropriate Sc separation conditions. In systems containing single metal ions, pseudo-first-order and pseudo-second-order kinetic models were used to fit the data. Linear and nonlinear methods were used for fitting. The activation energies were calculated from the rate constants at a pH of 2.0 and at three different temperatures of 23℃, 60℃, and 80℃ and followed the order: Cr(III) > Fe(III) > Sc(III) > Al(III). In binary systems including Sc(III), the simultaneous adsorption of Sc(III) and other trivalent ions onto CR11 was investigated. Previously adsorbed Sc(III) on CR11 was displaced by the subsequent adsorption of Fe(III) or Cr(III) from the solution. The affinity of the metal ions to iminodiacetic acid and the adsorption reaction rate were critical factors for suitable selective Sc separation, indicating that prior removal of Fe(III) was necessary. Column experiments at 23℃ using a synthetic solution without Fe(III) showed that Cr(III) adsorption was suppressed, and that Sc(III) was efficiently adsorbed. Scandium can be efficiently recovered from a solution containing Sc(III) after prior removal of Fe(III) by adsorption at low temperature using CR11
Point Cloud Denoising and Outlier Detection with Local Geometric Structure by Dynamic Graph CNN
The digitalization of society is rapidly developing toward the realization of
the digital twin and metaverse. In particular, point clouds are attracting
attention as a media format for 3D space. Point cloud data is contaminated with
noise and outliers due to measurement errors. Therefore, denoising and outlier
detection are necessary for point cloud processing. Among them, PointCleanNet
is an effective method for point cloud denoising and outlier detection.
However, it does not consider the local geometric structure of the patch. We
solve this problem by applying two types of graph convolutional layer designed
based on the Dynamic Graph CNN. Experimental results show that the proposed
methods outperform the conventional method in AUPR, which indicates outlier
detection accuracy, and Chamfer Distance, which indicates denoising accuracy.Comment: 2023 IEEE 12th Global Conference on Consumer Electronics (GCCE 2023
Nonlinear optical responses in noncentrosymmetric superconductors
The unique nonreciprocal responses of superconductors, which stem from the
Cooper pairs' quantum condensation, have been attracting attention. Recently,
theories of the second-order nonlinear response in noncentrosymmetric
superconductors were formulated based on the Bogoliubov-de Gennes theory. In
this paper, we study the mechanism and condition for second-order optical
responses of time-reversal symmetric superconductors. The numerical results
show the characteristic photocurrent and second harmonic generation in the
superconducting state. However, the superconductivity-induced nonlinear optical
responses disappear under some conditions on pair potential. We show that the
coexistence of intraband and interband pairing is necessary for the
second-order superconducting optical responses. In addition, the
superconducting Berry curvature factor, which is related to a component of
Berry curvature in the superconducting state, is essential for the nonlinear
responses. Thus, we derived the microscopic conditions where the
superconducting nonlinear response appears.Comment: 21 pages and 9 figure
Nonlinear optical responses in superconductors under magnetic fields: quantum geometry and topological superconductivity
Noncentrosymmetric superconductors offer fascinating phenomena of quantum
transport and optics such as nonreciprocal and nonlinear responses.
Time-reversal symmetry breaking often plays an essential role in the emergence
and enhancement of nonreciprocal transport. In this paper, we show the
nonreciprocal optical responses in noncentrosymmetric superconductors arising
from time-reversal symmetry breaking by demonstrating them in -wave
superconductors with a Rashba spin-orbit coupling and a magnetic field.
Numerical results reveal the superconductivity-induced bulk photocurrent and
second harmonic generation, which are forbidden at the zero magnetic field. We
discuss the properties and mechanisms of the superconducting nonlinear
responses emerging under the magnetic field. In particular, we investigate the
magnetic-field dependence of the photocurrent conductivity and clarify the
essential ingredients which give a contribution unique to superconductors under
the magnetic field. This contribution is dominant in the low carrier density
regime although the corresponding joint density of states is tiny. We attribute
the enhancement to the quantum geometry. Moreover, the nonlinear conductivity
shows peculiar sign reversal at the transition to the topological
superconducting state. We propose a bulk probe of topological transition and
quantum geometry in superconductors.Comment: 36 pages, 21 figure
Molecular Rheology of Glassy Polymers (FUNDAMENTAL MATERIAL PROPERTIES-Molecular Rheology)
Molecular origin of the viscoelasticity around the glass transition zone is investigated by means of dynamic birefringence and dynamic viscoelasticity measurements. The present study show that the viscoelasticity around the glass transition zone has two molecular origins: One is the orientation relaxation of main chain axis and the other one is the rotational motion of structure units about the main chain axis
Sign change in c-axis thermal expansion and lattice collapse by Ni substitution in Co1-xNixZr2 superconductors
We investigated the structural, electronic, and superconducting properties of
Co1-xNixZr2, in which c-axis thermal expansion is systematically controlled. At
x (smaller than) 0.3, c-axis negative thermal expansion (NTE) was observed, and
the thermal expansion constant {\alpha}c approached zero with increasing x. At
x = 0.4-0.6, zero thermal expansion was observed, and positive thermal
expansion (PTE) appeared for x (greater than) 0.7. By analyzing the c/a ratio,
we observed a possible collapsed transition in the tetragonal lattice at around
x = 0.6-0.8. The lattice collapse results in c-axis PTE and the suppression of
bulk superconductivity.Comment: 16 pages, 5 figures, 1 table, Supporting material
Clinical Experience Using a Real Time Autofluorescence Endoscopy System in the Gastrointestinal Tract
Autofluorescence spectra of neoplastic tissues have been reported to be significantly different
from those of normal tissues when excited by blue or violet light. From this concept, a light-induced
autofluorescence endoscopic imaging system for gastrointestinal mucosa (LIFE-GI;
Xillix, Canada and Olympus, Japan) has been newly developed and the clinical evaluation of
the prototype system has been conducted in hospitals in Canada, Netherlands and Japan
The First Bipartisan Privacy Bill in the United States“ American Data Privacy and Protection Act” ―Its Submission progress and Features―
departmental bulletin pape
EVALUATION OF TORQUE MOMENT IN ESTHETIC BRACKETS
Objectives: To examine the torque moment that occurs between esthetic brackets and bendable alloy (stainless steel [SS], titanium-molybdenum [Ti-Mo], and titanium-niobium [Ti-Nb]) wires.
Materials and Methods: This study examined ceramic (CR), zirconium oxide (ZC), polycarbonate (PC), and conventional metallic brackets (MT) (upper, 0.018-inch and 0.022-inch slots) combined with SS, Ti-Mo, and Ti-Nb wires using elastic module ligation. The torque moments delivered by various wire and bracket combinations were measured using a torque gauge apparatus. The wire torque angles at 5–40° were examined.
Results: The torque value increased in the order of CR, ZC, MT, and PC brackets for both 0.018-inch and 0.022-inch slots. The fracture points of the CR and ZC brackets combined with SS and Ti-Mo wires were approximately more than 30° and 35°, respectively. No fracture points were detected in the combination of ZC brackets and Ti-Nb wires.
Conclusions: The current study identified the material characteristics of CR, ZR, and PC brackets during torque tooth movements. The present results demonstrate a characteristic combined effect between different esthetic brackets and bendable alloy wires
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