Optical hyperdimensional soft sensing: Speckle-based touch interface and tactile sensor

Hyperdimensional computing (HDC) is an emerging computing paradigm that exploits the distributed representation of input data in a hyperdimensional space, the dimensions of which are typically between 1,000--10,000. The hyperdimensional distributed representation enables energy-efficient, low-latency, and noise-robust computations with low-precision and basic arithmetic operations. In this study, we propose optical hyperdimensional distributed representations based on laser speckles for adaptive, efficient, and low-latency optical sensor processing. In the proposed approach, sensory information is optically mapped into a hyperdimensional space with >250,000 dimensions, enabling HDC-based cognitive processing. We use this approach for the processing of a soft-touch interface and a tactile sensor and demonstrate to achieve high accuracy of touch or tactile recognition while significantly reducing training data amount and computational burdens, compared with previous machine-learning-based sensing approaches. Furthermore, we show that this approach enables adaptive recalibration to keep high accuracy even under different conditions.Comment: 11 pages, 9 figure

Optical skin: Sensor-integration-free multimodal flexible sensing

The biological skin enables animals to sense various stimuli. Extensive efforts have been made recently to develop smart skin-like sensors to extend the capabilities of biological skins; however, simultaneous sensing of several types of stimuli in a large area remains challenging because this requires large-scale sensor integration with numerous wire connections. We propose a simple, highly sensitive, and multimodal sensing approach, which does not require integrating multiple sensors. The proposed approach is based on an optical interference technique, which can encode the information of various stimuli as a spatial pattern. In contrast to the existing approach, the proposed approach, combined with a deep neural network, enables us to freely select the sensing mode according to our purpose. As a key example, we demonstrate simultaneous sensing mode of three different physical quantities, contact force, contact location, and temperature, using a single soft material without requiring complex integration. Another unique property of the proposed approach is spatially continuous sensing with ultrahigh resolution of few tens of micrometers, which enables identifying the shape of the object in contact. Furthermore, we present a haptic soft device for a human-machine interface. The proposed approach encourages the development of high-performance optical skins.Comment: 13 pages, 11 figure

X-ray absorption measurements at a bending magnet beamline with an Everhart–Thornley detector: A monolayer of Ho₃N@C₈₀ on graphene

X-ray Absorption Spectroscopy (XAS) is used for measuring monolayer quantities of Ho[Formula: see text]N@C[Formula: see text] endofullerene molecules on graphene at a low flux bending magnet beamline. The total electron yield is measured with an Everhart–Thornley detector. In comparison to sample current measurements with the same noise level, our approach reduces data acquisition time and radiation dose by a factor of 25. As the first application of this setup, we report temperature-dependent measurements of the Ho M[Formula: see text] edge with per mille accuracy. This documents the advantages and capabilities of an Everhart–Thornely detector for XAS measurements under low x-ray flux

An efficient synthesis of procyanidins. Rare earth metal Lewis acid catalyzed equimolar condensation of catechin and epicatechin

ArticleTETRAHEDRON LETTERS. 48(33): 5891-5894 (2007)journal articl

Inferring the Dy-N axis orientation in adsorbed DySc2_2N@C80_{80} endofullerenes by linearly polarized x-ray absorption spectroscopy

Endofullerene DySc$_2$N@C$_{80}$ is a single-molecule magnet with a large magnetic anisotropy and high blocking temperature, which is promising for nanomagnetic applications. As the easy axis of magnetization coincides with the Dy-N bond direction, it is important to understand the structure of the DySc$_2$N unit in the fullerene cage and to control the orientation of the molecules. Here we report on the experimental determination of Dy-N axis by x-ray absorption spectroscopy (XAS) with linear polarized light at the Dy−M$_{4,5}$ white lines. DySc$_2$N@C$_{80}$ molecules were adsorbed on a Pt(111) surface and XAS was performed as a function of temperature in the range between 35 and 300 K. The M$_5$/M$_4$ branching ratio shows a clear and reversible variation with temperature which can be explained, on the basis of a thermodynamic model, by a change of average orientation of the molecules with temperature. The XAS spectra are well reproduced by ligand field multiplet calculations. It is shown that the angle between the magnetization (Dy-N) axis and the surface plane can be directly inferred from the XAS spectra with in-plane polarization by comparison with calculated spectra. It is found that the endohedral unit is randomly oriented at room temperature but tends towards orientation parallel to the surface at low temperature, indicating a weak but non-negligible interaction between the endohedral units and the metal surface

AN EFFICIENT SYNTHESIS OF PROCYANIDINS USING EQUIMOLAR CONDENSATION OF CATECHIN AND/OR EPICATECHIN CATALYZED BY YTTERBIUM TRIFLATE

Stereoselective synthesis of catechin and epicatechin dimers under intermolecular condensation of equimolar amount of catechin derivatives catalyzed by Yb(OTf)(3). The coupled products were successfully converted to procyanidins B1, B2, B3, and B4, respectively. Procyanidins B1, B2, B3, and B4 could be used as standard compounds for identifying the polyphenols in natural source.ArticleHETEROCYCLES. 79:549-563 (2009)journal articl

Monolayer calibration of endofullerenes with x-ray absorption from implanted keV ion doses

X-ray absorption spectroscopy (XAS) has the highest sensitivity for chemical element detection on surfaces. With this approach, small amounts of lanthanide-containing endofullerene molecules (Ho3N@C80) have been measured by total electron yield at a low flux bending magnet beamline. The monolayer coverage is calibrated by extrapolating the signals of constant doses (3×1014 cm−2) of Ho ions implanted into SiO2 with energies between 2 and 115 keV. At room temperature, the Ho XAS spectra of the molecules and implanted ions indicate trivalent but not identical Ho ground states. Still, this approach demonstrates a way for calibration of small coverages of molecules containing open core-shell elements

Effects of NR1I2 and ABCB1 Genetic Polymorphisms on Everolimus Pharmacokinetics in Japanese Renal Transplant Patients

The purpose of this study was to evaluate the effects of NR1I2 (7635G>A and 8055C>T) and ABCB1 (1236C>T, 2677G>T/A, and 3435C>T) genetic polymorphisms on everolimus pharmacokinetics in 98 Japanese renal transplant patients. On day 15 after everolimus administration, blood samples were collected just prior to and 1, 2, 3, 4, 6, 9, and 12 h after administration. The dose-adjusted area under the blood concentration-time curve (AUC(0-12)) of everolimus was significantly lower in patients with the NR1I2 8055C/C genotype than in those with other genotypes (p = 0.022) and was significantly higher in male patients than female patients (p = 0.045). Significant correlations between the dose-adjusted AUC(0-12) of everolimus and age (p = 0.001), aspartate transaminase (p = 0.001), and alanine transaminase (p = 0.005) were found. In multivariate analysis, aging (p = 0.008) and higher alanine transaminase levels (p = 0.032) were independently predictive of a higher dose-adjusted everolimus AUC(0-12). Aging and hepatic dysfunction in patients may need to be considered when evaluating dose reductions in everolimus. In renal transplant patients, management using everolimus blood concentrations after administration may be more important than analysis of NR1I2 8055C>T polymorphism before administration

Nanosized and metastable molybdenum oxides as negative electrode materials for durable high-energy aqueous Li-ion batteries

The development of inherently safe energy devices is a key challenge, and aqueous Li-ion batteries draw large attention for this purpose. Due to the narrow electrochemical stable potential window of aqueous electrolytes, the energy density and the selection of negative electrode materials are significantly limited. For achieving durable and high-energy aqueous Li-ion batteries, the development of negative electrode materials exhibiting a large capacity and low potential without triggering decomposition of water is crucial. Herein, a type of a negative electrode material (i.e., LixNb2/7Mo3/7O2) is proposed for high-energy aqueous Li-ion batteries. LixNb2/7Mo3/7O2 delivers a large capacity of similar to 170 mA . h . g(-1) with a low operating potential range of 1.9 to 2.8 versus Li/Li+ in 21 m lithium bis(trifluoromethanesulfonyl)amide (LiTFSA) aqueous electrolyte. A full cell consisting of Li1.05Mn1.95O4/Li9/7Nb2/7Mo3/7O2 presents high energy density of 107 W . h . kg(-1) as the maximum value in 21 m LiTFSA aqueous electrolyte, and 73% in capacity retention is achieved after 2,000 cycles. Furthermore, hard X-ray photoelectron spectroscopy study reveals that a protective surface layer is formed at the surface of the negative electrode, by which the high-energy and durable aqueous batteries are realized with LixNb2/7Mo3/7O2. This work combines a high capacity with a safe negative electrode material through delivering the Mo-based oxide with unique nanosized and metastable characters.journal articl