A Wireless Power Transfer Based Implantable ECG Monitoring Device

Implantable medical devices (IMDs) enable patients to monitor their health anytime and receive treatment anywhere. However, due to the limited capacity of a battery, their functionalities are restricted, and the devices may not achieve their intended potential fully. The most promising way to solve this limited capacity problem is wireless power transfer (WPT) technology. In this study, a WPT based implantable electrocardiogram (ECG) monitoring device that continuously records ECG data has been proposed, and its effectiveness is verified through an animal experiment using a rat model. Our proposed device is designed to be of size 24 x 27 x 8 mm, and it is small enough to be implanted in the rat. The device transmits data continuously using a low power Bluetooth Low Energy (BLE) communication technology. To charge the battery wirelessly, transmitting (Tx) and receiving (Rx) antennas were designed and fabricated. The animal experiment results clearly showed that our WPT system enables the device to monitor the ECG of a heart in various conditions continuously, while transmitting all ECG data in real-time.11Ysciescopu

Design and Implementation of a Wireless Charging-Based Cardiac Monitoring System Focused on Temperature Reduction and Robust Power Transfer Efficiency

Wireless power transfer systems are increasingly used as a means of charging implantable medical devices. However, the heat or thermal radiation from the wireless power transfer system can be harmful to biological tissue. In this research, we designed and implemented a wireless power transfer system-based implantable medical device with low thermal radiation, achieving 44.5% coil-to-coil efficiency. To suppress thermal radiation from the transmitting coil during charging, we minimized the ESR value of the transmitting coil. To increase power transfer efficiency, a ferrite film was applied on the receiving part. Based on analyses, we fabricated a cardiac monitoring system with dimensions of 17 x 24 x 8 mm(3) and implanted it in a rat. We confirmed that the temperature of the wireless charging device increased by only 2 degrees C during the 70 min charging, which makes it safe enough to use as an implantable medical device charging system.11Ysciescopu

A Nonlinear Optimization Model of Advertising Budget Allocation across Multiple Digital Media Channels

The goal of advertisers in the digital marketing industry is to optimize their advertising budgets. Such a budget allocation problem plays a key role in maximizing advertising performance from different marketing channels under planned advertising investment. This study aimed to design a budget-performance-based nonlinear programming model to find an optimized solution for the advertising budget allocation problem. The empirical analysis results of a leading e-business company’s advertising performance data show that the proposed non-LP model generates an optimized solution. The proposed model allows marketers to simulate expected advertising returns, such as conversions or revenues from different channels within their budget constraints

VIBRATIONAL CASE STUDY FOR THE MOLD OSCILLATOR WITH HYDRAULIC SERVO SYSTEM

We have conducted sensitivity analysis to investigate the two-hydraulic-servo system for the mold oscillator. By modelling mathematical models for operating fluid flow to control a hydraulic cylinder, we changed design parameters and environment conditions including friction, additional spring stiffness and fluid leakage. From the one-hydraulic servo system to the two-hydraulic cylinder, modal analysis was conducted to figure out dynamic characteristics of the real system. Especially, we categorized important natural mode shape. When the system was excited into the natural frequency, the 1st mechanical natural frequency could cause a pressure gain by reducing internal pressure of a hydraulic cylinder, but other natural frequencies were critically dangerous by generating imbalance, over-vibration and distortion. By comparing the results to the experimental data, we could find a dramatic pressure drop near 3 Hz oscillation when the system has the 1st mechanical natural frequency 2.499 Hz. Also, the system has the imbalance near 6 Hz oscillation when the system has 2nd mechanical natural frequency 5.446 Hz. Based on these fact, we have suggested some tips to oscillate a mold efficiently and safely

VIBRATIONAL CASE STUDY FOR THE MOLD OSCILLATOR WITH HYDRAULIC SERVO SYSTEM

We have conducted sensitivity analysis to investigate the two-hydraulic-servo system for the mold oscillator. By modelling mathematical models for operating fluid flow to control a hydraulic cylinder, we changed design parameters and environment conditions including friction, additional spring stiffness and fluid leakage. From the one-hydraulic servo system to the two-hydraulic cylinder, modal analysis was conducted to figure out dynamic characteristics of the real system. Especially, we categorized important natural mode shape. When the system was excited into the natural frequency, the 1st mechanical natural frequency could cause a pressure gain by reducing internal pressure of a hydraulic cylinder, but other natural frequencies were critically dangerous by generating imbalance, over-vibration and distortion. By comparing the results to the experimental data, we could find a dramatic pressure drop near 3 Hz oscillation when the system has the 1st mechanical natural frequency 2.499 Hz. Also, the system has the imbalance near 6 Hz oscillation when the system has 2nd mechanical natural frequency 5.446 Hz. Based on these fact, we have suggested some tips to oscillate a mold efficiently and safely

Entropically driven self-assembly of a strained hexanuclear indium metal-organic macrocycle and its behavior in solution

The self-assembly of a polyprotic pentadentate ligand, N-cyclopentanoylaminobenzoylhydrazide (H4L4), and an In(III) nitrate hydrate in methanol led to a strained hexanuclear indium metal-organic macrocycle (In-MOM), [In(III)(6)(H2L4)(6)(NO3)(x)(solvent)(6-x)](NO3)(6-x) (where, the solvent is either methanol or a water molecule and x is the number of the nitrate anions ligated). The ligand in the doubly deprotonated state serves as an unsymmetric linear ditopic donor and the alternating indium ions in two different chelation modes serve as two different bent ditopic metal acceptors, which led to a D-3-symmetric hexanuclear In-MOM. Although the hexanuclear In-MOM is enthalpically unfavorable because of the ring strain, the combination of the soft coordination characteristic of the indium ion and the slight ligand deformation from the conjugated planar conformation allows the formation of the entropically favored hexanuclear In-MOM rather than the enthalpically favored octanuclear In-MOM. While the hexanuclear In-MOM is stable in acetonitrile, it partially dissociates into its components in dimethylsulfoxide, and then slowly reaches a new equilibrium state with several different indium species yet to be identified in addition to the free ligand.close4

Single crystalline hollow metal-organic frameworks: a metal-organic polyhedron single crystal as a sacrificial template

Single crystalline hollow metal-organic frameworks (MOFs) with cavity dimensions on the order of several micrometers and hundreds of micrometers were prepared using a metal-organic polyhedron single crystal as a sacrificial hard template. The hollow nature of the MOF crystal was confirmed by scanning electron microscopy of the crystal sliced using a focused ion beam.open2

Long-Range Orbital Transport in Ferromagnets

While it is often assumed that the orbital transport is short-ranged due to strong crystal field potential and orbital quenching, we show that orbital propagation can be remarkably long-ranged in ferromagnets. In contrast to spin transport, which exhibits an oscillatory decaying behavior by spin dephasing, the injected orbital angular momentum does not oscillate and decays slowly. This unusual feature is attributed to nearly degenerate states in $\mathbf{k}$-space, which form hot-spots for the intrinsic orbital response. We demonstrate this in a bilayer consisting of a nonmagnet and a ferromagnet, where the orbital Hall current is injected from a nonmagnet into a ferromagnet. Interaction of the orbital Hall current with the magnetization in the ferromagnet results in an intrinsic response of the orbital angular momentum which propagates far beyond the spin dephasing length. This gives rise to a distinct type of orbital torque on the magnetization, increasing with the thickness of the ferromagnet. Such behavior may serve as critical long-sought evidence of orbital transport to be directly tested in experiments. Our findings open the possibility of using long-range orbital transport in orbitronic device applications

Optical transitions of a single nodal ring in SrAs3_3: radially and axially resolved characterization

We perform polarized optical reflection measurements on a single nodal-ring semimetal $\rm{SrAs_3}$. For the radial and axial directions of the ring, the optical conductivity $\sigma_1(\omega)$ exhibits a flat absorption $\sigma^{\mathrm{flat}}$ over a certain frequency range. In addition, a prominent optical peak appears at 2$\Delta_{\mathrm{SOC}}$ = 30 meV. For comparison, we theoretically calculate $\sigma_1(\omega)$ using an effective model Hamiltonian and first-principles calculations, which successfully reproduces the data for both directions. The $\sigma^{\mathrm{flat}}$ establishes that the universal power-law of optical conductivity holds robustly in the nodal ring. Furthermore, key quantities of the nodal ring such as the band overlap energy, average ring radius, ring ellipticity, and the SOC-gap are determined from this comparative study. As temperature increases, $\sigma_1(\omega)$ shows a substantial change, suggesting that a $T$-driven evolution occurs in the nodal ring.Comment: 6 pages, 4 figures + supplemental material (18 pages, 7 figures