Optimal Electrode Configurations for External Cardiac Pacing and Defibrillation: An Inhomogeneous Study

We have developed an inhomogeneous two-dimensional finite element computer model of the human torso, and have used it to study electrode performance in defibrillation and external cardiac pacing. Gross individual organ effects were assessed first for different electrode configurations by creating models which included one organ at a time, and comparing the results to those obtained with a homogeneous body. Electrode placement on the body was varied in order to determine, within the limitations of the model, optimal electrode configurations for external cardiac pacing and defibrillation. Finally, the electrical and geometric parameters of a previously proposed plate electrode design were optimized for the selected external pacing position. It was found that organs of extreme resistivity, close to the body surface, and within the direct current path between two electrodes, tended to have dominant effects on the surface current density distributions. The optimum pacing position is to place the driven electrode directly over the heart and the receiving electrode on the left lateral chest wall. For defibrillation, the driven electrode is moved to the right of the sternum.     

Defibrillation Recovery Curves for Different Electrode Materials

We tested 16 electrode materials for their electrical characteristics and normalized all results to a 1 cm2 area. The electrode pair impedance versus frequency from 5 to 2000 Hz ranged from 20 to 58 000 ?. We passed 2 mC through them in less than 5 ms to simulate defibrillation discharge. The resulting recovery curves showed voltage offsets after 5 s of from 300 to 800 mV.     

Decoding, Performance Analysis, and Optimal Signal Designs for Coordinate Interleaved Orthogonal Designs

Space-time block codes (STBC) using coordinate interleaved orthogonal designs (CIOD) proposed recently by Khan and Rajan allow single-complex symbol decoding and offer higher data rates than orthogonal STBC. In this paper, we present the channel decoupling property of CIOD codes. A new general maximum likelihood method is derived, enabling the calculation of the symbol pair-wise error probability and union bound (UB) on symbol error rate (SER). Extensive simulation results show that the UB is within 0.1 dB from the simulated SER when SER < 10^-2. The UB thus can be used to accurately predict and optimize the performance of CIOD codes. Furthermore, a new signal design combining signal rotation and power allocation is presented for constellations with uneven powers of real and imaginary parts such as rectangular quadrature amplitude modulation.     

Periodic Conductivity as a Mechanism for Cardiac Stimulation and Defibrillation

This study examines the distribution of the transmembrane potential in the periodic strand of cardiac muscle established by configurations of sources similar to those arising during extracellular stimulation and defibrillation, during intracellular stimulation, and during propagation of action potential. The closed-form solution indicates that during extracellular stimulation with large current and during defibrillation, the periodic component of the transmembrane potential is very important. We postulate that this periodic component causes the depolarization or defibrillation in cardiac muscle, which is different from the depolarization mechanism for a continuous fiber. On the other hand, during propagation and intracellular stimulation, the periodic component only slightly modifies the monotonic decrease of the transmembrane potential, which suggests that the mechanism of propagation in discrete structures may be similar to that of the continuous fiber.     

激光修整埋入无源元件的最佳设计

当设计具有埋入无源元件的PCB时,必须仔细考虑影响修整生产率和准确性的因素,而采用激光修整是最佳的。     

波导调制器的最佳电极设计

本文考虑了平行条形电极对单波导的折射率的最佳影响.并讨论了在一对条形电极下面的平行波导的最佳位置,它决定于电光晶体的光轴和电极间距.     

固体膜外电极型LCD平板背光源

为了进一步提高内部无电极型LCD平板背光源的发光亮度及其使用寿命,制备了一种利用固体IT0导电薄膜为导电介质的等离子体激发发光平板背光源.该电光源由两片平板玻璃中间充入纯氙气密封而成,光源内表面上各涂敷一层荧光粉,在玻璃板的外表面上用透明导电胶粘上一层ITO(氧化铟锡)导电薄膜为导电介质,以1.1 mm厚的玻璃板作为介质阻挡放电层,在高频交变电压的作用下产生等离子体,激发荧光粉发光.其最大发光亮度可达4 500 ed/m2,可持续发光5 000 h,最佳激发频率10.0 kHz,发光均匀度大于92%.     

Criteria for Optimal Averaging of Cardiac Signals

The averaging process is modeled as a linear system whose low-pass filter characteristics are determined by the degree in temporal misalignment of signals. Assuming the errors in temporal alignment of successive cardiac cycles are random, then the model transfer function is equivalent to the probability density function. The response of the model to a step input is equivalent to the probability distribution function, which can be readily quantified. To validate the model, a high resolution ECG amplifier and QRS recognition system was constructed that synchronizes a step input with a point on the QRS. Design criteria for optimal amplification, filtering, and triggering of the ECG are determined. Test of the model reveals a close correspondence between observed and predicted step responses. From the average step response, the recording fidelity of any average can be determined-rapidly while the alignment is adjusted for optimal precision. Using ECG signals from patients, our model system demonstrates that alignment errors can both add and subtract signal components. Methods for estimating the extent of signal distortion induced by averaging as well as criteria for minimizing it are presented.     

Optical Enhancement via Electrode Designs for High‐Performance Polymer Solar Cells

To capture the essence of the rapid progress in optical engineering exploited in high‐performance polymer solar cells (PSCs), a comprehensive overview focusing on recent developments and achievements in PSC electrode engineering is provided in this review. To date, various kinds of electrode materials and geometries are exploited to enhance light‐trapping in devices through distinct optical strategies. In addition to the widely used nanostructured electrodes that induce plasmonic‐enhanced light absorption, planar ultra‐thin metal films also have attracted significant attention due to their remarkably reflective transparent properties that beget efficient optical microcavities. These microcavities confine incident light with resonant frequencies between two reflective electrodes due to optically coherent interference, boosting the light absorption of thin‐film PSCs while maintaining efficient charge dissociation and extraction. After reviewing the challenges in developing high‐performance microcavity‐enhanced PSCs (MCPSCs), we discuss strategies to improve MCPSC performance further to showcase the potential of harnessing microcavity resonance effects in thin‐film PSCs.     

DefibViz: A Visualization Tool for the Assessment of Electrode Parameters on Transthoracic Defibrillation Thresholds

DefibViz is a software application developed for defibrillation simulation and visualization. It exploits both surface techniques and methods for the interactive exploration of volumetric datasets for the analysis of transthoracic defibrillation simulation results. DefibViz has a graphical user interface for the specification of the shape, size, position, and applied voltage of a defibrillator's electrodes. An option is provided for using 3D slice plane widgets, which operate on the volumetric datasets, such that the distribution of the voltage gradient induced by an electric shock can be visually inspected in various tissues throughout the myocardium and torso. One goal of DefibViz is to enhance understanding of how electrode parameters relate to the change of the voltage gradient distribution throughout the heart, which may help lead to optimal defibrillator design. DefibViz is significant, in that, it is built by using an open-source graphics and visualization framework providing a platform for subsequent modifiability and extensibility. Moreover, it integrates simulation and visualization techniques, which previously required the running of several independent software executables, into an enhanced, seamless, and comprehensive software application.     

Recent Advances in Rational Electrode Designs for High‐Performance Alkaline Rechargeable Batteries

In recent years, noticeable progress is achieved regarding alkaline rechargeable batteries (ARBs). Due to their merits of safety and low cost, ARBs are considered promising energy storage sources for large‐scale grid energy storage, electric vehicles, and hybrid electric vehicles, as well as wearable and portable devices. While previous reviews have focused on specific topics associated with ARBs, providing a comprehensive review on rechargeable alkaline batteries is both timely and worthwhile. In this review, the recent progress in ARBs is summarized and the strategies underlying rational electrode designs for cathodes and anodes are highlighted, as well as their applications in full cells including flexible batteries. This review may pave the way for further designs of high‐performance alkaline batteries.     

Two Methods for Optimal MECG Elimination and FECG Detection from Skin Electrode Signals

Two signal processing techniques for the suppression of the maternal ECG and simultaneously optimal detection of fetal ECG with respect to noise are presented. Both techniques are based on the singular value decomposition of a measurement matrix. Criteria are given in order to evaluate, a priori, electrode locations and sampling schemes for both methods. A fundamental difference with other methods is that the number of linearly independent FECG signals is not constrained to one. One of the presented techniques is a typical offline method. It is well suited for a large number of electrodes and large number of samples, which results in a better signal to noise ratio. The second technique is a typical on-line method. It gives fetal ECG signals within about 1 s, and is adaptive to changes of the transfer (e.g., due to fetal movement). It can be applied with a small number of electrodes (e.g., eight). It is shown that if three of these signals are from thoracic electrodes, the MECG suppression is guaranteed.     

Designs for Ultra-Tiny, Special-Purpose Nanoelectronic Circuits

Designs and simulation results are given for two small, special-purpose nanoelectronic circuits. The area of special-purpose nanoelectronics has not been given much consideration previously, though much effort has been devoted to the development of general-purpose nanoelectronic systems, i.e., nanocomputers. This paper demonstrates via simulation that the nanodevices and nanofabrication techniques developed recently for general-purpose nanocomputers also might be applied with substantial benefit to implement less complex nanocircuits targeted at specific applications. Nanocircuits considered here are a digital controller for the leg motion on an autonomous millimeter-scale robot and an analog nanocircuit for amplification of signals in a tiny optoelectronic sensor or receiver. Simulations of both nanocircuit designs show significant improvement over microelectronic designs in metrics such as footprint area and power consumption. These improvements are obtained from designs employing nanodevices and nanofabrication techniques that already have been demonstrated experimentally. Thus, the results presented here suggest that such improvements might be realized in the near term for important, special-purpose applications.     

逆变器创新设计解决方案——采用免焊接的压接式管脚、双联封装结构和输出电流电阻取样的方式

本文介绍了逆变器创新设计解决方案。新型的免焊接式自动压接技术(PressFIT)不仅缩短了模块装配时间,同时还提高了装配的强度和连接的可靠性。     

Electrocapacitive Deionization: Mechanisms,Electrodes, and Cell Designs

Capacitive deionization (CDI) is an emerging water desalination technology for removing different ionic species from water, which is based on electric charge compensation by these charged species. CDI is becoming popular because it is more energy-efficient and cost-effective than other technologies, such as reverse osmosis and distillation, specifically in dealing with brackish water having low or moderate salt concentrations. Over the past decade, the CDI research field has witnessed significant advances in the used electrode materials, cell architectures, and associated mechanisms for desalination applications. This review article first discusses ion storage/removal mechanisms in carbon and Faradaic materials aided by advanced in situ analysis techniques and computations. It then summarizes research progress toward electrode materials in terms of structure, surface chemistry, and composition. More still, it discusses CDI cell architectures by highlighting their different cell design concepts. Finally, current challenges and future research directions are summarized to provide guidelines for future CDI research.     

Wire Optimization for Multimedia SoC and SiP Designs

With advances in VLSI integration technology, a large number of hardware components can be integrated into a single chip. To provide the communication bandwidth for these components, existing bus-based interconnects often suffer from a large area occupied by a large number of bus signals. To address this issue, this paper proposes a new protocol for on-chip or in-package communication that is termed the System-on-Chip Network Protocol (SNP). SNP uses a small number of signals that are shared by address, control, and data information. Additional three-bit phase signals are used to distinguish the different information transmitted through a single set of SNP signals. Two sets of identical SNP signals form a symmetric communication channel that allow a master-to-master type of communication between hardware components. The phase signals facilitate the reduction of the communication time with phase interleaving and phase omission-restoration among successive transactions. The efficiency of SNP is evaluated by a static performance analysis as well as by simulations with register-transfer level models of SNP components. Both the analysis and simulation results show that the communication time with SNP is approximately a half that of Advanced Microcontroller Bus Architecture Advanced High-Performance Bus (AHB), although SNP has wires that are approximately three-fifths of AHB. MPEG-4 chips are implemented with both AHB and SNP, respectively, and it is observed from the MPEG-4 implementations that SNP requires less area for communication compared to AHB.      

High-Level Test Synthesis for Behavioral and Structural Designs

High-Level Test Synthesis (HLTS), a term introduced in recent years, promises automatic enhancement of testability of a circuit. In this paper we will show how HLTS can achieve higher testability for BIST-oriented test methodologies. Our results show considering testability during high-level synthesis, better testability can be obtained when compared to DFT at low level. Transformation for testability, which allows behavioral modification for testability, is a very powerful HLTS technique.     

Materials,Mechanics Designs,and Bioresorbable Multisensor Platforms for Pressure Monitoring in the Intracranial Space

Pressures in the intracranial, intraocular, and intravascular spaces are important parameters in assessing patients with a range of conditions, of particular relevance to those recovering from injuries or from surgical procedures. Compared with conventional devices, sensors that disappear by natural processes of bioresorption offer advantages in this context, by eliminating the costs and risks associated with retrieval. A class of bioresorbable pressure sensor that is capable of operational lifetimes as long as several weeks and physical lifetimes as short as several months, as combined metrics that represent improvements over recently reported alternatives, is presented. Key advances include the use of 1) membranes of monocrystalline silicon and blends of natural wax materials to encapsulate the devices across their top surfaces and perimeter edge regions, respectively, 2) mechanical architectures to yield stable operation as the encapsulation materials dissolve and disappear, and 3) additional sensors to detect the onset of penetration of biofluids into the active sensing areas. Studies that involve monitoring of intracranial pressures in rat models over periods of up to 3 weeks demonstrate levels of performance that match those of nonresorbable clinical standards. Many of the concepts reported here have broad applicability to other classes of bioresorbable technologies.