Device Design Requirements Research Articles

Octopus-inspired deception and signaling systems from an exceptionally-stable acene variant

Multifunctional platforms that can dynamically modulate their color and appearance have attracted attention for applications as varied as displays, signaling, camouflage, anti-counterfeiting, sensing, biomedical imaging, energy conservation, and robotics. Within this context, the development of camouflage systems with tunable spectroscopic and fluorescent properties that span the ultraviolet, visible, and near-infrared spectral regions has remained exceedingly challenging because of frequently competing materials and device design requirements. Herein, we draw inspiration from the unique blue rings of the Hapalochlaena lunulata octopus for the development of deception and signaling systems that resolve these critical challenges. As the active material, our actuator-type systems incorporate a readily-prepared and easily-processable nonacene-like molecule with an ambient-atmosphere stability that exceeds the state-of-the-art for comparable acenes by orders of magnitude. Devices from this active material feature a powerful and unique combination of advantages, including straightforward benchtop fabrication, competitive baseline performance metrics, robustness during cycling with the capacity for autonomous self-repair, and multiple dynamic multispectral operating modes. When considered together, the described exciting discoveries point to new scientific and technological opportunities in the areas of functional organic materials, reconfigurable soft actuators, and adaptive photonic systems.

Efficient field-circuit co-simulation method for GaN-based high power microwave devices

Due to the development of the third-generation semiconductors representative of gallium nitride (GaN), the microwave power devices are developing towards higher power, higher efficiency and high integration. However, the electromagnetic field effects are more significant inside the device. As a result, circuit-level based simulation techniques can no longer satisfy the accuracy requirements of device design. Therefore it is necessary to urgently establish the field-circuit co-simulation techniques to couple the active GaN devices with passive electromagnetic structures. In this work, we propose a high-precision discontinuous Galerkin time-domain method to analyze the performances of GAN-based high-power microwave devices. The extracted large-signal compact model of the GaN HEMT is incorporated into the electromagnetic field equations. A local time-stepping technique is adopted to remove the constraints of nonlinear compact models and multiscale elements on the stability conditions of the global algorithm. The comparisons among numerical simulations, experimental results, and software calculations demonstrate the excellent accuracy and efficiency of the proposed method, which can provide a theoretical analysis and design tool for the high reliability design of advanced high-power microwave devices.

The design of medical micro atomization device based on piezoelectric actuators

In this paper, there is much demand for more advanced inhaled drug treatment on respiratory diseases treatment, so we design and manufacture a kind of medical micro atomization device based on piezoelectric actuators. In the experiment, the first measuring method we used is the diameter of the fog particles compare with quartz round bead in 1 micron. The second measuring method is weighing bibulous desiccant. The experimental results show that the fog particles produced by micro atomization device is 3 ∼ 4 microns in diameter, and fog particles rate is 0.07 ∼ 0.08 g/min. These data basically meets medical micro atomization device design requirements for the diameter and flow rate of fog particles on respiratory diseases treatment.

Low-temperature sintering synthesis and electromagnetic properties of NiCuZn/BaTiO3 composite materials

In this study, various amounts of BaTiO3 ceramics (BTO) were introduced into Ni0.15Cu0.24Zn0.61Fe2O4 (NCZF) via solid-state reaction method and sintered at 920 °C with 2 wt% Bi2O3 addition. Obviously, the magnetic properties were affected violently but dielectric behaviors were improved, and the variations showed great regularity. We obtained composite materials with well magnetic and dielectric properties which can meet different design requirements of devices. To be specific, phase distribution and composition, microstructure morphology, magnetic and dielectric properties of these composites were systematically investigated via X-ray diffraction (XRD), scanning electron microscopy (SEM), and impedentiometry. XRD analysis results proved that the biphase (ferrite phase and ceramic phase) was produced successfully, whereas SEM micrographs revealed that grain size decreased with the content of BTO ceramic. Magnetic properties, such as saturation magnetization (4πMs), coercivity (Hc), permeability (μ′), and quality factor (Q) can vary with the amount of BTO ceramics. By adding BTO to NCZF, electrical properties, such as dielectric constant (ε′) and dielectric loss (tan δ) were remarkably improved. Indeed, when the content of BTO ceramics varied from 5 wt% to 10 wt%, so-prepared composites possess outstanding electromagnetic properties (μ′ > 50.5, Q > 60, ε′ ≈ 23.8, tan δ < 4.76 × 10−4). Therefore, these materials can be further exploited for the development of advanced integration, miniaturized, and multifunctional information system.

Development of a micromachined accelerometer for particle acceleration detection

We are reporting on the design, fabrication, and experimental results for a micromachiend accelerometer that is intended to be used in the detection of acoustic signals, where the main requirements include low noise, wide bandwidth, and high linearity. The device design requirements are discussed and analytically modelled. Microfabrication details to build prototypes are provided in detail. The final device structure employs membrane as the suspension mechanism and a proof-mass made from the entire thickness of a wafer that is suspended above a fixed electrode. The proposed manufacturing process allows for precise and independent control of the structural components of the device and the capacitive gap. Prototype devices were fabricated and characterized. Measurements on the device performance demonstrate a 0.6 μg/Hz noise floor with resonance frequency of 5.2 kHz, sensitivity of ∼0.9 pF/g, and open-loop dynamic range of higher than 145 dB while operating at atmospheric pressure. The device meets the requirements for measuring sonar signals in the range of 50 Hz to 5 kHz under low environmental noise conditions.

(Invited) Rare Earth Doped Light Emitting Thin Film Materials for Silicon Photonics

Silicon photonic technology is becoming ubiquitous for data center, sensing and advanced photonic applications. However, one of the key challenges for silicon photonic microsystems is integrating materials which can provide optical gain. The leading approach involves hybrid bonding of III-V materials to silicon chips, which is expensive and difficult to scale. Alternatively, rare-earth-doped materials are promising for active device applications on silicon. Rare earth doped oxide thin films can be deposited using standard, low-cost, and wafer-scale methods directly on silicon and emit light in important bands for communications and other emerging applications. This presentation will cover recent progress on integrating rare-earth-doped materials into silicon photonic microsystems. It will focus on fabrication and integration methods, particularly reactive magnetron co-sputtering, which yields low-loss, high-gain thin films which can be deposited using a single post-processing step onto silicon photonic chips that have been fabricated in a silicon foundry. The fabrication challenges, spectroscopic properties, and device design requirements related to prospective materials, including ytterbium-, erbium- and thulium-doped oxides will be discussed. The talk will review the application of such films in light-emitting rare-earth-doped devices, including amplifiers and continuous-wave and pulsed lasers.

Home Noninvasive Ventilation

Treatment of chronic respiratory failure with noninvasive ventilation (NIV) is standard pediatric practice, and NIV systems are commonly used in the home setting. Although practice guidelines on the perioperative management of children supported with home NIV systems have yet to be published, increasingly these patients are referred for consultation regarding perioperative management. Just as knowledge of pharmacology underlies the safe prescription of medication, so too knowledge of biomedical design is necessary for the safe prescription of NIV therapy. The medical device design requirements developed by the Organization for International Standardization provide a framework to rationalize the safe prescription of NIV for hospitalized patients supported at home with NIV systems. This review article provides an overview of the indications for home NIV therapy, an overview of the medical devices currently available to deliver it, and a specific discussion of the management conundrums confronting anesthesiologists.

Bistable Micro-Ring Lasers With Compact Footprint and High Output Efficiency

Micro-ring lasers, with a minimum bend radius of 10 $\mu{\rm m}$ , are presented that exhibit directional bistability and output powers up to 1.5 mW. In order to achieve devices with low threshold currents, mW output powers and directional bistability, the confilicting design constraints on the device are highlighted. Optimized adiabatic waveguide bends, bi-level evanescent couplers, and deeply etched ridge waveguide designs are presented in order to meet the stringent device design requirements. The optimized micro-ring laser devices exhibit directional extinction ratios of 25 dB and side-mode suppression ratios ${>}{\rm 25}~{\rm dB}$ .

Relationship between short channel behavior and long term stability of n-channel enhancement and depletion MOSFETs

Enhancement and depletion mode n-channel MOSFETs are investigated with respect to short channel effects and hot carrier related instabilities. It is found that subthreshold characteristics of normally off type devices are improved by additional deep channel implants. However, long term stability of enhancement mode devices decreases with the deep channel implant dose. A similar behavior is observed for depletion mode devices. Significant improvement in device stability can be realized using buried channel conduction. However, short channel effects attain untolerable magnitudes in devices with deep buried channels. It is concluded in this paper, that the conventional approaches used for optimization of long term stability and d.c. characteristics of small size MOSFETs are technologically incompatible. In the outlook, device design requirements are discussed to circumvent these problems.