Wavelength and power stabilisation of uncooled 975 nm thick quantum well lasers over 110/spl deg/C temperature range

The use of a thick quantum well enables coherence-collapse operation of a Bragg grating stabilised laser diode over 110/spl deg/C temperature range, yielding 975 nm wavelength emission with >40 dB sidemode suppression ratio, <1% power variation, and fibre-output power as high as 293 mW at 15/spl deg/C and 168 mW at 125/spl deg/C.     

Functionally Antagonistic Hybrid Electrode with Hollow Tubular Graphene Mesh and Nitrogen‐Doped Crumpled Graphene for High‐Performance Ionic Soft Actuators

Ionic soft actuators, which exhibit large mechanical deformations under low electrical stimuli, are attracting attention in recent years with the advent of soft and wearable electronics. However, a key challenge for making high‐performance ionic soft actuators with large bending deformation and fast actuation speed is to develop a stretchable and flexible electrode having high electrical conductivity and electrochemical capacitance. Here, a functionally antagonistic hybrid electrode with hollow tubular graphene meshes and nitrogen‐doped crumpled graphene is newly reported for superior ionic soft actuators. Three‐dimensional network of hollow tubular graphene mesh provides high electrical conductivity and mechanically resilient functionality on whole electrode domain. On the contrary, nitrogen‐doped wrinkled graphene supplies ultrahigh capacitance and stretchability, which are indispensably required for improving electrochemical activity in ionic soft actuators. Present results show that the functionally antagonistic hybrid electrode greatly enhances the actuation performances of ionic soft actuators, resulting in much larger bending deformation up to 620%, ten times faster rise time and much lower phase delay in a broad range of input frequencies. This outstanding enhancement mostly attributes to exceptional properties and synergistic effects between hollow tubular graphene mesh and nitrogen‐doped crumpled graphene, which have functionally antagonistic roles in charge transfer and charge injection, respectively.     

A displacement measurement technique using millimeter-wave interferometry

A displacement measurement sensor, capable of sub-millimeter resolution, using millimeter-wave interferometry has been developed. The sensor operates at 37.6 GHz and is realized using both microwave integrated circuits and monolithic microwave integrated circuits. It has been used to accurately measure the displacement of metal plate location and water level. A resolution of only 0.05 mm is achieved. A maximum error of 0.3 mm is also attained without correction for the nonlinearity of the phase-detection processor and agrees well with the theoretical calculation.     

Very large temperature-induced absorptive loss in high Te-containing chalcogenide fibers

The change in the absorption loss relative to room temperature of the infrared (IR)-transmitting Ge/sub 15/As/sub 35/Se/sub (50-x)/Te/sub x/ glass fibers in the temperature range of -110/spl deg/C/spl les/T/spl les/110/spl deg/C was investigated. The attenuation increased significantly at T/spl ges/40/spl deg/C. This is mainly attributed to thermally activated free carriers associated with the semimetallic character of the Te atom. For /spl lambda//spl les/4.2 /spl mu/m, the loss due to electronic and free-carrier absorption was strongly affected by temperature. In the wavelength region of 5-11 /spl mu/m, the loss was mainly due to free-carrier absorption. Beyond /spl lambda//spl ges/11 /spl mu/m, multiphonon absorption dominated the loss spectrum at T/spl les/60/spl deg/C while free-carrier absorption contributed mainly to the total loss at T/spl ges/80/spl deg/C.     

LCD motion blur reduction: a signal processing approach.

Liquid crystal displays (LCDs) have shown great promise in the consumer market for their use as both computer and television displays. Despite their many advantages, the inherent sample-and-hold nature of LCD image formation results in a phenomenon known as motion blur. In this work, we develop a method for motion blur reduction using the Richardson-Lucy deconvolution algorithm in concert with motion vector information from the scene. We further refine our approach by introducing a perceptual significance metric that allows us to weight the amount of processing performed on different regions in the image. In addition, we analyze the role of motion vector errors in the quality of our resulting image. Perceptual tests indicate that our algorithm reduces the amount of perceivable motion blur in LCDs.     

High-mobility low band-to-band-tunneling strained-Germanium double-gate heterostructure FETs: Simulations

Large band-to-band tunneling (BTBT) leakage currents can ultimately limit the scalability of high-mobility (small-bandgap) materials. This paper presents a novel heterostructure double-gate FET (DGFET) that can significantly reduce BTBT leakage currents while retaining its high mobility, making it suitable for scaling into the sub-20-nm regime. In particular, through one-dimensional Poisson-Schrodinger, full-band Monte Carlo, and detailed BTBT simulations, the tradeoffs between carrier transport, electrostatics, and BTBT leakage in high-mobility sub-20-nm Si-strained SiGe-Si (high germanium concentration) heterostructure PMOS DGFETs are thoroughly analyzed. The results show a dramatic (>100/spl times/) reduction in BTBT and an excellent electrostatic control of the channel while maintaining very high drive currents and switching frequencies in these nanoscale transistors.     

Fuzzy sliding-mode controllers with applications

This paper concerns the design of robust control systems using sliding-mode control that incorporates a fuzzy tuning technique. The control law superposes equivalent control, switching control, and fuzzy control. An equivalent control law is first designed using pole placement. Switching control is then added to guarantee that the state reaches the sliding mode in the presence of parameter and disturbance uncertainties. Fuzzy tuning schemes are employed to improve control performance and to reduce chattering in the sliding mode. The practical application of fuzzy logic is proposed here as a computational-intelligence approach to engineering problems associated with sliding-mode controllers. The proposed method can have a number of industrial applications including the joint control of a hydraulically actuated mini-excavator as presented in this paper. The control hardware is described together with simulated and experimental results. High performance and attenuated chatter are achieved. The results obtained verify the validity of the proposed control approach to dynamic systems characterized by severe uncertainties     

Optimization of an RFID location identification scheme based on the neural network

An indoor localization technology is increasingly critical as location‐aware applications evolve. Researchers have proposed several indoor localization technologies. Because most of the proposed indoor localization technologies simply involve using the received signal strength indicator value of radio‐frequency identification (RFID) for indoor localization, radio‐frequency interference, and environmental factors often limit the accuracy of localization results. Therefore, this study proposes an accurate RFID localization based on the neural network (ARL‐N²), a passive RFID indoor localization scheme for identifying tag positions in a room, combining a location identification based on dynamic active RFID calibration algorithm with a backpropagation neural network (BPN). The proposed scheme composed of two phases: in the training phase, an appropriate BPN architecture is constructed using the training data derived from the coordinates of reference tags and the coordinates obtained using the localization algorithm. By contrast, the online phase involves calculating the tracking tag coordinates and using these values as BPN inputs, thereby enhancing the estimated location. A performance evaluation of the ARL‐N² schemes confirms its high localization accuracy. The proposed method can be used to locate critical objects in difficult‐to‐find areas by creating minimal errors and applying and economical technique. Copyright © 2013 John Wiley & Sons, Ltd.     

Low-power-consumption and high-gain CMOS distributed amplifiers using cascade of inductively coupled common-source gain cells for UWB systems

A distributed amplifier with new cascade inductively coupled common-source gain-cell configuration is presented. Compared with other existing gain-cell configurations, the proposed cascade common-source gain cell can provide much higher transconductance and, hence, gain. The new distributed amplifier using the proposed gain-cell configuration, fabricated via a TSMC 0.18-/spl mu/m CMOS process, achieves an average power gain of around 10 dB, input match of less than -20 dB, and noise figure of 3.3-6.1 dB with a power consumption of only 19.6 mW over the entire ultra-wideband (UWB) band of 3.1-10.6 GHz. This is the lowest power consumption ever reported for fabricated CMOS distributed amplifiers operating over the whole UWB band. In the high-gain operating mode that consumes 100 mW, the new CMOS distributed amplifier provides an unprecedented power gain of 16 dB with 3.2-6-dB noise figure over the UWB range.