Fabrication of antireflection structures on TCO film for reflective liquid crystal display

The cholesteric liquid crystals display (ChLCD) is one kind of reflective liquid crystal display, the antireflective layer on its transparent conduction oxides (TCO) film is needed for good contrast and color performance. In this study, the finite difference time domain (FDTD) simulation and nanoimprinting fabrication of AR structures on the TCO film are developed. Finally, the reflectance of AR structures on TCO film is just half of the original film, and this result is useful for the reflective ChLCD product commercialized in the future.     

A Distributed Localization Scheme for Wireless Sensor Networks with Improved Grid-Scan and Vector-Based Refinement

Localization is a fundamental and essential issue for wireless sensor networks (WSNs). Existing localization algorithms can be categorized as either range-based or range-free schemes. Range-based schemes are not suitable for WSNs because of their irregularity of radio propagation and their cost of additional devices. In contrast, range-free schemes do not need to use received signal strength to estimate distances and only need simple and cheap hardware, and are thus more suitable for WSNs. However, existing range-free schemes are too costly and not accurate enough or are not scalable. To improve previous work, we present a fully distributed range-free localization scheme for WSNs. We assume that only a few sensor nodes, called anchors, know their locations, and the remaining (normal) nodes need to estimate their own locations by gathering nearby neighboring information. We propose an improved grid-scan algorithm to find the estimated locations of the normal nodes. Furthermore, we derive a vector-based refinement scheme to improve the accuracy of the estimated locations. Analysis, simulation, and experiment results show that our scheme outperforms the other range-free schemes even when the communication radius is irregular.     

Differentiated Service Provision in Optical CDMA Network Using Power Control

A simple scheme to use power control for differentiated service provision is proposed for the optical code-division multiple-access network. The main advantages of this scheme are: 1) Interference from other users can be eliminated theoretically. 2) The decoder with simple configuration can be used as compared to that in a previous power control scheme. 3) The design procedure of various service requirements in one network is simplified.      

Using Sorted Switching Median Filter to remove high-density impulse noises

We propose a novel Sorted Switching Median Filter (i.e. SSMF) for effectively denoising extremely corrupted images while preserving the image details. The center pixel is considered as “uncorrupted” or “corrupted” noise in the detecting stage. The corrupted pixels that possess more noise-free surroundings will have higher processing priority in the SSMF sorting and filtering stages to rescue the heavily noisy neighbors. Five noise models are considered to assess the performance of the proposed SSMF algorithm. Several extensive simulation results conducted on both grayscale and color images with a wide range (from 10% to 90%) of noise corruption clearly show that the proposed SSMF substantially outperforms all other existing median-based filters.     

Design of low power UWB LNA based on common source topology with current-reused technique

This paper presents two low power UWB LNAs with common source topology. The power reduction is achieved by the current-reused technique. The gain and noise enhancement of the proposed circuit is based on an output buffer which is used by a common source amplifier with shunt–shunt feedback. Chip1 is an adopted T-match input network of 50 Ω matching in the required band. Measurements show that the S₁₁ and S₂₂ are less than −10 dB, and the maximum amplifier gain S₂₁ gives 9.7 dB, and the noise figure is 4.2 dB, the IIP3 is −8.5 dBm, and the power consumption is 11 mW from 1.1 V supply voltage. The input matching of chip2 is adopted from a LC high pass filter and source degenerated inductor. The output buffer with the RC-feedback topology can improve the gain, increase the IIP3, restrain the noise, improve the noise figure and decrease the DC power dissipation. Measurements show 13.2 dB of power gain, 3.33 dB of noise figure, and the IIP3 is −3.3 dBm. It consumes 9.3 mW from 1.5 V supply voltage. These two chips are implemented in a 0.18 μm TSMC CMOS process.     

Soldering of solution-processed organic vertical transistor and light-emitting diode on separate glass substrates by tin micro-balls

The vertical organic space-charge-limited transistor made of P3HT and small-molecule phosphorescent organic light-emitting diode (OLED) are made on two separate glass substrate by blade coating, then soldered vertically together by tin balls with 40 μm diameter. The soldering is done by hot wind of 150 °C for 5 min Contact resistance is only 10 Ω. The vertical transistor is annealed at 150 °C for 5 min before soldering to enhance the output current up to 25 mA/cm² and give high thermal stability. Both OLED and the annealed vertical transistor are not affected by the soldering process. The vertical transistor has 1/4 of the OLED area and turns on the bottom-emission white OLED up to 300 cd/m² and orange OLED up to 600 cd/m². The entire operation is within 8 V. OLED and transistor array can therefore be made on separate glass substrates then soldered together to form the display.     

Robust cerebellar model articulation controller design for unknown nonlinear systems

In this study, a robust cerebellar model articulation controller (RCMAC) is designed for unknown nonlinear systems. The RCMAC is comprised of a cerebellar model articulation controller (CMAC) and a robust controller. The CMAC is utilized to approximate an ideal controller, and the weights of the CMAC are on-line tuned by the derived adaptive law based on the Lyapunov sense. The robust controller is designed to guarantee a specified H/sup /spl infin// robust tracking performance. In the RCMAC design, the sliding-mode control method is utilized to derive the control law, so that the developed control scheme has more robustness against the uncertainty and approximation error. Finally, the proposed RCMAC is applied to control a chaotic circuit. Simulation results demonstrate that the proposed control scheme can achieve favorable tracking performance with unknown the controlled system dynamics.     

Adaptive decentralized control of robot manipulators driven by current-fed induction motors

In this paper, an adaptive decentralized control scheme with a rotor-flux observer is proposed for the tracking control of robot manipulators actuated by current-fed induction motors. To cope with all parametric uncertainties in the electromechanical systems, an adaptive law is designed so that all the signals of closed-loop systems are bounded, and the tracking errors in position, velocity and rotor fluxes converge to a residual set.     

Bipolar switching characteristics of low-power Geo resistive memory

We reported an ultra low-power resistive random access memory (RRAM) combining a low-cost Ni electrode and covalent-bond GeO_x dielectric. This cost-effective Ni/GeO_x/TaN RRAM device has very small set power of 2 μW, ultra-low reset power of 130 pW, greater than 1 order of magnitude resistance window, and stable retention at 85 °C. The current flow at low-resistance state is governed by Poole-Frenkel conduction with electrons hopping via defect traps, which is quite different from the filament conduction in metal-oxide RRAM.     

Dithienocarbazole‐Based Ladder‐Type Heptacyclic Arenes with Silicon,Carbon, and Nitrogen Bridges: Synthesis,Molecular Properties,Field‐Effect Transistors,and Photovoltaic Applications

A new class of ladder‐type dithienosilolo‐carbazole ( DTSC ), dithienopyrrolo‐carbazole ( DTPC ), and dithienocyclopenta‐carbazole ( DTCC ) units is developed in which two outer thiophene subunits are covalently fastened to the central 2,7‐carbazole cores by silicon, nitrogen, and carbon bridges, respectively. The heptacyclic multifused monomers are polymerized with the benzothiadiazole ( BT ) acceptor by palladium‐catalyzed cross‐coupling to afford three alternating donor‐acceptor copolymers poly(dithienosilolo‐carbazole‐alt‐benzothiadiazole) ( PDTSCBT) , poly(dithienocyclopenta‐carbazole‐alt‐benzothiadiazole) ( PDTCCBT), and poly(dithienopyrrolo‐carbazole‐alt‐benzothiadiazole) ( PDTPCBT) . The silole units in DTSC possess electron‐accepting ability that lowers the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of PDTSCBT , whereas stronger electron‐donating ability of the pyrrole moiety in DTPC increases the HOMO and LUMO energy levels of PDTPCBT . The optical bandgaps (E_g^opt) deduced from the absorption edges of thin film spectra are in the following order: PDTSCBT (1.83 eV) > PDTCCBT (1.64 eV) > PDTPCBT (1.50 eV). This result indicated that the donor strength of the heptacyclic arenes is in the order: DTPC > DTCC > DTSC . The devices based on PDTSCBT and PDTCCBT exhibited high hole mobilities of 0.073 and 0.110 cm² V^?1 s^?1, respectively, which are among the highest performance from the OFET devices based on the amorphous donor‐acceptor copolymers. The bulk heterojunction photovoltaic device using PDTSCBT as the p‐type material delivered a promising efficiency of 5.2% with an enhanced open circuit voltage, V_oc, of 0.82 V.