Plasmon‐Induced Sub‐Bandgap Photodetection with Organic Schottky Diodes

Organic materials for near‐infrared (NIR) photodetection are in the focus for developing organic optical‐sensing devices. The choice of materials for bulk‐type organic photodetectors is limited due to effects like high nonradiative recombination rates for low‐gap materials. Here, an organic Schottky barrier photodetector with an integrated plasmonic nanohole electrode is proposed, enabling structure‐dependent, sub‐bandgap photodetection in the NIR. Photons are detected via internal photoemission (IPE) process over a metal/organic semiconductor Schottky barrier. The efficiency of IPE is improved by exciting localized surface plasmon resonances, which are further enhanced by coupling to an out‐of‐plane Fabry–Pérot cavity within the metal/organic/metal device configuration. The device allows large on/off ratio (>1000) and the selective control of individual pixels by modulating the Schottky barrier height. The concept opens up new design and application possibilities for organic NIR photodetectors.     

Composite hydrogeological investigation and characterisation methods applied at a nuclear power plant site in Taiwan

Drawing from the lessons learnt from the Fukushima nuclear disaster in Japan, the assessment of subsurface environmental hazard around nuclear power plants has emerged as a critical task. Consequently, aiming to better understand the possible environmental impact of radiation leaks into the groundwater, a prescreening programme was initiated in 2011 by the Taiwanese government. As part of this programme, this study conducted various borehole prospecting techniques to identify in situ hydrogeological characteristics at Chin‐Shan Nuclear Power Plant. Borehole electrical log, sonic log and temperature/conductivity log were conducted to explain the regional lithologic conditions and permeability of the formation. In conjunction with this, the interwell tracer and pumping test was carried out to simultaneously determine the hydraulic parameters. In our opinion, the implementation of such in situ end‐to‐end investigations is essential in interpreting in situ fluid and solute transport dynamics prior to programming any numerical scheme for early warning, vulnerability assessment and regular monitoring of a nuclear power plant site.     

Unprecedented Homoleptic Bis‐Tridentate Iridium(III) Phosphors: Facile,Scaled‐Up Production,and Superior Chemical Stability

Bis‐tridentate Ir(III) metal complexes are expected to show great potential in organic light‐emitting diode (OLED) applications due to the anticipated, superb chemical and photochemical stability. Unfortunately, their exploitation has long been hampered by lack of adequate methodology and with inferior synthetic yields. This hurdle can be overcome by design of the first homoleptic, bis‐tridentate Ir(III) complex [Ir(pzpyph)(pz^Hpyph)] ( 1 ), for which the abbreviation (pzpyph)H (or pz^Hpyph) stands for the parent 2‐pyrazolyl‐6‐phenyl pyridine chelate. After that, methylation and double methylation of 1 afford the charge‐neutral Ir(III) complex [Ir(pzpyph)(pz^Mepyph)] ( 2 ) and cationic complex [Ir(pz^Mepyph)₂][PF₆] ( 3 ), while deprotonation of 1 gives formation of anionic [Ir(pzpyph)₂][NBu₄] ( 4 ), all in high yields. These bis‐tridentate Ir(III) complexes 2 – 4 are highly emitted in solution and solid states, while the charge‐neutral 2 and corresponding t ‐butyl substituted derivative [Ir(pzpy^Buph)(pz^Mepy^Buph)] ( 5 ) exhibit superior photostability versus the tris‐bidentate references [Ir(ppy)₂(acac)] and [Ir(ppy)₃] in toluene under argon, making them ideal OLED emitters. For the track record, phosphor 5 gives very small efficiency roll‐off and excellent overall efficiencies of 20.7%, 66.8 cd A^?1, and 52.8 lm W^?1 at high brightness of 1000 cd m^?2. These results are expected to inspire further studies on the bis‐tridentate Ir(III) complexes, which are judged to be more stable than their tris‐bidentate counterparts from the entropic point of view.     

Cooperative detection and protection for Interest flooding attacks in named data networking

Named data networking (NDN) is a new emerging architecture for future network, which may be a substitute of the current TCP/IP‐based network, for the content‐oriented data request mode becoming the future trend of development. The security of NDN has attracted much attention, as an implementation of next‐generation Internet architecture. Although NDN is immune to most current attack, it cannot resist the distributed denial of service like attack – Interest flooding attack (IFA) – effectively. IFA takes advantages of the forwarding mechanism of NDN, flooding a large number of malicious Interest packets at quite a high rate, and exploits the network resources, which may cause the paralysis of the network. Taking into account the severity of the destruction, we propose an algorithm to counter such new type of attack. We analyze three properties of IFA, and use them to judge and filter Interest packets. Vector space model and Markov model are used in our method to realize a cooperative detection. Meanwhile, we present the retransmission forwarding mechanism to ensure legitimate user request. The ndnSIM module of ns3 is used for the corresponding simulation, and results of the simulation will be given to show the effectiveness of our algorithm. Copyright © 2014 John Wiley & Sons, Ltd.     

Dual‐Targeted Photopenetrative Delivery of Multiple Micelles/Hydrophobic Drugs by a Nanopea for Enhanced Tumor Therapy

A photoresponsive pea‐like capsule (nanopea) that also represents a photothermal agent is constructed by wrapping multiple polymer micelles (polyvinyl alcohol, PVA) in reduced graphene oxide nanoshells through a double emulsion approach. Resulting nanopeas can transport multiple PVA micelles containing the fully concealed hydrophobic drug docetaxel (DTX) which can be later released by a near‐infrared photoactuation trigger. Through integrating the rod‐shaped adhesion and lactoferrin (Lf) targeting, the nanopea enhances both uptake by cancer cellc in vitro and particle accumulation at tumor in vivo. A photopenetrative delivery of micelles/DTX to the tumor site is actuated by NIR irradiation which ruptures the nanopeas as well as releases nanosized micelles/DTX. This trigger also results in thermal damage to the tumor and increases the micelles/DTX permeability, facilitating drug penetration into the deep tumor far from blood vessels for thermal chemotherapy. This nanopea with the capability of imaging, enhanced tumor accumulation, NIR‐triggered tumor penetration, and hyperthermia ablation for photothermal chemotherapy boosts tumor treatment and shows potential for use in other biological applications.     

Performance comparisons of intelligent load forecasting structures and its application to energy-saving load regulation

This study mainly focuses on the development of intelligent forecasting structures via a similar time method with historical load change rates for the hourly, daily and monthly load forecasting simultaneously based on the basic frameworks of fuzzy neural network (FNN) and particle swarm optimization (PSO). In the regulative aspect of network parameters, conventional back-propagation (BP) and PSO tuning algorithms are used, and varied learning rates are designed in the sense of discrete-time Lyapunov stability theory. The performance comparisons of different intelligent forecasting structures including neural network (NN) structure with BP tuning algorithm (NN-BP), FNN structure with BP tuning algorithm (FNN-BP), FNN structure with BP tuning algorithm and varied learning rates (FNN-BP-V), FNN structure with PSO tuning algorithm (FNN-PSO) and newly-designed adaptive PSO (APSO) structure are verified by numerical simulations. In order to verify the effectiveness of the superior APSO forecasting structure in practical energy-saving load regulation, the load forecasting during every 15 min is also given, and its result is used to manipulate the scheduled unloading control of a real case in Taiwan campus.     

Analysis of a 0.1-μm stepping bi-axis piezoelectric stage using a 2-DOF lumped model

Piezoelectric stages are widely used for parts manipulation, including micro-component assembly and bio-cell manipulation. This paper proposes a bi-axis piezoelectric stage based on a friction driven mechanism. The carrier slides on a supporting frame and slider constructed in the same plane as a low-profile stage. The dynamic model of the friction driven is based on a 2-DOF lumped model considering the impact and separation behavior. The first mass is the bulk piezoelectric actuator (slab)—as a vibrator—and the second is the driven slider. The stiffness ratio of the piezoelectric slab-to-the driven slider affects the output force of the slider because of the contact time ratio. Moreover, the stepping size is adjusted according to the duty ratio of the pulse width of the driving signal. The stepping size of 0.1 μm is achieved in the X and Y axes corresponding to 3% and 5% of the duty ratio, respectively, of 512-Hz carrier frequency in 20-Vpp driving signal. When the duty ratio is 100%, the full speed of 18 and 16 mm/s are achieved in the X- and Y-axes, respectively. The dimensions of the piezoelectric stage are 61 × 58 × 21.3 (high) mm³.

     

Constraint-based Correspondence Matching for Stereo-based Interactive Robotic Massage Machine

Locating the 3D positions of the points on the human back is an essential issue in stereo-based interactive robotic back massage machines. In stereoscopic 3D localization, the 3D positions are determined from the corresponding image points captured by calibrated stereo cameras. However, detecting these corresponding points on the human back is highly challenging due to the smooth and texture-less characteristics of human skin. In the present study, this problem is resolved by means of a novel correspondences detection scheme designated as Correspondences from Epipolar geometry and Contours via Triangle barycentric coordinates (CECT). In the proposed approach, reliable correspondences are extracted from the edge contours of the human back by applying epipolar geometry, and these correspondences are then used to compute the correspondences of the featureless points within the edge contour using a triangle barycentric coordinate approach. The accuracy and robustness of the estimated correspondences are ensured by applying three geometric constraints, namely a similarity constraint, a shape constraint and an epipolar constraint. The performance of the proposed approach is demonstrated by means of a series of experiments involving 28 subjects and four different testing conditions. In addition, the accuracy of the proposed localization scheme is evaluated by comparing the estimated 3D positions with those obtained using the cun-based measurement method in Traditional Chinese Medicine (TCM).