Fabrication of Al matrix composite reinforced with submicrometer-sized Al<Subscript>2</Subscript>O<Subscript>3</Subscript> particles formed by combustion reaction between HEMM Al and V<Subscript>2</Subscript>O<Subscript>5</Subscript> composite particles during sintering

To fabricate an Al-V matrix composite reinforced with submicron-sized Al₂O₃ and Al_xV_y (Al₃V, Al₁₀V) phases, high energy mechanical milling (HEMM) and sintering were employed. By increasing the milling time, the size of mechanically milled powder was significantly reduced. In this study, the average powder size of 59 μm for Al, and 178 μm for V₂O₅ decreased with the formation of a new product, Al-Al₂O₃-Al_xV_y, with a size range from 1.3 μm to 2.6 μm formed by the in-situ combustion reaction during sintering of HEM milled Al and V₂O₅ composite powders. The in-situ reaction between Al and V₂O₅ during the HEMM and sintering transformed the Al₂O₃ and Al_xV_y (Al₃V, Al₁₀V) phases. Most of the reduced V reacted with excess the Al to form Al_xV_y (Al₃V, Al₁₀V) with very little V dissolved into Al matrix. By increasing the milling time and weight percentage of V₂O₅, the hardness of the Al-Al₂O₃-Al_xV_y composite sintered at 1173 K increased. The composite fabricated with the HEMM Al-20wt.%V₂O₅ composite powder and sintering at 1173 K for 2 h had the highest hardness.     

A reconfigurable microstrip antenna for switchable polarization

A novel reconfigurable microstrip antenna with switchable polarization sense is proposed. The proposed antenna has a simple structure, consisting of a corner-truncated square radiating patch, four small triangular conductors, and a microstrip line feed. Using independently biased PIN diodes on the patch, it can produce linear polarization, or left- or right-hand circular polarization according to bias voltages. From the measured results, low cross-polarization levels when operated in the linear state and good axial ratios in the circular state are observed.     

Stretchable,Transparent Zinc Oxide Thin Film Transistors

Stretchable and transparent thin film transistors (TFTs) with intrisically brittle oxide semiconductors are built using a wavy structural configuration that can provide high flexibility and stretchability. After device fabrication procedures including high temperature annealing, the oxide semiconductor‐based TFT arrays can be transferred directly to plastic or rubber substrates, without an additional device process, using transfer printing methods. This procedure can avoid some of the thermal degradation problems associated with plastic or rubber substrates by separating them from the annealing procedure needed to improve the device performance. These design and fabrication methods offer the possibility of developing a new format of stretchable electronics.     

Selective Photothermal Tumor Therapy Using Nanodiamond‐Based Nanoclusters with Folic Acid

This paper describes the fabrication and evaluation of folic acid (FA)‐conjugated nanodiamond (ND) nanoclusters for selective photothermal tumor therapy. ND nanoclusters with surface carboxyl groups are aminated using ethylenediamine and conjugated with FA via carbodiimide chemistry. The temperature of an aqueous ND dispersion (10 μg mL^?1) is increased to 54 °C upon laser exposure for 5 min. FA‐ND nanoclusters are preferentially taken up by KB cells (folate receptor positive) compared to WI‐38 (folate receptor negative) cells, suggesting specificity for tumor cells that overexpress folate receptors. Cell viability tests reveal that FA‐ND nanoclusters effectively and selectively ablate KB cells upon near‐infrared (NIR) laser exposure. In addition, fluorescence microscopy images confirm that only KB cells treated with FA‐ND nanoclusters are ablated in a spot (200 μm in diameter) by NIR laser exposure. In an animal model, a large amount of FA‐ND nanoclusters is accumulated into tumor tissue, resulting in dramatically reduced tumor volume post‐NIR laser exposure as compared to ND nanoclusters.     

Improved Scalar Multiplication on Elliptic Curves Defined over F2mn

We propose two improved scalar multiplication methods on elliptic curves over F_qn where q = 2^m using Frobenius expansion. The scalar multiplication of elliptic curves defined over subfield F_q can be sped up by Frobenius expansion. Previous methods are restricted to the case of a small m. However, when m is small, it is hard to find curves having good cryptographic properties. Our methods are suitable for curves defined over medium‐sized fields, that is, 10 ≤ m ≤ 20. These methods are variants of the conventional multiple‐base binary (MBB) method combined with the window method. One of our methods is for a polynomial basis representation with software implementation, and the other is for a normal basis representation with hardware implementation. Our software experiment shows that it is about 10% faster than the MBB method, which also uses Frobenius expansion, and about 20% faster than the Montgomery method, which is the fastest general method in polynomial basis implementation.     

Threshold‐Based Camera Motion Characterization of MPEG Video

We propose an efficient scheme for camera motion characterization in MPEG‐compressed video. The proposed scheme detects six types of basic camera motions through threshold‐based qualitative interpretation, in which fixed thresholds are applied to motion model parameters estimated from MPEG motion vectors (MVs). The efficiency and robustness of the scheme are validated by the experiment with real compressed video sequences.     

Detection of repolarization alternans with an implantable cardioverter defibrillator lead in a porcine model

Mechanistic links have been suggested between repolarization alternans (RPA) and the onset of ventricular tachycardia (VT) and/or fibrillation. Endocardial detection of RPA may, therefore, be an important step in future device-based treatments of arrhythmias. Here, we investigate if RPA could be detected during acute ischemia using an implantable cardioverter defibrillator (ICD) lead (tip to distal coil) located in the right ventricular apex. In 18 pigs, the right coronary (n = 10) or left anterior descending coronary (n = 8) artery was occluded for 10 min using a balloon catheter, followed by reperfusion for 30 min, and re-occlusion for 30 min. RPA magnitude, computed using the modified moving average (MMA) method, showed a sharp increase in all 18 animals, from a mean baseline level of 1.9 +/- 1.3 mV to 3.0 +/- 1.3 mV during first occlusion (p < 0.001). RPA magnitude showed a prominent increase in 10 animals during re-occlusion, from a mean baseline level of 1.7 +/- 1.0 mV to 3.3 +/- 1.5 mV (p < 0.001). The protocol was terminated during the first two stages of occlusion and reperfusion for the remaining 8 animals due to the occurrence of ventricular fibrillation (VF). These results confirm that RPA increases under ischemic conditions and that it is possible to detect and track RPA dynamics with an ICD lead that is positioned in a clinically realistic location. Such an approach may be useful in formulating improved arrhythmia detection and control algorithms.     

Decision feedback detection with error compensation for hybrid space-time block codes

Spatial division multiplexing (SDM) techniques increase the total throughput by transmitting independent information streams through multiple transmit antennas whereas space time coding (STC) techniques utilize diversity gain. Hybrid space-time block code (STBC) schemes proposed combine the above two techniques to maximize the link performance. We propose a decision feedback detection method to improve the performance of the hybrid STBC scheme for orthogonal frequency division multiplexing (OFDM). In this scheme, we take the error propagation effect into account to enhance the detection performance. Simulation results show that the proposed method outperforms the conventional hybrid STBC detection algorithm by more than 3dB at 1% frame error rate for frequency selective fading channels.     

Suppression of transient phenomena in hybrid Raman/EDF amplifier

Transient phenomena of hybrid Raman/erbium-doped fiber amplifier (EDFA) upon optical channel add-drop are investigated. The transient responses of surviving channels are resulted from the combined dynamics of Raman amplifier and EDFA. It is shown that the suggested method employing fast gain control of EDFA only can effectively suppress the transient variation of output power. The transient-suppressing hybrid Raman/EDFA is proven to be enough for wavelength-division-multiplexing networks including reconfigurable optical add-drop multiplexer and/or transparent optical cross-connect, if the optical switching speed is carefully chosen.     

Metalorganic Chemical Vapor Deposition of CdTe(133) Epilayers on Si(211) Substrates

Single-crystalline CdTe(133) films have been grown by metalorganic chemical vapor deposition on Si(211) substrates. We studied the effect of various growth parameters on the surface morphology and structural quality of CdTe films. Proper oxide removal from the Si substrate is considered to be the principal factor that influences both the morphology and epitaxial quality of the CdTe films. In order to obtain single-crystalline CdTe(133) films, a two-stage growth method was used, i.e., a low-temperature buffer layer step and a high- temperature growth step. Even when the low-temperature buffer layer shows polycrystalline structure, the overgrown layer shows single-crystalline structure. During the subsequent high-temperature growth, two-dimensional crystallites grow faster than other, randomly distributed crystallites in the buffer layer. This is because the capturing of adatoms by steps occurs more easily due to increased adatom mobility. From the viewpoint of crystallographic orientation, it is assumed that the surface structure of Si(211) consists of (111) terrace and (100) step planes with an interplanar angle of 54.8°. This surface structure may provide many preferable nucleation sites for adatoms compared with nominally flat Si(100) or (111) surfaces. The surface morphology of the resulting films shows macroscopic rectangular-shaped terrace—step structures that are considered to be a (111) terrace with two {112} step planes directed toward 〈110〉.