Effects of temperature and vacancy defects on tensile deformation of single-walled carbon nanotubes

This study adopts the Tersoff-Brenner interaction potential function in a series of molecular dynamic (MD) simulations which investigate the mechanical properties under tensile loading of (10,0) zigzag, (8,3) chiral and (6,6) armchair single-walled carbon nanotubes (SWCNTs) of similar radii. The Young's modulus values of the (10,0), (8,3) and (6,6) nanotubes are determined to be approximately 0.92, 0.95, and 1.03 TPa, respectively. Of these nanotubes, the results reveal that the (6,6) nanotube possesses the best tensile strength and toughness properties under tension. Although it is noted that under small tensions, the mechanical properties such as Young's modulus are essentially insensitive to helicity, under larger plastic deformations, they may be influenced by helicity effects. Finally, the simulations demonstrate that the values of the majority of the considered mechanical properties decrease with increasing temperature and increasing vacancy percentage.     

NVM characteristics of single-MOSFET cells using nitride spacers with gate-to-drain NOI

This work presents the characteristics of a two-bit-per-cell charge-trapping nonvolatile memory (NVM) device by using gate-to-drain nonoverlapped implanted (NOI) n-MOSFETs. Hot carriers are generated in NOI devices and injected into the silicon nitride spacers. The characteristics of this potential single-transistor NVM cell, including two-bit operation, programming and erasing characteristics, are investigated. Their stability and reliability characteristics such as retention, disturbance and cycling are also evaluated.     

A full-wave analysis of microstrip lines by variational conformalmapping technique

Wheeler's mapping, which is useful in the quasi-TEM analysis of microstrip lines, is combined with the full-wave variational formulation to facilitate a finite-element solution. This desirable mapping not only transforms the problem domain into a finite region, but also overcomes the field singularity on the strip edge. Compared with other known techniques, the present method makes fewer assumptions, and is more rigorous as long as the strip thickness is negligible. Numerical results for the frequency dependence of effective dielectric constant, the characteristic impedance, and both longitudinal and transverse current distributions on the strip are also included     

A facile synthesis of unsymmetrical heterocyclic azines by cyclodesulfurization: Reaction of methyl arylalkylidenehydrazinecarbodithioates with diamines

A new and facile synthesis of unsymmetrical heterocyclic azines is described. Methyl arylalkylidenehydraz-inecarbodithioates, prepared by the condensation of ketones or aldehydes with methyl hydrazinecarbodithioate, were heated under reflux with various diamines in ethanol. Secondary diamines, such as N,N′-dimethyl-ethylenediamine, N,N′-dimethyl-1,3-diaminopropane or N,N′-dimethyl-o-phenylenediamine, reacted smoothly with loss of hydrogen sulfide to give good yields of unsymmetrical azines. However, primary diamines, such as ethylenediamine or o-phenylenediamine, and primary/secondary diamines, such as N-methylethyl-enediamine and N-methyl-1,3-diaminopropane gave, instead, only the corresponding uncyclized thiosemi-carbazones. A cyclodesulfurization mechanism for azine formation is discussed.     

High detectivity InGaN-GaN multiquantum well p-n junction photodiodes

InGaN-GaN multiquantum well (MQW) p-n junction photodiodes with semi-transparent Ni-Au electrodes were fabricated and characterized. It was found that the fabricated InGaN-GaN p-n junction photodiodes exhibit a 20-V breakdown voltage and a photocurrent to dark current contrast ratio of /spl sim/10/sup 5/ when a 0.4-V reverse bias was applied. The peak responsivity at 380 nm was 1.28 and 1.76 A/W with a 0.1- and 3-V applied reverse bias, respectively. Furthermore, an internal gain was found from our InGaN-GaN MQW p-n junction photodiodes possibly due to the long-lifetime of GaN based materials. Also, it was found that the low frequency noise of our photodiodes was dominated by the 1/f type noise. For a given bandwidth of 500 Hz, the corresponding noise equivalent power and normalized detectivity D/sup */ were found to be 6.34/spl times/10/sup -13/ W and 4.45/spl times/10/sup 11/ cm/spl middot/Hz/sup 0.5/ W/sup -1/, respectively.     

Knowledge model based approach in recognition of on-line Chinesecharacters

A knowledge model-based OCR system is presented for the recognition of on-line connected stroke Chinese characters. In the approach, segment attributes are first extracted to characterize the segment sequence of an unknown character. Next, radical recognition based on model matching is adopted as the coarse classification to reduce the number of candidate characters before detailed matching. Finally, a deviation modeling method is proposed to recognize not only regular writing characters but also characters with stroke-order and stroke-number deviations. The effectiveness of the approach is verified by experiments on the recognition of on-line Chinese characters     

A Novel Moisture‐Insensitive and Low‐Corrosivity Ionic Liquid Electrolyte for Rechargeable Aluminum Batteries

Rechargeable aluminum batteries (RABs) are extensively developed due to their cost‐effectiveness, eco‐friendliness, and low flammability and the earth abundance of their electrode materials. However, the commonly used RAB ionic liquid (IL) electrolyte is highly moisture‐sensitive and corrosive. To address these problems, a 4‐ethylpyridine/AlCl₃ IL is proposed. The effects of the AlCl₃ to 4‐ethylpyridine molar ratio on the electrode charge–discharge properties are systematically examined. A maximum graphite capacity of 95 mAh g^?1 is obtained at 25 mA g^?1. After 1000 charge–discharge cycles, ≈85% of the initial capacity can be retained. In situ synchrotron X‐ray diffraction is employed to examine the electrode reaction mechanism. In addition, low corrosion rates of Al, Cu, Ni, and carbon‐fiber paper electrodes are confirmed in the 4‐ethylpyridine/AlCl₃ IL. When opened to the ambient atmosphere, the measured capacity of the graphite cathode is only slightly lower than that found in a N₂‐filled glove box; moreover, the capacity retention upon 100 cycles is as high as 75%. The results clearly indicate the great potential of this electrolyte for practical RAB applications.     

Autonomic Navigation System Based on Predicted Traffic and VANETs

To avoid an expected traffic jam, drivers make detours based on limited information; however, the majority following the alike routes may result in an unexpected congestion. Conventional navigation approaches are unable to respond to the unexpected congestion because these approaches do not consider the routes taken by other vehicles. Navigation systems that utilize global traffic information can improve gas consumption, CO₂ emissions and travel time. Therefore, in this paper, the authors propose an autonomic navigation system (ANS) operating over vehicular ad-hoc networks (VANETs). The proposed ANS adopts a hierarchical algorithm to plan vehicle routes. The proposed ANS imitates the human nervous system when managing the navigation system, in which vehicles monitor traffic via VANETs. Moreover, this paper proposes a time-dependent routing algorithm that uses a novel traffic prediction method based on the routes of vehicles. This paper adopts EstiNet as simulator tool that dominates hundreds or thousands of VANET-based vehicles routing in two maps, Manhattan area, and Taipei city. The results show that the proposed ANS improves the average speed by 60.02 % when compared with the shortest path first (SPF) algorithm and by 15.49 % when compared with the distributed method of a traffic simulation in the Manhattan area. The proposed ANS also improves the average speed by 30.5 % when compared with the SPF algorithm and by 15.8 % when compared with the distributed method of a traffic simulation in the Taipei area. Furthermore, to emulate real environments, there is a scenario in which only a portion of the vehicles complies with the proposed ANS.     

Studies of Photon Correlation Spectroscopy of the Microemulsion of H2O/Tween 80/Benzene Derivative

The microemulsion of the H₂O/Tween 80/benzene derivative (C₆H₆, CH₃C₆H₅, NO₂C₆H₅ and NH₂C₆H₅) was investigated by the technique of Photon correlation spectroscopy. Autocorrelation data were measured at 90 scattering angle and were analyzed by using a quadratic fit and linear fit. The quadratic fit was found to describe all Properties better than the linear fit, and thus the linear fit was limited to the region of very short sampling time. When the amount of benzene derivative added to the sample solution was lower than V_max, the Z-average mean radius, <r>_z, and the polydispersit Y, μ2/Γ², increased as the amount of benzene derivative was increased. When the amount of benzene derivative was larger than V_max, the aqueous and organic phases separated and the <r> z, and μ₂/Γ² of all phases remained constant. Emulsification did not occur in the organic phase of the H₂O/Tween 80/aniline system. When we adjusted the Tween 80 concentration, it was found that <r>z and μ₂/Γ² decreased as the Tween 80 concentration increased.