Decentralized state-feedback chaotification method of discrete Takagi-Sugeno fuzzy systems

A new chaotification method is proposed for making an arbitrarily given discrete Takagi-Sugeno (TS) fuzzy system chaotic. Based on a given discrete TS fuzzy system, the new chaotification method uses the decentralized state-feedback control and the continuous sawtooth function, instead of the modulo operation, to construct a chaotic nonlinear system,which can generate discrete chaos with the arbitrarily desired amplitude bound. We apply the improved Marotto theorem to mathematically prove that the controlled system is chaotic in the sense of Li and Yorke. In particular, an explicit formula for the computation of chaotification parameters is obtained. A numerical example is used to illustrate the theoretical results.     

Design of a sector bowtie nano-rectenna for optical power and infrared detection

We designed a sector bowtie nanoantenna integrated with a rectifier (Au−TiO_x−Ti diode) for collecting infrared energy. The optical performance of the metallic bowtie nanoantenna was numerically investigated at infrared frequencies (5−30 μm) using three-dimensional frequency-domain electromagnetic field calculation software based on the finite element method. The simulation results indicate that the resonance wavelength and local field enhancement are greatly affected by the shape and size of the bowtie nanoantenna, as well as the relative permittivity and conductivity of the dielectric layer. The output current of the rectified nano-rectenna is substantially at nanoampere magnitude with an electric field intensity of 1 V/m. Moreover, the power conversion efficiency for devices with three different substrates illustrates that a substrate with a larger refractive index yields a higher efficiency and longer infrared response wavelength. Consequently, the optimized structure can provide theoretical support for the design of novel optical rectennas and fabrication of optoelectronic devices.     

A Comparative ESR Study on Blood and Tissue Nitric Oxide Concentration during Renal Ischemia-Reperfusion Injury

Electron paramagnetic resonance (EPR) spin trapping technology is a sensitive and unambiguous method for detection of nitric oxide (NO). Due to the short lifetime, NO must be trapped before EPR measurement. There are two EPR spin trapping techniques used currently, including the detections of EPR signals of diethyldithiocarbamate-iron-nitric oxide (DETC₂-Fe²⁺-NO) and nitrosyl hemoglobin (HbNO). In this study, we firstly investigated the kinetics of the EPR signal of DETC₂-Fe²⁺-NO in normal and ischemia-reperfused kidneys. In normal rat kidneys, the signal of DETC₂-Fe²⁺-NO was found at 5 min after the spin trappers Fe²⁺/DETC were administrated, the peak concentration was at 15 min and the period with relatively stable signal intensity was at the time range from 15 to 70 min. In the ischemia-reperfused rat kidneys, the signal of DETC₂-Fe²⁺-NO was increased at 30 min of ischemia and decreased at 60 min of ischemia after the occlusion of renal artery (corresponding to the time course of 60 and 90 min after Fe²⁺/DETC injection respectively). We then investigated the EPR signal of HbNO in blood. No characteristic HbNO signal was found in the rats of the sham control and 30 min of ischemia. An HbNO signal occurred in the rats exposed to 60 min of ischemia and it became pronounced with increased duration of reperfusion. The signal intensity reached a plateau at 150 min of reperfusion. The results suggest that the DETC₂-Fe²⁺-NO signal can be only suitable for the NO measurement in the short-term ischemia-reperfusion model, whereas the HbNO signal can be applied to represent NO in the relatively long-term ischemia-reperfusion model. In addition, N^G-nitro-L-arginine (L-NAME) and allopurinol were used to identify the source of NO. By detecting the HbNO signal, we demonstrated that the activation of xanthine oxidase is an important source of NO formation at the long-term period of ischemia and reperfusion. Authors' address: Jiangang Shen, School of Chinese Medicine, University of Hong Kong, 10 Sassoon Road, Hong Kong SAR, China     

基于折反射原理的层去反求技术研究

为了克服传统层去反求测量中图像衬比度较低的缺陷,提出一种新的基于棱镜反射原理的层去反求图像摄取方法。该方法利用棱镜的全发射和折射作用提高图像衬比度,根据物体反射率的高低可分别采用垂直照明和倾斜照明,分别可获得高衬比度的亮目标暗背景和暗目标亮背景图像,为了校正由于折反射引入的几何变形,推出了相应的数学变换模型。该研究已成功投入实际产品校正的应用中,研究表明这种新的层去法比起传统的层去法不仅在于图像衬比度高,而且物体截面图像的轮廓更清晰可靠、无需填充反差材料,有望在零件及模型的反求测量中发挥较大的作用。     

The solid–liquid interface energy of organic crystals

A simple thermodynamic model, originally developed for metals based on the Gibbs–Thomson equation and related considerations for homogeneous nucleation, has been extended to predict the solid–liquid interface energy γ_sl of organic crystals. The model predictions correspond to available experimental and other theoretical results for 38 organic crystals. Copyright © 2007 John Wiley & Sons, Ltd.     

Initiation of petroleum formation and antioxidant function – a DFT study of sulfur?sulfur bond dissociation enthalpies

Experimental studies showed that sulfur radicals play the vital role in petroleum formation. 1 Sulfur‐ centered radicals also exhibit activities in antioxidant functions. Here we conduct a theoretical investigation of their precursor‐disulfides. By investigation into substituent effect on sulfur? sulfur bond dissociation enthalpies (S? S BDEs), we would like to find the most effective provider for sulfur radicals. In the present work, 50 alpha‐substituted disulfides and 16 para‐substituted aryl disulfides are studied systematically, with the general formula XS‐SX or HS‐SX. The substituent effect on S? S BDEs is found to be very eminent, ranging from 33.2 to 75.0 kcal/mol for alpha‐substituted disulfide, and from 43.7 to 59.7 kcal/mol for para‐substituted phenyl disulfides. We also evaluate the performance of 44 density functional methods to get an accurate prediction. A further study indicates that substituents play a major role in radical energies, instead of molecule energies, which is substantiated by the good linearity between XS‐SX bond dissociation enthalpy (BDE) and HS‐SX BDE. Copyright © 2007 John Wiley & Sons, Ltd.     

A Surface Mounting Embedded Optical Transceiver with Bi-Directional Data Rate of Eight Channels × 10 Gbps

Abstract

The bi-directional data rate is investigated of an eight-channel × 10-Gbps optical transceiver with a size of 15 mm × 15 mm × 6 mm and ball grid array package form that was designed and fabricated. A passive optical coupling method is designed based on a coupling lens array, which is transformed to substrate through a carrier. This electrical performance is characterized through a 3D full wave simulation and shows great advantages compared with traditional pluggable optical transceivers. Experimental eye diagram measurement in loop-back mode via a 2-m-long multi-mode fiber array shows an eye width of 51.984 ps at a bit-error rate order of 10^?12, which proves the transceiver's ability for 10.3125-Gbps data transmission.     

Forward and inverse problem for cardiac magnetic field and electric potential using two boundary element methods

This paper discusses the forward and inverse problem for cardiac magnetic fields and electric potentials.A torso-heart model established by boundary element method(BEM) is used for studying the distributions of cardiac magnetic fields and electric potentials.Because node-to-node and triangle-to-triangle BEM can lead to discrepant field distributions,their properties and influences are compared.Then based on constructed torso-heart model and supposed current source functional model-current dipole array,the magnetic and electric imaging by optimal constrained linear inverse method are applied at the same time.Through figure and reconstructing parameter comparison,though the magnetic current dipole array imaging possesses better reconstructing effect,however node-to-node BEM and triangleto-triangle BEM make little difference to magnetic and electric imaging.     

Theoretical Study on a Cluster-Seven-Core Photonic Crystal Fiber with High Nonlinearity and High-Power Endurance

We present a novel cluster-seven-core photonic crystal fiber which possesses high nonlinearity and supports the high-power pumping. Its nonlinearity coefficient and effective mode area are calculated by the full vector multipole method. Compared with the single core PCF, the cluster-seven-core photonic crystal fiber can support high-power beam transmitting in the core, and simultaneously has high nonlinearity. This kind of photonic crystal fiber can be applied to the photoelectron-device field.     

Coexistence of magnetism and superconductivity in the hole doped FeAs-based superconducting compound

The magnetic and superconducting properties of the Sm-doped FeAs-based superconducting compound were investigated under wide ranges of temperature and magnetic field. After the systematical magnetic ion substitution, the superconducting transition temperature decreases with increasing magnetic moment. The hysteresis loop of the La_0.87?xSm_xSr_0.13FeAsO sample shows a superconducting hysteresis and a paramagnetic background signal. The paramagnetic signal is mainly attributed to the Sm moments. The experiment demonstrates that the coexistence of magnetism and superconductivity in the hole doped FeAs-based superconducting compounds is possible. Unlike the electron doped FeAs-based superconducting compounds SmFeAsOF, the hole doped superconductivity is degraded by the substitution of La by Sm. The hole-doped and electron-doped sides are not symmetric.