Transition metal induced magnetism in smaller fullerenes (Cn for n≤36)

The magnetic properties of 3d transition metals (TM) encapsulated inside smaller fullerenes ranging from C20 to C36 have been investigated using spin polarized density functional theory. The TM impurities stabilize asymmetrically at an off-center position for n≥28. The total magnetic moment (MM) of TM@Cn complexes are largely contributed by TMs and a small amount of MM of 0.12-0.50 μB is induced on the cage carbon atoms. The 3d TM atoms interact with C atoms of C20 and C28 cage ferromagnetically (FM) except for Ni@C28 which shows antiferromagnetic (AFM) interaction. The magnetic interactions change from FM to AFM in C32 cage for Ti, V, Cr and Mn. The MM gets quenched in Ni@Cn for n≥32. The total MM of Mn@Cn does not show any change although the nature of magnetic interactions changes from FM to AFM at n=32. Ti and V are the only TMs which show positive cohesive energy in all fullerenes considered. The smallest fullerene which can encapsulate all 3d TM are Cn for n≥32, consistent with available experimental and theoretical results.     

Bending induced phase shifts in arbitrarily bent rectangular-coredual-mode waveguides

We examine the variation of the effective indexes of the two modes of an arbitrarily bent dual-mode rectangular-core waveguide. We find that under the large bending radius approximation, which is indeed the practical case for most of the devices, the waveguide bent with bending radius ρ in a plane at an angle &thetas; with the major axis is almost equivalent to bending it simultaneously in the plane of major and minor axes with bending radii ρsec&thetas; and ρcosec&thetas;, respectively. The bending-induced phase difference between the two modes is found (a) to be maximum when the waveguide is bent along the major axis, and (b) to decrease first and then increase in the opposite direction as the V-number is decreased. The results of our study can be used to improve the sensitivity of the dual-mode optical waveguide sensors and devices based on the bending of fiber     

Image and video processing using discrete fractional transforms

The mathematical transforms such as Fourier transform, wavelet transform and fractional Fourier transform have long been influential mathematical tools in information processing. These transforms process signal from time to frequency domain or in joint time–frequency domain. In this paper, with the aim to review a concise and self-reliant course, the discrete fractional transforms have been comprehensively and systematically treated from the signal processing point of view. Beginning from the definitions of fractional transforms, discrete fractional Fourier transforms, discrete fractional Cosine transforms and discrete fractional Hartley transforms, the paper discusses their applications in image and video compression and encryption. The significant features of discrete fractional transforms benefit from their extra degree of freedom that is provided by fractional orders. Comparison of performance states that discrete fractional Fourier transform is superior in compression, while discrete fractional cosine transform is better in encryption of image and video. Mean square error and peak signal-to-noise ratio with optimum fractional order are considered quality check parameters in image and video.     

Water-Soluble Carbon Nanotubes from Bitumen Waste: Synthesis, Functionalisation and Derivatisation for its Use as Superabsorbent

A simple method for the preparation of carbon nanotubes (CNTs) from bitumen waste and their derivatisation with polyacrylamide was achieved. Synthesised CNTs were functionalised in the presence of dilute nitric acid followed by derivatisation with polyacrylamide using the mixture of potassium persulphate-ferrous ammonium sulphate as a redox initiator and N,N′-methylene-bis-acrylamide as a crosslinking agent. The functionalisation and derivatisation of the CNTs were confirmed through Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and X-ray diffraction techniques. The effect of derivatisation on the thermal properties of the CNTs was studied by thermogravimetric analysis, differential thermogravimetric analysis and differential thermal analysis. The crosslinked derivatised product, CNT-cl-poly(AAm), was thermally more stable than the functionalised CNTs. The water-absorption capacity of the derivatised CNTs was investigated in deionised water as a function of time, temperature and pH of the swelling medium. CNT-cl-poly(AAm) was found to be an efficient water-absorption device with the maximum absorption capacity of 476 %.     

在SoC设计中用SystemC虚拟平台预览USB的性能

现在的程序员和系统架构师有比以往更多的软件可用于SoC(单片系统)设计,但也面临着一个日益困扰他们的问题：如何在设计前期,在硅片拿到手以前评估和优化软件的性能。为解决这个问题,程序员们转向虚拟平台,这种平台采用软件来对目标硬件的架构和功能建模。     

Dirty-paper coding versus TDMA for MIMO Broadcast channels

We compare the capacity of dirty-paper coding (DPC) to that of time-division multiple access (TDMA) for a multiple-antenna (multiple-input multiple-output (MIMO)) Gaussian broadcast channel (BC). We find that the sum-rate capacity (achievable using DPC) of the multiple-antenna BC is at most min(M,K) times the largest single-user capacity (i.e., the TDMA sum-rate) in the system, where M is the number of transmit antennas and K is the number of receivers. This result is independent of the number of receive antennas and the channel gain matrix, and is valid at all signal-to-noise ratios (SNRs). We investigate the tightness of this bound in a time-varying channel (assuming perfect channel knowledge at receivers and transmitters) where the channel experiences uncorrelated Rayleigh fading and in some situations we find that the dirty paper gain is upper-bounded by the ratio of transmit-to-receive antennas. We also show that min(M,K) upper-bounds the sum-rate gain of successive decoding over TDMA for the uplink channel, where M is the number of receive antennas at the base station and K is the number of transmitters.     

DRYING OF SOY PULP (OKARA) IN A BED OF INERT PARTICLES

Drying of okara, an insoluble pulp residue waste byproduct of tofu production, was investigated in a continuously moving bed of inert particles subjected to vortex-like motion. The experimental variables in their respective ranges included the mass of Teflon pellets used as inert particles (0.4-1.2 kg), feed rate (0.5-1.4 kg/h), inlet air temperature (100-145°C) and airflow rate (195-271 m³/h). The dryer showed good performance in general and produced dry okara with moisture content ranging from 5 to 33% wb depending upon the operating conditions. The product recovery ranged from 80 to 90% on dry basis in most experiments. The specific water evaporation rate in okara drying increased with increasing of the feed rate and mass of Teflon pellets. However, the specific heat consumption decreased with an increase in the okara feed rate. Results showed that specific heat consumption for okara drying in a bed of inert particles was about 3 to 4 times higher in comparison with that of free water.     

Phenotypic analysis of resident lymphoid cells in the conjunctiva and adnexal tissues of rat

The conjunctival associated lymphoid tissue is considered to be an integral part of the mucosal immune system. Under normal circumstances immune mechanisms in mucosal associated lymphoid tissue of the gut and bronchus can selectively suppress, rather than enhance, immune responsiveness to encountered antigens, inducing a state of tolerance. It is possible that conjunctival associated lymphoid tissue can also induce a state of tolerance to encountered antigens. Such a response may be exploited to modulate immune mediated ocular disease. Enhanced tolerance may protect the host against foreign antigen. Alternatively, under certain circumstances when the normal immune system is altered or disrupted the mucosal tissue may act to induce sensitisation and trigger immune mediated disease. The rat is frequently used as an animal model of immune mediated eye disease, but the normal profile of immune cells in the rat conjunctiva has not been studied. This information is essential for meaningful interpretation in the experimental situation. In this study we examined the immunophenotype of lymphoid tissue associated with the conjunctiva, lacrimal gland and Harderian gland of the Lewis rat. CD4+, Ia+ and the monocyte/macrophage population of cells were found predominantly in the substantia propria of the conjuctiva and interstitial connective tissue of the glands. CD8+ cells were distributed mainly in relation to the conjunctival and glandular epithelium. Goblet cells stained strongly with the monoclonal antibody (MAb) MRC OX-39, which is a marker for IL-2 receptors. The overall pattern of distribution of immunocompetent cells in the rat was found to be similar to that reported in humans.