Proximate Composition and Seed Lipid Components of Sorghum Cultivars from Argentina

Seeds of 11 sorghum cultivars ( Sorghum bicolor ) from Argentina were analysed for proximate composition, fatty acids and sterols. Oil, protein, carbohydrate and ash contents varied between 41 and 66 g kg⁻¹, 111 and 156 g kg⁻¹, 670 and 730 g kg⁻¹ and 13·8 and 20·6 g kg⁻¹ of dry matter, respectively. Fatty acid profiles revealed that the major acids were palmitic (15·1–24·8%), oleic (29·9–41·8%) and linoleic (35·9–51·3%). Unsaponifiable matter was examined for sterols. Sitosterol was the prominent component in all cultivars (43·8–57·9%), followed by campesterol (18·7–29·1%) and stigmasterol (12·4–20·5%).     

Comparative characterization of chip to epoxy interfaces by molecular modeling and contact angle determination

An investigation of interfacial interaction has been performed between three epoxy molding compound materials and a native silicon dioxide layer (SiO₂) usually found at chip surfaces. The epoxy materials were an industry oriented epoxy molding compound Epoxy Phenol Novolac (EPN), its filled variety EPN^F (with silica particles) and a model aromatic epoxy¹ (2 1 2). All systems are described in full in [1] and [2]. The free surfaces of the solid materials were experimentally analyzed by contact angle measurements of three different liquids (water, methylene-iodide (MI) and glycerol). Results are compared to interfacial energies obtained by analysis of the interfaces in bimaterial molecular models, yielding reasonable agreement. A qualitative prediction regarding the influence of water on the interfacial strength between chip and molding compound is attempted.     

Cathodoluminescence studies of C<Subscript>60</Subscript> fullerene-based films and nanostructures

The objects of investigation in this work are submicron Cm fullerene-based films and fullerene nanostructures fabricated by electron-beam lithography. The set of techniques for studying the fullerenes is extended due to attraction of the spectral cathodoluminescence (CL) to either of the initial fullerene films or submicron net structures with period of about 0.9 μm, wall height 0.6 μm, and width about 0.4 μm. The maxima of the CL spectra of the initial C₆₀ films are in good agreement with the energy-band structure of the amorphous fullerene film. In turn, the CL spectrum of the fullerene net structures possesses both peculiarities of the fullerene energy-band structure and it clearly exhibits the oscillations of the spectrum with a period as large as 0.08 eV. Such periodical fullerence net structures possess the properties of an optical resonator on the system “fullerene net (n = 2.3)-air (n = 1).” The text was submitted by the authors in English.     

A layer radiowave absorber based on double-period lattices of resistive squares

A radiowave-absorbing composite material based on double-period lattices of resistive squares is considered. Methods of the electric circuit and long line theories are applied to obtain expressions for the estimate of the effective permittivity of such a composite. It is shown that the frequency dependence of the effective permittivity of the realized composite is close to the relaxation value. The reflection characteristics of a radiowave absorber based on a composite with double-period lattices of resistive squares are investigated. It is found that, for such a radiowave absorber, the ratio of the difference of the extreme wavelengths of its operating band (corresponding to the minus-10-dB reflection level) to the thickness of the radiowave absorber is within an interval of 4.2–4.5.     

Improving hydrogenation efficiency of polycrystalline silicon thin film transistors by a new approach

In this paper, a new hydrogenation process of poly-Si thin film for the fabrication of poly-Si thin film transistors (TFTs) is proposed. In the new approach, the hydrogenation of TFTs is performed before deposition of contact metal. N-channel and p-channel poly-Si TFTs with various channel lengths and widths were fabricated with the new and conventional processes for comparison. The results verified that the efficiency of hydrogenation has been improved remarkably by the new process. The field-effect mobility of carriers, the on state current, threshold voltage and the on/off states current ratio have been greatly improved, and the trap state density has been reduced significantly.     

Appropriate micro-lens to improve coupling between laser diodes and singlemode fibres

A new configuration of micro-lensed fibre that consists of a quarter pitch length of 125/125 /spl mu/m graded index section with a hyperbolic end shape is proposed. Low loss and long working distance for laser diode and singlemode fibre coupling have been verified.     

Continuous-time feedforward SD modulators with robust lowpass STF

Continuous-time sigma-delta modulators are often implemented using the feedforward structure. This type of architecture is prone to large out-of-band peaking and degraded anti-aliasing filtering owing to its sensitivity to process variation. Two alternative continuous-time delta- sigma modulators, which exhibit significantly lower signal transfer function (STF) sensitivity, are described.     

Visualization of Back Pain Data—A 3-D Solution

Traditional approaches to gathering and visualizing pain data rely on two-dimensional (2-D) human body models, where different types of sensation are recorded with various monochrome symbols. We propose an alternative that uses a three-dimensional (3-D) representation of the human body, which can be marked in color to visualize and record pain data.     

Fundamentals of Fast Simulation Algorithms for RF Circuits

Designers of RF circuits such as power amplifiers, mixers, and filters make extensive use of simulation tools which perform periodic steady-state analysis and its extensions, but until the mid 1990s, the computational costs of these simulation tools restricted designers from simulating the behavior of complete RF subsystems. The introduction of fast matrix-implicit iterative algorithms completely changed this situation, and extensions of these fast methods are providing tools which can perform periodic, quasi-periodic, and periodic noise analysis of circuits with thousands of devices. Even though there are a number of research groups continuing to develop extensions of matrix-implicit methods, there is still no compact characterization which introduces the novice researcher to the fundamental issues. In this paper, we examine the basic periodic steady-state problem and provide both examples and linear algebra abstractions to demonstrate connections between seemingly dissimilar methods and to try to provide a more general framework for fast methods than the standard time-versus-frequency domain characterization of finite-difference, basis-collocation, and shooting methods     

Piecewise-Linear Identification of Nonlinear Dynamical Systems in View of Their Circuit Implementations

We address here an aspect of the problem concerning circuit implementations of nonlinear dynamical systems that depend on control parameters. In particular, the problem of the identification of such systems is addressed in two steps. The first step uses the state-space reconstruction (through time delay reconstruction associated with principal component analysis) on the basis of scalar time series measured in the systems to be identified. The second step deals with the approximation of the flow in the reconstructed space (through a piecewise-linear approximation technique). The proposed method is first validated with two examples concerning known systems and then applied successfully to two realistic cases.