Задача определения оценок сходства структур двух графов на основе выделения общих частей

Предложен алгоритм решения задачи определения оценок сходства структур, представленных обыкновенными графами, на основе выделения у них общих частей в виде изоморфных подграфов или частичных графов. Алгоритм работает в классе графов с одинаковыми векторами начальных описателей

A CMOS 0.8- µm transistor-only 1.63-MHz switched-current bandpass ΣΔ modulator for AM signal A/D conversion

This paper presents a CMOS 0.8-/spl mu/m switched-current (SI) fourth-order bandpass /spl Sigma//spl Delta/ modulator (BP-/spl Sigma//spl Delta/M) IC capable of handling signals up to 1.63 MHz with 105-bit resolution and 60-mW power consumption from a 5-V supply voltage. This modulator Is intended for direct A/D conversion of narrow-band signals within the commercial AM band, from 530 kHz to 1.6 MHz. Its architecture is obtained by applying a low-pass-to-bandpass transformation (z/sup -1//spl rarr/-z/sup -2/) to a 1-bit second-order low-pass /spl Sigma//spl Delta/ modulator (LP-/spl Sigma//spl Delta/M). The design of basic building blocks is based upon a detailed analysis of the influence of SI errors on the modulator performance, followed by design optimization. Memory-cell errors have been identified as the dominant ones. In order to attenuate these errors, fully differential regulated-folded cascode memory cells are employed. Measurements show a best SNR peak of 65 dB for signals of 10-kHz bandwidth and an intermediate frequency (IF) of 1.63 MHz. A correct noise-shaping filtering is achieved with a sampling frequency of up to 16 MHz.This work has been supported by the Spanish CICYT Project TIC 97-0580

Synthese und Organisation von Gold-Nanopartikeln mittels DNA

This work shows the synthesis and characterization of one-, two- and three-dimensional DNA-gold-nanoparticle hybridstructures, whereby DNA serves as a building block. The main part of this work focuses on structural characterizations, which are a big challenge to the available imaging and spectroscopic methods like atomic force, scanning electron and optical microscopy. The synthesis of one-dimensional assemblies was realized by the reduction of metal salt solutions at the backbone of DNA. Another strategy was the connection of pre-synthesized, cysteamine functionalized gold-nanoparticles along DNA strands, whereby the connection was done by using cis-platinum as linker. The resulting structures were characterized by TEM, SEM and AFM. While electron microscopy only allows to visualize the gold nanoparticles, AFM height and phase information was used to verify both DNA and particles. The two-dimensional structures, built up from immobilized and cross-linked gold-nanoparticles with DNA, were investigated by AFM and UV/Vis-spectroscopy. The attention was directed to the influence of the amount of crosslinking DNA and the resulting degree of aggregation, which led to two-dimensional assemblies. Here, a qualitative connection between structural and optical features was shown