Synthesis and Electronic Spectra of Some Monoazo Disperse Dyes Derived from N-Methylindoline

Several monoazo dyes suitable for transfer printing have been prepared from N-methylindoline and compared with the corresponding derivatives of N-methyl -12,3,4-tetrahy-droquinoline (kairoline). The presence of a five-membered terminal ring system leads to diminished π-interaction and results in modest hypsochromic and hypochromic shifts of the visible absorption band, relative to the analogous kairo-line derivatives, together with some deterioration in light-fastness properties on synthetic-polymer fibres.     

嵌入式存储器测试

随着存储器需求的增加以及制造技术的进步,嵌入式存储器在SOC系统中的地位越来越重要。与传统的分立存储器件测试相比,嵌入式存储器的测试呈现出新的挑战。本文试图全面叙述嵌入式存储器的各种结构,并介绍各种DFT（可测性设计）测试技术,如SCAN〔扫描〕、MBIST（存储器内建自测试）以及BISR（内建自修复）。     

Adaptive tuning piecewise cubic Hermite interpolation with Wiener filter in wavelet domain for scanning electron microscope images

Image processing is introduced to remove or reduce the noise and unwanted signal that deteriorate the quality of an image. Here, a single level two‐dimensional wavelet transform is applied to the image in order to obtain the wavelet transform sub‐band signal of an image. An estimation technique to predict the noise variance in an image is proposed, which is then fed into a Wiener filter to filter away the noise from the sub‐band of the image. The proposed filter is called adaptive tuning piecewise cubic Hermite interpolation with Wiener filter in the wavelet domain. The performance of this filter is compared with four existing filters: median filter, Gaussian smoothing filter, two level wavelet transform with Wiener filter and adaptive noise Wiener filter. Based on the results, the adaptive tuning piecewise cubic Hermite interpolation with Wiener filter in wavelet domain has better performance than the other four methods.     

Switchable dual-wavelength single-longitudinal-mode erbium-doped fiber laser using an inverse-Gaussian apodized fiber Bragg grating filter and a low-gain semiconductor optical amplifier

We present a stable and switchable dual-wavelength erbium-doped fiber laser. In the ring cavity, an inverse-Gaussian apodized fiber Bragg grating serves as an ultranarrow dual-wavelength passband filter, a semiconductor optical amplifier biased in the low-gain regime reduces the gain competition of the two wavelengths, and a feedback fiber loop acts as a mode filter to guarantee a stable single-longitudinal-mode operation. Two lasing lines with a wavelength separation of approximately 0.1 nm are obtained experimentally. A microwave signal at 12.51 GHz is demonstrated by beating the dual wavelengths at a photodetector.     

VISOR: Schema-based scene analysis with structured neural networks

A novel approach to object recognition and scene analysis based on neural network representation of visual schemas is described. Given an input scene, the VISOR system focuses attention successively at each component, and the schema representations cooperate and compete to match the inputs. The schema hierarchy is learned from examples through unsupervised adaptation and reinforcement learning. VISOR learns that some objects are more important than others in identifying the scene, and that the importance of spatial relations varies depending on the scene. As the inputs differ increasingly from the schemas, VISOR's recognition process is remarkably robust, and automatically generates a measure of confidence in the analysis.     

The self-esteem motive in social influence: agreement with valued majorities and disagreement with derogated minorities

We conducted three experiments to examine variables that might influence the longevity of socially induced food preferences in Norway rats. The duration of social influence on the food choices of 42-day-old rats (1) increased with both increasing numbers of demonstrators and increasing numbers of demonstrations by a single demonstrator, (2) varied with the temporal distribution of demonstrations, but (3) did not vary with the age of demonstrators. The results suggest that a single episode of social learning produces short-term, but not long-term, effects on a Norway rat's food choices. Copyright 1998 The Association for the Study of Animal Behaviour. Copyright 1998 The Association for the Study of Animal Behaviour.     

Power spectra of 6B4T and 3B2T codes

By means of a successive approximation approach, it is possible to calculate the power spectral density of unbounded block codes, 6B4T and 3B2T, using previously developed Line Code programs.     

An evaluation of the titanium sublimation pump

Experiments have been carried out to investigate the basic characteristics of the titanium sublimator vacuum pump. For this work an apparatus has been specially designed to enable the molecular ‘sticking coefficient’ to be measured over a range from in excess of 0.99 to below 0.01. Results show that for the chemically active gases such as oxygen and carbon monoxide virtually all molecules striking a clean film, stick on their first impact. This has been observed over the temperature range 77 to 373 K. Nitrogen and hydrogen show a more complex behaviour, their sticking characteristics being more dependent upon impurities in the film and also on the temperature of the substrate, both during film deposition and gas sorption.The use of a mass spectrometer for all pressure measurements has shown that the adsorption of the active gas causes considerable desorption of molecules already held on the film surface. Methane is a good example, this gas being desorbed by all the others investigated. In a comparison of published results it is suggested that some of the considerable disagreements can be explained by replacement. This is a process which cannot fully be taken into account in experiments where the measurements of the partial pressures of the gas components in the system are not made.     

Photonics True-Time-Delay Unit for Phased-Array Antenna Using Multiwavelength Fiber Laser Based on a Sagnac Interferemetric Filter

A photonics true-time-delay system for phased array beamforming using a chirped grating-based time-delay element and a novel multiwavelength erbium-doped fiber ring laser source employing a Sagnac filtering mirror is proposed. The Sagnac filtering mirror consists of a polarization maintaining directional coupler and two pieces of polarization maintaining fibers. The lasing wavelength and number are determined by properly adjusting the polarization controller within the unidirectional ring cavity and are very stable. A chirped-grating-based true-time-delay system using the proposed laser source is constructed and demonstrated experimentally.