解决高清音频IC设计难题

视频流和图像绘制技术的进步,极大地提高了高清（HD）运动图像的质量。加上家庭娱乐中心逐渐流行,这些因素已成为追求＂家庭影院＂体验以及便携式电子设备发展的重要推动力。除了高清视频之外,高清音频（HD Audio）也随之引入,     

Ordered carbon nanotubes for optical power limiting devices

The electrospinning (ES) process was used to fabricate composite nanofibers (NFs) of poly(methyl methacrylate), PMMA, with embedded multiwalled carbon nanotubes (MWNTs) from a solution of PMMA in N,N-dimethylformamide (DMF) with homogenously dispersed MWNTs. Using both the sinklike and the elongation flows in the electrospinning process, we aligned the carbon nanotubes (CNTs) along the fiber axis. The NFs were subsequently deposited in an aligned manner on a glass surface using the electrostatic lens created by the edge of a rotating wheel collector. Semitransparent optical power limiter (OPL) films (~50% transmittance) were fabricated using an optically compatible polymeric resin infiltrated into the collected NFs. These comprised oriented NFs with different carbon nanotube loadings and film thicknesses. The OPLs exhibited high limiting abilities, with a limiting threshold of 1.5 J/cm(2) at about 50% linear transmittance. Some degree of polarization was also achieved, but significantly lower than expected because of the NF orientation.     

Three-dimensional traction forces of Schwann cells on compliant substrates

The mechanical interaction between Schwann cells (SCs) and their microenvironment is crucial for the development, maintenance and repair of the peripheral nervous system. In this paper, we present a detailed investigation on the mechanosensitivity of SCs across a physiologically relevant substrate stiffness range. Contrary to many other cell types, we find that the SC spreading area and cytoskeletal actin architecture were relatively insensitive to substrate stiffness with pronounced stress fibre formation across all moduli tested (0.24–4.80 kPa). Consistent with the presence of stress fibres, we found that SCs generated large surface tractions on stiff substrates and large, finite material deformations on soft substrates. When quantifying the three-dimensional characteristics of the SC traction profiles, we observed a significant contribution from the out-of-plane traction component, locally giving rise to rotational moments similar to those observed in mesenchymal embryonic fibroblasts. Taken together, these measurements provide the first set of quantitative biophysical metrics of how SCs interact with their physical microenvironment, which are anticipated to aid in the development of tissue engineering scaffolds designed to promote functional integration of SCs into post-injury in vivo environments.     

Function-based assembly: an application of MEMS-based assembly of rate gyroscopes

The assembly of MEMS-based devices in certain applications requires alignment within tolerances better than ±1μm. This standard has proven to be difficult to achieve consistently due to manufacturing and assembly errors. This article describes an active alignment process which incorporates the actual geometric parameters of the microelements as well as geometric constraints in order to determine the optimal location of the microelements in the assembly. The determination of this location guarantees optimal functionality of the device and helps achieve tight alignment tolerances without compromising the device design. The effectiveness of this approach is demonstrated in a micromachined vibrating rate gyroscope assembly. Simulation and measurements taken of the assembled rate gyroscope confirmed an assembly accuracy of better than ±1μm.     

Patterns of eye movements during parallel and serial visual search tasks.

In 2 experiments with a total of 24 undergraduates, eye movements were monitored while Ss performed parallel and serial search tasks. In Exp 1a, Ss searched for an "O" among "X"s (parallel condition) and for a "T" among "L"s (serial condition). In the parallel condition of Exp 1b, "Q" was the target and "O"s were distractors; in the serial condition, these stimuli switched roles. Displays contained 1, 12, or 24 stimuli, with both target-present and target-absent trials. RT and eye-movement measures (number of fixations, saccadic error, and latency to move) indicated that search efficiency was greatest in the parallel conditions, followed by the serial condition of Exp 1a and, finally, by the serial condition of Exp 1b. This suggests that eye movements are correlated with the attentional processes underlying visual search. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Analysis of the geometrical features detectability constraints for laser-scanner sensor planning

This paper presents a planning approach for automatic synthesis of the viewpoint locations of a laser scanner that satisfy the detectability constraints of the geometrical features of a given object. Dominant constraints taken into consideration were the laser scanner field of view, depth of view, and the maximum permissible view angle. The approach is task driven and sensor model based. Information is given about the scanned object and its selected features, as well as about the optical characteristics of the sensor. Planning is presented as an optimisation problem where the optimal laser-scanner viewpoint must satisfy all the constraints simultaneously. The approach is demonstrated by scanning a 2D feature, and through planning an experiment in which robotic assembly of a car door is assisted by a laser scanner.     

A time-dependent Mueller-like formulation for the study of the RF spectrum and time-resolved polarization phenomena in birefringent systems

Using a novel 4/spl times/4 Mueller-like time-dependent matrix to describe the propagation of modulated light in birefringent optical systems, a new method for characterizing the polarization dependence of the RF spectrum in systems having polarization-mode dispersion and polarization-dependent loss is proposed and demonstrated. By measuring the RF spectra for nine different input states of polarization (SOP), the spectrum of any other input SOP is accurately predicted. Another application of the general formulation allows the study of the dependence of the time-resolved characteristics of the SOP of light propagating in a birefringent medium.     

Decision making and personality in traffic offenders: a study of Israeli drivers

Traffic offences present danger to the offender, and to others. This study examines differences in decision making and personality between traffic offenders and non-offenders. Fifty-one traffic offenders participating in penalty courses were compared to a control group of 36 drivers who were not penalized for traffic offences in the 5 years prior to the study. All participants performed the Iowa Gambling Task (IGT), a popular decision task employed for assessing cognitive impulsivity, and completed the "big five" personality questionnaire. The results showed that traffic offenders made fewer advantageous choices on the IGT; and an analysis with a formal cognitive model, the Expectancy Valance model, suggests that this results from offenders' high weighting of gains compared to losses. An examination of personality factors reveals that traffic offenders were more extraverted. The predictive power of IGT performance was comparable to that of the personality factor. These results demonstrate that the IGT can be useful for studying individual differences in risk taking in a real-world task, and combined with the EV model, identify the sources of these differences.     

Detection of gaseous plumes in IR hyperspectral images using hierarchical clustering

The emergence of IR hyperspectral sensors in recent years enables their use in remote environmental monitoring of gaseous plumes. IR hyperspectral imaging combines the unique advantages of traditional remote sensing methods such as multispectral imagery and nonimaging Fourier transform infrared spectroscopy, while eliminating their drawbacks. The most significant improvement introduced by hyperspectral technology is the capability of standoff detection and discrimination of effluent gaseous plumes without need for a clear reference background or any other temporal information. We introduce a novel approach for detection and discrimination of gaseous plumes in IR hyperspectral imagery using a divisive hierarchical clustering algorithm. The utility of the suggested detection algorithm is demonstrated on IR hyperspectral images of the release of two atmospheric tracers. The application of the proposed detection method on the experimental data has yielded a correct identification of all the releases without any false alarms. These encouraging results show that the presented approach can be used as a basis for a complete identification algorithm for gaseous pollutants in IR hyperspectral imagery without the need for a clear background.