Waveguide microcavity based on photonic microstructures

A waveguide based microcavity exhibiting a quality factor Q/spl ap/2500 has been realized by incorporating a /spl lambda//4 phase shift into a 1-D photonic microstructure. The microstructure has an overall length of 3 /spl mu/m, consists of a deeply etched grating with very narrow (75 nm) air-gaps and exhibits a third-order stop band in the 800-900 nm wavelength regime. A comparison between measurement and simulation suggests that there is a thin (approximately 18 nm) skin of oxidized material at the etched semiconductor-air interfaces.     

A location‐aware peer‐to‐peer overlay network

This work describes a novel location‐aware, self‐organizing, fault‐tolerant peer‐to‐peer (P2P) overlay network, referred to as Laptop. Network locality‐aware considerations are a very important metric for designing a P2P overlay network. Several network proximity schemes have been proposed to enhance the routing efficiency of existing DHT‐based overlay networks. However, these schemes have some drawbacks such as high overlay network and routing table maintenance overhead, or not being completely self‐organizing. As a result, they may result in poor scalability as the number of nodes in the system grows. Laptop constructs a location‐aware overlay network without pre‐determined landmarks and adopts a routing cache scheme to avoid maintaining the routing table periodically. In addition, Laptop significantly reduces the overlay maintenance overhead by making each node maintain only the connectivity between parent and itself. Mathematical analysis and simulations are conducted to evaluate the efficiency, scalability, and robustness of Laptop. Our mathematical analysis shows that the routing path length is bounded by log_d N, and the joining and leaving overhead is bounded by d log_d N, where N is the number of nodes in the system, and d is the maximum degree of each node on the overlay tree. Our simulation results show that the average latency stretch is 1.6 and the average routing path length is only about three in 10 000 Laptop nodes, and the maximum degree of a node is bounded by 32. Copyright © 2006 John Wiley & Sons, Ltd.     

Bright Aggregation‐Induced Emission Dots for Dynamic Tracking and Grading of Patient‐Derived Xenografts in Zebrafish

Cancer prognosis will benefit from a scoring system that could grade malignant traits of patient‐derived cells by assessing their growth and metastasis in a living system. Specific tracking of patient‐derived cells requires labeling by contrast agents with good signal‐to‐noise ratio and no specific stain of host tissues. Towards this aim, aggregation‐induced emission (AIE) dots are developed for in vivo cancer tracking with emphasis on reproducible optimized formulation and specific fluorescent labeling of cells that enable enhanced spatial temporal resolution in vivo. The importance of energy‐dependent AIE dots uptake for patient‐derived cell labeling is emphasized to reveal their specific uptake by viable cancer cells. Using optically transparent zebrafish embryo, the ability is demonstrated to follow the engraftment of transplanted AIE dot labeled cells in zebrafish brains over one week. Cells detected outside the brain after 7 d are quantified as metastatic cells. Results from seven clinical samples demonstrate the utility of this methodology to differentiate low engraftment level of benign neoplasms from higher engraftment level and metastasis detected in malignant ovarian cancer specimens. Achieving clinically validated results supports the use of AIE dot labeled patient derived cells in zebrafish xenografts for future cancer prognosis.     

Modeling of program, erase and retention characteristics of charge-trap gate all around memories

This paper describes the effect of geometry in charge-trap (CT) memory devices. We first theoretically analyze the impact of the curvature radius on the behavior of the gate current in Gate-All-Around devices, and then describe the change to make to planar model in order to fit the cylindrical devices characteristics. This model is used to simulate Nanocrystal and SONOS program, erase and retention behaviors. The dynamics enhancement during program/erase due to the bending of the active region in such cylindrical devices is explained. The scaling perspectives conclude this paper.     

Phase formation and texture of nickel silicides on Si1−xCx epilayers

We investigated the phase formation and texture of nickel silicides formed during the reaction of 10 nm sputter deposited nickel with Si_1−xC_x epitaxial layers on Si(1 0 0) substrates, having a carbon content between 0 and 2.5 atomic percent. It was found that both the formation temperature as well as the texture of the metal-rich phases is influenced by the amount of carbon in the Si_1−xC_x layer. To determine the influence of the location of the carbon during the silicidation process we also investigated the reaction of 10 nm nickel on Si(1 0 0) substrates, where carbon was either alloyed in the nickel layer or deposited as an interlayer at the interface between the nickel and the substrate. Depending on the location of the carbon, a different thermal stability of the layer was found.     

Modeling and control of expressiveness in music performance

Expression is an important aspect of music performance. It is the added value of a performance and is part of the reason that music is interesting to listen to and sounds alive. Understanding and modeling expressive content communication is important for many engineering applications in information technology. For example, in multimedia products, textual information is enriched by means of graphical and audio objects. In this paper, we present an original approach to modify the expressive content of a performance in a gradual way, both at the symbolic and signal levels. To this purpose, we discuss a model that applies a smooth morphing among performances with different expressive content, adapting the audio expressive character to the user's desires. Morphing can be realized with a wide range of graduality (from abrupt to very smooth), allowing adaptation of the system to different situations. The sound rendering is obtained by interfacing the expressiveness model with a dedicated postprocessing environment, which allows for the transformation of the event cues. The processing is based on the organized control of basic audio effects. Among the basic effects used, an original method for the spectral processing of audio is introduced.     

用DSP Builder设计基于PLD的数字信号处理器

不断发展的DSP技术迅速地拓宽扩展到了各应用领域,但传统的DSP处理器由于以顺序方式工作而数据处理速度较低,且在功能重构及应用目标的修改方面缺乏灵活性。本文介绍一种崭新的基于Matlab与QuartusⅡ的DSP处理器的设计软件DSP Builder,详细介绍了其设计流程与优点,并以DDS直接数字合成器的实现为例说明用该软件来设计DSP处理器的方法以及与Matlab、QuartusI之间的关系。     

A new iterative diakoptics-based multilevel moments method forplanar circuits

This paper combines a multilevel moments method (MMM) scheme with a modified diakoptics (MD) technique and a block Gauss-Seidel (BGS) iterative technique to reduce the solution time of large planar microwave structures. The proposed MMM scheme has two levels. On the lower level, the planar circuit is divided into several subcircuits using two types of artificial ports. At the higher level, general basis functions defined over the complete circuit are generated in an iterative way. The validity and the efficiency of the new technique are validated by several examples, including a large low-pass filter     

Cycle-slip analysis of the Mth-power NDA feedforward carriersynchronizer for MPSK

We analyze the cycle-slipping behavior of the Mth-power nondecision-aided (NDA) feedforward carrier synchronizer for M-ary phase-shift keying (MPSK). The averaging filter is a block window accumulator, and postprocessing is used to eliminate equivocation. An asymptotic (high E_s/N_o) expression for the cycle-slip probability is derived and verified by computer simulation. A “hybrid” approach, combining analytical results with importance sampling simulation techniques, allows for the fast and accurate determination of the cycle-slip probability for all E_s /N_o values of practical interest