Formal design verification of digital circuitry

This paper examines a methodology for hardware verification developed by RSRE (Royal Signals and Radar Establishment) in the context of the SRI International's EHDM (Enhanced Hierarchical Design methodology) specification/verification system. The methodology utilizes a four-level specification hierarchy with the following levels: functional level, finite automata model, block model, and circuit level. The properties of a level are proved as theorems in the level below it. In this paper, this methodology is applied to a N-bit counter/multiplexer circuit and is critically examined. The specifications are written in EHDM's specification language, Extended Special, and the proofs are performed using the EHDM theorem prover. Recommendations are made for improving both the RSRE methodology and the EHDM system.     

Automated fluorometric method for determination of citric acid in sewage and sewage effluents

An automated method for the determination of citric acid in sewage and sewage effluents is described. The method is based on Furth-Herman reaction by which citric acid is first converted to citraconic anhydride and then condensed with pyridine to form a fluorescent product.The above reaction has been automated to allow the analysis of 10 samples h⁻¹ down to 10 μg 1, without any separation or preconcentration.     

The effect of neutron irradiation on the internal friction of copper

Measurements of internal friction at 1 Hz have been made on copper during continuous fast neutron irradiation at temperatures of 300, 378 and 500 K. Irradiation produced an initial increase followed by a decrease of the damping to a value below the pre-irradiation value. The decay of the damping which was interpreted in terms of the Granato-Lücke theory of strain amplitude-independent damping, was considered to be due to the decreased nobility of the dislocations through pinning by the irradiation produced point defects. Activation energies for diffusion of the defect to and along the dislocation was determined to be 0.58 and 0.38 eV respectively.     

Study on Sequential Feeding Networks for Subarrays of Circularly Polarized Elliptical Dielectric Resonator Antenna

Circularly polarized (CP) dielectric resonator antenna (DRA) subarrays have been numerically studied and experimentally verified. Elliptical CP DRA is used as the antenna element, which is excited by either a narrow slot or a probe. The elements are arranged in a 2 by 2 subarray configuration and are excited sequentially. In order to optimize the CP bandwidth, wideband feeding networks have been designed. Three different types of feeding network are studied; they are parallel feeding network, series feeding network and hybrid ring feeding network. For the CP DRA subarray with hybrid ring feeding network, the impedance matching bandwidth (S₁₁<-10 dB) and 3-dB AR bandwidth achieved are 44% and 26% respectively     

Robust 3-D modeling of vasculature imagery using superellipsoids

This paper presents methods to model complex vasculature in three-dimensional (3-D) images using cylindroidal superellipsoids, along with robust estimation and detection algorithms for automated image analysis. This model offers an explicit, low-order parameterization, enabling joint estimation of boundary, centerlines, and local pose. It provides a geometric framework for directed vessel traversal, and extraction of topological information like branch point locations and connectivity. M-estimators provide robust region-based statistics that are used to drive the superellipsoid toward a vessel boundary. A robust likelihood ratio test is used to differentiate between noise, artifacts, and other complex unmodeled structures, thereby verifying the model estimate. The proposed methodology behaves well across scale-space, shows a high degree of insensitivity to adjacent structures and implicitly handles branching. When evaluated on synthetic imagery mimicking specific structural complexities in tumor microvasculature, it consistently produces ubvoxel accuracy estimates of centerlines and widths in the presence of closely-adjacent vessels, branch points, and noise. An edit-based validation demonstrated a precision level of 96.6% at a recall level of 95.4%. Overall, it is robust enough for large-scale application.     

方管内表面等离子体离子注入动力学GPU-PIC仿真

内表面改性近年日益受到人们重视。本文采用基于Graphic Processing Unit(GPU)的Particle-in-cell(PIC)模型对方形管内表面的离子注入动力学过程进行数值仿真研究。结果表明在注入过程中,辅助地电极周围形成离子空穴,随时间延长,离子空穴发生交联并不断扩展,直至所有离子注入到方管内壁。离子空穴的形成和扩展使得在管内部形成离子密度波,密度波的传播速度随时间增加。由于等离子体鞘层的不均匀重叠使得管内的初始鞘层厚度分布不均,其中位于拐角附近的鞘层较厚,从而又导致了方管内壁周向上的注入剂量和能量分布存在不均匀性,内壁平面附近位置的注入剂量和注入能量均相对较大,而拐角附近的离子注入剂量和能量最小。本文采用GPU加速PIC的算法取得了高达90的加速比,极大缩短了等离子体粒子模拟的计算时间。     

台湾桃园长庚医院

一、本案缘起长庚纪念医院为因应社会人口结构迅速老化、医疗科技及医务管理系统的发展,计划提供现代化的老人、慢性及复健训练空间,以提升医疗保健品质,故委托本所进行桃园长庚分院之规划设计,兴     

Mapping Scales of Urban Identity

Ricky Burdett , Professor of Urban Studies at LSE where he is Director of the Urban Age programme, is engaged in studying cities at different scales and regional contexts. Here he looks at what gives a city like London its unique sense of scale, and how it might be possible to design in the sort of vibrancy and spatial complexity that evolve in informal neighbourhoods over time. Through examples of local initiatives in Cape Town and Mumbai, he gives concrete evidence of what constitutes this approach.     

Digital memory device based on tobacco mosaic virus conjugated with nanoparticles

Nanostructured viruses are attractive for use as templates for ordering quantum dots to make self-assembled building blocks for next-generation electronic devices. So far, only a few types of electronic devices have been fabricated from biomolecules due to the lack of charge transport through biomolecular junctions. Here, we show a novel electronic memory effect by incorporating platinum nanoparticles into tobacco mosaic virus. The memory effect is based on conductance switching, which leads to the occurrence of bistable states with an on/off ratio larger than three orders of magnitude. The mechanism of this process is attributed to charge trapping in the nanoparticles for data storage and a tunnelling process in the high conductance state. Such hybrid bio-inorganic nanostructures show promise for applications in future nanoelectronics.     

Strategies for Integrating Metal Nanoparticles with Two-Photon Polymerization Process: Toward High Resolution Functional Additive Manufacturing

This study reports the successful fabrication of complex 3D metal nanoparticle–polymer nanocomposites using two-photon polymerization (2PP). Three complementary strategies are detailed: in situ formation of metal nanoparticles (MeNPs) through a single-step photoreduction process, integration of pre-formed MeNPs into 2PP resin, and site-selective MeNPs decoration of 3D 2PP structures. In the in situ formation strategy, a phase-transfer method is applied to transfer silver and copper ions from an aqueous phase into a toluene solvent to disperse them in photoreactive monomers.The addition of a photosensitive dye, coumarin 30, facilitated the reduction of silver ions and improved the distribution of silver nanoparticles (AgNPs). This strategy is successfully used to produce other MeNPs, such as Cu and Au. The integration of pre-formed MeNPs enabled highly controlled NP size distribution within the 2PP 3D structures with high-fidelity To enable selective decoration of 2PP 3D surfaces with MeNPs, a multimaterial strategy is developed, with one of the resins designed for thiol-ene reaction, which demonstrated selective binding to AuNPs. The successful development of complementary strategies for integration of MeNPs into 2PP resins offers exciting opportunities for fabrication of MeNP composites with sub-micron resolution for applications from photonics to metamaterials and drug delivery.