Interactive digital filtering of gated cardiac studies during cine display

The use of a novel class of image processing hardware, the image computer, is illustrated by application to gated cardiac studies. Digital filtering of a nine-view study consisting of 144 frames, each 64x64 pixels in size, is performed using the Wiener filter. During image display the operator can change the filter parameters. Refiltering is then performed essentially instantaneously, permitting truly interactive filter selection. Comparable digital filtering using a fast conventional computer and display hardware is shown to be too slow to permit interactive filter modification. Image computers incorporate very large image memories with very tightly coupled, fast arithmetic processors and video display devices and allow very computation-intensive calculations to be performed interactively.     

A low-jitter 125-1250-MHz process-independent and ripple-poleless0.18-μm CMOS PLL based on a sample-reset loop filter

This paper describes a low-jitter phase-locked loop (PLL) implemented in a 0.18-μm CMOS process. A sample-reset loop filter architecture is used that averages the oscillator proportional control current which provides the feedforward zero over an entire update period and hence leads to a ripple-free control signal. The ripple-free control current eliminates the need for an additional filtering pole, leading to a nearly 90° phase margin which minimizes input jitter peaking and transient locking overshoot. The PLL damping factor is made insensitive to process variations by making it dependent only upon a bandgap voltage and ratios of circuit elements. This ensures tracking between the natural frequency and the stabilizing zero. The PLL has a frequency range of 125-1250 MHz, frequency resolution better than 500 kHz, and rms jitter less than 0.9% of the oscillator period     

High-yield assembly of multichip modules through known-good IC'sand effective test strategies

Multichip module technology has been shown to offer significant improvements for electronics equipment in the areas of miniaturized size, reduced weight, capability for higher frequency operation, improved thermal performance, and improved reliability. Production applications for multichip modules (MCMs) have grown from high-end computer and aerospace modules to include such diverse products as telecommunications, automotive, and consumer electronics modules. One of the keys to economic success in all applications is the achievement of high manufacturing yields. Yield losses must be kept very low compared with module costs in order to remain economically competitive. Two parameters with a very strong impact on manufacturing yield, known-good components entering assembly and test strategies at various levels of assembly, are discussed. Current industry practice is surveyed and recent progress on MCM infrastructure development is summarized     

Calcium adsorption and displacement: characterization of lipid monolayers and their interaction with membrane-active peptides/proteins

Background  

The first target of antimicrobial peptides (AMPs) is the bacterial membrane. In the case of Gram-negative bacteria this is the outer membrane (OM), the lipid composition of which is extremely asymmetric: Whereas the inner leaflet is composed of a phospholipid mixture, the outer leaflet is made up solely from lipopolysaccharides (LPSs). LPS, therefore, represents the first target of AMPs. The binding and intercalation of polycationic AMPs is driven by the number and position of negatively charged groups of the LPS. Also, proteins other than cationic AMPs can interact with LPS, e.g. leading eventually to a neutralization of the endotoxic effects of LPS. We compared different biophysical techniques to gain insight into the properties of the electrical surface potentials of lipid monolayers and aggregates composed of LPSs and various phospholipids and their interaction with peptides and proteins.     

A new function block modeling language based on Petri nets for automatic code generation

A component based modeling language with the component interfaces derived from the elements of the Petri net theory called CNet is presented in this paper. In contrast to IEC 61499 function blocks that define the flow of events and data separately, CNet models them combined as colored tokens. The event-discrete behavior of CNet components is described by a special class of colored Petri nets with timed arcs and sharpened semantics in order to allow automatic generation of possibly concurrent Java code. In this paper, the state space of CNet components is analyzed and a novel event-discrete "handler-based" execution model that implicitly models an automaton is introduced.     

Every Reidemeister move is needed for each knot type

We show that every knot type admits a pair of diagrams that cannot be made identical without using Reidemeister -moves. The proof is compatible with known results for the other move types, in the sense that every knot type admits a pair of diagrams that cannot be made identical without using all of the move types.

     

Hermetic-equivalent packaging of GPS MCM-L modules for highreliability avionics applications

Results are presented of comparative reliability testing of multichip modules (MCM's) fabricated with laminate substrates, and protected with various bare-die coatings. The demonstration MCM's included two design versions (flip-chip and wire-bond) of the digital portion of global positioning system (GPS) receiver multichip modules. This paper summarizes the results for the wire-bonded constructions. Standard encapsulants and new inorganic coatings (Dow Coming's ChipSeal(R) hermetic coating materials') were evaluated in environmental stress exposures corresponding to high reliability avionics applications. Full wafer probe testing was performed both before and after the supplemental ChipSeal processing and dip-chip wafer bump processing steps. ChipSeal and flip-chip wafer processing steps were shown to cause no yield degradation on wafer lots of five different IC types used in the overall program. The environmental test results demonstrate that MCM-L units with bare die packaging can be designed for very robust reliability applications such as military and other high reliability avionics     

Moisture ingress into organic laminates

The electronic industry's most common laminates (FR-4, HTFR-4, PI, CE, and BT) were investigated for their equilibrium levels of moisture and diffusion rates and monitored for their moisture content as a function of electrical capacitance. Isothermal sorption tests were performed on the laminates to find the equilibrium moisture content in each laminate at various environmental conditions. The moisture content of each laminate was evaluated as a function of electrical capacitance via a capacitance monitoring plate attached to each laminate. A model was developed to assess the equilibrium content as a function of both temperature and humidity. Data from the sorption-time experiments was used to evaluate a diffusion coefficient for each laminate. The Fickian model was used to facilitate the evaluation. The results of the laminate moisture content analyses were subsequently applied to a printed wiring board (PWB) with a capacitor plate on each of its laminates. The capacitance method of moisture measurement in PWB shows slower moisture ingress than the theoretical moisture diffusion based on laminate experiments