Comment on new differential flip-flops from Yuan and Svensson

A family of differential latches has recently been proposed by Yuan and Svensson [1996]. The author shows that the proposed flip-flops using the dynamic slave latch suffer from a poor logic-level zero in the presence of glitches on the data inputs     

Histogram measurement of ADC nonlinearities using sine waves

This paper gives results concerning the measurement of differential and integral nonlinearity of ADC's using the histogram method with a sine wave input signal. We specify the amount of overdrive required as a function of the noise level and the desired accuracy and the number of samples required as a function of the desired accuracy, the desired confidence level, and the noise level. An analysis of the effect on the results of harmonic distortion of the applied signal is given. The error analysis assumes a mixture of coherent and random sampling rather than pure random sampling     

Low-power double-edge triggered flipflop

Low-power double-edge triggered flipflops are presented using weak feedback transistors which allow purely n-type transmission gates, but without static-power consumption. The switching capacitance of the weak transistors is minimised by using permanently ON transistors in series as resistive devices. Both static and semi-static circuits are presented     

L2imbo: A distributed systems platform for mobile computing

Mobile computing environments increasingly consist of a range of supporting technologies offering a diverse set of capabilities to applications and end-systems. Such environments are characterised by sudden and dramatic changes in the quality-of-service (QoS) available to applications and users. Recent work has shown that distributed systems platforms can assist applications to take advantage of these changes in QoS and, more specifically, facilitate applications to adapt to their environment. However, the current state-of-the-art in these platforms reflects their fixed network origins through their choice of synchronous connection-oriented communications paradigms. In this paper we argue that these paradigms are not well suited to operation in the emerging mobile environments. Furthermore, we offer an alternative programming paradigm based on tuple spaces which, we believe, offers a number of benefits within a mobile context. The paper presents the design, implementation and evaluation of a new platform based on this paradigm. This revised version was published online in June 2006 with corrections to the Cover Date.     

The Role of Elastic and Plastic Anisotropy of Snin Recrystallization and Damage Evolution DuringThermal Cycling in SAC305 Solder Joints

Because failures in lead-free solder joints occur at locations other than the most highly shear-strained regions, reliability prediction is challenging. To gain physical understanding of this phenomenon, physically based understanding of how elastic and plastic deformation anisotropy affect microstructural evolution during thermomechanical cycling is necessary. Upon solidification, SAC305 (Sn-3.0Ag-0.5Cu) solder joints are usually single or tricrystals. The evolution of microstructures and properties is characterized statistically using optical and orientation imaging microscopy. In situ synchrotron x-ray measurements during thermal cycling are used to examine how crystal orientation and thermal cycling history change strain history. Extensive characterization of a low-stress plastic ball grid array (PBGA) package design at different stages of cycling history is compared with preliminary experiments using higher-stress package designs. With time and thermal history, microstructural evolution occurs mostly from continuous recrystallization and particle coarsening that is unique to each joint, because of the specific interaction between local thermal and displacement boundary conditions and the strong anisotropic elastic, plastic, expansion, and diffusional properties of Sn crystals. The rate of development of recrystallized microstructures is a strong function of strain and aging. Cracks form at recrystallized (random) boundaries, and then percolate through recrystallized regions. Complications arising from electromigration and corrosion are also considered.     

Photoelectric properties of MISM phthalocyanine structure

Langmuir-Blodgett films have been prepared from copper tetra-4-t-butylphthalocyanine. A voltage dependence of capacitance can be attributed to the presence of a Schottky depletion layer. The barrier potential was determined as l·4eV, and the carrier concentration about 10²⁴m^?3     

Measurement of the thermal expansion coefficient of an all-sapphireoptical cavity

We present measurements of the frequency-temperature dependence of an all-sapphire Fabry-Perot optical cavity to be used as an optical frequency reference. Measurements were made by tracking the frequency of the cavity relative to a second high-stability cryogenic sapphire-spaced cavity-a technique with impressive resolution for measurements of the coefficient of thermal expansion (CTE). Measurements presented here cover the temperature range of 11 K to 26 K. We find that the CTE of the all-sapphire cavity for these temperatures is given by α_cavity=(7.7±0.9)×10^$ -¹³ T/sup (3.23±0.05/)     

Evaluation of fecal technics for the diagnosis of cat liver fluke infection

The comparative efficiency of 5 standard technics for the detection of feline liver fluke ova in feces was evaluated. The formalin-ether technic proved superior to direct smear, sugar flotation, zinc sulfate flotation, or detergent sedimentation technics. The formalin-ether technic correctly diagnosed all Platynosomum concinnum-infected cats studied, as confirmed by necropsy findings.