Sudden cardiac death in the adult with congenital heart disease

Preliminary results of a review of sudden cardiac death in the adult with congenital heart disease were presented at the Canadian Adult Congenital Heart (CACH) Network meeting during the Canadian Cardiovascular Society's annual meeting in October 1994. Of 125 patients who were known to have died, sufficient details were available for 92 to determine the circumstance of death. Sudden death occurred in 23 patients (estimated incidence 5.3 per 1000 patients followed per year) at an average age of 33.5 +/- 11.9 years. Surgical procedures included intracardiac repair in 12, palliative procedures in only six and no cardiac surgery in six. Nine patients with sudden death had Eisenmenger syndrome. Right or left ventricular abnormalities were present in 15 of 21 patients with premorbid echocardiographic evaluation. A prior history of ventricular arrhythmia was available in only three patients. Sudden death is a significant cause of mortality in adults with congenital heart disease. Determination of risk factors will be an important aspect of the patient database under development by the CACH Network.     

Computer‐assisted learning of Chinese idioms

Abstract Chinese idioms play an important role in Chinese vocabulary learning as well as having cultural and social functions. However, researchers found that Hong Kong students seldom use idioms. Not only are students writing characters incorrectly, they are using the idioms both incorrectly and inappropriately. A survey was conducted to examine the attitudes of Hong Kong students and teachers to learning Chinese idioms. According to the survey, primary teachers believed that computers can assist students in learning Chinese idioms more effectively than an idiom dictionary. Consequently, an experimental program for learning Chinese idioms was designed for students between 9 and 11 years old. As an evaluation, usability tests were carried out by interview and by survey. Both evaluations produced positive responses from the dependent and independent group of subjects which is an encouraging first step.     

Two-layer five-patch broadband microstrip antennas

An aperture coupled five-patch broadband microstrip antenna which makes use of stacked and coplanar techniques is studied. It is demonstrated that the antenna can attain a bandwidth of ~45%. The radiation patterns and SWR of the antenna are presented. A comparison between theoretical and experimental results is made     

Water Based Silicone Elastomer Controlled Release Tablet Film Coating III - Drug Release Mechanisms

The release of potassium chloride from polyethylene glycol-silicone elastomer coated tablets was achieved by the diffusion through water-filled pores formed in the hydrated coating and the osmotic pumping generated by the saturated salt solution. The relative contribution of these two mechanisms to the overall drug release rate was shown to be a function of the polyethylene glycol loading in the coating. As the polyethylene glycol loading level increased, the transpore diffusion became the predominant release mechanism. The capability of the polyethylene glycol-silicone elastomer coatings to provide controlled release for therapeutic agents of different water solubilities and dose levels was also demonstrated. Both the rate and extent of release of the active ingredients could be altered by the type of diluent used in the tablet matrix     

Parameter Modeling for Wafer Probe Test

This paper presents the simulation of parameters for wafer probe test by finite-element modeling with consideration of probe over-travel (OT) distance, scrub, contact friction coefficient, probe tip shapes, and diameter. The goal is to minimize the stresses in the device under the bond pad and eliminate wafer failure in probe test. In the probe test modeling, a nonlinear finite-element contact model is developed for the probe tip and wafer bond pad. Modeling results have shown that the probe test OT, probe tip shape and tip diameters, contact friction between the probe tip and bond pad, as well as the probe scrub of the probe tip on bond pad are important parameters that impact the failure of interlayer dielectric (ILD) layer under bond pad. Comparison between probe test damage and wire bonding failure shows the degree of damage to both probe test and wire bonding on the same bond pad structures. In addition that, a design of experiment (DOE) probe test with different ILD and metal thickness is carried. The correlation between the modeling and the DOE test is studied. The results show that the modeling solution agrees with the DOE probe test data. Modeling results have further revealed that probe test can induce the local tensile (or bending) first principal stress in ILD layer, which may be a root cause of the ILD failure in probe test.     

Stability of Microstructure of Ultrafine‐Grained Copper Under Fatigue and Thermal Exposition

Abstract: Effect of cyclic loading and thermal exposition on microstructure of bulk ultrafine‐grained Cu prepared by equal channel angular pressing was experimentally investigated by means of electron backscattering diffraction and by transmission electron microscopy. Stability of the microstructure under stress‐controlled cyclic loading with a tensile mean stress of 200 MPa was shown to be high. Neither dynamic grain coarsening nor development of bimodal microstructure was observed. However, annealing at 250 °C for 30 min resulted in formation of bimodal microstructure. Consequently, fatigue strength of annealed specimens was low.     

The High-Temperature Wear and Oxidation Behavior of CrC-Based HVOF Coatings

Three commercially available chromium carbide-based powders with different kinds of matrix (Cr₃C₂-25%NiCr; Cr₃C₂-25%CoNiCrAlY and Cr₃C₂-50%NiCrMoNb) were deposited by an HVOF JP-5000 spraying gun, evaluated and compared. The influence of heat treatment on the microstructure and properties, as well as the oxidation resistance in a hot steam environment (p = 24 MPa; T = 609 °C), was evaluated by SEM and XRD with respect to their potential application in the steam power industry. The sliding wear resistance measured at room and elevated (T = 600 °C) temperatures according to ASTM G-133. For all three kinds of chromium carbide-based coatings, the precipitation of secondary carbides from the supersaturated matrix was observed during the heat treatment. For Cr₃C₂-25%NiCr coating annealed in hot steam environment as well as for Cr₃C₂-25%CoNiCrAlY coating in both environments, the inner carbide oxidation was recorded. The sliding wear resistance was found equal at room temperature, regardless of the matrix composition and content, while at elevated temperatures, the higher wear was measured, varying in dependence on the matrix composition and content. The chromium carbide-based coating with modified matrix composition Cr₃C₂-50%NiCrMoNb is suitable to replace the Cr₃C₂-25%NiCr coating in a hot steam environment to eliminate the risk of failure caused by inner carbide oxidation.