Packaged Millimeter Wave Thermal MEMS Switches

This abstract describes MEMS thermally actuated millimeter wave switches. The switches are constructed using a stress controlled dielectric membrane, with patterned metallic contacts. The resulting switches can be operated at low voltage, without sacrificing the spring constant. The structure allows to build resistive switches up to millimeter wave. Full wave simulations were performed using FEM and MoM codes, and agree well with measurements. A wafer scale packaging technique has been developed to protect the components during the dicing stage, and for long term durability. The measured isolation are better than 35 dB between 30 and 40 GHz

Induction of leafy galls in Acacia mearnsii De Wild seedlings infected by Rhodococcus fascians

Plantlets of blackwattle (Acacia mearnsii De Wild) were inoculated with the bacterium Rhodococcus fascians and cultured in vitro. Leafy galls appeared at the cotyledonary nodes in 75% of the infected plants. The galls were separated from the plants and cultured on a medium containing three-quarters-strength MS salts (Murashige and Skoog, 1962), MS vitamins, 2% sucrose and an antibiotic (cephalothin), supplemented with or without 0.2% activated charcoal. Histological studies conducted from the sixth to the twenty-second day after plant infection revealed the presence of newly formed meristematic centers, first in the axillary region, then on the petioles and lamina of the leaflets around the apical meristem. Approximately 37% of the galls developed one shoot with both concentrations of cephalothin.<br>Plantas recém germinadas de acácia negra (Acacia mearnsii De Wild.) foram inoculadas com a bactéria Rhodococcus fascians e cultivadas in vitro. Galhas cobertas por folhas apareceram na altura do nó cotiledonar em 75% das plantas infectadas. As galhas foram separadas das plantas e cultivadas num meio de cultura contendo os sais do meio MS (Murashige e Skoog, 1962) reduzidos a 3/4, as vitaminas do mesmo meio, 2% de sacarose e um antibiótico (cefalotina), adicionado ou não de 0,2% de carvão ativo. Estudos histológicos realizados entre o sexto e o vigésimo segundo dia depois da inoculação, revelaram a presença de centros meristemáticos novos, primeiro nas regiões axilares, em seguida nos pecíolos e limbos dos folíolos ao redor do meristema apical. Aproximadamente 37% das galhas desenvolveram um broto na presença de cefalotina