Tunable periodic microstrip structure on GaAs wafer

A one dimensional tunable periodic structure in microstip technology on gallium arsenide (GaAs) substrate is numerically investigated. The unit cell contains a number of patches positioned between the ground plane and the microstrip line. The patches, representing reactive loads, can be selectively short-circuited by externally-controlled FET switches integrated in the hosting substrate. The possibility of controlling the position of the band-gap, and implicitly the value of the e®ective dielectric constant along the line, for different combinations of the switches is demonstrate

General Public Awareness of Sources of Radiation in Their Environment

Author Institution: Departments of Agricultural Engineering, School of Natural Resources, Engineering Graphics, and Mechanical Engineering, The Ohio State UniversityA telephone survey (poll) of randomly selected Ohio citizens was conducted to determine their awareness and knowledge of sources of radiation in their environment. During October 1992, 1,450 households were contacted resulting in 879 complete interviews. Nearly half of those Ohio citizens surveyed have heard something about disposal of low-level radioactive waste. Knowledge about radiation exposure and sources was found to be related to general education level. College graduates tend to be slightly more aware of sources and exposure than adults with less than a high school education. Radiation exposure from bricks used in buildings, flying in an airplane, and smoke detectors was identified by fewer than 20% of respondents overall

Leitfaden für inklusive Kindertageseinrichtungen. Bestandsaufnahme und Entwicklung. Eine Expertise der Weiterbildungsinitiative Frühpädagogische Fachkräfte (WiFF)

Der Leitfaden für inklusive Kindertageseinrichtungen [...] richtet sich an alle Kindertageseinrichtungen (Kitas) - also sowohl Krippen und Kindergärten als auch Horte - und soll dazu beitragen, dass Entwicklungsprozesse in Einrichtungsteams angestoßen werden, die eine gemeinsame Arbeit am Leitbild Inklusion ermöglichen. Im Mittelpunkt des Leitfadens stehen die Qualitätsstandards und Leitfragen für inklusive Kitas. Sie dienen als Arbeitsgrundlage und Anregung für die konkrete Entwicklung in der jeweiligen Einrichtung. (DIPF/Verlag

Bloom-Gilman duality of inelastic structure functions in nucleon and nuclei

The Bloom-Gilman local duality of the inelastic structure function of the proton, the deuteron and light complex nuclei is investigated using available experimental data in the squared four-momentum transfer range from 0.3 to 5 (GeV/c)**2. The results of our analysis suggest that the onset of the Bloom-Gilman local duality is anticipated in complex nuclei with respect to the case of the protonand the deuteron. A possible interpretation of this result in terms of a rescaling effect is discussed with particular emphasis to the possibility of reproducing the damping of the nucleon-resonance transitions observed in recent electroproduction data off nuclei.Comment: revised version, to appear in Physical Review

Bandstop Filter Synthesis Scheme for Reactively Loaded Microstrip Line Based 1-D Periodic Structures

A 1-D finite electromagnetic bandgap (EBG) periodic structure is studied. In the structure, EBG behaviour arises from a unit cell comprised of a metallic patch sandwiched between microstrip line and ground plane. Reactive loading offered by patch size determines the bandgap position. A detailed parametric study of various physical structure parameters is presented as a basis to develop a interrelation between physical parameters of the structure and cutoff frequencies. Closed-form synthesis equations are then formulated using curve fitting techniques. Subsequently, a step-by-step design methodology is presented to get a close first pass approximation of structure dimensions for a given specification. This design method reduces the effort required for a designer to perform extensive electromagnetic simulations at early stages of the design. The proposed synthesis method is tested for a variety of commercially available substrates and different frequency ranges for validation. Comparison with electromagnetic (EM) simulations and measurement show that the proposed synthesis method provides first pass approximation of the physical structure dimensions with 94% accuracy

Pneumothorax as a Complication of Radiation Therapy for Primary Lung Cancer

A case of spontaneous pneumothorax complicating irradiation for bronchogenic carcinoma is presented. Pneumothorax developed in a collapsed lung caused by a central bronchogenic carcinoma. The cause is presumably secondary to either a bronchopleural fistula by tumour or sudden expansion of the lung following irradiation. Various tumours of the lung have been associated with spontaneous pneumothorax, including metastatic osteogenic sarcoma 12 , eosinophilic granuloma 4 , teratoma 11 , other metastatic sarcomas 3 , lymphoma following radiation therapy 8 , and primary bronchogenic carcinomas 1,2,3,5,6,7,9,10 . We have encountered a case of spontaneous pneumothorax complicating irradiation for bronchogenic carcinoma. To our knowledge, this is the first report in the English radiologic literature, and the second, in the English literature, of a case of spontaneous pneumothorax following radiation therapy for proven bronchogenic carcinoma.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75343/1/j.1440-1673.1976.tb02589.x.pd

A Compact Reconfigurable 1-D Periodic Structure in GaAs MMIC With Stopband Switching, Dual-Band Operation and Tuning Capabilities

This paper presents a systematic study of a compact and reconfigurable periodic structure in GaAs MMIC technology. Compactness is achieved by the introduction of spiral inductors in a conventional unit cell without disturbing the reactive loading mechanism. The proposed architecture exhibits a 28.3% wider stopband with 62.6% smaller footprint compared to a conventional structure. The compactness and bandwidth improvement in the proposed structure is explained with the help of dispersion and circuit analysis. The reconfigurability built into the design using PIN diodes allows stopband switching, dual-band operation and tuning capabilities with the mere use of a single reactive load in its unit cell. To the best of the authors knowledge, it is the first time a reconfigurable MMIC implementation is realized using the proposed structure or even the conventional design. As a guide to design, sensitivity analysis to filter performance is presented for important structure parameters. Switching element parasitics are discussed in two ways: firstly, with the design and measurement of structures with idealized switching conditions and in second, with the circuit and full-wave EM modelling of the finite periodic structure with the actual PIN diodes. The on-chip measurements of the fully reconfigurable filter show excellent agreement with simulations

Silicon web process development

Silicon dendritic web, a single crystal ribbon shaped during growth by crystallographic forces and surface tension (rather than dies), is a highly promising base material for efficient low cost solar cells. The form of the product smooth, flexible strips 100 to 200 microns thick, conserves expensive silicon and facilitates automation of crystal growth and the subsequent manufacturing of solar cells. These characteristics, coupled with the highest demonstrated ribbon solar cell efficiency-15.5%-make silicon web a leading candidate to achieve, or better, the 1986 Low Cost Solar Array (LSA) Project cost objective of 50 cents per peak watt of photovoltaic output power. The main objective of the Web Program, technology development to significantly increase web output rate, and to show the feasibility for simultaneous melt replenishment and growth, have largely been accomplished. Recently, web output rates of 23.6 sq cm/min, nearly three times the 8 sq cm/min maximum rate of a year ago, were achieved. Webs 4 cm wide or greater were grown on a number of occassions

Superscaling in inclusive electron-nucleus scattering

We investigate the degree to which the scaling functions $F(\psi')$ derived from cross sections for inclusive electron-nucleus quasi-elastic scattering define the same function for different nuclei. In the region where the scaling variable $\psi'< 0$, we find that this superscaling is experimentally realized to a high degree.Comment: Corrected previously mislabeled figures and cross references; 9 pages, 4 color figures, using BoxedEPS and REVTeX; email correspondence to [email protected]