SAR antenna calibration techniques

Calibration of SAR antennas requires a measurement of gain, elevation and azimuth pattern shape, boresight error, cross-polarization levels, and phase vs. angle and frequency. For spaceborne SAR antennas of SEASAT size operating at C-band or higher, some of these measurements can become extremely difficult using conventional far-field antenna test ranges. Near-field scanning techniques offer an alternative approach and for C-band or X-band SARs, give much improved accuracy and precision as compared to that obtainable with a far-field approach

Academic Support at Leeds Metropolitan Library

Leeds Metropolitan’s Library Academic Support Stream is made up of Academic Librarians and Information Services Librarians who provide academic support to the university’s six faculties. The team use innovative methods of working together to engage students and enhance their experience. The team only formed a year ago so this is a good time to reflect on our success so far. The library service at Leeds Met is continually developing and offers new challenges and opportunities for staff providing library academic support. Innovation has even become part of our new name – ‘Libraries and Learning Innovation’. We still offer all the traditions types of library academic support, but there is an increasing emphasis on finding innovative ways of supporting students and publicising what we can offer. This year the Library Academic Support Stream won a University Attitude Character and Talents Award for Future Focus

A MOS cursive-character generator

Cursive characters can be made to be more readable, more attractive, and better suited to the operation of graphic CRT terminals than the usual dot-matrix type; a system using cursive-type characters achieves much higher writing rate while requiring much less bandwidth than that using dot-matrix-type characters. This paper presents an economical method of generating the x, y, and z analog signals for forming cursive characters with the deflection system of a CRT. A circuit design embodying a complete 48-stroke character generator on a single MOS integrated circuit is described. The IC accepts 7-bit ASCII code and outputs x, y, and z analog signals to generate any one of 32 standard ASCII characters in 5 μs. Additional groups of 32 characters can be added by merely paralleling additional chips. The entire 32 character digital and analog function has been implemented on a single self-contained 16-pin silicon-gate MOS chip 125 X 165 mil in size. Character encoding on the chip is accomplished in one mask at the diffusion step, and a straightforward mask-generation procedure has been developed

Avian Influenza: Human Pandemic Concerns

The likelihood that the next human influenza pandemic virus will emerge from the Asian strain of the H5N1 high pathogenic bird influenza virus that is causing widespread outbreaks in Eurasia remains unknown. (See Glossary for italicized terms.) Because these bird influenza outbreaks remain primarily an animal disease, there is hope that a human pandemic can be prevented. Eradication of the H5N1 high pathogenic bird influenza virus needs to occur at the farm level in the countries where it is currently circulating. Funding of prevention, surveillance, and eradication efforts in the countries where outbreaks are occurring or in at-risk countries will provide tools needed to facilitate the eradication process of this virus where it is detected and will prevent further spread and subsequent economic loss. Most importantly, stopping the spread of this virus will decrease the opportunity for the virus to emerge as the next human pandemic influenza virus. Every new poultry infection, and subsequent human exposure, gives the virus an opportunity to adapt directly to humans or to exchange genetic material with other influenza viruses, including human influenza subtypes; either event increases the chances that the bird influenza will become a significant human disease

Single-Chip Cursive Character Generator

A unique circuit design using conventional MOS technology has been found to yield a sequential read-only analog memory which can generate the x- and y-axis deflection voltages for the stroke-by-stroke synthesis of alphanumeric characters

Deliverable, Low-Cost Student Response Systems

This paper describes three deliverable, low-cost student response systems - software tools for providing Instructors with immediate feedback on students. Each of these tools has been and Is being developed at the United States Military Academy for similar purposes. First, the software can be used as a lesson structuring tool. Instructors can tailor their presentations to classes based on the results of their students\u27 lesson preparation the night before. This results in classes that are specifically targeted at those subjects the students had difficulty with. As a result, the instructors can better utilize their class period and the students will find the classroom Instruction more valuable. Second, we have used the software during class to validate that the students understand a particular learning objective before moving on to the next learning objective or to tabulate the class\u27 opinion on a student submission anonymously. Due to the automatic, real-time grading of results, the student response system allows greater control over class presentations by providing relevant feedback to the instructor and the student in real-time. Finally, the student response system can be incorporated into courses taught using hypermedia. As before, the system provides critical feedback to the student and Instructor alike and allows for the tailoring of study sessions and course material respectively

Exchange-coupling constants, spin density map, and Q dependence of the inelastic neutron scattering intensity in single-molecule magnets

The Q dependence of the inelastic neutron scattering (INS) intensity of transitions within the ground-state spin multiplet of single-molecule magnets (SMMs) is considered. For these transitions, the Q dependence is related to the spin density map in the ground state, which in turn is governed by the Heisenberg exchange interactions in the cluster. This provides the possibility to infer the exchange-coupling constants from the Q dependence of the INS transitions within the spin ground state. The potential of this strategy is explored for the M = +-10 -> +- 9 transition within the S = 10 multiplet of the molecule Mn12 as an example. The Q dependence is calculated for powder as well as single-crystal Mn12 samples for various exchange-coupling situations discussed in the literature. The results are compared to literature data on a powder sample of Mn12 and to measurements on an oriented array of about 500 single-crystals of Mn12. The calculated Q dependence exhibits significant variation with the exchange-coupling constants, in particular for a single-crystal sample, but the experimental findings did not permit an unambiguous determination. However, although challenging, suitable experiments are within the reach of today's instruments.Comment: 11 pages, 6 figures, REVTEX4, to appear in PR

A two's complement pipeline multiplier

A serial-data pipeline multiplier was designed and implemented in p-channel silicon-gate MOS. It uses a radix-4 Booth algorithm for two's complement compatibility. The circuit is modular, and is configured to multiply one data word by two coefficient words simultaneously

Magnitude and Duration of Elevated Gastric pH in Patients Infected with Human Immunodeficiency Virus After Administration of Chewable, Dispersible, Buffered Didanosine Tablets

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90191/1/phco.24.16.1539.50959.pd