The electrically small magnetically loaded multiturn loop antenna

An analytical model of a class of electrically small multiturn loop antennas has been formulated and compared with experimental measurements over a frequency range of 3 to 86 MHz. Both air core and magnetically loaded eases were examined. Transmitted signal enhancement as high as 10 dB was predicted and observed by magnetic loading. Several interesting properties of the transmitting antenna were investigated experimentally and by analysis based upon the model. It is concluded that transmitted signals can be enhanced in the 2-30 MHz range, at reasonable power levels, as much as 10 dB with state-of-art ferrite materials. Secondly, the analytical model described in this paper should prove an effective design aid for a volumetrically constrained antenna of the class.     

HDVC converter station tests in the 0.1 to 5 MHz frequency

Radiofrequency (RF) quantities in and around an HVDC converter station were measured in the 0.1 to 5 MHz frequency range to provide baseline data for the formulation of a means to predict the RF performance of such stations. Special records were taken at selected points and traverses in the station. The RF voltages of buses were measured and ground-level electric field strength and magnetic flux density measurements were conducted. To obtain the maximum amount of information about a converter pole when it is considered as an RF source, swept frequency (broadband) measurements were selected as the prime records for the analysis of pole performance. The principal source of the RF noise is the firing valve. Additional impedance versus frequency measurements of station components were also performed for undertaking RF modeling of the converter station     

A new approach to a nondestructive reverse bias safe operating areatest system

An approach to a nondestructive reverse bias safe operating area (RBSOA) test system that greatly simplifies system construction while equaling the performance of previous systems has been developed. The approach is simpler because it utilizes a single solid state device as the primary component of the protection circuit instead of vacuum tubes. This is possible because the measurement technique utilized here effectively eliminates the turn-on delay of the protection circuit which includes the unacceptably long turn-on delay of the solid state device. The system also includes several new measurement modes that were not possible or available with previous systems     

Infusion of bicarbonate into newborn infants

A child had essentially her entire lip and most of her nose bitten off in one piece by a dog. This was replanted by microvascular anastomoses. Most of the fragment survived.     

Effect of wavelet bases on compressing digital mammograms

The purposes of this paper are four-fold: (a) develop a variety of wavelet methods, including standard, hyperbolic, and adaptive wavelet bases, for the compression of high-resolution digital mammograms, (b) apply different levels of compression to the images and determine the dependence of the information loss on the compression ratio, (c) determine qualitatively the types of artifacts and errors introduced to the compressed reconstructed images by the various wavelets and make a relative comparison, and (d) discriminate among the various wavelet bases and select those worthy of further analysis and study     

Computer-Aided Spread Spectrum Signal Design

The calculations required in the formulation of surface acoustic wave device signals have been removed from the design process into a large-scale digital computer. The designer is left to trade off application-critical signal characteristics while the computer presents the alternatives and controls fabrication of the interdigital transducers.     

Understanding the Mechanism of Solvent‐Mediated Adhesion of Vacuum Deposited Au and Pt Thin Films onto PMMA Substrates

The adhesion of vapor deposited Au and Pt thin films onto poly(methyl methacrylate) (PMMA) substrates can be significantly enhanced by either spin‐casting or vapor‐exposure to hydrohalocarbon solvents prior to metal deposition. X‐ray photoelectron spectroscopy (XPS) and evolved gas analysis Fourier transform infrared spectroscopy detect residual halogenated solvent at the PMMA surface which chemically activates the surface. Density functional theory (DFT) calculations show that the solvent molecules form a Lewis acid‐base adduct with the ester oxygens in PMMA. DFT predicts that the deposited metal atom (M) inserts into the C–halogen (X) bond on either CHCl₃ or CHBr₃ to form a O–M–X interaction. This is consistent with M–X bonding observed in high resolution XPS. A model is proposed in which the bond energy of the C–X bond of the solvent must be weak enough so that it can be cleaved by the metal atom to form a M–X bond. A negative control of PMMA exposed to CHF₃ is shown to have no effect on Au or Pt adhesion since the bond dissociation energy of the C–F bond is stronger than the C–Cl and C–Br bond energy compared to the metal halide bond energies.     

Survey-guided process consultation in a Veterans Administration medical center psychology service.

During an assessment of an organizational effectiveness intervention in a psychology service in a Veterans Administration hospital, 13 psychologists assigned to the psychology service provided survey, Work Environment Scale (WES), and structured interview data. A written evaluation report was provided to all Ss, and a feedback session was scheduled involving the chief, the consultants, and the staff. Three subsequent group consultations involving all Ss were conducted, with consultants serving as process commentators, not content experts. To assess the impact, the WES was readministered following consultation. Four scales showed significant differences in a positive-change direction. 24 mo later, a 2nd administration of the WES was completed. On 7 of 10 scales, the reported increase in job satisfaction between August 1982 and July 1984 was significant. (8 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)