245 research outputs found
Over-the-Counter Market Quotations
Chapter VII of the Report of Special Study of Securities Markets of the Securities and Exchange Commission focused attention upon the little understood and often perplexing problems presented by the quotations for over-the-counter stocks which appear regularly in the newspapers-the so-called retail quotations system. The Report was quite critical of the existing retail quotations system, concluding that it was inconsistent with the general philosophy of full disclosure elsewhere applied in the administration of the federal securities laws and, in fact, operated to conceal what elsewhere in the securities business is considered essential to be disclosed. While there does not appear to be unanimity in the securities industry with respect to the efficacy of the system, it is vigorously defended by its supporters as important, if not essential, to the business survival of smaller over-the-counter dealers and to the liquidity of the markets in many securities. It seems clear, therefore, that the problem warrants the attention which it will undoubtedly receive, both from the National Association of Securities Dealers (NASD) and from the Securities and Exchange Commission
Remote Monitoring and Control of Irradiation Experiments
As computer technology plays an increasing important role in particle accelerator facilities, instrumentation systems can be expected to include web connections and other remote capability features. The Michigan Ion Beam Laboratory at the University of Michigan in Ann Arbor has developed remote monitor and control capability by using a combination of commercial software packages and in‐house software development. Irradiation parameters such as ion current on the samples and apertures, sample temperature read from an optical pyrometer, and chamber pressure can all be accessed and monitored remotely through a web site, as can ion source parameters such as power supply currents and voltages or feed gas pressure. With administrator permission, the control parameters of the ion source or the readouts from the irradiation stage can be modified in real time during an experiment. A description will be given of the various ways in which this type of remote monitoring and control has been accomplished at the Michigan Ion Beam Laboratory. © 2003 American Institute of PhysicsPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87309/2/1046_1.pd
A high intensity radiation effects facility
The facility of the Michigan Ion Beam Laboratory at the University of Michigan has been upgraded to conduct high intensity radiation effects studies on materials. This upgrade is necessary to pursue higher radiation damage levels than the studies previously conducted. To achieve this capability a new volume ion source was installed which can produce several times more H−H− current than the previous duoplasmatron. We will describe the objectives of the research and the facility as well as applications to a variety of radiation damage problems. © 2001 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87674/2/687_1.pd
Surface analysis for students in Nuclear Engineering and Radiological Sciences
Students in Nuclear Engineering and Radiological Sciences at the University of Michigan are required to learn about the various applications of radiation. Because of the broad applicability of accelerators to surface analysis, one of these courses includes a laboratory session on surface analysis techniques such as Rutherford Backscattering Analysis (RBS) and Nuclear Reaction Analysis (NRA). In this laboratory session, the students determine the concentration of nitrogen atoms in various targets using RBS and NRA by way of the 14N(d,α)12C reaction. The laboratory is conducted in a hands‐on format in which the students conduct the experiment and take the data. This paper describes the approach to teaching the theory and experimental methods behind the techniques, the conduct of the experiment and the analysis of the data. © 2003 American Institute of PhysicsPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87310/2/856_1.pd
Optical properties of Ti and N implanted soda lime glass
Soda lime glass was implanted sequentially with Ti+ and N+ to doses ranging from 2 to 30×1016 cm−2 in order to study the resulting optical properties. Analysis of the implant distributions was made by using Rutherford backscattering and x‐ray photoelectron spectroscopy and revealed profiles which closely followed each other as designed by the selection of implant energies. Analysis of optical properties showed that the highest dose resulted in an increase in the fraction of infrared reflected by more than a factor of 4 versus 1.7 for the visible regime. The percentage of the total solar radiation rejected exceeded 60% at the highest dose, indicating that the buried layer is highly effective in reducing solar load. © 1995 American Institute of Physics. Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71178/2/APPLAB-66-2-142-1.pd
Formation of buried TiN in glass by ion implantation to reduce solar load
Ti and N were implanted into soda lime glass to doses up to 4.5×1017 cm−2 to reduce solar load and infrared transmission. Analysis of the Ti+N implant distributions by Rutherford backscattering spectrometry and x‐ray photoelectron spectroscopy (XPS) revealed profiles which closely followed each other as designed by the selection of implant energies. XPS, x‐ray diffraction, and selected area electron diffraction in transmission electron microscopy also confirmed the existence of a crystalline B1‐type, cubic TiN layer, 140 nm wide, at doses greater than 9×1016 cm−2. Optical measurements showed that the fraction of infrared radiation reflected was increased by almost a factor of 4 compared to an increase of 1.8 in the visible region. The percentage of the total solar energy rejected reached 80% at the highest dose, indicating that the buried TiN layer is highly effective in reducing solar energy transmission. © 1996 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69679/2/JAPIAU-80-5-2768-1.pd
Origins of luminescence from nitrogen-ion-implanted epitaxial GaAsGaAs
We have examined the origins of luminescence in N-ion-implanted epitaxial GaAsGaAs, using a combination of cross-sectional transmission electron microscopy and low-energy electron-excited nanoscale-luminescence spectroscopy. A comparison of reference, as-implanted, and implanted-plus-annealed samples reveals a variety of emissions. In all samples, we observe the GaAsGaAs fundamental band-gap emission, as well as several emissions related to GaAsGaAs native defects. In the as-implanted and implanted-plus-annealed samples, an emission related to the implantation-induced defects, is also observed. Interestingly, in the implanted-plus-annealed samples, we identify a near-infrared emission associated with GaAsNGaAsN nanocrystallites.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69942/2/APPLAB-85-14-2774-1.pd
Matrix-seeded growth of nitride semiconductor nanostructures using ion beams
We have examined the matrix-seeded growth of narrow-gap nitride nanostructures in nitrogen ion implanted GaAs and InAs. Low-energy implantation followed by rapid thermal annealing (RTA) results in the formation of 2–3 nm sized amorphous precipitates in a crystalline matrix. On the other hand, high-energy implantation results in an amorphous layer, with or without crystalline remnants. When the ion-beam-synthesized amorphous matrix is a continuous amorphous layer, subsequent RTA leads to the formation of 4–5 nm zinc blende (ZB)-GaN-rich crystallites in an amorphous matrix. When this matrix contains crystalline remnants, subsequent RTA leads to the formation of 2–4 nm ZB-GaN-rich crystallites within the amorphous regions. These results suggest that the matrix plays an important role in the nucleation and growth of narrow-gap nitride nanostructures, and that matrix-seeded growth may provide an opportunity to control the structure and properties of the nanostructures.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87633/2/064301_1.pd
A Conversation: Living Through Lacrosse
Living through Lacrosse featured a panel of those involved directly with the Duke lacrosse incident, ranging from the senior vice president for public affairs and government relations of Duke University to a former Duke student who was serving as a staff member of the Duke Chronicle in 2007.
Members of the panel assessed what happened during the course of the incident and then discussed what could be learned from this case and what might have been done differently. Questions/themes/discussion topics What were the individual roles of the panelists during the lacrosse incident? In hindsight, what would the panelists have done differently? What can be learned from the Duke lacrosse case for both similar and non-similar cases going forward
Corrosion and mechanical behavior of ion implanted bearing steels for improved fretting behavior
Ion implantation of AISI 52100 and 1070 steels was conducted in order to improve the corrosion, wear and ultimately the fretting behavior of the steels. Implantations consisted of 1 x 1017 Ta+ cm-2, 3 x 1017 Ti+ cm-2 + 1.5 x 1017 C+ cm-2, and 3.1 x 1017 Ti+ cm-2 + 1.55 x 1017 N+2 cm-2. All implantations were successful in improving the corrosion resistance. On average, the peak anodic current was reduced by over 300 mV, the passivation potential was reduced, and the pitting potential was increased by over 1000 mV in 0.01 M NaCl. Ti + C and Ti + N implantations increased the load-carrying capacity in lubricated scuffing tests by 60% and 40% respectively. Ta produced no improvement in scuffing resistance. Ti + N implantation increased the hardness by 25% over the unimplanted steel and both Ti + C and Ta implantation reduced the surface hardness. Fretting wear was reduced only slightly in the Ta implanted sample and increased in both the Ti + C and Ti + N implanted samples with the latter showing 4-5 times the weight loss as the unimplanted sample. The correlation between fretting and hardness supports a mechanism in which the hard surface layer breaks into fine particles which act as an abrasive under the intense load of the balls.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31416/1/0000333.pd
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