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Technology roadmaps for compound semiconductors
No full textThe roles cited for compound semiconductors in public versions of existing technology roadmaps from the National Electronics Manufacturing Initiative, Inc., Optoelectronics Industry Development Association, Microelectronics Advanced Research Initiative on Optoelectronic Interconnects, and Optoelectronics Industry and Technology Development Association (OITDA) are discussed and compared within the context of trends in the Si CMOS industry. In particular, the extent to which these technology roadmaps treat compound semiconductors at the materials processing and device levels will be presented for specific applications. For example, OITDA's Optical Communications Technology Roadmap directly connects the information demand of delivering 100 Mbit/s to the home to the requirement of producing 200 GHz heterojunction bipolar transistors with 30 nm bases and InP high electron mobility transistors with 100 nm gates. Some general actions for progress towards the proposed International Technology Roadmap for Compound Semiconductors (ITRCS) and methods for determining the value of an ITRCS will be suggested. But, in the final analysis, the value added by an ITRCS will depend on how industry leaders respond. The technical challenges and economic opportunities of delivering high quality digital video to consumers provide concrete examples of where the above actions and methods could be applied
Ab initio values of the thermophysical properties of helium as standards
No full textRecent quantum mechanical calculations of the interaction energy of pairs of helium atoms are accurate and some include reliable estimates of their uncertainty. We combined these ab initio results with earlier published results to obtain a helium-helium interatomic potential that includes relativistic retardation effects over all ranges of interaction. From this potential, we calculated the thermophysical properties of helium, i.e., the second virial coefficients, the dilute-gas viscosities, and the dilute-gas thermal conductivities of He-3, He-4, and their equimolar mixture from 1 K to 10(4) K. We also calculated the diffusion and thermal diffusion coefficients of mixtures of He-3 and He-4. For the pure fluids, the uncertainties of the calculated values are dominated by the uncertainties of the potential; for the mixtures, the uncertainties of the transport properties also include contributions from approximations in the transport theory. In all cases, the uncertainties are smaller than the corresponding experimental uncertainties; therefore, we recommend the ab initio results be used as standards for calibrating instruments relying on these thermophysical properties. We present the calculated thermophysical properties in easy-to-use tabular form
Spectroscopy in the second minimum: Isotopic limits, lifetimes, and magnetic properties of superdeformed T1 nuclei
No full textIn-beam gamma-ray spectroscopic studies of superdeformed bands in the mass 190 region are discussed with emphasis on recent results for TI nuclei. Among those results, superdeformation at the edge of the region (in Tl-189) and the first measurement of a superdeformed quadrupole moment in an odd-Z nucleus (Tl-191) is presented. The experiments were conducted with the Gammasphere army at the Lawrence Berkeley National Laboratory
Sub-nanosecond lifetime measurement using the recoil-distance method
No full textThe electromagnetic properties of low-lying nuclear states are a sensitive probe of both collective and single-particle degrees of freedom in nuclear structure. The recoil-distance technique provides a very reliable, direct and precise method for measuring lifetimes of nuclear states with lifetimes ranging from less than one to several hundred picoseconds. This method complements the powerful, but complicated, heavy-ion induced Coulomb excitation technique for measuring electromagnetic properties. The recoil distance technique has been combined with heavy-ion induced Coulomb excitation to study a variety of problems. Examples discussed are: study of the two-phonon triplet in Pd-110, coupling of the beta and gamma degrees of freedom in W-182,W-184, highly deformed gamma bands in Ho-165, octupole collectivity in Zr-96, and opposite parity states in Eu-153. Consistency between the Coulomb excitation results and the lifetime measurements confirms the reliability of the complex analysis often encountered in heavy-ion induced Coulomb excitation work
Noise-optimized silicon radiometers
No full textThis paper describes a new, experimentally verified, noise analysis and the design considerations of the dynamic characteristics of silicon radiometers. Transimpedance gain, loop gain, and voltage gain were optimized versus frequency for photodiode current meters measuring ac and de optical radiation. Silicon radiometers with improved dynamic characteristics were built and tested. The frequency-dependent photocurrent gains were measured. The noise floor was optimized in an ac measurement mode using photodiodes of different shunt resistance and operational amplifiers with low l/f voltage and current noise. In the dark (without any signal), the noise floor of the optimized silicon radiometers was dominated by the Johnson noise of the source resistance. The Johnson noise was decreased and equalized to the amplified l/f input noise at a 9 Hz chopping frequency and 30 s integration time constant, resulting in an equivalent root-mean-square (rms) photocurrent noise of 8 x 10(-17) A. The lowest noise floor of 5 x 10(-17) A, equal to a noise equivalent power (NEP) of 1.4 x 10(-16) W at the 730 nm peak responsivity, was obtained at a 100 s integration time constant. The radiometers, optimized for ac measurements, were tested in a de measurement mode as well. Performances in ac and de measurement modes were compared. In the ac mode, a ten times shorter (40 s) overall measurement time was needed than in the de mode (400 s) to obtain the same 10(-16) A noise floor
Measurement of calcium activity in oral fluids by ion selective electrode: Method evaluation and simplified calculation of ion activity products
No full textThe activity of calcium in prague fluid is needed to calculate the saturation level of that fluid relative to the tooth mineral. One method to determine the calcium activity in very small plaque fluid samples is by micro ion-selective electrode (ISE). Two commercially available calcium ionophores, a neutral-carrier and a charged-carrier, were evaluated in micro ISEs and compared to a commercially available macro ISE using saliva as a model for plaque fluid. The neutral-carrier containing ISEs gave results consistent with those of the macro ISE. Calcium activity measurements made with micro ISEs that contained the neutral ion-carrier of whole plaque samples and plaque fluid samples obtained by centrifugation of whole plaque showed that the activities did not change due to centrifugation. Estimates of the saturation with respect to hydroxyapatite were made from these measurements. A simplified calculation method is presented to estimate the ion activity product (IAP) of the calcium-phosphate minerals. The method is based on the relative abundance of some of the possible calcium-binding species and a fixed ionic strength for plaque fluid. Calculations show that within a normal pH range for plaque fluid (5.0 to 7.5) the differences in the IAP calculations for hydroxyapatite using the simplified method are less than those estimated from propagation of uncertainty calculations
Joan R. Rosenblatt
No full textJoan R. Rosenblatt
Inducted: 2000
Citation: For research on nonparametric statistical theory, applications of statistical techniques in physical and engineering sciences, and reliability of complex systems, and for leadership of the Computing and Applied Mathematics Laboratory.
Tenure: 1955-1995
Birth: 1926, New York, New York
Education:
Barnard College, AB (Mathematics), 1946
University of North Carolina, PhD (Statistics), 1956
Positions held:
Chief, Statistical Engineering Section
Deputy Director, Center for Applied Mathematics [& successor units]
Director, Computing and Applied Mathematics Laboratory
Post-retirement: Guest Researcher, Statistical Engineering Division
Honors:
U.S. Department of Commerce: Silver Medal, 1969; Gold Medal, 1976
Washington Academy of Sciences Achievement Award, 1966
Federal Woman's Award, 1971
American Statistical Association Founders Award, 1991
Elected to Phi Beta Kappa and Sigma Xi
Memberships:
American Association for the Advancement of Science (Fellow)
American Statistical Association (Fellow; Vice-President)
Institute of Mathematical Statistics (Fellow)
Caucus for Women in Statistics (President)
American Mathematical Society
International Statistical Institute
Bernoulli Society for Probability and Mathematical Statistics
Royal Statistical Society, London
Society for Industrial and Applied Mathematics (SIAM)
Association for Women in Mathematics
Philosophical Society of Washington
Washington Academy of Sciences (Fellow)
Publications:
Author of many technical papers on nonparametric statistical theory, applications of statistical techniques in physical and engineering sciences, and reliability of complex systems; on Editorial Board of SIAM Journal on Applied Mathematics