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This study examines the distribution options of 85 large public retirement plans covering general state employees, teachers, and local government employees. The interest rates used to price annuities vary considerably across the plans. As a result, retirees with the same monthly benefit if a single life benefit is chosen will have substantially different monthly benefits if they select a joint and survivor annuity. We examine the impact of variation in the pricing of annuity options using both cross-plan differences in interest rates and the change in the choice of annuity options in one plan after the price of options changes due to new assumed interest rates and mortality rates.
Nuclear fuel plates based on a γU-Mo/Al mixture are proposed for research reactors. In this work their thermal behavior in the [425; 550°C] temperature range has been studied mainly by neutron and high energy X-ray diffraction. Even if complementary studies will be necessary, the kinetics of first the growth of the interaction layer between γU-Mo and Al and second of the γU-Mo destabilization have been accurately measured. This basic work should be helpful for defining manufacturing conditions for fuel plates with optimized composition.
Synchrotron-based X-ray techniques are used increasingly to characterize actinide element speciation in heterogeneous media related to nuclear waste disposal safety. Especially techniques offering added temporal, spatial and energy resolved information are advancing our understanding of f-element physics and chemistry in general and of actinide element waste disposal in particular. Examples of investigations of uranium containing systems using both highly (energy) resolved X-ray emission spectroscopy (HRXES) techniques and spatially resolved techniques with focused X-ray beams are presented in this paper: polarization dependent partial fluorescence yield X-ray absorption near edge structure (PD-PFY-XANES) spectroscopic studies of a single Cs2UO2Cl4 crystal, which experimentally reveal a splitting of the σ, π, and δ components of the 6d valence states , and characterization of UO2/Mo thin films prepared on different substrates using a combination of techniques (2D and 3D micro- and nano-X-ray fluorescence, XANES and both holographic and ptychographic tomography).
The purpose of this research was to determine whether trappers in northern Alaska acquired immunity to rabies virus from non-bite exposures while trapping and skinning arctic foxes (Alopex lagopus). In coastal Alaska recurring epizootics presumably provide trappers ample opportunity for contact with rabid animals. Serum neutralization analyses of blood samples collected from 26 individuals were conducted. All but three had negative rabies neutralizing antibody levels (< 0·05 I.U./ml). Two of these had previously received rabies vaccine but one individual who had trapped for about 47 years with an estimated harvest of over 3000 foxes and who had never received pre- or post-exposure rabies vaccination had a rabies serum neutralizing antibody concentration of 2·30 I.U./ml. This represents the first report of an unvaccinated person acquiring rabies virus antibody with a titre above the 0·5 I.U./ml level considered acceptable by the World Health Organization.
Phases that are in equilibrium with BaR2CuO6+x (R=lanthanides and Y), such as the “green-phase” and “brown-phase” structural variants of BaR2CuO5 in bulk samples, are attractive choices for flux-pinning for coated conductor applications because of the guaranteed chemical stability. In films, high-temperature x-ray diffraction studies of Ba2RCu3O6+x superconductor deposited on SrTiO3 substrate using the trifluoroacetate solution method demonstrate that while BaNd2CuO5 (“brown-phase” structure) develops at 735 °C and 100 Pa pO2, neither BaGd2CuO5 nor Ba(Nd1/3Eu1/3Gd1/3)2CuO5 (both green-phase structure) form at these conditions. As a result, Ba2(Nd1/3Eu1/3Gd1/3)Cu3O6+x in thin films is in equilibrium with the brown-phase, and Ba2GdCu3O6+x is in equilibrium with Gd2O3 in the Ba–Gd–Cu–O system, in contrast to the bulk systems. Different phase relationships in the vicinity of the Ba2RCu3O6+x phase imply different phases are available for flux-pinning applications. These differences will need to be considered carefully in designing optimized superconducting coated conductors.
The examination of high resolution spectra of two Ap stars, HD 965 and HD 217522, discloses a spectral appearance similar to Przybylski’s star. Here we present the preliminary results of a comparative study of all three stars. Further, we discuss the possibility of having a good spectroscopic indicator of magnetic fields in Ap stars. In all three studied stars the strong Lu II line at λ 5984 Å is present and very likely not affected by significant blends. Its hyperfine structure has been recently measured and we show the results of a model that accounts for the Paschen-Back effect on hyperfine structure.
Attention has been shown to modulate the amplitude
of the mismatch negativity (MMN) elicited by a small deviation
in auditory stimuli in adults. The present study examined
the effects of attention and deviant size on MMN amplitude
in children. Children and adults were presented with sequences
of tones containing standards (1000 Hz) and three deviants
varying in degree of deviance from the standard (1050,
1200, and 1500 Hz). Tones were presented in three conditions:
(1) while participants ignored them; (2) while participants
listened to them and responded to all three deviants; and
(3) while participants again ignored them. We found that
the MMNs elicited by the hard deviant (1050 Hz) were larger
when the children were actively discriminating the stimuli
than when they were ignoring them. However, the MMNs elicited
by the easy and medium deviants (1500 and 1200 Hz, respectively)
in the children and by all three deviants in the adults
were not affected by attention.
High resolution neutron diffraction patterns of BaCexZr1−xO3 (x = 0, 0.1, 0.4,
0.8) were obtained at various temperatures. The phase diagram that was deduced from Raman
measurements has been confirmed. Structural transitions occur in a fixed order
c-Pm3m as a function of temperature or composition. For BaCeO3, the
large volume change that has been previously claimed at the Imma-R
c transition has
been revisited and found inconsistent. For a given composition, the cell volume increases
when temperature increases, but the MO6 (M=Ce-Zr) octahedron volume decreases. It is
shown that the ratio of the cell volume to the octahedron volume is a good indicator of the
phase transitions. Transitions occur at fixed values (5.77, 5.80 and 6 for the Pnma-Imma,
c and R
c-Pm3m transitions respectively) independently of
Event-related potentials (ERPs) were recorded during
a go/no-go reaction time (RT) task in which subjects responded
to rare target tones and withheld response to frequent
tones. In a predictable condition, a rare visual stimulus
signalled the impending occurrence of a rare tone, whereas
a frequent visual stimulus signalled that a frequent tone
would be presented. The rare visual stimuli elicited P3,
associated with violations of expectations, whereas the
rare tones, being predictable, did not. The rare tones
elicited the mismatch negativity (MMN), a component associated
with preattentive deviance detection, despite the fact
that they were expected. RT was faster in the predictable
condition than in another condition in which the tones
were not predictable. The P3 and RT data indicate, respectively,
that subjects anticipated and were ready to respond to
the target tones. The MMN result indicates that immediately
before target tones, the preattentive system underlying
the MMN was set for frequent tones, being unaffected by
the information available to the higher order system. Thus,
the higher order cognitive system associated with P3 and
the lower order cognitive system associated with the MMN
were prepared simultaneously for opposite events.
It is not resolved whether the anionic channel involved in volume regulation after cell swelling comprises one or more subunits. Moreover, it remains to be determined which of the different proteins cloned so far, for which an involvement in cell volume regulation has been postulated, is the ideal candidate. In this review, we consider the role of the ICln protein, cloned from MDCK cells, in cell volume regulation.
Fatigue (slow) crack growth in silane bonded epoxy/glass interfaces was studied under static and cyclic loading at 23°C, 95% RH using the double cleavage drilled compression test. Crack growth rates under cyclic loading were significantly greater than under static loading, in contrast to crack growth results in monolithic glass. In addition, cyclic crack growth rate data after aging up to 94°C in distilled water were not significantly different from unaged samples; however, after aging at 98°C in distilled water and 70°C in a KOH aqueous solution of pH 10, crack growth became cohesive and fractal in nature. These results are discussed in terms of possible mechanisms for fatigue crack growth at silane bonded epoxy/glass interfaces.
There is uncertainty concerning the extent to which
the auditory streaming effect is a function of attentive
or preattentive mechanisms. The mismatch negativity (MMN),
which indexes preattentive acoustic processing, was used
to probe whether the segregation associated with the streaming
effect occurs preattentively. In Experiment 1, alternating
high and low tones were presented at fast and slow paces
while subjects ignored the stimuli. At the slow pace, tones
were heard as alternating high and low pitches, and no
MMN was elicited. At the fast pace a streaming effect was
induced and an MMN was observed for the low stream, indicating
a preattentive locus for the streaming effect. The high
deviant did not elicit an MMN. MMNs were obtained to both
the high and low deviants when the interval between the
across-stream deviance was lengthened to more than 250
ms in Experiment 2, indicating that the MMN system is susceptible
to processing constraints.
Electrically switchable volume reflection holograms were written by inhomogeneous illumination of a prepolymer syrup containing a nematic liquid crystal and a multifunctional acrylate monomer. Switchable holograms are diffractive optics structures and the diffraction efficiency can be controlled by the application of an electric field. Reflection gratings with grating spacing varying between 0.16-0.27 µm were made during the phase separation of liquid crystals from the fast curing prepolymer syrup. The reflection efficiency of the holograms were electrically modulated with the applied field of ∼10-15V/µm. Real time study of the grating formation revealed that the maximum efficiency is reached in ∼15 seconds. The shrinkage of the host polymer during grating formation resulted in the blue shift of the reflection notch. The response time of the grating in an electric field is ∼50 µs. Low voltage scanning electron microscope studies showed the presence of discrete nematic droplet domains of sizes 30-60 nm in liquid crystal rich region.
We have determined the process capability of Low Pressure (Rapid Thermal) Chemical Vapor Deposition (LP(RT)CVD) of epitaxial Si/SiGe/Si stacks for heterojunction bipolar transistors (HIBTs). The transistor parameters primarily influenced by the epitaxial characteristics were measured for 600 identically processed 4” wafers. The results demonstrate that it is possible to control accurately the epitaxial process for a 25 nm thick graded SiGe base profile with 20 % Ge and very narrow B doping (5 nm). The pipe limited device yield of about 90 % for an emitter area of 104 μm2 indicates a very low defect density in the epitaxial layer stack. The process capability indices determined from about 40,000 data points demonstrate the stability and capability of the LP(RT)CVD epitaxy with regard to manufacturing requirements.
In strained Sia−xGex heterojunction internal photoemission (HIP) photodiodes the spectral response can be tailored over a wide wavelength range by varying the Ge content. In this paper heavily in situ boron doped SiGe layers with 30% Ge were grown by low pressure rapid thermal chemical vapour deposition (LP(RT)CVD). The detectors exhibit a cut-off wavelength of 8.5 μm. A delta-like P peak, incorporated by atomic layer deposition technique, shifts the cut-off to shorter wavelengths. This shift is related to an increase of the barrier height at the SiGe/Si interface caused by the narrow n+-doped layer in agreement with device simulation. In this way the trade off between critical film thickness for high Ge content film growth and absorption depth for proper detector response can be overcome.
Complete epitaxial Si-SiGe-Si- stacks with a defined doping profile for each component have been deposited on Si substrates from the system SiH4, GeH4, H2, B2H6, PH3 by RTCVD. The deposition has been carried out at a temperature of 650°C for Si and of 500°C for SiGe, respectively, both at a pressure of 2 mbar. The developed epitaxial process including an effective H2 in-situ preclean annealing has been integrated in a simple double mesa technology for the preparation of SiGe base heterojunction bipolar transistors (HBT). Despite the simplicity of the technology and the lithographical level allowing emitter dimensions of 2.3×2.5 μm2 only, test devices on 4” wafers reached transit frequencies fT and maximum oscillation frequencies fmax of higher than 60 GHz and 30 GHz, respectively. Besides, a low base current has been measýnl as proof for a good layer quality.
Chemical Vapor Deposition of Si1-x Gex – films on Si (100) and of polycrystalline Si1-x Gex, layers on SiO2 – coated substrates have been performed at a pressure of 200 Pa in the temperature range of 500°C – 800°C, correspondingly. To observe the growth process and to characterize the growing thin films at deposition conditions an optical reflection interferometer (PYRITIERS) has been used. Comparing the data obtained at growth temperature with ex- situ measurements by spectroscopic ellipsometry the temperature dependence of optical constants of SiGe films have been evaluated. The reflectivity measurements during the deposition process allow to study the quality of the heteroepitaxial film, even in the initial stage of epitaxial growth.
Moisture-assisted crack growth in polymer/glass interfaces was measured as a function of the applied energy release using a four-point flexure test coupled with an inverted microscope. The specimens consisted of two glass plates bonded together with a thin layer of epoxy adhesive. Roughening the surface of one of the interfaces increased its fracture resistance sufficiently so that crack growth on this interface was inhibited. Thus, crack growth would occur only on the “smooth” interface (one with the least fracture resistance) or in the case where both interfaces were smooth, dual cracking occurred. Finite element analysis was used to explain the observed crack growth results.
The paper presented discusses certain topographical effects being significant for the coverage of nonplanar structures with undoped and doped thin SiGe films. They are essential for new integrated heterojunction Si/SiGe devices. To investigate the coverage of topographical surfaces SiGe layers have been deposited on different trench structures in a Rapid Thermal Low Pressure single wafer CVD reactor (RTCVD) from the system SiH4, GeH4, and H2 using B2H6/ H2 and PH3/ H2 for the in-situ doping, respectively. Various deposition conditions and different film compositions have been used. The results especially the differences of the thickness distribution within trenches and on the surface have been discussed with regard to different CVD models taking into account distinguished reaction mechanisms.