Interface engineering of short-period Ni/V multilayer X-ray mirrors

Low-energy ion-assisted magnetron sputter deposition has been used for the synthesis of highly reflective Ni/V multilayer soft X-ray mirrors. A low ion energy and a high ion-to-metal flux ratio were employed in order to stimulate the adatom mobility while minimizing ion-induced intermixing at the interfaces. An analytic model, based on the binary collision approximation, was used in order to gain insight into low-energy ion–surface interactions as a function of ion energy and ion-to-metal flux ratio. The model predicted a favorable region in the ion energy-flux parameter space where only surface atomic displacements are stimulated during growth of Ni and V for multilayers. For a series of Ni/V multilayer mirrors with multilayer periods about Λ = 1.2 nm, grown with a continuous ion assistance using energies in the range 7–36 eV and with ion-to-metal flux ratios Φ_Ni = 4.7 and Φ_V=20.9, specular and diffuse X-ray scattering analyses revealed that ion energies of 27–31 eV produced the best trade-off between reduced interfacial roughness and intermixing. However, it was also concluded that an interface mixing of about ± 1 atomic distance is unavoidable when a continuous flux of assisting ions is used.

To overcome this limitation, a sophisticated interface engineering technique was employed, where the first 0.3 nm of each layer was grown with a high-flux low-energy ion assistance and the remaining part was grown with a slightly higher ion energy. This method was demonstrated to largely eliminate the intermixing while maintaining the smoothening effect of ion assistance. Two Ni/V multilayer soft X-ray mirror structures, one with 500 periods designed for near-normal incidence and one 150 periods reflecting polarizer at the Brewster angle, were grown utilizing the interface engineering concept. Both the near-normal incidence reflectivity as well as polarizability were improved by a factor of 2 as compared to previously reported data for an X-ray energy of E = 511 eV.     

Mobile Network Evolution – “The Return of the Pipe”

The mobile network evolution from second generation to third generation systems has opened possibilities for inclusion of new technologies both in the network infrastructure as well as on the radio access. Within this paper, we concentrate on the evolution of the network infrastructure towards a future mobile network that balances the demand for increased flexibility with the necessity of limiting system complexity. Based on existing architectures, to lower complexity such as layered architecture for the core network and mobile packet backbone, we describe one possible evolution path for the control layer. Our approach is a step towards a control space that includes packetpipe control functions for a multitude of packetpipes. Such control function needs to be supported in the heterogeneous networks of today and the future.     

Autosomal dominant medullary cystic kidney disease: evidence of gene locus heterogeneity

Autosomal dominant medullary cystic kidney disease (ADMCKD; synonym: medullary cystic disease, MCD) is an autosomal dominant kidney disorder, sharing morphological and clinical features with recessive juvenile nephronophthisis (NPH), such as reduced urinary concentration ability and multiple renal cysts at the corticomedullary junction. While in NPH end-stage renal disease (ESRD) occurs in adolescence, ADMCKD leads to ESRD in adulthood. Recently a gene locus for ADMCKD has been localized to chromosome 1q21 in two large Cypriot families. This prompted us to examine linkage in three ADMCKD-families, using the same set of polymorphic microsatellite markers spanning the critical region on chromosome 1q21. Haplotype analysis revealed that none of the three families showed linkage to this locus, thus demonstrating evidence for genetic locus heterogeneity. Additional linkage analysis studies need to be performed in order to identify further gene loci cosegregating with this autosomal dominant kidney disorder.     

Human submandibular saliva aggregates HIV

Incubation of HIV with human whole, parotid, or submandibular saliva leads to a decrease in viral infectivity in Sup-T1 cells. The effect is most pronounced with submandibular saliva. Inhibition is seen within 2 min, and increases with time. There is little inhibition seen after incubation of saliva with HSV, and no effect with adenovirus, suggested that there is some viral specificity. Electron microscopic studies revealed that HIV-saliva aggregates are trapped in 0.45-microns pore size nitrocellulose filters. If these inhibitory effects are manifest in vivo, this could account for the low level of virus detected in oral secretions.     

Changes in descending pain threshold related to rate of noxious stimulation.

Measured detection threshold, pain threshold, and pain tolerance for electrical stimulation in 20 healthy male volunteer medical students, using the psychophysical method of limits. The ascending rate of stimulation was held constant, but 5 different descending rates were employed. The descending pain threshold decreased significantly with increases in the descending speed of stimulation, but all other response parameters remained constant. It is proposed that several factors, including adaptation to pain and emotional reactivity associated with relief of pain, caused these results. Simple reaction time was excluded as a significant variable. It is suggested that descending pain parameters require more systematic study, especially since the relief of suffering may be more closely related to clinical pain than experimentally-induced ascending pain parameters. (21 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Factor analysis of human pain responses: Pain endurance as a specific pain factor.

Induced cutaneous and deep somatic pain with chemical, electrical, and thermal noxious stimuli in 60 18-69 yr. Old chronic arthritis patients. Pain threshold, pain tolerance, and pain sensitivity range (psr) were measured psychophysically and correlated within and between techniques. The correlations were subjected to the centroid method of factor analysis and the 1st 4 factors extracted and rotated to a simple structure criterion. The 1st factor was identified as a cutaneous and the 2nd and 4th as gluteal sensitivity factors, but the 3rd appeared to be a specific pain factor, termed pain endurance, most highly loaded with psrs from different techniques and body loci. This pain factor was related to successful postoperative outcome of painful rehabilitation in the ss. (29 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of heat transfer on the development of residual stresses in quenched steel cylinders

In this paper results of systematic FE-calculations about the influence of characteristic points of the temperature dependent heat transfer coefficient, especially the Leidenfrost point and the point of maximum heat transfer coefficient on the development of residual stresses are discussed. The numerical investigations were carried out for SAE 1045 and 4140 steel cylinders with 10 and 20 mm 0 quenched in water and oil, respectively. In this work experimentally determined h, T-curves are linearly approximated in the successive stages of heat transfer. Changes of the Leidenfrost-temperature do not influence the middle plane residual stresses of the cylinders investigated. Increasing maximum heat transfer coefficients and low temperatures of maximum heat transfer coefficient, respectively, cause higher magnitudes of residual stress. The development of residual stresses is determined by the temperature dependent gradient of the heat flux density δq/δT in the temperature range of martensitic transformation. Increasing Leidenfrost-temperatures cause more homogeneous stress and residual stress states at the surface of quenched cylinders due to the symmetrical cooling of the sample in axial as well as in radial direction. In particular, it was shown that during immersion cooling of cylindrical parts the heat transfer is locally dependent. Simulating immersion cooling this dependence has to be considered using effective local heat transfer coefficients.     

Untersuchungen zum Anschlagtiefziehen von vergütetem Stahlblech

Versuche zum Anschlagtiefziehen runder zylindrischer Teile mit einem vergütbaren Stahlband bei unterschiedlich hoher Vergütung. Ermittlung der maximalen Ziehkräfte und Grenzziehverhältnisse. Methode zur näherungsweisen Berechnung der maximalen Ziehkraft. Beurteilung und Eigenschaften der tiefgezogenen Näpfe.