Investigation of amorphous Ni0.60Nb0.40 diffusion barriers

Interactions of Ni_0.60Nb_0.40 amorphous alloys with polycrystalline overlayers of gold and copper and single-crystal substrates of silicon. GaAs and GaP were observed with Auger depth profiling. The Ni-Nb layer was deposited by r.f. sputtering and was approximately 5000 Å thick. The overlayers were evaporated to a thickness of 1000 Å. The amorphous metal reacted with the gold overlayers and the GaAs and GaP substrates at temperatures well below the nominal crystallization temperature of 650 °C. The Cu/Ni-Nb/Si system, in contrast, was stable at 600 °C for at least 1 h. Samples were also measured that had been contaminated with approximately 5–10 at.% O. Complete separation of the niobium and nickel into distinct layers was seen. For the samples on silicon substrates this separation was accompanied by the formation of a nickel silicide layer.     

Implantable biomedical microsystems for neural prostheses.

In the following article, the technologies to fabricate polyimide-based thin and flexible substrates with monolithically integrated electrode arrays and printed circuit boards (PCB) for hybrid electronic assemblies as well as an assembling technique that connects bare electronic dice with flexible PCBs are presented. The concept of modular, flexible biomedical microsystems as neural prostheses is introduced in general and described in detail in three examples. A cuff electrode with integrated multiplexer circuitry and standard implantable cables represents the combination of microtechnology with precision mechanics; a sieve electrode used as an implant in peripheral nerve regeneration studies demonstrates the next level of integration density but still uses a cable connection; and last, joint effort to fabricate the demonstrator of a vision prosthesis that is completely implantable in the eye with a wireless link for energy supply and data transmission is presented. System design, hybrid assembling technology, and flexible multilayer encapsulation using parylene and silicone rubber are the key components for creating a new generation of neural prostheses for complex and challenging new applications.     

Ground state systematics and collective dipole excitations of spheroidally deformed sodium clusters in a diffuse jellium model

We solve the Kohn-Sham equations self-consistently in the local density approximation for spheroidal sodium clusters in the particle range 8 ≤ Z ≤ 40. We use a smooth fermi-like jellium density to simulate the influence of the ions in the surface region and obtain similar results as Ekardt and Penzar, but slightly different regions of prolate-to-oblate transitions. We present the systematics of potential energy curves with respect to transitions between oblate, prolate and spherical shapes. Shape transitions occur at particle numbers 12/14 (prolate/oblate), 18/20/22 (oblate/spherical/prolate) and 30/32 (prolate/oblate), which are in good agreement with experimental results. The quadrupole and hexadecupole overlap of the electron density with the jellium is investigated, showing a strong hexadecupole dependence for selected clusters. Collective dipole resonances are described in a simple sum rule approach, which reveals a double splitting according to the different resonance frequencies along the principal axes of the spheroid. The systematics of the resonance peaks for the larger clusters with Z ≥ 20 is in good agreement with experimental results.     

Psychological adjustment of children with sickle cell disease: Stability and change over a 10-month period.

Rates of poor psychological adjustment of children with sickle cell disease remained relatively constant over initial and follow-up assessment points. 50 children (aged 7–12 yrs) and their mothers completed the initial protocol. 30 children completed the follow-up plus 5 additional children and their mothers. These Ss were aged 7–24 yrs at follow-up. With initial levels of adjustment controlled, children's strategies for coping with pain accounted for a significant increment in child-reported symptoms and mother-reported internalizing behavior problems at follow-up beyond the contribution of illness and demographic parameters and follow-up interval. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Enhancing the brightness of thin-film electroluminescent displaysby improving the emission process

AC thin film electroluminescent (ACTFEL) devices emit light laterally in addition to conventional surface emission. Because of the waveguiding in ACTFEL devices, lateral emission is stronger than surface emission. However, the former is ignored for displays. This note demonstrates that mirrors can be fabricated into substrates to reflect upward the lateral emission, which can then be summed with surface emission for displays. Use of standard silicon and thin film technology has demonstrated that the reflected lateral emission is a factor of three brighter than conventional surface emission. hence the effective efficiency of out-coupling the light has been improved for an ACTFEL device     

Spatiotemporal boundary formation: Boundary, form, and motion perception from transformations of surface elements.

Continuous surface boundaries, object shape, and global motion can be perceived from information that is fragmentary in both space and time. The authors report investigations indicating that accretion and deletion of texture is only 1 member of a broader class of element transformations that produce boundaries, shape, and motion, through spatiotemporal boundary formation (SBF). Four experiments exploring SBF are reported. The 1st 3 examine the class of transformations producing SBF, indicating that local element changes in color, orientation, or location are all effective. A 4th experiment examines temporal constraints on SBF. Integration of local element changes to produce boundaries, form, and global motion appears to be confined to a 165-msec window. Two classes of spatiotemporal integration models are considered; the relation between SBF and other cases of boundary interpolation are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Verbesserung des Vakuums in Isoliergefäßen aus Glas

Improving the vacuum would increase the insulation capacity of commercially available glass containers by a factor of about two. To do this, pressures of 10^?4 mbar must be attained. Different approaches were taken to meet this objective. As an alternative to today's commonly practiced sealing method, three possibilities are introduced which eliminate the necessity of pump stub narrowing which causes reduced conductance. Furthermore, depending on the sealing process used, the gases occuring during sealing are either avoided completly or they can at least be reduced by having the chance of exact temperature control resp. by a lower separation temperature. A completly different approach was taken by using Getters, of which a metal hydride on a TiVMn base proved especially suitable. It is activated by heat and can be integrated into the normal production process without any problem. Aside from a shorter pump period, the added advantage here is the containment of the gasses occuring during sealing as well as that of the longterm gasses.     

Erythrocyte sodium lithium countertransport in normal and hypertensive pregnancy: relation to haemodynamic changes

OBJECTIVE: To establish the changes in erythrocyte sodium lithium countertransport (SLC) with advancing normal pregnancy and to determine if these changes were different in pregnancy induced hypertension (PIH). The changes in both groups were assessed in relation to haemodynamic changes. DESIGN: SLC, mean arterial pressure (MAP), cardiac output (CO) and total peripheral vascular resistance (TPVR) were determined serially during normal pregnancy and cross-sectionally in PIH. Women were studied again 20 weeks after delivery where possible. SETTING: Routine antenatal clinic and antenatal ward of a regional reference centre. SUBJECTS: Fifty-one normal primigravid women were studied serially and 41 primigravid women with PIH were studied at time of diagnosis. RESULTS: During normal pregnancy SLC (mmol Li/h/l cells) increased from a nonpregnant value of 0.24 +/- 0.02 (mean +/- SEM) to 0.32 +/- 0.02 at 14 weeks, and 0.37 +/- 0.02 at 20 weeks gestation. This was maintained until 38 weeks (0.40 +/- 0.02). The increase until 20 weeks occurred at the time of greatest change in CO (5.10 +/- 0.18 to 6.79 +/- 0.20 l/min) and TPVR (1327 +/- 58 to 969 +/- 33 dyn/s/cm-5). The decrease in TPVR with a rise in SLC is opposite to the relation reported in essential hypertension so that a functional relation is unlikely. However, the changes within pregnancy were positively correlated (r = 0.43, P < 0.01). In hypertensive pregnancies TPVR was elevated compared with normotensive pregnancies (1543 +/- 100 vs 1090 +/- 37) but the SLC was not different from that found in normotensive pregnancies (0.43 +/- 0.02 vs 0.40 +/- 0.02). CONCLUSIONS: The changes in SLC activity suggest dynamic effects on erythrocyte membrane function during pregnancy. However, no differences could be found between normal and hypertensive pregnancy and SLC is unlikely to be of value as a marker of hypertensive risk during pregnancy.