Microrheology as a tool for high-throughput screening

Microrheology can be used for high-throughput screening of the rheological properties of sample libraries of complex fluids. Two passive techniques are particularly suitable: video microscopy and diffusing-wave spectroscopy. The techniques complement each other very well and can be applied to samples that offer different experimental challenges. We offer a thorough analysis of the strengths and limitations of microrheology with the emphasis on high-throughput applications. To illustrate the potential of microrheology, results are presented for two representative cases: the rheological screening of aqueous solutions of a block copolypeptide library and the rheological phase diagram of a water/surfactant/salt system.     

Distance spectrum analysis of space-time trellis-coded Modulations in quasi-static Rayleigh-fading channels

In this correspondence, we propose an algorithm for computing the distance spectrum of a space-time trellis code achieving maximal diversity gain in quasi-static fading channels. We further present a state reduction technique for trellis codes that can reduce the complexity of the distance spectrum computation. We provide numerical results supporting the empirical evidence that a truncated union bound obtained from the distance spectrum provides an accurate characterization of the relative performance ordering of different space-time trellis codes and, therefore, it offers a tool for better space-time trellis code design.     

Study of internal behavior in a vertical DMOS transistor under short high current stress by an interferometric mapping method

Current distribution in vertical double-diffused MOS (DMOS) transistors of a Smart Power Technology are investigated under high current, short duration operation conditions by means of a backside laser interferometric thermal mapping technique. DMOS devices of different areas are studied under pulsed gate forward operation mode and under electrostatic discharge (ESD)-like stress with floating and grounded gate. The internal behavior of the devices observed by thermal mapping under these stress conditions is correlated with the electrical characteristics.     

Pile Response Adjacent to Braced Excavation

The excavation of soil for the construction of basements or cut-and-cover tunnels results in ground movements. One particular concern is that the excavation-induced lateral soil movements may adversely affect any nearby pile foundation. The lateral loads imposed by the soil movements induce bending moments and deflections in the pile, which may lead to structural distress and failure. This paper presents the results of an actual full-scale instrumented study that was carried to examine the behavior of an existing pile due to nearby excavation activities resulting from the construction of a 16 m deep cut-and-cover tunnel. The pile was located 3 m behind a 0.8 m thick diaphragm wall. Excavation to the formation level that was 16 m below the ground surface resulted in a maximum lateral pile movement of 28 mm. A simplified numerical procedure based on the finite-element method was used to analyze the pile response. Generally, the theoretical predictions were in reasonable agreement with the measured results.     

Editorial: Final Thoughts and the Passing of the Editorial Mantle.

The retiring editor of the Journal of Family Psychology (1997-2003) offers final thoughts on the passing on of the editorship and extends thanks to journal associates. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

RbCl:Li color center laser with laser diode pumping

CW operation of a RbCl:Li-F_A(II) laser has been obtained under pumping by a red laser diode. Pump power at threshold is 90 mW. Single frequency operation of the color center laser has been achieved. The intensity noise generated by two pump sources (laser diode and Kr-ion laser) is compared     

Structure determination of CaMgGeO4

The crystal structure of CaMgGeO₄ is described. CaMgGeO₄, M_r = 200.9, orthorhombic, Pnam, A = 11.285(5) Å, B = 5.016(2) Å, C = 6.435(2) Å, V = 364.36 ų, Dx = 3.664 Mg/m³.λ(MoK_a = 0.71069 Å, F(000) = 384, room temperature, final R = 0.045 for 1752 observed reflections. The structure is isomorphous with CaMgSiO₄ (monticellite).     

Effect of exponentially graded base doping on the performance ofGaAs/AlGaAs heterojunction bipolar transistors

The authors have fabricated n-p-n GaAs/AlGaAs heterojunction bipolar transistors (HBTs) with base doping graded exponentially from 5×10¹⁹ cm^-3 at the emitter edge to 5×10¹⁸ cm^-3 at the collector edge. The built-in field due to the exponentially graded doping profile significantly reduces base transit time, despite bandgap narrowing associated with high base doping. Compared to devices with the same base thickness and uniform base doping of 1×10¹⁹ cm^-3 , the cutoff frequency is increased from 22 to 31 GHz and maximum frequency of oscillation is increased from 40 to 58 GHz. Exponentially graded base doping also results ill consistently higher common-emitter current gain than uniform base doping, even though the Gummel number is twice as high and the base resistance is reduced by 40%     

Cyclostationary crosstalk suppression by decision feedbackequalization on digital subscriber loops

Interference from digital signals in multipair cables has been shown to be cyclostationary under some conditions. This work evaluates the performance of a decision feedback equalizer (DFE) in the presence of cyclostationary interference (CI), intersymbol interference (ISI), and additive white noise (AWN). A comparison between a DFE with CI and one with stationary interference (SI) shows the ability of the DFE to substantially suppress CI. Fractionally spaced and symbol-rate DFE equalizers are also compared and the former is found to yield better performance, especially in the presence of CI. The use of a symbol-rate DFE using an adaptive timing technique that finds the receiver's best sampling phase is proposed for when the fractionally spaced DFE cannot be used because of its complexity. The results also demonstrate the potential benefits of synchronizing central office transmitter clocks, if a fractionally spaced DFE is used at the receiver