Thermal Isolation of Encapsulated MEMS Resonators

This paper presents an in-chip thermal-isolation technique for a micro-ovenized microelectromechanical-system resonator. Resonators with a microoven can be used for high-precision feedback control of temperature to compensate for the temperature dependence of resonator frequency over a wide temperature range. However, ovenization requires power consumption for heating, and the thermal time constant must be minimized for effective temperature control. This paper demonstrates an efficient local-thermal-isolation mechanism, which can reduce the power requirement to a few milliwatts and the thermal time constant to a few milliseconds. In this method, the mechanical suspension of the resonator is modified to provide thermal isolation and include an integrated resistive heater. This combination provides mechanical suspension, electrical heating, and thermal isolation in a compact structure that requires low heating power and has a small thermal time constant. A power consumption of approximately 12 mW for a 125degC temperature rise and a thermal time constant ranging from 7 to 10 ms is reported in this paper, which is orders of magnitude lower than that of commercially available ovenized quartz resonators. A CMOS-compatible wafer-scale encapsulation process is used to fabricate this device, and the thermal-isolation design is achieved without any modification to the existing resonator fabrication process.     

Rectangular mode transformers in tapered single-mode fibres

A single-mode fibre, polished on both sides and subsequently tapered, yields a low-loss circular-to-rectangular mode transformer. This device should permit more efficient interconnection of circular fibres to rectangular integrated-optic and semiconductor waveguides.<>     

Elastohydrodynamic properties of water-based fire-resistant hydraulic fluids

The elastohydrodynamic (ehd) lubricating properties of commercial fire-resistant hydraulic fluids in rolling point contacts are described. Earlier work is reviewed and new work presented on water-in-oil and oil-in-water emulsions. It is shown that in general, elastohydrodynamic film thicknesses of water-in-oil emulsions are close to those of their base oils. For very fine particle size emulsions, however, thicker films are observed. Commercial oil-in-water emulsions in fully flooded conditions have not been found to give measurable elastohydrodynamic films. However, when the emulsions are destabilized, a localized pool of oil collects in the contact zone which enables ehd films to form, though these films do not survive very high rolling speeds. Polyglycol solutions give low ehd film thicknesses, approximately one third those of mineral oils of corresponding viscosity. This can be attributed to the low pressure—viscosity coefficient of these solutions.     

Separating individual and group effects.

Presents a new multivariate statistical technique that includes both individual and group effects and allows for nonindependence between group members in hierarchically nested designs in small-group research. In the present statistical technique, the estimated correlation matrices for the individual and for the group can be used as input into multivariate procedures (e.g., multiple regression, factor analysis). The application of the technique is illustrated for data on crowding in university residential environments. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dendritic cell-based immunotherapy of prostate cancer

The protective effect of catechins, major components of green tea, was studied in cultured human umbilical vein endothelial cells exposed to toxicity induced by linoleic acid hydroperoxide (LOOH). In the case where cells were incubated in medium containing both LOOH and catechins, (+)-catechin (C) was effective in suppressing of LOOH-induced cytotoxicity, but (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epicatechin gallate (ECG), and (-)-epigallocatechin gallate (EGCG) had no effect. EGCG monoglucoside (EGCG-G1) and EGCG diglucoside (EGCG-G2), apophilic derivatives of EGCG, show a protective effect on LOOH-induced cytotoxicity when present at the time of treatment with LOOH. On the other hand, when cells were incubated with catechins for 24 h before treatment with LOOH there was no protection against the oxidative damage by LOOH. Furthermore, the interaction between catechins and alpha-tocopherol was examined under these culture conditions. C showed a synergistic effect with alpha-tocopherol in protecting against LOOH-induced damage. These results suggest that catechins interact with LOOH present in the medium or near the surface of membranes, but not with LOOH incorporated into cellular membranes and that catechins are able to interact with alpha-tocopherol to provide synergistic protection against the cytotoxicity of LOOH.     

The efficacy of the Canter Background Interference Procedure in identifying children with cerebral dysfunction.

Compared the Canter Background Interference Procedure (BIP) for the Bender-Gestalt Test using 3 groups of 8-12 yr olds: a cerebral dysfunction (n = 66), an emotionally disturbed (n = 39), and a control (n = 63) group. Ss with cerebral dysfunction performed more poorly on the Bender itself and both scores deteriorated more on the BIP than did those of Ss in the other 2 groups. The emotionally disturbed and control groups did not differ. Applications of the BIP to the detection of cerebral dysfunction in children is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Processing inconsistent social information.

Evidence suggests that expectations can influence the reporting of social events. The present research examined whether social information consistent with expectations is rated more accurately than information inconsistent with expectations and, further, whether such a bias arises during the initial encoding of material or during later stages of a rating task. 64 undergraduates in each of 2 experiments were presented with the traits of a group of individuals, and later they were asked to report this information on simulated rating forms. Analyses indicated that trait information consistent with expectations was rated more accurately and remembered better than information inconsistent with expectations. Expectations not only influenced the initial encoding of the trait material but also appeared to have an effect during later stages of the rating process. Beyond their theoretical significance, the findings have implications for the use of observer ratings in social science research. (44 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Splitting the reciprocity correlation.

Reciprocity of attraction has been called a fundamental principle of social relations. However, correlational data provide only meager support for actual reciprocity. A formal analysis reveals that the reciprocity correlation contains a mixture of 2 correlations: reciprocity at the individual and at the dyadic level. These 2 correlations can be estimated from a round robin design. Data from 48 college students and 336 dyads, measured at 5 time points, showed a –.210 individual level correlation and a .617 dyadic level correlation. The necessity for an appropriate design, specification of a theoretical and statistical model that includes 2 levels of analysis, and use of an indirect estimation procedure to calculate the model parameters are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)