Device modeling of HgCdTe vertically integrated photodiodes

Simulations of current-voltage characteristics of ion-implanted n-on-p photodiodes have been performed using SemiCad Device. In order to accurately simulate this device structure, several modifications to the simulator were implemented. These include the modified carrier statistics to account for the nonparabolic band structure of HgCdTe, the correct physics parameters for Shockley-Read-Hall, optical, and Auger recombination, and the Burstein-Moss shift for optical absorption important for heavily doped n-type HgCdTe. With these and other improvements, SemiCad Device is calibrated with the measured ideal dark current of an ion implanted diode and is used to simulate a source of non-ideal dark current from surface-charge induced band-to-band tunneling.     

Tunable infrared absorption and visible transparency of colloidal aluminum-doped zinc oxide nanocrystals

Plasmonic nanocrystals have been attracting a lot of attention both for fundamental studies and different applications, from sensing to imaging and optoelectronic devices. Transparent conductive oxides represent an interesting class of plasmonic materials in addition to metals and vacancy-doped semiconductor quantum dots. Herein, we report a rational synthetic strategy of high-quality colloidal aluminum-doped zinc oxide nanocrystals. The presence of substitutional aluminum in the zinc oxide lattice accompanied by the generation of free electrons is proved for the first time by tunable surface plasmon absorption in the infrared region both in solution and in thin films.     

Haptic interaction of touch and proprioception: implications for neuroprosthetics

Somatosensation is divided into multiple discrete modalities that we think of separably: e.g., tactile, proprioceptive, and temperature sensation. However, in processes such as haptics,those modalities all interact. If one intended to artificially generate a sensation that could be used for stereognosis, for example, it would be crucial to understand these interactions. We are presently examining the relationship between tactile and proprioceptive modalities in this context. In this overview of some of our recent work, we show that signals that would normally be attributed to two of these systems separately, tactile contact and self-movement, interact both perceptually and physiologically in ways that complicate the understanding of haptic processing. In the first study described here, we show that a tactile illusion on the fingertips, the cutaneous rabbit effect, can be abolished by changing the posture of the fingers. We then discuss activity in primary somatosensory cortical neurons illustrating the interrelationship of tactile and postural signals. In this study, we used a robot-enhanced virtual environment to show that many neurons in primary somatosensory cortex with cutaneous receptive fields encode elements both of tactile contact and self-motion. We then show the results of studies examining the structure of the process which extracts the spatial location of the hand from proprioceptive signals. The structure of the spatial errors in these maps indicates that the proprioceptive-spatial map is stable but individually constructed.These seemingly disparate studies lead us to suggest that tactile sensation is encoded in a 2-D map, but one which undergoes continual dynamic modification by an underlying proprioceptive map. Understanding how the disparate signals that comprise the somatosensory system are processed to produce sensation is an important step in realizing the kind of seamless integration aspired to in neuroprosthetics.     

Provider role attitudes, marital satisfaction, role overload, and housework: A dyadic approach.

Treating the marital dyad as the unit of analysis, this study examined the within-couple patterning of 272 dual-earner spouses' provider role attitudes and their longitudinal associations with marital satisfaction, role overload, and the division of housework. Based on the congruence of husbands' and wives' provider role attitudes, couples were classified into one of four types: (a) main-secondary, (b) coprovider, (c) ambivalent coprovider, and (d) mismatched couples. Nearly half of all spouses differed in their attitudes about breadwinning. A series of mixed model ANCOVAs revealed significant between- and within-couple differences in human capital characteristics, spouses' perceptions of marital satisfaction and role overload, and the division of housework across 3 years of measurement. Coprovider couples reported higher levels of marital satisfaction and a more equitable division of housework than the other couple groups. Wives in the ambivalent coprovider couples' group reported higher levels of role overload than their husbands to a greater extent than was found in the other couple groups. As the first study to adopt a dyadic approach that considers the meanings that both spouses in dual-earner couples ascribe to paid employment, these findings advance understanding of how dual-earner spouses' provider role attitudes serve as contexts for marital quality, behavior, and role-related stress. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Characterization of a novel CC chemokine, HCC-4, whose expression is increased by interleukin-10

We have identified and characterized a human beta (CC) chemokine, designated HCC-4, that is most closely related to HCC-1 and which demonstrates chemotactic activity for monocytes. Northern analysis of multiple tissue blots and of activated monocytes mRNA shows expression of a 500-bp mRNA. A 1,500-bp mRNA was highly expressed in monocytes activated 12 hours in the presence of interleukin-10 (IL-10) but was absent in monocytes activated for only 1 hour regardless of the presence or absence of IL-10. The upregulation of expression in the presence of IL-10 is in contrast to the downregulatory effects of IL-10 on expression of most other chemokines. Recombinant HCC-4 demonstrated chemotactic activity for human monocytes and THP-1 monocyte cells but not for resting lymphocytes or neutrophils. HCC-4 also induced a Ca2+ flux in THP-1 cells that was desensitized by prior exposure to RANTES. Taken together, these data indicate that HCC-4 is a novel chemokine whose expression is uniquely upregulated by IL-10.     

32 digital uncompressed TV channel distribution via 8 HDWDMchannels

The performance of a demonstrator for the distribution of 32 digital uncompressed TV channels using HDWDM has been examined. For the transmission 8 optical wavelengths have been used spaced by 2 nm in the 1529-1543 nm range carrying a data rate of 8×622 Mbt/s. Without optical amplifier a splitting factor of 16 has been obtained for the PON with low crosstalk and polarization sensitivities. The demonstrator is the distributive part of a combined demonstrator including broad- and narrowband interactive services     

Surgery of inner ear diseases (author's transl)

In the treatment of Menière's disease, surgical procedures are available when conservative measures have failed. The most distressing symptom of vertigo can frequently be arrested, tinnitus reduced and hearing improved. Sudden deafness due to round window rupture is treatable. The most important disorder with labyrinthe symptoms is the acoustic neuroma, the smaller ones of which can be operated on by otologists in collaboration with neurosurgeons using the transtemporal or translabyrinthine approach with preservation of the facial nerve.     

Digital calibration for monotonic pipelined A/D converters

The original digital calibration approach for 1 b/stage and 1.5 b/stage pipeline analog-digital converters produces missing or nonmonotonic digital codes with the device and circuit impairments typical of modern deep submicrometer CMOS technologies. Two digital calibration algorithms are introduced to improve pipeline performance when using low-voltage low-gain nonlinear operational amplifiers and high random dc offset voltage comparators. The first technique computes calibration coefficients for each stage at actual transition points of the residue characteristic to assure converter monotonicity in the presence of random comparator offset voltages. The second augments a conventional pipelined architecture with an input-dependent level-shifting stage and additional digital calibration circuitry to achieve high differential and integral linearity with low-gain nonlinear operational amplifiers.     

Theoretische und experimentelle Untersuchungen zum Mechanismus des duktilen Bruches metallischer Werkstoffe

Überblick über bekannte Modelle des duktilen Bruches. Begrenzung einer Formänderung durch plastische Instabilität in einem Scherband. Einfluß des Einschlußgehaltes und des Verfestigungsvermögens auf das Formänderungsvermögen. Ermittlung der Verteilung von Einschlüssen. Vergleich des erwarteten Formänderungsvermögens mit Versuchswerten.