Frequency dispersion reduction and bond conversion on n-type GaAs by in situ surface oxide removal and passivation

The method of surface preparation on n-type GaAs, even with the presence of an amorphous-Si interfacial passivation layer, is shown to be a critical step in the removal of accumulation capacitance frequency dispersion. In situ deposition and analysis techniques were used to study different surface preparations, including NH4OH, Si-flux, and atomic hydrogen exposures, as well as Si passivation depositions prior to in situ atomic layer deposition of Al2O3. As–O bonding was removed and a bond conversion process with Si deposition is observed. The accumulation capacitance frequency dispersion was removed only when a Si interlayer and a specific surface clean were combined

Words fail me: the verbal IQ deficit in inflammatory bowel disease and irritable bowel syndrome

Background: Many chronic illnesses are accompanied by impaired cognitive functioning. In people with Inflammatory Bowel Disease (IBD), there is some research to suggest a decrement in verbal IQ (VIQ), when compared to people with Irritable Bowel Syndrome (IBS) and healthy controls. Although this is an important finding, it is necessary to ensure that such deficits are not due to methodological problems such as the failure to take into account pre-morbid functioning. Methods: A total of 88 people (IBD, N 29; IBS, N 29; Controls, N 30) completed the Wechsler Abbreviated Scale of Intelligence (WASI), the Wechsler Test of Adult Reading (WATR), the Trait Rumination Questionnaire (TRQ), the Center for Epidemiologic Studies Depression Scale (CES-D), and the General Health Questionnaire (GHQ-12). Results: We found evidence of a VIQ decrement in both IBD and IBS groups when measured against both healthy controls and against their own pre-morbid IQ scores (WTAR-Predicted WAIS-III IQ measures). However, the decrement was larger (and of clinical significance) in the IBD group but not in the IBS group. Conclusion: Some tentative evidence is presented which suggests that poor VIQ performance may be due in part to interference from excessive rumination

GaAs interfacial self-cleaning by atomic layer deposition

The reduction and removal of surface oxides from GaAs substrates by atomic layer deposition (ALD) of Al2O3 and HfO2 are studied using in situ monochromatic x-ray photoelectron spectroscopy. Using the combination of in situ deposition and analysis techniques, the interfacial "self-cleaning" is shown to be oxidation state dependent as well as metal organic precursor dependent. Thermodynamics, charge balance, and oxygen coordination drive the removal of certain species of surface oxides while allowing others to remain. These factors suggest proper selection of surface treatments and ALD precursors can result in selective interfacial bonding arrangements

Italia. 1:2666667

Indica meridiano de París ; Márgenes graduados.Indica: Relieve sombreado ; Cables submarinos.Incluye leyenda de signos utilizados

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Indica meridiano de París ; Márgenes graduados.Indica relieve: sombreadoIncluye leyenda de signos utilizados

EUROPA. E. Geografía militar (1880). 1:3773585

Indica meridiano de París ; Márgenes graduados ; Relieve.Inserta : 'Complement pour la Bosnie'.Indica leyenda de signos utilizados

EUROPA. NE. Geografía militar (1880). 1:3703704

Indica meridiano de París ; Márgenes graduados.Incluye leyenda de signos utilizados.Con: Carte de raccord entre l'Allemagne et l'Italie peninsulair

Hydrodynamics of topological defects in nematic liquid crystals

We show that back-flow, the coupling between the order parameter and the velocity fields, has a significant effect on the motion of defects in nematic liquid crystals. In particular the defect speed can depend strongly on the topological strength in two dimensions and on the sense of rotation of the director about the core in three dimensions.Comment: 4 pages including two figure

Defect structures and torque on an elongated colloidal particle immersed in a liquid crystal host

Combining molecular dynamics and Monte Carlo simulation we study defect structures around an elongated colloidal particle embedded in a nematic liquid crystal host. By studying nematic ordering near the particle and the disclination core region we are able to examine the defect core structure and the difference between two simulation techniques. In addition, we also study the torque on a particle tilted with respect to the director, and modification of this torque when the particle is close to the cell wall

On the calculation of effective electric field in In0.53Ga0.47As surface channel metal-oxide-semiconductor field-effect-transistors

The effective electron mobility of In0.53Ga0.47As metal-oxide-semiconductor field-effect-transistors with HfO2 gate oxide was measured over a wide range of channel doping concentration. The back bias dependence of effective electron mobility was used to correctly calculate the vertical effective electric field. The effective electron mobility at moderate to high vertical effective electric field shows universal behavior independent of substrate impurity concentration. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3588255