Depletion-All-Around Operation of the SOI Four-Gate Transistor

In the silicon-on-insulator four-gate transistors (G⁴-FETs), the conducting channel can be surrounded by depletion regions induced by independent vertical metal-oxide-semiconductor gates and lateral JFET gates. This unique conduction mechanism named depletion-all-around (DAA) enables majority carriers to flow in the volume of the silicon film far from the silicon/oxide interfaces. Especially when the interfaces are driven to inversion, the control of the lateral JFET gates on the conduction is maximized, while the sensitivity of the volume channel to the oxide and interface defects is minimized. This leads to excellent analog performance, low noise, and reduced sensitivity to ionizing radiation. The G⁴-FET properties in DAA mode are presented from multiple perspectives: experimental results, 3-D device simulations, and analytical modeling     

Microstructured Fibers for the Production of Food

Food engineering faces the difficult challenge of combining taste, i.e., tailoring texture and rheology of food matrices with the balanced intake of healthy nutrients. In materials science, fiber suspensions and composites have been developed as a versatile and successful approach to tailor rheology while imparting materials with added functionalities. Structures based on such types of physical (micro)fibers are however rare in food production mainly due to a lack of food‐grade materials and processes allowing for the fabrication of fibers with controlled sizes and microstructures. Here, the controlled fabrication of multi‐material microstructured edible fibers is demonstrated using a food compatible process based on preform‐to‐fiber thermal drawing. It is shown that different material systems based on gelatin or casein, with plasticizers such as glycerol, can be thermally drawn into fibers with various geometries and cross‐sectional structures. It is demonstrated that fibers can exhibit tailored mechanical properties post‐drawing, and can encapsulate nutrients to control their release. The versatility of fiber materials is also exploited to demonstrate the fabrication of food‐grade fabrics and scaffolds for food growth. The end results establish a new field in food production that relies on fiber‐based simple and eco‐friendly processes to realize enjoyable yet healthy and nutritious products.     

Spatial Stress and Strain Distributions of Viscoelastic Layers in Oscillatory Shear

One of the standard experimental probes of a viscoelastic material is to measure the response of a layer trapped between parallel surfaces, imposing either periodic stress or strain at one boundary and measuring the other. The relative phase between stress and strain yields solid-like and liquid-like properties, called the storage and loss moduli, respectively, which are then captured over a range of imposed frequencies. Rarely are the full spatial distributions of shear and normal stresses considered, primarily because they cannot be measured except at boundaries and the information was not deemed of particular interest in theoretical studies. Likewise, strain distributions throughout the layer were traditionally ignored except in a classical protocol of Ferry, Adler and Sawyer, based on snapshots of standing shear waves. Recent investigations of thin lung mucus layers exposed to oscillatory stress (breathing) and strain (coordinated cilia), however, suggest that the wide range of healthy conditions and environmental or disease assaults lead to conditions that are quite disparate from the "surface loading" and "gap loading" conditions that characterize classical rheometers. In this article, we extend our previous linear and nonlinear models of boundary stresses in controlled oscillatory strain to the entire layer. To illustrate non-intuitive heterogeneous responses, we characterize experimental conditions and material parameter ranges where the maximum stresses migrate into the channel interior.     

The Emergence of Clusters in the Global Telecommunications Network

Studies of international telecommunication networks in past years have found increases in density, centralization, and integration. More recent studies, however, have identified trends of decentralization and regionalization. The present research examines these structural changes in international telephone traffic among 110 countries between 1989 and 1999. It examines the competing theoretical models of core–periphery and cluster structures. The initial results show lowered centralization and inequality in the network of international telecommunications traffic. Statistical p * procedures demonstrate significant interactions within countries in blocks of similar economic development status, geographic region, and telecommunications infrastructure development status. Specifically, countries with less developed economic and telecommunications status showed significant increases in tendencies to connect to each other and to reciprocate ties. Altogether, the result supports the idea that the global telecommunications network is moving toward a more diversified structure with the emergence of cohesive and interconnected subgroups. The findings have implications for global digital divide and developmental gap issues.     

Propenoxide isomerization in a fluidized bed reactor

Propenoxide isomerization, over lithium orthophosphate as a catalyst, was investigated in a fluidized bed reactor. A mathematical model of the process was developed and its kinetic parameters identified. There is a high degree of selectivity for allyl alcohol.     

Defect localization induced by hot carrier injection in short-channel MOSFETs: Concept, modeling and characterization

Key aspects related to the localization of the hot-carrier induced damage in short channel MOSFET's are reviewed. Emphasis is put on the analysis, modeling and characterization of the degradation of device parameters caused by defects created locally beside the drain junction. Numerical simulations as well as analytical models predicting the post-stress performance are presented, compared and their limits of validity highlighted. Relevant experimental results, concerning the evolution of the static characteristics I_D(V_G, V_D) during transistor aging, are thoroughly discussed and efficient methods for the extraction of the defective region parameters are proposed. More specific techniques (charge pumping, noise spectroscopy, floating gate current, gated diode leakage), used for the characterization of aging induced defects, are evaluated from the point of view of their capability to cope with the localized nature of the defects. The merits of silicon on insulator structures and other technological solutions proposed for the attenuation of hot carrier effects are briefly commented.     

Extremely low back facet feedback by quantum-confined Stark effectabsorption in an edge-emitting light-emitting diode

The quantum-confined Stark effect is employed to form an integral reverse-biased absorber in a GaInAsP edge-emitting light-emitting diode. Optical low coherence reflectometry is used to measure the magnitude of reflections through this absorber. Front-facet-back-facet roundtrip reflection magnitudes are below -110 dB in devices having an antireflection coating on the front facet only. All other round trip reflections are below -80 dB. This device provides a wide usable dynamic range in optical low coherence reflectometry measurements     

Evanescent amplification in a single-mode optical fibre

By replacing a portion of the cladding of a single-mode fibre with a laser dye, amplification can be achieved by means of an evanescent field interaction. External gains as high as 22 dB have been measured by guiding both a pulsed pump and CW signal within the single-mode fibre.