Drain Voltage Scaling in Carbon Nanotube Transistors

While decreasing the oxide thickness in carbon nanotube field-effect transistors (CNFETs) improves the turn-on behavior, we demonstrate that this also requires scaling the range of the drain voltage. This scaling is needed to avoid an exponential increase in Off-current with drain voltage, due to modulation of the Schottky barriers at both the source and drain contact. We illustrate this with results for bottom-gated ambipolar CNFETs with oxides of 2 and 5 nm, and give an explicit scaling rule for the drain voltage. Above the drain voltage limit, the Off-current becomes large and has equal electron and hole contributions. This allows the recently reported light emission from appropriately biased CNFETs.Comment: 4 pages, 4 EPS figure, to appear in Appl. Phys. Lett. (issue of 15 Sept 2003

Electronic Devices Based on Purified Carbon Nanotubes Grown By High Pressure Decomposition of Carbon Monoxide

The excellent properties of transistors, wires, and sensors made from single-walled carbon nanotubes (SWNTs) make them promising candidates for use in advanced nanoelectronic systems. Gas-phase growth procedures such as the high pressure decomposition of carbon monoxide (HiPCO) method yield large quantities of small diameter semiconducting SWNTs, which are ideal for use in nanoelectronic circuits. As-grown HiPCO material, however, commonly contains a large fraction of carbonaceous impurities that degrade properties of SWNT devices. Here we demonstrate a purification, deposition, and fabrication process that yields devices consisting of metallic and semiconducting nanotubes with electronic characteristics vastly superior to those of circuits made from raw HiPCO. Source-drain current measurements on the circuits as a function of temperature and backgate voltage are used to quantify the energy gap of semiconducting nanotubes in a field effect transistor geometry. This work demonstrates significant progress towards the goal of producing complex integrated circuits from bulk-grown SWNT material.Comment: 6 pages, 4 figures, to appear in Nature Material

Synthesis and characterisation of new Bi(iii)-containing apatite-type oxide ion conductors: the influence of lone pairs

Lone-pair cations are known to enhance oxide ion conductivity in fluorite- and Aurivillius-type materials. Among the apatite-type phases, the opposite trend is found for the more widely studied silicate oxide ion conductors, which exhibit a dramatic decrease in conductivity on Bi(III) incorporation. In this work, the influence of lone-pair cations on the properties of apatite-type germanate oxide ion conductors has been investigated by preparing and characterising seven related compositions with varying Bi(III) content, by X-ray and neutron powder diffraction and impedance spectroscopy. All materials are very good oxide ion conductors (with conductivities of up to 1.29 × 10−2 S cm−1 at 775 °C). Increasing Bi(III) content leads to increases in conductivity by up to an order of magnitude, suggesting significant differences in the oxide-ion conduction mechanisms between lone-pair-containing apatite-type germanate and silicate solid electrolytes

Use of Probiotics as Growth Promoters and Immunostimulators in Fingerlings of Cyprinid Fish Species

Intensive aquaculture production has required the development of an individual’s resistance to disease rather than depending upon antibiotics or chemotherapeutics. The role of gastrointestinal microflora in disease resistance has been established in many fish species, which has led to the concept of manipulating gastrointestinal microflora for better health management. A number of studies has been conducted in different fish species with various useful microorganisms called ‘probiotics’ to amplify gastrointestinal microflora to fight against various infectious diseases. Probiotics are beneficial microorganisms which protect the host from diseases. Probiotic protection can be achieved by various mechanisms. Most probiotics used in aquaculture belong to the lactic acid bacteria, the genus Bacillus, the photosynthetic bacteria, the yeast, notwithstanding other genera and species have also been used. The immunostimulatory effect of probiotics has been established in many fish species, but their direct involvement in the immune response is not well established. It has also been proven that the application of probiotics in aquaculture has beneficial effects on growth of fish as well as on the environment. At present, data about the efficacy of probiotics in commercial aquaculture of Serbia is still lacking. This review discusses mainly the studies and applications about effects, problems and perspectives of probiotics used in fingerlings of cyprinid fish species, and highlights immunostimulatory effects and growth promotion effects of commercial probiotic products. In the present paper the results that show positive influence of probiotics in cyprinides nutrition on production performance and immune system are summarized. Special accent is given to criteria for proper selection of probiotics in cyprinides production

Carbon nanotube composites for thermal management

Single-wall carbon nanotubes (SWNTs) were used to augment the thermal transport properties of industrial epoxy. Samples loaded with 1 wt% unpurified SWNT material show a 70% increase in thermal conductivity at 40K, rising to 125% at room temperature; the enhancement due to 1 wt% loading of vapor grown carbon fibers is three times smaller. Electrical conductivity data show a percolation threshold between 0.1 and 0.2 wt% SWNT loading. The Vickers hardness rises monotonically with SWNT loading up to a factor of 3.5 at 2 wt%. These results suggest that the thermal and mechanical properties of SWNT-epoxy composites are improved, without the need to chemically functionalize the nanotubes

COMPENSATION OF INFLUENCE OF PROTECTOR COMPRESSION COEFFICIENTS IN TYRE INDUSTRY

The system for protector cooling (protective rubber strip) in the tyre industry is presented in this paper. The analysis of compensation of protector compression coefficients influence on the protector length change between two neighbor transporters is done. Also, the compensation of protector compression coefficients influence on all transporters velocities is analyzed. Modelling and simulation of transportation system is performed in Matlab/Simulink

The Non-Steroidal FXR Agonist Cilofexor Improves Portal Hypertension and Reduces Hepatic Fibrosis in a Rat NASH Model

Background: The farnesoid X receptor (FXR) influences hepatic metabolism, inflammation and liver fibrosis as key components of non-alcoholic steatohepatitis (NASH). We studied the effects of the non-steroidal FXR agonist cilofexor (formerly GS-9674) on portal pressure and fibrosis in experimental NASH. Methods: NASH was induced in Wistar rats using a choline-deficient high-fat diet plus intraperitoneal sodium nitrite injections. First, a dose-finding study was performed with 10 mg/kg and 30 mg/kg of cilofexor, focusing on histological readouts. Liver fibrosis was assessed by Picro-Sirius-Red, desmin staining and hepatic hydroxyproline content. Gene expression was determined by RT-PCR. In a subsequent hemodynamic study, rats received 30 mg/kg cilofexor with or without propranolol (25 mg/kg). Portal pressure, systemic hemodynamics and splanchnic blood flow were measured. Results: Cilofexor dose-dependently induced FXR target genes shp, cyp7a1 and fgf15 in hepatic and ileal tissues, paralleled by a dose-dependent reduction in liver fibrosis area (Picro-Sirius-Red) of −41% (10 mg/kg) and −69% (30 mg/kg), respectively. The 30 mg/kg cilofexor dose significantly reduced hepatic hydroxyproline content (−41%), expression of col1a1 (−37%) and pdgfr-β (−36%), as well as desmin area (−42%) in NASH rats. Importantly, cilofexor decreased portal pressure (11.9 ± 2.1 vs. 8.9 ± 2.2 mmHg; p = 0.020) without affecting splanchnic blood-flow or systemic hemodynamics. The addition of propranolol to cilofexor additionally reduced splanchnic inflow (−28%) but also mean arterial pressure (−25%) and heart rate (−37%). Conclusion: The non-steroidal FXR agonist cilofexor decreased portal hypertension and reduced liver fibrosis in NASH rats. While cilofexor seems to primarily decrease sinusoidal resistance in cirrhotic portal hypertension, the combination with propranolol additionally reduced mesenteric hyperperfusion

Configurable LDPC Decoder Architecture for Regular and Irregular Codes

Low Density Parity Check (LDPC) codes are one of the best error correcting codes that enable the future generations of wireless devices to achieve higher data rates with excellent quality of service. This paper presents two novel flexible decoder architectures. The first one supports (3, 6) regular codes of rate 1/2 that can be used for different block lengths. The second decoder is more general and supports both regular and irregular LDPC codes with twelve combinations of code lengths −648, 1296, 1944-bits and code rates-1/2, 2/3, 3/4, 5/6- based on the IEEE 802.11n standard. All codes correspond to a block-structured parity check matrix, in which the sub-blocks are either a shifted identity matrix or a zero matrix. Prototype architectures for both LDPC decoders have been implemented and tested on a Xilinx field programmable gate array.NokiaNational Science Foundatio