Graphic method of substrate doping determination from C–V characteristics of MIS capacitors

A simple graphical method is presented which determines of the Fermi potential (substrate doping) from the high-frequency C–V characteristic of the MIS capacitor. This method is of general application and can be used for the study of any dielectric-semiconductor system at various ambient temperatures.     

Development of a diagnostic technique based on Cherenkov effect for measurements of fast electrons in fusion devices

A diagnostic technique based on the Cherenkov effect is proposed for detection and characterization of fast (super-thermal and runaway) electrons in fusion devices. The detectors of Cherenkov radiation have been specially designed for measurements in the ISTTOK tokamak. Properties of several materials have been studied to determine the most appropriate one to be used as a radiator of Cherenkov emission in the detector. This technique has enabled the detection of energetic electrons (70 keV and higher) and the determination of their spatial and temporal variations in the ISTTOK discharges. Measurement of hard x-ray emission has also been carried out in experiments for validation of the measuring capabilities of the Cherenkov-type detector and a high correlation was found between the data of both diagnostics. A reasonable agreement was found between experimental data and the results of numerical modeling of the runaway electron generation in ISTTOK.     

Eine Abänderung des von H. König ausgearbeiteten Hochspannungs-Meßverfahrens

Zusammenfassung Gezeigt wurde, daß man das Verfahren von König so abandern kann, daß es leichter zu benutzen ist. Zu diesem Zwecke muß man an Stelle der Zusatzbatterie einen Kondensator einschalten. Für die Praxis wird am besten die am Kondensator auftretende SpannungV mit einem elektrostatischen Voltmeter gemessen. Damit die zeitliche Zunahme der SpannungV langsam genug vor sich geht, muß die KapazitätC ₀ des Kondensators etwa 150 F betragen.     

Diffusion pressure welding of NiAl and Ni3Al-based alloys with St3S steel

Alloys containing phases on intermetallic structures, known as intermetallic compounds, belong to the new generation of metallic materials which possess properties lying between those of metals and ceramics. They are alloys of two or more metals which have crystalline structures that are different from those of the crystalline structures of individual component metals. For a number of years, intermetallic compounds were regarded as useful when they appeared as dispersed phases in conventional alloys, but in many situations, for example in the bonding of ceramics with metals, such phases are undesirable because of their brittleness. However, as the knowledge of their unique properties, especially of their behaviour at elevated temperatures and in hostile environments increases, the idea of using this group of materials for constructional purposes has been born. Systems containing intermetallic compounds had been investigated and it was shown that a new and unique group of alloys can be created by combining the matrices of nickel, iron and titanium with that of aluminium.     

Comparative tests of steel car body sheet welds made using CMT and MIG/MAG methods

Results of tests on the influence of automatic welding process parameters using the cold metal transfer (CMT) method on the quality of lap joints made of 0.8 mm steel car body sheets (DC 04) were described. These joints were compared with joints executed using a traditional short arc in gas shielding (MAG). Research work included visual and metallographic inspections, microhardness measurements, and mechanical properties tests of the welded joints. It was noted that the CMT method allowed for the joining of thin workpieces at much higher velocities than previously used in arc welding in shielding gases (approximately four times faster than using MIG/MAG methods), while maintaining very good quality. Metallographic tests were also used to state the changes taking place in the joint and welded material depending on parameter changes. Additionally, attempts were made to determine a mixing factor for both upper and lower metal sheets. It was observed that increased arc length caused deeper depth of fusion of the material of the lower sheet, resulting in an incremental increase in the mixing factor.     

Effect of wheat malt on the concentration of metal ions in wort and brewhouse by‐products

The ionic composition of brewer's wort depends on the raw materials and processing employed. The macroelement content is usually sufficient for yeast, but some of the microelements (mainly zinc) often need to be supplemented to the wort. Wheat malt is used as an adjunct in the production of beer, replacing up to 60% of barley malt. In this study, the effect of replacing barley malt with wheat malt on the concentration of magnesium, manganese, iron and zinc ions in brewer's wort was investigated. The ionic content of both the raw materials and by‐products were analysed. Similar amounts of magnesium ions were found in wheat malt and barley malt, whereas, manganese, zinc and iron were more abundant in the wheat malt. Nevertheless, wheat malt did not cause a significant change in ion concentration in the first wort (except for magnesium; its content decreased). The ionic content in the spent grains increased owing to wheat malt addition; the concentration of ions in the wort decreased after wort boiling (Mn²⁺ and Fe) or remained unaffected (Mg²⁺ and Zn²⁺). It was concluded that the ionic composition of the wort depends mainly on the removal rate of ions from the wort during mash filtration and hot trub separation, rather than on the actual amount of ions in the raw materials. Copyright © 2015 The Institute of Brewing & Distilling     

Improvement of electro-physical properties of ultra-thin PECVD silicon oxynitride layers by high-temperature annealing

Ultra-thin (5 and 6 nm) silicon oxynitride layers have been fabricated by the plasma-enhanced chemical vapour deposition (PECVD) process. Split experiments with annealing of the deposited dielectric layers were performed using the RTP reactor and a standard furnace, both at 900 °C. Possible changes in properties, structure and chemical composition of the obtained layers were investigated by means of spectroscopic ellipsometry, X-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS) and electrical characterisation of manufactured test structures (metal-insulator-semiconductor (MIS) capacitors and MISFETs). The results achieved have shown that annealing at high temperature causes improvement of the properties of ultra-thin silicon oxynitride layers (e.g. lower interface traps density, lower leakage currents within the dielectric layer and lower charge-pumping currents of the MISFETs). The observed improvement in electro-physical properties can be attributed to the increase of the SiON phase. Moreover, comparison between the physical thickness and the equivalent oxide thickness (EOT) of the layers shows a decrease in physical thickness obtained by using the silicon oxynitride layer instead of the classical silicon dioxide. These findings are important for the consideration of chances of PECVD oxynitride layer application for CMOS technology.     

The effects of high doping on the I-V characteristics of athin-film SOI MOSFET

Modifications of the Ortiz-Conde et al., model which take into account either apparent or physical bandgap narrowing have been presented. The influence of high doping effects is investigated by means of a comparison of the modified models with their original, version for various device parameters. It is shown that the inclusion of bandgap narrowing is essential for accurate simulation of I-V characteristics of a SOI MOSFET in the subthreshold and near-threshold regions. A new analytical model with bandgap narrowing has been derived for the subthreshold region     

Down-regulation of the expression of three major rat liver cytochrome P450S by endotoxin in vivo occurs independently of nitric oxide production

Endotoxemia results in both the down-regulation of multiple cytochrome P450 genes and the induction of inducible nitric oxide synthase (NOS2). The nitric oxide (NO) released during inflammation has been implicated as the mediator of the decreased catalytic activity and expression of several cytochrome P450 isozymes. We examined the role of NO in the decreases of both gene expression and activity of three major P450s in the endotoxemic Fischer 344 rat. Endotoxin (LPS) treatment suppressed both mRNA and protein expression of P450 2C11, 2E1, and 3A2. Coadministration of the NOS inhibitor aminoguanidine to LPS-treated rats completely inhibited the release of NO into the plasma but did not reverse the down-regulation of expression of any of the P450s examined at three time points. LPS treatment had a biphasic effect on some P450 catalytic activities. The hydroxylation of testosterone at the 2alpha-, 16alpha- and to a lesser extent 6beta-positions, was inhibited 6 hr after LPS treatment and returned to normal by 12 hr. The role of NO in the 6 hr effects could not be assessed due to effects of the aminoguanidine treatment itself. The second phase of decreased P450 activities seen after 24 hr was attributed to the NO-independent decrease in gene expression. Our results suggest that NO is not required for the LPS-evoked down-regulation of P450 2C11, 2E1 and 3A2 mRNA or protein expression. We cannot rule out a possible role for NO in the decreases in P450 activities seen early in the response.     

Physiological and pathophysiological regulation of cytochrome P450

This article is a report on a symposium sponsored by the American Society for Pharmacology and Experimental Therapeutics and held at the April 1998 Experimental Biology '98 meeting in San Francisco. The presentations focused on the mechanisms of regulation of cytochrome P450 gene expression by developmental factors and by hormones and cytokines, as well as on the interplay between physiological and chemical regulation. Approaches and systems used to address these questions included conditional gene knockouts in mice, primary hepatocyte cultures, immunofluorescence imaging of cells, and cell lines stably expressing reporter gene constructs.