Metal oxide-semiconductor capacitors on silicon carbide

The purpose of the work discussed in this paper is to determine the feasibility of using Silicon Carbide for making surface field effect devices such as MOSFET's. The device used for making such a determination is the MOS capacitor.This paper discusses briefly the oxidation of Silicon Carbide. The techniques used to make MOS capacitors are outlined, and experimental data are presented which show that it is possible to use Silicon Carbide for constructing surface field effect devices.     

RANDOM COEFFICIENT AUTOREGRESSIVE PROCESSES:A MARKOV CHAIN ANALYSIS OF STATIONARITY AND FINITENESS OF MOMENTS

Abstract. Simple yet practically efficient conditions for the ergodicity of a Markov chain on a general state space have recently been developed. We illustrate their application to non-linear time series models and, in particular, to random coefficient autoregressive models.
As well as ensuring the existence of a unique stationary distribution, geometric rates of convergence to stationarity are ensured. Moreover, sufficient conditions for the existence and convergence of moments can be determined by a closely related method. The latter conditions, in particular, are new.     

Enzymatischer Nachweis von Carbamat-Pesticiden auf impr?gnierten Cellulose-Platten

Zusammenfassung Ein Nachweis für Carbamat-Pesticide mittels Enzym-Inhibition auf imprägnierten Cellulose-Schichten wurde ausgearbeitet. Bei Celluloseschichten, die mit Äthylglykol, Triäthylglykol und,-Ogydipropionitril imprägniert waren, erwies sich die Kombination Schweineleberesterase/Indophenylacetat (als chromogenes Substrat) als besonders empfindlicher Nachweis. Die Nachweisempfindlichkeit wurde in Abhängigkeit von der Art des Enzympräparates, des Substrates, des pH, der Inhibitionszeit und -temperatur, der Schichtdicke und des Impriignierungsmittels untersucht.

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Enzymatic detection of carbamate pesticides on impregnated cellulose plates

Summary The detection of carbamate pesticides by an enzyme-inhibition method on impregnated (ethylene glycol, triethylene glycol,,-ogydipropionitrile) cellulose thin layer plates is described. The enzyme-substrate combination: pig liver esterase-indophenylacetate (chromogenic substrate) was the most sensitive. The following parameters concerning the sensitivity of the method were investigated: enzyme source, substrate, pH, inhibition time, inhibition temperature, thickness of the cellulose layer, stationary phase.

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Herrn o.Univ.-Prof. Dr. O. Hoffmann-Ostenhof, Vorstand des Instituts für Allgemeine Biochemie, Universität Wien, zum 60. Geburtstag gewidmet.

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Wir danken dem Fonds zur Förderung der wissenschaftlichen Forschung, der uns die Durchführung dieser Arbeit (Projekt Nr. 2161) ermöglichte.

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Ing. B. Rapié dankt der SEA-Stiftung (Scientific Exchange Agreement) für die Gewährung eines Stipendiums.     

Internal oxidation of lead-tin alloys

From the measurement of the widths of internal oxidation zones in dilute Pb-Sn alloys, the product of the solubility N _o ^(s) and diffusivity D_o of oxygen in lead was obtained from 225 to 320° C. The enhancement factor for Sn was calculated from the experimental values of N _o ^(s) D_o and compared to the results obtained by x-ray fluorescence measurements. The results indicated that the aging of Pb-Sn alloys observed at high temperatures is due to internal oxidation which causes the migration of tin toward the specimen surface.     

Photoeffects in ZnSiP2

Photoconductive and photovoltaic effects have been studied in n-type ZnSiP₂ platelets prepared from the vapor phase. The spectral responses extend from 1.5 eV to beyond 3.1 eV with peak signals in the 2.2-2.7 eV interval. Intrinsic (band-to-band) photoexcitation occurs at all energies, arising from the shallow energy dependence of the optical absorption edge. Trapping effects limit the photoconductive response time to 4xl0^-3sec. Peak spectral responsivity and detectivity values of 840 V/W and 9.5xl0⁹cm Hz 1/2 W⁻¹respectively are found for one sample.     

A central cholinergic inhibitory system as a basis for tonic immobility (animal hypnosis) in chickens.

4 experiments provided support for the hypothesis that tonic immobility (TI) in chickens, which may be analogous to response suppression in the rat, is a result of fear and is mediated by central cholinergic systems. A total of 124 experimental and 54 control, White Leghorn cockerel chicks were the Ss. Exp I established that scopolamine, a central and peripheral acting anticholinergic, will reduce the duration of TI, whereas methylscopolamine, which acts only peripherally, will not. Exp II established a dose-response curve for scopolamine and TI. Exp III demonstrated that scopolamine increased activity and that this increase may be a factor in reducing the duration of TI. Exp IV showed that physostigmine, which blocks acetylcholinesterase and allows longer action of acetylcholine at the synapse, increased the duration of TI. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The specificity of response interference to schizophrenia.

Recent research has emphasized that the greater-than-normal response interference in schizophrenics is a specific characteristic of schizophrenia. Since arousal is an important variable in response interference and since schizophrenics show patterns of overarousal, it is suggested that arousal would be important to control if behavioral differences between schizophrenics and controls are to be attributed specifically to schizophrenics' special problems of response interference. These ideas were tested by replicating a study by W. E. Broen and L. H. Storms (see record 1964-07261-001) using an overaroused control group of 15 nonpsychotic psychiatric inpatients, 15 nonparanoid schizophrenics, and 15 normals in a visual discrimination task. Data show that both the overaroused controls and schizophrenics, while not differing from each other, showed greater decrement of correct responding with increased arousal than the normal controls. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

N-nitrosodimethylamine formation by free-chlorine-enhanced nitrosation of dimethylamine

The formation of N-nitrosodimethylamine (NDMA) by the nitrosation of dimethylamine (DMA) is greatly enhanced by the presence of free chlorine (HOCl). The effect of HOCl appears at first to be contrary because HOCl rapidly oxidizes nitrite and hence should reduce NDMA formation from a mechanism involving classical nitrosation. The enhanced nitrosation by the presence of HOCl is, however, consistent with a mechanism that involves the formation of a highly reactive nitrosating intermediate such as dinitrogen tetroxide (N2O4) formed during the oxidation of nitrite to nitrate. This mechanism is quite unlike another recently proposed NDMA formation pathway involving the rate-limiting oxidation of DMA directly by monochloramine. NDMA formation by the proposed HOCl-enhanced nitrosation pathway is inhibited by the presence of ammonia and occurs very quickly, only during the short period during which nitrite oxidation occurs. The general importance of this NDMA formation mechanism in actual drinking water appears to be limited by the amount of DMA and nitrite typically present. The mechanism described here, however, suggests the potential involvement of other nitrogen redox reactions that may produce reactive intermediates leading to the indirect and incidental formation of NDMA in the presence of appropriate organic nitrogen precursor.     

Field electron and ion emission from charged surfaces: a strategic historical review of theoretical concepts

The field-electron (FE) and field-ion techniques directly observe and measure atomic-level surface processes that occur in very high electric fields. In theoretical terms, the high fields put large additional terms into Hamiltonians and free energies, and significantly modify many aspects of the surface physics and chemistry, as compared with the field-free situation.This paper presents a strategic review of the fundamental science of some of these high-field surface effects and processes, as developed in the context of the field electron and ion emission techniques. It outlines the main theoretical concepts developed, notes some twists of scientific history, and suggests useful contributions made to mainstream science. Topics covered are basic aspects of FE emission, surface field ionisation, localised field adsorption, charged surfaces theory, field-ion image contrast theory and associated imaging-gas kinetics, field evaporation, and aspects of the thermodynamics of charged surfaces. Despite many years of effort, important aspects of the theory remain incomplete. Some theoretical challenges are noted.