Showing papers by "Leibniz University of Hanover published in 1983"
TL;DR: In this article, the surface and subsurface reactions involving intrinsic surface defects are separated from each other by analyzing the charge transfer model, which takes into account surface and bulk electronic states in the band gap attributed to the different defects formed during the interaction.
Abstract: The interaction of Ti${\mathrm{O}}_{2}$(110) with ${\mathrm{O}}_{2}$, ${\mathrm{H}}_{2}$, CO, and C${\mathrm{O}}_{2}$ was studied by means of low-energy electron diffraction, x-ray photoelectron spectroscopy, electron energy-loss spectroscopy, thermal desorption, electron paramagnetic resonance, and measurements of changes in surface conductivities, $\ensuremath{\Delta}\ensuremath{\sigma}$, and work functions, $\ensuremath{\Delta}\ensuremath{\phi}$, for $300\ensuremath{\le}T\ensuremath{\le}1000$ K with particular emphasis on surface reactions involving intrinsic surface defects $2{\mathrm{Ti}}^{3+}\ifmmode\cdot\else\textperiodcentered\fi{}V_{O}^{}{}_{}{}^{(+)}$. The defects are thermodynamically stable at high temperatures and act as donors and specific adsorption sites for ${\mathrm{H}}_{2}$ and CO. Surface and subsurface reactions involving ${\mathrm{O}}_{2}$, ${\mathrm{H}}_{2}$, CO, and C${\mathrm{O}}_{2}$ can be separated from each other by analyzing the $\ensuremath{\Delta}\ensuremath{\sigma}$ and $\ensuremath{\Delta}\ensuremath{\phi}$ effects in a charge-transfer model, which takes into account surface and bulk electronic states in the band gap attributed to the different defects formed during the interaction.
476 citations
TL;DR: In this article, the authors investigated the effect of Δ on the three-nucleon charge and magnetic form factors and on the weak decay of the three nucleon bound states.
104 citations
TL;DR: In 21 varieties of stone and pome fruit the quinic acid esters of caffeic, p-coumaric and ferulic acids have been determined by capillary GC and HPLC as mentioned in this paper.
66 citations
TL;DR: In this paper, the authors proposed modifications of the standard sludge volume index (SVI) to eliminate its unpredictable variation with suspended solids (SS) concentration, including stirring, conduct of the test at constant SS concentration, and dilution.
66 citations
TL;DR: In this paper, the 2-norzizaenes were obtained from allylic alcohol in one step in 16% yield using diazene in a single step in order to obtain 2.7,7-dimethyl-6-methylidenetricyclo[6.2.1.1]undec-9-ene.
Abstract: 7,7-Dimethyl-6-methylidenetricyclo[6.2.1.01,5]undec-9-ene (10) has been prepared from allylic alcohol 8 in one step in 16% yield. Selective hydrogenation of 10 with diazene gives the 2-norzizaenes 1a and 11.
37 citations
TL;DR: The transfer rate of radioactive iodide to roots decreased remarkably with increasing amount of stable iodide in the culture solution, whereas that to shoots remained relatively constant indicating that the element content in shoots increased almost proportionally with the increasing concentration of stable iodine in the solution.
Abstract: Uptake of iodide and iodate by komatsuna, Brassica Rapa var. pervidis, was studied using culture solution containing radioiodine as a tracer. After 24 hours'' exposure, accumulation of iodide in the plant was several times higher than that of iodate. The concentrations of both iodide and iodate in roots were much higher than those in shoots. It was estimated that high accumulation of iodide in roots was due to the adsorption of the element on the root surface. The plant of the earlier growth stage absorbed iodide selectively from the solution. On the contrary that of the older growth stage, more than 40 days after seeding, showed less absorption of the element. Influence of stable iodine content on the uptake of radioiodine was also examined. The transfer rate of radioactive iodide to roots decreased remarkably with increasing amount of stable iodide in the culture solution, whereas that to shoots remained relatively constant indicating that the element content in shoots increased almost proportionally with the increasing concentration of stable iodine in the solution. A significant amount of iodate in the culture solution was transformed to iodide in the presence of plant. The dominant chemical form of iodine in the plant was thought to be iodide.
31 citations
TL;DR: In this paper, a sufficient condition for the difference of mean square error matrices of minimum conditional MSE estimator and minimum average risk linear estimator to be postive definite is derived.
Abstract: This note extends some results on homogeneous linear estimators to the general, even nonlinear case.A Sufficient condition for the difference of mean square error matrices of minimum conditional mean square error estimator and minimum average risk linear estimator to be postive definite is derived.
30 citations
TL;DR: In this article, the 3 He magnetic moment and form factor are calculated with momentum space wave functions of the three nucleon ground state based on the Paris and Reid soft core potentials.
29 citations
TL;DR: In this paper, the validity of dispersion models in both of the phases and of Monod kinetics with regard to oxygen and substrate were assumed, and the longitudinal variations of pressure and model parameters were considered to obtain a good coordination between simulated and measured data.
27 citations
TL;DR: In this paper, the variation of desorption yield with laser frequency was measured at constant fluence and coverage and was correlated with the corresponding linear absorption spectra, showing increasing φ s with decreasing coverage at constant excitation frequency.
27 citations
TL;DR: Inbred rats with experimental autoimmune myasthenia gravis show no correlation between the serum autoantibody concentration and the reduction of endplate acetylcholine‐controlled ionic channels, as measured by a novel electrophysiological technique termed quantitative ionophoresis.
Abstract: Inbred rats with experimental autoimmune myasthenia gravis (EAMG) show no correlation between the serum autoantibody (Antiacetylcholine receptor antibody) concentration and the reduction of endplate acetylcholine-controlled ionic channels, as measured by a novel electrophysiological technique termed quantitative ionophoresis. This has implications for attempts to explain the well-documented lack of correlation between the autoantibody titer and the clinical severity of myasthenia gravis (MG).
TL;DR: In this paper, a perturbative approach to Δ-isobar components of the three-nucleon ground-state wave function is developed, which is based on the transition potential connecting nucleon nucleon partial waves and partial waves with isobars.
TL;DR: The only commercially running closed-cycle gas turbine in the world delivering electricity as well as heat to a public utility and a heating network, is the heat and power station in Coburg, West Germany as mentioned in this paper.
Abstract: The only commercially running closed-cycle gas turbine in the world delivering electricity as well as heat to a public utility and a heating network, is the heat and power station in Coburg, West Germany. The plant is fired exclusively with pulverized coal and uses air as the working medium. It has a maximum continuous electric power output of 6.6 MW into the grid and up to 16 MW of direct heating capacity into the town's heating network. The plant has accumulated 150,000 operating hours to date (approximately 7000 hrs per year); it is scheduled to remain in service during the following years due to its excellent performance. Since relatively little has been published about the plant in the technical literature, a report about its design and operating experience is presented here.
27 Mar 1983
TL;DR: In this paper, the influence of the diffuser inlet shape on the performance of diffuser and the whole compressor stage was investigated using a single-stage centrifugal compressor and three different vaned diffusers.
Abstract: Results from an experimental study of the influence of the diffuser inlet shape on the performance of the diffuser and the whole compressor stage are presented The investigations were carried out using a single stage centrifugal compressor Three different vaned diffusers were tested From detailed flow field measurements the influence of the diffuser inlet shape on the performance of the essential components of the compressor stage, ie the impeller, the diffuser, and the collecting chamber was analyzed It is shown that the reaction of the vaned diffuser on the efficiency of the impeller is only weak but the losses in the collecting chamber are considerably affected by the used diffuser typesCopyright © 1983 by ASME
TL;DR: In this paper, the authors report experimental evidence for the conclusion that this discrepancy is entirely due to different ways of sample preparation, and therefore recommend the use of samples formed directly from the melt.
TL;DR: On etudie l'existence d'algorithmes de colorations pour des graphes localement finis denombrablement infinis.
TL;DR: A quasielastic neutron scattering experiment has been performed on a large single crystal of α-Ag 2 Se as discussed by the authors, where the range of wavevector transfer was 1.0 A −1 ⪅ | Q o| ⪆ 1.8 A − 1 for elastic scattering, which is consistent with a continuous model in which the silver ions are assumed to diffuse within a system of channels.
TL;DR: In this paper, the adsorption of CH 3 F on NaCl between 77 K and 250 K was investigated using infrared spectroscopy under ultra high vacuum conditions, and three phases were detected, the most intense mode, the C-F stretch ν 3, − 102 cm −1 (10 %), while the other modes were much less influenced.
TL;DR: In this article, the authors measured the linear infrared absorption spectrum of the coadsorbate, selective desorption of CH 3 F from the binary CO 2 -CH 3 F-NaCl under ultrahigh vacuum conditions at 12o K stimulated by resonant CO 2 laser pulses of small fluence ∼ 0.1 J·cm −2 has been carried out.
01 Jan 1983
TL;DR: In this paper, three-dimensional linear elastic orthotropic finite elements were used for the approximation of reinforced tyre materials, and different methods to find realistic elastic constants were compared to experimentally obtained results of tension tests.
Abstract: Three-dimensional linear elastic orthotropic finite elements were used for the approximation of reinforced tyre materials. Various authors have expressed analytically the elastic constants. In order to decide which of the different methods to find realistic constants can be recommended, three-dimensional FEM computations have been compared to experimentally obtained results of tension tests. It was found that all the different methods lead to equivalent results.
TL;DR: The role of the medium polarization caused by the pion and rho-meson interactions in nuclear media for corresponding meson exchange contributions to nuclear charge form factors is investigated in this article.
TL;DR: In this article, an investigation has been conducted into the economics of chucking lathes and automatic bar machines versus the newly developed turret-type CNC lathes, which is especially suitable for machine shop programming and is used not only for chucking but also for bar processing.
27 Jun 1983
TL;DR: A new layout verification system, called ALAS (A Layout Analysis System) is presented, which aims to tackle the particular verification problems of analog bipolar circuits.
Abstract: A new layout verification system, called ALAS (A Layout Analysis System) is presented. Its main intention is to tackle the particular verification problems of analog bipolar circuits. At present, the system comprises four main parts: a device recognition program produces a list of devices, a plot program converts these data to a layout-oriented circuit diagram, a connectivity analysis program yields device-oriented or net-oriented descriptions of the derived circuit and a network comparison program tests the consistency of this actual circuit with the intended nominal one. A fifth program, that will calculate the parameters of the actual circuit, is under development. To derive the actual circuit from layout ALAS uses geometrical mask data only; no additional circuit information is needed. If not available from the design system, a description of the nominal circuit may be supplied manually in a SPICE-like input format.
01 Feb 1983
TL;DR: A conceptual framework for design models is presented and an application of the framework is demonstrated by the development of a method for a simultaneous design of an organization's spatial structure, formal structure, and communication equipment.
Abstract: Futuristic scenarios demonstrate far‐reaching impacts of new communication technologies on the spatial as well as the formal structure of organizations. Working‐at‐home can be combined with several modes of task delegation and coordination. Since traditional theories prove ineffective in coping with the new possibilities of design, a conceptual framework for design models is presented. The framework succeeds in showing the scope of the problem as well as essential elements and relations. An application of the framework is demonstrated by the development of a method for a simultaneous design of an organization's spatial structure, formal structure, and communication equipment. The method's central step consists of an adjustment of potential and requirements for communication processes of organizations.
TL;DR: In this article, the complete manuscript of this communication appears in: Angew. Chem. Suppl. 1983, 985; DOI:10.1002/anie.198309850
Abstract: The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1983, 985. DOI:10.1002/anie.198309850
TL;DR: In this paper, the phase equilibrium in the Mn2O3-Mn3O4-mnO system in CO2-H2 Mixtures was investigated. But the experimental results showed that the deviation from stoichiometry, Δ, in Mn1-ΔO are about 40 times higher than those reported by Terayama et al.
Abstract: Recently a paper entitled \"Phase Equilibria in the Mn2O3-Mn3O4-MnO System in CO2-H2 Mixtures\" by Terayama et al.(1) has been published in Trans. JIM. In one part of this publication, experimental resuits on the nonstoichiometry of two manganese oxides, manganosite (Mn1-ΔO) and hausmannite (Mn3-δO4), as function of temperature and oxygen partial pressure have been reported. By comparing these results with data from the literature(2) and from new measurements made by us(3)(4), it is found that considerabie discrepancies occur between the data by Terayama et al.(1) on one hand and the data-sets(3)(4) on the other hand. Our experiments have been performed on dense polycrystalline manganese oxide samples. They were carried out thermogravimetrically using a completely symmetric set-up. Under the conditions of our experiments uncertainty associated with the resolution and the noise level of the microbalance was of the magnitude of 1μg. The oxygen activity was electrochemically monitored in situ. The EMF-cells were located directly near the studied sample. Details are reported in(5). Concerning the nonstoichiometry of manganosite, Terayama et al.(1) have reported values for x, using the notation MnOx, at temperatures of 880°C and 930°C, These can be compared with the corresponding results for 900°C, which are displayed in Fig. 1. It is found that the values reported by Terayama et al.(1) for the deviation from stoichiometry, Δ, in Mn1-ΔO are about 40 times higher than ours for comparable conditions
TL;DR: Investigations for the race analysis of P. hordei (location Cologne, W.-Germany) showed, that most of the resistant genotypes in the International differential set with Pa1 to Pa8 were ineffective for that purpose.
Abstract: Investigations for the race analysis of P. hordei (location Cologne, W.-Germany) showed, that most of the resistant genotypes in the International differential set with Pa1 to Pa8 were ineffective for that purpose.
Out of 80 selected barley genotypes with different degree of resistance against the field-collection RG 1975 hosts with a strongly differentiating effect were chosen. This was done using three parameters: mean resistance xw, its standard deviation xw and the range z. They were calculated from evaluating the reaction types of 80 barley genotypes infected with 116 single-pustule lines of barley brown rust. Eight hosts with strongly differentiating reactions towards the 116 rust lines were composed into a differential set, which could characterize the heterogeneity of the Cologne P. hordei-population essentially better and more precisely than the International differential set.