INVESTIGATION OF FELDSPAR AND ITS EFFECT IN POTTERY BODIES*

The history and purpose of the investigation are outlined and reports are made on (1) fineness determinations, chemical analyses, softening range, softening points, “true” specific gravity, thermal expansion, and petrographic analyses of the individual feldspars; (2) the results of porosity, volume shrinkage during firing, color and translucency, mechanical strength, petrographic analyses, effect of feldspar used on relative “glaze fit,” thermal expansion, and elasticity determinations on vitreous and semivitreous bodies in which feldspar is the only variable component.     

Effect of surface-active substances on the fibre-forming process and properties of nitron fibre

Conclusions The effect of surface-active agents on the surface tension of polyacrylonitrile (PAN) spinning solutions has been studied.It has been found that introducing SAS into the precipitation bath increases fibre-formation stability. The use of SAS as modifying additives to the spinning solution and into the precipitation bath leads to an increase in the uniformity of spun fibre properties.The possibility of reducing the linear density of Nitron fibres on introducing SAS into the spinning solution and the precipitation bath has been demonstrated.Translated from Khimicheskie Volokna, No. 3, pp. 24–26, May–June, 1985.     

Controlled Vocabularies in OODBs: Modeling Issues and Implementation

A major problem that arises in many large application domains is the discrepancy among terminologies of different information systems. The terms used by the information systems of one organization may not agree with the terms used by another organization even when they are in the same domain. Such a situation clearly impedes communication and the sharing of information, and decreases the efficiency of doing business. Problems of this nature can be overcome using a controlled vocabulary (CV), a system of concepts that consolidates and unifies the terminologies of a domain. However, CVs are large and complex and difficult to comprehend. This paper presents a methodology for representing a semantic network-based CV as an object-oriented database (OODB). We call such a representation an Object-Oriented Vocabulary Repository (OOVR). The methodology is based on a structural analysis and partitioning of the source CV. The representation of a CV as an OOVR offers both the level of support typical of database management systems and an abstract view which promotes comprehension of the CV's structure and content. After discussing the theoretical aspects of the methodology, we apply it to the MED and InterMED, two existing CVs from the medical field. A program, called the OOVR Generator, for automatically carrying out our methodology is described. Both the MED-OOVR and the InterMED-OOVR have been created using the OOVR Generator, and each exists on top of ONTOS, a commercial OODBMS. The OOVR derived from the InterMED is presently available on the Web.     

Hot electrons and electron-phonon coupling in a cylindrical nanoshell

We use a standard model for the low-temperature electron-phonon interaction in metals to calculate the rate of thermal energy transfer between electrons and acoustic phonons in suspended metallic nanoshells. The electrons are treated as three-dimensional and noninteracting, whereas the vibrational modes are that of an thin cylindrical elastic shell of radius R with a free surface and thickness h. Disorder is neglected. The temperature dependence of the thermal power is obtained analytically for this model, and a crossover from the T3 dependence expected for one-dimensional phonons to a T3/(1 - v2) + 9gammaT4/[T*(1 - v2)(3/2)] dependence is obtained.     

Particle Deposition in Parallel-Plate Reactors: Simultaneous Diffusion and External Forces

Particle deposition resulting from uniform external forces and Brownian motion is modeled in a parallel-plate reactor geometry characteristic of a wide range of semiconductor process tools: uniform, isothermal, downward flow exiting a perforated-plate showerhead separated by a small gap from a parallel, circular wafer. Particle transport is modeled using a Eulerian approach neglecting particle inertia and interception. Particles are assumed to originate in a planar trap located between the plates, such as would result for particles released from a plasma-induced particle trap after plasma extinction. Flow between infinite parallel plates is described by an analytic quasi-one-dimensional creeping flow approximation, where the showerhead is treated as a porous plate. An analytic, integral expression for particle collection efficiency (fraction of particles that end up on the wafer) is derived as a function of four dimensionless parameters: the flow Reynolds number, a dimensionless trap height, a dimensionless particle drift velocity, and the particle Peclet number. Numerical quadrature is used to calculate particle collection efficiency in terms of the controlling dimensionless parameters for external forces, which either enhance or inhibit particle deposition. Example calculations of collection efficiency are also presented in dimensional terms for a representative set of process conditions. Strategies to reduce particle deposition include the use of a protective external force and manipulation of the trap to keep it as far from the wafer as possible.     

Acquisition of the Ph chromosome and BCR-ABL fusion product in AML-M2 and t(8;21) leukemia: cytogenetic and FISH evidence for a late event

A patient with the M2 subtype of AML who had a 45,X,-X,t(8;21) karyotype at diagnosis was found to have the Ph chromosome in one out of 37 evaluated cells 18 months after the initial diagnosis. Interphase FISH studies utilizing a BCR-ABL dual-color probe did not detect a fusion product 4 months prior to the appearance of one Ph-positive cell. Nineteen months post diagnosis and 5 months after clinical relapse all evaluated cells had the Ph chromosome in a clone characterized by t(8;21). These observations suggest that late appearing Ph is a secondary event which may be either therapy-related or consistent with one of the later events in a multistep pathogenesis of AML.     

Some special features in forming current-conducting structures in gel-fibres

Conclusions Structural-mechanical properties of metallized fibres have been studied. The correctness of hypotheses advanced about the mechanism of formation of current-conducting structures has been confirmed.The following mechanisms have been proposed for the interaction of the polymer with Ni²⁺, Ni, and NiS during the metallization process and for the formation of current-conducting structures in Nitron gel-fibre; formation of intra- and intermolecular salt bonds between carboxyl groups of the polymer and Ni²⁺; realization of donor—acceptor interaction of Ni²⁺ and NiS with functional groups of the polymer to form compounds of the chelate type.Translated from Khimicheskie Volokna, No. 1, pp. 20–22, January–February, 1990.     

Transfer ionization with bare 100 keV Ne10+ ions colliding with noble gas atoms

A crossed-beam coincidence time-of-flight technique has been used to measure the charge-state distribution of rare-gas recoil ions created by fully stripped Ne¹⁰⁺ projectiles which capture one electron in single collisions at 100 keV impact energy. The results of the investigation show the importance of transfer ionization as a contribution to charge-transfer processes: with increasing target atomic number the fraction of singly charged recoil ions decreases in favor of emission of additional target electrons. For xenon, recoil ion charge states up to Xe⁵⁺ have been observed.