Die Erhöhung des lichtelektrischen Effektes von Kalium durch Wasserstoff

Zeitschrift für Physik A Hadrons and nuclei - Es werden Versuche beschrieben, die den Schluß zulassen, daß zur Herstellung einer lichtelektrisch hochempfindlichen...     

Cybernetic optimization by simulated annealing: Accelerating convergence by parallel processing and probabilistic feedback control

The convergence of the simulated annealing algorithm is accelerated by a probabilistic feedback control scheme. This scheme uses two or more parallel processors to solve the same or related combinatorial optimization problems and are coupled by a probabilistic measure of quality (PMQ). The PMQ is used to generate an error signal for use in feedback control. Control over the search process is achieved by using the error signal to modulate the temperature parameter. Other aspects of control theory, such as the system gain and its effects on system performance, are described. Theoretical and experimental results show that such a scheme increases the steadystate probability of the globally optimal solutions.     

Relatively pseudocomplemented semilattices amalgamate strongly

Letk be any finite or infinite cardinal andS _ω the symmetric group of denumerable infinite degree. It is shown that fori<k ifG _i is thei-th row of a matrix whose columns are allk-termed sequences of elements ofS _ω in each of which all but a finite number of terms are equal to the identity ofS _ω thenG _i 's (withG _i ⁻¹ 's defined in an obvious way and with coordinatewise multiplication amongG _i 's andG _i ⁻¹'s) generate the Free Group onk free generatorsG _i . Analogously, Free Abelian and other types of free groups are also constructed. Presented by L. Fuchs.     

Über Struktur und Halbleitereigenschaften epitaxialer Bleiselenid-Schichten auf Alkalihalogenid-Einkristallen

Zeitschrift für Physik A Hadrons and nuclei - Epitaxial layers of lead selenide have been grown by way of evaporationin vacua onto substrates of single crystal alkali halides, their thickness...     

Low-level and ultralow-volume hollow waveguide based carbon monoxide sensor

We demonstrate an ultralow sample volume optical carbon monoxide sensor with detection sensitivity of 180 parts in 10(9) (1σ at 1 Hz). The utilization of a 2.3 μm surface-emitting laser directly coupled to a 3 m hollow capillary fiber as the gas cell is proven to be a compact, sensitive, and cost-efficient gas sensing concept. By mechanical vibration of the fiber, an absorbance resolution of 10(-5) is achieved, which is comparable to single-reflective (double-pass) cells. An improvement of sensitivity over the conventional single-reflective cell is thus approximately linearly scaled with the enhancement of the optical path length, which is usually more than 1 order of magnitude.     

Properties of blends of poly(vinyl chloride) and chlorinated polyethylene. I. Optical methods of characterization of PVC multiphase systems

Hitherto it has not been possible to produce a microscopic image with adequate resolution of the high-impact two-phase system poly(vinyl chloride) (PVC)/chlorinated polyethylene (CPE) due to inadequate phase contrast. With the aid of various chemical staining methods and through ion etching, a way has been found for studying the microstructure of the PVC/CPE system by light microscopy and electron microscopy. These independent visualization techniques and scanning electron micrographs of fracture surfaces show, as the morphology with optimal mechanical and rheological properties, networklike distribution of the rubber phase and, imbedded in this, a PVC phase consisting of primary particles.     

Pattern Recognition in Auditory Research

Our group works on the relation between sound‐exposure and auditory performance. During the last decade we thoroughly tested the sense of hearing of about ten thousand persons, and we tried to determine their exposure to sound by a detailed questionnaire. Persons were grouped according to their occupation or their acoustic environment, such as orchestra musicians, office personnel, airline pilots, Tibetian nomads, university students, etc. One of the problems is aging of the ear, the mechanisms of which are not really understood, and its progression varies widely from person to person. Another important aspect is presented by noise‐induced auditory damage, in itself a set of complicated relations that involves continuous noise, as well as rare events of high sound pressure (impulses). Using special procedures to analyse the data, we worked out group curves that are specific for the particular group. Comparing these results among the various groups gives good insight into their sense of hearing, and it also reveals strong training effects by the acoustic environment on the auditory performance, something that is totally new to current concepts. Some patterns can be “seen” and understood quite well, but so far not on a mathematical basis. Other patterns are hard to grasp. However, we assume that the application of pattern recognition can greatly improve the understanding of these fascinating relations. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)