Positive Linear Forms Vanish on the Radical

If A is a complex *-algebra with unit then every linear form L on A which is positive in the sense that for all vanishes on the Jacobson radical of A.     

Levels in 106Ru and 108Ru

The decay schemes of 36 s ¹⁰⁶Tc and 5 s ¹⁰⁸Tc have been studied with γ-ray singles and γ-γ coincidence measurements. To separate the technetium nuclides from the fission products of ²³⁹Pu, an on-line chemical separation procedure has been developed which is based on multistep chemical separations of liquid phases by fast-rotating centrifuges (“SISAK”). The resulting level schemes of ¹⁰⁶Ru and ¹⁰⁸Ru, together with those of ¹⁰²Ru and ¹⁰⁴Ru, are interpreted in terms of the generalized collective model of Gneuss and Greiner. The potential-energy surfaces calculated from the spectroscopic data show a trend towards triaxial shapes for the very neutron-rich Ru nuclei.     

Acoustic traffic signal for blind pedestrians

The development of an acoustic traffic signal for blind pedestrians is described. The WALK and WAIT signals used represent a compromise between many contradictory demands, e.g. easy localisation and detection in a background of traffic noise, minimum annoyance, maximum attenuation into dwellings and simple and reliable construction. The WALK sound consists of 200 ms pulses at a repetition rate of 2·5 Hz. The WAIT sound consists of 400 ms pulses at a repetition rate of 0·5 Hz. Both WALK and WAIT pulses are formed from an 880 Hz sawtooth or square wave signal.A weak attention signal is audible (automatic level control) within a distance of 2–3 m from the traffic light pole. The system has been in use for more than 2 years. Twenty-six blind pedestrians tested the system and found it very useful. A questionnaire investigation showed no adverse reactions from neighbours to the system. The attention system is being standardised in Denmark. The system is prepared for extension with a louder guiding signal which guides the blind across the crossing.     

23种挥发性有机化合物在3种吸附剂上漏出容量的测定评价

采用吸附热解吸－气相色谱－质谱法对23种挥发性有机化合物Chromosorb 106、Tenax TA、Tenax TG等3种吸附剂上漏出容量进行了测定。根据实验结果确定了不同的化合物应选择不同的吸附剂及相应的采样体积。结果表明,Chromosorb 106可较好地吸附低沸点的挥发性有机化合物,Tenax TA、Tenax TG均可用于沸点较高的挥发笥有机化合物吸附,这对测定大气中的有机化合物含量采样有一定的参考价值。     

Growth Rates for Semiflows on Hausdorff Spaces

In this paper, we present a theory of vector-valued growth rates for discrete- and continuous-time semiflows on Hausdorff spaces. For a given compact flow-invariant set M and an associated growth rate, we introduce the uniform growth spectrum over M, and associated real-valued spectra via projections of the vector-valued spectrum onto one-dimensional subspaces. We show that these real-valued spectra are closed intervals if M is additionally connected. We also define the Morse spectrum associated with a growth rate by evaluating the growth rate along chains. Moreover, we relate the uniform growth spectrum to the Morse spectrum and we analyze the meaning of limit sets for the long-time behavior of growth rates.