Analyse des Wassers

Ohne Zusammenfassung     

New lasers and laser schemes

Conclusion We have demonstrated the existence of an anomalous polarization coupling mechanism present in the injection locked TEA CO₂ laser. As a direct consequence of this work, a new injection technique has been formulated which permits efficient injection coupling and maximises energy extraction whilst eliminating the detrimental optical feedback effects to which other injection locking systems are prone.Supported by the Office of Naval Research and the National Science Foundation     

Mechanism of thermolysis of tetramethylammonium μ-chlorobis(triethylaluminate)

The thermolysis of tetramethylammonium μ-chlorobis(triethylaluminate) has been investigated. In addition to the previously reported products, [Me₄N][ClAlEt₃] and (AlEt₃)₂, Me₃N · AlEt₃ is formed simultaneously in lesser amounts. A mechanism for the observed thermolysis reactions is presented which predicts formation of methyl chloride as a transient species which undergoes further reaction with (AlEt₃)₂ to ultimately produce methane and ethylene. The experimentally observed methane/ethylene ratio supports the proposed mechanism.     

Speciation of butyltin compounds in oyster samples

Experimental instrumentation for the speciation of butyltin compounds by hydride generation and gas chromatography-quartz furnace atomic absorption spectrometry is described. Evaluation of a number of extraction methods revealed that simple acid leaching of oyster samples gave adequate recoveries. The levels of each butyltin species in oyster flesh and gill are reported together with the tentative identification of a mixed methylbutyltin compound.     

The analysis of some discontinuous decision processes

We identify some problems that give rise to expected loss functions that are smooth but nonetheless evolve to exhibit marked discontinuities in the trajectory of their associated Bayes decisions. The cusp catastrophe is used to describe and explain many of these phenomena.     

The reactions π±p→pX± (900–1020 MeV) near threshold

We observe no structure in the X^± spectra as our mass resolution of 12 MeV FWHM. Thus the X⁰(957) of Binnie et al., is determined to be the I = 0 η′. A braid structure at a mass of 976 MeV can be accommodated.     

Transmission circuits for thick-transducer ultrasound transmission test systems

Pulse techniques for the measurement of ultrasonic absorption over a wide frequency bandwidth are limited by the narrow band nature of conventional piezoelectric transducers. This problem can be overcome if the piezoelectric devices are operated as thick elements. In this paper the insertion characteristics of transducers operating in this mode are determined. The compromise between system sensitivity, bandwidth and noise generation in receiving circuits is examined.It is shown that high voltage generators with rise times of a few nanoseconds are required to drive thick transmission transducers. The design of suitable generators, based on avalanche operation of one or more bipolar transistors is described in detail. It is concluded that exciting signals of sufficient amplitude and short enough rise-time could be generated for absorption measurements to be made over at least two decades of frequency with a dynamic range of 100 dB without a change of transducer.