Addition of a cyclopropyl alkyne to tetramesityldigermene: evidence for a biradical intermediate

The reaction pathway for the addition of alkynes to tetramesityldigermene was examined using a cyclopropyl alkyne mechanistic probe. The results obtained indicate that the reaction is stepwise and involves biradical intermediates.     

Direct observation of the quantum critical point in heavy fermion CeRhSi3

We report on muon spin rotation studies of the noncentrosymmetric heavy fermion antiferromagnet CeRhSi3. A drastic and monotonic suppression of the internal fields, at the lowest measured temperature, was observed upon an increase of external pressure. Our data suggest that the ordered moments are gradually quenched with increasing pressure, in a manner different from the pressure dependence of the Néel temperature. At 23.6 kbar, the ordered magnetic moments are fully suppressed via a second-order phase transition, and T(N) is zero. Thus, we directly observed the quantum critical point at 23.6 kbar hidden inside the superconducting phase of CeRhSi3.     

Measuring the Efficiency of Prescribing by General Practitioners

Data envelopment analysis (a mathematical programming technique) has often been applied to measuring the efficiency with which outputs are produced. The technique derives efficient combinations of outputs for given inputs: constant returns to size may be assumed or one may choose to examine whether decreasing or increasing returns hold true. An analysis of the cost of prescribing drugs for 106 general practices in the Lincolnshire Health Authority for the year 1993/1994 reveals the statistical problems that are encountered in applying this technique.     

Physical mechanisms for the propagation of surface fires

The various physical processes which affect the rate-of-spread of fires on surface fuel beds are discussed. Specifically, these include conduction, radiation from the flame and burning fuel bed, and convective heating influenced by wind. A new interpretation of a laboratory experiment is given, and from this a balance between radiative heating from the flame and convective cooling of the fuel bed is established. The ratio between these two effects may be expressed as a new dimensionless number, P (defined by equation 5.12 or 5.16). If P < 1, radiation from the flame of the fire alone is not capable of causing the fire to spread, whereas if P #> 1, generally it is. Many laboratory experiments have P < 1, whereas P #> 1 for moderate to large fires in the field. The most significant factor affecting fire propagation is wind, which increases both radiative and convective heating. Much of this process is turbulent and involves large eddies in the boundary layer and fuel canopy, and their interaction with fires is currently poorly understood.     

Crystalline effects in backscattering and Auger production

Measurements have been made of the variation of the backscattered intensity and of the Auger signal intensity as a function of the direction of the incident electron beam using a (111) Al surface and an incidence energy of 1.5 keV. The dynamical theory of electron diffraction and backscattering is able to account for the results quantitatively to within a factor of about two in the case of the quasi elastic and first plasma loss backscattered components. The variation measured for the Auger signal is significantly greater than for backscattered electrons of similar energy.     

Third International Workshop of the Soochow University–Western University Centre for Synchrotron Radiation Research

Following the two previous international workshops successfully held in 2012 [1 Y. Song, Synchrotron Radiation News 26(2), 39 (2013).[Taylor &; Francis Online] , [Google Scholar]] and 2014 [2 Y. Song, Synchrotron Radiation News 27(5), 25–26 (2014).[Taylor &; Francis Online] , [Google Scholar]], both in Suzhou, China, the Third International Workshop on Synchrotron Radiation Research took place on July 16, 2015, on the campus of the University of Western Ontario (also known as Western University), London, Ontario, Canada, for the first time. The workshop was sponsored by the Soochow University–Western University Centre (SWC or the Centre) for Synchrotron Radiation Research and hosted by Western University, with financial support from Western's Interdisciplinary Development Initiative (IDI) program.     

μSR study of internal magnetic fields in superconducting La1.9Sr0.1CuO4 in the mK region

Muon-spin-rotation (μSR) experiments were performed on superconducting La_1.90Sr_0.10CuO₄ in zero external field. Below 2 K, a fast depolarization of the muon signal is observed, indicating that internal magnetic fields are present at the muon site. The average magnitude of the magnetic field in La_1.90Sr_0.10CuO₄ is in the order of 3 mT and thus approximately 14 times smaller than the corresponding field in antiferromagnetic La₂CuO₄. The present data support theoretical models of superconductivity in which magnetic correlations are responsible for pairing.