Platinum diffusion into silicon from PtSi

We have observed platinum diffusion into the silicon underlying a PtSi film. Silicon substrates covered with platinum films were annealed at temperatures from 300 to 800°C to form the silicide. Backscattering spectrometry spectra show no degradation of the silicide in the samples treated below 700°C. Deep level transient spectroscopy (DLTS) was used to measure diffused platinum electron traps. Electron trap concentrations in samples treated below 700°C are below the DLTS detection limit of 5×10^11/cm^3. Trap concentration profiles for the samples annealed at higher temperatures were obtained. These profiles cannot in general be explained by simple diffusion from an infinite source of platinum at the surface

Numerical and analytical bounds on threshold error rates for hypergraph-product codes

We study analytically and numerically decoding properties of finite rate hypergraph-product quantum LDPC codes obtained from random (3,4)-regular Gallager codes, with a simple model of independent X and Z errors. Several non-trival lower and upper bounds for the decodable region are constructed analytically by analyzing the properties of the homological difference, equal minus the logarithm of the maximum-likelihood decoding probability for a given syndrome. Numerical results include an upper bound for the decodable region from specific heat calculations in associated Ising models, and a minimum weight decoding threshold of approximately 7%.Comment: 14 pages, 5 figure

Transient response for interaction of two dynamic bodies

During the launch sequence of any space vehicle complicated boundary interactions occur between the vehicle and the launch stand. At the start of the sequence large forces exist between the two; contact is then broken in a short but finite time which depends on the release mechanism. The resulting vehicle response produces loads which are very high and often form the design case. It is known that the treatment of the launch pad as a second dynamic body is significant for an accurate prediction of launch response. A technique was developed for obtaining loads generated by the launch transient with the effect of pad dynamics included. The method solves uncoupled vehicle and pad equations of motion. The use of uncoupled models allows the simulation of vehicle launch in a single computer run. Modal formulation allows a closed-form solution to be written, eliminating any need for a numerical integration algorithm. When the vehicle is on the pad the uncoupled pad and vehicle equations have to be modified to account for the constraints they impose on each other. This necessitates the use of an iterative procedure to converge to a solution, using Lagrange multipliers to apply the required constraints. As the vehicle lifts off the pad the coupling between the vehicle and the pad is eliminated point by point until the vehicle flies free. Results obtained by this method were shown to be in good agreement with observed loads and other analysis methods. The resulting computer program is general, and was used without modification to solve a variety of contact problems

'Flu' syndrome associated with other systemic manifestations with once a month rifampicin in the treatment of multi-bacillary leprosy

Rifampicin, a potent bactericidal drug, has become an essential component of multidrug treatment regimens for tuberculosis and leprosy. One of the adverse reactions described following twice weekly or once weekly administration of rifampicin is the “‘Flu” syndrome (Sister Mary Aquinas et al 1972, Girling & Wallace 1971). This syndrome is immunological in nature and is often associated with the presence of circulating rifampicin - dependent anti-bodies (Riska & Mattson 1972, Proceedings of Workshop 1973). Initially it was thought to be uncommon with longer intervals between doses of the drug, i.e., once a month administration, as advocated in the chemotherapy of leprosy (WHO 1982). However, there have been a few reports about the occurrence of “Flu” syndrome with a regimen containing rifampicin once a mouth (Naafs & Matemera 1986, Parking & Shah 1989, Patki et al 1988, Vaz et al 1989). We report here three cases of leprosy developing “Flu” syndrome, associated with other systemic manifestations, during the monthly phase of their treatment

Measuring Mueller matrix of an arbitrary optical element with a fixed set of polarization optics

We have described a novel way to determine the Mueller matrix of any optical element by using projection method. For this purpose, we have used two universal SU(2) gadgets for polarization optics to obtain projection matrix directly from the experiment. Mueller matrix has been determined using the experimentally obtained projection matrix for three known optical elements namely free space, half wave plate and quarter wave plate. Experimental matrices are in good agreement with the corresponding theoretical matrices. The error is minimized as the experimental conditions remains same for all measurements since we have used a fixed set of polarization optics i.e. there is no removal or insertion of an optical component during the experiment.Comment: 8 pages, 1 figure and 1 tabl