Self-injection locking of DFB laser diode with Brillouin amplification in optical fibre feedback

A novel optical injection-locking configuration utilising Brillouin amplification in optical fibre feedback is reported. The proposed structure exhibits properties inherent in two phenomena, self-injection locking and injection-locking in master-slave configuration at the same time. Significant narrowing of the locked DFB laser linewidth was recorded. The configuration provides intensity-stable Stokes generation without a high-frequency external modulator and generator.     

Parameters and Technology for Fabricating PIK Reactor Fuel Elements

The construction of the fuel elements of a high-flux PIK research reactor is described. The technological tolerances in the process of fuel-element fabrication are presented. The basic geometric and mass parameters of several standard batches of fabricated fuel elements are determined experimentally. Statistical analysis of the experimental data shows that the deviations in the main parameters fall within the limits of the indicated technological tolerances and are described by a Gaussian distribution to a high degree of accuracy.     

On the optimization of metal forming

An approach to the calculation and design of metal forming is proposed and theoretically considered. This approach can minimize the nonuniformity of a deformation distribution over the cross section of ready products, which is equal to controlling the structure and properties of forged pieces. This approach is based on the calculation of the intermediate shapes of a forged piece by solving a set of inverse forming problems using the boundary element method and by constructing a forging process that is optimal according to a given criterion using dynamic programming.     

Technological prediction as a means of identifying additional competitive advantages of a specific production process

Results are presented from predictions of the quality indices of metal products used in critical applications. The predictions are obtained for combinations of technological factors that are not used in the actual production process. The reliability of the predictions is confirmed by the fact that the index values obtained with the use of regression models agree with the values obtained using corresponding genetic algorithms. The advantages of the methodology described in the article are demonstrated using the example of analysis of the multi-stage cold rolling of tubes made of zirconium alloys. The introduction of procedures for making technological predictions will help make production processes more efficient and, thus, more competitive. __________ Translated from Metallurg, No. 2, pp. 31–36, February, 2007.     

Effect of vitamins A, E and K on the indices of the glutathione antiperoxide system in gingival tissues in periodontosis

Glutathione reductase is activated and the content of glutathione sulfhydryl groups is increased in the gingival tissue of patients afficted with parodontosis. The degree of alterations depends on the degree of the development and character of the disease. Application of antioxidant vitamin therapy (vitamins A, E and K) locally and per os normalizes the parameters under study and improves the status of the parodontium.     

Similarity and symmetry measures for convex shapes using Minkowskiaddition

This paper is devoted to similarity and symmetry measures for convex shapes whose definition is based on Minkowski addition and the Brunn-Minkowski inequality. This means, in particular, that these measures are region-based, in contrast to most of the literature, where one considers contour-based measures. All measures considered in this paper are invariant under translations; furthermore, they can be chosen to be invariant under rotations, multiplications, reflections, or the class of affine transformations. It is shown that the mixed volume of a convex polygon and a rotation of another convex polygon over an angle &thetas; is a piecewise concave function of &thetas;. This and other results of a similar nature form the basis for the development of efficient algorithms for the computation of the given measures. Various results obtained in this paper are illustrated by experimental data. Although the paper deals exclusively with the two-dimensional case, many of the theoretical results carry over almost directly to higher-dimensional spaces     

A D&T roundtable: challenges for low-power and high-performancechips

Microprocessor and other lC performance continues to improve at historic rates, with no visible end in sight for the next 10 years. However, we are starting to encounter a power wall. This is true for high-performance components as well as for low-power chips with a very limited energy budget offered by batteries. We need to find ways to manage power and energy consumption on all fronts-technology, design, and architecture-without compromising performance. Otherwise, we may face discontinuation of Moore's law for the semiconductor industry in the near future. This would be triggered not by any difficulty in the scaling of process technology but by formidable barriers posed by packaging and cooling, inefficacy of power delivery, and energy constraints dictated by battery technology, which is advancing at a very lukewarm pace