Influence of deposition parameters on hole mobility in polymorphous silicon

Time-of-flight transient photoconductivity measurements reveal a monotonic increase with the deposition pressure in the hole mobility in polymorphous silicon for samples deposited under hydrogen dilution. With helium dilution, a maximum mobility that matches the highest value from H-dilution samples is measured at the intermediate pressure of 1.4 Torr. The deposition rate of those samples is twice the rate for the H-dilution ones. For the samples with the best hole mobilities, the valence-band tail is comparable to the one of standard hydrogenated amorphous silicon.     

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.     

A PTAS for Cutting Out Polygons with Lines

We present a simple O(m+n ⁶/ε ¹²) time (1+ε)-approximation algorithm for finding a minimum-cost sequence of lines to cut a convex n-gon out of a convex m-gon.     

New Results on Path Approximation

In this paper we give bounds on the complexity of some algorithms for approximating 2-D and 3-D polygonal paths with the infinite beam measure of error. While the time/space complexities of the algorithms known for other error measures are well understood, path approximation with infinite beam measure seems to be harder due to the complexity of some geometric structures that arise in the known approaches. Our results answer some open problems left in previous work. We also present a more careful analysis of the time complexity of the general iterative algorithm for infinite beam measure and show that it could perform much better in practice than in the worst case. We then propose a new approach for path approximation that consists of a breadth first traversal of the path approximation graph, without constructing the graph. This approach can be applied to any error criterion in any constant dimension. The running time of the new algorithm depends on the size of the output: if the optimal approximating path has m vertices, the algorithm performs F(m) iterations rather than n–1 in the previous approaches, where F(m) \le n–1 is the number of vertices of the path approximation graph that can be reached with at most m–2 edges. This is the first output sensitive path approximation algorithm.     

Self-propagating high-temperature synthesis of boron subphosphide B12P2

Two new methods to produce nanopowders of B₁₂P₂ boron subphosphide by self-propagating high-temperature synthesis have been proposed. Bulk polycrystalline B₁₂P₂ with microhardness of H _V = 35(3) GPa and stability in air up to 1300 K has been prepared by sintering these powders at 5.2 GPa and 2500 K.     

Development of a hybrid ECT sensor for JSFR SG double-wall tubes

A new design has been adopted for the steam generator (SG) tubes of the Japan Sodium-cooled Fast Reactor (JSFR) using double-wall tubes. This paper estimates and assesses the effectiveness of detecting defects in SG double-wall tubes of the JSFR by using combined high-frequency eddy current testing (ECT) and low-frequency remote field eddy current sensors. We confirm that the proposed hybrid ECT sensor is highly sensitive to small defects, fatigue cracks, and other defects even when located under support plates of tubes. The parameters of the hybrid ECT sensor are designed and optimized to detect small defects using accurate numerical simulations based on the finite element method, using an in-house developed code. The sensitivity and high performance of the hybrid ECT sensor was validated with experimental measurements.     

Molecularly imprinted poly(acrylonitrile‐co‐acrylic acid) matrix with sclareol

There are presented results regarding a new set of molecularly imprinted polymers (MIPs) based on acrylonitrile:acrylic acid (AN:AA) copolymer matrix. As template, it was used sclareol, an important anticancer bioactive compound, never used before for molecular imprinting. An emerging and insufficient studied MIP preparation method, namely the phase inversion, was used to prepare 0.8 mm spherical sclareol MIPs (S‐MIPs). Three AN:AA copolymers, having the initial monomer ratios 90:10, 80:20, and 70:30, were synthesized by radical copolymerization in emulsion, without emulsifier. After that, each copolymer was dissolved in the presence of the template (sclareol) in dimethylformamide. The imprinting and the morphology of these new materials were analyzed by rheology, elemental analysis, infrared spectroscopy, size exclusion chromatography, thermogravimetric analysis, differential scanning calorimetry, batch rebinding tests, and Scatchard analysis. The conclusion was that the AN:AA‐80:20 matrix proved to be the optimized solution between high rigidity (given by the AN segments) and high affinity for the template (given by AA segments), the average imprinting factor for this system being 2.67. POLYM. ENG. SCI., 54:1484–1494, 2014. © 2013 Society of Plastics Engineers     

The dependence of the photocatalytic activity of TiO2/carbon nanotubes nanocomposites on the modification of the carbon nanotubes

Nanostructural TiO₂/modified multi-wall carbon nanotubes photocatalysts were prepared by hydrolysis of Ti(iso-OC₃H₇)₄ providing chemical bonding of anatase TiO₂ nanoparticles onto oxidized- or amino-functionalized multi-wall carbon nanotubes (MWCNT). The processes of functionalization of the MWCNT and the deposition of TiO₂ influence the photocatalytic activity of the synthesized nanocomposites. The phase composition, crystallite size, and the structural and surface properties of the obtained TiO₂/modified-MWCNT nanocomposite were analyzed from XRD, FEG-SEM, TEM/HRTEM and FTIR data, as well low temperature N₂ adsorption. In the photocatalytic study, the TiO₂/oxidized-MWCNT catalyst showed the highest and the TiO₂/amino functionalized-MWCNT catalysts somewhat lower degradation rates, indicating that the enhancement of photocatalysis was supported by the more effective electron transfer properties of the oxygen- than amino-containing functional groups, which support the efficient charge transportation and separation of the photogenerated electron-hole pairs.     

Generalization of information on phase diagrams of binary hafnium systems

Prospects of applying the analogy principle when investigating binary hafnium compounds are considered. The classification of binary hafnium compounds by the main distinctive features of their phase diagrams is developed using a taxonomic approach. Seven uniform groups of compounds under consideration are distinguished and distinctive features of phase diagrams of each group are determined. The rationality of a two-dimensional metric, the application of which ensures obtaining qualitative evaluations of similarity of various diagrams and reveals the analog compounds, is substantiated. The results of classification can be used when substantiating the compositions of certain basic hafnium alloys and master alloys.