Improving the technology used to make welded carbon-steel tubes

Electric-welded tubes made of carbon steels are less expensive, have a better-quality surface, and have more accurate dimensions than equivalent seamless tubes. An efficient method has been proposed for making the distribution of the strains and residual stresses in such tubes more uniform about their perimeter (and reducing the stress level in general). The method employs cold reduction in the final passes of the forming mill, which has a closed pass. Similar reductions are also made in the welding and guide stands. The authors constructed a model to control the voltage on the induction coil, and they determined the dependence of temperature in the welding zone on the length of the edges in the welding gap. The introduction of new tube-production methods and equipment developed as part of this research has made it possible to master the industrial production of new types of special-use tubes, tubes with fewer or no internal burrs, and tubes with stronger welds, better mechanical characteristics, and other improved quality indices. __________ Translated from Metallurg, No. 5, pp. 63–67, May, 2006.     

Ga(In)AsP Lateral Nanostructures as the Optical Component of GaAs-Based Photovoltaic Converters

Semiconductors - The possibility of using lateral Ga(In)AsP nanostructures grown by the catalytic method in a quasi-closed volume from phosphorus and indium vapors on the GaAs (100) surface as an...     

A digital correlation speckle shift interferometer

The optical circuit of a speckle shift interferometer with two arms of different lengths is presented and its operating principle described. The device includes a semiconductor laser that serves as the radiation source and a digital camera interfaced to a computer.     

Few-view gamma tomography used to monitor scabbing and shear fracture in a spherical iron shell compressed by explosion

The effectiveness of few-view gamma tomography for nondestructive testing of the internal structure of scabbing and shear fracture in a spherical iron shell subjected to explosive compression has been studied experimentally. To obtain shadow X-ray radiograms of the shell, a fine-focus betatron and a screened photographic film are used. The results of reconstruction performed by applying a modified multiplicative algebraic reconstruction technique and subsequent postprocessing of tomograms of a meridional section of the compressed shell are considered. It is shown that the precision of reconstruction of the spatial pattern of fractures mostly depends on the number of projections used during the experiment.     

The effect of ultrasound on the parameters of metal-dielectric-semiconductor structures

Data on the effect of ultrasound on the metal-oxide-semiconductor structures preliminary irradiated by γ-quanta are presented. It is demonstrated that the ultrasonic action results in a decrease of the radiation-induced charge in the dielectric layer of the structures under study. The observed effects are explained using a mechanism of the ultrasound-stimulated diffusion of radiation defects in the field of elastic stresses in the layer of silicon dioxide.     

Ultrahigh-Bandwidth Silicon Photonic Nanowire Waveguides for On-Chip Networks

An investigation of signal integrity in silicon photonic nanowire waveguides is performed for wavelength-division-multiplexed optical signals. First, we demonstrate the feasibility of ultrahigh-bandwidth integrated photonic networks by transmitting a 1.28-Tb/s data stream (32 wavelengths times 40-Gb/s) through a 5-cm-long silicon wire. Next, the crosstalk induced in the highly confined waveguide is evaluated, while varying the number of wavelength channels, with bit-error-rate measurements at 10 Gb/s per channel. The power penalty of a 24-channel signal is 3.3 dB, while the power penalty of a single-channel signal is 0.6 dB. Finally, single-channel power penalty measurements are taken over a wide range of input powers and indicate negligible change for launch powers of up to 7 dBm.     

Detonation synthesis of a new modification of aluminum oxide from gibbsite by explosion

The x-ray diffraction analysis of the condensed products resulting from explosion of gibbsite — hexogen mixtures was carried out. It was established that in explosion of the mixture, along withα-Al₂O₃, another, previously unknown modification of aluminum oxide is formed in nearly the same amount. The x-ray diffractometric data of the new modification are presented.     

Synthesis of FeAl2O4 under a shock-wave effect

FeAl₂O₄ is synthesized under the effect of shock-wave impact on gibbsite placed in a steel preservation ampoule. The type and parameters of the unit cell of this compound are determined. The x-ray patterns of the condensed products obtained on shock-wave impact are presented.