Formation of small volatile complexes during copper film growth by the combined synthesis-transport method

Stable heterogeneous synthesis products in combined synthesis-transport processes for the growth of thin copper films have been studied by ESR, X-ray photoelectron, and IR spectroscopies. The results demonstrate that the synthesized volatile compounds condensed on solid surfaces have the form of formate-like metal complexes of copper(I). We have identified the mechanisms underlying the formation of volatile monomeric metal complexes on the surface of copper-containing precursor particles and the mechanism of the thermal decomposition of metal complexes on a heated substrate.     

Application of super-resolution techniques to expert testing of welded joints in pipelines of nuclear power plants

Utilization of super-resolution techniques in processing reflected signals in ultrasonic testing has proved to be useful with a view to improve expert estimates of defect dimensions and shapes with the help of theAvgur holographic facility. In particular, the improvements in the image quality mostly due to athree-fold increase in the beam coordinate resolution has allowed more accurate determination of defect dimensions and more reliable classification of defects.A lower intensity of the speckle noise due to the broader frequency band can also be considered as a favorable feature of the extrapolation techniques. The signal-to-noise ratio in the images of flaws in materials with an intense structural noise isa factor of about 1.7 higher when super-resolution techniques are used. The paper describes some results of practical utilization of super-resolution techniques in estimating dimensions of flaws detected in welded joints of DU-300 pipelines (an effective diameter of 300 mm) of nuclear power plants.     

What acoustic holography can do

The history of development of acoustic holography in Russia is outlined. Examples of its efficient applications are given.     

Plasma Deposition and Properties of Silicon Carbonitride Films

A variety of advanced analytical techniques were used to characterize silicon carbonitride films grown from new volatile nitrogen-rich silyl derivatives of asymmetrical dimethylhydrazine: (CH₃)₂HSiNHN(CH₃)₂ (DMDMSH) and Me₂Si(NHNMe₂)₂ (bisDMHDMS). The results demonstrate that the films contain only Si-C, Si-N, and C(sp ³)-N bonds, in relative amounts that depend on the molecular structure of the precursor and deposition conditions. The Si-C/[Si-N + C(sp ³)-N] ratio is considerably larger in the films grown from DMDMSH. The data obtained by a variety of spectroscopic techniques provide solid evidence that some of the films contain C(sp ³)-N bonds, characteristic of superhard materials, and that the films have a complex, framework structure, rather than being a mixture of Si₃N₄, SiC, and C₃N₄. The structure of the films depends on the N : Si ratio in the precursor: at N : Si = 2, the films are amorphous and contain nanocrystalline inclusions with a tetragonal structure; at N : Si = 4, the films are purely amorphous. The ability to control the chemical composition and structure of deposits allowed us to produce films with various physicochemical and electrical properties.__________Translated from Neorganicheskie Materialy, Vol. 41, No. 7, 2005, pp. 808–815.Original Russian Text Copyright © 2005 by Smirnova, Badalyan, Borisov, Kaichev, Bakhturova, Kichai, Rakhlin, Shainyan.     

Efficient second-harmonic generation in a double-quantum-well structure

Second-harmonic generation in a double-quantum-well nanostructure is analyzed. Optimization of the structure design from the viewpoint of attaining the highest intensity of the second-harmonic wave at the output is considered. Relationships between the quantum-well parameters in a structure satisfying the double-resonance condition are established. The dependence of the optical characteristics of the system on the quantum-well parameters is studied and the problem of optimization of the second-harmonic intensity is solved. It is demonstrated that the highest conversion efficiency is attained under the conditions where the second-harmonic generation coefficient is maximum.     

An Inter-cluster Communication based Energy Aware and Fault Tolerant Protocol for Wireless Sensor Networks

The ambient intelligence paradigm is built upon Ubiquitous Computing (UC), in which the computing devices are embedded in the environment with the purpose of enhancing the human experience at home, workplace/office, learning, health care etc. The UC applications aim at providing services to the users anywhere, anytime in an unobtrusive, seemingly invisible way. Wireless sensor networks (WSNs) have great potential for UC applications and are envisioned to revolutionize them. This paper presents a clustering routing protocol for event-driven, query-based and periodic WSNs. The protocol aims at optimizing energy dissipation in the network as well as providing network’s fault tolerance and connectivity. Message propagation is accomplished by using short distance transmissions by employing nearest neighbor nodes between neighboring clusters. Moreover, the algorithm proposes using an energy efficient approach by alternating the nodes responsible for inter-cluster communication inside one cluster. The algorithm also aims at even energy dissipation among the nodes in the network by alternating the possible routes to the Sink. This helps to balance the load on sensor nodes and increases the network lifetime, while avoiding congested links at the same time. We discuss the implementation of our protocol, present its proof of correctness as well as the performance evaluation through an extensive set of simulation experiments. This work is partially sponsored by Grants from the NSERC, Canada Research Chairs Program, ORNEC, the Ontario Distinguished Researcher Award and the EAR Award.     

A noncavity scheme of optical detection of high-frequency magnetic and cyclotron resonances in semiconductors and nanostructures

To perform optical detection of high-frequency magnetic resonance (ODMR) and cyclotron resonance (ODCR) with a spatial resolution, we have proposed a noncavity scheme of an ODMR-ODCR spectrometer using a quasi-optical microwave channel. The efficiency of this scheme for obtaining information on the spin properties of ZnO quantum dots and CdMnTe quantum wells and on the effective masses of carriers in crystalline silicon films with a spatial resolution within a focused laser beam is illustrated.