Thermally Induced Viscous Flow of Borophosphosilicate-Glass Thin Films on Stepped Surfaces,Part 2: Generalized Parameters for ULSI Glass Flow Characterization

New flow parameters termed flow effectiveness andthermal budgetare used for the characterization of the thermal flow of borophosphosilicate glass serving as a premetal dielectric in ULSI circuits. Their practical value is discussed. It is concluded that the approach proposed reduces the cost of measurement, facilitates the interpretation of measured data, works for both furnace and rapid thermal annealing, is applicable to ULSI gap filling as well as glass planarization, and enables one to optimize the annealing temperature for thin films of low-fusible multicomponent glasses.     

Artificial abortions in Bulgaria and their prevention

Authors go into one extremely important problem for the family, woman, natality and family planning in Bulgaria. Scarcely during the last years it can be observed a slight reduction of the frequency of induced abortions. The average age of women having an abortion is high--about 30, which shows, that induced abortion is still a method of regulation fertility in intergenetic interval. The rate of those who have induced abortion under the age of 19 in Bulgaria is 7.8 to 53.3%, in Czechoslovakia, 6.7%, in DDR--50.0%, Greece--68%, Hungary--8.9%, Sweden--15.8%. The rate of done again induced abortion is higher, that is a result of bad preventing activities during the first abortion. Similar is the tendency of growing number of unmarried women having an induced abortion, as it is in the other countries: from 16.4% in 1980 to 21.7% in 1987. Bulgaria is on the third place in Europe according to the absolute number of dead cases after abortion (maternity death, after Rumania and USSR). It can be mentioned that in Bulgaria women do not use the most modern and safest devices, medicines for interruption of pregnancy.     

Simulation of electron transport in GaAs/AlAs superlattices with a small number of periods for the THz frequency range

The electron transport in superlattices based on GaAs/AlAs heterostructures with a small number of periods (6 periods) is calculated by the Monte Carlo method. These superlattices are used in terahertz diodes for the frequency stabilization of quantum cascade lasers in the range up to 4.7 THz. The band structure of superlattices with different numbers of AlAs monolayers is considered and their current–voltage characteristics are calculated. The calculated current–voltage characteristics are compared with the experimental data. The possibility of the efficient application of these superlattices in the THz frequency range is established both theoretically and experimentally.     

Studying the properties and structure of polytetrafluoroethylene filled with Belum modified carbon fibers

The effect of Belum discrete carbon fibers on the service properties and structure of polytetrafluoroethylene has been studied. It has been shown that a filling of polytetrafluoroethylene with 1–5 wt % of carbon fibers does not worsen the stress–strain properties of composites. The introduction of carbon fibers improves the tribological characteristics of polytetrafluoroethylene. The thermodynamic and structural studied of polymer composites have been performed.     

Electrical conduction in plasma polymerized thin films of γ‐terpinene

Plasma polymerized γ‐terpinene (pp?GT) thin films are fabricated using RF plasma polymerization. MIM structures are fabricated and using the capacitive structures dielectric properties of the material is studied. The dielectric constant values are found to be in good agreement with those determined from ellipsometric data. At a frequency of 100 kHz, the dielectric constant varies with RF deposition power, from 3.69 (10 W) to 3.24 (75 W). The current density–voltage (J?V) characteristics of pp–GT thin films are investigated as a function of RF deposition power at room temperature to determine the resistivity and DC conduction mechanism of the films. At higher applied voltage region, Schottky conduction is the dominant DC conduction mechanism. The capacitance and the loss tangent are found to be frequency dependent. The conductivity of the pp?GT thin films is found to decrease from 1.39 × 10^?12 S/cm (10 W) to 1.02 × 10^?13 S/cm (75 W) and attributed to the change in the chemical composition and structure of the polymer. The breakdown field for pp–GT thin films increases from 1.48 MV/cm (10 W) to 2 MV/cm (75 W). A single broad relaxation peak is observed indicating the contribution of multiple relaxations to the dielectric response for temperature dependent J?V. The distribution of these relaxation times is determined through regularization methods. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42318.     

Real time observation of crystallization in polyethylene oxide with video rate atomic force microscopy

Video rate atomic force microscopy (VideoAFM), with a frame rate of 14 frames/s and a tip velocity of up to 15 cms⁻¹, is used to image polyethylene oxide films during crystal growth. The capabilities of VideoAFM when applied to semicrystalline polymer surfaces are explored. Image quality comparable to that found with conventional contact AFM is achieved but with a nearly 1000 times improvement in time resolution. By applying the technique to the real-time observation of crystal growth, different modes of rapid crystallization are followed in real time. Observation of the spherulite growth front allows measurement of growth rates at the lamellar scale, from which a factor of two difference in the rate of radial growth to the rate of tangential growth is observed, confirming that the elongated nature of spherulite lamellae is due to geometric constraints rather than an inherent fibrillar character. Measurements on screw dislocation growth, when large amounts of crystallizable material is trapped at the surface show that the terrace height does not influence the rate of crystal growth, confirming that under these conditions processes at the lamellar growth front control the rate of growth. When only a thin film of molten material is left on the surface of the already crystallized film dendritic growth is observed, implying a diffusion controlled process under these far from equilibrium conditions.     

Styryl dyes – synthesis and applications during the last 15 years

One of the most widely used and important groups of functional dyes are the styryl dyes and a review of this functional dye class has not been published for more than 15 years. In this review article, we describe the new trends in the synthesis of a range of novel intermediates and styryl dyes and include the most interesting examples of their high‐tech applications. However, this review is not intended to be comprehensive because of the large number of styryl dye studies that have been carried out in this time. Styryl cyanine dyes are widely used in optical recording media in laser discs, as flexible dyes, laser dyes, as optical sensitisers and in various other fields, for example dye‐sensitised solar cells and dyes with non‐linear optical properties. Additionally, the most important applications for these dyes are in bio‐labelling and in medicinal analysis.