Systems analysis of the viscoelasticity of polyester fibres

A comprehensive study of the mechanical properties of polyester fibres and other polymeric materials and prediction of deformation processes are only possible with systems analysis of the viscoelasticity of polymers. In determining the mechanical characteristics of polymeric materials and predicting the deformation processes that take place in them, selection of the mathematical model plays a role of no little importance. Although the deformation processes of one group of materials are more accurately predicted with one mathematical model, another mathematical model can be better for another group of materials. The broader the set of mathematical models and corresponding methods, the more accurately the mechanical characteristics of polymers can be determined and the more accurate the prediction of deformation processes will be. Both in selecting the mathematical model and in predicting the mechanical properties of polymeric materials, computerization of the calculations, which ensures reaching a higher level of investigation of the properties of the materials, plays a role of no little importance. __________ Translated from Khimicheskie Volokna, No. 1, pp. 62–65, January–February, 2007.     

The Thermoelectric Power of Bi1 –xSbx Films (0 ≤ x ≤ 0.15) on Mica and Polyimide Substrates in the Temperature Range of 77–300 K

Semiconductors - The results of an investigation into the thermoelectric power of thin block Bi1 –xSbx films (0 ≤ x ≤ 0.15) 100–1000 nm in thickness on mica and polyimide...     

Variation in resistance of a nitrogen-enriched silicon layer as a result of the long-range effect of ion implantation

An improvement in the insulating properties of a synthesized silicon nitride layer under the influence of ion-beam treatment of the back surface of silicon wafer was detected. This result is consistent with the infrared-spectroscopy data obtained previously and is related to the long-range effect of ion implantation.     

A comparative study of the chemical properties of element 120 and its homologs

The electronic structure and energetics were calculated for molecules of binary compounds of element 120 and its homologs with common elements strongly differing in chemical properties. The calculations were performed within the framework of the relativistic density functional theory using the model of precision two-component atomic core pseudopotentials. The results obtained show that all the examined compounds of element 120 should differ from the corresponding compounds of the known heavy metals of the second group (Sr-Ra) in lower strengths and larger lengths of chemical bonds. Therefore, one can suppose that element 120 will be, on the whole, more inert chemically than its nearest homologs.     

Determining the Granularity of Radiographic Films in Accordance with ISO 11699-1

Russian Journal of Nondestructive Testing - One of the important properties of industrial radiographic films that determine the clarity of the resulting image is granularity. In the technical...     

Silicon nanoprofiling with the use of a solid aluminum oxide mask and combined “dry” etching

Technological features of nanoprofiling of silicon protected by a solid mask based on porous aluminum oxide are considered. It is shown that, for a nanoprofiled silicon surface to be formed, it is advisable that combined dry etching be used including preliminary bombardment of structures with accelerated neutral atoms of an inert gas followed by reactive ion etching.     

Size effect in galvanomagnetic phenomena in bismuth films doped with tellurium

The results of experimental investigation of galvanomagnetic phenomena in single-crystalline and block films of tellurium-doped bismuth in the temperature range of 77–300 K and in the film-thickness range of 0.1–1 μm are presented. It is shown that the charge-carrier concentration in the investigated films is independent of thickness, the charge carriers are scattered at phonons, the film surface, structural defects, and crystallite boundaries. The values and ratio of the listed contributions to the restriction of charge-carrier mobility depend on the tellurium content, film thickness, and also their single-crystalline or block state.     

High-frequency heating and dynamic susceptibility of small La1 ? xAgyMnO3 + δ particles in the range of the magnetic phase transition

The nanoparticles of the lanthanum-silver manganites with the general formula La_{1 − x} Ag _y MnO_{3 + δ} (LAMO) that exhibit the Curie temperature T _C in the range 35…50°C, which is important for medical applications, are synthesized and studied. The heating kinetics of the LAMO aqueous suspensions under the action of the high-frequency (HF) magnetic field is experimentally studied and the self-stabilization in the vicinity of the Curie temperature is demonstrated. A sharp increase in the HF-absorption (specific absorption rate) is observed for the materials under study when approaching the Curie temperature from below. This effect is proven by direct measurements of the dynamic magnetic susceptibility in the critical range. The physical interpretations of the HF absorption are based on the hysteresis and oscillations of domain boundaries. It is demonstrated that the materials under study are promising for the medical hyperthermia with controlled heating temperature.     

A probe and amplifier of a <Emphasis Type="Italic">Q</Emphasis>-meter for recording electron paramagnetic resonances at 300 MHz

A probe with a high-frequency amplifier of a continuous-wave Q-meter-type electron paramagnetic resonance (EPR) spectrometer operating at 300 MHz is described. The probe is inductively connected with both an exciting high-frequency generator and the amplifier. The amplifier is matched to the probe for obtaining a minimum noise figure of 2.9 dB. The single-scan EPR line with a 1.7-G width and 3 × 10¹⁸ resonant paramagnetic centers is recorded with a signal-to-noise ratio of about 260.