Thermomagnetic data writing and erasing in DyCo/NiFe (TbFe/NiFe) film structures

A new principle of data writing and erasing is proposed based on the exchange coupling between magnetic layers with mutually orthogonal orientations of the effective magnetization. The new method provides for a significant decrease in energy consumption. The possibility of using bilayer magnetic films of the (rare earth metal-transition metal)/NiFe type possessing unidirectional anisotropy as the media for thermomagnetic writing and erasing of magnetooptical data is studied.     

Providing quality of service over a shared wireless link

We propose an efficient way to support quality of service of multiple real-time data users sharing a wireless channel. We show how scheduling algorithms exploiting asynchronous variations of channel quality can be used to maximize the channel capacity (i.e., maximize the number of users that can be supported with the desired QoS)     

Starch-Coated Magnetic Iron Oxide Nanoparticles for Affinity Purification of Recombinant Proteins

Starch-coated magnetic iron oxide nanoparticles have been synthesized by a simple, fast, and cost-effective co-precipitation method with cornstarch as a stabilizing agent. The structural and magnetic characteristics of the synthesized material have been studied by transmission electron microscopy, Mössbauer spectroscopy, and vibrating sample magnetometry. The nature of bonds between ferrihydrite nanoparticles and a starch shell has been examined by Fourier transform infrared spectroscopy. The data on the magnetic response of the prepared composite particles have been obtained by magnetic measurements. The determined magnetic characteristics make the synthesized material a good candidate for use in magnetic separation. Starch-coated magnetic iron oxide nanoparticles have been tested as an affinity sorbent for one-step purification of several recombinant proteins (cardiac troponin I, survivin, and melanoma inhibitory activity protein) bearing the maltose-binding protein as an auxiliary fragment. It has been shown that, due to the highly specific binding of this fragment to the starch shell, the target fusion protein is selectively immobilized on magnetic nanoparticles and eluted with the maltose solution. The excellent efficiency of column-free purification, high binding capacity of the sorbent (100–500 µg of a recombinant protein per milligram of starch-coated magnetic iron oxide nanoparticles), and reusability of the obtained material have been demonstrated.     

On the Temperature Dependence of the Viscosity of Multicomponent Glasses in the Glass Transition Range

The viscosities of eight optical glasses are measured in the vicinity of the glass transition temperature (450–680°C, 10¹¹–10¹² P). It is demonstrated that the Shishkin and Williams–Landell–Ferry equations are applicable in the temperature range under investigation. The parameters of the fluctuation free volume concept are calculated. The physical meaning of these parameters is discussed.     

Mass Spectrometric Study of the Thermodynamic Properties of Melts in the CaO–TiO2–SiO2 System

The composition of the vapor over melts in the CaO–TiO₂–SiO₂ system, activities of the melt components, and Gibbs energies of formation are determined by high-temperature mass spectrometry upon evaporation from tungsten cells in the temperature range 1800–2200 K. It is demonstrated that the positive deviation of the SiO₂ activity from ideal behavior in melts of the CaO–TiO₂–SiO₂ system at constant mole fraction ratios CaO/TiO₂ equal to 2.33 and 1.5 is caused by the presence of titanium dioxide. The SiO₂ activity decreases in the case when CaO is added to SiO₂ and increases when TiO₂ is introduced into the system under investigation.     

Vaporization and Thermodynamic Properties of Melts in the Na2O–B2O3–SiO2 System

The vapor composition, partial pressures of the molecular species of the vapor, and activities of the melt components in the Na₂O–B₂O₃–SiO₂ system at temperatures of 1300 and 1350 K are studied using the Knudsen effusion mass-spectrometric method. It is shown that the vapor composition depends on the concentration ratio of sodium and boron oxides in the condensed phase. When the content of boron oxide is larger than the content of sodium oxide in the condensed phase, the vapor contains NaBO₂, (NaBO₂)₂, and B₂O₃ molecules. At the ratio [Na₂O] : [B₂O₃] > 1, the gas phase contains atomic sodium. The activities obtained for NaBO₂ and B₂O₃ indicate substantial negative deviations from an ideal behavior.     

Magnetite Nanocrystals with a High Magnetic Anisotropy Constant due to the Particle Shape

Technical Physics Letters - Chemical solution deposition in the presence of arabinogalactan makes it possible to prepare magnetite nanocrystals in the form of square plates with a high aspect ratio...