Halogen bonds in 2D supramolecular self-assembly of organic semiconductors

Weak interactions between bromine, sulphur, and hydrogen are shown to stabilize 2D supramolecular monolayers at the liquid-solid interface. Three different thiophene-based semiconducting organic molecules assemble into close-packed ultrathin ordered layers. A combination of scanning tunneling microscopy (STM) and density functional theory (DFT) elucidates the interactions within the monolayer. Electrostatic interactions are identified as the driving force for intermolecular BrBr and BrH bonding. We find that the SS interactions of the 2D supramolecular layers correlate with the hole mobilities of thin film transistors of the same materials.     

Formic Acid Production Via Methane Peroxide Oxidation Over Oxalic Acid Activated Fe-MFI Catalysts

Topics in Catalysis - The process of synthesis of formic acid via partial peroxide oxidation of methane over Fe-MFI zeolites, as well as the influence of the catalyst activation by oxalic acid on...     

Verification of the boundaries of the applicability of the holm approximation for the calculation of the resistance of electric contacts

This paper presents the computation results for the passage of a current through electrodes of various shapes. In particular, cylindrically shaped contacts and rectangular current-carrying buses are considered. The effect of the electrode boundaries and the location of the contact spots on the value of the contact resistance was estimated. It was shown when the contact resistance can admittedly differ from the values found using the available analytical formulas.     

Thermal denaturation and aggregation of Myosin subfragment 1 isoforms with different essential light chains

We compared thermally induced denaturation and aggregation of two isoforms of the isolated myosin head (myosin subfragment 1, S1) containing different "essential" (or "alkali") light chains, A1 or A2. We applied differential scanning calorimetry (DSC) to investigate the domain structure of these two S1 isoforms. For this purpose, a special calorimetric approach was developed to analyze the DSC profiles of irreversibly denaturing multidomain proteins. Using this approach, we revealed two calorimetric domains in the S1 molecule, the more thermostable domain denaturing in two steps. Comparing the DSC data with temperature dependences of intrinsic fluorescence parameters and S1 ATPase inactivation, we have identified these two calorimetric domains as motor domain and regulatory domain of the myosin head, the motor domain being more thermostable. Some difference between the two S1 isoforms was only revealed by DSC in thermal denaturation of the regulatory domain. We also applied dynamic light scattering (DLS) to analyze the aggregation of S1 isoforms induced by their thermal denaturation. We have found no appreciable difference between these S1 isoforms in their aggregation properties under ionic strength conditions close to those in the muscle fiber (in the presence of 100 mM KCl). Under these conditions kinetics of this process was independent of protein concentration, and the aggregation rate was limited by irreversible denaturation of the S1 motor domain.     

2-methyl-2-butene production using positional isomerization catalyzed by sulfonic acid cation exchangers

Economically efficient 2-methyl-2-butene production is an essential element of the promising isoprene manufacturing process using 2-methyl-2-butene epoxidation and the dehydration of the resulting epoxide. An efficient way of producing 2-methyl-2-butene is isopentane dehydrogenation followed by 2-methyl-2-butene recovery from the resulting C5 fraction by liquid-phase isomerization (preferably on sulfonic acid cation exchangers) and distillation.     

Urgent Problems of Creation and Commercial Use of Corrosion-Resistant Ferritic Steels with Special Physical Properties

Metal Science and Heat Treatment -     

Modelling of orthogonal cutting processes with the method of smoothed particle hydrodynamics

In the last decades, mesh-free methods for simulating various cutting processes have been used very widely as they can eliminate numerical problems in the simulation of material failure and large plastic deformations. This paper deals with the results from modelling the orthogonal cutting of AISI 1045 steel using smoothed particle hydrodynamics (SPH) method. Moreover, it is determined how the parameters of the SPH solver such as initial smoothing length, initial particle density and coefficient for the timestep increase affect the prediction error for the values of cutting force and chip compression ratio as well as computing time. The optimum values of the SPH solver parameters are determined by minimising an objective function. The best balance between the prediction error of machining variables and computing time is achieved for an initial particle density of 40 μm and a coefficient for the timestep increase of 0.4.     

First-level Dulkyn gravitational wave detector

The functional-block diagram of the Dulkyn gravitational wave detector is described.     

The electronic educational resource “Dynamics of Systems for Controlling Thermal Processes”

We present the results from the development of a cycle of tutorial laboratory works for remote education under the general title “Dynamics of Systems for Controlling Thermal Process” for students specializing in the discipline of automation of technological processes and production facilities worked out on the basis of the Matlab software package and the Simulink environment for development of simulation models.     

Improving the technology used to make steel for side members

Conclusions  Statistical methods were used to study the effect of the mass content of different chemical elements on the level of the mechanical properties of normalized universal plates of steel 20GYuT. Multiple correlation equations were obtained and can be used to predict the strength and ductility characteristics of rolled products of steel 20GYuT with a probability of 0.85 in relation to the mass contents of carbon, manganese, and titanium determined from chemical analysis of ladle samples. A study was made of the feasibility of making side-member steel with a mass content of manganese below the level specified by the standard TU14-1-4632-93 (1.0–1.14%). It was established that normalization of heats with a mass content of manganese of 1.0–1.14% produces the specified set of mechanical and service properties as long as the mass content of carbon in the steel is at least 0.19%. To ensure that the required set of mechanical and service properties is obtained, it is recommended that steel 20GYuT be made with a carbon content of 0.19–0.23%, a manganese content of 1.0–1.3%, and a titanium content of 0.10–0.14%. The recommended chemical composition of steel 20GYuT and the heat-treatment regimes that have been developed for rolled plates of this steel will make it possible to do the following: