Effect of nano-carbon dispersions on signal in silicon-based sensor structure with photoelectrical transducer principle

We identified different nano-carbon species such as graphene nanoplatelets, graphite flakes and carbon nanotubes dispersed in N-methyl-2-pyrrolidone using a novel sensor structure based on a “deep” silicon barrier working as a photoelectrical transducer. Each nano-carbon particle has specific signature in both 2D photocurrent distribution and photocurrent dependencies on bias changing surface band-bending. Additionally, all nano-carbon particles have characteristic features in the time-dependent evolution of photocurrent. The obtained results can be explained by the influence of nano-carbon molecules' local electric field on the recombination parameters of defect centers on the silicon surface.     

Sedimentation of particles in shear flows of viscoelastic fluids with fibers

We study the effect of fiber additives on rheology and sedimentation of particle suspensions in a base viscoelastic suspending fluid in the case when the suspension is subjected to shear flow. We found experimentally that fiber additives (3–6 mm in length and 8–12 μm in diameter at a mass fraction of 0–0.4%) increase the suspension viscosity and retard the particle sedimentation significantly. At the same mass concentration, long and thin fibers reduce the sedimentation velocity and increase the viscosity to a much greater extent than short and thick fibers. We revealed that both rheology and sedimentation are controlled by a single conformational parameter (overlap parameter) defined as the number of fibers per unit volume multiplied by fiber length cubed.     

Synthesis and properties of As<Subscript>x</Subscript>Te<Subscript>100−x</Subscript> films prepared by plasma deposition via elemental As and Te

As_xTe_100?x chalcogenide films (where x = 30–80 at.%) were synthesized via direct interaction of arsenic and tellurium vapors into low-temperature non-equilibrium RF (40 MHz) plasma discharge at reduced pressure. Phase and structural evolution of As_xTe_100?x films were implemented by gradual changing of the ratio of the initial substances in the gas phase. The dependence of the films structure, surface morphology and optical properties on phase and chemical content has been studied.     

Photonic bandgap examination in an immersed synthetic opal

We inspected photonic bandgap (stop-zone) in a synthetic opal (photonic crystal) immersed with different liquids. Dependences of the bandgap depth and spectral position on the immersed liquid refractive index were measured in the case of normal light incidence to the (111) face. An explanation of the observed spectral displacement of the bandgap is given on the basis of interaction between forward-propagating wave affected by Bragg diffraction and phase-shifted back-scattered wave.     

Total synthesis of indole-derived allocolchicine analogues exhibiting strong apoptosis-inducing activity

A series of novel pyrrolo-allocolchicine derivatives (containing a 1-methyl-1H-indol-5-yl moiety replacing ring?C) was synthesized. The tetracyclic ring system was constructed by Suzuki-Miyaura cross-coupling of a 1-methylindole-5-boronate with an ortho-iodo-dihydrocinnamic acid derivative and subsequent intramolecular Friedel-Crafts acylation. After reduction of the resulting ketone, the nitrogen functionality was introduced in a Mitsunobu-type reaction by using zinc azide followed by LiAlH(4) reduction. Structural assignments were supported by X-ray crystallography. The compounds synthesized were then tested against BJAB tumor cells and found to exhibit pronounced cytotoxic activity (proliferation inhibition and apoptosis induction). The ketone 24?b was even active at sub-nanomolar concentration. In addition, the antitumor potential of the compounds was confirmed by using B lymphoid cell lines.     

Angular Averaged Profiling of the Radial Electric Field in Compensated FTICR Cells

A recent publication from this laboratory reported a theoretical analysis comparing approaches for creating harmonic ICR cells. We considered two examples of static segmented cells--namely, a seven segment cell developed in this laboratory and one described by Rempel et al., along with a recently described dynamically harmonized cell by Boldin and Nikolaev. This conceptual design for a dynamically harmonized cell has now been reduced to practice and first experimental results obtained with this cell were recently reported in this journal; this publication reported details of cell construction and described its performance in a 7 tesla Fourier transform mass spectrometer. We describe the extension of theoretical analysis creating harmonic ICR cells to include angular-averaged radial electric field calculations and a discussion of the influence of trapping plates.     

Crytal and molecular structure of hydrido(trichlorostannyl)bis-cyclopentadienyl molybdenum(η5-C5H5)2Mo(H)SnCl3

On the basis of X-ray analysis the crystal and molecular structures of (η₅-C₅H₅)₂Mo(H)SnCl₃ have been determined. The compound crystallizes in the monoclinic system with parameters: a = 8.313(3), b = 13.109(4), c = 6.384(2) Å, β = 106.52(2)°, space group P2₁/m, R = 0.028. The conformation occurring in Cp₂Mo(H)SnCl₃ is that with the maximum repulsion between the chloride atoms and the cyclopentadienyl rings. The hydride H atom is shielded by the cyclopentadienyl groups and chlorine atoms, which accounts for the compound's stability to oxygen and hydrolysis.     

Energy-efficient dehydrogenation of methanol in a membrane reactor: a mathematical modeling

A two-dimensional non-isothermal stationary mathematical model of the catalytic membrane reactor for the process of methanol dehydrogenation is described. Copper supported on the carbonaceous support was considered as a catalyst. The reaction of methanol dehydrogenation was thermodynamically conjugated with a reaction of hydrogen oxidation taking place in a shell side of the membrane reactor. The effects of various parameters on the methanol conversion and the methyl formate yield have been calculated with the developed model and discussed. Two different types of heating the gas flow were considered and compared. In the case of conjugated dehydrogenation process, the methyl formate yield reaches 77%, when the reactor outer wall was heated up to 150 °C. When the inlet gas flows in the tube and shell sides were heated up to 100 and 83 °C, correspondingly, the yield was 72%.