Multiparameter Polynomial Adaptive Stabilizers

In 1983 Morse proved, for unknown scalar one-dimensional linearsystems, the nonexistence of rational or polynomial universalstabilizers (UAS). In 1983, Nussbaum gave an example of an analyticUAS. In our paper, it is shown that there exist time-invariantpolynomial UAS's with multidimensional gain adaptation. Thedesign procedure is developed for linear, minimum-phase systemsof relative degree one. Convergence of the closed-loop systemis proved. Some numerical simulations are provided.     

Insertion of 3d- and 4f-Elements into Silver Iodide

The interaction of manganese and some 4f-metals (M) with silver iodide is studied. The samples are obtained by sputtering M onto the surface of polycrystalline AgI films (0.2 m, 300 K) in a vacuum. Optical absorption in the samples is interpreted as the insertion of M ions into AgI with the formation of dopants AgI:M. A new phase with an optical bandgap of 3.7 eV emerges in the samples with elevated concentrations of La, Ce, Pr, Nd, Sm, or Dy (n _M/n _Ag 0.1). X-ray diffraction patterns for such samples with Sm correspond to structures with large interfacial distances, for example, 0.99, 0.87, 0.76, and 0.67 nm. In air, AgI forms in the samples with a new phase; this process is hindered by the sputtered protective coatings. According to optical absorption data, X-ray diffraction, and local microanalysis the Mn insertion into AgI is followed by the formation of a new phase (2Ag:Mn:4I), which may belong with solid electrolytes Ag₂MI₄, where nonmagnetic M are known (Zn, Cd, Sn, Hg, Pb).     

The Reaction of Tin Tetracarbamates with Organyl Chlorosilanes: A Novel Synthetic Route Towards O-Silylurethanes

Russian Journal of General Chemistry - O-Silylurethanes have been synthesized in up to 87% yield via the reaction of tin tetracarbamates with organyl chlorosilanes in the presence of tertiary amines.     

A new ent-labdane eiterpenoid lactone from Andrographis paniculata

A new ent-labdane diterpenoid lactone with a new natural product was isolated from Andrographis paniculata. Their structures were elucidated on the basis of spectral evidences including 2D NMR.     

Asymmetric synthesis of pedamide using I_2-induced heterocyclization to construct the skeleton

An alternative approach to synthesize pedamide,a key building block of pederin was described.Iodine-induced asymmetric heterocyclization was used as the key step to construct the skeleton,a tetrahydropyran ring with three chiral centers.Brown's asymmetric allylation and Lewis acid-mediated allylation were investigated to introduce chains and chiral alcohols.Sharpless dihydroxylation decorated the side chain.And high optically pure target was obtained by removing the epimers formed in these reactions on c...     

Choice of temperature for safflower oil hydrolysis catalyzed by Candida rugosa lipase

This work studies safflower oil hydrolysis catalyzed by Candida rugosa lipase as a function of temperature in an oil-in-water emulsion stabilized by the surfactant sodium deoxycholate. The choice of temperature for this reaction is dictated by the effects of temperature not only on the catalytic activity and stability of the enzyme but also on the state of the reaction medium (emulsion), whose quality substantially affects both the kinetic parameters of lipase and the product (linoleic acid) yield. For example, although the highest initial rate of the enzymatic reaction is observed at 40°C and the enzyme is virtually not inactivated during incubation (45°C), the highest reaction yield is observed at 30°C and decreases upon temperature elevation because of a change in the emulsion quality.     

Phase transition in strongly degenerate hydrogen plasma

Direct fermionic path-integral Monte Carlo simulations of strongly coupled hydrogen are presented. Our results show evidence for the hypothetical plasma phase transition. Its most remarkable manifestation is the appearance of metallic droplets, which are predicted to be crucial for the electrical conductivity and allow one to explain the rapid increase found in recent shock compression measurements.     

Microwave-assisted one-pot synthesis of 3-substituted-3,4-dihydrocoumarins via tendem Konevenagel and Hantzsch reactions

A convenient route for the synthesis of 3,4-dihydrocoumarin derivates from salicylaldehyde derivates and 1,3-dicarbonyl compounds under solvent-free microwave irradiation conditions was described. In this way, a range of compounds was obtained in moderate to good yields in a short reaction time.     

Experimental Study of Ar-Gas Radiation Behind the Front of a Strong Shock Wave

Journal of Applied Spectroscopy - Emission spectra of argon behind the front of a strong shock wave are studied in the range of shock-wave velocities of 4.6–8.3 km/s and pressures before the...     

Thermodynamic coefficients of ideal Fermi gas

We present analytical formulae for the first and second derivatives of the Helmholtz free energy of non-relativistic ideal Fermi gas. Important thermodynamic quantities such as heat capacity, sound velocity, heat capacity ratio, and others are explicitly expressed through the derivatives. We demonstrate correct ideal Boltzmann gas and low-temperature Fermi gas asymptotes and derive corrections to thermodynamic functions for these limiting cases. Numerical computations of thermodynamic properties of ideal Fermi gas can be accurately performed using the developed freely available Python module ifg .