Microwave spectra of mono-C substituted acetone, (CH3)2CO

The microwave spectra of the two mono-¹³C isotopic forms of acetone are reported for the first time. Measurements were carried out from 11 to 25 GHz with a pulsed-beam Fourier-transform microwave spectrometer. Because overall rotation interacts with the internal rotations of the methyl groups, the spectra were analyzed with an effective rotational Hamiltonian for molecules with two periodic large-amplitude internal motions. In acetone-2-¹³C, the methyl groups are equivalent; in acetone-1-¹³C, they are not. The molecular structure has been re-examined by including rotational constant data on other isotopic forms reported previously. An equilibrium structure for acetone has been derived from the observed rotational constants and vibration-rotation constants calculated from ab initio force fields.     

On the Contribution of Structural Relaxation to the Magnetic Softening During the Amorphous-Nanocrystalline Transformation

In the present paper the contribution of structural relaxation to the net magnetic softening will be treated taking place during the amorphous-nanocrystalline transformation. Isothermal heat treatments were carried out well below the crystallization, in the temperature range of (350-440)°C. Significant decrease of H _c and increase of permeability (50 Hz) can be found already due to these heat treatments. The beneficial role of stress relaxation (resulting from low heating rates) can be also detected in the resulting permeability at 50 Hz.     

Quantum chemical quantification of weakly polar interaction energies in the TC5b miniprotein

The tertiary structure of the TC5b miniprotein is stabilized by inter-residue interactions of the Trp-cage, which is composed of a Tyr and several Pro residues surrounding a central Trp residue. The interactions include Ar-Ar (aromatic side-chain-aromatic side-chain), Ar-NH (aromatic side-chain-backbone amide), and CH-pi (aromatic side-chain-aliphatic hydrogen) interactions. In the present work, the strength of the weakly polar interactions found in the TC5b miniprotein was quantified using all of the available 38 NMR structures (1L2Y) from the Protein Data Bank with DFT quantum chemical calculations at the BHandHLYP/cc-pVTZ level of theory and molecular fragmentation with capping of the partial structures. The energies of interaction between the individual residues of the Trp-cage range between -5.85+/-1.41 and -21.30+/-0.88 kcal mol(-1), leading to a significant total structural stabilization energy of -52.13+/-2.56 kcal mol(-1) of which about 50% is from the weakly polar interactions. Furthermore, the strengths of the individual weakly polar interactions are between -2.32+/-0.17 and -2.93+/-0.12 kcal mol(-1) for the CH-pi interactions, between -2.48+/-0.97 and -3.09+/-1.02 kcal mol(-1) for the Ar-NH interaction and -2.74+/-1.06 kcal mol(-1) for the Ar-Ar interaction.     

Conformational preferences of N-acetyl-L-leucine-N'-methylamide. Gas-phase and solution calculations on the model dipeptide

A DFT study of N-acetyl-l-leucine-N'-methylamide conformers in the gas phase and in solution was carried out. The theoretical computational analysis revealed 43 different conformations at the B3LYP/6-31G(d) level of theory in the gas phase. In addition, the effects of three solvents (water, acetonitrile, and chloroform) were included in the calculations using the isodensity polarizable continuum model (IPCM) and the Poisson-Boltzmann self-consistent reaction field (PB-SCRF) method. The stability order of the different conformers in solution has been analyzed. The theoretical results were compared with some experimental data (X-ray, IR, and NMR).     

State subsidy and moral hazard in corporate financing

This paper investigates the impact of state subsidy on the behavior of the entrepreneur under asymmetric information. Several authors formulated concerns about state intervention as it can aggravate moral hazard in corporate financing. In the seminal paper of Holmström and Tirole (Q J Econ 112(3):663–691, 1997) a two-player moral hazard model is presented with an entrepreneur initiating a risky scalable project and a private investor (e.g. bank or venture capitalist) providing outside financing. The novelty of our research is that this basic moral hazard model is extended to the case of positive externalities and to three players by introducing the state subsidizing the project. It is shown that in the optimum, state subsidy does not harm, but improves the incentives of the entrepreneur to make efforts for the success of the project; hence in effect state intervention reduces moral hazard. Consequently, state subsidy increases social welfare which is defined as the sum of private and public net benefits. Also, the exact form of the state subsidy (ex-ante/ex-post, conditional/unconditional, refundable/nonrefundable) is irrelevant in respect of the optimal size and the total welfare effect of the project. Moreover, in case of nonrefundable subsidies state does not crowd out private investors; but on the contrary, by providing additional capital it boosts private financing. These results are mainly due to the special mechanism imbedded in our model by which the private investor is able to transform even the badly designed state subsidies into a success fee which is optimal from the incentive point of view.     

The sodium diffusion in aluminium-oxide

The transport of Na through the polycrystalline ceramic arc tube of high intensity discharge lamps has been investigated. This complex process consists of several steps: solution in the ceramics, diffusion through the ceramics, leaving the bulk phase, evaporation from the surface. Among the listed processes the kinetics of the diffusion was examined in the temperature range 400-1200 °C, separately from other disturbing effects. X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectroscopy (SIMS) were used to determine the concentration depth profiles. The obtained results confirmed that the grain boundary diffusion plays an important role in the transport process of sodium through the ceramic wall. The bulk and the grain boundary diffusion coefficients and the temperature dependencies of these transport processes have been determined. The activation energy of Na bulk diffusion is 56.5 ± 6.7 kJ/mol at 900-1200 °C, respectively the activation energies of Na grain boundary diffusion amount to 97.5 ± 21.6 kJ/mol in the temperature range 700-1100 °C and 7.7 ± 4.0 × 10⁻² kJ/mol at 400-700 °C. The preexponential factor of the bulk diffusion was found to be D_o = 5.1 × 10⁻¹⁵ ± 9.5 × 10⁻¹⁷ cm²/s in the temperature range 900-1200°C, whereas the preexponential factors of grain boundary diffusion are D_o = 1.1 × 10⁻¹⁰ ± 1.1 × 10⁻¹¹ cm²/s at 700-1100 °C and D_o = 7.5 × 10^-15 ± 1.5 × 10⁻¹⁷ cm²/s at 400-700 °C.     

A three-body model for the study of resonance phenomena

A three-body model suitable for the investigation of compound, quasi-compound and potential resonances is presented. The exact solution of the model based on Faddeev's method is discussed. Numerical calculations are performed for negative total energy.     

Tensor force and Debye screening in quarkonium-type mesons

We use a non-relativistic quantum-mechanical model to investigate the effect of a screening plama on two quarkonium-type mesons: the charmonium and the bottonium. The stability of these mesons in the plasma is estimated in two cases: including the tensor and spin-orbit term in the potential and without these terms. It turns out that while the bottonium is somewhat stabilized by the tensor force, the charmonium becomes less stabil due to this modification of the potential. Thus the charmonium seems to be a more sensitive probe of the quark-gluon plasma formation than it was thought to be without including the tensor force.     

Nuclear spin-lattice relaxation of192Ir in ferromagnetic amorphous alloy Fe-B studied by nuclear orientation

The nuclear spin-lattice relaxation of¹⁹²Ir in the glassy alloy Ir_3.1Fe_80.5B_16.4 has been studied by low-temperature nuclear orientation technique. The thermal cycling method has been used. No dependence on extermal magnetic field in the range 0.25–1.2 T has been observed. Weger’s mechanism seems to play a crucial role.