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1.
Experimental and numerical calculation results devoted to development of an optical system for an ion source based on a repetition rate CO2 laser are described. The laser chain consists of a master oscillator, gas absorber cells, and a four-pass amplifier. The optical system provides smooth laser pulses with variable duration and high spatial quality that ensures efficiency for plasma heating and ion generation. The parameters of the plasma ion component measured in the CERN laboratory are applied for a lead target illumination.  相似文献   
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Computer programs have been developed or are under development for the IBM personal computer that enable their users to get information on atomic charges, electrostatic potentials, conformational and other properties of molecular systems containing H, C, N, O, F, Si, P, S, or Cl atoms. The zero-order wavefunction is constructed of strictly localized molecular orbitals with fixed atomic orbital coefficients. The wave function can be refined by optimizing these coefficients, i.e., considering inductive effects via a coupled set of 2 × 2 secular equations within the CNDO /2 approximation. Delocalization and exchange effects are accounted for by expanding the wavefunction on a basis of the aforementioned strictly localized orbitals, instead of conventional atomic orbitals, and solving the corresponding SCF equations. Our method has been applied to the study of large systems. We calculated the electrostatic field of the complex of β-trypsin and basic pancreatic trypsin inhibitor and it has been found that strong field regions more or less coincide with hydration sites. A further potential application of protein electrostatic fields is in NMR spectroscopy. We found a linear correlation between CαH or backbone NH proton chemical shifts and the protein field at the site of the corresponding proton. At last, we propose a simple method to mimic the bulk around atomic clusters modeling crystalline and amorphous silicon. Based on this method we found a linear correlation between atomic net charges and bond angle distortions in silicon clusters with 35 atoms.  相似文献   
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The continuum part of the6Li (a,a)6Li (1.47–2.47 MeV) scattering data at Ea=50 MeV are extracted in two discretized bins. Coupled-channel calculations are carried out coupling the 1+ ground state of6Li with both the resonant, 3+ 1 state, and two non-resonant continuum states. The discretized continuum of the6Li (p,p)6Li (1.75–3.25 MeV) scattering data at Ep=65 MeV are also analysed on the same footing. In both the cases the effect of coupling is found to be minimal.  相似文献   
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Due to their inherent liability towards highly acidic conditions previously considered to be a prerequisite for data acquisition, betaxanthin structure dereplication by NMR spectroscopy has been scarcely reported and was, hitherto, exclusively based on 1H‐NMR data interpretation. Applying only slightly acidic conditions, we herein report the first 13C‐NMR data of two betaxanthins, i.e., indicaxanthin ( 1 ), isolated from yellow‐orange cactus pear fruits (Opuntia ficus‐indica [L.] Mill . cv. ‘Gialla’), and of miraxanthin V ( 2 ) from yellow Swiss chard petioles (Beta vulgaris L. ssp. cicla [L.] Alef . cv. ‘Bright Lights’), as derived by gHSQC‐ and gHMQC‐NMR experiments and inverse detection.  相似文献   
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The maximal sharpness of the forward peak in elastic scattering is constrained by unitarity. This is done by minimizing the average of |t|. The data are within 15% of the maximal sharpness. Our bound and an earlier lower bound on the forward slope constitute a severe restriction on the shape of forward peak.  相似文献   
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The set-up ‘energy plus transmutation’, consisting of a thick lead target and a natural uranium blanket, was irradiated by relativistic proton beams with the energy from 0.7 GeV up to 2 GeV. Neutron field was measured in different places of this set-up using different activation detectors. The possibilities of using the obtained data for benchmark studies are analyzed in this paper. Uncertainties of experimental data are shown and discussed. The experimental data are compared with results of simulation with MCNPX code.   相似文献   
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In thenatSn+20Ne (164,196 MeV) reactions gamma-ray spectra were observed in coincidence with fast alpha particles forward peaked and with those evaporated into a backward hemisphere. The observed differences in the form of the gamma-ray spectra and in the corresponding yields of high-energy gamma-rays are preliminary related to the time evolution of the deformation of the nuclear systems formed in the heavy ion induced fusion reaction.  相似文献   
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