Kahlerian K3 surfaces and Niemeier lattices

Using results (especially see Remark 1.14.7) of our paper "Integral symmetric bilinear forms and some of their applications", 1979, we clarify relation between Kahlerian K3 surfaces and Niemeier lattices. We want to emphasise that all twenty four Niemeier lattices are important for K3 surfaces, not only the one which is related to the Mathieu group.Comment: Var7: 88 pages. We added last case

The rationality of the moduli spaces of Coble surfaces and of nodal Enriques surfaces

We prove the rationality of the coarse moduli spaces of Coble surfaces and of nodal Enriques surfaces over the field of complex numbers.Comment: 15 page

Investigation of twinning dynamics in VT1-0 titanium using acoustic emission

Use of acoustic emission signals makes it possible to analyze deformation processes in the bulk of a crystalline titanium structure formed under the effect of a concentrated strain created by loading of a diamond pyramidyesBelgorod State Universit

Twinning of alloy VT1-0 after total annealing

Twinning, that occurs in titanium VT1-0 crystals under the action of a concentrated stress, is studied by microindentation methods, recording of acoustic signals and probe microscopy. Some parameters and description of forms of a twinned interlayer in polycrystalline titanium VT1-0 are provided. The possibility of studying this process by recording acoustic emission signals is demonstratedyesBelgorod State Universit

Surface-enhanced optical third-harmonic generation in Ag island films

Surface-enhanced optical third-harmonic generation (THG) is observed in silver island films. The THG intensity from Ag nanoparticles is enhanced by more than two orders of magnitude with respect to the THG intensity from a smooth and homogeneous silver surface. This enhancement is attributed to local plasmon excitation and resonance of the local field at the third-harmonic wavelength. The diffuse and depolarized component of the enhanced THG is associated with the third-order hyper-Rayleigh scattering in a 2-D random array of silver nanoparticles.Comment: 4 pages, 2 figure

The Kodaira dimension of the moduli of K3 surfaces

The moduli space of polarised K3 surfaces of degree 2d is a quasi-projective variety of dimension 19. For general d very little has been known about the Kodaira dimension of these varieties. In this paper we present an almost complete solution to this problem. Our main result says that this moduli space is of general type for d>61 and for d=46,50,54,58,60.Comment: 47 page

Del Pezzo surfaces with 1/3(1,1) points

We classify del Pezzo surfaces with 1/3(1,1) points in 29 qG-deformation families grouped into six unprojection cascades (this overlaps with work of Fujita and Yasutake), we tabulate their biregular invariants, we give good model constructions for surfaces in all families as degeneracy loci in rep quotient varieties and we prove that precisely 26 families admit qG-degenerations to toric surfaces. This work is part of a program to study mirror symmetry for orbifold del Pezzo surfaces.Comment: 42 pages. v2: model construction added of last remaining surface, minor corrections, minor changes to presentation, references adde

Piezoelectric accelerator

Here we propose the conception of small-size piezoelectric accelerator of charged particles that operates due to the piezoelectric effect at varying mechanical force applied to piezoelectrics in vacuum. The accelerating voltage and the energy of accelerated particles are estimated. In the proof-of-principle experiment we demonstrate the effect of the emission of X-ray radiation at the mechanical compression of piezoelectric ceramics in vacuu

K3-fibered Calabi-Yau threefolds I, the twist map

A construction of Calabi-Yaus as quotients of products of lower-dimensional spaces in the context of weighted hypersurfaces is discussed, including desingularisation. The construction leads to Calabi-Yaus which have a fiber structure, in particular one case has K3 surfaces as fibers. These Calabi-Yaus are of some interest in connection with Type II -heterotic string dualities in dimension 4. A section at the end of the paper summarises this for the non-expert mathematician.Comment: 31 pages LaTeX, 11pt, 2 figures. To appear in International Journal of Mathematics. On the web at http://personal-homepages.mis.mpg.de/bhunt/preprints.html , #