6,588 research outputs found
Nonlocality of nucleon interaction and an anomalous off shell behavior of the two-nucleon amplitudes
The problem of the ultraviolet divergences that arise in describing the
nucleon dynamics at low energies is considered. By using the example of an
exactly solvable model it is shown that after renormalization the interaction
generating nucleon dynamics is nonlocal in time. Effects of such nonlocality on
low-energy nucleon dynamics are investigated. It is shown that nonlocality in
time of nucleon-nucleon interactions gives rise to an anomalous off-shell
behavior of the two-nucleon amplitudes that have significant effects on the
dynamics of many-nucleon systems.Comment: 9 pages, 4 figures, ReVTeX
On the total mean curvature of non-rigid surfaces
Using Green's theorem we reduce the variation of the total mean curvature of
a smooth surface in the Euclidean 3-space to a line integral of a special
vector field and obtain the following well-known theorem as an immediate
consequence: the total mean curvature of a closed smooth surface in the
Euclidean 3-space is stationary under an infinitesimal flex.Comment: 4 page
Wave packet dynamics and valley filter in strained graphene
The time evolution of a wavepacket in strained graphene is studied within the
tight-binding model and continuum model. The effect of an external magnetic
field, as well as a strain-induced pseudo-magnetic field, on the wave packet
trajectories and zitterbewegung are analyzed. Combining the effects of strain
with those of an external magnetic field produces an effective magnetic field
which is large in one of the Dirac cones, but can be practically zero in the
other. We construct an efficient valley filter, where for a propagating
incoming wave packet consisting of momenta around the K and K' Dirac points,
the outgoing wave packet exhibits momenta in only one of these Dirac points,
while the components of the packet that belong to the other Dirac point are
reflected due to the Lorentz force. We also found that the zitterbewegung is
permanent in time in the presence of either external or strain-induced magnetic
fields, but when both the external and strain-induced magnetic fields are
present, the zitterbewegung is transient in one of the Dirac cones, whereas in
the other cone the wave packet exhibits permanent spatial oscillations.Comment: 13 pages, 10 figure
Generalized Neighbor-Interaction Models Induced by Nonlinear Lattices
It is shown that the tight-binding approximation of the nonlinear
Schr\"odinger equation with a periodic linear potential and periodic in space
nonlinearity coefficient gives rise to a number of nonlinear lattices with
complex, both linear and nonlinear, neighbor interactions. The obtained
lattices present non-standard possibilities, among which we mention a
quasi-linear regime, where the pulse dynamics obeys essentially the linear
Schr{\"o}dinger equation. We analyze the properties of such models both in
connection with their modulational stability, as well as in regard to the
existence and stability of their localized solitary wave solutions
On compression of Bruhat-Tits buildings
We obtain an analog of the compression of angles theorem in symmetric spaces
for Bruhat--Tits buildings of the type .
More precisely, consider a -adic linear space and the set of
all lattices in . The complex distance in is a complete system of
invariants of a pair of points of under the action of the complete
linear group. An element of a Nazarov semigroup is a lattice in the duplicated
linear space . We investigate behavior of the complex distance under
the action of the Nazarov semigroup on the set .Comment: 6 page
Studies of kinetics and thermodynamic parameters of cashmere dyeing with bio-preparation of Urtica Cannabina L,
In this study, dyeing Mongolian cashmere with bio-preparation extracted from Urtica cannabina L. was investigated. Dyeing experiments were carried out under varying pH, temperature and contact time. The results have been used to investigate the kinetic and thermodynamic parameters of dyeing cashmere. This process is pH dependent and it has been found that the most suitable condition is pH 4.5. Increase in adsorption capacity with increase in temperature indicates that the dyeing process is endothermic. Thermodynamic parameters like standard affinity (∆µ), standard enthalpy (∆H) and standard entropy (∆S) were evaluated
Reforestation of Brown Coal Dumps in Bashkortostan: Characteristics of the Soil and the Condition of Birch (Betula pendula Roth) Stands (Results of a 35-year Experiment)
In 1980–1984, reforestation of the dumps of the Kumertau brown coal deposit (Republic of Bashkortostan, Russia) was carried out. Birch stands were created on the dumps of overburdened rocks. The authors studied the agrochemical properties of soils, described the state of birch stands and established the patterns of metalaccumulation in birch organs 35 years after reforestation. It is established that 35 years after planting birch trees on the dumps, the trees are characterized as ‘healthy’. The concentration of copper, zinc, lead and cadmium in birch organs changes in the following sequence: root system > bark > shoots > leaves. Soil formation processes are noted in birch stands on dumps. The upper (0–20 cm) soil layer acidity shifted bytwo units to the acidic side. There is a slight decrease in the content of phosphorus and the exchange forms of calcium and magnesium. Thus, birch is a promising tree species for the reforestation of mining industry dumps.
Keywords: dumps, reforestation, Betula pendula Roth, metal accumulation, soil formation processe
DNA authentication technologies for product quality monitoring in the wine industry
Identification of wine product authenticity is a topical question in theRussian Federation. A solution to this problem can be DNA authentication of wines, which is a technological process of product authenticity control using genetic identification of the main plant ingredient — wine grape varieties. This type of wine verification is carried out by analyzing residual amounts of Vitis vinifera L. nucleic acids extracted from cell debris of final products by molecular genetic methods. The aim of this work is the analysis of the existing methods for extraction of nucleic acids from grapes, wine raw materials and commercial wines, as well as description of the molecular genetic approaches to technical genetic identification of grape varieties and authentication of wines made from them. The obtained data suggest suitability of DNA authentication of wine products as a supplement to earlier approved analytical methods (documentary, visual, sensory, physico-chemical)
- …