Persistent currents in a mesoscopic ring with a side connected quantum dot

We study the persistent current circulating along a mesoscopic ring with a dot side-coupled to it when threaded by a magnetic field. A cluster including the dot and its vicinity is diagonalized and embedded into the rest of the system. The result is numerically exact. We show that in the Kondo regime, the current can be a smooth or a strongly dependent function of the gate potential according to the structure of occupation of the highest energetic electrons of the system.     

Inherent peak compression of charged analytes in electrochromatography

This work resolves peak compression of charged analytes in CEC with strong cation‐exchange stationary phase particles. By combining electrochromatographic peak shape analysis with the results of numerical simulations and confocal laser scanning microscopy in the packed capillaries, we identify electrical field‐induced concentration polarization as the key physical phenomenon responsible for the inherent existence of local electrical field gradients on the scale of an individual support particle. Consequently, positive and negative field gradients exist between and inside the particles along the whole packing. Their intensity depends on the particles cation‐selectivity (governed by the particles volume charge density and the mobile phase ionic strength) and the applied field strength. The interplay of these local field gradients with the analytes retention (intraparticle adsorption) determines whether fronting, tailing, or spiked analyte peaks are observed, and it provides a mechanism by which strongly retained analytes can be eluted over long distances with little zone dispersion. Our analysis explains the “anomalous” peak compression effects with strong cation‐exchange particles, which have been reported more than a decade ago (Smith, N. W., Evans, M. B., Chromatographia 1995, 41, 197–203) and since then remained largely unresolved.     

The Limiting Behavior for Observations That Change with Time

Consider a system where units have random magnitude entering according to a homogeneous or nonhomogeneous Poisson process, while in the system, a unit's magnitude may change with time. In this paper, the authors obtain some results for the limiting behavior of the sum process of all unit magnitudes present in the system at time t.     

Strong Minimal Covers for Recursively Enumerable Degrees

We prove that there exists a nonzero recursively enumerable Turing degree possessing a strong minimal cover. Mathematics Subject Classification: 03D30.     

A survey of certain results on strong approximation by orthogonal series

This is a survey of results in a particular direction of the theory of strong approximation by orthogonal series, related mostly with author's contributions to the subject.     

On ejection of solar plasma enriched with 3He and Fe I at boundaries of coronal holes

The spectra and spectroheliograms in the He I λ = 1083.03 nm IR-line obtained with the horizontal solar telescope of the Sternberg State Astronomical Institute (SSAI) of Moscow State University are analyzed for the purpose of studying the increased solar activity at the boundaries of coronal holes. Our observations demonstrate plasma flux intensification at the boundary separating a coronal hole and a bipolar active region. In this case, the spectra in the vicinity of the He I λ = 1083.03 nm line point to a significant intensification in the lines of light isotope ³He I λ = 1083.168 nm and Fe I λ = 1082.837 nm. Acceleration of solar plasma fluxes at the coronal hole boundary in the immediate vicinity of an active region seems to be the result of reconnection of bipolar structure magnetic fields in the active region and a unipolar field of the coronal hole. The nature of ³He and Fe I particle enrichment in upward fluxes at the coronal hole boundaries is discussed. Original Russian Text ? L.M. Kozlova, B.V. Somov, 2009, published in Vestnik Moskovskogo Universiteta. Fizika, 2009, No. 3, pp. 94–98.     

Strong asymptotics for Krawtchouk polynomials

We determine the strong asymptotics for the class of Krawtchouk polynomials on the real line. We show how our strong asymptotics describes the limiting distribution of the zeros of the Krawtchouk polynomials.     

PURIFICATION OF L-METHIONINE AND N-ACETYL-D-METHIONINE FROM THE MIXTURE OF ENZYMATICALLY DEACYLATED N-ACETYL-DL-METHIONINE

N-acetyl-D-methionine, AaAc and the remams of N-acetyl-L-methionme dramatically.affect the purification of L-methionine when purified from the mixture of en.“ymatically deacylated N-acetyl-DL-methionine, leading to a low yield conventionally. Here, this paper reports a successful separation and purification of both L-methionine and N-acetyl-D-methionine by an H ion-exchange column. The pH, L-Met concentration and tile ratio between the content of sodium cation and the ion-exchange capacity were optimized to obtain the maximum yield. Experimental results indicate that, under the optimized conditions, the yields of L-methionine and N-acetyl-D-methionine can reach as high as 85% and 75%, respectively.     

On two types of discrete implications

This paper deals with two kinds of implications defined from t-norms, t-conorms and strong negations on a finite chain L: those defined through the expressions I(x, y) = S(N(x), T(x, y)) and I(x, y) = S(T(N(x), N(y)), y). They are called QL-implications and NQL-implications respectively. We mainly study those QL- and NQL-implications derived from smooth t-norms and smooth t-conorms. It is characterized when functions defined in these ways are implication functions, and their analytical expressions are given. It is proved that both kinds of implications agree. Some additional properties are studied like contrapositive symmetry, the exchange principle and others. In particular, it is proved that contrapositive symmetry holds if and only if S is the only Archimedean t-conorm on L, and T jointly with its N-dual t-conorm satisfy the Frank equation. Finally, some QL- and NQL-implications are also derived from non-smooth t-norms or non-smooth t-conorms and many examples are given showing that in this non-smooth case, QL- and NQL-implications remain strongly connected.