Adiabatic cooling of antiprotons

Adiabatic cooling is shown to be a simple and effective method to cool many charged particles in a trap to very low temperatures. Up to 3×10(6) p are cooled to 3.5 K-10(3) times more cold p and a 3 times lower p temperature than previously reported. A second cooling method cools p plasmas via the synchrotron radiation of embedded e(-) (with many fewer e(-) than p in preparation for adiabatic cooling. No p are lost during either process-a significant advantage for rare particles.     

Centrifugal separation of antiprotons and electrons

Centrifugal separation of antiprotons and electrons is observed, the first such demonstration with particles that cannot be laser cooled or optically imaged. The spatial separation takes place during the electron cooling of trapped antiprotons, the only method available to produce cryogenic antiprotons for precision tests of fundamental symmetries and for cold antihydrogen studies. The centrifugal separation suggests a new approach for isolating low energy antiprotons and for producing a controlled mixture of antiprotons and electrons.     

On the stability of an explicit difference scheme for hyperbolic equations with nonlocal boundary conditions

We consider the stability of an explicit finite-difference scheme for a linear hyperbolic equation with nonlocal integral boundary conditions. By studying the spectrum of the transition matrix of the explicit three-layer difference scheme, we obtain a sufficient condition for stability in a special norm.     

Magnetism of a cobalt-gold planar nanostructure on the silicon surface

The structural and magnetic properties of a cobalt nanolayer placed between a silicon substrate and a protective gold layer are studied. At a cobalt layer mass thickness of 1–2 nm, a nanoisland structure is shown to form. This thickness range is characterized by a local maximum of the magnetooptical Kerr effect and enhanced nonlinear optical and magnetic nonlinear optical responses at the second-harmonic frequency. This enhancement can be caused by the excitation of local surface plasmons and an increase in the local fields at the probing-radiation and second-harmonic frequencies in metallic nanoislands. The surface-sensitive nonlinear magnetooptical Kerr effect at the second-harmonic frequency is maximal at a cobalt layer thickness of about 2 nm, which corresponds to the characteristic scale of magnetization formation in the near-surface layer in cobalt.     

Integral representations of unbounded operators by infinitely smooth kernels

In this paper, we prove that every unbounded linear operator satisfying the Korotkov-Weidmann characterization is unitarily equivalent to an integral operator in L ₂(R), with a bounded and infinitely smooth Carleman kernel. The established unitary equivalence is implemented by explicitly definable unitary operators.     

A note on integral representations of linear operators

In this paper we describe families of those bounded linear operators that are simultaneously unitarily equivalent to integral operators with smooth Carleman kernels. The singleton case of the main result implies that every integral operator is unitarily equivalent to an integral operator having smooth Carleman kernel.     

Geometric Isomers of Cobalt(II) and Cobalt(III) Picolinates in Solution

Cobalt complexes with picolinic acid (HPic), namely, [Co^II(Pic)₂(H₂O)₂] · 2H₂O (I) and [Co^III(Pic)₃] · H₂O (II) are studied using ¹H and ¹³C NMR spectroscopy. Compound Iexists in solution as three geometric isomers, namely, trans-trans-trans, cis-trans-cis, and trans-cis-cis(molar ratio 4 : 2 : 1, respectively). According to ¹³C NMR data, compound IIexists in solution as a mer-isomer. The relative energy stability of the isomers was estimated using the molecular mechanics method.     

Synthesis and Structure of Co(III) Complexes with 2-Pyridinecarboxylic Acid

The Co(III) complexes with pyridinecarboxylic acid, Na[Co(Pc)₂(NO₂)₂] (I) and NH₄[Co(Pc)₂(NO₂)₂] (II), where Pc is the 2-pyridinecarboxylate anion, have been synthesized and studied by X-ray diffraction. In the crystal, the complex anions are combined through the Na⁺ and NH ₄ ⁺ cations. In II, the anion and the cation are combined by hydrogen bonds.     

Transport of a spherical transparent nanoparticle by radiation forces in the field of a Gaussian laser beam

The motion of a spherical transparent nanoparticle under the influence of radiation forces in the field of a Gaussian laser beam is investigated based on solution of Langevin equation. Expressions governing transverse and longitudinal velocities of the nanoparticle under the action of gradient and scattering forces are derived and analyzed. The possibility of spatial separation of nanoparticles having different sizes and optical properties is discussed.