A Systematic Investigation on Leaky Characteristics for NRD Guide with Arbitrary Profile of Cross-Section

The leaky characteristics of the NRD guide with arbitarary profile of cross section are systematically studied by a method which combines staircase approximation with multimode network theory and mode-matching procedure. Emphasis is laid on the investigation of the effect of the different profile dimensions on the leakage characteristics of the NRD guide. Extensive numerical results are given to establish useful guidelines for the design of some new types of NRD guide leaky wave antennas.     

Optical near-field distribution in an asymmetrically illuminated tip–sample system for laser/STM nanopatterning

In surface nano-patterning using an atomic force microscope (AFM) tip in scanning tunnelling microscopy (STM) mode and illuminated by a laser, two controversial physical mechanisms exist in the literature: the field-enhancement (FE) model and the thermal-induced mechanical contact (TMC) model. Due to the presence of evanescent waves in the optical near-field, the exact calculation of the field distribution of the tip–sample system in micro/nano scales becomes complicated. There is a lack of understanding of the asymmetrically illuminated tip–sample system. In this paper, full 3D finite-difference time-domain (FDTD) analysis was carried out to investigate the field distribution in different tip–sample systems. The effects of different tip/sample materials (either dielectric or plasmonic material), the gap distance, and laser incidence angles on the field distribution/enhancement have been studied. For the first time, we have demonstrated two new effects which are helpful in distinguishing the controversial mechanisms: (1) on the sample surface, the field peak position has a shift away from the tip-axis at large angles of incidence, and (2) the field enhancement could depend strongly on the horizontal component (perpendicular to tip-axis) of the incident wave instead of the vertical component (along tip-axis). The optimal incident angle is around 30° for the maximum field under the tip. The existence of field-distribution nodes on the 3D tip surface that leads to the in-homogenous heating of the tip is also predicted. PACS 81.16.Mk; 61.80.Ba; 81.16.Rf; 81.65.Cf     

Synthesis and properties of biphenyl-containing fluorenonophanes

A novel family of crownophanes containing 2,7-dioxyfluorenone and 4,4′-dioxybiphenyl fragments linked by tri- and tetraethylene glycol residues was obtained. The formation of pseudorotaxanes in reactions of these ligands with paraquat hexafluorophosphate was detected by FAB mass spectrometry, ¹H NMR spectroscopy, and electronic absorption spectroscopy.     

Semilocal smoothing spline of class <Emphasis Type="Italic">C</Emphasis><Superscript>1</Superscript>

The paper is aimed at the problem of restoring values of a function and its derivatives at intermediate points on the basis of given tabulated values. A special feature of the problem is that at a certain point, the tabulated values cease to be reliable and the process becomes stochastic. __________ Translated from Trudy Seminara imeni I. G. Petrovskogo, No. 26, pp. 347–367, 2007.     

On the solution of the trajectory survival problem for a nonlinear dynamical system

Nonlinear control systems possessing the flatness property are encountered in many applied mathematical models. In this paper, a trajectory survival problem is considered for a specific nonlinear system that possesses the above property. A method based on the properties of the system is proposed for constructing a control that solves the trajectory survival problem when the controlled object moves to the goal set within a bounding set containing an obstacle. Results of numerical calculations of the control and the trajectory of a system with a given initial position are presented.     

Edge diffraction of a Laguerre light beam

The phenomenon of transverse diffusion of ray amplitude along two principal orthogonal directions on the cylindrical surface of a diffracted boundary wave is observed in the diffraction of a Laguerre laser beam by the straight sharp edge of a planar safety-razor blade.     

Dielectric relaxation in polymers and copolymers of methacrylates and methacrylamides with chromophoric groups in side chains

The dielectric relaxation and molecular motion in polymers and copolymers of methacrylates and methacrylamides with π-conjugated anisodiametric chromophoric groups in the side chains are investigated in the temperature range from ?170 to 120–150°C at frequencies of 0.1–100 kHz. It is shown that the motion of chromophoric groups and relaxation transitions in these systems are similar to those in liquid-crystal polymers with side mesogenic chains. The chromophoric groups execute orientational motion of two types: orientational rotations about the long axes in the glass state and orientational rotations about the short axes at temperatures above T _g . The π-conjugation excludes local motion within the chromophoric group.     

Search for the lepton-number-violating decay Xi(-)-->pmu(-)mu(-)

A sensitive search for the lepton-number-violating decay Xi(-)-->pmu(-)mu(-) has been performed using a sample of approximately 10(9) Xi(-) hyperons produced in 800 GeV/c p-Cu collisions. We obtain B(Xi(-)-->pmu(-)mu(-))<4.0x10(-8) at 90% confidence, improving on the best previous limit by 4 orders of magnitude.     

Measurement of neutrino oscillation with KamLAND: evidence of spectral distortion

We present results of a study of neutrino oscillation based on a 766 ton/year exposure of KamLAND to reactor antineutrinos. We observe 258 nu (e) candidate events with energies above 3.4 MeV compared to 365.2+/-23.7 events expected in the absence of neutrino oscillation. Accounting for 17.8+/-7.3 expected background events, the statistical significance for reactor nu (e) disappearance is 99.998%. The observed energy spectrum disagrees with the expected spectral shape in the absence of neutrino oscillation at 99.6% significance and prefers the distortion expected from nu (e) oscillation effects. A two-neutrino oscillation analysis of the KamLAND data gives Deltam(2)=7.9(+0.6)(-0.5)x10(-5) eV(2). A global analysis of data from KamLAND and solar-neutrino experiments yields Deltam(2)=7.9(+0.6)(-0.5)x10(-5) eV(2) and tan((2)theta=0.40(+0.10)(-0.07), the most precise determination to date.