Elastic Waves in Cylindrical Metal Wedges with Different Geometries

Acoustical Physics - The article presents results of numerical simulation and experimental studies of elastic wedge wave propagation in cylindrical wedges with positive and negative curvature in...     

基于反转光楔和泽尼克多项式的共形光学设计

采用一对反向旋转的累斯莱棱镜可以实现对目标视场的动态扫描,并应用一对内表面为泽尼克边缘矢高表面的透镜对共形光学整流罩引入的主要像差进行校正,剩余像差则由累斯莱棱镜内表面进行补充校正.设计实例中,通过比较光学系统校正前后的成像质量以验证这种校正方法的有效性.     

New Plasmon Waveguides Composed of Twin Metal Wedges with a Nano Gap

We have numerically shown the existence of coupled wedge plasmons (CWPs) which propagates along a nano gap of a twin metal wedge. The CWPs are formed by wedge plasmons which can interact with each other. The dispersion relations of the wavenumber, propagation distance, and beam area of CWPs, are described and show that the characteristics of CWPs are similar to those of wedge plasmons and of gap plasmons. We also propose a new plasmon waveguide composed of twin metal wedges with a nano gap.     

High-pressure gas lasers on Ar I,Xe I,and Kr I transitions

Lasing has been obtained in a high pressure (up to 17 atm) gas on Ar I, Xe I, and Kr I transitions. The gas was excited by a transverse discharge with volume preionization by a discharge through a dielectric. New laser lines belonging to Ar I (9123, 9658, 10470, and 11488 Å), Xe I (8232 Å), and Kr I (8929 Å) have been found. The dependences of the spectral and energetic characteristics of the He-Ar laser on the conditions of gas pressure and discharge have been investigated in detail. At high pressures, wide (about 50 HGz) laser lines have been found as well as high power (>10⁵ W) laser lines. Time characteristics of the radiation have been investigated and optimal conditions for the generation power have been defined.     

Collagen type I amide I band infrared spectroscopy

Collagen fiber structure and organization have been found to vary in different tendon types. Differences have been reported in the FT-IR spectra of the amide I band of collagen-containing structures. In the present study, the FT-IR spectral characteristics of the amide I band of the bovine flexor tendon and the extended rat tail tendon were compared by using the diamond attenuated total reflectance technique. The objective was to associate FT-IR spectral characteristics in tendons with their different collagen fiber supraorganization and biomechanical properties. Nylon 6 and poly-L-lysine were used as polyamide models. Each of these materials was found to exhibit molecular order and crystallinity, as revealed by their birefringence. The following FT-IR parameters were evaluated: amide I band profile, absorption peaks and areas, and the 1655 cm?1/1690 cm?1 absorbance ratio. The amide I area and the 1655 cm?1/1690 cm?1 absorbance ratio were significantly higher for the bovine flexor tendon, indicating that its collagen fibers are richer in pyridinoline-type cross-linking, proline and/or hydroxyproline and H-bonding, and that these fibers are more packed and supraorganizationally ordered than those in the rat tail tendon. This conclusion is additionally supported by differences in collagen solubility and biochemical/biomechanical properties of the tendons.     

I: METHODOLOGY

Since standard molecular simulations use different energy expressions for charge and gradient calculations, there are severe problems such as incompleteness in the optimization and simulation of the system with electrostatic (ES) interaction. Here, a new concept is proposed to solve this problem. The consistent charge equilibration (CQEq) equation has been derived which uses the same energy expression for both charge and gradient calculations. The ES energy is given by the atomic partial charge shielded with a nuclear charge described by a normalized S type Slater function located at each atomic site. The partial charge is determined by the variational principal for the ES energy with a constraint that the total sum of the partial charges is constant. Also the first derivative has been determined for the ES energy to the internal coordinates from the same ES energy expression. Although the CQEq is a little heavier than the original QEq for the charge calculation, the CQEq completely satisfies the variational principle for the ES energy of a set of partial charge, and satisfies the consistency requirement in the optimization of the system with ES interaction. A new code has been created and applied to test cases.     

Quantum leptogenesis I

Thermal leptogenesis explains the observed matter–antimatter asymmetry of the universe in terms of neutrino masses, consistent with neutrino oscillation experiments. We present a full quantum mechanical calculation of the generated lepton asymmetry based on Kadanoff–Baym equations. Origin of the asymmetry is the departure from equilibrium of the statistical propagator of the heavy Majorana neutrino, together with CP violating couplings. The lepton asymmetry is calculated directly in terms of Green’s functions without referring to “number densities”. Compared to Boltzmann and quantum Boltzmann equations, the crucial difference are memory effects, rapid oscillations much faster than the heavy neutrino equilibration time. These oscillations strongly suppress the generated lepton asymmetry, unless the standard model gauge interactions, which cause thermal damping, are properly taken into account. We find that these damping effects essentially compensate the enhancement due to quantum statistical factors, so that finally the conventional Boltzmann equations again provide rather accurate predictions for the lepton asymmetry.     

Logicoalgebraic structures I

In this survey article, some basic properties of quantum logics are described, such as physical motivation, basic examples and constructions, and state spaces and observables. Some recent results concerning joint distributions and commutators and their relations to uncertainty relations, Bell inequalities, independence of center, automorphisms and state space, are included.     

Stable potentials I

We discuss a conjecture of Ruelle concerningstable potentials on a group. For the groupsZ ₂,Z ₃, ₄, andZ ₆ any stable potential can be written as the sum of a non-negative function and a function of non-negative type. This is not true for the groupsZ _k (k odd, 5). For the Euclidean groupR ^v the question is open.Supported by NSF GP 7946.     

Photodissociation of the molecules SiCl3I and SiF3I

The parameters of lasing based on the transition of atomic iodine and occurring upon photodissociation of the molecules SiCl₃I and SiF₃I are experimentally investigated. The light source employed was a coaxial xenon-filled flash lamp of original construction. The main chemical reactions that accompany the photolysis of the molecules SiCl₃l and SiF₃I and determine the energy characteristics of the f~enerated radiation are analyzed.     

NAGNETIC FREEDERI CKSZ TRANSIT1 ONS OF NEMATi CS WITH NO'NIDEAL I N I T I A L ORIENTATIOFIS

MAGNETIC FREEDERICKSZ TRANSITIONS OF NEMATICS WITH NONIDEAL INITIAL ORIENTATIONS     

Relativistic oscillator strengths for some transitions in Cu(I), Ag(I) and Au(I)

Relativistic oscillator strengths have been calculated for transitions in the principal, sharp and diffuse series of Cu(I), Ag(I) and Au(I) spectra. The computations have been performed by employing a semiempirical method which includes exchange and core-polarization effects. A comparison is presented for the calculated ?_ik values with experimental and other theoretical data. The influence of core-polarization effects on oscillator strengths is discussed.