Walks,walls, wetting,and melting

New results concerning the statistics of, in particular,p random walkers on a line whose paths do not cross are reported, extended, and interpreted. A general mechanism yielding phase transitions in one-dimensional or linear systems is recalled and applied to various wetting and melting phenomena in (d=2)-dimensional systems, including fluid films and p×1 commensurate adsorbed phases, in which interfaces and domain walls can be modelled by noncrossing walks. The heuristic concept of an effective force between a walk and a rigid wall, and hence between interfaces and walls and between interfaces, is expounded and applied to wetting in an external field, to the behavior of the two-point correlations of a two-dimensional Ising model belowT _c and in a field, and to the character of commensurate-incommensurate transitions ford=2 (recapturing recent results by various workers). Applications of random walk ideas to three-dimensional problems are illustrated in connection with melting in a lipid membrane model.Based on the Boltzmann Medalist address presented at the 15th IUPAP International Conference on Thermodynamics and Statistical Mechanics, Edinburgh, July 1983.     

Optical emission behaviors of C,Al, Ti,Fe, Cu,Mo, Ag,Ta, and W wire explosions in gaseous media

Electrical explosion of wires (EEW) is a promising method for nanopowders preparation and insensitive explosives ignition. Plasma radiation plays a key role in the ignition process while little attention has been paid on this phenomenon before. This letter introduces optical emission behaviors of electrical explosions for nine materials in air, Helium, and Argon with the SWE-2 platform. Experimental results indicated that the light intensity for non-refractory metals decayed rapidly after the discharge ended. In contrast, for refractory metals, the emission continued to increase and lasted for a long period after the discharge ceased. As for spectra, the emission consisted of line and continuous spectra. With the atomic number increased, the density of lines grew rapidly, leading to a “continuous” appearance.     

ICP-AES法测定金属硅中的Al、B、Ba、Ca、Cr、Cu、 Fe、Mg、Mn、Ni、Sr、Ti、V和Zn杂质元素

本文提供了一种测定金属硅中Ｂ,Ｆｅ,Ａｌ,Ｃａ,Ｍｎ等１４个杂质元素的ＩＣＰ－ＡＥＳ方法,在样品处理过程中,加入适量体积的甘露醇能够抑制Ｂ的挥发。用本方法测定了一个国家地球化学标准样（ＧＳＲ－４）,结果令人满意。     

Bits,time, carriers,and matter

The formal structure of quantum information theory is based on the well-founded concepts and postulates of quantum mechanics. In the present contribution, I am inverting the usual approach presented in textbooks by beginning with the use of bit states as basic and fundamental units of information and establish a dynamical map for them. The condition of reversibility, imposed on an ordered sequence of actions operating on a bit state, introduces, by necessity, the unitarity property of actions. I also verify that the uniformity of time, as a parameter for ordering events, is due to the admission of a composition law for the actions. In the limit of infinitesimal intervals between actions, a reversible and linear equation arises for the dynamical changes in time of a qubit (superposition of bit states). The admission that a bit of information is stored or carried by a massive particle necessarily leads to the Schrödinger–Pauli equation (SPE); the bit is associated to a spin 1/2. Within this approach, I verify that the particle dynamical equation becomes “enslaved” by the spin dynamics. In other words, the bit (or spin) precedes in status the particle dynamical evolution, being at the root of the quantum character of the standard Schr¨odinger equation, even when spin and spatial degrees of freedom are uncoupled.     

原子吸收光谱法测定中成药阿胶中铜、铬、镉、铅、砷、锑、锡和汞

本文以５０ｍｌ比色管作消化容器，硝酸－高氯酸混酸消化中成药阿胶，采用火焰原子吸收法测定其中的铜；石墨炉法测定其中的铬、镉、铅；氢化物法测定其中的砷、锑、锡。以硝酸－硫酸加过氧化氢水浴加热消化处理样品、采用冷原子法测定其中的汞，均取得较满意的结果。     

Quarks,diquarks, tetraquarks,and pentaquarks

A particle about 50% more massive than a proton, with positive charge, positive strangeness and positive baryon number, has been claimed in several experiments. Such a particle cannot be made from three quarks; its minimal configuration requires four quarks and an antiquark and it became known as a ‘pentaquark’. This article summarizes the evidence and concentrates on the theoretical interest that it has excited into the nature of correlations among quarks and antiquarks in the strong interaction limit of QCD.     

ICP—AES法测定铁矿中铝,钙,镁,锰,钴,铜,钠和钾

本文研究了ICP-AES法测定铁矿中铝,钙、镁、锰、钴、铜、钠和钾的方法。对仪器工作参数,共存元素的光谱干扰和基体效应干扰进行了探讨。采用向标准系列中加入铁基空白溶液建立工作曲线,试样经酸处理后即可直接测定。本方法获得了良好的回收率(95～103%)和变异系数(0.5～1.3%,n=11),同原子吸收法进行比对试验,结果一致。     

High-power,low-noise,Yb-doped,cladding-pumped,three-level fiber sources at 980 nm

We present results on a high-power, cladding-pumped, Yb-doped fiber emitting at 977 nm in laser and ampllified-spontaneous-emission source configurations. We obtained up to 1.4 W of fiber-coupled, single-mode output power and slope efficiency as high as 68%. To our knowledge these are the highest powers efficiencies achieved from a single-mode fiber laser at approximately 980 nm and the first demonstrated results on a high-power amplified-spontaneous-emission source in this wavelength range. High power and high slope efficiency are achieved by using a high numerical aperture (> 0.7), a jacketed air-clad fiber, and a high-brightness pump source. Both types of sources exhibit relative intensity noise below -130 dB/Hz and are thus suitable for a wide range of applications.     

Surface energies of the solid solutions between Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W

The surface energy for different surface orientations of the solid solutions as a function of concentration formed by Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W is computed and analyzed using the BFS method for alloys. Similarities and differences among the different binary alloys are examined in terms of strain and chemical effects.     

Density-functional calculations of alpha, beta, gamma, delta, delta', and epsilon plutonium

Total energies for the six known polymorphs of plutonium metal have been calculated within spin and orbital polarized density-functional theory as a function of lattice constant. Theoretical equilibrium volumes and bulk moduli correspond well with experimental data and the calculated total energies are consistent with the known phase diagram of Pu. It is shown that a preference for the formation of magnetic moments, increasing through the alpha-->beta-->gamma phases, explains their position in the ambient pressure phase diagram and their anomalous variation of atomic density. A simple model is presented that establishes a relationship between atomic density, crystal symmetry, and magnetic moments which is universally valid for all Pu phases.     

Surmounting the Cartesian Cut Through Philosophy, Physics, Logic, Cybernetics, and Geometry: Self-reference, Torsion, the Klein Bottle, the Time Operator, Multivalued Logics and Quantum Mechanics

In this transdisciplinary article which stems from philosophical considerations (that depart from phenomenology??after Merleau-Ponty, Heidegger and Rosen??and Hegelian dialectics), we develop a conception based on topological (the Moebius surface and the Klein bottle) and geometrical considerations (based on torsion and non-orientability of manifolds), and multivalued logics which we develop into a unified world conception that surmounts the Cartesian cut and Aristotelian logic. The role of torsion appears in a self-referential construction of space and time, which will be further related to the commutator of the True and False operators of matrix logic, still with a quantum superposed state related to a Moebius surface, and as the physical field at the basis of Spencer-Brown??s primitive distinction in the protologic of the calculus of distinction. In this setting, paradox, self-reference, depth, time and space, higher-order non-dual logic, perception, spin and a time operator, the Klein bottle, hypernumbers due to Musès which include non-trivial square roots of ±1 and in particular non-trivial nilpotents, quantum field operators, the transformation of cognition to spin for two-state quantum systems, are found to be keenly interwoven in a world conception compatible with the philosophical approach taken for basis of this article. The Klein bottle is found not only to be the topological in-formation for self-reference and paradox whose logical counterpart in the calculus of indications are the paradoxical imaginary time waves, but also a classical-quantum transformer (Hadamard??s gate in quantum computation) which is indispensable to be able to obtain a complete multivalued logical system, and still to generate the matrix extension of classical connective Boolean logic. We further find that the multivalued logic that stems from considering the paradoxical equation in the calculus of distinctions, and in particular, the imaginary solutions to this equation, generates the matrix logic which supersedes the classical logic of connectives and which has for particular subtheories fuzzy and quantum logics. Thus, from a primitive distinction in the vacuum plane and the axioms of the calculus of distinction, we can derive by incorporating paradox, the world conception succinctly described above.     

Narrowband, tunable, frequency-doubled, erbium-doped fiber-amplifed transmitter

We report on the development of a fiber-based laser transmitter designed for active remote sensing spectroscopy. The transmitter uses a master oscillator power amplifier (MOPA) configuration with a distributed feedback diode-laser master oscillator and an erbium-doped fiber amplifier. The output from the MOPA is frequency-doubled with a periodically poled potassium titanium oxide phosphate crystal. With 35 W of single-frequency peak optical pump power, 8 W of frequency-doubled peak power was achieved. The utility of this single-frequency, wavelength tunable, power scalable laser was then demonstrated in a spectroscopic measurement of diatomic oxygen A band.     

Composite A,B,C,D-IRF-model invariants

In this work the introduction of generalized A,B,C,D interaction-round-a-face model invariants related to composite braid group representations will be proposed. The invariant polynomials are obtained in the framework of Witten's Chern-Simons theory summarizing recent works on link invariants. The primary intention is to present explicitly neglected results in the latter area and to outline in a pedagogical way the computation of a variety of known and new invariants. The close relationship of the topological interpretation of link invariants and the notion of generalized knot polynomials derived from integrable models in statistical mechanics is emphasized.     

Ab initio calculations of phonon spectra in ATiO3 perovskite crystals (A = Ca,Sr, Ba,Ra, Cd,Zn, Mg,Ge, Sn,Pb)

First-principles calculations of phonon spectra based on the density functional theory are carried out for calcium, strontium, barium, radium, cadmium, zinc, magnesium, germanium, tin, and lead titanates with a perovskite structure. By analyzing unstable modes in the phonon spectrum, the possible types of lattice distortion are determined and the energies of the corresponding phases are calculated. From analyzing the phonon spectra, force constants, and eigenvectors of TO phonons, a conclusion is drawn concerning the nature of ferroelectric phenomena in the crystals studied. It is shown that the main factors determining the possible appearance of off-center atoms in the A position are the geometric size and electronic configuration of these atoms.     

Very simple,carbuncle-free,boundary-layer-resolving,rotated-hybrid Riemann solvers

In this paper, we propose new Euler flux functions for use in a finite-volume Euler/Navier–Stokes code, which are very simple, carbuncle-free, yet have an excellent boundary-layer-resolving capability, by combining two different Riemann solvers into one based on a rotated Riemann solver approach. We show that very economical Euler flux functions can be devised by combining the Roe solver (a full-wave solver) and the Rusanov/HLL solver (a fewer-wave solver), based on a rotated Riemann solver approach: a fewer-wave solver automatically applied in the direction normal to shocks to suppress carbuncles and a full-wave solver applied, again automatically, across shear layers to avoid an excessive amount of dissipation. The resulting flux functions can be implemented in a very simple and economical manner, in the form of the Roe solver with modified wave speeds, so that converting an existing Roe flux code into the new fluxes is an extremely simple task. They require only 7–14% extra CPU time and no problem-dependent tuning parameters. These new rotated fluxes are not only robust for shock-capturing, but also accurate for resolving shear layers. This is demonstrated by an extensive series of numerical experiments with standard finite-volume Euler and Navier–Stokes codes, including various shock instability problems and also an unstructured grid case.     

Onsager,ice, biomembranes,dimer models and the F-model

Personal recollections give a sampling of some of Onsager's later interests in ice and biomembranes. The author's involvement in these topics led to modeling a particular biomembrane phase transition using dimer models. Recent work is described for a particularly rich dimer model which is isomorphic to the F-model in three kinds of fields (direct, staggered, and quarter). New results for the full three-dimensional phase diagram show (1) how the anomalous OK multicritical point is destroyed by a direct field, and (2) how a new line of critical points must be added to the phase diagram in direct and staggered fields obtained previously by Baxter, due to diverging susceptibilities in the quarter field.     

Positron annihilation studies in high-Tc superconductors RBa2Cu3Oy,R: La,Nd, Sm,Eu, Gd,Dy, Ho,Y, Er

Positron lifetime and Doppler broadening of the annihilation line measurements have been performed at room temperature in high-T_c superconductors RBa₂Cu₃O_y, where R: La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Er and 6.9 < y ≤ 7. Doppler broadening of the annihilation line measurements have also been performed in high-T_c superconducting samples R RBa₂Cu₃O_y, where R: Nd, Sm, Eu, Ho, Y, Er as a function of temperature between 14 K and 293 K. It was observed that the positron lifetime and the S parameter values at room temperature have no obvious trend in their variation from the yttrium substitution by a rare-earth element. It was also observed that the temperature dependence of the positron annihilation parameters is similar in the high-T_c superconducting samples.     

Gold,silver, and palladium nanoparticle/nano-agglomerate generation,collection, and characterization

Generation, collection, and characterization of gold, silver, and palladium nanoparticles and nano-agglomerates (collectively “nanoparticles”) have been explored. The nanoparticles were generated with a spark aerosol generator (Palas GFG-1000). They were collected using a deposition cell under diffusion and thermophoresis. The shapes and sizes of the deposited particles were measured using transmission electron microscopy (TEM). TEM images showed that the particles were in the range of 8–100 nm in diameter, and their shapes varied from nearly spherical to highly non-spherical. Thermophoresis enhanced the deposition of nanoparticles (over the diffusive or the isothermal deposition) in all cases. Further, the size distributions of the nanoparticles generated in the gas phase (aerosol) were measured using a scanning mobility particle sizer (SMPS 3080, TSI) spectrometer. The SMPS results show that an increase in the spark frequency of the generator shifted the size distributions of the nanoparticles to larger diameters, and the total particle mass production rate increased linearly with increase in the spark frequency. The computational fluid dynamics code Fluent (Ansys) was used to model the flow in the deposition cell, and the computed results conform to the observations.     

Elastic and brittle properties of the B2-MgRE (RE = Sc,Y, Ce,Pr, Nd,Gd, Tb,Dy, Ho,Er) intermetallics

The brittle and elastic properties of the B2-MgRE (RE = Sc, Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er) intermetallics have been investigated using first-principles density functional calculations. The calculated equilibrium lattice constants and enthalpies of formation are in overall agreement with the available experiment and theoretical results. The related physical properties of those compounds are compared with that of ductile YCu. The Fermi energy occurs above a peak in the DOS for B2-MgRE intermetallics, whereas for ductile YCu the Fermi energy occurs near a minimum in the DOS. For B2-YCu, the partial density of states of d-states at the Fermi energy is low, while for B2-MgRE the RE d-states are partially occupied, indicating their important roles in the directional bonding for this material. The Cauchy pressure (C₁₂-C₄₄) and the ratio of bulk to shear modulus B/G are used to assess the brittle/ductile behavior of B2-MgRE and YCu compounds. It can be concluded that the B2-MgRE alloys have brittle behavior. MgSc is the most brittle, and MgHo is the least brittle amongst those alloys.