A New Differential Lattice Boltzmann Equation and Its Application to Simulate Incompressible Flows on Non-Uniform Grids

A new differential lattice Boltzmann equation (LBE) is presented in this work, which is derived from the standard LBE by using Taylor series expansion only in spatial direction with truncation to the second-order derivatives. The obtained differential equation is not a wave-like equation. When a uniform grid is used, the new differential LBE can be exactly reduced to the standard LBE. The new differential LBE can be applied to solve irregular problems with the help of coordinate transformation. The present scheme inherits the merits of the standard LBE. The 2-D driven cavity flow is chosen as a test case to validate the present method. Favorable results are obtained and indicate that the present scheme has good prospects in practical applications.     

In vivo sodium-23 magnetic resonance surface coil imaging: Observing experimental cerebral ischemia in the rat

Sodium-23 magnetic resonance imaging can be used to detect and assess experimental cerebral ischemia in the rat. An imaging technique utilizing a surface coil is described to produce sodium magnetic resonance images of good quality and resolution within 10 min. A novel method of hemispheric occlusion showed edema in the right brain of the rat head within 3 hr after injury. The edema was especially pronounced by 12 hr with effects in the right brain, eye and surrounding muscle evident.     

Topological bootstrap theory of hadrons

A topological framework is constructed for anS-matrix bootstrap theory of particles. Each component of anS-matrix topological expansion is associated with a pair of intersecting “quantum” and “classical” surfaces whose complexity exhibits an entropy property. The bounded classical surface embeds graphs that carry the direct observables — energymomentum, spin and electric charge. The closed quantum surface carries a triangulation whose orientations represent internal quantum numbers — which turn out to be baryon number, lepton number and flavor. A form of “color” automatically appears. All strong-interaction components of the expansion are generated through “Landau connected sums” from “zeroentropy” surface pairs — which are self generating. Elementary particles correspond to triangulated areas on the quantum surface; consistency at zero entropy determines allowed hadrondisks on quantum spheres together with the associated quantum numbers. Elementary topological hadrons turn out to include mesons, baryons and baryoniums, with quarks appearing as “peripheral triangles” (along the perimenters of hadron disks) whose attachments correspond to a total of 8 flavors as well as spin. Individual quarks do not carry momentum and cannot be hadrons; quark confinement is automatic. Also appearing within hadron disks are “core triangles” that carry baryon number and electric charge but no flavor or spin. Hadron disks have quantum numbers that accord with the lowestmass physically-observed mesons and baryons. The relation of topological theory to QCD is discussed.     

Standpoint cosmology

An unorthodox cosmology is based on a notion of standpoint, distinguishing past from future, realized through Hilbert-space representation of the complex conformai group for 3+1spacetime and associated coherent states. Physical (approximate) symmetry attaches to eight-parameter complex Poincaré displacements, interpretable as growth of standpoint age (one parameter), boost of matter energy-momentum in standpoint rest frame (three parameters) and displacement of matter location in a compact U(1)O(4)/O(3) spacetime attached to standpoint (four parameters). An initial condition (at big bang) is characterized by a huge dimensionless parameter that breaks dilation invariance. Four major length scales are recognized, called Planck, particle, lab, and Hubble, with separations controlled by ; all physical concepts, including spacetime, depend on wideness of scale separation.     

X-ray imaging during plasma-source ion implantation

Plasma source ion implantation (PSII) is a technique for modifying stafaces that places the object to he modified directly into a plasma and then negatively pulse biases the object so as to implant positive ions. If the voltage is high enough, X-rays can he generated by electrons that are also accelerated by the pulse. This work describes techniques for imaging and characterizing the X-rays A pinhole camera was used to image the X-rays being emitted as electrons collided with surfaces in the chamber. The images show that X-rays are generated at the chamber walls and near the target. The time dependence of these X-rays during each pulse was examined using a PIN diode X-ray detector. Then, using another X-ray sensor and pulseheight analyzer, the spectra of the emitted X-rays was determined. The object is to relate the X-ray intensity and spectrum to the temporal and spatial values of the implantation dose so that it may he used as a process monitor and a control sensor.     

Hexagonal‐Shaped Tin Glycolate Particles: A Preliminary Study of Their Suitability as Li‐Ion Insertion Electrodes

Tin glycolate particles were prepared by a simple, one‐step, polyol‐mediated synthesis in air in which tin oxalate precursor was added to ethylene glycol and heated at reflux. Hexagonal‐shaped, micron‐sized tin glycolate particles were formed when the solution had cooled. A series of tin oxides was produced by calcination of the synthesized tin glycolate at 600–800 °C. It was revealed that the micron‐sized, hexagonal‐shaped tin glycolate now consisted of nanosized tin‐based particles (80–120 nm), encapsulated within a tin glycolate shell. XRD, TGA, and FT‐IR measurements were conducted to account for the three‐dimensional growth of the tin glycolate particles. When applied as an anode material for Li‐ion batteries, the synthesized tin glycolate particles showed good electrochemical reactivity in Li‐ion insertion/deinsertion, retaining a specific capacity of 416 mAh g^?1 beyond 50 cycles. This performance was significantly better than those of all the other tin oxides nanoparticles (<160 mAh g^?1) obtained after heat treatment in air. We strongly believe that the buffering of the volume expansion by the glycolate upon Li–Sn alloying is the main factor for the improved cycling of the electrode.     

Analysis of two-prong events in antiproton-proton interactions at 5.7 GeV/c

A study of elastic scattering, one-pion production and annihilation reactions in $\text{p}$p interactions at 5.7 GeV/c was carried out, from the two-prong events, obtained in the hydrogen bubble chamber exposed at CERN.Single particle distributions for the reactions $\text{pp}\text{→}\text{pp}\text{π}{}^0\text{,}\text{p}\text{p}\text{→}\text{p}\text{n}\text{π}{}^{\mathrm{+}}$ and $\text{p}\text{p}\text{→}\text{p}\text{n}\text{π}{}^{\mathrm{?}}$ are presented. The study of the squared momentum transfer distributions with and without charge exchange in the cross channel shows different behavior of the slope parameters versus the mass of the produced (Nπ) system. The cross sections for isobar production and for diffractive dissociation in the one-pion production reactions are obtained from a detailed Dalitz plot analysis. The results of the analysis of the decay angular distributions for the N(1510) and for the N(1680) produced in these reactions are in agreement with $\text{J =}\text{3}\text{2}\text{and}\text{J =}\text{5}\text{2}$ assignment, respectively. The cross sections of the annihilation reactions $\text{p}\text{p}\text{→ π}{}^{\mathrm{+}}\text{π}{}^{\mathrm{?}}\text{and}\text{p}\text{p}\text{→ π}{}^{\mathrm{+}}\text{π}{}^{\mathrm{?}}\text{π}{}^0$ are determined. Finally, we give some as aspects of the mass distributions for the last reaction.     

Intelligibility of vowels sung by a countertenor

Ten American English vowels were sung in a /b/-vowel-/d/ consonantal context by a professional countertenor in full voice (at F0 = 130, 165, 220, 260, and 330 Hz) and in head voice (at F0 = 220, 260, 330, 440, and 520 Hz). Four identification tests were prepared using the entire syllable or the center 200-ms portion of either the full-voice tokens or the head-voice tokens. Listeners attempted to identify each vowel by circling the appropriate word on their answer sheets. Errors were more frequent when the vowels were sung at higher F0. In addition, removal of the consonantal context markedly increased identification errors for both the head-voice and full-voice conditions. Back vowels were misidentified significantly more often than front vowels. For equal F0 values, listeners were significantly more accurate in identifying the head-voice stimuli. Acoustical analysis suggests that the difference of intelligibility between head and full voice may have been due to the head voice having more energy in the first harmonic than the full voice.     

Millimeter-wave imaging using FET detectors integrated with printed circuit antennas

The application of field effect transistor (FET) detectors integrated with planar twin dipole microstrip antennas to millimeter-wave imaging has been demonstrated. Circuits were configured as practical heterodyne mixers, as elements in a 2×3 element planar focal plane array for imaging, and as receivers in frequency modulated (FM) radars for three-dimensional imaging, at 63 GHz. These experiments show that quasioptical circuits, using conventional present-day FETs and simple printed circuit construction, can be applied usefully in the millimeter-wave region.