Van der Waals forces in density functional theory: perturbational long-range electron interaction corrections

Long-range exchange and correlation effects, responsible for the failure of currently used approximate density functionals in describing van der Waals forces, are taken into account explicitly after a separation of the electron-electron interaction in the Hamiltonian into short- and long-range components. We propose a "range-separated hybrid" functional based on a local density approximation for the short-range exchange-correlation energy, combined with a long-range exact exchange energy. Long-range correlation effects are added by a second-order perturbational treatment. The resulting scheme is general and is particularly well-adapted to describe van der Waals complexes, like rare gas dimers.Comment: 8 pages, 1 figure, submitted to Phys. Rev.

Summary of the recent short-haul systems studies

The results of several NASA sponsored high density short haul air transportation systems studies are reported as well as analyzed. Included are the total STOL systems analysis approach, a companion STOL composites study conducted in conjunction with STOL systems studies, a STOL economic assessment study, an evaluation of STOL aircraft with and without externally blown flaps, an alternative STOL systems for the San Francisco Bay Area, and the quiet, clean experimental engine studies. Assumptions and results of these studies are summarized, their differences, analyzed, and the results compared with those in-house analyses performed by the Systems Studies Division of the NASA-Ames Research Center. Pertinent conclusions are developed and the more significant technology needs for the evaluation of a viable short haul transportation system are identified

Absolute cross section for Si2+(3s21S→3s3p1P) electron-impact excitation

We have measured the absolute cross section for electron-impact excitation (EIE) of Si2+(3s21S→3s3p1P) from energies below threshold to 11 eV above. A beams modulation technique with inclined electron and ion beams was used. Radiation at 120.7 nm from the excited ions was detected using an absolutely calibrated optical system. The fractional population of the Si2+(3s3p3Po) metastable state in the incident ion beam was determined to be 0.210±0.018 (1.65σ). The data have been corrected for contributions to the signal from radiative decay following excitation from the metastable state to 3s3p1P and 3p23P, and excitation from the ground state to levels above the 3s3p1P level. The experimental 0.56±0.08-eV energy spread allowed us to resolve complex resonance structure throughout the studied energy range. At the reported ±14% total experimental uncertainty level (1.65σ), the measured structure and absolute scale of the cross section are in good agreement with 12-state close-coupling R-matrix calculations

Hemoperfusive Removal of Specific Intoxicants: The Role of the Rabbit in Preclinical Trials

Fjemelse af specifikke giftsloffer ved hemoperfusion Haemoperfusion er den foretrukne metode til direkte detoksifikation af patienter med akutte forgiftninger. Som adsorbant anvendes saedvanligvis kul. Den nyeste forskning indenfor dette omrade beskmftiger Sig med udvikling af specifikke adsorbanter til fjernelse at specitikke antistoffer, immunkomplekser 0g giftstoffer. Der gives en beskrivelse af en dyreeksperimentel model til udvikling af specifik detoksifikation ved anvendelse af haemoperfusion. Som forsagsdyr anvendes kaniner med permanente katetre i v. jugularis og a. carotis. Haemoperfusionssystemet bestfir af en peristaltisk pumpe og en stajle med agaroseperler (0.5—1.0 mm i diameter) indeholdende tusinder af mikrosphaerer (0.2 p. i diameter) koblet til specifikke antigener. Det arterielle blod pumpes fra a. carotis gennem sajlen til V. jugularis. Systemet perfunderes med hepariniseret saltvand (1 enh/ml) far brug, og kaninen hepariniseres med 300 enh heparin pr. kg legemsvaegt. Perfusionshastigheden er 8—15 ml/min, svarende til en perfusionshastighed p5. 20—30 min. I fig. 5 og 6 Vises resultaterne af forsog pa fjernelse af kviksolv og anti bovint serum albumin

Quantum Chaotic Scattering in Microwave Resonators

In a frequency range where a microwave resonator simulates a chaotic quantum billiard, we have measured moduli and phases of reflection and transmission amplitudes in the regimes of both isolated and of weakly overlapping resonances and for resonators with and without time-reversal invariance. Statistical measures for S-matrix fluctuations were determined from the data and compared with extant and/or newly derived theoretical results obtained from the random-matrix approach to quantum chaotic scattering. The latter contained a small number of fit parameters. The large data sets taken made it possible to test the theoretical expressions with unprecedented accuracy. The theory is confirmed by both, a goodness-of-fit-test and the agreement of predicted values for those statistical measures that were not used for the fits, with the data

Hemodynamic and ADH responses to central blood volume shifts in cardiac-denervated humans

Hemodynamic responses and antidiuretic hormone (ADH) were measured during body position changes designed to induce blood volume shifts in ten cardiac transplant recipients to assess the contribution of cardiac and vascular volume receptors in the control of ADH secretion. Each subject underwent 15 min of a control period in the seated posture, then assumed a lying posture for 30 min at 6 deg head down tilt (HDT) followed by 20 min of seated recovery. Venous blood samples and cardiac dimensions (echocardiography) were taken at 0 and 15 min before HDT, 5, 15, and 30 min of HDT, and 5, 15, and 30 min of seated recovery. Blood samples were analyzed for hematocrit, plasma osmolality, plasma renin activity (PRA), and ADH. Resting plasma volume (PV) was measured by Evans blue dye and percent changes in PV during posture changes were calculated from changes in hematocrit. Heart rate (HR) and blood pressure (BP) were recorded every 2 min. Results indicate that cardiac volume receptors are not the only mechanism for the control of ADH release during acute blood volume shifts in man

On the nonlinear dynamics of topological solitons in DNA

Dynamics of topological solitons describing open states in the DNA double helix are studied in the frameworks of the model which takes into account asymmetry of the helix. It is shown that three types of topological solitons can occur in the DNA double chain. Interaction between the solitons, their interactions with the chain inhomogeneities and stability of the solitons with respect to thermal oscillations are investigated.Comment: 16 pages, 16 figure

The Diffusion of the Magnetization Profile in the XX-model

By the $C^*$-algebraic method, we investigate the magnetization profile in the intermediate time of diffusion. We observe a transition from monotone profile to non-monotone profile. This transition is purely thermal.Comment: Accepted for publication in Phys. Rev.

Reevaluation of experiments and new theoretical calculations for electron-impact excitation of C3+

Experimental absolute-rate coefficients for electron-impact excitation of C3+ (2s2S1/2→2p2P1/2,3/2) near threshold [D. W. Savin, L. D. Gardner, D. B. Reisenfeld, A. R. Young, and J. L. Kohl, Phys. Rev. A 51, 2162 (1995)] have been reanalyzed to include a more accurate determination of optical efficiency and revised radiometric uncertainties which reduce the total systematic uncertainty of the results. Also, new R matrix with pseudostates (RMPS) calculations for this transition near threshold are presented. Comparison of the RMPS results to those of simpler close-coupling calculations indicates the importance of accounting for target continuum effects. The reanalyzed results of Savin et al. are in excellent agreement with the RMPS calculations; comparisons are also made to other measurements of this excitation. Agreement with the RMPS results is better for fluorescence technique measurements than for electron-energy-loss measurements