Laser modulation at the atomic level monthly report no. 8, 1 - 28 feb. 1965

Measurement of temperature dependence of energy levels involved in laser emissio

Laser modulation at the atomic level monthly report no. 7, 1-31 jan. 1965

Laser modulation at atomic level - yttrium- aluminum garnet emission and laser emission shift with homogeneous pulsed magnetic fiel

Research Notes : Inheritance of soybean electrophoretic variants

We have been using the technique of slab-gel electrophoresis (see Gorman and Kiang, 1977, 1978; Kiang, 1981; Kiang and Gorman, 1983, for methods) to study genetic diversity in G. max and G. soja. In last year\u27s Soybean Genet-ics Newsletter, we reported the accession-specific zymogram types (zymogram types are equivalent to phenotypes) observed in 253 named cultivars (maturi-ty groups 00-IV) for 15 enzyme systems (Gorman et al., 1982b). We have been studying the genetic basis for the differences between these zymogram types

Research Notes : Electrophoretic classification of the early maturity groups of named soybean cultivars

Over the last several years, our lab has been collecting electrophore-tic data for several enzyme systems in G. max and G. soja. While we have not yet completed analysis of all the available G. max or G. soja accessions, we have completed electrophoretic profiles for most of the named soybean cultivars in the early maturity groups (OOO-IV). We have been interested in using these electrophoretic profiles for cultivar identification, since a fairly complete identification can be made (Gorman and Kiang, 1977; and an article in preparation)

Size Effects in Carbon Nanotubes

The inter-shell spacing of multi-walled carbon nanotubes was determined by analyzing the high resolution transmission electron microscopy images of these nanotubes. For the nanotubes that were studied, the inter-shell spacing ${\hat{d}_{002}}$ is found to range from 0.34 to 0.39 nm, increasing with decreasing tube diameter. A model based on the results from real space image analysis is used to explain the variation in inter-shell spacings obtained from reciprocal space periodicity analysis. The increase in inter-shell spacing with decreased nanotube diameter is attributed to the high curvature, resulting in an increased repulsive force, associated with the decreased diameter of the nanotube shells.Comment: 4 pages. RevTeX. 4 figure

Communications Biophysics

Contains reports on three research projects.United States Air Force (Contract AF19(602)-4112

Quasi one dimensional 4^4He inside carbon nanotubes

We report results of diffusion Monte Carlo calculations for both $^4$He absorbed in a narrow single walled carbon nanotube (R = 3.42 \AA) and strictly one dimensional $^4$He. Inside the tube, the binding energy of liquid $^4$He is approximately three times larger than on planar graphite. At low linear densities, $^4$He in a nanotube is an experimental realization of a one-dimensional quantum fluid. However, when the density increases the structural and energetic properties of both systems differ. At high density, a quasi-continuous liquid-solid phase transition is observed in both cases.Comment: 11 pages, 3ps figures, to appear in Phys. Rev. B (RC

Path-integral analysis of fluctuation theorems for general Langevin processes

We examine classical, transient fluctuation theorems within the unifying framework of Langevin dynamics. We explicitly distinguish between the effects of non-conservative forces that violate detailed balance, and non-autonomous dynamics arising from the variation of an external parameter. When both these sources of nonequilibrium behavior are present, there naturally arise two distinct fluctuation theorems.Comment: 24 pages, one figur

The three-dimensional Ising model: A paradigm of liquid-vapor coexistence in nuclear multifragmentation

Clusters in the three-dimensional Ising model rigorously obey reducibility and thermal scaling up to the critical temperature. The barriers extracted from Arrhenius plots depend on the cluster size as $B \propto A^{\sigma}$ where $\sigma$ is a critical exponent relating the cluster size to the cluster surface. All the Arrhenius plots collapse into a single Fisher-like scaling function indicating liquid-vapor-like phase coexistence and the univariant equilibrium between percolating clusters and finite clusters. The compelling similarity with nuclear multifragmentation is discussed.Comment: (4 pages, 4 figures

Inactivation of viruses by coherent excitations with a low power visible femtosecond laser

<p>Abstract</p> <p>Background</p> <p>Resonant microwave absorption has been proposed in the literature to excite the vibrational states of microorganisms in an attempt to destroy them. But it is extremely difficult to transfer microwave excitation energy to the vibrational energy of microorganisms due to severe absorption of water in this spectral range. We demonstrate for the first time that, by using a visible femtosecond laser, it is effective to inactivate viruses such as bacteriophage M13 through impulsive stimulated Raman scattering.</p> <p>Results and discussion</p> <p>By using a very low power (as low as 0.5 nj/pulse) visible femtosecond laser having a wavelength of 425 <it>nm </it>and a pulse width of 100 fs, we show that M13 phages were inactivated when the laser power density was greater than or equal to 50 <it>MW/cm</it>². The inactivation of M13 phages was determined by plaque counts and had been found to depend on the pulse width as well as power density of the excitation laser.</p> <p>Conclusion</p> <p>Our experimental findings lay down the foundation for an innovative new strategy of using a very low power visible femtosecond laser to selectively inactivate viruses and other microorganisms while leaving sensitive materials unharmed by manipulating and controlling with the femtosecond laser system.</p