No abstract

The organic extracts of two licorices, known in commerce as Russian and Xinjiang licorices, exhibited potent antimicrobial and antioxidant activity. The bioassay-directed chemical investigation of both licorices revealed glabrene, glabridin, and licochalcones A and B as active principles.

Multilayer adsorptions of xenon on the loosely packed form and the strongly compressed form of exfoliated graphite were investigated by pressure-volume and X-ray diffraction techniques. The adsorption isotherm of Xe at 107 K on the loosely packed substrate showed four layering transitions, as well as the hysteresis loop between adsorption and desorption branches. From the measurement of X-ray diffraction at each stage of the adsorption, it was found that bulk crystallites of Xe started to appear just after the formation of a bilayer even on the loosely packed formed, and some of them remained in coexistence with a monolayer in desorption. Thus, the hysteresis loop is directly associated with the capillary condensation of Xe within pores of this substrate. The adsorption isotherm of nitrogen at 77 K also showed hysteresis loop and confirmed the presence of the mesopores having widths of ca. 40 Á with the assumption of slitshaped pores in the loosely packed exfoliated graphite. The strong compression of the exfoliated graphite caused the formation of the pores with widths larger than ca. 80 Á.

No abstract

We study the level spacing distribution p(s) in the spectrum of random networks. According to our numerical results, the shape of p(s) in the Erdős-Rényi (E-R) random graph is determined by the average degree k and p(s) undergoes a dramatic change when k is varied around the critical point of the percolation transition, k = 1. When k 1, the p(s) is described by the statistics of the Gaussian orthogonal ensemble (GOE), one of the major statistical ensembles in Random Matrix Theory, whereas at k = 1 it follows the Poisson level spacing distribution. Closely above the critical point, p(s) can be described in terms of an intermediate distribution between Poisson and the GOE, the Brodydistribution. Furthermore, below the critical point p(s) can be given with the help of the regularized Gamma-function. Motivated by these results, we analyse the behaviour of p(s) in real networks such as the internet, a word association network and a protein-protein interaction network as well. When the giant component of these networks is destroyed in a node deletion process simulating the networks subjected to intentional attack, their level spacing distribution undergoes a similar transition to that of the E-R graph.

No abstract

Fabrication of aluminum oxide thin films by a lowpressure metalorganic chemical vapor deposition technique Appl.Stability of hydrogen in silicon nitride films deposited by lowpressure and plasma enhanced chemical vapor deposition techniques

We have proposed a new technique for high crystallinity polycrystalline SiGe thin films with homogeneous crystallinity. The key technologies, i.e., direct nuclei formation on the substrate surface and selective growth of the resulting nuclei to gains, were established irrespective of film composition in a reactive thermal CVD with GeF4 and Si2H6. High crystallinity poly-Si0.05Ge0.95 thin films could be obtained on SiO2 substrates at 375°C and poly-Si0.95Ge0.05 thin films at 450°C by simply tuning the growth pressure for selective growth of the nuclei after creating the nuclei on the substrates. We demonstrated that not only the crystallinity but also the electrical properties of the resulting films were improved very much compared with those of continuously grown films.