No abstract

Tucson gem shows in February 2008, where it was sold by amber dealers and distributors under names such as "natural green Caribbean amber" or "very rare Baltic amber" (Pedersen, 2008). This material, which has a peridot-like bright greenish yellow to green color, displays a distinctive deeper green component than previously seen in amber, even in the rare green material from Mexico. Author AA visited Treasure Green Amber Ltd. in June 2007 and was provided with information on the material by general manager Hung Chi and sales manager Steven Wai. They stated that their "green amber" is obtained from natural amber-allegedly of Brazilian, Baltic, or other origin-that has been treated by a two-stage procedure involving long time intervals under controlled heat, pressure, and atmosphere, in an autoclave developed in Germany for heat treatment. The green color of the treated

No abstract

Supersonic He and Ar atomic beam scattering from C(60) and graphene monolayers adsorbed on a Pt(111) surface are demonstrated in order to obtain detailed insight into a gas-molecule collision that has not been studied in detail so far. The effective masses and phonon spectral densities of the monolayers seen by different projectiles are discussed based on classical models such as the hard cube model and the recently developed smooth surface model. Large effective masses are deduced for both the monolayers, suggesting collective effects of surface atoms in the single collision event. The effective Debye temperature of graphene was found to be similar to that reported in highly oriented pyrolytic graphite (HOPG), indicating that the graphene is decoupled well from the Pt substrate. A much smaller Debye-Waller factor was found for the C(60) layer, probably reflecting the strong C(60)-Pt(111) interaction.

Mononuclear phosphine sulfide Pd(0) complexes and a polymer-supported triphenylphosphine sulfide Pd(0) complex were prepared as new air-stable Pd(0) catalysts for C-C coupling reactions. The phosphine sulfide Pd(0) complexes are not decomposed after completion of Suzuki-Miyaura coupling, and the polymer-supported Pd(0) catalyst is practically recyclable, while phosphine Pd(0) complexes are decomposed into inactive Pd(0) black after consuming the substrates. New catalytic activity of Pd(0) that promotes chalcogen atom replacement of phosphine chalcogenides (R 3 PdX, X = O, S, Se) is reported. A mechanistic study revealed that the new catalytic chalcogen replacement results from activation of the PdX bond as well as promotion of the oxidative chalcogenide formation. The intermediate phosphine was successfully trapped as a phosphine Pd(II) complex, and the PdX bond activation is applicable to regeneration of phosphine or phosphine sulfide from oxidized phosphine.

The reaction of 2-(α,β-unsaturated)acyl-3-phenyl-l-menthopyrazoles (9) with dienes gave Diels−Alder adducts in good yield. The addition of MgBr2·OEt2 or ZnCl2 accelerated these reactions through the formation of chelating bonds such as N···Mg···OC or N···Zn···OC. The structural fixation by these catalysts also promoted the endo and diastereoselectivities of the Diels−Alder addition on the Re-face of the dienophiles. These results were supported by PM3 calculations, in which the heats of formation of the transition states anticipated the remarkable differences between the Re- and Si-facial attacks of the dienes.

No abstract

As robots progressively continue to enter human lives, it becomes important for robots to navigate safely and efficiently in crowded environments. In fact, efficient navigation in crowded areas is an important prerequisite for successful coexistence between humans and robots. In this paper, we explore an unconventional idea wherein a robot tries to achieve a more efficient navigation by influencing an obstructing human to move away by means of contact. First, preliminary human reaction experiments were conducted wherein we established that we can successfully induce a human to move in a desired direction. Following this result, we have proposed a novel motion planning approach which considers inducement by contact. The system is then verified through simulation and real experiments. The results show us that the proposed method can be utilized for safer and more efficient navigation in a crowded, but relatively static environment.All authors are with the Sugano Lab,