Unipolar charging of nanoparticles by the Surface-discharge Microplasma Aerosol Charger (SMAC)

In this paper, we report the development of a novel unipolar charger for nanoparticles, a system that achieves low particle loss and high charging efficiency without the use of sheath air. The efficient unipolar charging of the system is realized mainly by the surface-discharge microplasma unit, a device previously applied with good success to the neutralization or charging of submicron particles [Kwon et al., 2005, Aerosol Sci. Technol., 39, 987–1001; 2006, J. Aerosol Sci., 37, 483–499]. The unipolar charger generates unipolar ions using the surface discharge of a single electrode with a DC pulse supply. This marks an advance from our previous method of generating bipolar ions with the use of dual electrodes in earlier studies. We evaluated the efficiency of the penetration (or loss) and charging of nanoparticles in the size range of 3–15 nm, then compared the charging efficiencies measured with those predicted by diffusion charging theory. More than 90% of inlet nanoparticles penetrated the charger (less than 10% of the particle were lost) without the use of sheath air. Other chargers have only realized this high penetration efficiency by relying on sheath air flow. Moreover, the measured charging efficiencies agreed well with those predicted by diffusion charging theory and were somewhat higher and more size-dependent than the charging efficiencies of other nanoparticle chargers.     

The first hetero-bifunctionalization of the secondary face of beta-cyclodextrin: selective and efficient conversion of the A-ring of a 2A,2B-disulfonate to 2A,3A-epoxymannoside

The A-ring of 2(A),2(B)-O,O-di(mesitylenesulfonyl)-beta-cyclodextrin was converted to 2(A),3(A)-epoxymannoside without affecting the other sulfonylated residue, which affords the first approach to hetero-bifunctionalization at the secondary hydroxyl side of cyclodextrins.     

Terabit all-optical logic based on ultrafast two-dimensional transmission gating

Terabit all-optical complementary logic is proposed using two successive time slots to represent a unique logical status. An organic molecular thin film is used as an array of optically controlled optical switches. By utilizing the planar structure of the film and its ultrafast optical response, proof-of-principle fully optical NOT and AND logic operations were demonstrated with 400-fs interval pulses.     

Kelvin-wave cascade on a vortex in superfluid 4He at a very low temperature

A study by computer simulation is reported of the behavior of a quantized vortex line at a very low temperature when there is continuous excitation of low-frequency Kelvin waves. There is no dissipation except by phonon radiation at a very high frequency. It is shown that nonlinear coupling leads to a net flow of energy to higher wave numbers and to the development of a simple spectrum of Kelvin waves that is insensitive to the strength and frequency of the exciting drive. The results are likely to be relevant to the decay of turbulence in superfluid 4He at very low temperatures.     

Photonic molecule lasing

Lasing at resonantly coupled whispering-gallery mode frequencies is observed in photonic molecules consisting of bispheres of 4.2 and 5.1 microm in diameter placed in a silicon V-groove. We examine spatial profiles of photonic molecule modes by use of frequency-resolved imaging and reveal bonding and antibonding mode features. From the lasing threshold characteristics, we quantitatively measure the quality factor and the spontaneous-emission coupling ratio of the photonic molecule modes and confirm that strong coherent coupling leads to photonic molecule modes.     

Highly stable gold(III) complex with a hydantoin ligand in alkaline media

A novel gold(III) complex with a monodentate 5,5-dimethylhydantoin ligand, [Au(dmh)4]-, is square planar in geometry, inert and highly stable in alkaline solutions because of soft acid-base interactions, and electrochemically reduced near -0.3 V vs Ag/AgCl to give a gold(0) film with a high current efficiency.     

Pd-catalyzed C3-selective allylation of indoles with allyl alcohols promoted by triethylborane

Under palladium catalysis, Et3B nicely promotes allyl alcohols to undergo C3-selective allylation of indoles and tryptophan; the yields range 75-95%.     

Generation of a chiral mesophase by achiral molecules: absolute chiral induction in the smectic C phase of 4-octyloxyphenyl 4-octyloxybenzoate

Achiral rodlike molecules possessing an ester group generated a chiral smectic liquid crystal phase.     

Lignan and neolignan derivatives from Magnolia denudata

A new tricyclo[4.2.0.0(2,8)]octane-type neolignan, 6-allyl-7-(3,4-dimethoxyphenyl)- 2,3-dimethoxy-8-methyl-tricyclo[4.2.0.0(2,8)]oct-3-en-5-one, together with 15 known lignan and neolignan derivatives have been isolated from the flower buds of Magnolia denudata DESR. and the structures of these compounds have been elucidated based on the 1H- and 13C-NMR spectra and two-dimensional NMR methods such as HMBC, HMQC, and NOESY.     

Giant optical activity in quasi-two-dimensional planar nanostructures

We examine the spectral dependence in the visible frequency range of the polarization rotation of two-dimensional gratings consisting of chiral gold nanostructures with subwavelength features. The gratings, which do not diffract, are shown to exhibit giant specific rotation (approximately 10(4) degrees/mm) of polarization in direct transmission at normal incidence. The rotation is the same for light incident on the front and back sides of the sample. Such reciprocity indicates three dimensionality of the structure arising from the asymmetry of light-plasmon coupling at the air-metal and substrate-metal interfaces. The structures thus enable polarization control with quasi-two-dimensional planar objects. However, in contradiction with recently suggested interpretation of experiments on larger scale but otherwise similar structures, the observed polarization phenomena violate neither reciprocity nor time-reversal symmetry.