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Layered double hydroxide nanoparticles (LDHNPs) with exceptionally small particle sizes are synthesized using a tripodal ligand of tris(hydroxymethyl)aminomethane (THAM). For example, a LDHNP with the average size of 9.7 nm (denoted as LDH(10 nm), containing CO 3 2− in the interlayer), can be synthesized using a 2.0 M THAM solution. The 13 C CP/MAS NMR and FTIR analyses show that THAM is ligated to the layer as an alkoxide species. The average particle size of LDH synthesized using L-lysine (buffering base) instead of THAM is larger (47.9 nm) than that of LDH(10 nm). Therefore, the size reduction is possibly explained by the specific interaction of THAM with the layer via its multiple coordination. In addition, it is confirmed by the 13 C CP/MAS NMR analysis that LDH(10 nm) possesses CO 3 2− species weakly interacting with the layers. LDHNPs, in particular, as-synthesized LDH(10 nm) (denoted as LDH(10 nm)-as, containing CO 3 2− and Cl − in the interlayer), possesses the extremely high anion exchange abilities, and almost all anions in LDH(10 nm)-as are potentially exchangeable with NO 3 − , even under ambient (CO 2 -existing) conditions. Furthermore, LDH(10 nm)-as can act as an efficient reusable scavenger for harmful oxyanions and remove arsenic, selenium, and boron from their dilute aqueous solutions under ambient conditions.

In the presence of Mo6+-doped α-MnO2 (Mo–MnO2), various sulfides could efficiently be oxidized to the corresponding sulfoxides as the major products. In addition, Mo–MnO2 could repeatedly be reused.

As an alternative to correlation-based techniques widely used in conventional speckle metrology, we propose a new technique that makes use of phase singularities in the complex analytic signal of a speckle pattern as indicators of local speckle displacements. The complex analytic signal is generated by vortex filtering the speckle pattern. Experimental results are presented that demonstrate the validity and the performance of the proposed optical vortex metrology with nano-scale resolution.

Recently, atomic ensemble and single photons were successfully entangled by using collective enhancement [D. N. Matsukevich, et al., Phys. Rev. Lett. 95, 040405(2005).], where atomic internal states and photonic polarization states were correlated in nonlocal manner. Here we experimentally clarified that in an ensemble of atoms and a photon system, there also exists an entanglement concerned with spatial degrees of freedom. Generation of higher-dimensional entanglement between remote atomic ensemble and an application to condensed matter physics are also discussed.