Die Polymerisation von 1,3-Dioxolan mit einem Ionenaustauscher (Polystyrolsulfonsäure)

Ohne Zusammenfassung     

Superheavy hydrogen 5H and spectroscopy of 7He

Data on the spectroscopy of ⁵H and ⁷He from recent experiments with radioactive beams in Dubna and in RIKEN are presented.     

Mesoporous Zirconium Phenylenesiliconate‐phosphonate Hybrids with Ordered Lamellar Nanostructures

Novel ordered lamellar mesostructure pZrPS‐2 was hydrothermally prepared by using zirconium propoxide and 4‐(EtO)₂OPC₆H₄Si(OEt)₃ (pPPS‐E), which was hydrolyzed to organic building units substituted with both siliconate and phosphonate groups, in the presence of C_nTAB and TMAOH. The pZrPS‐2 materials were obtained at a Zr/PPS ratio of 2 or higher and the basal spacing was increased by using a longer‐chain surfactant (n=12–18). Removal of the occluded surfactants at 300 °C resulted in retention of the lamellar structure with negligible shrinkage of the interlayer distance. Nitrogen adsorption studies revealed the ordered mesoporous nature of pZrPS‐2 with a pore diameter of approximately 2 to 3 nm. The lamellar structure is assumed to be composed of layers that include zirconia‐based crystalline nanodomains and interlayer pillars mainly based on PPS units. Although lamellar structures with the same crystalline phase also formed when no surfactant was added or when the meta isomer of PPS was used, no mesoporous materials were obtained except pZrPS‐2. A possible schematic model to elucidate these results is also proposed.     

Moderate deviations of generalized method of moments and empirical likelihood estimators

This paper studies moderate deviation behaviors of the generalized method of moments and generalized empirical likelihood estimators for generalized estimating equations, where the number of equations can be larger than the number of unknown parameters. We consider two cases for the data generating probability measure: the model assumption and local contaminations or deviations from the model assumption. For both cases, we characterize the first-order terms of the moderate deviation error probabilities of these estimators. Our moderate deviation analysis complements the existing literature of the local asymptotic analysis and misspecification analysis for estimating equations, and is useful to evaluate power and robust properties of statistical tests for estimating equations which typically involve some estimators for nuisance parameters.     

Synthesis of 2,4-diiodoquinolines via the photochemical cyclization of o-alkynylaryl isocyanides with iodine

Upon photoirradiation of o-alkynylaryl isocyanides in the presence of iodine, the intramolecular cyclization of o-alkynylaryl isocyanides proceeds to afford the corresponding 2,4-diiodoquinolines in good yields. 2,4-Diiodoquinolines can be employed in transition metal-catalyzed cross-coupling reactions.     

Multicolor saccharide-sensing chips based on boronic acid-containing thin films showing stepwise release and binding of dyes

A novel saccharide sensor that shows a distinct color change resembling a "traffic signal" was developed. By copolymerizing a boronic acid monomer and an amine monomer on a glass plate, a boronic acid-containing thin film was obtained. After adsorbing anionic blue and yellow dyes, the thin film was immersed in aqueous saccharide solutions containing a cationic red dye. As saccharide concentration increased, the thin film changed its color from green to red via yellow. Origin of the distinct color change was attributed to a stepwise release and binding of dyes.     

Unified approach to catechin hetero-oligomers: first total synthesis of trimer EZ-EG-CA isolated from Ziziphus jujuba

A catechin hetero-trimer isolated from Ziziphus jujuba has been synthesized. Among three constituent monomers, (-)-epiafzelechin and (-)-epigallocatechin were prepared by de novo synthesis. Trimer formation relied on the unified approach to oligomers based on the bromo-capping and the orthogonal activation, reaching the reported structure of the natural product.     

Discovery of the First 2- State in 16C via Neutron Knockout Reaction

The ¹⁶C nucleus has been investigated by the neutron knockout reaction of ¹⁷C on a liquid hydrogen target. Applying the invariant mass method in inverse kinematics and γ-ray spectroscopy, the energy spectrum was reconstructed by triple-coincidence measurement, in which neutrons, charged fragments, and γ rays from the decay of the reaction residue (¹⁶C*) were detected. A peak at 0.47 MeV was observed in the invariant mass spectrum in coincidence with a peak at 0.74 MeV in the γ-ray spectrum, which indicates the presence of an unbound state with an excitation energy of 5.46 MeV. Comparison of the experimental cross section with the value derived by a theoretical calculation provided evidence that the spin-parity of this state is 2^?.     

Recoil proton tagged knockout reaction for He

We report for the first time the discrimination of the core fragment knockout and valence nucleon knockout reaction mechanisms at medium energy range, by the use of the recoil proton tagging technique. Intense ⁸He beams at 82.3 MeV/u were supplied by the RIPS beam line at RIKEN, and impinged on both hydrogen and carbon targets. Recoil protons were detected in coincidence with the forward moving core fragments and neutrons. The core fragment knockout mechanism is identified through the polar angle correlation and checked by various kinematics relations. This mechanism may be used to extract the cluster structure information of unstable nuclei. On the other hand, with the selection of the tagged valence nucleon knockout mechanism, a narrower peak of ⁷He ground state is obtained. The extracted neutron spectroscopic factor Sn=0.512(18) is relatively smaller than the no-tagged one, and is in good agreement with the prediction of ab initio Green?s function Monte Carlo calculations.