Low-Energy Kaon�CNucleon/Nuclei Interaction Studies at DA��NE (SIDDHARTA and AMADEUS Experiments)

The DA??NE electron?Cpositron collider at the Laboratori Nazionali di Frascati of INFN has made available a unique quality low-energy negative kaons ??beam??. The SIDDHARTA experiment used this beam to perform unprecedented precision measurements on kaonic atoms, while the AMADEUS experiment plans to perform in the coming years precision measurements on kaon?Cnuclei interactions at low-energies, in particular to study the kaonic nuclei. The two experiments are briefly presented in this paper.     

Influence of Sb on a controlled-growth of aligned ZnO nanowires in nanoparticle-assisted pulsed-laser deposition

Single-crystalline ZnO nanowires on a sapphire substrate have been synthesized by a nanoparticle-assisted pulsed-laser deposition (NAPLD) using a pure and Sb₂O₃ doped ZnO target. Low density and vertically well-aligned ZnO nanowires were grown on hexagonal cone-shape ZnO cores by introduction of a ZnO buffer layer. More than 90% of the ZnO cores of the Sb-induced ZnO nanowires are formed in the same size of 400 nm. The ZnO nanowires consist of single-crystalline wurtzite ZnO crystal and grow along [0001] direction. The room-temperature photoluminescence spectrum exhibited a strong ultraviolet emission at around 380 nm and a relatively low broad band emission in the visible region, indicating a low concentration of structural defect in the nanowires. Sb can be used as one of the effective additives to control the morphology and alignment of ZnO nanowires synthesized by NAPLD.     

Investigation of debris dynamics from laser-produced tin plasma for EUV lithography light source

The dynamics of debris from the laser-produced tin (Sn) plasma was investigated for an extreme ultraviolet light source in order to establish the guideline for the optimum design of a mitigation system, such as a mass-limited target. The dissemination of the Sn atoms from the different shapes of a wire and a mass-limited droplet target were investigated using the laser-induced fluorescence (LIF) imaging method. The Sn droplet targets with a diameter in the range of 5 to 17 μm were prepared by a new droplet generating technique using a pulsed laser. There was a large difference in the angular distribution of Sn atoms in the plane parallel and perpendicular to the wire axis, indicating the curvature of the target surface governed the angular distribution of the ablated species. The spatial distributions of Sn atoms from the droplet targets were similar to those from the curved surface of the wire targets. The ablation dynamics of the droplet observed by a high-speed imaging camera is also discussed.     

One‐Pot Synthetic Procedure for2,2′‐Disubstituted Biaryls via the Suzuki Coupling Reaction of Aryl Triflates in a Biphasic Solvent System

A one‐pot synthetic procedure for 2,2′‐disubstituted biaryls was developed via a Suzuki cross‐coupling reaction of aryl triflates in a biphasic solvent system. The effects of various bases and solvents were investigated. Results showed that the Na₂CO₃–toluene/H₂O combination gave the highest yields.     

Laser spectroscopy of trapped 7Be and 10Be at a prototype slow RI-beam facility of RIKEN

A next-generation slow radioactive nuclear ion beam facility (SLOWRI) which provides slow, high-purity and small emittance ion beams of all elements is being build as one of the principal facilities at the RIKEN RI-beam factory (RIBF). High energy radioactive ion beams from the projectile fragment separator BigRIPS are thermalized in a large gas catcher cell. The thermalized ions in the gas cell are guided and extracted to a vacuum environment by a combination of dc electric fields and inhomogeneous rf fields (rf carpet ion guide). From there the slow ion beam is delivered via a mass separator and a switchyard to various devices: such as an ion trap, a collinear fast beam apparatus, and a multi-reflection time of flight mass spectrometer. In the R&D works at the present RIKEN facility, an overall efficiency of 5% for a 100A MeV ⁸Li ion beam from the present projectile fragment separator RIPS was achieved and the dependence of the efficiency on the ion beam intensity was investigated. Recently our first spectroscopy experiment at the prototype SLOWI was performed on Be isotopes. Energetic ions of ¹⁰Be and ⁷Be from the RIPS were trapped and laser cooled in a linear rf trap and the specific mass shifts of these isotopes were measured for the first time.     

Adsorption properties of activated carbon from waste newspaper prepared by chemical and physical activation

Adsorption properties of activated carbons prepared from waste newspaper by chemical and physical activation were investigated using water vapor, ammonia, methane, and methylene blue (MB) as adsorbents. The water vapor adsorption isotherms show type V behavior and the maximum vapor adsorption of the chemically and physically activated products is about 1050 and 450 ml/g, respectively. The higher water vapor adsorption of the chemically activated products is attributed to the higher specific surface area (S(BET)) and greater hydrophilic activity (arising from the surface oxygen-containing functional groups) than in the physically activated products. The adsorption of ammonia and methane was measured by temperature-programmed desorption (TPD). NH(3) adsorption is found to be higher in the chemically activated product than in the physically activated product while methane adsorption is slightly higher in the physically activated products even though these have lower S(BET) values. In the MB adsorption, the chemically activated products show higher adsorption (390 mg/g) than the physically activated product. These results are suggested to be related to the surface characteristics.     

Making the liquid-phase catalytic hydrodechlorination of pce over Pd/C safer

Summary The hydrodechlorination of tetrachloroethylene in methanol (MeOH) over palladium catalysts on activated carbon (Pd/C) at 20°C and atmospheric pressure was rendered safer by using ethanol (EtOH), isopropanol (IPA) or water-alcohol mixtures as solvents. Adding water to MeOH was better than using EtOH or IPA since it resulted in a faster reaction and better stability of Pd/C, which could also be completely reactivated.     

Mechanochromism,Twisted/Folded Structure Determination,and Derivatization of (N‐Phenylfluorenylidene)acridane

(N‐Phenylfluorenylidene)acridane (Ph‐FA) compounds with electron‐withdrawing and ‐donating substituents (H, MeO, Ph, NO₂, Br, F) at the para position of the phenyl group were successfully synthesized by Barton–Kellogg reactions of N‐aryl thioacridones and diazofluorene. By using the substituent on the nitrogen atom to alter the electronic properties, both the folded and twisted conformers of p‐NO₂‐C₆H₄‐FA could be crystallographically characterized, which enabled the charge transfer from the electron‐donating acridane moiety to the electron‐accepting fluorenylidene moiety to be understood. Ground‐state mechanochromism, thermochromism, vapochromism, and proton‐induced chromism were demonstrated between the folded and twisted conformations of the conformers. Protonation and chemical oxidation of Ph‐FA gave two stable acridinium compounds, namely, the fluorenylacridinium and acridinium radical cations. The present study will contribute to the development of functional dyes and organic semiconductors.