Pionic atom factory project in the RIBF

We are preparing for a high resolution spectroscopy of the 1s and 2s pionic states of ¹²¹Sn in the ¹²²Sn(d,³He) reaction at the incident deuteron energy of ~500 MeV. The measurement will provide accurate information on the strong interaction between the pion and the nucleus, which leads to quantitative determination of the magnitude of the quark condensate at the normal nuclear density.     

Structure and properties for transparent polypropylene containing sorbitol‐based clarifier

Relation between structure and properties is studied for polypropylene (PP) containing 1,3:2,4‐di‐benzylidene sorbitol (DBS) that forms network structure composed of nanofibrils in a molten PP. It is found that the aggregation state of DBS, which can be controlled by the applied flow field and thermal history, affects the spherulite texture of PP and thus the transparency. When injection‐molded products, in which the nanofibrils of DBS orient to the flow direction, are reprocessed at 180 °C, that is, lower temperature than the melting point of DBS, the obtained material shows high level of transparency, although it has been believed that sorbitol‐derivatives have to be melted and dissolved into the molten PP at high temperature, for example, 240 °C. Further, it is found that the particle flow occurs in the blend at 180 °C. The applied shear force generates the particles, that is, flow units, by the fragmentation of the network structure. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 41–47, 2008     

Isolation of a bacterium from mangrove soil for degradation of sea sludge

Sea sludge, which is sediment of fish excrement and sewage on the sea bottom, continues to be a serious environmental problem. It has the potential to cause eutrophication and red tide, resulting in the death of shellfish and leading to an offensive odor. Soil taken from a mangrove swamp was added to sea sludge, which promoted an initial fermentation of the sludge components. This article reports on the isolation of a bacterium from mangrove soil that is involved in that fermentation. Three bacteria were isolated on a marine agar plate after incubating for 12 h at 60°C. One of these bacteria fermented sea sludge. 16S rDNA of this bacterium was sequenced, and it had a high homology with that of Bacillus fumarioli LMG17489^T (AJ250056).     

Auto‐Tandem Catalysis: A Single Catalyst Activating Mechanistically Distinct Reactions in a Single Reactor

Domino reactions have received great attention as efficient synthetic methodologies for the construction of structurally complex molecules from simple materials in a single operation. Catalysts in domino reactions have also been well studied. In these reactions, a catalyst activates the substrate(s) only once, and the structure of the product is delineated at that time. Recently, the new concept of “tandem catalysis” in domino reactions, in which catalyst(s) sequentially activate more than two mechanistically distinct reactions, has been proposed. Tandem catalysis is categorized into three subclasses: orthogonal‐, auto‐, and assisted‐tandem catalyses. Auto‐tandem catalysis is defined as a process in which one catalyst promotes more than two fundamentally different reactions in a single reactor. An overview of recent and significant achievements in auto‐tandem catalysis is presented in this paper.     

Photoisomerization dynamics study on cis-azobenzene derivative using ultraviolet-to-visible tunable femtosecond pulses

We performed the transient absorption measurement and the first rate equation (RE) analysis for cis isomer of 4-carboxy-2′,6′-dimethylazobenzene to clarify the quantitative difference between the photoisomerization process and the thermal relaxation process from the excited state. The RE analysis enabled us to determine the cis-to-trans photoisomerization rate per each pump pulse to be 3% under the condition of the 430 nm, 150 fs pump pulse with energy of 200 nJ. Moreover, the signal due to the yielded trans molecules appearing in the transient absorption was assigned from the following observed result: the transient absorbance change at the 380 nm probe mostly decreased within 300 fs after the 430 nm pulse pumping and then slowly decreased to zero, while the absorbance change at the 350 nm probe had a positive constant component in the over one picosecond time region. The RE analysis showed that this constant component is due to the yielded trans molecules, and its positive value is due to the fact that the absorption cross-section of the -to- transition in their trans molecules is larger than that of the -to- transition in the original cis molecules.     

Flame structure and stabilization of lean-premixed sprays in a counterflow with low-volatility fuel

An experimental study was performed on the combustion of lean-premixed spays in a counterflow. n-Decane was used as a liquid fuel with low volatility. The flame structure and stabilization were discussed based on the flame-spread mechanism of a droplet array with a low-volatility fuel. The spray flame consisted of a blue region and a yellow luminous region. The flame spread among droplets and group-flame formation through the droplet interaction were observed on the premixed spray side, while envelope flames were also observed on the opposing airflow side. The blue-flame region consisted of premixed flames propagating in the mixture layer around each droplet, the envelope diffusion flames around each droplet, the lower parts of the group diffusion flame surrounding each droplet cluster, and the envelope flame around droplets passing through the group flame. The flame was stabilized within a specific range of the mean droplet diameter via a balance between the droplet velocity and the flame-spread rate of the premixed spray.     

Ligand Effect on the Stability of Water-Soluble Iridium Catalysts for High-Pressure Hydrogen Gas Production by Dehydrogenation of Formic Acid

Aiming to develop a highly effective and durable catalyst for high-pressure H₂ production from dehydrogenation of formic acid (DFA), the ligand effect on the catalytic activity and stability of Cp*Ir (Cp*:pentamethylcyclopentadienyl anion) complexes were investigated using 5 different kinds of N,N’-bidentate ligands (bipyridine, biimidazoline, pyridyl-imidazoline, pyridyl-pyrazole and picolinamide). The Ir complex with biimidazoline ligand exhibited the highest catalytic activity, but deactivation occurred readily at high pressure. The pyridine moiety in the ligand can enhance the stability of Ir complex catalysts for the high-pressure reaction. The Ir complex catalyst containing pyridyl-imidazoline ligand showed the high activity and best stability under the high-pressure conditions.     

Structural Changes in Drawn Poly(L-lactide)/Clay Hybrid Films

The films composed of poly(L-lactide)(PLLA)/organoclay hybrids (PLACHs) have been prepared via a melt-compounding process, in which the organoclay paticles are uniformly dispersed in the PLLA matrix. The changes in PLLA crystal orientation for the uniaxially drawn films were studied by differential scanning calorimetry, X-ray diffractometry and transmission electron microscopy. Additionally, temperature dependence of the mechanical properties for these drawn films were examined by a dynamic viscoelastometer. After drawing the quenched PLACHs film at 90 °C, the orientation and crystallinity of PLLA crystal increased rapidly with increasing drawing ratio (λ) in the range more than 3 times. At the higher λ, the organoclay platelet particles in the PLACHs became parallel to the draw direction. The mechanical properties of drawn PLACHs were strongly dependent on both clay concentration and λ.     

Catalytic chemoselective addition of acetonitrile to enolizable aldehydes with cationic Ru complex/DBU combination

The cooperative catalysis of CpRu(PPh3)2(CH3CN)PF6 (1b) and DBU enables chemoselective nucleophilic activation of acetonitrile in the presence of base-sensitive aldehydes 2 to afford corresponding beta-hydroxynitriles in good yield.     

Direct synthesis of alkynyl(phenyl)iodonium salts from alk-1-ynes

Alkynyliodonium salts can be directly prepared from alk-1-ynes by the reaction with iodosobenzene, tetrafluoroboric acid, and a catalytic amount of HgO.