Study of N=20 shell gap with 1H(28Ne,27,28Ne) reactions

This paper reports on the ¹H(²⁸Ne,²⁸Ne) and ¹H(²⁸Ne,²⁷Ne) reactions studied at intermediate energy using a liquid hydrogen target. From the cross section populating the first 2⁺ excited state of ²⁸Ne, and using the previously determined B(E2) value, the neutron quadrupole transition matrix element has been calculated to be M_n=13.8 ±3.7 fm². In the neutron knock-out reaction, two low-lying excited states were populated in ²⁷Ne. Only one of them can be interpreted by the sd shell model while the additional state may intrude from the fp shell. These experimental observations are consistent with the presence of fp shell configurations at low excitation energy in ^27,28Ne nuclei caused by a vanishing N=20 shell gap at Z=10.     

Tl/Ge(1 0 0) system: Phase formation and phase transitions

Using scanning tunneling microscopy, phase formation and temperature-driven phase transitions in Tl/Ge(1 0 0) system have been studied. Evolution of Tl overlayer structure has been considered for three temperature ranges, including around room temperature (RT), high-temperature (HT) (350-450 K) and low-temperature (LT) (20-100 K) ranges. Upon RT growth, a 2 × 1-Tl phase develops in submonolayer range and is completed at around 1 ML of Tl. Cooling of the RT-deposited Tl overlayer results in formation of a set of various LT structures. These are 1D chains, 5 × 4-Tl and “stroked” phases observed in submonolayer range and a long-period c(12 × 14)-Tl phase developed at around 1 ML. All transitions between these RT and LT structures are reversible. At doses beyond 1 ML, RT deposition of Tl onto Ge(1 0 0) leads to the growth of second-layer Tl stripes, forming arrays with a 1 × 4 periodicity. Meanwhile, structure of the first layer also changes and it displays a set of various reconstructions, c(2 × 8), c(10 × 6) and c(10 × 7). All these structures remain unchanged upon cooling to LT. Growth at HT as well as heating of RT-deposited Tl overlayer irreversibly produces 3 × 2-Tl phase whose rows become decorated by second-layer Tl stripes at prolonged Tl deposition.     

Ultrafast optical switching from an ionic to a neutral state in tetrathiafulvalene-p-chloranil (TTF-CA) observed in femtosecond reflection spectroscopy

Ultrafast optical switching from an ionic ( I) to a neutral ( N) state in TTF-CA was observed in femtosecond reflection spectroscopy. Charge transfer excitation in the I phase produces N donor ( D0) acceptor ( A0) strings within 2 ps. These initial N states decay with a lifetime of 300 ps at 4 K, but rather multiply leading to macroscopic I-N conversion within 20 ps at 77 K just below the N-I transition temperature T(NI). Near T(NI), we also found the evidence for the coherent motion of the macroscopic N-I domain boundary with a period of 85 ps.     

Unified treatment of positron annihilation and positronium formation

The effects of the positron (e(+)) annihilation in e(+) scattering by the H atom are included directly in the Hamiltonian as an absorption potential, and hence the finite lifetimes Gamma(ns) of positronium (Ps) in states ns are automatically taken account of. The Schr?dinger equation is solved using the hyperspherical close-coupling method. The annihilation and Ps formation are shown to be inseparable near the Ps(1s) threshold E(th); Ps formation constitutes just an indirect pathway to annihilation. The annihilation cross section, which would diverge near E(th) if Gamma(1s) were infinite, connects smoothly across E(th) to the cross section for Ps formation, which is meaningful only at energies well above E(th).     

Characteristics of thin films formed by the ionized-cluster beam technique

The main characteristics of the metal films deposited by ionized-cluster beam deposition and their applications are described. These films showed good adhesion, high packing density, good conductivity, and unique diffusion characteristics of the deposited material onto Si substrates. These advantages have been utilized in fabricating electron devices such as flexible circuits, solar cells, and ohmic contacts.     

Physicochemical analyses of phase transition and dehydration processes of a new oral 1beta-methylcarbapenem antibiotic agent,CS-834

The characterizations of the anhydrate (A-form), monohydrate (B1-form), and dihydrate (B2-form) of CS-834 were investigated by powder X-ray diffraction, differential scanning calorimetry (DSC), thermogravimetry-differential thermal analysis (TG-DTA), infrared spectroscopy, and Karl Fischer moisture titration. The typical DSC curve of the B2-form showed five endothermic peaks at 35.0, 46.4, 56.2, 99.2, and 190.4 degrees C and an exothermic peak at 123.4 degrees C. In TG-DTA analysis, the three peaks at 35.0, 46.4, and 56.2 degrees C had a total weight loss of 7.3%, corresponding to the release of two water molecules. From morphological observation under thermomicroscopy, the endothermic peak at 99.2 degrees C was attributed to the melting of the dehydrous crystals (B0-form) and the exothermic peak at 123.4 degrees C to the recrystallization to the A-form crystals. The endothermic peak at 190.4 degrees C was due to the melting of the A-form crystals. After incubation for 6.0 h at 35, 50, 60, and 80 degrees C, the powder X-ray diffraction patterns of the B2-form indicated that it was converted into the A-form via the B1-form and B0-form. Thus CS-834 exists in homologous hydrous crystal forms in multiple-phase transformations with the dehydration of two water molecules.     

Facile Dehydrogenation of alpha-Amino Acids Chelated to a Ruthenium(II) Ion: (alpha-Imino acidato)ruthenium(II) Complexes

(alpha-Imino acidato)ruthenium(II) complexes, [Ru(II){N(R(1))=C(R(2))CO(2)}L(2)](+) (R(1) = R(2) = Me or R(1) = R(2) = -(CH(2))(3)-; L = 2,2'-bipyridine (=bpy) or 1,10-phenanthroline (=phen)), were obtained by anodic oxidation at a constant potential of the corresponding (alpha-amino acidato)ruthenium(II) complexes, N-methylalaninato or prolinato complexes, in good to excellent yields. (alpha-Imino acidato)ruthenium(II) complexes are stable in neutral or acidic aqueous solution. The half-wave potentials of alpha-imino acidato complexes are 0.73-0.78 V (vs SCE), which are more positive than those of the corresponding alpha-amino acidato complexes, 0.55-0.59 V. The crystal structure of [Ru(pro-H(2))(bpy)(2)]ClO(4).3H(2)O (pro-H(2) = 1,2-didehydroprolinato) has been determined by single-crystal X-ray analysis. Crystallographic data: space group C2/c, a = 21.73(1) ?, b = 19.33(1) ?, c = 14.58(1) ?, beta = 114.91(5) degrees, Z = 8, R = 0.0352. The length of the C=N double bond of the alpha-imino acidate moiety is 1.294(5) ?, and Ru-N(imino nitrogen) = 2.042(3) ?. The chelate ring of the alpha-imino acidato ligand is planar.     

Photoinduced DNA end capping via N3-methyl-5-cyanovinyl-2'-deoxyuridine

A modified oligodeoxynucleotide (ODN) containing N(3)-methyl-5-cyanovinyl-2'-deoxyuridine reacts by photoirradiation at 366 nm with an adenine residue of a complementary template ODN to yield an end-capped ODN in 87% yield.