Synthesis and characterization of Ti–Ni shape memory alloy thin films by pulsed laser deposition

Shape-memory alloys are crucial in various industrial fields. However, a high-quality film synthesis method has not been established yet. Here we examine optimum conditions for synthesis of thin films by pulsed laser deposition of Ti–Ni alloy target in vacuum. We investigated surface morphologies and chemical compositions of the films which were obtained under various conditions. We found that the suitable Ti/Ni ratio was obtained by adjusting the distance between the target and the substrate in vacuum. In parallel, we analyzed plasma plume by optical emission spectroscopy and time-of-flight mass spectrometry. We discuss the basic behavior of ablated particles in vacuum.     

Selective Michael Reaction Controlled by Supersilyl Protecting Group

Selective Michael reaction of organolithium reagents to supersilyl methacrylate is reported. The method was able to control a single and double Michael addition. The successful termination of the process using the supersilyl protecting group allows for the controlled, chemoselective, and diastereoselective Michael reaction.     

A spectroscopic study of the D(0u+) ion-pair state of Br2 by the optical-optical double-resonance technique

An optical-optical double-resonance technique has been applied to study the D(0_u⁺) ion-pair state of Br₂ in a one-photon resonant three-photon absorption. The OODR transition proceeds through the high vibrational level of the B³Π(0_u⁺) state, which compromises a large Franck-Condon shift required for the excitation of Br₂ from the X¹Σ_g⁺ state to the D(0_u⁺) state. Dunham parameters of the D(0_u⁺) state, based on a global least-squares fit of 407 transitions (v′ = 0–16, J′ = 17–115), are Y₀₀ = 49928.443(41), Y₁₀ = 134.467(19), Y₂₀ = ?8.71(27) × 10^?2, Y₃₀ = ?3.36(10) × 10^?3, Y₀₁ = 4.2382(15) × 10^?2, Y₁₁ = ?1.061(36) × 10^?4, Y₂₁ = ?2.00(27) × 10^?6, and Y₀₂ = ?1.93(11) × 10^?8 for ⁷⁹Br₂ (all in cm^?1, and 3σ in parentheses). The single rovibronic fluorescence spectrum of the D(0_u⁺) state shows a transition terminating on the X¹Σ_g⁺ ground state, and establishes the absolute v′ numbering on the basis of the Franck-Condon factor calculations. The v′ = 2 and 3 levels of the D(0_u⁺) state are strongly perturbed due to the heterogeneous interaction with the 1_u state correlating with the same ionic products of the D(0_u⁺) state at the dissociation limit, $\text{Br}{}^{\mathrm{?}}\text{(}{}^1\text{S) +}\text{Br}{}^{\mathrm{+}}\text{(}{}^3\text{P}{}_2\text{)}$.     

Structure and stability of a homologous series of tin oxides

The structures and stabilities of a series of nonstoichiometric SnO2-x compounds, which are yet unknown experimentally, are predicted using the cluster expansion technique combined with first-principles calculations. A homologous series of Sn(n+1)O(2n) in which oxygen vacancies are layered on (101) planes of the rutile lattice is discovered. The homologous crystals are composed of divalent and quadrivalent Sn atoms. No trivalent Sn atoms are formed.     

Antineutrino science in KamLAND

The primary goal of KamLAND is a search for the oscillation of \({\bar{\nu }}_\mathrm{e}\) ’s emitted from distant power reactors. The long baseline, typically 180 km, enables KamLAND to address the oscillation solution of the “solar neutrino problem” with \({\bar{\nu }}_{e} \) ’s under laboratory conditions. KamLAND found fewer reactor \({\bar{\nu }}_{e} \) events than expected from standard assumptions about \(\overline{\nu }_e\) propagation at more than 9 \(\sigma \) confidence level (C.L.). The observed energy spectrum disagrees with the expected spectral shape at more than 5 \(\sigma \) C.L., and prefers the distortion from neutrino oscillation effects. A three-flavor oscillation analysis of the data from KamLAND and KamLAND + solar neutrino experiments with CPT invariance, yields \(\Delta m_{21}^2 \) = [ \(7.54_{-0.18}^{+0.19} \times \) 10 \(^{-5}\) eV \(^{2}\) , \(7.53_{-0.18}^{+0.19} \times \) 10 \(^{-5}\) eV \(^{2}\) ], tan \(^{2}\theta _{12}\) = [ \(0.481_{-0.080}^{+0.092} \) , \(0.437_{-0.026}^{+0.029} \) ], and sin \(^{2}\theta _{13}\) = [ \(0.010_{-0.034}^{+0.033} \) , \(0.023_{-0.015}^{+0.015} \) ]. All solutions to the solar neutrino problem except for the large mixing angle region are excluded. KamLAND also demonstrated almost two cycles of the periodic feature expected from neutrino oscillation effects. KamLAND performed the first experimental study of antineutrinos from the Earth’s interior so-called geoneutrinos (geo \({\bar{\nu }}_{e} \) ’s), and succeeded in detecting geo \({\bar{\nu }}_{e} \) ’s produced by the decays of \(^{238}\) U and \(^{232}\) Th within the Earth. Assuming a chondritic Th/U mass ratio, we obtain \(116_{-27}^{+28} {\bar{\nu }}_{e}\) events from \(^{238}\) U and \(^{232}\) Th, corresponding a geo \({\bar{\nu }}_{e}\) flux of \(3.4_{-0.8}^{+0.8}\times \) 10 \(^{6}\) cm \(^{-2}\)  s \(^{-1}\) at the KamLAND location. We evaluate various bulk silicate Earth composition models using the observed geo \({\bar{\nu }}_{e} \) rate.     

Growth of diameter-controlled carbon nanotubes from fe-v-o nanoparticles size-classified by ligand-exchanged fractional precipitation

Colloidal Fe-V-O nanoparticles prepared as carbon nanotube (CNT) growth catalysts were precisely size-classified by fractional precipitation. Furthermore, the classification ability was improved by the fractional precipitation after ligand exchange process, which allowed us to obtain narrower size distributions of nanoparticles. CNTs were grown from the nanoparticles in order to investigate the dependence of diameter distribution of CNTs on that of nanoparticles. The results show that the diameter distribution of CNTs grown from classified nanoparticles was narrower than that of CNTs grown from as-prepared nanoparticles.     

Alignment-retainable nitrogenation of cylindrical carbon nanotubes by thermal reaction with ammonia following UV oxidation: chemical alteration effects on electrical conductivity

Cylindrical carbon nanotubes (CNTs) pretreated by UV irradiation were able to react with NH(3) to give nitrogen-containing CNTs without destroying their vertically aligned morphology. This process provided incorporation of nitrogen mostly at pyridinic and pyrrolic sites and promoted disordering, which was correlated with decreased electrical conductivity of CNT yarns.     

Antineutrino science by KamLAND

KamLAND measured the $\bar{\nu }$_e’s flux from distant nuclear reactors, and found fewer events than expected from standard assumptions about $\bar{\nu }$_e propagation at the 99.998% confidence level (C.L.). The observed energy spectrum disagrees with the expected spectral shape at 99.6% C.L., and prefers the distortion from neutrino oscillation effects. A two-flavor oscillation analysis of the data from KamLAND and solar neutrino experiments with CPT invariance, yields Δm2=7.9−0.5+0.6×10−5 eV² and tan2θ=0.40−0.07+0.10. All solutions to the solar neutrino problem except for the large mixing angle (LMA) region are excluded. KamLAND succeeded in detecting geoneutrinos produced by the decays of ²³⁸U and ²³²Th within the Earth. The total observed number of 4.5 to 54.2, assuming a Th/U mass concentration ratio of 3.9 is consistent with 19 predicted by geophysical models. This detection allows better estimation of the abundances and distributions of radioactive elements in the Earth, and of the Earth’s overall heat budget.