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Abstract Adhesion is a technology for assembling carbon fiber (CF) reinforced polymer (CFRP), enabling them to maintain their lightweight and high-stiffness properties. Despite the importance of adhesion, the lack of a molecular-level understanding of the adhesion mechanisms has limited the reliability of adhesion for use in next-generation aircraft and automobiles. Here, we focused on the chemical-state distribution at a practical adhesive interface composed of an epoxy-based adhesive film bonded to an epoxy-based CF matrix. By fluorinating the OH group, we succeeded in visualizing the chemical state at the CF-matrix/adhesive interface using soft X-ray microscopy. The soft X-ray images exhibited a decrease in OH-related signals at the interface due to the local chemical interaction at the epoxy-epoxy adhesive interface. We also found that the N and O Kα signals were observable at the CF's surface, indicating the presence of nitrogen- and oxygen-containing functional groups. Based on these observations, we discuss the molecular-level adhesion mechanism at the CF-matrix/adhesive interface.

Understanding adhesion mechanisms for polymer composites is challenging due to the bonded interface being buried. Here, soft X-rays are used to probe the chemical and physical nature of the interface, revealing multiscale factors that influence the adhesion mechanism and bond strength.

We demonstrate high-throughput evaluation of the half-metallicity of Co2MnSi Heusler alloys by spin-integrated hard X-ray photoelectron spectroscopy (HAXPES) of composition-spread films performed with high-brilliance synchrotron radiation at NanoTerasu, which identifies the optimum composition showing the best half-metallicity. Co75–xMnxSi25 composition-spread thin films for x = 10–40% with a thickness of 30 nm are fabricated on MgO(100) substrates using combinatorial sputtering technique. The L21-ordering and (001)-oriented epitaxial growth of Co2MnSi are confirmed by X-ray diffraction for x = 18–40%. The valence band HAXPES spectra exhibit a systematic compositional dependence and the smallest photoemission intensity at the Fermi level (EF) for a slightly Mn-rich composition of x = 27%. The density of states (DOS) for L21-ordered Co2MnSi with different Mn compositions obtained from first-principles calculation also show the smallest total DOS at EF for x = 27% because of the formation of a clear half-metallic gap in the minority spin channel and the less localized d-states in the majority spin channel, indicating the best half-metallic nature of this composition. Our experimental results demonstrate that high-throughput evaluation of half-metallicity is possible even with spin-integrated HAXPES by capturing systematic changes in the electronic structures through the measurements on the composition-spread film. Moreover, the anisotropic magnetoresistance (AMR) of the composition-spread film is measured for electric current directions along the [110] and [100] of Co2MnSi. Previous studies indicated that a larger negative AMR ratio is a signature of a higher spin polarization. The largest negative AMR ratio is observed for x = 27% for both current directions, which also supports the best half-metallicity for this off-stoichiometric composition.

The electronic structure of the unoccupied and occupied states of potassium (K)-doped and undoped picene crystalline films has been investigated by using the element-selective and bulk-sensitive photon-detection methods of X-ray absorption and emission spectroscopies. We observed the formation of the doping-induced unoccupied and occupied electronic states in K-doped picene. By applying the inner-shell resonant-excitation experiments, we observed the evidence for the orbital hybridization between K and picene near the Fermi energy. Furthermore, the resonant X-ray emission experiment suggests the presence of the Raman-active vibronic interaction in K-doped picene. These experimental evidences play a crucial role in the superconductivity of K-doped picene.

The valence band structure of α-phase crystalline films of cobalt phthalocyanine (CoPc) grown on Au(111) is investigated by using angle-resolved photoemission spectroscopy (ARPES) with synchrotron radiation. The photo-induced change in the ARPES peaks is noticed in shape and energy of the highest occupied molecular orbital (HOMO, C 2p) and HOMO-1 (Co 3d) of CoPc, and is misleading the interpretation of the electronic properties of CoPc films. From the damage-free normal-emission ARPES measurement, the clear valence-band dispersion has been first observed, showing that orbital-specific behaviors are attributable to the interplay of the intermolecular ρ-ρ and ρ-d interactions. The HOMO band dispersion of 0.1 eV gives the lower limit of the hole mobility for α-CoPc of 28.9 cm² V-1 s-1 at 15 K. The non-dispersive character of the split HOMO-1 bands indicates that the localization of the spin state is a possible origin of the antiferromagnetism. [ABSTRACT FROM AUTHOR]

Let H be the quantum double of a Nichols algebra of diagonal type. We compute the R-matrix of 3-tuples of modules for general finite-dimensional highest weight modules over H. We also calculate a multiplicative formula for the universal R-matrix when H is finite dimensional. We show the unicity of a PBW basis (or a Lusztig-type Poincaré-Birkhoff-Witt basis) with a given convex order. [ABSTRACT FROM AUTHOR]

Analgesic tolerance to morphine can develop from long-term use of this drug for the treatment of pain. Many reports have shown that stimulation of the kappa opioid receptor (KOR) suppresses development of analgesic tolerance to morphine. Here, we studied the KOR-mediated inhibition of morphine tolerance during repeated morphine treatment, with a focus on desensitization of the receptor. The development of analgesic tolerance to morphine during repeated morphine administration (10 mg kg−1 s.c.) was completely suppressed by U-50488H (2 mg kg−1 i.p.), a KOR agonist. The decrease in [35S] GTPγS binding activity stimulated by the mu opioid receptor (MOR) agonist [D-Ala2, N-Me-Phe4, Gly5-ol]-enkephalin (DAMGO) was also significantly inhibited by U-50488H. These results indicate that stimulation of KOR caused by repeated morphine treatment either inhibits MOR desensitization or accelerates recycling of MOR on the cell surface, thereby suppressing morphine tolerance. Furthermore, we found that activity of protein kinase C (PKC) was significantly decreased in mice treated with both U-50488H and morphine. These results suggest that the mechanisms underlying KOR-mediated inhibition of analgesic tolerance to morphine may be partly due to suppression of PKC activation and prevention of receptor desensitization. [ABSTRACT FROM AUTHOR]

Abstract  The root systems appearing in the theory of Lie superalgebras and Nichols algebras admit a large symmetry extending properly the one coming from the Weyl group. Based on this observation we set up a general framework in which the symmetry object is a groupoid. We prove that in our context the groupoid is generated by simple reflections and Coxeter relations. In a broad sense this answers a question of Serganova. Our weak version of the exchange condition allows us to prove Matsumoto’s theorem. Therefore the word problem is solved for the groupoid. [ABSTRACT FROM AUTHOR]

A 1D metallic surface state was created on an anisotropic InSb(001) surface covered with Bi. Angle-resolved photoelectron spectroscopy (ARPES) showed a 1D Fermi contour with almost no 2D distortion. Close to the Fermi level (EF), the angle-integrated photoelectron spectra showed power-law scaling with the binding energy and temperature. The ARPES plot above EF, obtained thanks to a thermally broadened Fermi edge at room temperature, showed a 1D state with continuous metallic dispersion across EF and power-law intensity suppression around EF. These results strongly suggest a Tomonaga-Luttinger liquid on the Bi/InSb(001) surface. [ABSTRACT FROM AUTHOR]