Gamow-teller strengths of the inverse beta transition 176Yb-->176Lu for spectroscopy of proton-proton and other sub-MeV solar neutrinos

Discrete Gamow-Teller (GT) transitions 176Yb-->176Lu at low excitation energies have been measured via the ( 3He,t) reaction at 450 MeV and at 0 degrees. For 176Yb, two low-lying states are observed, setting low thresholds Q(nu) = 301 and 445 keV for neutrino ( nu) capture. Capture rates estimated from the measured GT strengths, the simple two-state excitation structure, and the low Q(nu) in Yb-Lu indicate that Yb-based nu detectors are well suited for a direct measurement of the sub-MeV solar electron-neutrino ( nu(e)) spectrum including pp neutrinos.     

Evaluation of the Mn Lα and Lβ Spectra of Mn Metal and of Various Mn-Oxides

The Mn Lα and Lβ spectra of Mn, MnO, Mn₃O₄, Mn₂O₃, and MnO₂ have been measured. Each Mn La spectrum has been deconvoluted into two bands, Lα_A and Lα_B, and the integrated Lα_A/Lα_B intensity ratio was found to be inversely proportional to the Mn-0 inter-atomic distance, but proportional to the oxidation number. This finding tends to indicate the likelihood of crossover transition from oxygen to manganese. The intensity ratio Lβ/Lα_B of the pure metal was found to coincide closely with the statistically predicted value of 0.5. Furthermore, for Mn-metal, as well as for the oxides, the shift of the Lα_A band from the Lα_B band was found to agree with the change in the Lβ/Lα peak intensity ratio as a function of oxidation number.     

Phase transition of collagen and gelatin

Summary In order to investigate physical properties of semicrystalline high polymer, such as collagen or gelatin, over a wide temperature range, the phase change which might occur in this range is first of all required to elucidate. For this purpose, experiments seeking for the temperature dependence of linear thermal expansion, retractive stress, complex dynamic elasticity moduli, and equilibrium stress, the time rate of change of stress at constant temperatures, differential thermal analysis, and wide-angle X-ray diffraction analysis were performed on dried steer Achilles tendon fiber and gelatin film. The following conclusions were obtained. Tendon fiber consists of three regions of different structure: amorphous region having a second order phase transition point at 120 °C, less oriented unstable crystalline region having widely distributed melting temperatures over the range between 80–100° and 180 °C, and stable crystalline region having sharply distributed melting temperatures around 200 °C. Gelatin also consists of the same three regions, and the stable crystalline region is stabilized further by the higher degree of cross-linking having bonds of ionic nature and possesses its melting temperatures around 220 °C.

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Zusammenfassung Um physikalische Eigenschaften teilkristalliner Hochpolymerer wie Kollagen oder Gelatine zu untersuchen, wurde über einen weiten Temperaturbereich der Phasenwechsel, der in diesem Bereich eintritt, untersucht. Zu diesem Zweck wurde die Temperatur abh?ngigkeit der linearen thermischen Ausdehnung, die Zugkraft, der komplexe Elastizit?tsmodul, der Gleichgewichtszug, die Geschwindigkeit der ?nderung des Zugs bei konstanter Temperatur, ‘differential-thermoanalytische Daten und Weitwinkel-R?ntgenstreuung an getrockneter Stier-Achilles-Sehne und Gelatinefilm durchgeführt. Es ergaben sich folgende Schlüsse: Fasern der Sehnen bestehen aus drei Bereichen verschiedener Struktur: amorphen Bereichen, die einen Phasenübergang zweiter Ordnung bei 120 °C zeigen, weniger orientierten instabilen kristallinen Bereichen mit weit verteilten Schmelztemperaturen im Bereich zwischen 80–100 und 180 °C und stabilen kristallinen Bereichen mit scharf verteilten Schmelztemperaturen um 200° herum. Auch Gelatine besteht aus denselben drei Anteilen, und die stabilen kristallinen Bezirke sind au?erdem durch einen h?heren Grad von Vernetzung mit Bindungen ionischer Natur stabilisiert und besitzen Schmelztemperaturen um 220 °C.

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With 13 figures in 18 details and 1 table

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Dedicated to Prof. Dr. R. Hilsch for his 60th birthday.     

Trinucleon cluster structure at high-excitation energies in A=6 nuclei

Trinucleon molecular structures in ⁶He and ⁶Be were investigated by using the ⁶Li(⁷Li, ⁷Be)⁶He reaction at 455 MeV and ⁶Li(³He, t)⁶Be reaction at 450 MeV, respectively. Binary decays into t + t from a broad state at E _x =18.0±1.0 MeV in ⁶He and into ³He + ³He from one at E _x =18.0±1.2 MeV in ⁶Be, respectively, were observed by measuring trinucleon cluster decays in coincidence with reaction particles. The branching ratios for binary decay were estimated to be about 0.7 for ⁶He and ⁶Be. These large branching ratios show that a trinucleon cluster state exists as an isobaric partner around E _x =18 MeV in ⁶He and ⁶Be.     

'Non-covalent synthesis' of a chiral host of calix[6]arene and enantiomeric discrimination

'Non-covalent synthesis' of novel chiral hosts (calix[6]arene-chiral amine complexes) and its application to enantiomeric discrimination was investigated by (1)H NMR spectroscopy. The topology of a ternary complex was proposed for the calix[6]arene-amine-sulfoxide to rationalize the chiral recognition.     

Rheological properties of deionized Chinese ink

Rheological properties for Chinese ink in exhaustively deionized aqueous media were carefully examined. In the steady shear measurement, the shear viscosities of the ink could be well explained by considering the “effective” volume fraction of the particles in the ink including the electrical double layers and by using Einstein's equation for dilute suspension viscosity, when the particle volume fraction was substantially low. In the case that the volume fraction was higher, the shear viscosities showed extremely higher than those from Einstein's prediction, though the ink remained a Newtonian liquid. In the stress-strain measurement, the shear moduli were observed at strain smaller than 0.2. The “weak” aggregation among the particles in the ink under no shear or low shear rates was supported. It should be noted that the glue in the suspension plays an important role for the good liquidity of the ink and for the “weak” bridges among the particles resulting its good dispersion stability.     

Exciton dynamics within growth islands of GaAs/Al x Ga1−x As single quantum wells

Il Nuovo Cimento D - The localization dynamics of excitons within growth islands of GaAs/Al x Ga1−x As single quantum wells (SQW) have been investigated by time-resolved photoluminescence...     

Exceeding the classical capacity limit in a quantum optical channel

The amount of information transmissible through a communications channel is determined by the noise characteristics of the channel and by the quantities of available transmission resources. In classical information theory, the amount of transmissible information can be increased twice at most when the transmission resource is doubled for fixed noise characteristics. In quantum information theory, however, the amount of information transmitted can increase even more than twice. We present a proof-of-principle demonstration of this superadditivity of classical capacity of a quantum channel by using the ternary symmetric states of a single photon, and by event selection from a weak coherent light source. We also show how the superadditive coding gain, even in a small code length, can boost the communication performance of the conventional coding technique.     

A structure analysis of Ag-adsorbed Si(111) surface by LEED/CMTA

The Ag induced superstructures on the Si(111) surface have been studied by low energy electron diffraction constant momentum transfer averaging (LEED/CMTA) technique. The vertical displacements of the atoms are determined from the analysis of the specularly reflected (00) beam intensities. Unexpected behavior of the Ag atoms is clarified: For the √3 × √3-Ag surface it is verified that the Ag atoms are embedded in the first double layer of Si, leading to a considerable rearrangement of the substrate. In contrast, for the 3 × 1-Ag surface, the Ag atoms are riding on the Si surface and the reconstruction of the substrate is small.