Fourier transform infrared spectra and micelle formation of sodiumn-alkanesulfonates in aqueous solution

The concentration dependences of the Fourier transform infrared spectra of aqueous solutions of sodiumn-pentanesulfonate,n-hexanesulfonate,n-heptanesulfonate, andn-octanesulfonate were studied in concentration ranges encompassing the critical micellization concentrations (c.m.c). Changes in wavenumber, bandwidth, and intensity of infrared absorption bands were used to monitor the changes in molecular association with concentration. The premicellar aggregation below the c.m.c. may accompany the association of the alkyl chain, but not the counter-ion binding with the SO ₃ ^– group. Above the c.m.c, the front location of the counter-ion against the SO ₃ ^– group at the micelle surface is demonstrated.     

Infrared spectrum of HCN and HCN

The high-resolution spectrum of H¹²C¹⁴N has been measured near 4870 and 6060 cm⁻¹. The following bands have been identified and analyzed: 01¹2-00⁰0, 02⁰2-01¹0, 02²2-01¹0, 04⁰1-00⁰0, 11¹1-00⁰0, 12⁰1-01¹0, and 12²1-01¹0. The C---N stretching fundamental (ν₃) of H¹²C¹⁵N has also been measured near 2100 cm⁻¹. This fundamental is found to be 3 cm⁻¹ higher than previously reported. Other bands that have been identified in the H¹²C¹⁶N spectrum are 03¹0-00⁰0, 04⁰0-01¹0, 04²0-01¹0, and 01¹1-01¹0.     

Measurements of the D(sJ) resonance properties

We report measurements of the properties of the D(+)(sJ)(2317) and D(+)(sJ)(2457) resonances produced in continuum e(+)e(-) annihilation near sqrt[s]=10.6 GeV. The analysis is based on an 86.9 fb(-1) data sample collected with the Belle detector at KEKB. We determine the masses to be M(D(+)(sJ)(2317))=2317.2+/-0.5(stat)+/-0.9(syst) MeV/c(2) and M(D(+)(sJ)(2457))=2456.5+/-1.3(stat)+/-1.3(syst) MeV/c(2). We observe the radiative decay mode D(+)(sJ)(2457)-->D(+)(s)gamma and the dipion decay mode D(+)(sJ)(2457)-->D(+)(s)pi(+)pi(-) and determine their branching fractions. No corresponding decays are observed for the D(sJ)(2317) state. These results are consistent with the spin-parity assignments of 0(+) for the D(sJ)(2317) and 1(+) for the D(sJ)(2457).     

Observation of the radiative decay D0-->phigamma

We report the observation of the decay D0-->phigamma with a statistical significance of 5.4sigma in 78.1 fb(-1) of data collected by the Belle experiment at the KEKB e+e- collider. This is the first observation of a flavor-changing radiative decay of a charmed meson. The Cabibbo- and color-suppressed decays D0-->phipi(0), phieta are also observed for the first time. We measure branching fractions B(D0-->phigamma)=[2.60(+0.70)(-0.61)(stat)+0.15-0.17(syst)] x 10(-5), B(D0-->phipi(0))=[8.01+/-0.26(stat)+/-0.47(syst)] x 10(-4), and B(D0-->phieta)=[1.48+/-0.47(stat)+/-0.09(syst)] x 10(-4).     

Microscopic analysis of a thermal brownian motor

We study a genuine Brownian motor by hard disk molecular dynamics and calculate analytically its properties, including its drift speed and thermal conductivity, from microscopic theory.     

Vibrations of asymmetric rotors supported by asymmetric bearings

Summary In this paper the vibrations of an asymmetric flexible rotor supported by asymmetric bearings is theoretically analyzed by using Galerkin's method and the perturbation method, and numerically calculated. The effects of the asymmetries of the rotor and the bearings and the changes of the main instability regions and the ultraharmonic resonance due to the external and internal dampings are investigated. The experimental tests are performed on a smaller laboratory model in order to verify the validity of the theoretical results.The following results are obtained; the instability regions divide into two ones by the lack of the symmetries in the rotor and the bearings. The ultraharmonic resonances appear at fractional values of the main critical speed. The character of the internal damping is changed by the magnitude of the asymmetries of the rotor and the bearings.

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Übersicht Es werden die Schwingungen eines unsymmetrischen Rotors in unsymmetrischen Lagern analysiert. Dabei wird sowohl das Galerkin-Verfahren als auch eine Störungs-Methode angewendet. Untersucht werden die durch die Unsymmetrien von Rotor und Lagerung entstehenden Effekte sowie die durch äußere und innere Dämpfung entstehenden Änderungen der wichtigsten Instabilitätsbereiche und der ultraharmonischen Resonanzen. Zur Stützung der theoretischen Ergebnisse wurden Versuche an einem Laboratoriumsmodell durchgeführt.Die wichtigsten Ergebnisse sind folgende: Die Instabilitätsbereiche werden durch die Unsymmetrie von Rotor und Lagerung aufgespalten; ultraharmonische Resonanzen treten bei gebroochenen Werten der Hauptkritischen auf; der Charakter der inneren Dämpfung wird durch die Größe der Unsymmetrien von Rotor und Lagerung verändert.

     

Crystal Structures and Redox Responses Coupled with Ion Recognition of p‐Benzoquinone‐ and Hydroquinone‐Fused [18]crown‐6

The crystal structures and redox properties of p‐benzoquinone (BQ)‐fused [18]crown‐6 1 and bis‐BQ‐fused [18]crown‐6 2 were examined. The anion radicals of these BQ molecules were stabilized by addition of metal ions, through effective electrostatic interactions between the negatively charged BQ moiety and positively charged ion‐capturing [18]crown‐6 unit. The electrostatic interactions and solvation energy played important roles in determining the magnitudes of anodic redox shifts in the reduction potentials. Regular π‐stacking of BQ units and regular arrays of [18]crown‐6 units were observed in crystal 2 , in which one‐dimensional π‐electron columns were separated by ionic channels. The hydroquinone‐fused [18]crown‐6 molecule 3 and a new BQ‐ and phenol‐fused [18]crown‐6 derivative 4 were obtained as single crystals. The molecular conformations of [18]crown‐6 in crystal 3 and hydrated crystal 3 ?H₂O were different from each other.     

DNA Microenvironment Monitored by Controlling Redox Blinking

The rate of a bimolecular reaction between a fluorophore and a freely diffusing molecule in the solvent depends on the accessibility of the fluorophore for collision with the molecule. We previously reported that the observation of blinking, caused by the formation of R6G in the excited triplet state (³R6G*) and its quenching reaction with O₂, allowed us to monitor the DNA conformational changes between a duplex and a hairpin. However, the small molecular size of O₂ hampered sensitive monitoring of the microenvironment changes around R6G. In this study, we control redox blinking by adding a reductant ascorbic acid 2‐phosphate (VcP), which converts ³R6G* into the radical anion form R6G^.?, and by adding a bulky oxidant FeDTPA. The bimolecular electron‐transfer rate between R6G^.? and bulky FeDTPA was more strongly affected by microenvironment changes around R6G, compared with that between ³R6G* and the smaller O₂. This allowed us to monitor subtle DNA conformational changes caused by a single different nucleotide.     

Observation of direct CP violation in B0 --> pi+pi- decays and model-independent constraints on the quark-mixing angle phi2

We report a new measurement of the time-dependent CP-violating parameters in B(0)-->pi(+)pi(-) decays with 535 x 10(6) BB pairs collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider operating at the Upsilon(4S) resonance. We find 1464+/-65 B(0)-->pi(+)pi(-) events and measure the CP-violating parameters S(pipi)=-0.61+/-0.10(stat)+/-0.04(syst) and A(pipi)=+0.55+/-0.08(stat)+/-0.05(syst). We observe large direct CP violation with a significance greater than 5 standard deviations for any S(pipi) value. Using isospin relations, we measure the Cabibbo-Kobayashi-Maskawa quark-mixing matrix angle phi(2)=(97+/-11) degrees for the solution consistent with the standard model and exclude the range 11 degrees 相似文献   

Observation of the decay B(0)-->J/psieta

We report the first observation of B(0)-->J/psieta decay. These results are obtained from a data sample that contains 449 x10(6) BB[over] pairs accumulated at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We observe a signal with a significance of 8.1 sigma and obtain a branching fraction of (9.5+/-1.7(stat)+/-0.8(syst)) x 10(-6).