Correlation between energy levels of linear and bent X2Y2 molecules

The permutation-inversion group developed by Longuet-Higgins is extended to a classification of the vibronic, torsional, and rotational wavefunctions of a nonrigid X₂Y₂ molecule by introducing a symmetry operation $\text{T}\text{?}$, which rotates the top half of the molecule by 2π and, accordingly, the molecule-fixed x axis by π. Since the energy levels of linear (D_∞h) and bent (C_2h, C_2h, and C₂) forms of X₂Y₂ are classified according to a set of common symmetry operations of this extended permutation-inversion group, their energy levels can be correlated, including those of nonrigid forms such as a quasilinear system or a free internal rotor. Nuclear spin weights and selection rules are derived.     

Synthesis and properties of novel sulfonated (co)polyimides bearing sulfonated aromatic pendant groups for PEFC applications

Novel sulfonated diamines bearing aromatic pendant groups, namely, 3,5‐diamino‐3′‐sulfo‐4′‐(4‐sulfophenoxy) benzophenone (DASSPB) and 3,5‐diamino‐3′‐sulfo‐4′‐(2,4‐disulfophenoxy) benzophenone (DASDSPB), were successfully synthesized. Novel side‐chain‐type sulfonated (co)polyimides (SPIs) were synthesized from these two diamines, 1,4,5,8‐naphthalene tetracarboxylic dianhydride (NTDA) and nonsulfonated diamines such as 4,4′‐bis(3‐aminophenoxy) phenyl sulfone (BAPPS). Tough and transparent membranes of SPIs with ion exchange capacity of 1.5–2.9 meq g^?1 were prepared. They showed good solubility and high thermal stability up to 300 °C. They showed isotropic membrane swelling in water, which was different from the main‐chain‐type and sulfoalkoxy‐based side‐chain‐type SPIs. The relative humidity (RH) and temperature dependence of proton conductivity were examined. At low RH, the novel SPI membranes showed much higher conductivity than the sulfoalkoxy‐based SPIs. They showed comparable or even higher proton conductivity than Nafion 112 in water at 60 °C (>0.10 S cm^?1). The membrane of NTDA‐DASDSPB/BAPPS (1/1)‐s displayed reasonably high proton conductivities of 0.05 and 0.30 S cm^?1 at 50 and 100% RH, respectively, at 120 °C. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2862–2872, 2006     

Revisit to the intrinsic viscosity-molecular weight relationship of ionic polymers. 7. Examination of the Pals-Hermans dilution method with reference to the viscosity behavior of dilute aqueous dispersion of ionic polymer latex

The isoionic dilution method, which was proposed by Pals and Hermans, for linear ionic polymer solutions, was examined for the viscosity behavior of dilute aqueous dispersion of ionic latex [particle diameter, (0.120 ± 0.003) × 10^–6 m; surface charge density, 1.6 × 10^–6 C/cm²] in the presence of sodium chloride (5 × 10^–5 to 5 × 10^–4 M). Linear relations were obtained between the reduced viscosity and the latex concentration, when a parameter m, which appeared in the effective ionic strength introduced by Pals and Hermans, was chosen to be about 0.1. This finding on the latex system does not support that, at the salt and polymer concentrations employed, the dimension of linear macroions varies with changing effective ionic strength and it is kept constant along the isoionic dilution line. Brief discussion on the m value is presented. ©1995 John Wiley & Sons, Inc.     

Spinodal decomposition of Fe−Cr−Ni alloys studied by Mössbauer spectroscopy

Summary A thermodynamic calculation of the Fe−Cr−Ni phase diagram suggests that the composition 30 at.%Cr-5 at.%Ni is expected to be found inside the spinodal line, whereas 16 at.%Cr-5 at.%Ni is expected outside at 723 K. These two alloys have been thermally aged for time periods up to 40 minutes at 723K. A significant broadening of the magnetic-hyperfine-field distribution indicates that Fe-30 at.%Cr-5 at.%Ni undergoes typical spinodal decomposition in agreement with the calculation. Spinodal decomposition is distinguished from nucleation-growth by a detailed analysis of the magnetic-hyperfine-field distribution. Paper presented at ICAME-95, Rimini, 10–16 September 1995     

Large time behavior of bounded solutions to a parabolic system of chemotaxis in the whole space

We consider the Cauchy problem for a parabolic system of chemotaxis in RN(N?1), and give the decay rates and asymptotic profiles of bounded solutions.     

The Fourier transform and diode laser spectrum of the ν2 band of diazomethane

The infrared spectrum of the ν₂ band (NN stretching) of gaseous diazomethane at 2100 cm^?1 has been measured by means of an interferometer and a tunable diode laser spectrometer. For the first time the rotational J and K_a structure of this A-type parallel band has been resolved. Since the spectrum was found to be perturbed it was not possible to fit the upper state levels to an overall hamiltonian. Nine subbands have been analysed with the support of millimeter wave data for the ground vibrational state. Term values for the ν₂ = 1 vibrational state with K_a up to 5 have been obtained and subband origins, effective rotational constants B and centrifugal distortion constants D and H were determined for each K_a substate.     

The axisymmetrical response of a circular cylindrical double-shell system with internal damping

The axisymmetrical response of a circular cylindrical double-shell system with internal damping to a time-dependent surface load is determined by the matrix analysis method. For this purpose, the equations of vibration of the system based upon the Goldenveizer-Novozhilov theory are written as a coupled set of first order differential equations by the use of the state vector of the system. Once the vector has been determined by quadrature of the equations, the steady state response is calculated numerically together with the natural frequencies in terms of the elements of the transfer matrix of the system under any combination of boundary conditions. By the application of the method, the dynamic response and the resonant frequencies (the natural frequencies) are calculated numerically for a double-shell system simply supported at the edges.