Conformational peculiarities of alcohols incorporated in lyotropic and thermotropic liquid crystals

Conformational characteristics of 1-butanol incorporated not only in hexagonal and lamellar aggregates formed by a lyotropic liquid crystal composed of sodium octanoate, 1-butanol, and water but also in a thermotropic liquid crystal, 4'-methoxybenzylidene-4-n-butylaniline (MBBA), have been investigated from 2H NMR quadrupolar splittings of the perdeuterated and partially deuterated compounds. In the lyotropic phases, 1-butanol shows strong trans preferences and renders itself extended, and octanoate decreases the trans fraction toward the methyl terminal to fill the inner space of the aggregate on behalf of 1-butanol. In MBBA, 1-butanol prefers globular conformations. This tendency was also indicated from the phase behaviors of 1-butanol/MBBA and 1-decanol/MBBA systems. In the nematic field, two successive C-C bonds of 1-butanol mostly adopt g+/-g+/- conformations, which are formed in the vicinity of the headgroup of 1-decanol in the lamella of the sodium octanoate/1-decanol/water system. A large degree ofconformational freedom near the hydroxyl group of alcohols, being shown by ab initio molecular orbital calculations at the Gaussian-2 level, permits them to change conformation for each environment.     

Dynamical properties of ethylene glycol and glucose studied by temperature-modulated differential scanning calorimetry and Brillouin scattering

The fragility of ethylene glycol and glucose aqueous solution systems has been investigated by temperature-modulated differential scanning calorimetry (TMDSC). The frequency and temperature dependences of complex specific heat have been observed in the vicinity of a glass-transition temperature T _g . It is shown that the value of the fragility index m can be determined from the temperature dependence of the α-relaxation times observed by TMDSC. We have also studied the elastic properties of these aqueous solutions by micro-Brillouin scattering, and determined these relaxation times of elastic properties in the gigahertz range.     

Measurement of the Magnetic Moment of the First Excited State in 93Sr Using on-line TDPAC technique

The g-factor of the first excited state of ⁹³Sr (E = 213 keV, T _1/2 = 4.6 ns) was measured by an on-line TDPAC technique with use of the strong hyperfine field in Fe metal. The Larmor frequency ω _L = (2.60 ± 0.15) × 10⁸ rad/s was obtained. The g-factor is derived as g = −0.227 ± 0.013 from g = −ℏω _L/B _hf μ _N. If the spin of the first excited state of ⁹³Sr is assumed to be 3/2, the g-factor is predicted by a simple core-excitation model as g = −0.22, which is in good agreement with the present experimental result.     

Awareness, Belief, and Communication Reaching Consensus

This article studies graph-theoretical conditions under which communication will lead to consensus among players about their decisions in circumstances where there are more than two players and they interact in pair without public announcement. It is shown that consensus on their decisions can be guaranteed if the communication graph contains no cycle. Where none of the requirements for player's knowledge is imposed as in the standard model of knowledge with partitional information structure.     

Predictive elucidation of conformational characteristics and configurational properties of poly(1-methylphosphirane) and poly(1-phenylphosphirane) as a molecular design

Conformational characteristics and configurational properties of poly(1-methylphosphirane) (PMePP) and poly(1-phenylphosphirane) (PPhPP) have been predictively elucidated by the refined rotational isomeric state scheme coupled with ab initio molecular orbital and density functional calculations. The lone pair of the phosphorus atom adopts an sp hybrid orbital. Owing to the high s character (50%), the polyphosphiranes exhibit low proton (hydrogen) affinities, and hence the lone pair does not form any intramolecular attractive interactions with hydrogen. As the meso-diad probability varies from 0 (syndiotactic) to 1 (isotactic), the characteristic ratio of PMePP slightly increases from 6.7 to 7.4, whereas that of PPhPP considerably decreases from 38 to 7.3. The large dimension of syndiotactic PPhPP is chiefly due to π-π attractions formed between adjacent phenyl groups. The trivalent phosphorus atom may be bonded to heavy, noble, and transition metals but readily or gradually oxidized. The usefulness and necessity of the polyphosphiranes have been assessed.     

Small-angle x-ray scattering of distorted lamellar structures

Small-angle x-ray scattering (SAXS) intensity for the lamellar structure of polymeric materials has been formulated with consideration of structural defects such as the finiteness of the lamellar stack, the lamellar bend, and the paracrystalline distortions. In particular, the effects of the lamellar bend on the SAXS profile have been elucidated on the basis of Vonk'xss formula γ₁(x) – γ(x)exp(?2x/d). Here, the scattering profile due to the lamellar bend is shown to be expressed by a Cauchy function. The integral breadth is equal to 2π/d, being independent of the order of scattering. As an example of the SAXS analysis based on the theory, the characterization of the lamellar structure in the “hard” elastic polypropylene films is reported. The long period and the lamellar thickness are evaluated from the correlation function, and the distortion length and Hosemann's g factor are estimated according to the procedure presented here. On the basis of these structural parameters, the relationship between the manufacturing process and the lamellar structure of the polypropylene films is discussed. © 1993 John Wiley & Sons, Inc.     

Structure-property relationships of polyselenoethers [-(CH2)ySe-]x (y=1, 2, and 3) and related polyethers and polysulfides

Conformational characteristics, solution (melt) properties, and thermal properties of polyselenoethers [-(CH2)ySe-]x ( y=1, 2, and 3) have been revealed by the rotational isomeric state analysis of ab initio molecular orbital calculations and (1)H and (13)C NMR experiments for monomeric model compounds and compared with those of typical polyethers and polysulfides. The comparative results are summarized here as correlations in conformation among model compounds and unperturbed and crystalline states of the polymers, and thermal properties of the polymer crystals are discussed in terms of intramolecular and intermolecular interactions. By ab initio molecular orbital calculations under periodic boundary conditions, helical structures of poly(methylene oxide), poly(methylene sulfide), and poly(methylene selenide), and the crystal structure of poly(ethylene selenide) have been optimized, and their electronic structures have been predicted. A systematic methodology to predict and characterize up to higher-order structures and various physical properties of polymers incorporated in different phases has been attempted to be developed.     

Hyperfine Interaction of 140Ce(←140La) in CaB6

A ¹⁴⁰La(I ^π=3⁻, T _1/2=40.3 h)-doped layer has been produced in CaB₆ by means of radioactive isotope (RI) beam technique: ¹⁴⁰Cs(I ^π=1⁻, T _1/2=63.7 s) was implanted into CaB₆ and the radioactive equilibrium of ¹⁴⁰Ba–¹⁴⁰La was achieved. The concentration of La in CaB₆ was La/Ca ∼0.001. Obtained TDPAC spectra of the 2083 keV level of ¹⁴⁰Ce (I ^π=4⁺, T _1/2=3.4 ns, μ=+4.35±0.10 μ _N ) followed by the β decay of ¹⁴⁰La showed the existence of hyperfine magnetic fields: B _hyp=−15.0±0.5 T and −1.00±0.15 T. This revised version was published online in September 2006 with corrections to the Cover Date.     

3-Colorable Even Embeddings on Closed Surfaces

It is known that for any closed surface F², every even embedding on F² with sufficiently large representativity is 4-colorable. In this paper, we shall characterize 3-colorable even embeddings on F² with sufficiently large representativity.