Barium titanate stabilized by γ-cyclodextrin nanoparticles were prepared by using a microwave reactor equipped with ultrasonic nozzle mixing at 240°C in a tetraethylene glycol solution of barium ethoxide and titanium ethoxide in the presence of γ-cyclodextrin. Particles in γ-cyclodextrin-stabilized BaTiO3 nanoparticles had an average diameter of 2.1 nm and mainly distributed within the range of about 1 to 4 nm. The γ-cyclodextrin-stabilized BaTiO3 nanoparticles were mixed with 4-cyano-4′-pentylbiphenyl at room temperature resulting in a liquid crystal sol of 4-cyano-4′-pentylbiphenyl. The response time of liquid crystal devices in the presence of γ-cyclodextrin-stabilized BaTiO3 nanoparticles was faster than that in the absence. 相似文献
The purpose in this paper is to prove that there exists a lattice on certain solvable Lie groups and to construct a symplectic solvmanifold with the Hard Lefschetz property, and a locally conformal Kähler solvmanifold. We see that minimal models for these solvmanifolds are formal. 相似文献
A series of diazides of 1,2-diphenylacetylenes was photolyzed in matrices at low temperature and transient photoproducts were characterized by using IR, UV/vis methods combined with ESR studies. Theoretical calculations were also used to understand the experimental findings. The introduction of phenylethynyl groups on phenyl azides has little effect on the photochemical pathway. Thus, upon photoexcitation, (phenylethynyl)phenyl azides afforded the corresponding triplet nitrene, which is in photoequilibrium with the corresponding azacycloheptatetraene. In marked contrast, azidophenylethynyl groups exhibited a dramatic effect not only on the photochemical pathway of phenyl azides but also on the electronic and molecular structure of the photoproducts. The patterns of the effect depended upon the relative position of azide groups in the diphenylacetylene unit. Whenever two azide groups were situated in a conjugating position with respect to each other, as in p,p'-, o,o'-, and p,o'-bis(azides), the azides always resulted in the formation of a quinoidal diimine diradical in which unpaired electrons were extensively delocalizedin the pi-conjugation. The situation changed rather dramatically when azide groups were introduced in the meta position. Thus, the formation of azacycloheptatetraene was noted in the photolysis of the m.m'-isomer. ESR studies indicated the generation of a quintet state that was shown to be a thermally populated state with a very small energy gap of ca. 100 cal mol(-1). The m,p'-isomer was shown to be an excellent precursor for the high-spin quintet dinitrene. The IR spectra of the photoproduct showed no bands ascribable to azacycloheptatetraene. The observed spectra were in good agreement with that calculated for the quintet state. Strong EPR signals assignable to the quintet state were observed, along with rather weak signals due to mononitrenes. Moreover, the quintet bis(nitrene) was rather photostable under these conditions. 相似文献
A river water sample was irradiated with 60Co gamma-rays under aerobic conditions, and the changes of the organic substances in the sample were examined by the analyses of the dissolved organic carbon (DOC), organic composition, UV spectrum and molecular-weight distribution. By the irradiation, the DOC decreased with irradiation dose following the first-order kinetics. In addition, the changes of UV absorption and molecular-weight distribution showed that the considerable decomposition of polymeric aromatic structure, which is the characteristic of humic substances, took place by irradiation of relatively low dose. Since the gamma-ray decomposition does not require any oxidizing agents and pH control, it will cause no compositional change of metallic elements in the water samples and has less chance of contamination. Therefore the method will be useful in, for example, geochemical studies of trace metals in natural waters. 相似文献
Silver nanodimers with a small gap of a few nanometers aligned on glass substrates were used to enhance hyper-Raman scattering of crystal violet dye molecules. When localized surface plasmon of the dimer array was resonantly excited along the interparticle axis, hyper-Raman intensity was significantly enhanced. Moreover, the spectral appearance was slightly different between the two excitation polarizations, suggesting a possibility of two resonance contributions at one-photon and two-photon energies. Since the plasmonic property of dimer arrays can be controlled by the dimer geometry, the dimer arrays are expected to be well-defined substrates for surface-enhanced hyper-Raman spectroscopy. 相似文献
Circularly polarized luminescence (CPL) organic dyes are currently receiving a great interest, but there are still not many reported observations of CPL spectra of hydrophobic dyes from aqueous solution. We have prepared hydrophobic pyrene derivatives and dissolved them into aqueous solutions with γ-cyclodextrin (γ-CD) by using grinding technique. Among these derivatives, (pyrene-1-carbonyl)serine (PySer) forms a spatially restricted dimer in the hydrophobic chiral cavity of γ-CD and exhibits excimer emission with a high quantum yield of Φf?=?0.68. In addition, circular dichroism and CPL signals were induced for the complex. The strong gCPL value of gCPL?=?+?2.2?×?10?3 was obtained, which may be attributed to the interaction between the hydroxyl groups in the side chain of PySer with those of γ-CD and it strengthens the chiral dimeric structure.
Isocyanide—mercuric chloride complexes react readily with an excess of primary and secondary amines to give guanidines and metallic mercury in high yields through a redox decomposition reaction. In the presence of triethylamine, isocyanide—mercuric chloride complexes react with an equimolar amount of a primary amine to give a carbodiimide and metallic mercury. An intermediate organomercuric compound was isolated in the reaction of the isocyanide—mercuric chloride complex with pyrrolidone. 相似文献
A chimeric oligoDNA composed of a natural beta-anomeric oligonucleotide portion and an unnatural alpha-anomeric oligonucleotide portion forms an alternate stranded triplex possessing enhanced thermal stability compared to the triplexes composed of the parental oligomers. 相似文献