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281.
Terazima M 《Physical chemistry chemical physics : PCCP》2011,13(38):16928-16940
A recently developed method to monitor reaction kinetics of intermolecular interaction is presented in this perspective. This method is based on time-dependent diffusion coefficient measurements using the pulsed laser induced transient grating technique. Using this method, time dependent biomolecular interactions, such as transient association and dissociation reactions in solution, have been successfully detected in real time. The principles and particular applications are described. In particular, unique features of this time-dependent diffusion coefficient method are emphasized by comparison with other techniques. 相似文献
282.
We completely clarify the feature of primordial non-Gaussianities of tensor perturbations in the most general single-field inflation model with second-order field equations. It is shown that the most general cubic action for the tensor perturbation h(ij) is composed only of two contributions, one with two spacial derivatives and the other with one time derivative on each h(ij). The former is essentially identical to the cubic term that appears in Einstein gravity and predicts a squeezed shape, while the latter newly appears in the presence of the kinetic coupling to the Einstein tensor and predicts an equilateral shape. Thus, only two shapes appear in the graviton bispectrum of the most general single-field inflation model, which could open a new clue to the identification of inflationary gravitational waves in observations of cosmic microwave background anisotropies as well as direct detection experiments. 相似文献
283.
We report on the detection of picosecond pulsed squeezed light generated by an optical parametric amplification in a periodically poled MgO:LiNbO(3) waveguide. By using a temporally shaped local oscillator in a balanced homodyne detection, we obverved the squeezing of -5.0 dB below the shot noise level. The squeezing level at the exit of the waveguide was estimated to be -9.7±0.8 dB. 相似文献
284.
285.
Yoshinobu Naoshima Charles E. Carraher Jr. Timothy J. Gehrke Masahide Kurokawa David Blair 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(7):861-873
Abstract Dextran was modified through condensation with biscyclopentadienyltitanium dichloride and dibutyltin dichloride by employing a number of solution and interfacial condensation systems. The modified dextran is rapidly synthesized (within 30 s) in good yield with moderate to high degrees of substitution. The products are complex with chains composed of a variety of substituted and un-substituted glycopyranose units. 相似文献
286.
Pore alignment and linker orientation influence diffusion and guest molecule interactions in metal–organic frameworks (MOFs) and play a pivotal role for successful utilization of MOFs. The crystallographic orientation and the degree of orientation of MOF films are generally determined using X-ray diffraction. However, diffraction methods reach their limit when it comes to very thin films, identification of chemical connectivity or the orientation of organic functional groups in MOFs. Cu-based 2D MOF and 3D MOF films prepared via layer-by-layer method and from aligned Cu(OH)2 substrates were studied with polarization-dependent Fourier-transform infrared (FTIR) spectroscopy in transmission and attenuated total reflection configuration. Thereby, the degrees for in-plane and out-of-plane orientation, the aromatic linker orientation and the initial alignment during layer-by-layer MOF growth, which is impossible to investigate by laboratory XRD equipment, was determined. Experimental IR spectra correlate with theoretical explanations, paving the way to expand the principle of IR crystallography to oriented, organic–inorganic hybrid films beyond MOFs.Polarization-dependent infrared spectroscopy of oriented metal organic framework films fills the information gap left by diffraction methods and gives access to the orientation of the aromatic linker and initial orientation of ultra-thin films. 相似文献
287.
Masahide Tominaga Akitaka Iekushi Kosuke Katagiri Kazuaki Ohara Kentaro Yamaguchi Isao Azumaya 《Tetrahedron letters》2014
Three tetrapodal adamantanes bearing imidazole (1), benzimidazole (2), and phenylimidazole (3) moieties were designed and synthesized. The co-crystallization of polyethylene glycol (PEG) and tetrapodal molecules provided polymer-inclusion organic crystals (1a–3a). Single crystal X-ray analysis revealed that organic networks possessing various channels were produced by CH/N and CH/π interactions. The PEG chain had zigzag, kink-type, and helical conformations. 相似文献
288.
Masu H Katagiri K Kato T Kagechika H Tominaga M Azumaya I 《The Journal of organic chemistry》2008,73(13):5143-5146
A novel chiral spherical molecule composed of aromatic amide was synthesized in short steps. The molecule is constructed from four benzene rings connected by six amide bonds and has multiple functionalizable points and an asymmetric structure. The racemic spherical molecule constructed channel network structures in the crystalline state. 相似文献
289.
Minami Ebe Asuka Soga Kaiyu Fujiwara Brian J. Ree Hironori Marubayashi Katsumi Hagita Atsushi Imasaki Miru Baba Takuya Yamamoto Kenji Tajima Tetsuo Deguchi Hiroshi Jinnai Takuya Isono Toshifumi Satoh 《Angewandte Chemie (International ed. in English)》2023,62(35):e202304493
Rotaxanes consisting of a high-molecular-weight axle and wheel components (macro-rotaxanes) have high structural freedom, and are attractive for soft-material applications. However, their synthesis remains underexplored. Here, we investigated macro-rotaxane formation by the topological trapping of multicyclic polydimethylsiloxanes (mc-PDMSs) in silicone networks. mc-PDMS with different numbers of cyclic units and ring sizes was synthesized by cyclopolymerization of a α,ω-norbornenyl-functionalized PDMS. Silicone networks were prepared in the presence of 10–60 wt % mc-PDMS, and the trapping efficiency of mc-PDMS was determined. In contrast to monocyclic PDMS, mc-PDMSs with more cyclic units and larger ring sizes can be quantitatively trapped in the network as macro-rotaxanes. The damping performance of a 60 wt % mc-PDMS-blended silicone network was evaluated, revealing a higher tan δ value than the bare PDMS network. Thus, macro-rotaxanes are promising as non-leaching additives for network polymers. 相似文献
290.
Spherical aggregates of palladium nanoparticles were produced by stirring palladium(II) acetate with dendritic molecules (i.e., octa(3-aminopropyl)silsesquioxane octahydrochloride (POSS-NH3+) or the amine-terminated G1.0 poly(amidoamine) dendrimer (G1-NH2)) in methanol at room temperature via self-organized spherical templates of Pd(OAc)2 and the dendritic molecule. The mixing ratio of the terminal amino groups of the dendritic molecule and palladium ions (Z=[Pd2+]/[-NH2]) affected the formation of the spherical aggregates of palladium nanoparticles. Maximum Z values with no reduction of palladium ions (the solution remained yellow) were 1.0 for POSS-NH3+ and 1.6 for G1-NH2, respectively. TEM observations suggested that the density of the palladium nanoparticles in the aggregates using POSS-NH3+ as a template was higher than that using G1-NH2. From tapping mode atomic force microscopy, shapes of the aggregates using POSS-NH3+ and G1-NH2 were a spherical form and an oval form on plates, respectively. Increasing the rigidity of the silsesquioxane core of the dendritic molecules increased the stability of the spherical form in the dry state. 相似文献