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51.
A series of 4-(4-n-heptoxy-2,3-difluorophenylethynyl)phenyl 3-nitro-4-polyfluoroalkoxybenzoate liquid crystals was synthesized and their phase transition behaviours were studied by optical polarizing microscopy and DSC. The results show that the mesogens containing long polyfluoroalkoxy chain tend to exhibit the smectic A phase. 相似文献
52.
Kei Fujise Dr. Eiji Tsurumaki Prof. Dr. Kan Wakamatsu Prof. Dr. Shinji Toyota 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(14):4548-4552
Polycyclic aromatic compounds consisting of four or five fused anthracene units were synthesized by PtCl2-catalyzed cycloisomerization as novel long expanded helicenes. These compounds have helical structures with significant stacking of the terminal anthracene moieties at 0.33 nm interlayer distance. In the UV-vis and fluorescence spectra, the absorption and emission bands were red-shifted as the number of fused anthracene units was increased. The characteristic broad and long-lived emission bands of the long analogues are explained by the excimer-like stabilization of the excited state. These photophysical data as well as their cyclic voltammetric data are discussed on the basis of the π-conjugation and interlayer π⋅⋅⋅π interactions in the molecular structures and the molecular orbitals. The barrier and mechanism of helical inversion are also reported. 相似文献
53.
Two resorcyl di[4-(4-alkoxy-2,3-difluorophenyl)ethynyl]benzoate liquid crystals were prepared and their mesomorphic properties observed and measured. Achiral antiferroelectric phases were seen with increasing length of the hydrocarbon terminal chains. 相似文献
54.
One series of two-ring and two series of three-ring mesogens with 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10-heptadecafluorodecaoxy terminal chains containing tolane or biphenyl units have been synthesized. Their mesomorphic properties were observed and measured by optical polarizing microscopy and differential scanning calorimetry. The three-ring mesogens only exhibit a wide smectic C phase when the length of their hydrocarbon chains is intermediate. 相似文献
55.
A practical and scalable synthesis of ethyl (R)-piperidine-3-acetate was achieved from commercially available 3-pyridylacetic acid in 76% overall yield. The practical synthesis was demonstrated on 100-g scale. One-pot reductive N-ethylation of the pyridinium salt with acetonitrile gave an N-ethyl piperidine derivative. 相似文献
56.
V. N. Petrov A. B. Ustinov N. S. Kan D. V. Petrova A. A. Grib 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2014,8(3):470-476
A concept for the experimental study of the physical properties of entangled electron spin states in a solid body is proposed. The construction of the experimental setup is developed. New-generation electron spin detectors are created. Test measurements of the electron spin polarization by two simultaneously operating Mott detectors are carried out. It is found that Bell’s inequalities are satisfied in the traditional measurement mode (without time coincidences of the pulses). 相似文献
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Effects of shell composition,dosage and alkali type on the morphology of polymer hollow microspheres
Polymer hollow microspheres were prepared by performing alkali treatment on the multilayer core/shell polymer latex particles containing carboxyl groups. Effects of the shell composition and dosage as well as alkali type on the morphology of the microspheres were investigated. Results showed that in comparison with acrylonitrile(AN) and methacrylic acid(MAA), using butyl acrylate(BA) as the shell co-monomer decreased the glass transition temperature(T_g) of shell effectively and was beneficial to the formation of uniform and big hollow structure. Along with the increase of the shell dosage, the alkali-treated microspheres sequentially presented porous and hollow morphology, and the size of microspheres increased, while the hollow diameter increased first and then decreased, and the maximum hollow ratio reached 39.5%. Furthermore, the multilayer core/shell microspheres had better tolerance to NH_3·H_2O than to NaOH. When the molar ratio of alkali to methacrylic acid(MR_(alkali/acid)) for Na OH ranged from 1.15 to 1.30 or MRalkali/acid for NH_3·H_2O ranged from 1.30 to 2.00, the regular polymer hollow microspheres could be obtained. 相似文献