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61.
Milan CH. Dutta Kaushik Chanda Jai N. Vishwakarma 《Journal of heterocyclic chemistry》2005,42(1):121-123
A facile one‐pot synthetic strategy has been developed for novel [alkanediylbis(3‐alkyl/aralkyl/ aryl‐3,6‐dihydropyrimidine‐1,5(2H)‐diyl)]bis(arylmethanones) 2a‐c, 2e‐m and [1,4‐phenylenebis(3‐phenyl‐3,6‐dihydropyrimidine‐1,5(2H)‐diyl)]bis(phenylmethanone) 2d by refluxing enaminones 1a‐f in methanol with diamines and formaldehyde. 相似文献
62.
İhsan Çalış Ayşegül Güvenç Metin Armağan Mehmet Koyuncu Charlotte H. Gotfredsen Søren R. Jensen 《Helvetica chimica acta》2007,90(8):1461-1466
From the aerial parts of Eremostachys moluccelloides Bunge , a new iridoid glucoside, lamalbidic acid ( 7 ), was isolated as its choline salt 7a together with six known iridoid glucosides, 5‐deoxysesamoside ( 1 ), 6β‐hydroxy‐7‐epiloganin ( 2 ), lamalbide ( 3 ), shanzhiside methyl ester ( 4 ), sesamoside ( 5 ), and 5‐deoxypulchelloside I ( 6 ). The structures of 7a and 7 (obtained from 7a ) were elucidated by spectroscopic (UV, IR, 1D‐ and 2D‐NMR, and ESI‐MS) methods. 相似文献
63.
Funda Nuray Yalçın Tayfun Ersöz Kürşat Avcı Charlotte H. Gotfredsen Søren R. Jensen İhsan Çalış 《Helvetica chimica acta》2007,90(2):332-336
Two new iridoid glycosides, eriobioside ( 1 ) and lamerioside ( 2 ), were isolated from the aerial parts of Lamium eriocephalum subsp. eriocephalum, along with the two known compounds lamiide ( 3 ) and ipolamiide ( 4 ). Their structures were elucidated by spectroscopic methods (UV, 1D‐ and 2D‐NMR) and by mass spectrometry (HR‐ESI‐MS). 相似文献
64.
65.
P. R. Willmott C. M. SchlepÜTz R. Herger B. D. Patterson O. Bunk CH. Brönnimann 《Synchrotron Radiation News》2013,26(2):16-22
The intense flux delivered by third-generation synchrotron sources has opened up exciting new possibilities in surface diffraction (SD) studies [1–3]. Nonetheless, practical SD experiments are plagued by several technical problems. Because the crystalline surface is typically probed down to a depth of approximately 1 or 2 nm when using subcritical-angle incident X-ray beams, the scattering volume is only about 10-12 cm3. This is further exacerbated by the fact that the most interesting information on the surface structure is generally obtained from those regions of diffraction features known as crystal truncation rods (CTRs) where scattering is weakest, i.e., in between Bragg peaks. 相似文献
66.
67.
A. Mikułko M. Marzec M. Wierzejska R. Douali CH. Legrand S. Wróbel 《Phase Transitions》2013,86(6-7):585-594
In this article the physical properties of hexatic phases of three substances MHPNBC, FOOPP and FNHPP have been studied by differential scanning calorimetry, texture observation and dielectric spectroscopy. Experimental results are discussed from the point of view of existing theories. It is interesting that two of the substances studied, the FOOPP and FNHPP, exhibit enhanced spontaneous polarization in the highly ordered SmI* phase and show a jump of the spontaneous polarization in the vicinity of the SmC*–SmI* transition. In the SmI* phase of FOOPP a very high value of spontaneous polarization of the order of 530?nC?cm?2 was found. Based on the results obtained the macroscopic and microscopic properties of the hexatic phases are discussed. 相似文献
68.
The existence of triple solutions for a second-order nonlocal functional boundary value problem is proved by using a fixed-point theorem on cones in Banach spaces due to Leggett and Williams. The obtained results are new even in the ordinary case for three-point boundary value problems discussed quite recently in [Xiaoming He and Weigao Ge (2002). Triple solutions for second-order three-point boundary value problems. J. Math. Anal. Appl., 268, 256–265]. 相似文献
69.
The expansion theorem of quantum field theoy relating Heisenberg operators to asymptotic free-field operators is rewritten by means of the time-path technique, originally due to Schwinger, which to date has only found application in statistical mechanics. The theorem is combined with Bogoliubov's initial condition of vanishing correlations in the infinite past to rederive Keldysh's perturbation scheme for non-equilibrium statistical Green's functions. 相似文献
70.
CH. B. Tsvetanov D. T. Dotcheva 《Journal of polymer science. Part A, Polymer chemistry》1986,24(9):2253-2259
The electro-chemical characteristics of isobutyronitrile lithium (P1Li) and 2-lithio-4-cyano-2,4-dimethylpentanenitrile (P2Li) are studied. The dissociation constants K of P1Li and P2Li are of the order of 10?11M and show that in THF mainly contact ion pairs exist. The lower value of K for P2Li is an indication for intramolecular complexation between the counterion and the cyano group, next to the active center. Both compounds tend to form ion triples. The results obtained show that in THF the nitrile group of the second monomer unit participates both in intra- and intermolecular interactions with the counterion. 相似文献