排序方式: 共有17条查询结果,搜索用时 15 毫秒
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Jeremy G. Finden Eagranie Yuh Christa Huntley Robert P. Lemieux 《Liquid crystals》2007,34(9):1095-1106
A series of axially chiral 5,5'- and 6,6'-dialkanoyloxy-2,2'-spirobiindan-1,1'-dione dopants, (R)-2 and (R)-4a-4c were synthesized in optically pure form and their ferroelectric polarization powers, δp, measured in four liquid crystal hosts with isotropic (I)-nematic (N)-smectic A (SmA)-smectic C (SmC) phase sequences. The results show that the sign of polarization P S induced by (R)-2 and (R)-4a-4c follows the same trend as that previously reported for the 5,5'- and 6,6'-diheptyloxy-2,2'-spirobiindan-1,1'-dione dopants, (R)-1 and (R)-3. The polarization induced by (R)-2 in the host DFT is below detection limits, and the sign of P S was found to invert as a function of temperature at mole fractions as low as 0.01. On the other hand, the polarization power of the 6,6'-diheptanoyloxy dopant (R)-4b in the host NCB76 is -1449 nC cm-2, the fourth highest value reported so far, and more than three times the δp value of the 5,5'-diheptanoyloxy analogue (R)-2 in that host (+474 nC cm-2). Results of 2H NMR experiments suggest that (R)-4b exerts stronger local perturbations in NCB76 than (R)-2, and that these perturbations may be chiral in nature. 相似文献
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This paper discusses various aspects of Hermite–Birkhoff interpolation that involve prescribed values of a function and/or its first derivative. An algorithm is given that finds the unique polynomial satisfying the given conditions if it exists. A mean value type error term is developed which illustrates the ill-conditioning present when trying to find a solution to a problem that is close to a problem that does not have a unique solution. The interpolants we consider and the associated error term may be useful in the development of continuous approximations for ordinary differential equations that allow asymptotically correct defect control. Expressions in the algorithm are also useful in determining whether certain specific types of problems have unique solutions. This is useful, for example, in strategies involving approximations to solutions of boundary value problems by collocation. 相似文献
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Jeremy Finden Gavin Beck Andrea Lantz Rosa Walsh Michael J. Zaworotko Robert D. Singer 《Journal of chemical crystallography》2003,33(4):287-295
Attempts to prepare novel air and moisture stable room-temperature ionic liquids have afforded a new 1,3-dialkylimidazolium tetraarylborate salt: 1-butyl-3-methylimidazolium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate, [bmim]BARF, 1. Crystal data: C80
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2F48N4, monoclinic space group P2(1)/n, a = 21.2622(17) Å, b = 15.8037(13) Å, c = 26.227(2) Å, = 101.841(2) , V = 8625.3(12) Å3, Z = 1.544. 相似文献
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B Salimbahrami B Lohmann T Bechtold JG Korvink 《Mathematical and Computer Modelling of Dynamical Systems: Methods, Tools and Applications in Engineering and Related Sciences》2013,19(1):79-93
In this paper we introduce a two-sided Arnoldi method for the reduction of high order linear systems and we propose useful extensions, first of all a stopping criterion to find a suitable order for the reduced model and secondly, a selection procedure to significantly improve the performance in the multi-input multi-output (MIMO) case. One application is in micro-electro-mechanical systems (MEMS). We consider a thermo-electric micro thruster model, and a comparison between the commonly used Arnoldi algorithm and the two-sided Arnoldi is performed. 相似文献
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Munshi G Mustafa Sudhir Raniwala T Awes B Rai RS Bhalerao JG Contreras RV Gavai SK Ghosh P Jaikumar GC Mishra AP Mishra H Mishra B Mohanty J Nayak J-Y Ollitrault SC Phatak L Ramello R Ray PK Sahu AM Srivastava DK Srivastava VK Tiwari 《Pramana》2006,67(5):961-981
This is the report of Heavy Ion Physics and Quark-Gluon Plasma at WHEPP-09 which was part of Working Group-4. Discussion and
work on some aspects of quark-gluon plasma believed to have created in heavy-ion collisions and in early Universe are reported. 相似文献
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A series of axially chiral 5,5′‐ and 6,6′‐dialkanoyloxy‐2,2′‐spirobiindan‐1,1′‐dione dopants, (R)‐2 and (R)‐4a–4c were synthesized in optically pure form and their ferroelectric polarization powers, δp, measured in four liquid crystal hosts with isotropic (I)–nematic (N)–smectic A (SmA)–smectic C (SmC) phase sequences. The results show that the sign of polarization P S induced by (R)‐2 and (R)‐4a–4c follows the same trend as that previously reported for the 5,5′‐ and 6,6′‐diheptyloxy‐2,2′‐spirobiindan‐1,1′‐dione dopants, (R)‐1 and (R)‐3. The polarization induced by (R)‐2 in the host DFT is below detection limits, and the sign of P S was found to invert as a function of temperature at mole fractions as low as 0.01. On the other hand, the polarization power of the 6,6′‐diheptanoyloxy dopant (R)‐4b in the host NCB76 is ?1449 nC cm?2, the fourth highest value reported so far, and more than three times the δp value of the 5,5′‐diheptanoyloxy analogue (R)‐2 in that host (+474 nC cm?2). Results of 2H NMR experiments suggest that (R)‐4b exerts stronger local perturbations in NCB76 than (R)‐2, and that these perturbations may be chiral in nature. 相似文献