Three‐dimensional hydrogen‐bonded framework structures in flunarizinium nicotinate and flunarizinediium bis(4‐toluenesulfonate) dihydrate

The structures of two salts of flunarizine, namely 1‐bis[(4‐fluorophenyl)methyl]‐4‐[(2E)‐3‐phenylprop‐2‐en‐1‐yl]piperazine, C₂₆H₂₆F₂N₂, are reported. In flunarizinium nicotinate {systematic name: 4‐bis[(4‐fluorophenyl)methyl]‐1‐[(2E)‐3‐phenylprop‐2‐en‐1‐yl]piperazin‐1‐ium pyridine‐3‐carboxylate}, C₂₆H₂₇F₂N₂⁺·C₆H₄NO₂⁻, (I), the two ionic components are linked by a short charge‐assisted N—H...O hydrogen bond. The ion pairs are linked into a three‐dimensional framework structure by three independent C—H...O hydrogen bonds, augmented by C—H...π(arene) hydrogen bonds and an aromatic π–π stacking interaction. In flunarizinediium bis(4‐toluenesulfonate) dihydrate {systematic name: 1‐[bis(4‐fluorophenyl)methyl]‐4‐[(2E)‐3‐phenylprop‐2‐en‐1‐yl]piperazine‐1,4‐diium bis(4‐methylbenzenesulfonate) dihydrate}, C₂₆H₂₈F₂N₂²⁺·2C₇H₇O₃S⁻·2H₂O, (II), one of the anions is disordered over two sites with occupancies of 0.832 (6) and 0.168 (6). The five independent components are linked into ribbons by two independent N—H...O hydrogen bonds and four independent O—H...O hydrogen bonds, and these ribbons are linked to form a three‐dimensional framework by two independent C—H...O hydrogen bonds, but C—H...π(arene) hydrogen bonds and aromatic π–π stacking interactions are absent from the structure of (II). Comparisons are made with some related structures.     

基于时间和渠道敏感顾客选择偏好的双渠道定价策略

随着网络技术的发展,带动了网络销售模式的发展。网络渠道为顾客带来了便利性,也为制造商提供了扩大市场占有率和提高利润的机会,如何合理定价关系到企业的长久发展。在考虑顾客对网络渠道交付时间和网络渠道接受敏感的基础上,研究了制造商的单渠道和双渠道定价策略问题。研究结果表明,两种销售模式下零售渠道的定价相同,而网络渠道的定价低于零售渠道的定价。制造商可以通过引入网络渠道提高市场占有率、降低顾客时间敏感性和提高网络渠道接受程度,从而提高利润。最后,通过数值实验分析了交付时间敏感性和网络渠道接受程度对企业决策的影响,并对比分析了单渠道和双渠道的最优决策。     

Experimental study in correlation variation of acoustic propagation channel in Philippine sea

I.IntroductionSonarsignalisoftcndistortcdbythcwcightingofthcacousticchanncl'stransfcrfunction.Inthiscase,therearetwosonarsignaIproccssingmcthodswhichcanbcuscdtodccrcascthedistortionofthcsignal.Oneisthcsclcctionofamorcto1crantsignalwithcorrcspondingsigna1proeessingmethod.Forexamp1e,astcpfrcqucncymodulatcdsignalwithpostintcgratcdpro-ccssingcanbeusedinthiscasc.Theanothcrisobtainingthcrcsponscfunctionofthcacousticchanne1andmatchingitwithamatehfiltCr.Bothofthcscmcthodsrcquirethcstudyofhme-frequen…     

单通道实现三级Clipped模型的光学神经网络系统

提出并采用单通道光学系统实现了三级Clipped模型的神经网络,并用统计方法计算了三级Clipped模型的存储容量,和Clipped模型相比,三级Clippdd模型有更强的存储与寻址能力.     

The Effect of Exposure Duration on Stereopsis and Its Dependency on Spatial Frequency

To investigate the effect of exposure duration on stereopsis and its spatial frequency dependency, we measured disparity threshold for the depth discrimination varying stimulus exposure duration between 0.05 and 2 s for three spatial frequencies (0.23, 0.94 and 3.75 c/deg). The results showed that disparity threshold decreased with increase in exposure duration up to a certain duration, beyond which it was approximately constant (the duration is called critical duration). The critical duration was about 150 ms for gratings with low and middle spatial frequencies (0.23 and 0.94 c/deg) while the duration was about 750 ms for gratings with high spatial frequency (3.75 c/deg). This suggests that temporal integration property varies dependently on stimulus spatial frequency. We also attempted to relate the spatial frequency dependency of the temporal integration property to the differences in temporal frequency tuning to different spatial frequency stimuli.     

A remark on the pressure for the Navier–Stokes flows in 2‐D straight channel with an obstacle

Let T=?×(‐1,1) and &ℴ??² be a smoothly bounded open set, closure of which is contained in T. We consider the stationary Navier–Stokes flows in . In general, the pressure is determined up to a constant. Since Ω has two extremities, we want to know if we can choose the constant same. We study the behaviour of the pressure at the infinity in Ω and give a relation between the velocity and the pressure difference. Copyright © 2004 John Wiley & Sons, Ltd.     

Adsorption and Mobility of Water and Benzene Molecules in Carbon and Polymer Adsorbents

The correlation between the adsorption and the mobility of adsorbed molecules was analyzed. The peculiarities of molecular mobility in microporous adsorbents with relatively rigid (active carbons) and non-rigid (polymer super-crosslinked and methacrylate sorbents) structure were studied using pulsed nuclear magnetic resonance (NMR) techniques. It was shown that the translational behavior of water and benzene in pores are connected with the specific adsorption mechanism. The NMR data allowed analyzing the changes of molecular state in the processes of adsorption. Diffusional properties of water molecules in the super-crosslinked polystyrenes and active carbons with relatively rigid framework are similar and differ from that in methacrylate polymer sorbents. Moreover, the results of NM relaxation measurements allowed analyzing the porous structure over the scale of pore sizes, while the scale of the self-diffusion measurements comprises the areas of different porosity. The NMR data agree well with the data of adsorption measurements and complement them. Dedication: This work is devoted to memory of the professor W. Schirmer.     

光突发交换中交换矩阵配置时间的影响研究

光突发交换是近几年出现的一种很有前途的交换技术。在光突发交换网络的核心节点中,光交换矩阵是一个关键部件,其配置时间影响到光突发交换网络的性能。这种影响表现在对数据信道可用时间施加了限制。在考虑光交换矩阵配置时间的基础上给出了修正后的LAUC算法,并通过计算机仿真研究了这种配置时间对光突发交换性能的影响。结果表明,光交换矩阵配置时间的增大会导致输出数据信道利用率的降低,进而增大了数据丢失率。     

Gate control characteristics in GaAs nanometer-scale Schottky wrap gate structures

Gate control characteristics of GaAs-based quantum wire transistors (QWRTrs) controlled by a nanometer-scale Schottky wrap gate (WPG) are investigated theoretically and experimentally. Gate bias dependence of the effective wire width of fabricated WPG QWRTrs determined theoretically as well as experimentally from Landau plots showed that the nanometer-scale WPG controls the potential very tightly near channel pinch-off and that the pinch-off threshold voltage is strongly dependent on the gate length, L_G, when L_G is shorter than 400 nm. The theory based on the three-dimensional (3D) potential simulation pointed out that Fermi level pinning on the semiconductor surface around the WPGs strongly affects the gate controllability in the nanometer-scale Schottky WPG structure.