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151.
Three new polybrominated 1H‐indoles, compounds 1 – 3 , and three new aristolane sesquiterpenes, compounds 4 – 6 , were isolated from the marine red alga Laurencia similis, together with seven known natural products. Their structures were elucidated on the basis of detailed spectroscopic and mass‐spectrometric analyses, as well as by comparison with literature data. 相似文献
152.
C60和β-叠氮丙酸在氰苯中回流,产物经柱色谱分离、FD-MS证实为五加成C60衍生物,^13C NMR、FT-IR和UV光谱对产物结构进行了表征。 相似文献
153.
Dr. Nai‐Ti Lin Chen‐Yu Xie Shou‐Ling Huang Prof. Chung‐Hsuan Chen Prof. Tien‐Yau Luh 《化学:亚洲杂志》2013,8(7):1436-1440
Trimeric oligonorbornenes with hammock‐like crown ether pendants 3b and 3c were selectively synthesized by cascade metathetical cyclopolymerization upon treatment with the first generation Grubbs catalyst. These crown‐ether‐containing oligonorbornenes are impregnated in egg yolk phosphatidylcholine (EYPC) liposome as an artificial ion channel. The efficiency of the sodium ion transport properties has been examined. Oligomer 3c having a polar hydroxy end group exhibits the highest transport efficiency, which is comparable with the best efficiencies reported in literature. The orientation of the crown ether moieties in these oligomers may be critical for the ion transport properties. 相似文献
154.
A series of octa‐substituted metal phthalocyanines [MPc(OC5H11)8] (M = Co, Ni, Cu, Zn, Pc = phthalocyaninato, (OC5H11)8 = iso‐pentoxy) were obtained from condensation of iso‐pentoxy phthalonitrile in the presence of DBU in n‐pentanol. The compounds were characterized using elemental analysis, IR, and UV/Vis spectra. The crystal structures of all compounds except M = Zn were determined by X‐ray diffraction methods. It was found that the distortion of Pc skeleton come of not only the intra‐molecular steric congestion of bulky substituents, but also the slipped overlaps of the closest molecules. The relations of some bond lengths of the Pc's skeleton to the substituents and central metal atom, as well as the spectroscopic properties are discussed. 相似文献
155.
在两个简化结构模型的基础上,应用NORVIB程序对Ho(TTA)32H2O分子在1650~100cm-1波数范围的振动频率作了指认。在简正频率的计算值与实验值拟合优化后,确定了伸缩、弯曲、面外摇动和扭动等21个力常数以及9个相互作用力常数。计算值与实验值之间的平均偏差为4.75cm-1。 相似文献
156.
In this paper, an evolutionary programming (EP) based fuzzy sliding-mode control (FSMC) is proposed for a magnetic ball suspension system. Firstly, we apply a singular perturbation method to examine a nonlinear model proposed for the magnetic ball suspension system. Secondly, we address design methods of sliding-mode control (SMC), FSMC, and dynamic FSMC. We utilize the EP to adjust scaling factors of the input and output variables for the FSMC. Global asymptotic stability of the EP-based FSMC is confirmed by the Lyapunov stability theory. Finally, simulations on the magnetic ball suspension system are given to show the tracking performances of the proposed control structure. 相似文献
157.
158.
Nai Zhang Weizai Zhang Gaoting Chen Jianhua Xu Zhiwu Liu Zujie Fang 《Chinese Journal of Lasers》1992,(6)
The experimental study of compression of picosecond optical pulses from a gainswitched InGaAsP DFB laser at 1.5μm wavelength range using a Gires-Tournois interferome-ter has been reported. Ultrashort optical pulses with pulsewidths of 6.6 ps, repetition rate of2.4GHz, and peak power in excess of 200 mW are obtained. The characteristics of a Gires-Tournois interferometer as a pulse compressor are also discussed. 相似文献
159.
Ran‐Ran Sun Feng‐Ping Miao Jing Zhang Gang Wang Xiu‐Li Yin Nai‐Yun Ji 《Magnetic resonance in chemistry : MRC》2013,51(1):65-68
Three new xanthone derivatives, yicathin A (1), yicathin B (2), and yicathin C (3), and three known anthraquinone derivatives, alatinone (4), 1,5‐dihydroxy‐3‐methoxy‐7‐methylanthraquinone (5), and 5‐hydroxy‐1,3‐dimethoxy‐7‐methylanthraquinone (6), were isolated from the cultures of Aspergillus wentii pt‐1, an endophytic fungus isolated from the marine red alga Gymnogongrus flabelliformis. Their structures were unambiguously elucidated by NMR and mass spectroscopic methods as well as quantum chemical calculations. Compound 2 was active against Escherichia coli, and 3 could inhibit E. coli, Staphylococcus aureus, and Colletotrichum lagenarium. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
160.
Hai Yang Yu San Lin Jin Xue Zhang Yuan Liu Yang Fu Ou Nai Li Wang Xin Sheng Yao 《中国化学快报》2009,20(4):459-461
Two new benzophenone glucosides were isolated from the 60%ethanol extract of the dried stems of Cratoxylum cochinchinense. The structures were elucidated as 3-O-β-D-glucopyranosyl-2′,4,6′-trihydroxy-benzophenone and 3-O-β-D-glucopyranosyl-2′,5,6′-trihydroxybenzophenone on the basis of spectral and chemical methods. 相似文献