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991.
Sie Tiong Ha Teck Leong Lee Siew Ling Lee Guan Yeow Yeap Yip Foo Win Siew Teng Ong 《中国化学快报》2012,23(2):177-180
A homologous series of azomethine esters,4-n-alkanoyloxybenzylidene-4’-bromoanilines possessing even number of carbon atoms at the terminal alkanoyloxy chain(Cn-1H2n-1COO- n = 8,10,12,14,16,18) was synthesized and characterized.Whilst n-octanoyloxy to n-dodecanoyloxy derivatives exhibited enantiotropic smectic A and smectic B phases,n-tetradecanoyloxy to n-octadecanoyloxy derivatives possessed enantiotropic smectic A and monotropic smectic B properties.n-Decanoyloxy derivatives demonstrated the optimum exhibition for both smectic A and smectic B phases.It was found that the length of terminal alkanoyloxy chain has an influence on mesomorphic properties. 相似文献
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Xue Liu Wenbi Guan Xiaoli Wu Hongyan Zhang 《International journal of environmental analytical chemistry》2013,93(11):1073-1084
A modified QuEChERs method with liquid chromatography-tandem mass spectrometry for analysis of guadipyr residue and dissipation in rice matrices, paddy soil and paddy water was developed and validated. Mean recoveries and relative standard deviations in paddy soil, paddy water, rice plant, rice straw, rice hull and husked rice matrices at three spiking levels were 83.1–116.5% and 1.6–9.5%, respectively. The half-life of guadipyr was determined in 2 years at three different field sites in China via a dissipation experiment. The half-lives of guadipyr in paddy water were 0.22–0.37 days, 0.24–3.33 days in paddy soil and 0.44–1.90 days in rice plant. The terminal residues of guadipyr ranged from ND (concentrations of guadipyr were below limit of detection) to 50 μg kg?1 in paddy soil, 10–470 μg kg?1 in rice hull, ND70 μg kg?1 in husked rice and ND to 110 μg kg?1 in rice straw. The results would be helpful in fixing maximum residue limit of guadipyr, a new insecticide, in rice. 相似文献
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Xin Wang Shanyi Guan Hongyao Xu Xinyan Su Xuhui Zhu Chun Li 《Journal of polymer science. Part A, Polymer chemistry》2010,48(6):1406-1414
A series of functional polyacetylenes (PAs) bearing diphenyl oxadiazole pendant groups ( P1 – P4 ) were prepared, and the resultant polymers are completely soluble in common organic solvents. Their structures and properties were characterized and evaluated by DSC, TGA, UV, PL, CV, and EL analyses. The results show that all the resulting polymers possesses low LUMO energy level and high thermal stability, and the resultant functional polyacetylenes without spacer group between the polyacetylene conjugated main chain and oxadiazole pendant groups ( P1 – P3 ) show lower LUMO energy level (~?3.87 eV) and higher thermal properties (Tg) than that ( P4 ) with a flexible spacer. The resultant polymer ( P2 ) was applied as an ETM in bilayer electroluminescent devices and effectively enhances external quantum efficiency and the brightness of device, and decreases turn‐on voltages of devices. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1406–1414, 2010 相似文献
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Yew Hoong Leong Sook Fwe Yap Khiok Seng Quek Eng Guan Tay Cherng Luen Tong Yao Teck Ong 《International Journal of Mathematical Education in Science & Technology》2013,44(8):1257-1267
In this article, we share our learning experience as a Lesson Study team. The Research Lesson was on Figural Patterns taught in Year 7. In addition to helping students learn the skills of the topic, we wanted them to develop a problem-solving disposition. The management of these two objectives was a challenge to us. From the lesson observation and the students’ classwork, it turned out better than we expected. 相似文献
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Experimental modal analysis of a tire was carried out. Mode shapes in the radial, tangential and lateral directions of the
tire under radial and tangential excitation, respectively, were obtained for the first time. The consistency of tire experimental
modal frequencies in three directions was observed after careful design and adjustment of the test method. This indicates
the accuracy of the experiments. The phenomena discovered in this experimental study, such as the mode shapes of the rim and
the complex modes of the tire, are discussed in detail. The modal parameters acquired from experimental modal analysis of
the tire can be used for the modeling of tire dynamics. 相似文献