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991.
Three novel conjugated polymers bearing 3,4-bis(4-hexylthiophen-2-yl)-3-cyclobutene-1,2-dione unit in their main chain have been synthesized successfully in good yields through Suzuki or Stille coupling reaction.Their molecular structures have been confirmed by FT-IR,1H NMR and 13C NMR.All these copolymers exhibit broad and strong absorption bands in UV-vis region,and their optical band gaps are calculated to be 1.6-2.0 eV.suggesting that they have good coverage with the solar spectrum.These polymers have good thermostability and solubility in common organic solvents.Moreover,all these objective macromolecules possess high electron affinity of~3.8 eV determined from cyclic voltammetry measurement,implying that they are potential n-type polymeric photovoltaic materials. 相似文献
992.
A novel 4-anilinoquinazoline dimer linked by a carbon-carbon bond in the C-7 position was synthesized via a one step Suzuki cross-coupling reaction. All structures of new compounds were characterized by 1H NMR, 13C NMR, and HRMS. The inhibition rate of the synthetic 4-anilinoquinazoline dimer 8 against epidermal growth factor receptor-tyrosine kinase enzymes (EGFR) in vitro was 44.4% at the concentration of 5.5 μmol/L. 相似文献
993.
Lead nanotapes were synthesized in liquid ammonia solvent in the presence of sodium metal at low temperature.The process was template free.Transmission electron microscopy(TEM) observations and X-ray diffraction(XRD) characterizations revealed that the as-prepared Pb nanotapes have average diameters in the range of 40-50 nm.and lengths up to several hundred nanometers, and exhibit cubic crystal structures. 相似文献
994.
Jian Hong Yang Jian Xin Pu Xue Du Hai Bo Zhang Wei Lie Xiao Han Dong Sun 《中国化学快报》2011,22(9):1078-1080
Two new compounds,corialins A(1) and B(2) were isolated from Coriaria nepalensis Wall.These new compounds were established as 7-hydroxy-3-[2,3-acetonide-(3-methylbutane)]coumarin(1) and 3-O-β-D-glucopyranosyl-3,4,5-trihydroxy-1-(3- methyl-2-butenyl)-benzene(2),on the basis of 1D and 2D NMR techniques. 相似文献
995.
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998.
在还原气氛下高温固相法合成了CaAl12O19:Eu2+,Cr3+荧光粉.样品光谱显示:Eu2+发射带与Cr3+吸收带有重叠,具备Eu2+-Cr3+之间发生能量传递必要条件.在290 nm近紫外光激发下,单掺杂Eu2+和Cr3+时样品均无691 nm发射,仅在Eu2+,Cr3+共掺时才出现691 nm发射,这证明Eu2+和Cr3+之间发生了能量传递,且监测691 nm时样品的激发光谱也证实了这一点.CaAl12O19:1%Eu2+,x%Cr3+样品组的发射光谱研究表明:增大x能提高Cr3+红光与Eu2+蓝紫光发射强度之比及Eu2+-Cr3+之间能量传递效率.CaAl12O19:2%Cr3+,x%Eu2+样品组的激发光谱分析表明:x>2时,Cr3+在415 nm处的吸收效率相对于565 nm有显著提高.还对样品CaAl12O19:1%Eu2+,1%Cr3+荧光寿命和能量传递速率进行了简单分析. 相似文献
999.
液相色谱-串联质谱法检测动物源性食品中激素残留所遇到问题的探讨 总被引:1,自引:0,他引:1
探讨了液相色谱-串联质谱法用于动物源性食品中激素残留检测时关于样品的提取与净化、酶解、基质效应和激素来源等问题(引用文献29篇)。 相似文献
1000.
Selective hydrogenation of benzene to cyclohexene on Ru-basecatalysts promoted with Mn and Zn 下载免费PDF全文
Ru-based catalysts promoted with Mn and Zn were prepared by a co-precipitation method. In liquid-phase hydrogenation of benzene, the Ru-Mn-Zn catalysts exhibited superior catalytic performance to the catalysts promoted with Zn or Mn alone. The optimum Mn/Zn molar ratio was determined to be 0.3. With the addition of 0.5 g NaOH, the Ru-Mn-Zn-0.3 catalyst, which was reduced at 150 ? C, afforded a cyclohexene selectivity of 81.1% at a benzene conversion of 60.2% at 5 min and a maximum cyclohexene yield of 59.9% at 20 min. Based on characterizations, the excellent performance of Ru-Mn-Zn catalyst was ascribed to the suitable pore structure, the appropriate reducibility and the homogenous chemical environment of the catalyst. 相似文献