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1.
对德国康斯坦茨大学的本科有机化学实验初级阶段和高级阶段的教学方式,从实验前准备、实验内容、实验教学模式、实验考核方式、实验室安全管理等方面进行了综合阐述,可为我国高校相关专业有机化学实验教学与改革提供参考,提高教学质量。 相似文献
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以碳纤维(CF)为填料,聚偏氟乙烯(PVDF)为基体,通过熔融共混法制备PVDF/CF导电复合材料.所得复合材料具有显著的正温度系数(PTC)效应,温度上升到聚合物熔点附近时,电阻率对温度变化敏感.在转折温度区间(155.5~171.0oC,(35)(28)15.5oC)内,其体积电阻率的增加速率约为1.3×105?cm K-1.在不同CF含量下,复合材料表现出不同的PTC行为.随着CF含量的增加,其峰值电阻略有下降.高导电粒子含量下,无负温度系数(NTC)效应.在冷却循环过程,导电网络的重构性良好.复合材料即使经过多次热循环,依然表现出良好的PTC特性重现性. 相似文献
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Tuning hybrid liquid/solid electrolytes by lowering Li salt concentration for lithium batteries 下载免费PDF全文
Hybrid liquid/solid electrolytes(HLSEs) consisting of conventional organic liquid electrolyte(LE), polyacrylonitrile(PAN), and ceramic lithium ion conductor Li_(1.5)Al_(0.5)Ge_(1.5)(PO_4)_3(LAGP) are proposed and investigated. The HLSE has a high ionic conductivity of over 2.25 × 10~(-3) S/cm at 25?C, and an extended electrochemical window of up to 4.8 V versus Li/Li+. The Li|HLSE|Li symmetric cells and Li|HLSE|Li FePO_4 cells exhibit small interfacial area specific resistances(ASRs) comparable to that of LE while much smaller than that of ceramic LAGP electrolyte, and excellent performance at room temperature. Bis(trifluoromethane sulfonimide) salt in HLSE significantly affects the properties and electrochemical behaviors. Side reactions can be effectively suppressed by lowering the concentration of Li salt. It is a feasible strategy for pursuing the high energy density batteries with higher safety. 相似文献
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针对氧乐果合成过程中温度控制具有参数时变、时滞后、非线性的特点,提出了一种基于改进粒子群算法的支持向量回归的建模方法。对于支持向量回归模型,3个参数(ε,C,γ)的选取很大程度上决定了其拟合的精度和泛化能力的好坏,采用改进的粒子群算法对参数(ε,C,γ)进行同时寻优,建立了改进的氧乐果合成过程PSO-SVR回归模型,该模型具有很好的学习能力和推广能力。实验结果表明,模型较好地体现了系统的动态特性,可用于氧乐果合成过程的模型预估控制,提高系统的控制品质。 相似文献
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以正硅酸乙酯(TEOS)和六甲基二硅氮烷(HMDS)为前驱体,研究了引入聚乙烯吡咯烷酮(PVP)对膜层的影响,在碱催化条件下制备了改性的二氧化硅溶胶,并采用提拉涂膜的方法在石英基底上涂膜。对不同组分的薄膜,先经热处理或紫外辐照处理,然后用十八烷基三氯硅烷(OTS)/甲苯溶液对膜层表面进行化学修饰,制备出疏水性能良好的纳米二氧化硅自组装薄膜,分析了不同后处理方法对膜层透过率、接触角、膜层表面微观形貌和激光损伤阈值影响。实验结果表明:溶胶中加入PVP提高了膜层的平整度,经OTS改性后膜层疏水性和激光损伤阈值均得到提高。 相似文献
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Highly efficient polymer phosphorescent light-emitting devices based on a new polyfluorene derivative as host 下载免费PDF全文
Several highly efficient iridium-complex polymer light-emitting devices (PLEDs) are fabricated,with a newly synthesized blue conjugated polymer,poly[(9,9-bis(4-(2-ethylhexyloxy)phenyl)-fluorene)-co-(3,7-dibenziothiene-S,S-dioxide15)] (PPF-3,7SO15),chosen as host.High luminous efficiencies of 7.4 cd·A 1 and 27.4 cd·A 1 are achieved in red and green PLEDs,respectively,by optimizing the doping concentrations of red phosphorescent dye iridium bis(1-phenylisoquinoline) (acetylacetonate) (Ir(piq)) and green phosphorescent dye iridium tris(2-(4-tolyl)pyridinato-N,C 2) (Ir(mppy) 3).Furthermore,highly efficient white PLEDs (WPLEDs) with the Commission Internationale de l’Eclairage (CIE) coordinates of (0.35,0.38) are successfully produced by carefully controlling the doping concentration of the irid-ium complex.The obtained WPLEDs show maximal efficiencies of 14.4 cd·A 1 and 10.1 lm·W 1,which are comparable to those of incandescent bulbs.Moreover,the electroluminescent spectrum of the white device with an initial luminance of about 1000 cd·m 2 is stable,subject to constant applied current stress,indicating that good device stability can be obtained in this system. 相似文献
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The full aperture complex amplitude transmittance function of a multi-level diffraction lens with maskalignment errors was derived based on scalar diffraction theory. The point spread function(PSF) was calculated by the Kirchhoff diffraction integral. It is found that the radius of the Airy disk increases with the increase of the error in the direction of misalignment, and the image center shifts along the direction of misalignment. A fourlevel diffractive lens with a diameter of 80 mm was fabricated, and its PSF and diffraction efficiency of +1 st order were calculated and measured. The distribution of PSF is consistent with the calculated results, and the tested diffraction efficiency is slightly smaller than the calculated value; the relative error is 5.71%. 相似文献