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31.
32.
在本文中给出了复Grassmann流形上陈氏示性式C_k(Ω)的积分公式如下:  相似文献   
33.
This review summarized the recent advances in small-molecule two-photon fl uorescent probes for monitoring a wide variety of biomolecules and changes inside micro-environment in mitochondria and lysosomes, or served as mitotracker and lysotracker with the assistance of two-photon microscopy.  相似文献   
34.
以石蜡(PA)作为相变储热材料、 膨胀石墨(EG)作为主导热材料和支撑材料, 石墨烯气凝胶(GA)作为导热增强材料和辅支撑材料制备了PA/EG/GA复合相变材料, 研究了GA添加量对复合相变材料相变温度、 相变潜热、 导热性能以及循环稳定性的影响. 结果表明, 所制备的80%PA-17%EG-3%GA复合相变材料导热性能良好, 循环稳定性出色. 与80%PA-20%EG复合材料相比, 该材料的相变温度、 相变潜热以及循环稳定性无明显变化, 但导热系数由4.089 W/(m·K)提升到了5.336 W/(m·K), 显示出良好的应用前景.  相似文献   
35.
胡响明 《光学学报》1995,15(10):1337-1341
采用朗之万激光理论讨论型双模激光近阈运行的模式耦合特性,双模既可以呈相互抑制和相互支持,又可以呈现一模被抑制另一模被支持以及一模或双模既不被支持又不被抑制。耦合特性不仅取决于双模失谐量,而且与原子三能级初始布居紧密相关。  相似文献   
36.
Spherical LiNi1/3Co1/3Mn1/3O2 was successfully prepared by controlled crystallization. The preparation started with the spherical coprecipitate of Ni1/3Co1/3Mn1/3CO3 from NiSO4, CoSO4, MnSO4, NH4HCO3, and NH3·H2O, followed by pyrolysis of Ni1/3Co1/3Mn1/3CO3 at 600°C for 3 h. The X-ray diffraction analysis showed that the homogeneous cubic (Ni1/3Co1/3Mn1/3)3O4 was obtained after the pyrolysis. Spherical LiNi1/3Co1/3Mn1/3O2 was obtained by sintering of the mixture of as-obtained (Ni1/3Co1/3Mn1/3)3O4 and LiOH·H2O at 900°C for 6 h in air. As-prepared spherical LiNi1/3Co1/3Mn1/3O2 presented initial discharge capacity of 162.9 mA h g−1 and capacity retention of 98% at 50th cycle.  相似文献   
37.
Here, we show that 1JNH values are on average 0.4 Hz less negative for double-stranded RNA A:U than for DNA A:T base pairs, which, according to existing theory, suggests that RNA N1...N3 hydrogen bond distances are about 0.02 A shorter than those of DNA. Also, there is a statistically relevant trend between 1JNH and 2hDelta13C2 values, which supports the original hypothesis that 2hDelta13C2 values are also sensitive to hydrogen bond distances. Finally, a context dependence is observed for these values, which suggests that hydrogen-bonding and base-stacking interactions are coupled.  相似文献   
38.
Spherical Sn–carbon core-shell powders (CSCM/Sn) were synthesized through a resorcinol–formaldehyde microemulsion polymerization performed in the presence of SnO2 powders, followed by carbonization in an inert atmosphere. Scanning electron microscope and X-ray diffractometry analyses showed that the Sn powders were thoroughly encapsulated within the carbon microspheres. The CSCM/Sn presented much better cyclability than the conventional Sn–carbon microsphere composite. In core-shell-structured composite, most of the Sn particles were encased inside carbon microspheres and not easy to aggregate or fall off from the microspheres. The carbon shell suppressed the aggregation of tin particles and alleviated the volume change of tin, and the conductive carbon shell effectively decreased the polarization during cycling, giving rise to better high rate performance and excellent capacity retention ability. It is shown that surface structure plays an important role in alloy/C composite anode materials for lithium-ion battery.  相似文献   
39.
本文制备了PS/PC(7/3)和PS/PMMA(5/5)的四氢呋喃(THF)溶液,通过缓慢蒸发溶剂制得PS/PC和PS/PMMA的共混物薄膜。利用不同的FTIR测试方法检测了制得薄膜中的组成分布。将PS/PC薄膜超薄切片,通过显微投射红外方法检测了其纵剖面的组成分布(测试步长为16μm)。结果表明:PS含量从膜底面到表面缓慢增大呈梯度分布,在膜表面附近急剧增大,即PS组分在成膜过程中向表面(与空气  相似文献   
40.
Overcharge performance of LiFePO4 cells is investigated through adding 2, 5-ditertbutyl 1, 4-dimethoxybenzene (DDB) as redox shuttle into electrolyte (RS electrolyte) at different charge rate. RS electrolytes with DDB works well as overcharge protection at low charge rate of less than 0.1 C. Novel charge/discharge characteristics are observed when charge rate increases in the cell with RS electrolyte. Especially, larger discharge capacities are obtained at the same discharge rate after charge rate gets higher than 0.1 C rate. Discharge capacity is larger in the cell with RS electrolyte than that in the cell without RS electrolyte at the same charge and discharge rate. At the same charge rate, cells with RS electrolyte have better cycling performances and larger discharge capacity than that with conventional electrolyte. These indicate that DDB accumulates in cathode with cycling and influences electrode–electrolyte interface reactions.  相似文献   
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