丁磺酸内酯对锂离子电池性能及负极界面的影响

用循环伏安(CV)、电化学阻抗谱(EIS)、扫描电镜(SEM)、能谱分析(EDS)及理论计算等方法研究了添加剂丁磺酸内酯(BS)对锂离子电池负极界面性质的影响. 研究表明, 在初次循环过程中, BS具有较低的最低空轨道能量, 优先于溶剂在石墨电极上还原分解, 并形成固体电解质相界面膜(SEI膜). 在含BS的电解液中形成的SEI膜的热稳定性高, 在70 ℃下储存24 h后, 膜电阻和电荷迁移电阻大小基本保持不变, 而在不含BS的电解液中形成的SEI膜的热稳定性较差, 在70 ℃下储存24 h后, 膜电阻和电荷迁移电阻大小有明显的增加. 从BS对锂离子电池电化学性能影响的研究表明, 加入少量的BS能够显著提高锂离子电池的室温放电容量、低温及高温储存放电性能.     

Dynamics of superionic Rb3H(SeO4)2 single crystals studied by H and Rb spin-lattice relaxation

The ¹H and ⁸⁷Rb spin-lattice relaxation and spin-spin relaxation times in superionic Rb₃H(SeO₄)₂ single crystals grown by the slow evaporation method were measured over the temperature range 160-450 K. The temperature dependencies of the ¹H T₁, T_1ρ, and T₂ are measured. In the ferroelastic phase, T₁ differs from T_1ρ, which is in turn different from T₂, although these three relaxation times converge to similar values near 410 K. This transition seems to occur at temperature which is about 40 K lower than the superionic transition temperature. The observation of liquid-like values of the ¹H T₁, T_1ρ, and T₂ in the high temperature is compatible with the phase being superionic, indicating that the destruction and reconstruction of hydrogen bonds does indeed occur at high temperature. In addition, the ⁸⁷Rb T₁ and T₂ values at high temperature were similar (on the order of milliseconds), a trend that was also observed for ¹H T₁ and T₂. This behavior is expected for most hopping-type ionic conductors, and could be attributed to interactions between the mobile ions and the neighboring group ions within the crystal. The motion giving rise to this liquid-like behavior is related to the superionic motion.     

4-苯乙炔基苯胺封端聚酰亚胺树脂的合成与性能研究

使用4-苯乙炔基苯胺(4-PEA)作为反应性封端剂,和3,3′,4,4′-二苯醚四酸二酐(ODPA),3,3′,4,4′-联苯四酸二酐(BPDA),1,4-双(4′-氨基-2′-三氟甲基苯氧基)苯(BTPB)和3,4′-二氨基二苯醚(3,4-′ODA)反应合成了系列4-苯乙炔基苯基封端的聚酰亚胺低聚物,对低聚物的化学结构、热性能和熔体粘度以及固化后树脂的热性能等进行了研究.实验结果表明,低聚物均具有一定的结晶性,含有ODPA的聚酰亚胺低聚物较之含有BPDA的低聚物具有更低的熔体粘度,且出现最低熔体粘度的温度更低;固化后的树脂表现出良好的热性能,含有BPDA的树脂具有更高的玻璃化转变温度;系列低聚物中二胺单体的比例对于低聚物的熔体粘度和固化后树脂的热稳定性有一定影响.     

Recent progress and challenges in carboxylation with CO2

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树脂填充EVAL纤维吸附剂的制备及其吸附性能表征

采用具有亲水性的乙烯-乙烯醇共聚物(EVAL)作为纤维吸附剂基质材料,粉末型Lewatit阳离子交换树脂CNP80ws为功能材料,采用可控相分离方法,制备了不同表面形态结构的树脂填充EVAL吸附剂.当使用外部液体调控相分离过程时,在纤维的表面形成了粗糙的开孔结构,并且随树脂的填充量提高纤维表面的粗糙度与开孔度有所提高.研究结果表明:树脂填充EVAL纤维吸附剂具有较大的吸附容量与较高的脱附率,其吸附容量不低于53.9mg BSA/g吸附剂(树脂填充量50%).     

(Y,Gd)VO_4∶Eu~(3+)的紫外-真空紫外发光特性

用高温固相法合成了Y1-xGdxVO4∶Eu3 (0≤x≤1)系列单相样品并研究了其发光特性。在254nm激发下,观察到最大强度位于619nm的红色发射峰且其强度在Y/Gd=0.4/0.6时达到最大。在147nm激发下的发射峰与紫外下的一致,发射强度也是在Y/Gd=0.4/0.6时达到最大,大约是商用(Y,Gd)BO3∶Eu3 荧光体的65%。619nm监控下的真空紫外激发光谱由峰值位于158nm,204nm,247nm以及300nm的系列激发带组成,归属于钒酸根的基质吸收以及Gd3 、Y3 和Eu3 的电荷迁移带吸收。相对(Y,Gd)BO3∶Eu3 中Eu3 占据中心对称格位,(Y,Gd)VO4∶Eu3 中Eu3 占据非中心对称格位,其真空紫外下光谱色纯度更好。色坐标分别为(0.632,0.355),(0.672,0.328)。     

Experimental and density functional studies on two structurally similar antipyrine derivatives: 4-(2-hydroxy-5-nitrobenzylidene-amino)-1,2-dihydro-1,5-dimethyl-2-phenylpyrazol-3-one and 4-(3-bromo-5-chloro-2-hydroxybenzylideneamino)-1,2-dihydro-1,5-dimethyl-2-phenylpyrazol-3-one

The Schiff base compounds, 4-(2-hydroxy-5-nitr- obenzylideneamino)-1,2-dihydro-1,5-dimethyl-2-phenylpy- razol-3-one and 4-(3-bromo-5-chloro-2-hydroxybenz- ylideneamino)-1,2-dihydro-1,5-dimethyl-2-phenylpyrazol-3-one, have been synthesized and characterized by elemental analysis, IR, and X-ray single crystal determination. Density functional calculations of the structures, natural bond orbitals, and frontier molecular orbitals and Mülliken charge analysis on the compounds were performed at B3LYP/6-31+G(d) level of theory. Vibrational frequencies were also predicted, assigned, and compared with the experimental values, which supported each other.     

紫外预电离TEA CO2激光器放电特性的实验研究

 横向激励大气压（transversely excited atmospheric,TEA）CO₂激光器的放电稳定性是决定该类型激光器应用效果的关键因素。通过对采用电感充放电电路的紫外预电离激光器的实验研究，得到了激光器放电动态过程的规律，并发现残余振荡是主放电后发生弧光放电的主要原因。实验中采用不同配比的气体，并对电感充放电电路与改进后的硅堆充放电电路进行了比较。实验结果表明：增加充电电感值可以降低主放电结束后储能电容上的残余电压；而采用硅堆放电电路在主放电后仅有相对幅值很低的稳定残压，两种方案都大幅度抑制了弧光放电的形成，有效地提高了激光单脉冲能量。     

647W灯泵浦大功率连续Nd:YAG激光器

 报道了一台灯泵浦大功率连续Nd:YAG激光器。对影响大功率固体激光器模块输出功率和光束质量的主要因素进行了理论分析，并提出提高激光器效率的措施：对聚光腔的形状、结构和材料以及冷却方式，泵浦灯的参数和材料，激光晶体的参数和镀膜进行优化设计，采用径向固定的谐振腔镜。该灯泵浦YAG晶体棒总体电光转换效率为4%，光束质量为22mm·mrad，输出功率647W。