CF_3I分子在外电场中的物理和光谱性质研究

CF_3I是公认的用以代替SF6的新型环保绝缘气体,其在外电场中的具体性质的研究至关重要.利用密度泛函理论(DFT),在B3LYP/DGDZVP基组水平上,从分子结构角度研究了CF_3I气体在外电场(-0. 02 a. u.～0. 02 a. u.)作用下的光谱特征和解离特性.计算结果表明,沿C至I方向的电场增强时:C-I键键长单调增大,能隙E_g单调减小;分子总能量先增大后减小,偶极矩先减小后增大;费米能级EF单调减小,但当电场增至C至I方向0. 010 a. u.时,费米能级EF出现局部极大值.外电场对分子红外光谱的影响表现为:沿C至I方向电场强度增大时,四个振动频率红移(包括最高峰),其余两个蓝移.分子的解离特性表现为:沿C至I方向强度超过0. 025 a. u.的电场可使C-I键断裂.以上结果为CF_3I或其与其混合物在外电场下的特性研究提供了参考.     

改性CF与EVA复合材料的PTC行为研究

试图通过增强EVA与CF之间的相互作用来消除NTC现象. 由于CF表面光滑, 惰性大, 将CF用KMnO4表面氧化后与具有活性官能团的EVA熔融共混, 得到EVA-改性CF复合物.     

Study on the Tribological Properties of Carbon Fabric/Polyimide Composites Filled with SiC Nanoparticles

Carbon fabric reinforced thermoplastic polyimide composites have significant applications in the field of tribology. However, there are relatively few studies that have been focused on the investigation of these materials. In the present study, carbon fabric/polyimide (CF/PI) composites, reinforced further with SiC nanoparticles, were prepared by dip-coating and hot press molding methods. Rockwell hardness and flexural testing of the composites were conducted. The friction and wear behavior of the resulting carbon fabric composites were evaluated in a ring-on-block contact mode under dry sliding condition. The results showed that the SiC nanoparticles significantly improved the hardness and flexural strength when compared to the CF/PI composites without the SiC additions. The CF/PI composites reinforced with 5 vol% SiC nanoparticles demonstrated the most beneficial mechanical and tribological properties compared to the composites with greater and lesser SiC nanoparticles. Scanning electron microscopy (SEM) and optical microscopy (OM) were employed in order to study the mechanism of tribological behavior. A continuous and thin transfer film formed during the friction test of the composites led to a significant improvement of the tribological properties.     

晶体(ZnKPO_4·6H_2O)∶VO~(2+)的自旋哈密顿参数及局域结构

基于晶体场理论和电荷转移机制,采用双旋-轨耦合参量模型的3d~1离子在D_(4h)对称的晶场中自旋哈密顿参量的高阶微扰公式和晶场能级公式,计算了(ZnKPO_4·6H_2O)∶VO~(2+)晶体的光吸收谱和自旋哈密顿参量。本文不仅考虑了晶场机制,同时也考虑了电荷转移机制。计算结果与实验数据是一致的。说明电荷转移机制对(ZnKPO_4·6H_2O)∶VO~(2+)晶体的自旋哈密顿参量的结果有不可忽略的作用。     

用Raman光谱研究碳纤维/聚醚醚酮复合材料的界面结构

用Ｒａｍａｎ光谱研究碳纤维／聚醚醚酮复合材料的界面结构李铁骑章明秋曾汉民（中山大学材料科学研究所聚合物复合材料及功能材料国家教委开放研究实验室广州５１０２７５）关键词界面结构，Ｒａｍａｎ光谱，碳纤维／聚醚醚酮复合材料随着近年来热塑性聚合物的加工...     

聚对苯二甲酸乙二酯膜的表面碳氟等离子体改性及XPS取样深度与接触角间的关系

高聚物界面的能量、结构等性质，对理论研究和实际应用都是极为重要的．因为许多聚合物材料都具有一个或多个界面的多相结构，这些界面的结构和强度等，显著地影响着这些多相材料的物理、力学性能等，而它们之间的关系，是一个极为复杂的问题，只有综合界面科学、流变学、...     

Synthesis and langmuir isotherms of difluorostearic acids

The CF₂ containing 6,6- and 10,10-difluorooctadecanoic acids 7 and 8, respectively have been synthesised and their Langmuir isotherms evaluated. In marked contrast to the behaviour of octadecanoic acid (stearic acid) 1 it is demonstrated that spreading on an aqueous subphase generates an unstable monolayer which reorganises to a more stable bilayer structure. Grazing incidence X-ray scattering and ellipsometric measurements after deposition of 8 from the subphase onto a silicon wafer, confirmed a bilayer structure. These observations reinforce our earlier conclusions with 12,12-difluorooctadecanoic acid that substitution of CH₂ by CF₂ leads to increased conformational flexibility of a hydrocarbon chain.     

CF自由基5pπE2Пr(ν’=1)←X2П(ν’’=0)带的转动分析

The two-photon resonance-enhanced multiphoton ionization spectrum between 285 and 288.5 nm of the 5pπE2Πr(v’=1)←X2Πr(v’’=0) band of CF radical is reported. The band is rotationally analyzed, and the spectroscopic constants of the state are first derived: σ0 = 69566.38±0.52 cm-1, A'v= 46.4±0.3 cm-1, B'v= 2.565±0.017 cm-1, D' v = (8.6±1.2)×10-6cm-1.     

O（~1D）与CF_2HCl反应的理论研究

用量子化学密度泛函理论（DFT）和G3B3方法，对为（~1D）与CF_2HCl的反应 进行了研究，在B3LYP/6-311+G(d)，B3LYP/6-311+G(2df,2pd)和G3B3计算水平上， 优化了反应热能面上各驻点的几何结构，通过内禀反应坐标（IRC）计算和振动分 析，对反应过渡态进行了确认，并确定了反应机理。