Reversible nonlinear conduction in high‐density polyethylene/acetylene carbon black composites at various ambient temperatures

The reversible nonlinear conduction (RNC) in of high‐density polyethylene/acetylene carbon black composites with different degrees of crosslinking was studied above room temperature and below the melting point of high‐density polyethylene (HDPE). The experimental current density‐electric field strength curves can be overlapped onto a master curve, suggesting that the microscopic mechanisms for the appearance of RNC exist regardless of the ambient temperature and the crosslinking degree of the HDPE matrix. The relationship between the crossover current density and the linear conductivity can be explained in the framework of the dynamic random‐resistor‐network model. According to these results, two electron‐tunneling models are suggested to interpret the microscopic conduction behavior. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1212–1217, 2004     

Synthesis and characterization of polyaniline/graphite conducting nanocomposites

A new method for the synthesis of exfoliated graphite and polyaniline (PANI)/graphite nanocomposites was developed. Exfoliated graphite nanosheets were prepared through the microwave irradiation and sonication of synthesized expandable graphite. The nanocomposites were fabricated via the in situ polymerization of the monomer at the presence of graphite nanosheets. The as-synthesized graphite nanosheets and PANI/graphite nanocomposite materials were characterized with Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and thermogravimetric analysis (TGA). The conductivity of the PANI/graphite nanocomposites was dramatically increased over that of pure PANI. TGA indicated that the incorporation of graphite greatly improved the thermal stability of PANI. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1972–1978, 2004     

A Quantum Chemical Study on Recognition of Nitro-phenols by Calix[n]arenes

A PM3 calculation in vacuum of the inclusion complexation ofo-, m-, p-nitro-phenol with calix[n]arenes is performedsuccessfully. The pathways for inclusion process are describedand the most probable structures of the 1:1 complex are soughtthrough a potential energy scan. The energy differences betweenthe inclusion complexes and the hosts, by calculation, show thatthe most stable complexation is calix[4]-p-nitro phenol andcalix[6]-m-nitro phenol.     

Relationship between the dynamic softening transition and wet sliding friction of elastomer compounds

For properly chosen elastomer compounds, thermorheological characterization is combined with an examination of the variation of the wet sliding friction with temperature. A conceptual argument leads to the assumption that the wet sliding friction should maximize at the energy dissipation peak associated with the dynamic softening transition at a characteristic frequency determined by the sliding speed and the effective smallest surface asperity scale. The dynamic softening transition is characterized with the peak in tan δ/G′ⁿ, where tan δ is the loss tangent, G′ is the elastic modulus, and n is a constant between 0 and 1. The William–Landel–Ferry transform is uncritically applied for extrapolating the position of the peak in tan δ/G′ⁿ at high frequencies. Even based on the criterion of tan δ, the results obtained on a concrete surface indicate that the effective smallest asperity scale is of order of 100 μm. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2467–2478, 2004     

利用声波控制超短脉冲的色散

 声光互作用器件声光可编程色散滤波器（AOPDF）是一种实时的色散补偿器件，它可用于飞秒啁啾脉冲放大系统。通过耦合模理论推导，得到了输出脉冲的群延迟与调制声波的频率、啁啾、带宽等参数的关系，并且对用2.5cm长的LiNbO₃作为声光晶体的AOPDF补偿飞秒光脉冲的色散进行了数值模拟，得到了对中心波长为800 mm的钛宝石飞秒激光色散补偿特性及所需声波的频率和啁啾参数。     

Zn(BTZ)2白色有机电致发光材料的合成及其器件制备

以PCl₃为脱水剂,将邻氨基硫酚与水杨酸脱水环化合成出2-(2-羟基苯基)苯并噻唑,并进一步将所得产物与乙酸锌反应合成出2-(2-羟基苯基)苯并噻唑螯合锌(Zn(BTZ)₂)材料。以该配合物作为发光层制备出结构为ITO/PVK:TPD/Zn(BTZ)₂/Al近白色电致发光器件,其色坐标位于白场之内(x=0.242,y=0.359),在驱动电压为16V时,亮度达3200cdm²,对应的量子效率为0.32%。进一步在Zn(BTZ)₂中掺入橙红色染料Rubrene,制成ITO/PVK:TPD/Zn(BTZ)₂:Rubrene/Al结构器件,实现了纯白色发光(色坐标值:x=0.324,y=0.343),非常接近于白色等能点,且量子效率达0.47%。最后对上述器件的发光和电学性能进行了深入的研究和探讨。     

利用爆磁压缩发生器产生高功率脉冲高电压

 爆磁压缩发生器产生脉冲高电压技术可以用于产生高功率微波及强电磁脉冲的实验研究。给出了利用螺旋型爆磁压缩发生器（HEMG）驱动电爆炸丝功率调节系统产生高功率脉冲高电压的实验方法和主要的结果。在利用HEMG驱动电爆炸丝断路开关（EEOS）产生脉冲高电压实验中，获得了最高电压700~800kV,功率大于20GW的脉冲输出。     

含氮类金刚石薄膜的紫外辐照研究

 用射频等离子体方法在玻璃基底上制备的类金刚石（DLC）薄膜，采用离子注入法掺氮，并对掺氮DLC薄膜紫外（UV）辐照前后的性能变化进行了研究。研究结果表明：随氮离子注入剂量及UV辐照时间的增加，位于2 930cm^-1附近的SP ³C-H吸收峰明显变小，而位于1 580cm^-1附近的SP2C-H吸收峰则明显增强，薄膜的电阻率明显呈下降趋势；随UV辐照时间的增加，位于1 078cm^-1附近的Si-O-Si键数量及位于786cm^-1附近的Si-C键数量明显增加。即氮离子注入和UV辐照明显改变了DLC薄膜的结构与特性。     

Theoretical Study on the Long-lived Complexes for the Na＋I2 Collision System

For the Na I2 collision system, theoretical study is performed on the QCISD(T) level by using ab initio method. The ab initio potential energy surfaces are got and on them the long-lived complexes are found and optimized. These results verify the crossed molecule beam experimental phenomenon and the detailed geometry structures are given for the first time. The role of the complexes in the reaction path is also described in detail.     

Microwave Synthesis, Characterization and DNA-binding Properties of a New Cobalt（ Ⅱ ） Complex with 2,6-Bis（benzimidazol-2-yl）pyridine

A new cobalt(Ⅱ) complex with tridentate ligand 2, 6-bis (benzimidazol-2-yl)pyridine has been synthesized by microwave irradiation method and characterized by elemental analysis,electrochemical and spectral methods. The binding of the complex with calf thymus DNA has also been investigated by absorption and fluorescence spectra.