在惯性系中求解落体偏东问题

在惯性系中从机械能守恒出发求解了落体偏东问题并计算了下落过程中质点的引力势能与动能的转化.     

ZnO纳米管的拉曼光谱学研究

通过对ZnO纳米管样品的拉曼光谱研究,发现ZnO纳米管拉曼频率和体材料拉曼频率相同,在不同波长激发下,ZnO纳米管拉曼谱峰的频率也保持不变,从而得到了极性晶体拉曼谱不同于以往非极性拉曼谱的特性:在纳米体系中没有出现明显的尺寸限制效应。     

Investigation of the growth process of Si nanowires using the vapour－liquid－solid mechanism

Silicon nanowires have been grown by the thermal decomposition of silane via the vapour－liquid－solid (VLS) mechanism. Three different stages of VLS growth (eutectic alloy formation, crystal nucleation and unidirectional growth) were studied separately using a scanning electron microscope and a high-resolution transmission electron microscope. Very short silicon nanowires prepared under particular conditions provide direct evidence of the VLS mechanism on a nanometre scale. Our results will be very helpful for the controllable synthesis of Si nanowires.     

Increased work function in PEDOT:PSS film under ultraviolet irradiation

An increase of work function （0.3 eV） is achieved by irradiating poly（3,4-ethylenedioxythiophene）：poly（styrene sul- fonate） （PEDOT：PSS） film in vacuum with 254-nm ultraviolet （UV） light. The mechanism for such an improvement is investigated by photoelectron yield spectroscopy, X-ray photo electron energy spectrum, and field emission technique. Sur- face oxidation and composition change are found as the reasons for work function increase. The UV-treated PEDOT：PSS film is used as the hole injection layer in a hole-only device. Hole injection is improved by UV-treated PEDOT：PSS film without baring the enlargement of film resistance. Our result demonstrates that UV treatment is more suitable for modifying the injection barrier than UV ozone exposure.     

Curbing Charging Currents in Pulsed Field Emission by Prolonging Pulse Edges

In field emission under a non-dc voltage, a displacement current is inevitable due to charging the cathode–anode condenser. Under an often-used square voltage pulse, in which the voltage rises from zero to a certain value abruptly, the charging current in the circuit is very large at the rising and falling edges. This large charging current makes measurement of the actual emissive current from the cathode difficult, constitutes a threat to the components in the circuit and causes attenuation of the emissive current within the pulse. To alleviate these drawbacks, trapezoid voltage pulses, whose rising edges are extended dramatically in comparison with square voltage pulses, are employed to extract the field emission. Under a trapezoid voltage pulse, the charging current is clearly lowered as expected. Furthermore, the heat generated by the charging current under the trapezoid voltage pulse is much smaller than that under the square voltage pulse. Hence the emissive current does not show any attenuation within the pulse. Finally, the average emissive currents are found to decrease with the repetition frequency of the pulses.     

用全息错位干涉计量术判别物体变形方向

本文给出了一种在双曝光全息干涉计量术中判别变形方向的方法.该方法需在双曝光期间移动全息干板,因而可将其视为一种位错全息干涉术.文中还给出了实验验证.     

Growth of Silicon Nanowires by Heating Si substrate

Amorphous silicon nanowires were prepared by heating an Si substrate at high temperatures using an Ni (or Au) catalyst.The nanowires have a diameter of 10-40nm and a length of up to several tens of micrometres.Unlike the well-known vapour-liquid-solid mechanism,a solid-liquid-solid mechanism appeared to control the nanowire growth.The heating process had a strong influence on the growth of silicon nanowires.It was found that ambient gas was necessary to grow nanowires.This method can be used to prepare other kinds of nanowires.