场致发射体的局域功函数研究

实际场致发射体表面不可能绝对光滑 ,而具有原子尺度的微小凸起会导致发射电流大大增加。基于发射电流主要来自于原子尺度微小凸起的假设 ,提出了局域半球镜像电荷模型 ,研究了场致发射功函数的降低 ,发现微小凸起处场致发射的局域功函数会降低而场增强因子将增大。将它代入F N公式计算了一个典型的单尖Spindt阴极的发射电流 ,所得结果与实验符合。在只考虑Nottingham效应的情况下 ,计算了一些材料Spindt型阴极每微尖的最大稳定发射电流     

场致发射体的局域功函数研究

实际场致发射体表面不可能绝对光滑,而具有原子尺度的微小凸起会导致发射电流大大增加。基于发射电流主要来自于原子尺度微小凸起的假设,提出了局域半球镜像电荷模型,研究了场致发射功函数的降低,发现微小凸起处场致发射的局域功函数会降低而场增强因子将增大。将它代入Ｆ－Ｎ公式计算了一个典型的单尖Ｓｐｉｎｄｔ阴极的发射电流,所得结果与实验符合。在只考虑Ｎｏｔｔｉｎｇｈａｍ效应的情况下,计算了一些材料Ｓｐｉｎｄｔ型     

金刚石薄膜阴极电子发射特性研究

宽带隙半导体材料金刚石的负电子亲合势特性使其在电子场发射应用方面备受瞩目。材料的功函数对其热电子发射或场电子发射都有决定性的影响，本从热电子发射的角度出发，对钨基金刚石薄膜阴极有效功函数进行了测量，章阐述了实验方法，装置及结果，测得金刚石涂层阴极的有效功函数为０．７０ｅＶ，并对实验结果进行了理论分析。     

金刚石薄膜阴极电子发射特性研究

宽带隙半导体材料金刚石的负电子亲合势特性使其在电子场发射应用方面备受瞩目。材料的功函数对其热电子发射或场电子发射都有决定性的影响。本文从热电子发射的角度出发 ,对钨基金刚石薄膜阴极有效功函数进行了测量。文章阐述了实验方法、装置及结果 ,测得金刚石涂层阴极的有效功函数为 0 70eV ,并对实验结果进行了理论分析     

长链羧酸单分子层膜的制备和性能

首次在涂敷PEI的玻璃表面上制备了癸酸及全氟癸酸的单分子层膜，研究了成膜机理及摩擦特性，结果表明，脱水剂DCCD促进了癸酸或全氟癸酸与PEI酰胺化的反应，导致两种羧酸在PEI表面产生了靠化学键（酰胺键）连接的稳定的单分子层膜，摩擦，摩损实验表明，单分子层有机膜的摩擦特性受膜的组成，表面能及有序性和堆积密度的重要影响，表明能越低，有序性和堆积密度越高，摩擦系数越低，与碳氢化合物相比，碳氟化合物形成的有序膜具有更高的强度和抗磨性能。     

利用大气中放电来测量表面特性的新方法

研制了一种新型的探测器，利用气体放电和外部电路猝灭的方法测定样品表面发射的低能光电子。它能在大气或各种气氛中工作。可用于测定表面功函数、膜厚、表面污染及材料缺陷。有较大实用价值。     

新型两亲性铕配合物LB膜的性质研究

研究了一种新型带有长烷基链的铕配合物Langmuir-Blodgett（LB）膜及其发光性质。实验结果表明，此种配合物能够在水面上形成稳定的单分子膜，单分子占有面积为0．6nm^2，并可将单分子Langmuir膜沉积在亲水的石英基片上，其紫外结果表明，位于287nm处的主吸收峰随着LB膜层数的增加而增加，其吸收强度随层数的增加呈线性关系，证明可以形成均匀LB膜。对其LB膜的荧光光谱研究结果显示，具有典型的铕配合物的发射峰，且具有一定的荧光强度。这为以铕配合物作为分子器件的材料研究提供了实验基础。     

钨带灯的稳定性判据试验

我们通过对国产ＢＷ—１４００型真空钨带灯的稳定性判据进行研究，发现通过钨带灯的电流达到稳定的时间很短（小于５分钟），而钨带灯的灯电阻需要经过２０分钟后才能达到稳定，因此，用电流稳定性作为钨带灯的热平衡判据是不够的，更可靠的判据还应看灯电阻是否达到平衡。     

高压高温合成复合氧化物半导体纳米块体材料的结构和电学性质

采用高压高温合成方法制备出锰镍复合氧化物半导体纳米块体材料。用X射线衍射（XRD），高分辨电子显微镜（HTEM）表征纳米块体材料的结构。用恒压源测定室温下电流－电压曲线（零功率）。实验结果表明：纳米固体材料微观结构存在长程有序的晶粒结构与界面无序态的结构。纳米固体材料的电学特性与材料的微观结构有关。     

爆破作用下含后缘裂隙岩质边坡的断裂力学分析

为探究爆破荷载作用下含后缘裂隙岩质边坡失稳机制,利用断裂力学相关理论,推导了爆破作用下岩质边坡后缘裂隙尖端复合应力强度因子计算公式,将裂隙尖端应力强度因子与边坡岩体的断裂韧度的比值定义为边坡稳定性系数,分析了结构面几何参数和爆破参数对边坡稳定性的影响和裂隙扩展方向的变化规律,最后通过现场实例进行验证。研究结果表明：爆破荷载的作用,改变了裂隙尖端应力场的分布情况,增加了裂隙尖端复合应力强度因子,降低了边坡稳定性系数。后缘裂隙角度越大、裂隙越长、频率越大、和平均高度越小,边坡越不稳定。采用断裂力学法对边坡稳定性的预测更加安全可靠,且能准确计算出裂隙起裂角的大小和方向,裂隙长度对裂隙起裂角无影响。     

多晶金刚石锥状场发射阵列冷阴极研究

本文报导了一种新型金刚石场发射阵列冷阴极的制造方法和电子发射性能，通过数据分析得到了这种金刚石发射体的有效表面功函数和总有效发射面积。并与用其它方法获得的几种膜的发射性能作了比较。测量结果表明，这是一种很有应用潜力的制造方法。     

Preparation and field-emission of TaSe2 nanobelt quasi-arrays, and electrical transport of its individual nanobelt

3R-TaSe2 nanobelt quasi-arrays were gown on a Ta foil by a facile two-step method, namely, firstly the TaSe3 nanobelt arrays were grown on a Ta foil by a surface-assisted chemical vapor transport, and then they were pyrolyzed to 3R-TaSe2 nanobelt quasi-arrays in vacuum. The nanobelts have low work function and the Ta foil has high conductivity, so the nanobelt arrays possess good electronic field emission performance with a low turn-on (3.6 V/microm) and threshold fields (4.3 V/microm) (which are defined as the macroscopic field required to produce a current density of 10 microA/cm2 and 1 mA/cm2, respectively) and a high enhancement factor (1045) at an emission distance of 200 microm. The electric transport of the individual nanobelt reveals that it is a high-conductive semiconductor, and observed by the variable-range hopping model. It suggests that the nanobelts have potential applications in field emission and field effect transistors.     

用于平面显示的MISM结构阴极

讨论了平面型场致热化电子发射阴极,对玻璃衬底/Mo/Ta2O5/ZnS/Au结构的平面型场致热化电子发射阴极的制备及其发射性能进行了论述,讨论了在不同工艺参数下器件的发射情况。实验表明,通过优化溅射时间参数和工艺手段制成的阴极对发射电流的大小有很大影响。通过对这些工艺参数的调整,得到了最高发射比(Ia/Ig)为4.5×10-4,向该阴极实用化迈进了一步。     

The Influence of Cs Adsorption on Field Electron Emission from Single-Walled Carbon Nanotube Layers

The influence of Cs adsorption on field emission characteristics of single-walled carbon nanotube (SWNT) layers has been investigated. It has been found that Cs adsorption onto SWNT tips not only decreases the work function of SWNTs with the corresponding increase of the emission current, but also causes the additional increasing of the emission current in tens times without the decrease of the work function. We attribute the second effect to the appearance of local surface states associated with Cs, that increase the transparency of the surface potential barrier.     

缺位型强电流铁电阴极材料的研究

采用一种新型的缺位型铁电陶瓷作为阴极材料 ,获得了 1 87A/cm2 的强电流发射密度。通过缺位型与非缺位型材料的发射电流的对比 ,从理论上分析了缺位对于电子发射的影响 ,从材料学角度出发 ,总结出提高发射电流密度的三种有效方法 :即增强阴极表面半导体性 ,增大内偏置电场和增大材料的介电常数     

Fabrication of multi-emitter array of CNT for enhancement of current density

We studied and compared field emission properties of two kinds of emitters of randomly oriented multi-wall carbon nanotubes (MWNTs), viz. continuous film emitter (CFE) and multi-emitter array (MEA). The CFE has a continuous film of MWNTs while the MEA consists of many equidistant small circular emitters. Both types of emitters were prepared by dispersing MWNTs over a titanium (Ti) film (for CFEs) or Ti circular islands (for MEAs) deposited on tantalum (Ta) followed by rooting of MWNTs into the Ti film or the Ti islands at high temperature. Emission properties of both types of emitters were analyzed with changing their emission areas. In case of the CFEs, current density decreased with an increase in emission area whereas consistent current densities were achieved from MEAs with different emission areas. In other words, the total emission current was achieved in proportion to the emission area in the case of MEAs. Additionally a high current density of 22 A/cm² was achieved at an electric field of 8 V/μm from MEAs, which was far better than that obtained from CFEs. The high current density in MEAs was attributed to edge effect, in which higher emission current is achieved from the edge of film emitter. The results indicate that the field emission characteristics can be greatly improved if a cathode contains many small equidistant circular emitters instead of a continuous film. The outstanding stability of the CFE and the MEA has been demonstrated for 2100 and 1007 h, respectively.     

Selffield losses and selffield stability of superconducting wires with low conductivity matrix material

The influence of the normal material in a superconducting wire on the selffield losses has been investigated. The results show that the contribution of the normal material is considerable in the case of a highly conductive material like Cu. Measurements on wires with CuNi-material show no significant contribution of the normal material to the losses. In the latter case, however, special attention should be paid to stability. Measurements show that the obtainable maximum current under a.c. conditions obeys the adiabatic stability criterion rather well. The dependence of the maximum current amplitude on the critical current density and the diameter of the wire has been obtained. Wires with Al cores inside the NbTi filaments for better stabilization have also been investigated regarding maximum current and selffield losses.     

超高真空下小型四极质谱计的性能研究

在超高真空下对QMS200小型四极质谱计进行了实验研究。实验通过调节离子源的发射电流、聚焦电压和场轴电压,测量了质谱计灵敏度、线性以及图样系数的相应变化。实验结果表明,不同的参数设置对质谱计性能有不同的影响。文章结论对四极质谱计应用具有一定的参考价值。