SiO_2/CH/Au复合黑腔诊断孔电火花加工技术

通过电火花加工技术,采用含碳较高的煤油作为电介质,利用导电性能及加工性能较好的紫铜作电极材料,实现了SiO2/CH/Au复合黑腔侧表面方形诊断孔的精密加工。采用OLYMPUS STM6测量显微镜对诊断孔尺寸,结果表明:孔的尺寸加工精度可控制在±10μm内,同一电极加工的诊断孔尺寸一致性可控制在±5μm内。采用扫描电镜能谱分析SiO2/CH/Au加工导电层的成分,结果表明:电火花加工过程中,由于电介质分解生成游离态的碳以及电极材料铜熔融后沉积在CH和SiO2层表面,形成辅助导电层。通过加工辅助导电层,产生的瞬时高温使SiO2和CH层熔融气化,从而实现对绝缘层的加工。     

黑腔芯轴平台微细电火花加工技术

采用电火花成型加工技术,在黑腔芯轴侧表面加工平台。采用白光干涉仪对平台表面轮廓及粗糙度测量,结果表明:平面部分表面粗糙度小于0.5μm,最大峰谷高度小于15μm。通过奥林巴斯测力显微镜对平台尺寸测量,结果表明:平台的轴向尺寸加工精度可控制在±10μm,同一电极加工的平台尺寸一致性可控制在±2μm。分析了电极损耗对零件形状精度的影响规律以及平台表面粗糙度的影响因素,并通过负极性加工去除电极损耗对平台尺寸精度的影响。     

平面磁控阴极用于PEPC等离子体放电实验研究

 平面磁控阴极用于大面积等离子体放电具有大幅降低放电电压和放电气压的优点,是PEPC首选的放电途径。通过对不同尺寸、不同磁场强度和不同气压状态下放电实验研究表明：在较宽的磁场强度范围内都可实现全口径的均匀等离子体放电,电极几何尺寸的小量变化对放电均匀性的影响不大。给出了满足300mm×300mm放电腔的放电参数。     

平面磁控阴极用于PEPC等离子体放电实验研究

平面磁控阴极用于大面积等离子体放电具有大幅降低放电电压和放电气压的优点 ,是PEPC首选的放电途径。通过对不同尺寸、不同磁场强度和不同气压状态下放电实验研究表明 :在较宽的磁场强度范围内都可实现全口径的均匀等离子体放电 ,电极几何尺寸的小量变化对放电均匀性的影响不大。给出了满足 30 0 mm× 30 0 mm放电腔的放电参数。     

辉光放电触发双级赝火花开关北大核心CSCD

设计了一种辉光放电触发双级赝火花开关,主要是阴阳电极、中间栅极和辉光放电腔的设计。通过增加中间栅极,构成双级结构,选用平板形结构,板厚1.5mm,栅极孔尺寸1mm,三个栅孔均匀分布在直径5mm的圆环上。辉光放电腔设计工作区域为Paschen曲线最低点左侧,具有放电电流大、触发电压低等特点。实验表明:双级赝火花开关需采用RC外均压电路,使阳极电压在两间隙中均匀分配。在充电1～57kV条件下,开关均能可靠触发导通。当阳极充电57kV时,在50Ω负载上获得了约56kV、抖动1.4ns的输出。     

等离子体电极电光开关大面积辉光放电的产生及其特性

 在电光开关的晶体两侧，用辉光放电产生的高电导率透明等离子体作为施加开关脉冲电压的电极，可大大增加开关的通光口径。利用设计建造的一个80mm×80mm口径的等离子体电极电光开关，研究了用于电光开关中的大面积辉光放电的产生方法及放电特性。描述了等离子体电极普克尔盒的结构、放电室和电极的几何尺寸、放电电路及其参数，实验观测了预电离和工作气压对放电的影响。     

不同电极结构下介质阻挡放电电离特征的试验研究

由于具有工作气压高、放电均匀等特点,大气压介质阻挡放电成为近年来非平衡等离子体领域研究的主要技术。电极结构是电离特性的主要影响因素之一,因此,通过电极结构优化来改善电离特性,对等离子体放电设备的应用领域拓展及性能优化至关重要。为改善大气压介质阻挡放电的电离特性,产生高活性、高均匀性的低温等离子体,基于自主设计的同轴介质阻挡放电装置进行了不同电极结构的电离试验及参数诊断;在一个标准大气压、放电频率11.4 kHz、放电峰值电压5.4～13.4 kV条件下进行了氩气电离试验;采用原子发射光谱法（AES）对氩等离子体谱线的激发、分光进行了检测分析;研究了螺纹电极、齿状电极、圆柱电极放电的特征光谱参数及外施电压对介质阻挡放电特征参数的影响。结果表明,齿状电极放电所形成等离子体的放电强度更大且放电效果显著,电子平均能量利用率低,电子激励温度弱于圆柱电极;圆柱电极放电强度较弱,但易形成大面积均匀性等离子体;大气压环境下电子激励温度不因外源电压的升高而单调递加,这表明通道内微放电的主要特征并不依赖于外施电压的供给,而是取决于电极结构、气体组份、气体压强;增大外施电压仅能增加单位时间内微放电的数量,经整合电子激励温度可达3 500 K,符合典型的低温等离子体特征。     

TE（A）激光器中放电电极的设计与选择

介绍了TE（A）激光器中Rogowski电极和近似Rogowski电极、Chang电极和紧凑式Chang电极、两类Ernst电极和紧凑式Ernst电极的设计方法。给出了上述放电电极的面型和表面电场分布，简述了制造上述电极的注意事项。在同等电场均匀度和均匀电场分布范围的情况下，对比了保角映射型电极的尺寸大小和电场分布特点。综合放电电极的面型、制造难度、辉光放电实验可知，在要求高能量和高功率的场合下，选择Ernst电极较好；在脉冲激光指标要求一般的场合下，选择近似Rogowski电极较好。     

水中脉冲放电金属电极烧蚀机理

采用板-板电极, 在放电间隙距离为2 mm、放电电流峰值为22 kA条件下, 对黄铜、钨铜电极的烧蚀特性进行了对比研究。利用高精度天平测量放电过程中的电极质量损失, 分别获取了阴极、阳极及总的平均烧蚀速率。通过放电后电极表面微观形貌、微观元素组成的分析及液体中金属离子的含量分析, 对水中脉冲放电金属电极的烧蚀机理进行了探讨。结果表明, 水中脉冲放电时, 钨铜电极的抗烧蚀性能明显高于黄铜电极。黄铜电极的主要烧蚀是以中心的大量孔洞及其边缘的波纹结构为表现形式的液体金属的溅射;钨铜电极的突出物及较平整的表面暗示了气相侵蚀的作用。以电弧的焦耳热效应为催化剂, 钨铜与水的电化学反应更为强烈, 因此电化学腐蚀是水中放电电极烧蚀的形式之一。     

常压针-板放电等离子体密度演化

分别采用Stark展宽法、图像法诊断等离子体电子密度,研究常压针-板放电等离子体电子密度随放电参数的演化.实验结果表明,降低电源的脉冲频率,减小等离子体的电极间距和采用细径电极,都有助于提高等离子体密度.利用全局模型分析影响电子密度变化的因素可知,随着脉冲频率的下降,等离子体放电体积减小,导致电子密度上升.在电极间距减小的过程中,电子密度变化则是降低等离子体吸收功率与减小放电体积共同作用的结果,其中放电体积的减小起到了更为主导的作用,导致电子密度上升.此外,采用细径电极也可以使等离子体放电体积减小,从而有利于获得较高的电子密度.     

一步和两步法制备阳极氧化铝模板(英文)

手二步阳极氧化法制备了大面积上有规则排列纳米洞的阳极氧化铝模板。与一步阳极氧化法的结果进行了比较,SEM测量表明,一步阳极氧化得到的AAO模板正面(对着负电极的一面)和反面,有很大不同,正面纳米洞的分布更不规则,而二步法得到的模板正反面都有排列规则的纳米洞。这一结果也表明阳极氧化过程是一种自组织有序的过程,氧化时间越长,纳米洞的分布越规则越均匀     

Oxygen permeation studies on La0.8Sr0.2Ga0.75Mg0.15Co0.10O3±δ

Oxygen permeation measurements were carried out on La_0.8Sr_0.2Ga_0.75Mg_0.15Co_0.10O_3±δ specimens of different thickness at temperatures between 673 and 1173 K under various gradients of oxygen partial pressure. Simultaneously, the open circuit cell voltage was measured. It was shown that the investigated compositions were characterized by a high oxygen permeation rate, and, consequently, by a high electronic conductivity. The electrode polarization effect was experimentally proved, and the influence of the measurement conditions on the degree of the electrode polarization effect was studied and discussed in detail. In particular, this mentioned influence was found to be sufficiently smaller at higher oxygen partial pressures in the cathode (oxygen-rich) compartment, while the change of p_O2 on the anode (oxygen-lean) side of the permeation cell did not lead to any sufficient electrode polarization. The values of the hole conductivity calculated from the experimental results found to be at least influenced by electrode polarization were used for calculations of the hole conductivity. The comparison of these values with results obtained by other experimental techniques (by p_O2-dependence of the total conductivity measured using impedance spectroscopy and Hebb–Wagner-polarization technique) demonstrated a satisfactory agreement.     

黑腔诊断孔堵口现象的数值模拟

 提出一个用一维数值模拟方法研究黑腔诊断孔的堵口现象模型。它被用来研究黑腔诊断孔的出射光透过率及其变化规律。计算结果表明,主要挡光区的径向运动尺度与靶宽度可比,因而一维平板模拟近似模拟诊断孔堵口现象是合理可行的;主要挡光区的密度基本上满足r >0.2 gcm^-3的规律;等离子体层的横向膨胀使得光透过率增大,在膨胀因子为0.8时计算得到在神光II激光条件下典型黑腔的加权平均透过率为0.75。     

Perceptual adaptation by normally hearing listeners to a simulated "hole" in hearing

Simulations of cochlear implants have demonstrated that the deleterious effects of a frequency misalignment between analysis bands and characteristic frequencies at basally shifted simulated electrode locations are significantly reduced with training. However, a distortion of frequency-to-place mapping may also arise due to a region of dysfunctional neurons that creates a "hole" in the tonotopic representation. This study simulated a 10 mm hole in the mid-frequency region. Noise-band processors were created with six output bands (three apical and three basal to the hole). The spectral information that would have been represented in the hole was either dropped or reassigned to bands on either side. Such reassignment preserves information but warps the place code, which may in itself impair performance. Normally hearing subjects received three hours of training in two reassignment conditions. Speech recognition improved considerably with training. Scores were much lower in a baseline (untrained) condition where information from the hole region was dropped. A second group of subjects trained in this dropped condition did show some improvement; however, scores after training were significantly lower than in the reassignment conditions. These results are consistent with the view that speech processors should present the most informative frequency range irrespective of frequency misalignment.     

Hole Injection Enhancement of MoO_3/NPB/Al Composite Anode

An ultra-thin molybdenum(VI) oxide(MoO_3) modification layer can significantly improve hole injection from an electrode even though the MoO_3 layer does not contact the electrode. We find that as the thickness of the organic layer between MoO_3 and the electrode increases, the hole injection first increases and it then decreases.The optimum thickness of 5 nm corresponds to the best current improvement 70%, higher than that in the device where MoO_3 directly contacts the Al electrode. According to the 4,4-bis[N-(1-naphthyl)-N-phenyl-amino] biphenyl(NPB)/MoO_3 interface charge transfer mechanism and the present experimental results, we propose a mechanism that mobile carriers generated at the interface and accumulated inside the device change the distribution of electric field inside the device, resulting in an increase of the probability of hole tunneling through the injection barrier from the electrode, which also explains the phenomenon of hole injection enhanced by MoO_3/NPB/Al composite anode. Based on this mechanism, different organic materials other than NPB were applied to form the composite electrode with MoO_3. Similar current enhancement effects are also observed.     

Development of electrochemical oxygen meter for liquid sodium

The development of an electrochemical oxygen meter for liquid sodium is briefly accounted. The current design, based on a solid electrolyte crucible machined out of a sintered pellet is described along with some technological details. Present experience with testing in sodium loops and post-exposure analysis has shown that the chosen assembly is capable of achieving approximately the Nernst voltage. The service period was limited mainly by corrosion and by some incompatibilities in reference electrode compartment materials.     

Numerical analysis and design of patterned electrode liquid crystal microlens array with dielectric slab

The phase profile of hole patterned electrode liquid crystal (LC) microlens array (MLA) was studied by a numerical method. It indicated that the formation of inverse domain and tilt wall in the liquid crystal cell limits the optical performance of the microlens array. The physical mechanism that determines the formation of inverse domain and tilt wall was elucidated by analyzing the phase profile and the liquid crystal director distribution. According to our numerical results, a new configuration for hole patterned electrode liquid crystal microlens array was proposed by introducing a dielectric slab between the patterned electrode and the liquid crystal. The physical parameters that influence the optical performance of this new configuration LC MLA were studied, which provide fundamental information for the design. The results indicate that the phase profile and focusing power of the new configuration is greatly improved.     

圆芯型边孔光纤双折射的有限元分析

对网芯型边孔光纤固有双折射的研究结果进行了报道。在对边孔光纤固有烈折射的产生机理和计算原理进行研究的基础之上,采用有限元法分析了网芯型边孔光纤的内部应力分布和双折射的大小。研究结果表明圆芯型边孔光纤的几何双折射较小,以应力双折射为主;边孔的存在导致光纤纤芯和包层区域的应力分布发生了较大的变化。文章提出了两边孔的连线方向为边孔光纤的快轴方向．并就不同的边孔结构对光纤双折射的影响进行了研究,发现网芯网孔型边孔光纤的同钉双折射随边孔张角的增加而成指数关系增长．可通过增大边孔半径和减小两孔间距提高边孔光纤的双折射。     

Enhanced performance of the OLED with plasma treated ITO and plasma polymerized thiophene buffer layer

In this work, indium-tin-oxide (ITO) electrode in organic light emitting device (OLED) was modified by using an O₂ plasma treatment and plasma polymerized thiophene buffer layers were inserted between ITO (anode) and organic layer in order to improve the hole injection efficiency. Furthermore, electron injection to cathode (Al) in the test OLED seemed to be improved due to introduction of quantum well in the cathode. The plasma-polymerized thiophene buffer layer on the O₂ plasma-treated transparent ITO electrode seemed to result in formation of a stable interface and consequently, reduction the hole mobility, which in turn caused enhanced recombination of hole and electron in the emitting layer. Compared with the test device without buffer layer, the turn-on voltage of the test device with the buffer layer was lowered by 1.0 V.