表面电晕预电离与火花预电离之比较

本报道了表面电晕预电离与火花预电离的比较结果，针式火花预电离源利用热电弧发出强烈的紫外光，其发射光谱范围从可见光连续延伸到紫外，表面电晕预电离源，通过介质极化发射电子，在预电离电路中产生电晕电流，其强度决定了发射光子的数量，而发射电子的能量分布确定辐射的光谱分布，其发射光谱分布不连接，对两种预电离源的放电电压和电流进行测量，得到瞬态信息，计算得到火花预电离源中消耗的能量约是表面电晕预电离源的400倍，比较分析可知，表面电晕预电离的效率远离于火花预电离。     

电晕放电与塑料表面处理

本文简介了电晕放电处理对塑料表面的改性原理。对电晕放电处理引起的塑料表面的化学变化、物理变化、表面润湿性、粘接性以及影响电晕放电处理的各种因素进行了讨论。     

电晕放电处理对高密度聚乙烯表面作用的研究

本文研究了高密度聚乙烯(HDPE)经电晕放电处理后表面形态及性能的变化,通过接触角测定、多重内反射红外光谱、扫描电镜、重量分析等手段,证实了多种气体均能在较短的时间内使HDPE的润湿性明显提高,含氧气体或非含氧气体都能对HDPE表面进行刻蚀,但它们有不同的刻蚀机理,含氧气体的放电处理可把含氧基团引入HDPE表面,且改变了HDPE表面的刻蚀过程。     

电晕方法在聚合物表面处理中的应用进展

介绍了电晕处理方法的原理与类别,以及电晕处理方法在聚合物材料表面处理中的应用,对电晕处理后聚合物表面的物理和化学变化进行了归纳和机理分析.     

镍-63——真空电子器件中新的预电离源

叙述了低能电子源 (β源 )的特点 ,比较了6 3Ni,3H和55Fe低能 β源的特性 ,介绍了6 3Ni放射源的制备方法 ,讨论了6 3Ni用作真空电子器件中预电离源的优点 ,列举了6 3Ni放射源在真空电子器件中的多种应用     

镍—63——真空电子器件中新的预电离源

叙述了低能电子源的特点，比较了＾６３Ｎｉ，＾３Ｈ和＾５５Ｆｅ低能β源的特性，介绍了６５Ｎｉ放射源的制备方法，讨论了＾６５Ｎｉ用作真空电子器件中预电离源的优点，列举了＾６５Ｎｉ源在真空电子器件中的多种应用。     

耐电晕聚酰亚胺薄膜表面电荷特性

为了解微纳米尺度下聚合物绝缘材料表面电荷生成、发展规律和机理,利用电场力显微镜（electrostatic force microscope,EFM）研究了两种聚酰亚胺薄膜的表面电荷生成及其衰减特性.采用EFM的导电探针在聚酰亚胺薄膜表面注入电荷,并对产生的电荷进行原位表征,结果表明原始（100 HN）和耐电晕（100 CR）两种聚酰亚胺薄膜上电荷生成和衰减特性不同.耐电晕薄膜被注入的表面电荷数量少且注入后衰减较快,其衰减服从指数规律,衰减时间常数为19.9 min;原始薄膜被注入的电荷量较多,衰减时间常数为48.1 min.分析表明,耐电晕薄膜中由于掺杂了Al2O3成分,使得材料的介电常数提高、电阻率下降.介电常数提高使得金属-电介质界面势垒提高,增加了电荷注入难度,导致表面电荷数量少;电阻率下降使得电荷消散速度加快.     

真空的激光电离测量技术的研究与发展

介绍了激光电离方法在真空测量方面的应用，总结了真空的激光电离测量技术的优点和面临的问题。     

热表面电离法监测锂原子蒸气密度的实验研究

本文介绍了热表面电离法监测锂(Li)原子蒸气密度的实验研究。制作了热表面电离计,分析了离子流与锂蒸气密度的关系,验证了热表面电离法监测锂原子蒸气密度的可行性。对原子与金属表面作用的机制、电荷交换的各种情况以及金属表面的物理化学性质进行了分析。     

填充介质对电晕放电特性的影响

为了研究填充介质对电晕放电的影响,本文采用针-板放电装置,研究了不同条件下正、负直流电晕放电的起晕电压、平均电流等特性,获得了正、负直流电晕放电和正脉冲电晕放电的时间积分图像及正脉冲电晕放电的时间分辨图像。还分析了介质尺寸、形状、填充密度以及介电常数对正脉冲电晕放电特性的影响。所得结果表明,填充介质导致正、负直流电晕起晕电压升高。正电晕放电更易于激发填充介质的表面放电,且尺寸小的介质颗粒更容易形成环绕颗粒表面的放电。在正脉冲电晕放电中,填充介质密度、介电常数越高,起晕电压越低;球状介质比圆柱形介质更容易形成表面放电。     

Nanoparticles in the Biological Context: Surface Morphology and Protein Corona Formation

A recent paper demonstrated that the formation of a protein corona is not a general property of all types of nanosized objects. In fact, it varies between a massive aggregation of plasma proteins onto the nanoparticle down to traces (e.g., a few proteins per 10 nanoparticles), which can only be determined by mass spectrometry in comparison to appropriate negative controls and background subtraction. Here, differences between various types of nanosized objects are discussed in order to determine general structure–property‐relations from a physico‐chemical viewpoint. It is highlighted that “not all nanoparticles are alike” and shown that their internal morphology, especially the difference between a strongly hydrated/swollen shell versus a sharp “hard” surface and its accessibility, is most relevant for biomedical applications.     

Corona Generation and Deposition of Metal Nanoparticles on Conductive Surfaces and Their Effects on the Substrate Surface Texture and Chemistry

A corona discharge ion bombardment technique was used successfully to generate gold particles of submicron diameters. In a negative corona discharge, the glow region contains electrons, negative ions, and positive ions. Positive ions collided with the negative corona tip electrode, causing it to sputter and emit fine particles of the electrode material. These nanoparticles were deposited on grounded metal substrates or thin mica sheets supported by grounded metal substrates. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to study the size distribution and deposition pattern of the metal nanoparticles. The diameter of these nanoparticles was dependent upon the material of the electrode and ranged from 20 to 450 nm for gold and from 15 to 240 nm for tungsten. The nanoparticles were deposited on aluminum, mica, and carbon steel test panels for different amounts of time. The electrochemical response of the carbon steel panels exposed to aerated salt solution was measured by direct current (DC) polarization technique before and after the gold nanoparticles were deposited. This technique was employed to determine the changes in the surface chemistry because of the presence of gold nanoparticles, and it proved to be a sensible method for detecting the presence of fine layers of nanoparticles on the metallic substrate. The presence of the gold nanoparticles increased the electrochemical potential E_corr from -0.640 V to -0.211 V, compared with the value for a noncorrosive surface, like that of pure gold, which is 0 V.     

SiOx高阻隔材料的电晕处理及其印刷特性

目的确定SiO_x阻隔材料的电晕特性与印刷特性,研究其电晕处理规律以及印刷色彩再现的能力。方法采用磁控共溅射方法在PET表面制备不同含量SiO_x的复合阻隔材料,并采用电晕放电进行处理,利用接触角表征电晕放电后表面状态的变化;采用彩色喷墨打印方式,对处理后的复合薄膜表面进行印刷测试。结果 SiO_x质量分数较小时不具备抗电晕特性,当SiO_x质量分数达到50%左右时,即产生了抗电晕能力。结论印刷测试结果表明,经过电晕处理的复合薄膜色彩再现良好,可直接进行印刷。     

负氢离子源负氢离子表面转化材料发展现状分析

负氢离子源已经成为核聚变装置中性束加热系统的首选离子源,中国的负氢离子源研究尚处于起步阶段。在本论文中,介绍负氢离子源的结构和工作过程,比较分析负氢离子的产生模式,着重对当前应用较多、具有应用前景的表面产生模式中负氢离子转化材料进行了介绍。掺铯的金属材料以其优异的特性成为当前负氢离子源的主要材料;La B6热阴极具有较好的负氢离子转化性能,但其复杂的结构和较短的寿命影响了其总体性能;高有序石墨仅仅在结构上具有一定的优势;结合热电子发射、场致电子发射和其他电子发射模式的金刚石膜材料具有较优异的性能预期和较好的前景。因此在未来的负氢离子源中,铯化金属材料和金刚石薄膜材料可能会成为用于表面转化的主要材料。     

聚酰亚胺驻极体的平均电荷重心迁移及电荷的贮存

本文利用开路 TSD 电流谱讨论了电晕充电期间热处理对聚酰亚胺薄膜驻极体电荷贮存稳定性的影响,分析了恒压电晕充电期间电荷的建立过程,研究了延长注极时间及在不同温度下电晕充电的聚酰亚胺薄膜沉积电荷平均深度向背电极的迁移规律。     

聚酰亚胺/二氧化钛纳米复合薄膜制备与耐电晕性

采用原位聚合法制备不同TiO₂组分聚酰亚胺(PI)/纳米TiO₂复合薄膜, 薄膜厚度50μm。 测试结果表明, TiO₂呈球状颗粒, 直径约为100 nm, 聚酰亚胺呈片状, 尺寸约为2μm×1μm。随着TiO₂含量的增加, 复合薄膜介电常数和介电损耗增大, 击穿场强先增加后降低; 在40 kV/mm电场强度下, 复合薄膜耐电晕老化寿命增加, 纯PI薄膜寿命为3 h, 20wt%TiO₂含量薄膜寿命达到25 h; TiO₂颗粒耐电晕能力强, 与聚合物形成界面相, 改变材料陷阱能级, 有利于空间电荷的扩散和热量的传输, 在薄膜表面形成放电阻挡层, 降低局部放电对薄膜内部的侵蚀, 显著提高薄膜耐电晕老化寿命。     

直流电晕放电净化羰基硫以及其产物分析

使用直流电晕放电净化羰基硫(COS),研究不同O_2浓度、不同相对湿度以及粉尘存在与否对COS处理效果和被处理后主要产物含量的影响。实验结果表明,随着O_2浓度增加,COS去除效率降低,出口气中SO_2、总硫(The totals except SO_2,记为TS′)生成率均减小,COS转化量与CO、CO_2总量保持平衡,CO、CO_2浓度降低,CO生成率降低,CO_2生成率增加。相对湿度对COS处理效果影响较小,但影响电源击穿电压,相对湿度增加,出口气中总硫生成率增加,SO_2生成率减小,出口气中CO生成率降低,而CO_2生成率增加,CO浓度降低,CO_2浓度增加。在实验过程中加入粉尘后,COS处理效果有一定提高,出口气中SO_2生成率显著减少,总硫生成率增加,出口气中CO浓度降低,生成率降低,CO_2浓度增加,生成率增加。低氧气浓度、低湿度以及粉尘存在的情况下,COS处理效果最好。     

The Crown and the Scepter: Roles of the Protein Corona in Nanomedicine

Engineering nanomaterials are increasingly considered promising and powerful biomedical tools or devices for imaging, drug delivery, and cancer therapies, but few nanomaterials have been tested in clinical trials. This wide gap between bench discoveries and clinical application is mainly due to the limited understanding of the biological identity of nanomaterials. When they are exposed to the human body, nanoparticles inevitably interact with bodily fluids and thereby adsorb hundreds of biomolecules. A “biomolecular corona” forms on the surface of nanomaterials and confers a new biological identity for NPs, which determines the following biological events: cellular uptake, immune response, biodistribution, clearance, and toxicity. A deep and thorough understanding of the biological effects triggered by the protein corona in vivo will speed up their translation to the clinic. To date, nearly all studies have attempted to characterize the components of protein coronas depending on different physiochemical properties of NPs. Herein, recent advances are reviewed in order to better understand the impact of the biological effects of the nanoparticle–corona on nanomedicine applications. The recent development of the impact of protein corona formation on the pharmacokinetics of nanomedicines is also highlighted. Finally, the challenges and opportunities of nanomedicine toward future clinical applications are discussed.     

Surface ionization on tungsten in a varying ambient atmosphere

Experiments show that under suitable conditions the introduction of oxygen can raise the surface ionization current emitted by a heated tungsten wire by several orders of magnitude. The ions in this case are alkali ions originating from alkali silicates normally present as additives in tungsten. From the simultaneous observation, in a varying ambient atmosphere, of both the positive ion current produced by surface ionization and of the electron current due to thermionic emission, it is concluded that the large observed increase in positive ion current is not primarily a consequence of an increase in the work function of tungsten, but is mainly due to a reduction in the residence time of the ions on the ionizing surface. This appears to be caused by alkali ions being preferentially replaced as an adsorbate on tungsten by the impinging oxygen molecules. The observations suggest that the increased ion production does not occur on the outer wire surface, but at inter-phase boundaries within the wire.