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。     

水中脉冲电晕放电测试系统

建立了一套水中电晕放电测试系统．由高速摄影系统、电参数测量系统和压力测量系统组成．高速摄影系统由GSJ转镜式高速摄影仪和德国产Pentazet35型摄影仪等组成,最高拍摄频率分别为250万幅／s和4万幅／s．电参数测量系统由高压表、电阻分压器、同轴分流器和Tektronix THS730A示波器组成．详细分析了整个系统的敏感设备、干扰源及其传播途径,并提出了相应的控制措施．压力测试系统主要有压电式传感器等组成．     

高压脉冲电晕放电氮等离子体的分子束质谱诊断研究

克服强电磁场干扰 ,以具有三级差分抽气系统的分子束质谱为手段 ,对线板式高压脉冲电晕放电N2 等离子体阴极板区的正离子成分进行了首次诊断研究。发现在各种实验条件下 ,N 离子流强度均显著大于N 2 ;N 及N 2 离子流强度随放电电压、放电频率升高而增大 ,随放电室气压变化则存在一极值。对N2 等离子体中所包含的主要基元物理 化学过程进行了讨论     

Corona Discharge Plasma Jet Inactivates Food‐borne Pathogens Adsorbed onto Packaging Material Surfaces

The potentiality of corona discharge plasma jet (CDPJ) for disinfection of food packaging materials, including glass, polyethylene, polypropylene, nylon and paper foil, was evaluated. CDPJ was generated using a high voltage (20 kV) pulsed DC power source, at 1.5 A current and 58 kHz frequency. The separation distance between plasma electrode and sample plate during the treatment was 25 mm. Upon treating food pathogens‐loaded packaging materials by the plasma, 4.5–5.0 log/cm² reductions (99.999%) in viable cell counts of Escherichia coli O157:H7 and Staphylococcus aureus were observed in 120 s. Another tested pathogen Salmonella Typhimurium was inactivated by 3.0 log/cm² units. The patterns of inactivation of pathogens are fitted well to Weibull tail model. Compared to untreated controls, the CDPJ‐treated packaging materials exhibited insignificant (p > 0.05) changes in the optical characteristics, tensile strengths, surface temperatures and strain‐induced deformation. Therefore, the most common food packaging materials harboring bacterial pathogens could be disinfected by the CDPJ without compromising physicomechanical properties of materials. Copyright © 2017 John Wiley & Sons, Ltd.     

减压电晕放电处理在聚酯片基底层工艺中的应用

本文扼要介绍了减压电晕放电处理在PET聚酯片基底层生产工艺中的应用，包括所用的设备和效果，并讨论了电晕处理对聚酯薄膜表面层所起的作用。     

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。     

氮氧混合气体高压脉冲电晕放电等离子体的分子束质谱诊断研究

利用具有三级差分抽气系统的分子束质谱仪为检测手段 ,对N2 ,O2 混合气体的线板式高压脉冲电晕放电等离子体阴极板区的正离子成分进行了诊断研究。实验结果表明 :在放电反应室N2 ,O2 混合气体压力 1330～ 332 5Pa ,峰值电压 4～10kV及放电重复频率 10～ 10 0Hz范围内 ,N+ 2 和O+ 流强相当 ,N+ 流强约为N+ 2 流强的 2～ 10倍。N+ ,N+ 2 和O+ 流强随脉冲峰值电压、放电重复频率的升高而增大 ,随放电气压的变化则存在一极值     

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.     

Electrostatic Evaluation of a Unipolar Diffusion and Field Charger of Aerosol Particles by a Corona Discharge

This article presents a unipolar diffusion and field charger by corona discharge is presented and electrostatically evaluated for charging aerosol particles. The electrostatic characteristics of the charger were investigated with an electrometer by measuring the ion number concentrations corresponding to the discharge and charging currents. The discharge and charging currents, and ion number concentration in the discharge and charging zones of the charger, increased with corona voltage. The magnitudes of the ion number concentration for positive and negative coronas in the discharge zone ranged from 1.34 × 10¹³ to 1.84 × 10¹⁵ ions/m³ and 7.34 × 10¹³ to 2.64 × 10¹⁵ ions/m³, respectively. For the charging zone, the ion number concentrations for positive and negative coronas ranged from 2.95 × 10¹³ to 1.52 × 10¹⁴ ions/m³ and 2.06 × 10¹³ to 1.47 × 10¹⁴ ions/m³, respectively. To predict the behavior of the electric field strength and lines in the discharge and charging zones of the charger, the electric field strength and distribution of the charger in the discharge and charging zones were calculated by a commercial computational fluid dynamics software package. Numerical calculation results of electric field distribution and lines through the inner electrode showed good agreement with experimental results. Also, the mean charge per particle for particle diameters were in the range of 0.01 to 50 µm for various operating conditions of the charger was theoretically evaluated. For both diffusion and field charging, lower aerosol flow rate and higher corona voltage resulted in an increase in the mean charge per particle within the charger. This simple charger proved to be particularly useful in diffusion and field charging of aerosol particles in particulate matter detector instruments for measuring PM10 and PM2.5 concentration.     

脉冲电晕等离子体烟气脱硫工业试验研究

利用建造在四川绵阳科学城热电厂的最大烟气处理量为20000m^3/h的脉 冲电晕等离子体烟气脱硫工业中试验装置，研究了影响脱硫效率的因素，获得了最佳工艺参数。研究结果表明，当烟气温度在65－70℃，烟气水分含量约10％，氨硫化学剂量比为1：1，烟气停留时间大于6s、能耗 低于5Wh/Nm^3等条件下，脱硫率达85％以上。     

Mechanistic Understanding of Protein Corona Formation around Nanoparticles: Old Puzzles and New Insights

Although a wide variety of nanoparticles (NPs) have been engineered for use as disease markers or drug delivery agents, the number of nanomedicines in clinical use has hitherto remained small. A key obstacle in nanomedicine development is the lack of a deep mechanistic understanding of NP interactions in the bio-environment. Here, the focus is on the biomolecular adsorption layer (protein corona), which quickly enshrouds a pristine NP exposed to a biofluid and modifies the way the NP interacts with the bio-environment. After a brief introduction of NPs for nanomedicine, proteins, and their mutual interactions, research aimed at addressing fundamental properties of the protein corona, specifically its mono-/multilayer structure, reversibility and irreversibility, time dependence, as well as its role in NP agglomeration, is critically reviewed. It becomes quite evident that the knowledge of the protein corona is still fragmented, and conflicting results on fundamental issues call for further mechanistic studies. The article concludes with a discussion of future research directions that should be taken to advance the understanding of the protein corona around NPs. This knowledge will provide NP developers with the predictive power to account for these interactions in the design of efficacious nanomedicines.     

液相化学还原法制备纳米银焊膏及其连接性

采用液相化学还原法制备出平均粒径为20~35nm的纳米银,并考察不同温度及PVP用量对纳米银性质的影响。结果表明:当硝酸银与PVP的质量比为1∶4、反应温度为30℃时,纳米银的平均粒径最小,为22.4nm,且其团聚程度最小,粒径分布最佳。在压力10MPa、温度200℃、保温30min的烧结条件下,利用制得的纳米银配制焊膏,连接纯度为99.9%的无氧紫铜板,通过扫描电镜(SEM)观察烧结接头截面形貌,可见烧结界面连接紧密,接头组织有孔隙存在。     

电晕放电法合成载铁碳纳米管

利用电晕放电增强化学气相沉积技术制备了载铁碳纳米管阵列,采用TEM、SEM和XRD等对载铁碳纳米管进行表征,发现了两种类型的碳纳米管,且含铁纳米颗粒无论大小均被包裹在碳纳米管的管壁中.IR热成像仪分析发现碳纳米管合成温度不高于250℃.     

纳米颗粒自组装SERS基底的发展及应用进展

表面增强拉曼散射(SERS)技术作为一种分析手段,因其高灵敏度、高选择性、及对样品的非破坏性等,在生物医药、环境检测、分析化学及食品安全等领域获得了广泛应用。金属纳米颗粒阵列因具有较强的局部表面等离子共振效应,能构造出高性能的SERS基底。自组装技术作为可制备出高度有序、可重复性高且结构可控的纳米阵列的方法,迄今仍是SERS基底构造研究领域中的热点。简单介绍了自组装技术的方法及其在SERS基底制备中的发展及应用,并对其未来发展趋势做出展望。     

电弧法制备碳包覆金属纳米微粒的研究进展

碳包覆金属纳米微粒既可以避免金属纳米微粒的氧化,又能保持其同有性能小变,其潜在科研和应用价值引起了研究者的广泛关注.本文介绍了电弧法制备碳包覆金属纳米微粒的原理,综合评述了碳包覆金属纳米微粒的电弧法制备技术的国内外研究现状,讨论了金属与碳作用后的反应路径,产物类型以及碳包覆金属纳米微粒的形成机理.     

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。     

羟基化SBS模板合成金纳米粒子及表征

以羟基化SBS为模板,N,N-二甲基甲酰胺(DMF)为溶剂,氯金酸为原料,硼氢化钠为还原剂,在一定反应条件下制备得到了金纳米粒子。采用紫外-可见光谱和透射电子显微镜等方法对所合成的纳米金样品进行了表征。结果表明,羟基化SBS可以为金纳米粒子的成核和长大起到较好的模板作用,金纳米粒子可以产生纳米金所具有的表面等离子态的特征吸收峰;改变合成条件,可以控制金纳米粒子特征吸收峰的位置;透射电子显微镜给出金纳米粒子具有球状形貌特征,且具有较窄尺寸分布。     

电弧放电等离子体法合成立方相氮化铬纳米粉

采用电弧放电等离子体方法,通过金属铬和氮气的直接反应合成了粒度小于10nm的纯立方相氮化铬（CrN）纳米粉.利用X射线衍射分析（XRD）、透射电镜(TEM)和傅立叶变换红外光谱（FT-IR）对不同氮气压下形成的产物进行了表征.研究了氮气压和氨气的加入对形成立方相CrN纳米晶的影响.研究结果表明：相对较低的N₂气压(5~20kPa) 有利于金属Cr向立方CrN的转化,可以使更多的氮原子结合到金属Cr的格子中去;活性氮源（氨气）的加入降低了金属Cr的氮化.     

The Influence of Nanoparticle Shape on Protein Corona Formation

Nanoparticles have become an important utility in many areas of medical treatment such as targeted drug and treatment delivery as well as imaging and diagnostics. These advances require a complete understanding of nanoparticles' fate once placed in the body. Upon exposure to blood, proteins adsorb onto the nanoparticles surface and form a protein corona, which determines the particles' biological fate. This study reports on the protein corona formation from blood serum and plasma on spherical and rod‐shaped nanoparticles. These two types of mesoporous silica nanoparticles have identical chemistry, porosity, surface potential, and size in the y‐dimension, one being a sphere and the other a rod shape. The results show a significantly larger amount of protein attaching from both plasma and serum on the rod‐like particles compared to the spheres. Interrogation of the protein corona by liquid chromatography–mass spectrometry reveals shape‐dependent differences in the adsorption of immunoglobulins and albumin proteins from both plasma and serum. This study points to the need for taking nanoparticle shape into consideration because it can have a significant impact on the fate and therapeutic potential of nanoparticles when placed in the body.     

Recovery of Drug Delivery Nanoparticles from Human Plasma Using an Electrokinetic Platform Technology

The effect of complex biological fluids on the surface and structure of nanoparticles is a rapidly expanding field of study. One of the challenges holding back this research is the difficulty of recovering therapeutic nanoparticles from biological samples due to their small size, low density, and stealth surface coatings. Here, the first demonstration of the recovery and analysis of drug delivery nanoparticles from undiluted human plasma samples through the use of a new electrokinetic platform technology is presented. The particles are recovered from plasma through a dielectrophoresis separation force that is created by innate differences in the dielectric properties between the unaltered nanoparticles and the surrounding plasma. It is shown that this can be applied to a wide range of drug delivery nanoparticles of different morphologies and materials, including low‐density nanoliposomes. These recovered particles can then be analyzed using different methods including scanning electron microscopy to monitor surface and structural changes that result from plasma exposure. This new recovery technique can be broadly applied to the recovery of nanoparticles from high conductance fluids in a wide range of applications.