Experiment on inducing apoptosis of melanoma cells by micro-plasma jet

As a promising cancer treatment method,cold atmospheric plasma has received widespread attention in recent years.However,previous research has focused more on how to realize and expand the anti-cancer scope of plasma jet.There are also studies on the killing of small-scale cancer cells,but the effects of plasma jet on normal cells and normal cell clusters have been ignored.Therefore,we proposed a 50μm sized micro-plasma jet device,and used the device to treat melanoma cells(A-375)and human glial cells(HA1800)to evaluate their anti-cancer effects and effects on normal cells.The experimental results show that this kind of micro-plasma jet device can effectively inactivate cancer cells in a short period of time,while having little effect on normal cells.This work provides a certain experimental basis for the application offine plasma jet to clinically inactivate cancer cells.

Micro-Plasma闪耀离子束治疗40例萎缩性痤疮瘢痕疗效观察

[背景]观察Micro-Plasma闪耀离子束治疗面部皮肤痤疮萎缩性瘢痕的临床疗效.[病例报告]给40例萎缩性痤疮瘢痕患者行Micro-Plasma闪耀离子束治疗,分别记录术前、第1,2,3次治疗后患者术后评价、术后皮肤反应、医师综合评测、不良反应等情况,并进行对比分析.均按照5级评分标准对疗效及患者满意度加以评估.结果见,利用Micro-Plasma闪耀离子束治疗痤疮萎缩性瘢痕疗效满意率为82.6%.[讨论]Micro-Plasma闪耀离子束治疗痤疮萎缩性瘢痕安全、有效.

Study of Multi-Function Micro-Plasma Spraying Technology

A multi-functional micro-arc plasma spraying system was developed according to aerodynamics and plasma spray theory. The soft switch IGBT （Insulated Gate Bipolar Transistor） invert technique, micro-computer control technique, convergent-divergent nozzle structure and axial powder feeding techniques have been adopted in the design of the micro-arc plasma spraying system. It is not only characterized by a small volume, a light weight, highly accurate control, high deposition efficiency and high reliability, but also has multi-functions in plasma spraying, welding and quenching. The experimental results showed that the system can produce a supersonic flame at a low power, spray Al2O3 particles at an average speed up to 430 m/s, and make nanostructured AT13 coatings with an average bonding strength of 42.7 MPa. Compared to conventional 9M plasma spraying with a higher power, the coatings with almost the same properties as those by conventional plasma spray can be deposited by multi-functional micro-arc plasma spraying with a lower power plasma arc due to an improved power supply design, spray gun structure and powder feeding method. Moreover, this system is suitable for working with thin parts and undertaking on site repairs, and as a result, the application of plasma spraying will be greatly extended.

Salt spray corrosion test of micro-plasma oxidation ceramic coatings on Ti alloy

Ceramic coatings were prepared on Ti-6Al-4V alloy in NaAlO2 solution by micro-plasma oxidation （MPO）. The salt spray tests of the coated samples and the substrates were carded out in a salt spray test machine. The phase composition and surface morphology of the coatings were investigated by XRD and SEAM. Severe corrosion occurred on the substrate surface, while there were no obvious corrosion phenomena on the coated samples. The coatings were composed of Al2TiO5 and a little α-Al2O3 and mille TiO2, and the salt spray test did not change the composition of the coatings. The weight loss rate of the coatings decreased with increasing MPO time because of the increase in density and thickness of the coatings. The surface morphology of the coatings was influenced by salt spray corrosion test. Among the coated samples, the coating prepared for 2 h has the best corrosion resistance under salt spray test.

Formation and structure of composite coating of HDA and micro-plasma oxidation on A3 steel

Composite coatings were obtained on A3 steel by hot dipping aluminum(HDA) at 720 ℃ for 6 min and micro-plasma oxidation(MPO) in alkali electrolyte. The surface morphology, element distribution and interface structure of composite coatings were studied by means of XRD, SEM and EDS. The results show that the composite coatings obtained through HDA/MPO on A3 steel consist of four layers. From the surface to the substrate, the layer is loose Al2O3 ceramic, compact Al2O3 ceramic, Al and FeAl intermetallic compound layer in turn. The adhesions among all the layers are strengthened because the ceramic layer formed at the Al surface originally, FeAl intermetallic compound layer and substrate are combined in metallurgical form through mutual diffusion during HDA process.Initial experiment results disclose that the anti-corrosion performance and wear resistance of composite coating are obviously improved through HDA/MPO treatment.

Compounded Surface Modification of ZK60 Mg Alloy by High Current Pulsed Electron Beam+Micro-plasma Oxidation

In this study, compounded surface modification technology-high current pulsed electron beam （HCPEB） ＋ micro-plasma oxidation （MPO） was applied to treat ZK60 Mg alloys. The characteristics of the microstructure of ZK60 Mg alloy after single MPO and HCPEB＋MPO compounded treatment were investigated by SEM. The results showed that the density of the ceramic layer of HCPEB＋MPO-treated ZK60 Mg alloy was improved and defects were reduced compared to that under MPO treatment alone. Surface modified layer of ZK60 Mg alloys treated by HCPEB＋MPO was divided into three zones, namely the top loose ceramic zone, middle compact zone and inside HCPEB-induced melted zone. Corrosion resistance of ZK60 Mg alloy before and after the compounded surface modification was measured in a solution of 3.5% NaCl by potentiodynamic polarization curves. It was found that the corrosion current density of ZK60 Mg alloys could be reduced by about three orders of magnitude, from 311μA/cm^2 of the original sample to 0.2μA/cm^2 of the HCPEB＋MPO-treated sample. This indicates the great application potential of the HCPEB＋MPO compounded surface modification technology in improving the corrosion resistance of ZK60 Mg alloys in the future.

Composition and structure of coatings on Ti-6Al-4V alloy by micro-plasma oxidation in NaAlO2 solution

Compound ceramic coatings on Ti-6Al-4V alloy were prepared for different time by pulsed bi-polar micro-plasma oxidation (MPO) in NaAlO2 solution. The phase composition was studied by XRD. And the electrochemical impedance spectra (EIS) of the coatings were measured to study the structure of the coatings, combined with the surface morphology. Using the proper EIS interpreting software, the "equivalent circuit" of the coatings was established, and meanwhile fitting values of equivalent element were obtained. The results show that the coating is composed of Al2 TiO5, α-Al2O3 and rutile TiO2, of which Al2 TiO5 is the main crystalline. Increasing the MPO time, the contents of Al2TiO5, rutile TiO2 and α-Al2O3 in the surface of the coating increase. And the EIS analysis and the surface morphology of the coatings illustrates the double-layer structure of the coatings, and the outer layer is loosen and the inner layer is compact. With the increase of the oxidizing time, the surface coarse degree of the coatings and the porosity of the outer layer of the coating are increased while the compactness of the inner layer of the coating is improved.

Effect of Spraying Parameters on the Microstructure and Mechanical Properties of Micro-Plasma Sprayed Alumina-Titania Coatings

Electrical property of a micro-plasma spray system with different working-gas feed- ing schemes was tested to optimize the plasma spray process. The arc voltage with an integrated gas injection mode is higher than that with radial injection or axial injection modes. Thus, an integrated gas injection mode with an excellent electrical characteristic was adopted to deposit alumina-titania coating. The microstructure, bonding strength and hardness of the plasma sprayed alumina-titania coating, as a function of the spraying parameters, e.g., plasma current, gas flow rate and gas pressure, were studied. It was shown that the spraying parameters affected remarkably on the microstructure of the coating. Different tendencies in bonding strength and hardness were also shown for different spraying parameters. At an arc current of 250 A, a gas flow rate of 20 L/min and a gas pressure of 0.5 MPa, the bonding strength and micro-hardness of the coatings reach 40.6 MPa and HV1406.1, respectively.

Compound Ceramic Coatings Grown by Micro-plasma Oxidation on Ti-6Al-4V Alloy

Compound ceramics coatings on the Ti-6Al-4V alloy were prepared by the direct current micro-plasma oxidation （MPO） in NaAlO2 solution. The composition and morphology of the coatings were studied with the X-ray diffraction （XRD） and the scanning electron microscopy （SEM）, respectively. Inductively coupled plasma atomic emission spectrometer technique was used to analyze the solution features of Ti-6Al-4V alloy in the process of preparation. The results reveal that Al2TiO5 forms in the coatings at the initial stages of MPO reaction, and its content changes rapidly with the reaction continuing： after 20 min, the ceramics coatings are composed of α-Al2O3, 7-Al2O3 and Al2TiO5, but after 40 min, its main composition is of α-Al2O3. The content of Ti in the solution will increase when the MPO time extends, and as will Al in the anode area until, after 30 min, it reaches the maximum and keeps constant from then on. Both substrata of Ti and Al in the electrolyte join the MPO reaction at the initial stage, where the formation of Al2TiO5 happens; but as the MPO reaction prolongs, more and more Al in the electrolyte will take part in the reaction, leading to the appearance of a large amount ofAl2O3.

Methane conversion into higher hydrocarbons with dielectric barrier discharge micro-plasma reactor

We reported a coaxial,micro-dielectric barrier discharge(micro-DBD)reactor and a conventional DBD reactor for the direct conversion of methane into higher hydrocarbons at atmospheric pressure.The effects of input power,residence time,discharge gap and external electrode length were investigated for methane conversion and product selectivity.We found the conversion of methane in a micro-DBD reactor was higher than that in a conventional DBD reactor.And at an input power of 25.0 W,the conversion of methane and the total C2+C3 selectivity reached 25.10% and 80.27%,respectively,with a micro-DBD reactor of 0.4 mm discharge gap.Finally,a nonlinear multiple regression model was used to study the correlations between both methane conversion and product selectivity and various system variables.The calculated data were obtained using SPSS 12.0 software.The regression analysis illustrated the correlations between system variables and both methane conversion and product selectivity.

Compound Ceramic Coatings on Ti-6Al-4V by Micro-Plasma Oxidation in NaAlO_2 Solution

Micro-plasma oxidation (MPO) technique is a new technique by which compound ceramic coating can be grown in situ on Al, Ti, Mg and many other valve-metals. Compound ceramic coatings on Ti-6Al-4V alloy were prepared for different time by pulsed bi-polar MPO in NaAlO2 solution. The phase composition, morphology and the element distribution of the coatings were studied by XRD, SEM and JEOL SUPERPROBE 733 electric probe, respectively. Electrochemical Impedance Spectra (EIS) of the coatings were measured to study the structure character of the coatings. Through the proper EIS interpreting software, the "equivalent circuit" of the coatings was established, and the fitting values of equivalent element were calculated. The coating is mainly composed of Al2TiO5, a-A12O3 and rutile TiO2. The content of Ti element in the coating is less than that of substrate; its distribution is relatively uniform, and Ti in the outer layer is less than that in the inner layer. The content of Al in the coating is more than that of substrate, and its distribution is not even: Al in the middle part is more than that on both sides of the coating; And the EIS analysis has illustrated the double-layer structure of the coatings, and the outside layer is loosen and the inner layer compact; with the increase of the oxidizing time, the surface roughness of the coatings, and the porosity of the outer layer of the coating are increased while the compactness of the inner layer of the coatings are improved.

冷等离子体和微量润滑复合微铣削铝锂合金的表面性能研究

铝锂合金的延展性造成材料对刀具的粘附,会导致毛刺和积屑瘤等问题产生。为此,采用冷等离子体和微量润滑复合微铣削的方法加工铝锂合金,研究了工件的表面性能,并与单纯的干式、冷等离子体和微量润滑方法进行了对比。结果表明冷等离子体不仅改善了纳米流体在工件表面的浸润性,而且提高了材料的去除效率;相比于单纯的干式、冷等离子体和微量润滑方法,冷等离子体和微量润滑复合条件下的微铣削力分别降低了52.9%、42.9%和17.5%,而三维表面粗糙度Sa分别降低了67.3%、44.8%和33.3%。

新型KTN衬底上生长金刚石及其光催化性能研究

采用微波等离子体化学气相沉积技术,以钽铌酸钾(KTa1-xNbxO3,简称KTN)作为衬底,生长高质量金刚石薄膜。用X射线衍射仪、扫描电子显微镜和拉曼光谱仪观察并分析金刚石薄膜的表面形貌和微观结构,并研究样品的光催化性能。结果表明:金刚石生长过程中形成了碳化钽过渡层;随着生长时间延长金刚石质量不断提高;所有样品均表现出良好的降解罗丹明B的能力,其中生长时间为12 h的样品对罗丹明B的降解效率提高了0.29倍,与生长时间为3 h的样品相比其降解效率提高了1.6倍。本研究为生长多晶金刚石提供新型衬底,并探索金刚石在光催化方面的应用。

航空发动机叶片微束等离子堆焊转角焊缝模型研究

航空发动机叶片修复时,将受损部位切除后在新平面上进行多层多道焊接,在焊缝转角区域特别是转角点,因焊接工艺难以匹配导致过多熔滴进入熔池增加了焊缝熔高与熔宽,造成焊缝凸起,影响焊接质量。针对微束等离子焊接叶片转角区域焊缝的这种特征,建立了转角区域焊缝模型。首先利用抛物线曲线拟合建立了单道焊缝模型,并通过实验验证该模型能准确地表征单缝外形轮廓。然后提出了一种双焊缝转角重叠的焊缝成型模型。实验表明,采用该转角焊缝模型能够极大地降低转角区域焊缝的凸起,能满足航空发动机叶片修复精度的要求。

基于弧压反馈的叶片微束等离子焊接修复弧长跟踪控制

在损伤航空发动机涡轮叶片微束等离子增材修复过程中,多层堆焊后熔覆层面不平整导致凸起形貌产生,使得待修复表面与熔覆层上表面一致性差。提出一种基于弧压反馈的弧长跟踪控制方法,提高弧长稳定性,以解决上述问题。利用电弧电压信号间接表征电弧弧长,并提出变分模态分解与中位值平均滤波融合算法以去除噪声信号。在此基础上,设计一种变论域模糊PID与PID并联的控制器,调节焊枪的高度以实现弧压稳定,并进行仿真优化。最后搭建弧压采集与弧长控制平台,进行弧压信号去噪实验和表面凸起试片焊接实验。结果表明,此方法能显著提高弧长稳定性,且凸起表面与熔覆层上表面一致性好。

CF_(4)-GMET和G-PT处理对AR+AF涂层耐磨性能的影响

目的在兼顾涂层抗反射性和疏水性的前提下,通过强化抗反射(AR)多层复合膜系与抗指纹(AF)涂层之间的黏附力,提升复合涂层的机械耐久性能。方法采用磁控溅射法在玻璃衬底上沉积AR多层复合膜系,首创性地采用CF_(4)气体微刻蚀(CF_(4)-Gas Micro-etching Treatment,CF_(4)-GMET)与石墨等离子体(Graphite Plasma Treatment,G-PT),依次对AR膜系表面进行处理后,将AF试剂蒸镀附于AR层表面并冷却,即可得到具有超强耐磨性的AF/CF_(4)-GMET&G-PT SiO_(2)/AR抗反射疏水涂层。结果CF_(4)-GMET对AR表层SiO_(2)处理后,其表面“柱状尖峰”消失,得到低粗糙度针状表面,并增大了SiO_(2)与AF涂层的接触比表面积。G-PT处理大幅提高了表层SiO_(2)亲水性,从而使得SiO_(2)表面黏附功增大。经2道工艺处理后,SiO_(2)表面粗糙度降低,黏附功先降后升为最大值,蒸镀AF疏水涂层后界面结合最为稳定,耐磨性能显著增强。在负载为1000 g的钢丝绒摩擦10000次后,抗反射疏水涂层的水接触角(WCA)从117.7°下降至113.6°,磨损率仅为3.4%,耐磨性能极佳。结论对AR膜系表层SiO_(2)进行CF_(4)-GMET和G-PT处理,能显著提高抗反射疏水涂层的耐磨性能,而对光学透过率基本无影响。

微纳电极阵等离子体微系统

发现微纳尺度结构效应能调控电荷分布,在空间中激励形成极化带电场,极化带电场中原子、分子间相互作用的特异性产生了极化带效应。设计产生极化带效应的微纳电极阵结构,通过非硅微/纳加工技术集成形成微纳电极阵等离子体微系统(NPMEMS),NPMEMS可集中或分布式地调控物质状态、产生极化带等离子体,利用其特殊的理化性能可大幅提高应用系统效率,或解决多个领域中应用技术的机理性难题。

微束水蒸气等离子弧焊在空调铜管钎焊中的应用

铜管是制冷设备的重要原材料,生产中通常采用气体火焰钎焊对铜管接头进行焊接。但传统的气体火焰钎焊存在诸多缺点,故引入微束水蒸气等离子弧焊工艺方法,探究其焊接铜管的可行性并确定出合适的焊接工艺参数。通过对5组不同规格的铜管接头在6个焊接电流档位下分别进行焊接试验,对试验样本焊后的外观和内部结构进行观察、分析、对比,验证了该方法相比于气体火焰钎焊方法的有效性,并获得了各类铜管接头合适的焊接电流档位。与气焊相比,使用微束水蒸气等离子弧焊工艺在合适的焊接工艺参数下进行焊接,具有较高的效率、稳定性、易用性和安全性,能够为空调铜管的焊接和维修提供一种新的工艺方法。

Micro-plasma noise of 30 krad gamma irradiation broken-down GaN-based LED

A correlation model between micro plasma noise and gamma irradiation of GaN-based LED is built.The reverse bias I-V characteristics and micro-plasma noise were measured in it, before and after Gamma irradiation. It is found that even after 30 krad Gamma irradiation, the GaN-based LED has soft breakdown failure. The reverse soft breakdown region current local instability of this device before irradiation is analyzed by the microplasma noise method. The results were obtained that if the GaN-based LED contained micro-plasma defects, it will fail after low doses（30 krad） of gamma irradiation. The results clearly reflect the micro-plasma defects induced carriers fluctuation noise and the local instability of GaN-based LED reverse bias current.

ICP深硅刻蚀工艺研究

深硅刻蚀工艺是MEMS器件制造过程中的关键工艺之一。加速度计的梳齿结构、滤波器及压力传感器的硅腔结构都是决定器件性能的关键工艺,均需要通过深硅刻蚀制备。梳齿的垂直度以及硅腔的侧壁平整度均会对器件的性能产生直接影响。针对深硅刻蚀工艺中出现的形貌问题进行分析,找到影响硅草、侧壁垂直度差、底部横向钻蚀、侧壁钻蚀等问题的工艺参数。最后通过工艺参数优化,对这些问题进行改善,从而获得理想形貌,满足器件性能要求。