纳秒激光加工微孔阵列铝膜的润湿性的实验及模拟

润湿性与固体材料表面的微观几何结构和表面化学组成密切相关,是固体材料表面的一个重要特性体现。文章用实验和仿真的方式研究了双面超亲水和双面超疏水表面的润湿特性。首先采用纳秒激光钻孔技术在厚度为35μm的铝箔上加工微孔阵列,得到了双面超亲水铝膜表面;然后将铝膜在十七氟癸基三乙氧基硅烷(PFDTES)浸泡20h,铝膜从双面超亲水表面改性为双面超疏水表面;研究了改性前后铝膜的液滴渗透情况。用COMSOL Multiphysics中的两相流分析模块研究了基于双面超亲水和双面超疏水状态下的微孔通道内的水渗透过程,仿真结果和实验结果基本一致,对实验起指导作用。     

辐射探测芯片吸收膜理论设计及镍磷黑膜制备

对新型条形辐射探测芯片的吸收膜层进行了理论分析,并且在金刚石材质的探测芯片上采用电镀方法制备了镍磷黑吸收膜.辐射探测芯片的膜层吸收分析表明,芯片吸收膜层的吸收率正比于表面粗糙度.通过对辐射吸收膜层设计与制作工艺的研究,制备出一种用于条形辐射探测芯片的镍磷黑吸收膜,通过测量其表面形貌结构,表明该膜层具有50nm—1.5μm范围的微结构;红外吸收测试表明其吸收率在1.4—8μm波段为0.989以上,从而提高了辐射探测芯片的性能.     

表面热透镜技术测量3.8μm和2.8μm激光薄膜的微弱吸收

 采用表面热透镜技术，对3.8μm和2.8μm激光辐照下镀制在Si基底上的单层ZnS，YbF₃和YBC薄膜及不同膜系的YbF₃/ ZnS多层分光膜和多层高反膜，以及镀制在CaF₂基底上的增透膜进行了吸收测量，并对3.8μm和2.8μm 激光的测量结果进行了比较分析。实验结果表明，2.8μm波长下的吸收比3.8μm的大得多，两者之间约相差一个量级，测得的多层高反膜YbF₃/ZnS薄膜在的3.8μm处的最低吸收为4.57×10^－4，测量系统的灵敏度约为10^-5。     

MPCVD方法制备军用光学元件纳米金刚石膜

介绍了用MPCVD方法制备纳米金刚石膜的工艺。用MPCVD方法实验研究了在光学玻璃上镀纳米金刚石膜:膜层厚度为0 4551μm,粒度小于200nm,表面粗糙度小于29 5nm,最大透过率为80%;平均显微硬度为34 9GPa,平均体弹性模量为238 9GPa,均接近天然金刚石的力学性能。与衬底材料表面应力-2 78GPa相比,具有较好的抗压和耐磨效果。     

利用界面层提高多孔铝阻尼能力的一种新方法

通过溶胶一凝胶法在多孔铝孔表面包覆一层厚度为100μm左右的聚苯乙烯薄膜。内耗测量表明，引入该界面层以后，多孔铝的阻尼能力有了非常显著的提高，甚至有了量级的变化。分析表明，借助界面层的微小滑移而耗能应该是阻尼能力提高的主要机制。同时也意味着利用有机高分子设计界面层从而提高相应多孔材料的阻尼能力是可行的、高效的。     

以非晶碳作硅基红外增透膜的实验研究

在室温下，用激光烧蚀石墨靶方法在单晶硅衬底表面沉积了不同厚度的非晶碳膜。对膜进行了表面形貌观察，测试并分析了膜的拉曼散射光谱和傅里叶变换红外光谱。发现膜同晶石墨杂质较少，观察到1200cm^-1附近的非晶金刚石拉曼峰，膜层在红外的光透过率高，在硅衬底上适宜于制作波长短于8μm的红外增透膜。     

利用界面层提高多孔铝阻尼能力的一种新方法

通过溶胶-凝胶法在多孔铝孔表面包覆一层厚度为100 μm左右的聚苯乙烯薄膜.内耗测量表明,引入该界面层以后,多孔铝的阻尼能力有了非常显著的提高,甚至有了量级的变化.分析表明,借助界面层的微小滑移而耗能应该是阻尼能力提高的主要机制.同时也意味着利用有机高分子设计界面层从而提高相应多孔材料的阻尼能力是可行的、高效的.     

原子层沉积与聚焦离子束切片法制备X射线波带片

针对X射线波带片对大高宽比的应用需求,采用原子层沉积法在光滑的金属丝表面生长膜厚可高精度控制的多层膜环带结构,再利用聚焦离子束切片技术获得大高宽比的多层膜X射线波带片。采用复振幅叠加法设计了以Al₂O₃/HfO₂分别为明环和暗环材料的X射线波带片,实验上利用原子层沉积在直径为72μm的金丝表面交替沉积了10.11μm的Al₂O₃/HfO₂多层膜,环带数为356,总直径为92.22μm,最外环宽度为25 nm。通过聚焦离子束切割得到高为1.08μm、高宽比达43∶1的X射线多层膜菲涅耳波带片。该波带片应用于上海光源(BL08U1A)软X射线成像线站时,在1.2 keV X射线下实现聚焦成像功能,展现出利用该技术制备多层膜X射线波带片的潜力。     

飞秒激光用多层介质膜脉宽压缩光栅的设计

以薄膜光学的干涉理论和衍射光学的傅里叶模式理论为基础，给出了0.8μm飞秒激光器用多层介质膜脉宽压缩光栅的理论设计；设计采用H3L(HL)^9H0.5L2.4H的多层介质膜为基底，当刻蚀后表面浮雕结构的占宽比为0.35，线密度为1480线/mm，槽深为0.2μm，顶层HfO₂的剩余厚度为0.15μm时，对于Littrow角度(36.7°)和TE波模式入射的衍射光栅其-1级衍射效率达到95％以上. 关键词： 飞秒激光 脉宽压缩光栅 多层介质膜     

硫化锌基底硬质红外保护薄膜技术研究

硫化锌在3~5μm和7.7~9.3μm两个波段具有较高透过率,但其脆性大、耐摩擦性能较差,在其表面镀制类金刚石膜保护膜可显著提高其使用性能。直接在硫化锌基底沉积类金刚石膜难以实现,采用匹配层与过渡层的设计思想,制备出类金刚石膜与硫化锌基底之间相互牢固结合的过渡层。通过等离子体化学气相增强法在过渡层上成功制备类金刚石膜。研究了射频功率、气压等对保护膜系力学性能的影响。结果表明,镀制了硬质保护薄膜的硫化锌窗口在3~5μm和7.7~9.3μm双波段的平均透过率均高于90%,膜层硬度为硫化锌窗口近5倍。经环境试验之后,膜层光学性能与机械性能均无变化。     

Effects on the field emission properties by variation in surface morphology of patterned photosensitive carbon nanotube paste using organic solvent

Photosensitive carbon nanotube (CNT) paste was prepared by 3-roll milling of multi-walled carbon nanotubes (MWNTs), UV-sensitive binder solution, and Ag as filler additives. Arrays of MWNT dots with a diode structure were fabricated by a combination of screen printing method and photolithography using these paste, and acetone utilized as the developer. The MWNT dots were well-defined and the organic binder materials in the dots were partially removed. The MWNT film without a heat treatment showed a high current density of 1.35 mA/cm² at 3.25 V/μm and low turn-on field of 2.2 V/μm at 100 μA/cm². Acetone can be used as an efficient developer to form patterns and to remove the organic residues in patterns, simultaneously.     

Effect of temperature on residual stress and mechanical properties of Ti films prepared by both ion implantation and ion beam assisted deposition

Ti films with a thickness of 1.6 μm (group A) and 4.6 μm (group B) were prepared on surface of silicon crystal by metal vapor vacuum arc (MEVVA) ion implantation combined with ion beam assisted deposition (IBAD). Different anneal temperatures ranging from 100 to 500 °C were used to investigate effect of temperature on residual stress and mechanical properties of the Ti films. X-ray diffraction (XRD) was used to measure residual stress of the Ti films. The morphology, depth profile, roughness, nanohardness, and modulus of the Ti films were measured by scanning electron microscopy (SEM), scanning Auger nanoprobe (SAN), atomic force microscopy (AFM), and nanoindentation, respectively. The experimental results suggest that residual stress was sensitive to film thickness and anneal temperature. The critical temperatures of the sample groups A and B that residual stress changed from compressive to tensile were 404 and 428 °C, respectively. The mean surface roughness and grain size of the annealed Ti films increased with increasing anneal temperature. The values of nanohardness and modulus of the Ti films reached their maximum values near the surface, then, reached corresponding values with increasing depth of the indentation. The mechanism of stress relaxation of the Ti films is discussed in terms of re-crystallization and difference of coefficient of thermal expansion between Ti film and Si substrate.     

Application of printed nanocrystalline diamond film for electron emission cathode

The low-cost and large area screen-printed nano-diamond film (NDF) for electronic emission was fabricated. The edges and corners of nanocrystalline diamond are natural field-emitters. The nano-diamond paste for screen-printing was fabricated of mixing nano-graphite and other inorganic or organic vehicles. Through enough disperse in isopropyl alcohol by ultrasonic nano-diamond paste was screen-printed on the substrates to form NDF. SEM images showed that the surface morphology of NDF was improved, and the nano-diamond emitters were exposed from NDF through the special thermal-sintering technique and post-treatment process. The field emission characteristics of NDF were measured under all conditions with 10⁻⁶ Pa pressure. The results indicated that the field emission stability and emission uniformity of NDF were improved through hydrogen plasma post-treatment process. The turn-on field decreased from 1.60 V/μm to 1.25 V/μm. The screen-printed NDF can be applied to the displays electronic emission cathode for low-cost outdoor in large area.     

Influence of surface topography and pore architecture of alkali-treated titanium on in vitro apatite deposition

Alkali-treated titanium surfaces have earlier shown to induce bone-like apatite deposition. In the present study, the effect of surface topography of two-dimensional and pore architecture of three-dimensional alkali-treated titanium substrates on the in vitro bioactivity was investigated. Titanium plates with a surface roughness of R_a = 0.13 μm, 0.56 μm, 0.83 μm, and 3.63 μm were prepared by Al₂O₃ grit-blasting. Simple tetragonal and face-centered Ti6Al4V scaffolds with spatial gaps of 450-1100 μm and 200-700 μm, respectively, were fabricated by a three-dimensional fiber deposition (3DFD) technique. After alkali treatment, the titanium plates with a surface roughness of R_a = 0.56 μm were completely covered with hydroxyapatite globules after 7 days in simulated body fluid (SBF), while the coverage of the samples with other surface roughness values remained incomplete. Similarly, face-centered Ti₆Al₄ scaffolds with spatial gaps of 200-700 μm exhibited a full surface coverage after 21 days in SBF, while simple tetragonal scaffolds with spatial gaps of 450-1100 μm were only covered for 45-65%. This indicates the importance of surface topography and pore architecture for in vitro bioactivity.     

纳米氧化铈的制备及其抛光性能的研究

采用溶胶-凝胶法制备了纳米CeO2粉体,并采用XRD、TOF-SIMS对其进行了表征。结果表明平均晶粒度在13.3nm,粒度分布均匀。进而研究了纳米CeO2在玻璃基片抛光中的抛光性能。ZYGO形貌仪表明,抛光后其表面平均粗糙度值(Ra)可降低到0.6nm左右。原子力显微镜(AFM)在5μm×5μm范围内测得基片表面粗糙度Ra值为0.281nm,表面光滑,划痕等表面微观缺陷明显改善。     

Spectral emissivity of type E235B low carbon structural steel with different roughnesses

A self-built experimental apparatus was employed to study the spectral emissivity of type E235B low carbon structural steel in the wavelength range 2–15 μm at different temperatures by energy comparison method. The surface roughness and topography of the steel E235B were determined by a roughness tester and a scanning electron microscopy, respectively. And then, the spectral emissivity of steel E235B with six different roughnesses was measured before and after oxidation. The measurement results showed that the spectral emissivity increased with the increasing temperature and surface roughness before oxidation. The effect of roughness on the spectral emissivity is different at different wavelength and temperature ranges. However, the oscillatory behavior of the spectral emissivity was observed after oxidation. To explore the possible reasons for emissivity variation, the changes of surface roughness and optical roughness were investigated after oxidation. It is found that both the surface roughness and optical roughness increased after oxidation. Although the optical roughness can be used as one of the parameters to evaluate the effect of surface roughness on the spectral emissivity, it is insufficient to describe the effect of surface morphology on the spectral emissivity.     

Surface roughness measurement by speckle contrast under the illumination of light with arbitrary spectral profile

Quantification of surface roughness greater than a micron is desirable for many industrial and biomedical applications. Polychromatic speckle contrast has been shown theoretically to be able to detect such roughness range using an appropriate light source with a Gaussian spectral shape. In this paper, we extend the theory to arbitrary spectral profile by formulating speckle contrast as a function of spectral profile, surface roughness, and the geometry of speckle formation. Under a far-field set-up, the formulation can be simplified and a calibration curve for contrast and roughness can be calculated. We demonstrated the technique using a blue diode laser with a set of 20 metal surface roughness standards in the range 1–73 μm, and found that the method worked well with both Gaussian and non-Gaussian surfaces.     

Paper coatings with multi-scale roughness evaluated at different sampling sizes

Papers have a complex hierarchical structure and the end-user functionalities such as hydrophobicity are controlled by a finishing layer. The application of an organic nanoparticle coating and drying of the aqueous dispersion results in an unique surface morphology with microscale domains that are internally patterned with nanoparticles. Better understanding of the multi-scale surface roughness patterns is obtained by monitoring the topography with non-contact profilometry (NCP) and atomic force microscopy (AFM) at different sampling areas ranging from 2000 μm × 2000 μm to 0.5 μm × 0.5 μm. The statistical roughness parameters are uniquely related to each other over the different measuring techniques and sampling sizes, as they are purely statistically determined. However, they cannot be directly extrapolated over the different sampling areas as they represent transitions at the nano-, micro-to-nano and microscale level. Therefore, the spatial roughness parameters including the correlation length and the specific frequency bandwidth should be taken into account for each measurement, which both allow for direct correlation of roughness data at different sampling sizes.     

Characterisation of pavement profile heights using accelerometer readings and a combinatorial optimisation technique

Pavement surface profiles induce dynamic ride responses in vehicles which can potentially be used to classify road surface roughness. A novel method is proposed for the characterisation of pavement roughness through an analysis of vehicle accelerations. A combinatorial optimisation technique is applied to the determination of pavement profile heights based on measured accelerations at and above the vehicle axle. Such an approach, using low-cost inertial sensors, would provide an inexpensive alternative to the costly laser-based profile measurement vehicles. The concept is numerically validated using a half-car roll dynamic model to infer measurements of road profiles in both the left and right wheel paths.     

Preparation and in vitro characterization of aerosol-deposited hydroxyapatite coatings with different surface roughnesses

Hydroxyapatite (HA) coatings with different surface roughnesses were deposited on a Ti substrate via aerosol deposition (AD). The effect of the surface roughness on the cellular response to the coating was investigated. The surface roughness was controlled by manipulating the particle size distribution of the raw powder used for deposition and by varying the coating thickness. The coatings obtained from the 1100 °C-heated powder exhibited relatively smooth surfaces, whereas those fabricated using the 1050 °C-heated powder had network-structured rough surfaces with large surface areas and were superior in terms of their adhesion strengths and in vitro cell responses. The surface roughness (R_a) values of the coatings fabricated using the 1050 °C-heated powder increased from approximately 0.65 to 1.03 μm as the coating thickness increased to 10 μm. The coatings with a rough surface had good adhesion to the Ti substrate, exhibiting high adhesion strengths ranging from 37.6 to 29.5 MPa, depending on the coating thickness. The optimum biological performance was observed for the 5 μm-thick HA coating with an intermediate surface roughness value of 0.82 μm.