面向心血管应用的电子束蒸发氧化钛薄膜的特性——润湿性与血液相容性

用电子束蒸发的方法在钛盘上沉积氧化钛薄膜以检验其在心血管支架方面的应用.用接触角仪测定水滴在所制备氧化钛薄膜表面的接触角,随着沉积过程中氧气流量的增加,薄膜的接触角不断降低,经过热处理后薄膜的亲水性得到了增强.通过观察猪主动脉平滑肌细胞(PASMC)在样品表面的生长行为,研究薄膜的结构与细胞活性的关系.结果表明,覆有薄膜的钛盘具有更好的生物相容性,而沉积后的热处理能够进一步改善氧化钛薄膜的生物相容性.通过观察血小板的吸附行为研究薄膜的血液相容性,发现在所制备的氧化钛薄膜上吸附了极少的血小板.研究结果表明,用电子束蒸发制备的氧化钛薄膜能够用于心血管支架的表面改性.     

电弧离子镀沉积碳膜的结构和疏水性能

为了研究脉冲偏压对薄膜结构和疏水性能的影响,采用电弧离子镀技术在不锈钢和硅基底材料上沉积了纯碳薄膜,在保持直流偏压、频率和占空比等工艺参数稳定的情况下,在不同脉冲偏压下制备获得纯碳薄膜.分别利用X线衍射仪、X线光电子能谱、扫描电镜、摩擦磨损仪和接触角测量仪对薄膜样品的微观结构、表面形貌、摩擦系数和疏水性能进行测试.结果表明:沉积所得纯碳薄膜均呈非晶态,随着脉冲偏压的升高,纯碳薄膜表面形貌质量先变好再变坏;摩擦系数先变小后变大,但变化幅度不大;接触角先减小后增大.脉冲偏压为300 V时,样品表面形貌最平整,摩擦系数最小,为0.192;在脉冲偏压为500V时,纯碳薄膜样品的接触角平均值最大,为102.53°,疏水性能最好.     

玻璃基片上磁控溅射制备纳米TiO2薄膜的亲水性能研究

采用射频磁控溅射法制备了纳米TiO2薄膜,应用原子力显微镜观察了薄膜表面形貌,通过测量薄膜表面水滴直径计算接触角的方法研究了TiO2薄膜的亲水性能,发现磁控溅射制备的TiO2薄膜在紫外灯照射下有明显亲水性.     

钛合金表面稀土改性双层羧基化石墨烯复合薄膜的摩擦磨损性能

利用自组装成膜技术在钛合金基片表面制备了稀土改性双层羧基化石墨烯复合薄膜,采用接触角测量仪测量薄膜表面的接触角,采用扫描电子显微镜观察薄膜表面的微观形貌,并利用UMT-2MT型摩擦磨损试验机及原子力显微镜研究薄膜的宏观及微观摩擦磨损性能.结果表明:所制备的稀土离子改性双层羧基化石墨烯复合薄膜具有优异的摩擦磨损性能;相比于单层薄膜,稀土改性双层羧基化石墨烯复合薄膜具有更低的摩擦系数和微观摩擦力,表现出更优异的宏观及微观摩擦磨损性能.     

溶胶-凝胶法制备超疏水性OTS-SiO2复合薄膜

以正硅酸乙酯(TEOS)为先驱体,采用酸/碱两步溶胶-凝胶法和自组装技术制备了具有超疏水性的薄膜.利用红外光谱(FT-IR)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)和接触角仪等测试方法对十八烷基三氯硅烷(OTS)修饰前后薄膜的结构、形貌、表面元素组成与润湿等性能进行了表征和分析.结果表明,制备的OTS-SiO2复合薄膜具有良好的超疏水性能,水滴在该薄膜上的最大静态接触角为156°,滚动角小于5°.     

溶胶-凝胶法制备超疏水性OTS-SiO2复合薄膜

以正硅酸乙酯(TEOS)为先驱体,采用酸/碱两步溶胶-凝胶法和自组装技术制备了具有超疏水性的薄膜.利用红外光谱(FT-IR)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)和接触角仪等测试方法对十八烷基三氯硅烷(OTS)修饰前后薄膜的结构、形貌、表面元素组成与润湿等性能进行了表征和分析.结果表明,制备的OTS-SiO2复合薄膜具有良好的超疏水性能,水滴在该薄膜上的最大静态接触角为156°,滚动角小于5°.     

溅射压强对光伏玻璃表面二氧化钛自清洁薄膜润湿性的影响

主要研究了溅射压强对光伏玻璃表面二氧化钛自清洁薄膜润湿性的影响。采用射频磁控溅射法制备了具有自清洁功能的二氧化钛薄膜,通过调控溅射压强改变薄膜润湿性。研究发现:薄膜中Ti元素主要以Ti+4形式存在。当溅射压强由0.4 Pa增加到0.6 Pa时,二氧化钛薄膜表面粗糙度由1.02 nm降低到0.65 nm,薄膜的水接触角由68.9°小幅下降到67.9°,随着溅射压强增加到1.4 Pa,薄膜表面粗糙度又升高到2.38 nm,薄膜的水接触角持续增加到87.5°,二氧化钛薄膜表现出亲水性;薄膜表面粗糙度变化与水接触角变化表现出相同的变化趋势,粗糙度变化有利于调节二氧化钛薄膜表面润湿性。当溅射压强为0.6 Pa时,二氧化钛薄膜滚动角最小,达到5°,此时薄膜的水接触角为最小角67.9°,表面自由能最大,为34.3 mJ/m2,有利于减小固液间相对运动的阻力。     

稀土改性碳纳米管复合薄膜制备及其摩擦磨损性能

利用自组装技术,在玻璃基片表面制备了稀土改性碳纳米管复合薄膜,采用接触角测量仪测量了不同成膜时间下水在薄膜表面的接触角,使用X射线光电子能谱仪分析了薄膜表面稀土元素的化学状态,并运用UMT 2MT型摩擦磨损试验机评价了薄膜的摩擦磨损性能.结果表明：稀土改性后的碳纳米管成功地组装到磷酸化后的氨基硅烷薄膜表面而形成碳纳米管复合薄膜;碳纳米管复合薄膜表现出优异的摩擦磨损性能,在给定试验条件下,玻璃基片表面的摩擦系数由0.70降至0.13左右, 并表现出了优异的耐磨性和摩擦稳定性.     

射频磁控溅射制备CuAlO_2薄膜及性能表征

利用Al(OH)3和Cu2O高温固相反应烧结制备的靶材,采用射频磁控溅射法,在玻璃基片上制备非晶CuAlO2薄膜.薄膜的表面均匀,颗粒大小约为50 nm,可见光范围内透射率为60%,平均折射率达2.0,直接带隙为3.86 eV.随着在紫外光源下曝光时间的增加,薄膜的接触角从96.3°减小到87.5°,薄膜仍呈现出良好的疏水性.     

Ag~+注入对TiO_2薄膜光催化、抗菌和亲水性能的影响

为提高TiO2材料的光催化能力,采用匀胶法在载玻片上制备TiO2薄膜,通过离子注入技术在TiO2薄膜表面掺杂Ag+,离子注入时加速电压为40kV,注入剂量分别为5×1015、1×1016、3×1016、6×1016和1×1017ions/cm2.以甲基橙为降解物,研究了Ag+注入对TiO2薄膜紫外光作用下光催化效率的影响,并通过大肠杆菌在紫外光照射下的存活率考察了Ag/TiO2薄膜的抗菌效率.此外,利用接触角测量仪测量Ag/TiO2薄膜分别在避光和紫外光照射下水接触角的变化情况,研究了Ag+注入对TiO2薄膜亲水性的影响.实验结果表明:注入剂量为1×1016ions/cm2时,TiO2薄膜光催化效率最高,与未注入薄膜比较提高了约1.26倍.此外,适量的Ag+注入有利于TiO2薄膜抗菌效率的提高,并改善了薄膜的亲水性能,紫外光作用下,薄膜具有最佳抗菌性和亲水性时,Ag+的注入剂量为3×1016ions/cm2.     

Manipulation of atoms across a surface at room temperature

Since the realization that the tips of scanning probe microscopes can interact with atoms at surfaces, there has been much interest in the possibility of building or modifying nanostructures or molecules directly from single atoms. Individual large molecules can be positioned on surfaces, and atoms can be transferred controllably between the sample and probe tip. The most complex structures are produced at cryogenic temperatures by sliding atoms across a surface to chosen sites. But there are problems in manipulating atoms laterally at higher temperatures--atoms that are sufficiently well bound to a surface to be stable at higher temperatures require a stronger tip interaction to be moved. This situation differs significantly from the idealized weakly interacting tips of scanning tunnelling or atomic force microscopes. Here we demonstrate that precise positioning of atoms on a copper surface is possible at room temperature. The triggering mechanism for the atomic motion unexpectedly depends on the tunnelling current density, rather than the electric field or proximity of tip and surface.     

Biomimetic fabrication and characterization of an artificial rice leaf surface with anisotropic wetting

In nature,rice leaves exhibit special anisotropic sliding capabilities.Although researchers have succeeded in fabricating artificial rice leaf structures and realizing the wettability function of the leaf surface,these methods used to date are complex and do not allow the fabrication of surfaces with large area.Herein,we adopted a simple technology—two steps soft transfer to fabricate biomimetic rice leaf.The fabricated surface well reproduced the structures of the rice leaf surface and exhibited a static superhydrophobic property similar to that of the real rice leaf surface.In terms of its dynamic wettability,it clearly exhibited an anisotropic sliding property.Systematic measurements showed that the sliding angles parallel and perpendicular with the vein direction were 25° and 40°,respectively.The method was simple and reliable,without the need for expensive instruments and complex technologies,which could be used for the rapid fabrication of large-area artificial rice leaf surfaces.We believe that the artificial rice leaf surface fabricated by this method has great potential applications in biomimetic functional surfaces,microfluidics,and so on.     

流化床辐射换热机理研究

本文通过对高温流化床内辐射传热特点进行分析,提出了颗粒堆积多层反射模型.径与劣质煤流化床锅炉的实验结果相比较,证明该机理模型能有效地计算大颗粒流化床中的辐射分量.     

Reverse microemulsion synthesis of nanostructured complex oxides for catalytic combustion

Catalysts play an important role in many industrial processes, but their use in high-temperature applications-such as energy generation through natural gas combustion, steam reforming and the partial oxidation of hydrocarbons to produce feedstock chemicals--is problematic. The need for catalytic materials that remain stable and active over long periods at high operation temperatures, often in the presence of deactivating or even poisoning compounds, presents a challenge. For example, catalytic methane combustion, which generates power with reduced greenhouse-gas and nitrogen-oxide emissions, is limited by the availability of catalysts that are sufficiently active at low temperatures for start-up and are then able to sustain activity and mechanical integrity at flame temperatures as high as 1,300 degrees C. Here we use sol-gel processing in reverse microemulsions to produce discrete barium hexa-aluminate nanoparticles that display excellent methane combustion activity, owing to their high surface area, high thermal stability and the ultrahigh dispersion of cerium oxide on the their surfaces. Our synthesis method provides a general route to the production of a wide range of thermally stable nanostructured composite materials with large surface-to-volume ratios and an ultrahigh component dispersion that gives rise to synergistic chemical and electronic effects, thus paving the way to the development of catalysts suitable for high-temperature industrial applications.     

溅射含纳米锗氧化硅复合薄膜的光致发光和拉曼特性

采用射频磁控溅射法制备了含纳米锗的氧化硅复合薄膜，在室温下对不同温度退火的样品测量了光致发光谱，其发光峰位均位于580nm，通过对样品所作的拉曼散射光谱的拟合，确定出了样品中纳米锗的尺寸，并发现纳米锗的平均尺寸随温度退火的升高在增大。     

AlGaAs／GaAs单片集成激光发射机

报道一种新型ＡｌＧａＡｓ／ＧａＡｓ单片集成激光发射机。这种器件利用液相外延生长中的伴生高阻层，解决了半导体激光器与场效 晶体管驱动电路的工艺共容性问题，具有场效 晶体管与激光器结构同时形成且二者表面自动找平、制作简单的优点。     

Temperature dependence of niobium superconducting nanowire single-photon detectors in He-3 cryocooler

Performances of superconducting nanowire single-photon detectors （SNSPDs） based on low Tc mate- rials strongly depend on the operating temperatures. We have fabricated infrared-sensitive niobium SNSPDs based on doped niobium （Nb＊） films and measured them in He-3 cryocooler. The critical current approaches to the de-pair- ing current at 0.3 K. Therefore, with the decrease in tem- peratures, we have observed a monotonous increase of count rate at the wavelength of 1,521 nm and exponential decrease of dark count rate at all bias currents. The possible origin of dark counts for doped Nb devices is also discussed.     

Bio-replicated forming of the biomimetic drag-reducing surfaces in large area based on shark skin

On the investigation of biomimetic drag-reducing surface, direct replication of the firm scarfskins on low-resistance creatures to form biomimetic drag-reducing surfaces with relatively vivid morphology relative to the living prototype is a new attempt of the bio-replicated forming technology. Taking shark skin as the bio-replication template, the hot embossing method was applied to the micro-replication of its outward morphology. Furthermore, the skins were jointed together to form the drag-reducing surface in large area. The results of the resistance measurements in a water tunnel according to the flat-plate sample pieces have shown that the biomimetic shark-skin coating fabricated by the bio-replicated forming method has significant drag reduction effect, and that the drag reduction efficiency reached 8.25% in the test conditions.     

热处理对TiAl基合金喷丸试样组织与性能的影响

TiAl合金在高温下服役时,表面因受循环载荷而容易产生疲劳裂纹,因此有必要进行表面处理以改善其力学性能。使用直径0.2 mm钢丸在0.7 MPa气压下对TiAl合金进行室温喷丸实验,使用ABAQUS有限元分析软件进行喷丸仿真模拟研究。随后,对喷丸试样进行不同温度和保温时间的热处理。通过SEM观察TiAl合金纵截面的显微组织,使用X射线残余应力仪测量TiAl合金表面的残余压应力,使用显微硬度仪测量热处理后TiAl合金表面的显微硬度。结果发现,喷丸后TiAl合金表面出现许多凹坑和层片状突起,次表面处发生明显塑性变形并出现许多变形孪晶。热处理后TiAl合金表面残余压应力会随着保温时间的增加和热处理温度的升高而变小。硬度几乎表现出与残余应力相同的趋势,但当热处理温度为1 200℃时,因金相组织发生变化,α₂相含量明显增多,导致硬度增加。     

石墨烯薄膜的化学气相法制备及光、电特性研究

利用化学气相沉积方法制备了石墨烯薄膜,并研究了其光电特性。以乙醇做反应原料、氩气作为携载气体,在873 K、973 K、1 073 K的温度下合成石墨烯薄膜。应用光学显微镜观察,发现在1 073 K时能够制备大面积均匀、平整光滑的石墨烯薄膜。纳曼光谱分析结果表明:制备的石墨烯薄膜出现2 650 cm-1的石墨烯的特征峰-D强峰,同时该峰强度随温度的升高而迅速增强,说明低温不能使沉积的碳原子有效的石墨化为石墨烯,而较高的温度有助于乙醇分解并石墨化为石墨烯薄膜。在1 073 K时沉积的石墨烯薄膜具有良好的光、电特性,其电子迁移率可以达到104 cm2.(V.s)-1,光透射率达97%,因此,可用于制备石墨烯晶体管、太阳能电池等光电子器件。