Preparation of novel CdS-graphene/TiO2 composites with high photocatalytic activity for methylene blue dye under visible light

In this study, CdS combined graphene/TiO₂ (CdS-graphene/TiO₂) composites were prepared by a sol–gel method to improve on the photocatalytic performance of TiO₂. These composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and transmission electron microscopy (TEM). The photocatalytic activities were examined by the degradation of methylene blue (MB) under visible light irradiation. The photodegradation rate of MB under visible light irradiation reached 90·1% during 150 min. The kinetics of MB degradation were plotted alongside the values calculated from the Langmuir–Hinshelwood equation. 0·1 CGT sample showed the best photocatalytic activity, which was attributed to a cooperative reaction between the increase of photo-absorption effect by graphene and photocatalytic effect by CdS.     

二维和三维微/纳高效精密加工中的纳立体刻印工艺

双光子聚合（TPP）是通过光敏剂中的非线性双光子吸收过程所引发的,其作为一种新工艺,自问世以来,已在二维和三维加工聚合应用领域中得到广泛研究．对于二维纳米图案的加工,纳复制工艺已经演变为体素模板扫描方法．该方法用黑白双色2块图作为设计图案,并转排成体素模板以控制聚焦激光素的开关．复杂的三维微结构也可以采用多重断面分层叠加的方法进行加工,各断面的扫描数据从三维CAD数据中得到．在聚合反应后,没有固化的液态树脂,其采用在树脂上浇注类似于酒精之类溶剂的方法去除,从而显露出聚合的微结构．在前期的工作中,已经成功地加工出了高空间分辨力的三维微光学器件,分辨力约为100nm．微机械器件和光子晶体等的近期研究工作提高了其TPP的效率和精度．介绍了近来开发的基于TPP的一些微加工工艺．     

Effects of the integrity of silicon thin films on the electrical characteristics of thin dielectric ONO film

Capacitors with two kinds of lower electrodes were fabricated and their effects evaluated on the electrical characteristics of oxide–nitride–oxide (ONO) film. One of the electrodes was made of amorphous silicon film chemically deposited using a gas mixture of Si2H6–PH3; the other was made of poly-Si film deposited by SiH4 decomposition and doped by As+ ion implantation. The ONO thin dielectric layer was composed of natural oxide, CVD silicon nitride and thermal oxide formed on the silicon nitride. The capacitance, the leakage current, the dielectric breakdown field and the time-dependent dielectric breakdown (TDDB) were tested to evaluate the electrical properties of the capacitors. The leakage current and the dielectric breakdown voltage showed similar values between the two capacitors, whereas the TDDB under negative bias showed a great difference. This indicates that, with respect to electrical properties, the integrity of the oxide grown on the in situ P-doped amorphous silicon is better than the oxide grown on the As+ ion-implanted poly-Si. What is more, phosphorus in the amorphous silicon did not lead to any problems with junction depth, even after post heat treatment at 950°C. This revised version was published online in July 2006 with corrections to the Cover Date.     

Growth of copper thin films on sputtered-TiN surfaces by metallorganic chemical vapour deposition from (hfac)Cu(I)(VTMS)

Copper (Cu) films were deposited on sputtered TiN with metallorganic chemical vapour deposition (MOCVD) from (hexafluoroacetylacetonate) Cu^(I) (vinyltrimethylsilane) [(hfac)Cu^(I)(VTMS)] at substrate temperatures of 100–300°C, total pressures of 10–2000 mtorr (1–300 Pa) and bubbler temperature of 50°C with Ar carrier gas. Cu was deposited in the form of discontinuous islands up to the film thickness of about 100 nm on the TiN substrate. The orientation of growing films was changed from random orientation to 〈1 1 1〉 with increasing deposition time and temperature. Increasing temperature increased the surface roughness of the film, and grain coalescence. Resistivity was increased due to the carbon incorporation from the thermal decomposition of Cu precursor. This revised version was published online in July 2006 with corrections to the Cover Date.     

温度变化下复合材料层合板的试验模态分析

通过动力测试试验研究了环境条件变化对复合材料层合板振动特性的影响 , 这对于复合材料结构基于动力响应健康监测和振动控制系统设计使用的安全性具有重要意义。在不同温度条件下利用锤击以及激振器实验方法测定复合材料层合板的动力响应 , 采用随机子空间法 (SSI) 识别了其固有频率、 阻尼以及模态振型。研究结果表明 , 复合材料层合板结构固有频率及阻尼比与温度变化存在逆相关关系 , 而所识别的模态振型变化并没有非常清晰的相关关系。分析结果进一步表明 , 复合材料结构振动控制和健康监测系统设计过程中需要考虑上述影响。