Slip behavior in polymethylmethacrylate films in dependence of self-assembled monolayer wettability

The slip behavior of polymethylmethacrylate (PMMA) films prepared on self-assembled monolayers (SAM) supported by Si substrate was investigated according to the wettability of the SAM. To this end, the dewetting of thermally annealed PMMA films was measured varying the surface energies of underlyed SAM. Total surface energy (γ^t) of SAM increased with increasing UV exposure time. At surface energy of <31.3 mJ/m², the PMMA films showed slip behavior; radius of holes (R) ∝ t^0.68−0.72, where t is dewetting time. The slip behavior seems to be dominated by the viscous friction between the PMMA films and the SAM. As t increased, slip behavior disappeared, R ∝ t^0.34−0.39. At surface energy of >42.0 mJ/m², the PMMA films did not show slip behavior, R ∝ t^0.45. It means that interface effects between PMMA films and SAM layers increase with increasing of γ of SAM layers, and then the molecular interaction in the PMMA films increases. The spreading coefficient (S) of the PMMA films approached positive number for UV exposure times between 0 s and 300 s. We concluded that the stability of the PMMA films can be simply controlled by UV-ozone treatment on the SAM layers.     

红外方式数字图像采集报警系统的设计

介绍了AT91SAM7S64单片机的主要特点和性能,分析了采用该芯片减少及优化外围电路,提高精度、实时性和可靠性等方面的优势.着重阐述了应用该芯片实现红外控制、自动摄像的软、硬件设计方案,分析了为提高实时性而在软硬件设计方面所采取的措施.     

高速下载COS的双界面智能卡读卡器设计

为了提高智能卡的发卡效率,本文设计了一套可以调节接触式通信速率的双界面智能卡读卡器,并且通过提高传输速率、增加传输数据的长度以及使用pipeline的结构两张卡同发的方法来提高智能卡发卡的效率,在实际应用中提升了中小型智能卡厂商的发卡效率。     

The synthesis and antiwear action of tungsten dithiolate

Tungsten dithiolate was synthesised by the reaction of WO₃ with toluene-3,4-dithiol (abbreviated to H₂TDT), and its extreme-pressure and antiwear properties were investigated on a four-ball tester. The results showed that it possesses fairly good extreme-pressure and antiwear abilities. Based on analytical results obtained by Scanning Auger Microprobe and Scanning Electron Microscopy, as well as Electron Ionisation Mass Spectra fragments, the antiwear mechanism of WTDT suggested that a permeating layer containing WC, WS₂, and WO₃ played an important role in the antiwear and friction-reducing action.     

SAM AND XPS STUDIES ON SURFACE SEGREGATION OF SUBSTRATE ELEMENTS IN Au-Ni-KOVAR ALLOY SYSTEM

The surface segregation of substrate elements through the Au layer in the Au-Ni-Kovar sys- tem specimens heated at 250—350℃ for 0.5—1.5 h has been studied by SAM and XPS. Visual evidence of the mechanism for Ni and Co surface segregation of the complicated sys- tem has been given,i.e.Ni and Co penetrated the gold layer mainly by grain boundary diffu- sion and then covered the Au layer by surface diffusion.The strdy results of the chemical states of surface segregation elements not only indicate that oxygen adsorption and oxidation reaction are the driving force for the surface segregation of Ni and Co,but also show that the above segregation can result in water absorption on surfaces.     

Conformal electroless deposition of Cu seed layer on a 60-nm trench pattern modified with a self-assembled monolayer

We have developed a novel activation technique for the conformal electroless deposition (ELD) of Cu on a SiO₂ substrate modified with an organic self-assembled monolayer. The SiO₂ substrate was modified with amine groups using 3-aminopropyltriethoxysilane and Au nanoparticles (AuNPs) to form a uniform, continuous catalyst for ELD. The Au catalytic layer formed on the amine-SiO₂ substrate was stabilized by electrostatic interactions between the positively charged protonated-amine self-assembled monolayer (SAM) and negatively charged AuNPs. Cu films were then electrolessly deposited on Au-catalyzed SiO₂ substrates. The Cu seed layer formed by this method showed a highly conformal and continuous structure. Cu electrodeposition on the 60-nm trench was demonstrated using an acid cupric sulfate electrolyte containing chloride, polyethylene glycol 4000 and bis(3-sulfopropyl)disulfide. The resulting electroplated Cu showed excellent filling capability and no voids or other defects were observed in a 60-nm trench pattern.     

Electrochemical characterization of a 1,8-octanedithiol self-assembled monolayer (ODT-SAM) on a Au(1 1 1) single crystal electrode

Recently, it has becoming increasingly important to control the organization of self-assembled monolayers (SAMs) of ω-functionalized thiols for its potential applications in the construction of more complex molecular architectures. In this paper, we report on the spontaneous formation of a SAM of octanedithiol (ODT) as a function of the modification time. Electrochemical techniques such as cyclic voltammetry, double layer capacitance and electrochemical impedance spectroscopy are used for the characterization of this monolayer. The increase in modification time brings about changes in the octanedithiol self-assembled monolayer (ODT-SAM) reductive desorption voltammograms that indicate an evolution toward a more ordered and compact monolayer. This trend has also been found by following the changes in the electron transfer processes of the redox probe K₃Fe(CN)₆. In fact, the ODT-SAM formed at low-modification time does not significantly perturb the electrochemical response as it is typical of either a low coverage or of the presence of large defects in the layer. Upon increasing the modification time, the voltammograms of the redox probe adopt a sigmoidal shape indicating the existence of pinholes in the monolayer distributed as an array of microelectrodes. The surface coverage as well as the size and distribution of these pinholes have been determined by the impedance technique that gives a more reliable evaluation of these monolayer structural parameters.     

Can ITIL contribute to IT/business alignment? An initial investigation

Strategic alignment has been viewed as one of the main concerns of management and IT executives. Organizations have realized that in order to achieve competitive advantage, IT needs to be strategically aligned with business objectives. Strategic alignment enables organizations to choose IT applications that meet their needs and as a result, to enhance their profitability and reduce costs. Despite the importance of this matter and a large body of literature written on this subject, it has not yet been identified how it can be successfully achieved and maintained. This paper attempts to provide insight on this matter by investigating an initiative called Information Technology Infrastructure Library (ITIL), which ensures the effective and efficient delivery of IT services. The intention of this research was to identify how effective ITIL was in improving alignment between IT and business objectives. The Strategic Alignment Model (SAM) developed by Henderson and Venkatraman was used for this research. This consists of four parts: IT strategy; business strategy; organizational infrastructure and processes; and IS infrastructure and processes. By placing ITIL in the internal domain of the model as a substitute for the IS infrastructure and processes it has been identified that it has the ability to impact the other three main areas of the model and as result enables alignment between all the four parts of model to be achieved. In addition to the above an empirical study has been conducted in order to further investigate the ability of ITIL in achieving alignment between IT and business objectives. Four participants have been interviewed from three organizations ranging from education and banking to the IT sector. The results of the research indicate that ITIL has potential as an effective approach in achieving alignment.     

Detection of delaminations in sub-wavelength thick multi-layered packages from the local temporal coherence of ultrasonic signals

Interface delamination caused by thermo-mechanical loading and mismatch of thermal coefficients is one of the important failure modes occurring in electronic packages, thus a threat for package reliability.Scanning acoustic microscopy is widely employed in the inspection of microelectronic devices. However, for advanced packaging formats such as LFBGA with flip-chip technology, whose boundaries dimensions are comparable to the acoustic wavelengths, ultrasonic echoes are often noisy and overlapped. Therefore, a more rigorous approach is required to detect anomalies, such as delaminations.A new signal processing methodology based on local temporal coherence is proposed to detect delaminations in sub-wavelength thick multi-layered packages.This work presents local temporal coherence analysis as a means of comparing two waveforms in order to provide a quantitative measure of the shape change of a signal compared to a reference as a function of time. Application of this procedure for delamination analysis in complex microelectronic packages is demonstrated.     

Influence of surface chemistry on inkjet printed carbon nanotube films

Carbon nanotube ink chemistry and the proper formulation are crucial for direct-write printing of nanotubes. Moreover, the correct surface chemistry of the self-assembled monolayers that assist the direct deposition of carbon nanotubes onto the substrate is equally important to preserve orientation of the printed carbon nanotubes. We report that the successful formulation of two single walled carbon nanotube (SWNT) inks yields a consistent, homogenous printing pattern possessing the requisite viscosities needed for flow through the microcapillary nozzles of the inkjet printer with fairly modest drying times. The addition of an aqueous sodium silicate allows for a reliable method for forming a uniform carbon nanotube network deposited directly onto unfunctionalized surfaces such as glass or quartz via inkjet deposition. Furthermore, this sodium silicate ingredient helps preserve applied orientation to the printed SWNT solution. Sheet resistivity of this carbon nanotube ink formula printed on quartz decreases as a function of passes and is independent of the substrate. SWNTs were successfully patterned on Au. This amine-based surface chemistry dramatically helps improve the isolation stabilization of the printed SWNTs as seen in the atomic force microscopy (AFM) image. Lastly, using our optimized SWNT ink formula and waveform parameters in the Fuji materials printer, we are able to directly write/print SWNTs into 2D patterns. Dried ink pattern expose and help orient roped carbon nanotubes that are suspended in ordered arrays across the cracks.