Site‐specific dual ink dip pen nanolithography™

The ability to deposit different materials with nanoscale precision at user‐specified locations is a very important attribute of dip pen nanolithography (DPN^®). However, the potential of DPN goes beyond simple deposition since DPN used in conjunction with lateral force microscopy (LFM) allows site‐specific investigations of nanoscale properties. In this work, we use two different inks, 16‐mercaptohexadecanoic acid (MHA) and 1‐octadecanethiol (ODT) to show site‐specific dual ink DPN enabled exclusively by our proprietary software. A diamond‐dot pattern was created by using a layer‐to‐layer alignment (LLA) algorithm, which enables a MHA pattern (diamond) to be written concentric with another ODT (central dot) pattern. This simple demonstration of multi‐ink DPN is not specific to alkanethiol ink systems, but is also applicable to other multi‐material patterning, interaction, and exchange studies. SCANNING 31: 122–126, 2009. © 2009 Wiley Periodicals, Inc.     

A small-angle X-ray scattering study of microphase separation transition of polyurethanes: Effect of hard segments

Three segmented polyurethane block copolymers PU-M, PU-X and PU-T containing different diisocynates, diphenylmethane-4,4'-diisocyanate (MDI), xylene diisocyanate (XDI) and 2,4-toluene diisocyanate (TDI) respectively with the same chain extender 1,4-butanediol (BD) and soft segment polyester-diol were investigated by small-angle X-ray scattering (SAXS). Microphase separation transition (MST) occurred due to the thermodynamic incompatibility between the soft and hard segments. The long domain spacing, interfacial thickness (or transition layer thickness), core zone, and lamellar thickness were determined for these three different polyurethanes from one dimension correlation function after the Fourier transformation of small-angle X-ray scattered intensity curve based on the Strobl and Schneider model. The structural parameters for these three polyurethanes determined from the scattering measurements indicate that the degrees of microphase separation are in the following sequence: PU-M > PU-X > PU-T.     

面向互联网新闻的在线话题检测算法

针对互联网新闻报道冗余多、议题发散、易漂移等特点,提出一种面向互联网的在线话题检测算法。该算法针对冗余问题提出子话题概念,针对议题发散问题建立双层检测结构,针对话题漂移问题提出基于滑动窗口的跟踪策略。应用该算法建立网上话题检测系统,通过来源于互联网的真实数据进行测试。结果表明,算法性能优于传统的单路径聚类算法,其最小错误代价率低于0．14。     

基于OpenDWG Toolkit访问AutoCAD DWG图形文件

本文介绍了AutoCAD DWG图形文件结构，针对其复杂的数据格式提供了一种基于OpenDWG Teolkit直接访问DWG图形文件的方法并给出了部分C 实现代码。     

A numerical comparison of precipitating turbulent flows between large‐eddy simulation and one‐dimensional turbulence

This study presents the results of computational fluid dynamics simulations of a multiphase, reacting, turbulent mixing layer in an idealized geometry. The purpose is to compare large‐eddy simulation (LES) to one‐dimensional turbulence (ODT) and examine the trends of the flow under differing mixing conditions. Aqueous streams are mixed together to precipitate polymorphs of calcium carbonate. The polymorphs of calcium carbonate are tracked numerically using population balance equations (PBE). Each PBE contains all of the relevant physical models to track the particle evolution including nucleation, growth, and aggregation. A simple subgrid mixing model that is convenient for use with PBEs was implemented in the LES code. The higher spatial resolution achievable with ODT allowed an investigation on the effect of resolution on the mixing‐model error. The Reynolds number of the flow is varied and is shown to cause a decrease in average particle sizes with higher mixing rates. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3185–3197, 2015     

Advances in piezoelectric thin films for acoustic biosensors,acoustofluidics and lab-on-chip applications

Recently, piezoelectric thin films including zinc oxide (ZnO) and aluminium nitride (AlN) have found a broad range of lab-on-chip applications such as biosensing, particle/cell concentrating, sorting/patterning, pumping, mixing, nebulisation and jetting. Integrated acoustic wave sensing/microfluidic devices have been fabricated by depositing these piezoelectric films onto a number of substrates such as silicon, ceramics, diamond, quartz, glass, and more recently also polymer, metallic foils and bendable glass/silicon for making flexible devices. Such thin film acoustic wave devices have great potential for implementing integrated, disposable, or bendable/flexible lab-on-a-chip devices into various sensing and actuating applications. This paper discusses the recent development in engineering high performance piezoelectric thin films, and highlights the critical issues such as film deposition, MEMS processing techniques, control of deposition/processing parametres, film texture, doping, dispersion effects, film stress, multilayer design, electrode materials/designs and substrate selections. Finally, advances in using thin film devices for lab-on-chip applications are summarised and future development trends are identified.     

Selecting the optimal linear alcohol ethoxylate for enhanced oily soil removal

Use of nonionic surfactants in detergent products has become increasingly popular because of their tolerance to hardness ions and their effect on lowering the critical micelle concentration of anionics. Their performance as detergents, however, is very sensitive to changes in temperature and electrolyte concentration, which need to be carefully controlled in order to ensure that phase inversion conditions prevail. For a fixed temperature in an application, the only variables available for optimizing the performance of a system containing nonionics are: the type of nonionic, and the concentrations of electrolytes and anionics. Based on the mutual interactions of these ingredients in mixed systems, we have devised some guidelines for selection of the optimal ethylene oxide (FO) chain length in lauryl alcohol ethoxylate type of nonionics for a range of electrolytes and anionic surfactant concentrations. For any given concentration of electrolytes (sodium carbonate and sodium tripolyphosphate), anionic (sodium linear alkyl benzene sulfonate) and nonionic, the detergency of synthetic sebum from blended polyester/cotton fabrics shows a maximum as a function of average FO moles in the nonionic. Oil/water interfacial tension shows an expected reverse trend. The optimal EO moles (for maximal detergency) show a monotonically increasing trend when plotted as a function of the ratio of nonionic to anionic concentration for a fixed level of electrolyte. The optimal EO moles also increase with increasing level of electrolytes in the system. However, the effect of nonionic/anionic ratio is much stronger than the effect of electrolytes on the optimal EO moles.     

Measuring detergency of oily soils in the vicinity of phase inversion temperatures of commercial nonionic surfactants using an oil-soluble dye

We have used a simple technique to measure the detergency of model oily soil from 63∶35 blended polyester/cotton fabrics using solutions of commercial linear lauryl alcohol ethoxylates in the vicinity of their phase inversion temperatures (PIT). The method involves incorporation of an oil-soluble dye in the oily soil, and measurement of reflectance at an appropriate wavelength directly on the fabric before and after wash. This technique was validated for our systems, and it provides an additional visual cue for the efficiency of soil removal. Hexadecane, which represents the linear hydrocarbon part of sebum (typical soil encountered in detergency) and has been widely studied in the literature, was used as the model oily soil. Maximal detergency occurs as a function of washing temperature at approximately 35, 62, and 80°C for ethoxylates with four, five, and six moles of ethylene oxide (C₁₂EO₄, C₁₂EO₅, and C₁₂EO₆), respectively. The oil/water interfacial tension, measured using the spinning drop method, exhibits corresponding minima and complements the detergency results. Addition of sodium carbonate, a salting-out electrolyte, decreases the optimal detergency temperature (ODT) of C₁₂EO₅, shifting its behavior toward C₁₂FO₄ whereas addition of anionic surfactant increases the ODT of C₁₂FO₅, mimicking the behavior of a higher ethoxylate.     

产品设计BOM的自动生成方法及关键技术研究

提出了一种产品设计BOM的自动生成方法,利用OpenDWG联盟组织提供的OpenDWG Toolkit（以下简称ODT）技术从DWG文件中读取设计BOM所需要的信息,自动生成设计BOM产品结构树及其展开产品结构关系表。讨论了在设计BOM自动生成过程中所遇到的难点及相应的解决办法,实现了一个设计BOM自动生成系统并将之应用于企业实际生产管理中。