Two‐Dimensional Periodic Relief Gratings as a Versatile Platform for Label‐Free Specific DNA Detection

In this study, nanopillar arrays of silicon oxide are fabricated through a process involving very‐large‐scale integration, for use as two‐dimensional periodic relief gratings (2DPRGs) on silicon surfaces. Oligonucleotides are successively immobilized on the pillar surface, allowing the system to be used as an optical detector specific for the targeted single‐stranded DNAs (ssDNAs). The surfaces of the oligonucleotides‐modified 2DPRGs undergo insignificant structural changes, but upon hybridizing with target ssDNA, the 2DPRGs undergo dramatic changes in terms of their pillar scale. Binding of the oligonucleotides to the 2DPRG occurs in a way that allows them to retain their function and selectively bind the target ssDNA. The performance of the sensor is evaluated by capturing the target ssDNA on the 2DPRGs and measuring the effective refractive index (n_eff). The binding of the target ssDNA species to the 2DPRGs results in a color change from pure blue to red, observable by the naked eye along an angle of 15–20°. Moreover, effective medium theory is used to calculate the filling factors inside the 2DPRGs and, thereby, examine the values of n_eff during the structural changes of the 2DPRGs. Accordingly, these new films have potential applications as label‐free optical biosensors.     

Developing a four‐layer system rutting model in highway

Abstract

A four‐layer rutting model was developed to account for material property changes in the progression of accumulated compressive plastic strains in all roadway layers on the basis of traffic passing in this study. This paper demonstrates that incorporating the mechanistic‐empirical approach in the prediction of rutting provides value information on the contribution of each layer to rutting in flexible pavements.     

Influence of injection velocity and joint geometry on quality of insert molding

A study of the influence of the injection velocity and the joint geometry on the quality of insert molding is presented. The proposed approach was based on the rheological concept, and the optimal injection velocity of insert molding was determined through calculations of the relative viscosity with corresponding injection velocities. In addition, the influence of the joint geometry between two different materials on the adhesion performance was also evaluated experimentally. A newly designed wafer cassette storage box that consisted of a cover (polybutylene terephthalate) with a transparent window (polycarbonate) and a base was given to demonstrate how to implement the methodology. Besides injection velocity, this study shows that the joint geometry is also a significant factor in improving the adhesion strength between the cover and the transparent window.POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers     

Exergeo-economic performance bound and optimisation criteria for heat engines

Finite-time thermodynamics and exergeoeconomics are combined to form a new analysis method called finite-time exergeoeconomics in this paper. The optimal thermal efficiency and profit rate holographic spectrum for the heat engine is derived. The derivation is used to obtain the efficiency bound at maximum profit rate and the optimisation criteria for selecting thermodynamic parameters of the heat engine cycles. The results provide a solid theoretical basis for design and evaluation of practice heat engines.     

Optimal performance for a steady-flow endoreversible refrigerator model including five typical cycles

The optimal performance of a universal endoreversible steady-flow refrigerator cycle consisting of a constant thermal-capacity heating branch, a constant thermal-capacity cooling branch and two adiabatic branches with heat transfer loss was analysed using finite-time thermodynamics. The analytical formulae about cooling load, coefficient of performance, exergy loss rate, exergy output rate and ecological criterion of the endoreversible steady-flow refrigerator cycle are derived. Moreover, analysis and optimisation of the model were carried out in order to investigate the effect of the cycle process on the performance of the cycles using numerical examples. The results obtained include the performance characteristics of endoreversible steady-flow Carnot, Diesel, Otto, Atkinson and Brayton refrigeration cycles. The results can provide some theoretical guidance for the design of practical refrigerators.     

Specific interactions in miscible polymer blends of poly(2‐hydroxypropyl methacrylate) with polyvinylpyrrolidone

The miscibility behaviour and hydrogen‐bonding interaction in blends of poly(2‐hydroxypropyl methacrylate) (PHPMA) with polyvinylpyrrolidone (PVP) were characterized using differential scanning calorimetry and Fourier‐transform infrared spectra. This polymer blend was miscible over the whole composition range and an unusually large positive deviation of T_g from the linearity rule was observed, indicating strong hydrogen bonding between the hydroxyl group of PHPMA and the carbonyl group of PVP. Infrared spectroscopic analysis provided positive evidence for the intra‐molecular hydrogen bonding of PHPMA and inter‐molecular hydrogen bonding between PHPMA and PVP at various compositions and temperatures. Furthermore, equilibrium constants and enthalpies of self‐association and inter‐association between functional groups in the blend of PHPMA and PVP were calculated to explain the results. Copyright © 2004 Society of Chemical Industry