Synthesis of UV-curable silane-coupling agent as an adhesion promoter

In color filter industry, a problem was found that the adhesion strength between glass substrate and black matrix was largely decreased after ITO sputtering process. In order to solve this problem, a new UV-curable silane-coupling agent (UV-SCA) was synthesized to be an adhesion promoter, which was synthesized by the reaction between the hydroxyl group of bisphenol A epoxy diacrylate and the isocyanate group of 3-(isocyanatopropyl)-triethoxysilane. The adhesion strength between glass substrate and black film, which was prepared from the carbon black photo-resist with or without the addition of UV-SCA, was determined by a tensile/compression strength tester, and the effect of UV-SCA on the adhesion strength before and after ITO sputtering process was also discussed.     

DNA molecule stretching through thermo-electrophoresis and thermal convection in a heated converging-diverging microchannel

A novel DNA molecule stretching technique is developed and tested herein. Through a heated converging-diverging microchannel, thermal convection and thermophoresis induced by regional heating are shown to significantly elongate single DNA molecules; they are visualized via a confocal laser scanning microscopy. In addition, electrophoretic stretching is also implemented to examine the hybrid effect on the conformation and dynamics of single DNA molecules. The physical properties of the DNA molecules are secured via experimental measurements.     

Hydrophilic polystyrene/maleic anhydride ultrafine fibrous membranes

Polystyrene/maleic anhydride (PSMA) was synthesized to reach a viscosity‐average molecular weight of 700 kDa and fabricated into ultrafine fibrous membranes consisting of fibers with an average diameter of 300 nm. These ultrafine PSMA fibers were rendered insoluble in organic solvents by reactions with hydrazine and ethylenediamine (ED). The highly efficient incorporation of diamines into the fibrous membranes was easily achieved by brief immersions in either dilute (0.5 wt %) hydrazine for 1 min or ED ether solution for 2 min. Heating at 150°C for 5 min produced crosslinked PSMA with very little or no solubility in acetone with the retention of the fibrous membrane structure. The ED‐crosslinked membranes were particularly stable to both bases and acids as well as hydrophilic solvents, had a 46° water contact angle, and absorbed 22 times the amount of water as the as‐spun fibrous membrane. This post‐fiber‐formation crosslinking approach was robust, highly efficient, and fast and required very little crosslinking reagent. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

A Bipolar Host Material Containing Triphenylamine and Diphenylphosphoryl‐Substituted Fluorene Units for Highly Efficient Blue Electrophosphorescence

Highly efficient blue electrophosphorescent organic light‐emitting diodes incorporating a bipolar host, 2,7‐bis(diphenylphosphoryl)‐9‐[4‐(N,N‐diphenylamino)phenyl]‐9‐phenylfluorene (POAPF), doped with a conventional blue triplet emitter, iridium(III) bis[(4,6‐difluoro‐phenyl)pyridinato‐N,C^2´]picolinate (FIrpic) are fabricated. The molecular architecture of POAPF features an electron‐donating (p‐type) triphenylamine group and an electron‐accepting (n‐type) 2,7‐bis(diphenyl‐phosphoryl)fluorene segment linked through the sp³‐hybridized C9 position of the fluorene unit. The lack of conjugation between these p‐ and n‐type groups endows POAPF with a triplet energy gap (E_T) of 2.75 eV, which is sufficiently high to confine the triplet excitons on the blue‐emitting guest. In addition, the built‐in bipolar functionality facilitates both electron and hole injection. As a result, a POAPF‐based device doped with 7 wt% FIrpic exhibits a very low turn‐on voltage (2.5 V) and high electroluminescence efficiencies (20.6% and 36.7 lm W^?1). Even at the practical brightnesses of 100 and 1000 cd m^?2, the efficiencies remain high (20.2%/33.8 lm W^?1 and 18.8%/24.3 lm W^?1, respectively), making POAPF a promising material for use in low‐power‐consumption devices for next‐generation flat‐panel displays and light sources.     

Plasma induced patterning of polydimethylsiloxane surfaces

We report on a plasma-based method to fabricate chemical and physical patterns on polydimethylsiloxane (PDMS) surfaces. A copper TEM grid was placed on cured, planar (2D) and periodic (3D) PDMS surfaces, and the samples exposed to a low-pressure “air” plasma. The pattern of the grid was precisely replicated, forming hydrophilic channels only where the grid wires contacted the PDMS surface. Exposed regions of the surface between the mesh wires were not chemically modified and retained their hydrophobic character. This plasma-based procedure provides a simple, fast, and inexpensive method for creating patterned chemical functionalities on 2D and 3D PDMS surfaces for directed assembly and for the development of micro-scale sensors and bio-chip devices.     

Six-Sigma project selection using national quality award criteria and Delphi fuzzy multiple criteria decision-making method

Six-Sigma is a tactical tool of significant value in achieving operational excellence. The project selection decision, under a resources constraint, is the early stage of implementation for a Six-Sigma intervention. The project selection decision is challenging due to its fuzzy group decision-making aspect inherent to the problem. The present study proposes to adopt national quality award criteria as the Six-Sigma project selection criteria, and proposes a hierarchical criteria evaluation process. The strategic criteria are evaluated by the management team using a Delphi fuzzy multiple criteria decision-making method. Then, the tactical sub-criteria which contain additional operational issues are evaluated by the Six-Sigma Champion. The proposed methodology is successfully applied in solving the project selection problem deriving from a component manufacturer. The empirical outcomes are promising. Moreover, the results show that the higher a project’s priority is, the greater the financial gains will be on completion of the project. Accordingly, the proposed methodology can prioritize the financial gain – which is the key performance indicator for a Six-Sigma project. Additionally, the quality status of the case company has been significantly improved through implementation of the Six-Sigma project. The systematic evaluation process also influences employees to adopt an analytical operations philosophy. Moreover, the commercial objectives of the company are brought into focus by the proposed methodology.     

Trend transformation of drain-current degradation under drain-avalanche hot-carrier stress for CLC n-TFTs

Continuous-wave green laser-crystallized (CLC) single-grain-like polycrystalline silicon n-channel thin-film transistors (poly-Si n-TFTs) demonstrate the higher electron mobility and turn-on current than excimer laser annealing (ELA) poly-Si n-TFTs. Furthermore, high drain voltage accelerates the flowing electrons in n-type channel, and hence the hot-carriers possibly cause a serious damage near the drain region and deteriorate the source/drain (S/D) current. In this study, at high drain stress voltage, it appears that CLC TFT was degraded in the initial stress time (before 50 s), but the drain current was enhanced after 50 s. After 50 s stress time, the amount of grain boundary trap states near the drain side was getting large and the reflowing holes damaged the source region or injected into gate oxide near source side as well.     

Structural Basis for the Improved Potency of Peroxisome Proliferator‐Activated Receptor (PPAR) Agonists

The need to develop safer and more effective antidiabetic drugs is essential owing to the growth worldwide of the diabetic population. Targeting the PPAR receptor is one strategy for the treatment of diabetes; the PPAR agonists rosiglitazone and pioglitazone are already on the market. Here we report the identification of a potent PPAR agonist, 15 , whose PPARγ activation was more than 20 times better than that of rosiglitazone. Compound 15 was designed to incorporate an indole head with a carboxylic acid group, and 4‐phenylbenzophenone tail to achieve a PPARγ EC₅₀ of 10 nM . Compound 15 showed the most potent PPARγ agonist activity among the compounds we investigated. To gain molecular insight into the improved potency of 15 , a structural biology study and binding energy calculations were carried out. Superimposition of the X‐ray structures of 15 and agonist 10 revealed that, even though they have the same indole head part, they adopt different conformations. The head part of 15 showed stronger interactions toward PPARγ; this could be due to the presence of the novel tail part 4‐phenylbenzophenone, which could enhance the binding efficiency of 15 to PPARγ.     

Modeling Harmonic Distortions Caused by Nonlinear Op-Amp DC Gain for Switched-Capacitor Sigma–Delta Modulators

Op-amps are crucial components in sigma-delta modulators (SDMs). As device dimensions and supply voltages continue to scale down, it is increasingly critical to determine a suitable op-amp dc gain. If the dc gain is set too high, then the op-amp consumes too much power; if the dc gain is too small, then nonlinear distortion becomes serious. However, there exists no efficient approach for selecting dc gains. In this brief, we propose to use a nonlinear function to model nonlinear op-amp dc gain curves. Then, this nonlinear function is employed to derive an SDM nonlinear distortion model as a function of SDM system parameters. The obtained SDM nonlinear distortion model can subsequently be used to compute the minimum required op-amp dc gain such that nonlinear distortions are kept under a tolerable value. The nonlinear dc gain curve model and the SDM nonlinear distortion model proposed in this brief are verified by behavior simulations and transistor-level simulations.     

Study of Al–Ti/Si bi-layer as the recording media for write-once HD-DVD optical disks

Optimum structure for HD-DVD optical disks containing Al–Ti/Si bi-layer recording system was identified by reflectivity simulation and dynamic test of disk samples. For the disk sample with optimized structure, the maximum partial response signal-to-noise ratio (PRSNR) of 19.1 dB, minimum simulated bit error rate (sbER) of 1.7 × 10^?7 and modulation >0.6 were achieved at the writing power (P_w) = 11.2 mW. Transmission electron microscopy (TEM) revealed that the polycrystalline granular clusters constitute the recording marks. Subsequent analyses evidenced that element mixing/alloy reactions occur in between Si and Al–Ti layers and the formation of Al_3.21Si_0.47 crystalline phase is responsible for the signal recording in the disk samples.