A new threshold‐voltage compensation technique of poly‐Si TFTs for AMOLED display pixel circuits

Abstract— A new threshold‐voltage compensation technique for polycrystal line‐silicon thin‐film transistors (poly‐Si TFTs) used in active‐matrix organic light‐emitting‐diode (AMOLED) display pixel circuits is presented. The new technique was applied to a conventional 2‐transistor—1‐capacitor (2T1C) pixel circuit, and a new voltage‐programmed pixel circuit (VPPC) is proposed. Theoretically, the proposed pixel is the fastest pixel with threshold‐voltage compensation reported in the literature because of the new compression technique implemented with a static circuit block, which does not affect the response time of the conventional 2T1C pixel circuit. Furthermore, the new pixel exhibits all the other advantages of the 2T1C pixel, such as the simplicity of the peripheral drivers and improves other characteristics, such as its behavior in the temperature variations. The verification of the proposed pixel is made through simulations with HSpice. In order to obtain realistic simulations, device parameters were extracted from fabricated low‐temperature poly‐Si (LTPS) TFTs.     

Silver-doped biphasic calcium phosphate/alginate microclusters with antibacterial property and controlled doxorubicin delivery

Biphasic calcium phosphate (BCP) based materials possessed with both excellent biocompatibility and antibacterial activity show potential advantages for biomedical applications. Here, the silver-doped BCP/Alginate (_AgBA) microclusters were first fabricated using the double-emulsions method. First, BCP nanoparticles were incorporated into the alginate network to form BCP/Alginate microclusters via the emulsion process. Then, silver nanoparticles (AgNPs) were in situ involved in BCP/Alginate networks to obtain the final _AgBA microclusters. Transmission electron microscopy and scanning electron microscopy confirmed that BCP nanoparticles and AgNPs were uniformly distributed in _AgBA microclusters. The morphology of _AgBA microclusters could be regulated by adjusting emulsion power, and microclusters using the medium powder (500 W) showed a regular spherical shape. Furthermore, CCK-8 analysis identified that _AgBA microclusters were cytocompatible culturing with human bone marrow-derived mesenchymal stem cells. Qualitative antibacterial tests exhibited the excellent inhibition effects of _AgBA microclusters against Staphylococcus aureus (Gram-positive) and Escherichia coli. (Gram-negative). Lastly, the doxorubicin (DOX)-loaded _AgBA microclusters presented adjustable loading efficiency of DOX and controllable release profiles. The cumulative release could reach 73.3% after 72 h in PBS. The above results raised a new route for antibacterial microclusters development for biomedical applications.     

A New Analog Buffer Using Low-Temperature Polysilicon Thin-Film Transistors for Active-Matrix Displays

In this paper, a new source-follower-type analog buffer for active-matrix displays, designed by using low-temperature polysilicon thin-film transistors (TFTs), is proposed. The buffer, consisting of five n-type polysilicon TFTs, one bias voltage, and an additional control signal, exhibits high immunity to threshold voltage and mobility variations. The functionality of the proposed buffer was verified by HSPICE simulations. In order to obtain realistic simulations, the TFT model parameters used for the simulations were extracted from fabricated TFTs using the Silvaco tools (ATLAS). The proposed buffer has 7-bit output voltage with the dynamic output voltage range of 7.5 V ranging from 2.5 to 10 V and with resolution up to 0.03 V     

Model catalyst studies with single crystals and epitaxial thin oxide films

The paper describes recent results from our relatively new program to perform detailed studies of the catalytic properties of metal-oxide materials; in particular, to effect a determination of the active catalytic site(s) and the mechanism for reactions over this especially important class of heterogeneous catalysts. Issues of structure-sensitivity, poisoning and promotion, and competing reaction mechanisms are critical questions that need to be addressed in a detailed manner for catalysis by oxides. As just one important example, both surface (Langmui–Hinshelwood) and direct (Eley–Rideal) reaction mechanisms have been proposed for the selective catalytic reduction (SCR) reaction of nitrogen oxides (NO_x) over vanadia/titania catalysts. For this program, we are using a number of unique, state-of-the-art capabilities available in the Environmental Molecular Sciences Laboratory (EMSL) at Pacific Northwest National Laboratory; for example, the first molecular beam epitaxy (MBE) system dedicated to the growth of model metal-oxide films, and a unique moderate-pressure catalytic reactor/surface science apparatus. We describe the growth, characterization, and water adsorption properties of a thin Fe₃O₄(0 0 1) film grown on a lattice-matched MgO(0 0 1) substrate. Because our moderate pressure catalysis studies are preliminary at this point, we instead describe our previous results on the CO oxidation reaction over a Ru(0 0 0 1) model catalyst to demonstrate the utility of the experimental approach. We specifically discuss the possibility that this reaction occurs by an Eley–Rideal mechanism.     

Dispersive liquid–liquid microextraction for the determination of organochlorine pesticides residues in honey by gas chromatography-electron capture and ion trap mass spectrometric detection

A simple dispersive liquid–liquid microextraction (DLLME) protocol for the determination of 15 organochlorine pesticides residues in honey is proposed. The selected pesticides were separated using gas chromatography and detected by electron capture (ECD) or ion trap mass spectrometry (GC-IT/MS). Several parameters affecting the extraction efficiency namely type and volume of organic extraction solvent, type and volume of disperser solvent, sample pH, ionic strength, extraction time and centrifugation speed were systematically investigated. The final DLLME protocol involved the addition of 750 μL acetonitrile (disperser) and 50 μL chloroform (extraction solvent) into a 5 mL aqueous honey solution followed by centrifugation. The sedimented organic phase (chloroform) were analysed directly by GC-IT/MS or evaporated and reconstituted in acetonitrile prior to the GC-ECD analysis. The analytical performance of the GC-ECD and GC-IT/MS methods was compared and discussed. Under the selected experimental conditions, the enrichment factors varied between of 36 and 114. The limits of detection (LOD) were in the range of 0.02–0.15 μg L⁻¹ (0.4–3 ng g⁻¹) for GC-ECD and 0.01–0.2 μg L⁻¹ (0.2–4 ng g⁻¹) for GC-IT/MS which is adequate to verify compliance of products to legal tolerances. The proposed method was applied to the analysis of the selected organochlorine pesticides residues in various honey samples obtained from Greek region. Mean recoveries were ranged from 75% to 119% while the precision was better than 20% in both methodologies.     

BIAS-CORRECTED NONPARAMETRIC SPECTRAL ESTIMATION

Abstract. The theory of nonparametric spectral density estimation based on an observed stretch X₁,…, X_N from a stationary time series has been studied extensively in recent years. However, the most popular spectral estimators, such as the ones proposed by Bartlett, Daniell, Parzen, Priestley and Tukey, are plagued by the problem of bias, which effectively prohibits ?N-convergence of the estimator. This is true even in the case where the data are known to be m-dependent, in which case ?N-consistent estimation is possible by a simple plug-in method. In this report, an intuitive method for the reduction in the bias of a nonparametric spectral estimator is presented. In fact, applying the proposed methodology to Bartlett's estimator results in bias-corrected estimators that are related to kernel estimators with lag-windows of trapezoidal shape. The asymptotic performance (bias, variance, rate of convergence) of the proposed estimators is investigated; in particular, it is found that the trapezoidal lag-window spectral estimator is ?N-consistent in the case of moving-average processes, and ?(N/log/N)-consistent in the case of autoregressive moving-average processes. The finite-sample performance of the trapezoidal lag-window estimator is also assessed by means of a numerical simulation.     

Transforming communicating X-machines into P systems

Tissue P systems (tPS) represent a class of P systems in which cells are arranged in a graph rather than a hierarchical structure. On the other hand, communicating X-machines (XMs) are state-based machines, extended with a memory structure and transition functions instead of simple inputs, which communicate via message passing. One could use communicating XMs to create models built out of components in a rather intuitive way. There are investigations showing how various classes of P systems can be modelled as communicating XMs. In this paper, we define a set of principles to transform communicating XMs into tPS. We describe the rules that govern such transformations, present an example to demonstrate the feasibility of this approach and discuss ways to extend it to more general models, such as population P systems, which involve dynamic structures.