Simultaneous Optimization of Luminance and Color Chromaticity of Phosphors Using a Nondominated Sorting Genetic Algorithm

Acquiring materials that simultaneously meet two or more conflicting requirements is very difficult. For instance, a situation wherein the color chromaticity and photoluminescence (PL) intensity of phosphors conflict with one another is a frequent problem. Therefore, identification of a good phosphor that simultaneously exhibits both desirable PL intensity and color chromaticity is a challenge. A high‐throughput synthesis and characterization strategy that was reinforced by a nondominated sorting genetic algorithm (NSGA)‐based optimization process was employed to simultaneously optimize both the PL intensity and color chromaticity of a MgO–ZnO–SrO–CaO–BaO–Al₂O₃–Ga₂O₃–MnO system. NSGA operations, such as Pareto sorting and niche sharing, and the ensuing high‐throughput synthesis and characterization resulted in identification of promising green phosphors, i.e., Mn²⁺‐doped AB₂O₄ (A = alkali earth, B = Al and Ga) spinel solid solutions, for use in either plasma display panels or cold cathode fluorescent lamps.     

Investigation of the Device Degradation Mechanism in Pentacene-Based Thin-Film Transistors Using Low-Frequency-Noise Spectroscopy

The degradation process in pentacene-based organic thin-film transistors (OTFTs) is investigated. Pentacene-based OTFTs were fabricated with and without octadecyl trichlorosilane (OTS) treatment, and their device characteristics during lifetime test are evaluated using low-frequency-noise (LFN) spectroscopy. It is found that the devices exhibited the $hbox{1}/f$ type of noise behavior with generation and recombination noise superimposed. The drain-current noise was found to vary proportionally with drain current according to Hooge's empirical relation of flicker noise. Devices without any treatment show obvious interface traps and deep-level traps, while devices with OTS treatment show nonexistence of interface traps and suppression of deep-level traps. The LFN intensity is found to decrease during the device lifetime test initially, while upon the device failure, the noise level is observed to increase again. The viability of using LFN as a diagnostic tool in the organic transistor is demonstrated.      

Development of Vancomycin-Capped β-CD-Bonded Silica Particles as Chiral Stationary Phase for LC

Vancomycin-capped (3-(2-O-β-cyclodextrin)-2-hydroxypropoxy)-propylsilyl-appended silica particles (VCD-HPS), a new type of substituted β-cyclodextrin-bonded chiral stationary phase (CSP) for liquid chromatography (LC), have been synthesized by treatment of bromoacetate-substituted-(3-(2-O-β-cyclodextrin)-2-hydroxypropoxy)-propylsilyl-appended silica particles (BACD-HPS) with vancomycin in anhydrous methanol. The stationary phase is characterized by elemental analysis. This new CSP has a chiral selector with two recognition sites: vancomycin and β-cyclodextrin (β-CD), which can provide multiple interactions with the solutes. The chromatographic performance of VCD-HPS was studied with several disubstituted benzenes and some chiral drug compounds as solutes in reversed-phase LC. The results show that VCD-HPS has excellent selectivity for the separation of aromatic positional isomers and enantiomers of chiral compounds.     

Synthesis and optical properties of 10 mol% Ce, 5 mol% Tb co-doped KGdF4 and GdF3 submicro/nanocrystals

By controlling the pH values of prepared solutions, the 10 mol% Ce³⁺, 5 mol% Tb³⁺ co-doped KGdF₄ (synthesized with pH = 3) and the 10 mol% Ce³⁺, 5 mol% Tb³⁺ co-doped GdF₃ (synthesized with pH = 1) submicro/nanocrystals have been synthesized based on a citric acid assisted hydrothermal method. For comparison, the samples synthesized by co-precipitation method (without hydrothermal treatment) with pH = 3 and 1 were also collected. The X-ray diffraction data illustrate that the hydrothermal treated KGdF₄ sample crystallizes in the cubic phase and the GdF₃ sample crystallizes in the orthorhombic phase. However, the samples synthesized by co-precipitation method with pH = 3 and 1 are both cubic phase KGdF₄. The field emission scanning electron microscopy images suggest that the hydrothermal treated KGdF₄ submicro/nanocrystals present spherical morphology and the GdF₃ submicrocrystals are rhombic-shaped. And the photoluminescence excitation and emission spectra as well as the luminescent dynamic curves demonstrate the difference in optical properties of the two hydrothermal treated samples.     

Low emissivity Ag/Si/glass thin films deposited by sputtering

Si was deposited on the glass substrate as an interlayer for the 2-D growth of Ag thin films because Si has a strong binding energy against Ag and can lead to a negative surface energy change in Ag/glass. The Si interlayer induced an extremely smooth and flat Ag surface, which effectively reduced the resistance and enhanced the reflectance in the IR region. In particular, Ag (9 nm)/Si (3 nm)/glass showed 0.074 emissivity and ∼91% reflectance in the IR region with 67% transmittance in the visible region.     

Theoretical and experimental study of 10 Gb/s transmissionperformance using 1.55 μm LiNbO3-based transmitters withadjustable extinction ratio and chirp

This paper has experimentally and theoretically investigated transmission performance depending on chirping and extinction ratio for a 10 Gb/s transmission system with the standard single-mode fiber. The transmission performance can be dramatically degraded or improved by adjusting chirp and extinction ratio in a 1.55 μm LiNbO₃ modulator-based transmitter and erbium-doped fiber amplifier (EDFA)-pin diode receiver configuration. To estimate the transmission performance, bit error rate (BER) characteristics rather than eye-opening penalty (EOP) have been calculated by solving the nonlinear Schrodinger equation with including the model of chirping and extinction ratio for the transmitter, and noise and intersymbol interference for the receiver. This simulation can predict the measured BER characteristics well enough to see interplaying between chirping and extinction ratio     

Determination of Allosteric Effects and Interstrand Bidentate Interactions in DNA‐Peptide Molecular Recognition

To study DNA allostery, quantitative DNase I footprinting studies were carried out on a newly designed peptide His‐Hyp‐Lys‐Lys‐(Py)₄‐Lys‐Lys‐NH₂ (HypKK‐10) containing the XHypKK (Hyp = hydroxyproline) and polyamide motifs. The interconnection of DNA footprints of peptides HypKK‐10 and the parent peptide PyPro‐12 supports the proposal that interaction network cooperativity is preferred in DNA‐peptide interactions between multiple recognition sites. A simple method of determining interstrand bidentate interactions between the peptide moieties and DNA bases is introduced. It is envisaged that interstrand bidentate interactions also participate in the relay of conformational changes to recognition sites on the complementary strands. Circular dichroism studies of the titration of peptide HypKK‐10 with an oligonucleotide duplex indicate that this peptide binds in a dimeric fashion to DNA in the minor groove. This work may prompt the design of new DNA binding ligands for the study of DNA‐peptide allosteric interactions and DNA interaction network.     

Risk in Inventory Models: The Case of the Newsboy Problem — Optimality Conditions

A recent article in this journal employs the capital-asset pricing model for the analysis of the newsboy problem and shows how the covariance risk affects the optimal inventory policy. The purpose of this paper is to sharpen the optimality conditions given by the article and hence to provide a simple method for finding the solution. Under reasonable assumptions, this paper shows that the optimal ordering policy can be described by a single equation, regardless of the sign of the covariance term.     

Multi-domain architecture for policy management inumts ip multimedia subsystem

The Universal Mobile Telecommunications System (UMTS) offers IP-based multimedia applications and services with end-to-end Quality of Service (QoS) guarantee. The key component providing these services is the IP Multimedia Subsystem (IMS) that uses Service-Based Local Policy (SBLP) management for QoS control. To support end-to-end QoS, the UMTS IMS network should be scalable, reliable and flexible in policy deployment and enforcement, characteristics that are not found in single-domain policy architecture. A hybrid policy architecture is proposed, in which a hierarchical architecture is applied to the multi-domain environment in a single operator UMTS IMS network, while a peering architecture is employed in a multi-operator UMTS IMS network. The proposed multi-domain policy architecture potentially minimizes the session setup delay and policy exchange traffic while maximizing network scalability.     

Packet Delay Analysis of Symmetric Gated Polling System for DBA Scheme in an EPON

In this paper, we analyze the mean packet delay of a dynamic bandwidth allocation (DBA) scheme in an Ethernet passive optical network (EPON). We propose the interleaved polling system with a gated service discipline and a two-stage queue in order to investigate the delay performance of DBA scheme in an EPON. We assume that input packets arrive at an optical network unit (ONU) according to a Poisson process from several types of users. We use a continuous time queueing model in order to find the mean packet delay and the mean cycle time of an arbitrary packet. We obtain the closed form solution for the mean packet delay of the proposed gated polling system with a two-stage queue. We obtain another result on the mean packet delay by solving a system of linear equations derived from the moments of the queue length distribution. We give some numerical results to investigate the delay performances for the symmetric polling system with statistically identical stations. In addition, we compare numerical results on the closed form solution with numerical results on a system of linear equations.