Effects of Interfacial Dielectric Layers on the Electrical Performance of Top‐Gate In‐Ga‐Zn‐Oxide Thin‐Film Transistors

We investigate the effects of interfacial dielectric layers (IDLs) on the electrical properties of top‐gate In‐Ga‐Zn‐oxide (IGZO) thin film transistors (TFTs) fabricated at low temperatures below 200°C, using a target composition of In:Ga:Zn = 2:1:2 (atomic ratio). Using four types of TFT structures combined with such dielectric materials as Si₃N₄ and Al₂O₃, the electrical properties are analyzed. After post‐annealing at 200°C for 1 hour in an O₂ ambient, the sub‐threshold swing is improved in all TFT types, which indicates a reduction of the interfacial trap sites. During negative‐bias stress tests on TFTs with a Si3N4 IDL, the degradation sources are closely related to unstable bond states, such as Si‐based broken bonds and hydrogen‐based bonds. From constant‐current stress tests of Id = 3 µA, an IGZO‐TFT with heat‐treated Si₃N₄ IDL shows a good stability performance, which is attributed to the compensation effect of the original charge‐injection and electron‐trapping behavior.     

Trilayer Nanomesh Films with Tunable Wettability as Highly Transparent,Flexible, and Recyclable Electrodes

Metallic mesh materials are promising candidates to replace traditional transparent conductive oxides such as indium tin oxide (ITO) that is restricted by the limited indium resource and its brittle nature. The challenge of metal based transparent conductive networks is to achieve high transmittance, low sheet resistance, and small perforation size simultaneously, all of which significantly relate to device performances in optoelectronics. In this work, trilayer dielectric/metal/dielectric (D/M/D) nanomesh electrodes are reported with precisely controlled perforation size, wire width, and uniform hole distribution employing the nanosphere lithography technique. TiO₂/Au/TiO₂ nanomesh films with small hole diameter (≤700 nm) and low thickness (≤50 nm) are shown to yield high transmittance (>90%), low sheet resistance (≤70 Ω sq^?1), as well as outstanding flexural endurance and feasibility for large area patterning. Further, by tuning the surface wettability, these films are applied as easily recyclable flexible electrodes for electrochromic devices. The simple and cost‐effective fabrication of diverse D/M/D nanomesh transparent conductive films with tunable optoelectronic properties paves a way for the design and realization of specialized transparent electrodes in optoelectronics.     

Solution‐Processible Multi‐component Cyclometalated Iridium Phosphors for High‐Efficiency Orange‐Emitting OLEDs and Their Potential Use as White Light Sources

The synthesis and photophysical studies of several multifunctional phosphorescent iridium(III) cyclometalated complexes consisting of the hole‐transporting carbazole and fluorene‐based 2‐phenylpyridine moieties are reported. All of them are isolated as thermally and morphological stable amorphous solids. Extension of the π‐conjugation through incorporation of electron‐pushing carbazole units to the fluorene fragment leads to bathochromic shifts in the emission profile, increases the highest occupied molecular orbital levels and improves the charge balance in the resulting complexes because of the propensity of the carbazole unit to facilitate hole transport. These iridium‐based triplet emitters give a strong orange phosphorescence light at room temperature with relatively short lifetimes in the solution phase. The photo‐ and electroluminescence properties of these phosphorescent carbazolylfluorene‐functionalized metalated complexes have been studied in terms of the coordinating position of carbazole to the fluorene unit. Organic light‐emitting diodes (OLEDs) using these complexes as the solution‐processed emissive layers have been fabricated which show very high efficiencies even without the need for the typical hole‐transporting layer. These orange‐emitting devices can produce a maximum current efficiency of ～ 30 cd A^–1 corresponding to an external quantum efficiency of ～ 10 % ph/el (photons per electron) and a power efficiency of ～ 14 lm W^–1. The homoleptic iridium phosphors generally outperform the heteroleptic counterparts in device performance. The potential of exploiting these orange phosphor dyes in the realization of white OLEDs is also discussed.     

Wavelet transform coding for MCP error images using quadtree decomposition and ECVQ

This paper proposes a new wavelet transform video coder which employs motion compensation, wavelet decomposition, and entropy-constrained vector quantization (ECVQ), in sequence. Each of layered subimages obtained from wavelet decomposition is segmented into basic blocks, and then the blocks are selectively encoded by ECVQ according to the energy of the samples. We introduce an efficient method to encode the map representing which blocks are encoded, based on inter-band prediction followed by a quadtree encoding. The proposed coder uses a simple forward analyzer in order to optimize the encoding parameters and introduces a preprocessing of signals which normalizes the input vectors of ECVQ in order to reduce the image-dependency of ECVQ codebooks. Simulation results show that our video coder provides good PSNR (peak-to-peak signal-to-noise ratio) performance and efficient rate control.     

Explicit rate allocation algorithm of generalised max-min fairnessfor ATM ABR services

A distributed explicit rate allocation algorithm based on the generalised max-min (GMM) fairness principle is proposed for the available bit rate (ABR) ATM services. Compared with a similar algorithm for GMM, it employs fewer fields in an RM cell and imposes lower requirements on the computational capability of the switches     

Recycling wasted scallop shell as an adsorbent for the removal of phosphate

Lots of scallop shells were discharged from local restaurants and marine product manufacturers around the city of Gangneung and most of them are dumped into landfill. The scallop shell was recycled as an adsorbent for the removal of phosphate. The shell size greatly affected phosphate removal. One gram of shell having diameter of around 45 μm removed 100 mg/L of phosphate in 3 h while that of 3 mm hardly removed in 80 h. Phosphate removal was not much affected by the pH in the range of 2.0–7.5 but it was scarcely removed beyond pH 8.0. Higher temperature was preferred for phosphate removal but the removal efficiency was almost constant over 35 °C. The maximum phosphate removal capacity was obtained through Langmuir isotherm plotting and it was as high as 23.0 mg-phosphate/g-shell. On the purpose of enhancing the adsorption capacity of scallop shell, it was treated with chemical reagents such as HCl, NaOH, NH₄HCO₃ and EDTA. HCl-treatment increased the adsorption capacity of the shell having diameter of 45 μm by 39.8% than raw scallop shell, but the treatment showed negligible effect on the shell of 1000 μm in diameter. Packed-bed containing HCl-treated scallop shell with 500 μm in diameter removed 20 mg/L of phosphate stably for 15 days and the removal efficiency was over 85% throughout operation.     

Extrusion coating performances of iPP/LDPE blends

The performance of iPP/LDPE blends in an extrusion coating process was investigated in the terms of coating width and draw‐down ability. It is well known that iPP alone is not proper because of lower draw‐down ability with severe draw resonance in elongational flow. To obtain higher draw‐down ability, iPP was blended with LDPE. Additionally, iPPs having different molecular weight distribution (MWD) were used in this study to find out the effect of MWD of iPP on neck‐in and draw‐down ability. It was observed that iPP/LDPE blend with narrower MWD exhibits narrower coating width and higher draw‐down ability. Neck‐in and draw‐down ability were correlated with shear and elongational properties obtained by several rheological measurements. From this study, the major rheological parameters affecting extrusion performance in iPP/LDPE blends could be assessed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Rubral tremor associated with cavernous angioma of the midbrain

The insecticidal activity of five alkylfurans against the generalist insect herbivore beet armyworm, Spodoptera exigua, was examined. Two naturally occurring compounds, the avocadofurans 2-(pentadecyl)furan (1) and 2-(heptadecyl)furan (2), previously isolated from specialized avocado idioblast oil cells, and three homologues, 2-(tetradecyl)furan (3), 2-(hexadecyl)furan (4), and 2-(octadecyl)furan (5), were synthesized. Bioassays of alkylfurans 1-5 using a 9-day diet-incorporation initiated with neonates showed that all alkylfurans tested significantly increased S. exigua larval mortality and reduced larval weights, with maximal biological activity detected among the naturally occurring alkylfurans 1 and 2.     

Cross sectional echocardiographic assessment of the extent of the atrial septum relative to the atrioventricular junction in atrioventricular septal defect

A study of brain lipids in patients with the sphingomyelinase-deficient types of Niemann-Pick disease demonstrated that abnormal accumulation of sphingomyelin occurs only in the brain of neuronopathic type A patients but not in the non-neuronopathic type B. Additional lipid abnormalities were present in the type A brain. In contrast, the brain lipid profile was normal in type B patients. Since lysosphingolipids have been implicated in the biochemical pathogenesis of other genetic lysosomal sphingolipidoses, the occurrence of sphingosylphosphorylcholine (lysosphingomyelin) was specifically investigated in brain and extraneural tissues, using an HPLC method with fluorescent detection of orthophtalaldehyde derivatives. Levels close to or below the limit of detection (10 pmol/mg tissue protein) were observed in normal and pathological controls. A striking accumulation was observed in brain of two Niemann-Pick type A patients (830 and 430 pmol/mg protein in 27-and 16-month-old children with severe and milder neurological course, respectively), which was not present at the fetal stage of the disease. No significant increase was found in brain tissue from a 3.5 year-old type B patient. In liver and spleen, abnormally high sphingosylphosphorylcholine levels were observed in both types of the disease, with indication of a progressive increase during development. This study establishes the integrity of brain tissue in Niemann-Pick disease type B and suggests that the lysocompound sphingosylphosphorylcholine could play a role in the pathophysiology of brain dysfunction in the neuronopathic type A.