Effect of maleated EVA on compatibility and toughness of PETG/EVA blend

Maleic anhydride (MAH) grafted onto ethylene vinyl acetate copolymer (EVA), mEVA (modified EVA) was blended with poly(ethylene glycol‐co‐cyclohexane‐1,4‐dimethanol terephthalate) (PETG) with various mEVA and EVA (unmodified) content in the internal mixer. The effect of reactive compatibilizer to decrease the dispersed particle diameter was observed. The brittle–ductile transition was found at about d_n: 0.37 µm and d_v: 0.55 µm of particle diameter, a critical particle diameter, regardless of EVA content, and the blend was also toughened at above the critical particle diameter regardless of dispersed EVA content and compatibility. The toughening mechanism and the effect of the particle diameter on the impact strength of the blend were investigated by morphological observation, and it was found that the toughening of the PETG/EVA blend system resulted from the shear deformation, induced by cavitation of dispersed EVA particles. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

A study on the spray structure and evaporation characteristic of common rail type high pressure injector in homogeneous charge compression ignition engine

The purpose of this study was to investigate the spray structure and evaporation characteristics of common rail high pressure injector for use in a direct injection type HCCI (Homogeneous Charge Compression Ignition) engine. In this study, we measured the injection rate and visualized the spray structure of a HCCI injector according to injection conditions. The CFD simulation of the spray and the air fuel mixture formation in real engine conditions was also conducted using the VECTIS commercial code. In addition, we compared simulation results to experimental results.

From the spray experiment and simulation results, we found that the spray penetration was proportional to the back pressure by an exponent of 1/4. This is similar to Hiroyasu's experimental result. The fuel evaporation and air fuel mixture result indicate that the influence of the spray impingement with the ambient density was bigger than that of the intake pressure and temperature conditions in evaporation rate when the fuel was injected at the early stage of the compression stroke. The results also reveal that the fuel was uniformly distributed in the combustion chamber at this early injection time and the air fuel mixture was enhanced in this relatively rich region. However, when ambient density was kept constant, the fuel evaporation was sensitive to the influence of the intake temperature and pressure. As the fuel was injected at the later stage of the compression stroke, the fuel tended to concentrate in the bowl zone and to generate the lean air fuel mixture. From these results, it was confirmed that the air fuel mixture characteristics are sensitive to the impingement position of the injected fuel.     

Sound transducer calibration of ambulatory audiometric system utilizing delta learning rule

An efficient calibration algorithm for an ambulatory audiometric test system is proposed. This system utilizes a personal digital assistant (PDA) device to generate the correct sound pressure level (SPL) from an audiometric transducer such as an earphone. The calibrated sound intensities for an audio-logical examination can be obtained in terms of the sound pressure levels of pure-tonal sinusoidal signals in eight-banded frequency ranges (250, 500, 1 000, 2 000, 3 000, 4 000, 6 000 and 8 000 Hz), and with mapping of the input sound pressure levels by the weight coefficients that are tuned by the delta learning rule. With this scheme, the sound intensities, which evoke eight-banded sound pressure levels by 5 dB steps from a minimum of 25 dB to a maximum of 80 dB, can be generated without volume displacement. Consequently, these sound intensities can be utilized to accurately determine the hearing threshold of a subject in the ambulatory audiometric testing environment.     

Decomposition of NH3 over Zn–Ti-based desulfurization sorbent promoted with cobalt and nickel

Zn–Ti-based sorbents promoted with cobalt and nickel additive were prepared by simple physical mixing of single oxides. Their capacities for removing H₂S and NH₃ simultaneously, emitted from coal gasifiers, were investigated in a micro-reactor at 1 atm and 650 °C. NH₃ within the fuel gases did not affect the sulfur removing capacity of the Zn–Ti-based sorbent. The additives, cobalt and nickel, were found to be active components in NH₃ decomposition as well as H₂S absorption, while major components such as ZnO and TiO₂ did not show any activity in the NH₃ decomposition reaction. NH₃ was decomposed over both oxide and sulfide forms of the additives, even though the NH₃ decomposition ability of their sulfides dramatically decreased in the presence of H₂ gas owing to the equilibrium limitation of NH₃ decomposition. In the case of oxide forms, cobalt oxide showed excellent NH₃ decomposition capacity regardless of H₂ concentrations, while the capacity of nickel oxide depended on the H₂ concentrations.     

Improved photostability of a CuO photoelectrode with Ni-doped seed layer

In this study, we examined the growth of copper oxide (CuO) photoelectrodes using nickel-doped copper oxide seed layers with various doping concentrations. We investigated the effects of the seed layer doped with various amounts of nickel on the morphological, structural, optical and photoelectrochemical properties of the CuO photoelectrode by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and potentiostat/galvanostat measurements, respectively. We found that doping the seed layer with nickel affects properties such as the surface roughness, surface area, crystallinity and photostability. As a result, we obtained a maximum photostability of 46.2% using a 10 at% nickel-doped seed layer.     

Conductive and transparent submicron polymer lens array fabrication for electrowetting applications

In this study, we have demonstrated a simple and inexpensive process to fabricate electrowetting lens arrays with various curvatures (micron to submicron) on conductive and transparent polydimethylsiloxane (PDMS) molds without additional metal layers. The microlens arrays were fabricated using one-step dual diffuser lithography process, which utilizes a pair of diffusers to diffract the incident rays of UV light at wide angles before approaching the photoresist. Dimensional control and high fill factor was achieved by just varying the exposure energy and gap between the patterns in the photomask, respectively. The patterns were replicated in conductive and transparent Ag(n)-PDMS (5–20% Ag) with 15 μm thickness. High conductivity of 4.6 × 10^?1 S/m and high transmission efficiency of 90% was demonstrated by Ag(n)-PDMS molds. Micro-nanolens arrays fabricated by the optimized corelation were utilized to demonstrate switchable wettability behavior of water droplet at different applied voltages. The electrowetting microlens array fabrication method introduced in this work has high potential to be incorporated in optoelectronics and biomedical devices.     

Inducible <Emphasis Type="Italic">De Novo</Emphasis> Biosynthesis of Isoflavonoids in Soybean Leaves by <Emphasis Type="Italic">Spodoptera litura</Emphasis> Derived Elicitors: Tracer Techniques Aided by High Resolution LCMS

Isoflavonoids are a characteristic family of natural products in legumes known to mediate a range of plant-biotic interactions. For example, in soybean (Glycine max: Fabaceae) multiple isoflavones are induced and accumulate in leaves following attack by Spodoptera litura (Lepidoptera: Noctuidae) larvae. To quantitatively examine patterns of activated de novo biosynthesis, soybean (Var. Enrei) leaves were treated with a combination of plant defense elicitors present in S. litura gut content extracts and L-α-[¹³C₉, ¹⁵N]phenylalanine as a traceable isoflavonoid precursor. Combined treatments promoted significant increases in ¹³C-labeled isoflavone aglycones (daidzein, formononetin, and genistein), ¹³C-labeled isoflavone 7-O-glucosides (daidzin, ononin, and genistin), and ¹³C-labeled isoflavone 7-O-(6″-O-malonyl-β-glucosides) (malonyldaidzin, malonylononin, and malonylgenistin). In contrast levels of ¹³C-labeled flavones and flavonol (4′,7-dihydroxyflavone, kaempferol, and apigenin) were not significantly altered. Curiously, application of fatty acid-amino acid conjugate (FAC) elicitors present in S. litura gut contents, namely N-linolenoyl-L-glutamine and N-linoleoyl-L-glutamine, both promoted the induced accumulation of isoflavone 7-O-glucosides and isoflavone 7-O-(6″-O-malonyl-β-glucosides), but not isoflavone aglycones in the leaves. These results demonstrate that at least two separate reactions are involved in elicitor-induced soybean leaf responses to the S. litura gut contents: one is the de novo biosynthesis of isoflavone conjugates induced by FACs, and the other is the hydrolysis of the isoflavone conjugates to yield isoflavone aglycones. Gut content extracts alone displayed no hydrolytic activity. The quantitative analysis of isoflavone de novo biosynthesis, with respect to both aglycones and conjugates, affords a useful bioassay system for the discovery of additional plant defense elicitor(s) in S. litura gut contents that specifically promote hydrolysis of isoflavone conjugates.     

Photo-Cross-Linking between BrU and Pyrene Residues in an RNA/DNA Hybrid

In this study, we investigated the photoreaction of ^BrU in a pyrene-labeled DNA duplex, RNA duplex, and DNA/RNA hybrids. We found that the photoreactivity of ^BrU changed dramatically from hydrogen abstraction to cross-linking by changing the conformation of the duplex from the B-form to the A-form. Among three A-form structures, the largest amount of cross-linked products was observed when ^BrU was incorporated into the RNA strand and the pyrene was conjugated to the 5′ end of the DNA. These results indicate that the contact manner of pyrene was different between A- and B-form duplexes. This is a rare example of the use of the reactivity of bromouracil to analyze the contact between a small molecule with a weak binding affinity and a nucleic acid.     

Effect of interface affinity on the performance of a composite of microcrystalline cellulose and polypropylene/polylactide blends

The effects of compatibilizer and fillers on the mechanical properties and dispersion state of droplets of polypropylene (PP)/polylactide (PLA) blends were investigated. Two blended composite systems, i.e. PP‐rich (80/20) containing microcrystalline cellulose (MCC) modified with silane (m‐MCC) and PLA‐rich (20/80) containing MCC were prepared by melt compounding using a twin‐screw extruder. The structural differences between MCC and m‐MCC were confirmed using Fourier transform infrared spectra. Universal testing machine results revealed that the tensile strength and Young's modulus increased with the addition of compatibilizer and filler, respectively. These results were supported by the reduction of domain size observed by scanning electron microscopy. Differential scanning calorimetric analysis showed a change of the melting and crystallization behavior of blends according to the presence of compatibilizer or filler. An increase of the dynamic storage modulus and a decrease in tan δ with addition of compatibilizer indicated that the interfacial adhesion between PP and PLA improved. © 2019 Society of Chemical Industry     

Large enhancement of light extraction efficiency in AlGaN-based nanorod ultraviolet light-emitting diode structures

Light extraction efficiency (LEE) of AlGaN-based nanorod deep ultraviolet (UV) light-emitting diodes (LEDs) is numerically investigated using three-dimensional finite-difference time-domain simulations. LEE of deep UV LEDs is limited by strong light absorption in the p-GaN contact layer and total internal reflection. The nanorod structure is found to be quite effective in increasing LEE of deep UV LEDs especially for the transverse magnetic (TM) mode. In the nanorod LED, strong dependence of LEE on structural parameters such as the diameter of a nanorod and the p-GaN thickness is observed, which can be attributed to the formation of resonant modes inside the nanorod structure. Simulation results show that, when the structural parameters of the nanorod LED are optimized, LEE can be higher than 50% and 60% for the transverse electric (TE) and TM modes, respectively. The nanorod structure is expected to be a good candidate for the application to future high-efficiency deep UV LEDs.

PACS

41.20.Jb; 42.72.Bj; 85.60.Jb