Association of manganese effluent with the application of fertilizer and manure on tea field

Manganese (Mn) concentrations in the tea field effluent were 1.1-3.5 mg/l over a 2 year period from June 1997 to May 1998 (first water year) and June 1998 to May 1999 (second water year). The annual Mn loads were 38,000 g/ha in the first water year and 19,000 g/ha in the second. The highest Mn loads were observed, respectively, in July 1997 (10,000 g/ha) in the first water year and in June 1998 (4100 g/ha) in the second. The water-soluble Mn content of soil of the tea field increased abruptly with decreasing soil pH in the pH region below 4.5. The large Mn load from the tea field during the rainy season is likely due to application of excess fertilizer and manure before the rainy season, which may lead to acidification of the soil.     

High‐performance white OLEDs with high color‐rendering index for next‐generation solid‐state lighting

Abstract— Several white‐OLED structures with a high color‐rendering index (CRI) were investigated for lighting applications. A two‐unit fluorescent/phosphorescent hybrid white OLED achieved an excellent CRI of 95, high luminous efficacy of 37 lm/W, and long lifetime of over 40,000 hours at 1000 cd/m². White‐OLED lighting panels of 8 × 8 cm for high‐luminance operation were fabricated, and a stable emission at 3000 cd/m² was confirmed. Quite a small variation in chromaticity in a different directions was achieved by using an optimized optical device structure. With a light‐outcoupling substrate, a higher efficacy of 56 lm/W, high CRI of 91, and longer half‐decay lifetime of over 150,000 hours at 1000 cd/m² was achieved. All‐phosphorescent white OLEDs placed on the light‐outcoupling substrate show a high CRI of 85 and higher efficacy of 65 lm/W with a fairly good half‐decay lifetime of over 30,000 hours. With a further voltage reduction and a high‐index spherical extractor, 128 lm/W at 1000 cd/m² has been achieved.     

Wave-front design algorithm for shaping a quasi-far-field pattern

To design a fully continuous wave-front distribution suitable for focused beam shaping by a deformable mirror, we modify the phase-retrieval algorithm by employing a uniformly distributed phase as a starting phase screen and spatial filtering for the near-field phase retrieved during the iteration process. A special phase unwrapping algorithm is not required to obtain a continuous phase distribution from the retrieved phase since the boundary of the 2pi-phase-jumped region in the designed phase distribution is perfectly closed. From the computational result producing a uniform square beam transformation from a circular defocused beam, this algorithm has provided a fully continuous wave-front distribution with a lower spatial frequency for a deformable mirror. The transformed square beam has a normalized intensity nonuniformity of varsigma(rms) = 0.14 with respect to a desired flat-topped square beam pattern. This beam-shaping method also provides a high energy-concentration rate of more than 98%.     

High-aspect-ratio line focus for an x-ray laser by a deformable mirror

A high-aspect-ratio line focus is required on a plane target in x-ray laser experiments for obtaining a high gain-length product. Inherent wave-front aberrations in line-focusing optics, which consist of a cylindrical lens and a spherical lens, are discussed with respect to beam diameter. The nonuniformity of the linewidth that is due to the aberrations is also calculated by the ABCD matrix method. A deformable mirror of a continuous plate type with a diameter of 185 mm provides an adequate wave-front distribution for compensating for the wave-front aberration. The wave-front control by the deformable mirror realizes a fine linewidth of 25 mum and 18.2 mm long, corresponding to the aspect ratio of 728. The linewidth is three times the diffraction limit. The intensity distribution along the line focus is also improved.     

High‐efficiency quantum dot light‐emitting diodes with blue cadmium‐free quantum dots

We report outstanding electroluminescence properties of high‐efficiency blue cadmium‐free quantum dot light‐emitting diodes (QD‐LED). External quantum efficiency (EQE) of 14.7% was achieved for QD‐LED emitting at 428 nm. Furthermore, we developed high‐efficiency and narrow wavelength emission zinc selenide (ZnSe) nanocrystals emitting at 445 nm and achieved QD‐LED with an EQE of 10.7%. These new QDs have great potential to be used in next‐generation QD‐LED display with wide color gamut.     

Characterization of caldarchaetidylglycerol analogs, dialkyl-type and trialkyl-type, from Thermoplasma acidophilum

The structures of three kinds of phospholipids (PL-X, PL-Y, and PL-T) isolated from Thermoplasma acid-ophilum have been characterized. The core lipid of PL-Y was caldarchaeol, and that of PL-X was archaeol. The composition of the hydrocarbon chains of the PL-T core lipid was C₂₀ phytane and C₄₀ isoprenoid in a molar ratio of 2 to 1. The major molecular species of the C₄₀ isoprenoid was acyclic without the cyclopentane ring. These three kinds of intact phospholipids commonly had glycerophosphate residues as polar head groups. The structure of PL-T was characterized as trialkyl-type caldarchaetidylglycerol, PL-Y as caldarchaetidylglycerol, and PL-X as archaetidylglycerol.     

Effect of Glycosylation on the Biocatalytic Properties of Hydroxynitrile Lyase from the Passion Fruit,Passiflora edulis: A Comparison of Natural and Recombinant Enzymes

A hydroxynitrile lyase from the passion fruit Passiflora edulis (PeHNL) was isolated from the leaves and showed high stability in biphasic co‐organic solvent systems for cyanohydrin synthesis. Cyanohydrins are important building blocks for the production of fine chemicals and pharmaceuticals. Thus, to enhance production yields of PeHNL for industrial applications, we cloned and expressed recombinant PeHNL in Escherichia coli BL21(DE3) and Pichia pastoris GS115 cells without a signal peptide sequence. The aim of this study is to determine the effect of N‐glycosylation on enzyme stability and catalytic properties in microbial expression systems. PeHNL from leaves (PeHNL‐N) and that expressed in P. pastoris (PeHNL‐P) were glycosylated, whereas that expressed in E. coli (PeHNL‐E) was not. The enzymes PeHNL‐N and PeHNL‐P showed much better thermostability, pH stability, and organic solvent tolerance than the deglycosylated enzyme PeHNL‐E and the deglycosylated mutant N105Q from P. pastoris (PeHNL‐P‐N105Q). The glycosylated PeHNL‐P also efficiently performed transcyanation of (R)‐mandelonitrile with a 98 % enantiomeric excess in a biphasic system with diisopropyl ether. These data demonstrate the efficacy of these methods for improving enzyme expression and stability for industrial application through N‐glycosylation.     

LED packaging by ink‐jet microdeposition of high‐viscosity resin and phosphor dispersion

Abstract— An ink‐jet‐printing method applied to the microdeposition of high‐viscosity resin, including optimization of phosphor dispersion for light‐emitting‐diode (LED) packaging was examined for the first time. An ultrasonic ink‐jet‐printing method was used, in which ink droplets are ejected by a focused ultrasonic beam from a nozzle‐less printhead. To fabricate white LEDs, high‐viscosity phosphor‐dispersed resin was deposited to form an encapsulant dome. Two types of methods to control phosphor sedimentation for color uniformity were examined; one is heating the lead frame during the resin deposition, and the other is hydrophobic surface treatment of the lead frame base enabling the fabrication of a small encapsulant dome. For light direction control, a silicone micro lens was deposited on an encapsulant dome using the ink‐jet method. The results show that ultrasonic ink‐jet printing is an applicable technique to optimize and modify on‐demand optical characteristics of LED devices.     

Synthesis of organic-inorganic star-shaped polyoxazolines using octafunctional silsesquioxane as an initiator

Summary Hybrid star-shaped polyoxazolines having POSS core were prepared by ring-opening polymerization of 2-methyl-2-oxazoline using various octafunctional POSS as an initiator with changing the feed ratio of POSS to 2-methyl-2-oxazoline. The core-first method, which uses an active multifunctional core to initiate growth of polymer chains, was applicable to make hybrid POSS-core star-shaped polyoxazolines. The kinetic rate of the polymerization and the structures of hybrid star-shaped polyoxazolines were characterized by gas chromatography (GC) and ¹H NMR, respectively. Their thermal properties were investigated in detail by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Received: 6 November 2002 / Accepted: 20 November 2002 Correspondence to Yoshiki Chujo     

Experimental study on elemental behaviors in fluorination of nuclear spent fuel with flame reactor

Our proposed spent nuclear fuel reprocessing technology named FLUOREX is a hybrid system based on reprocessing technologies of fluorination and solvent extraction for light water reactor fuel. In the current research, we experimentally clarified solid–gas transfer behaviours of the fluorides in the FLUOREX process and identified the volatile and non-volatile compounds in the fluorination. We carried out a fluorination experiment for simulated spent nuclear fuel and solid separation from the UF₆ gas stream. The distribution ratios of fission product elements in the experimental apparatus were evaluated. Molybdenum, Te, Nb, and Ru were volatilized by fluorination and they accompanied the UF₆ gas. However, 22.9% of the Ru and 3.4% of the Nb were retained as solids in the experimental apparatus, contrary to the fact that their partial pressures in the experiment were lower than their vapor pressures. Rubidium, Sr, Zr, Ce, and Nd were completely recovered as solid fluorides, and these results agreed with the prediction based on boiling points of their fluorides. Antimony was completely recovered as a solid; nevertheless, the boiling point of antimony pentafluoride was lower than the process temperature, and that was attributed to the formation of a non-volatile antimony oxyfluoride.