Effect of oxide in nickel-based composite anodes on current efficiency for NF3 formation and current loss caused by nickel dissolution in molten NH4F·2HF

Nickel-oxide composites such as Ni-Co₃O₄, Ni-MnO₂, Ni-Ag₂O, Ni-Y₂O₃, Ni-La₂O₃, Ni-Nd₂O₃, and Ni-Sm₂O₃ systems were prepared from mixture of nickel and oxide powders by hot isostatic pressing (HIP). Ratios of oxide in the nickel-oxide composite were 2, 5, and 10 mol%. Anode gas evolved at every nickel-based composite electrode was composed of N₂, O₂, NF₃, N₂F₂, N₂F₄, and N₂O, and its composition was almost the same as that on a nickel sheet electrode. Current efficiency for NF₃ formation on Ni-Y₂O₃ and Ni-La₂O₃ composite anodes were almost the same as that on the nickel anode, whereas that on Ni-Co₃O₄ composite anode was very small compared with that on the nickel sheet anode. In the cases of the Ni-Co₃O₄, the Ni-MnO₂, and the Ni-Ag₂O composite anodes, the current efficiency for NF₃ formation decreased with increase in the oxide concentration in the composite anodes.Current losses caused by nickel dissolution of the Ni-La₂O₃, the Ni-MnO₂, and the Ni-Ag₂O composite anodes were small compared with that of the nickel sheet anode, while that of the Ni-Co₃O₄ composite anode was very large compared with that of the nickel sheet anode. SEM observation revealed that the surfaces of the Ni-La₂O₃, the Ni-MnO₂, and the Ni-Ag₂O composite anodes after electrolysis were covered with a dense oxidized layer with a few pores and/or some defects. Anode potential during electrolysis indicated that the oxidized layer formed on the Ni-La₂O₃ composite anode has the higher electric conductivity, presumably because of presence of both LaF₃ and NiO_1+x (0 ≤ x < 0.5) in it.     

Computing quadratic entropy in evolutionary trees

We note here that quadratic entropy, a measure of biological diversity introduced by C.R. Rao, is a variant of the weighted Wiener index, a graph invariant intensively studied in mathematical chemistry. This fact allows us to deduce some efficient algorithms for computing the quadratic entropy in the case of given tip weights, which may be useful for community biodiversity measures. Furthermore, on ultrametric phylogenetic trees, the maximum of quadratic entropy is a measure of pairwise evolutionary distinctness in conservation biology, introduced by S. Pavoine. We present an algorithm that maximizes this quantity in linear time, offering a significant improvement over the currently used quadratic programming approaches.     

DNA sequence of the beta-isopropylmalate dehydrogenase gene and phylogenetic analysis of the yeast Saccharomyces exiguus Yp74L-3

The beta-isopropylmalate dehydrogenase (LEU2) gene from a homothallic wild-type yeast, Saccharomyces exiguus Yp74L-3, was analyzed to estimate the phylogenetic position of this strain in yeasts. The beta-isopropylmalate dehydrogenase gene of Yp74L-3 was first isolated as a clone complementing the leu2 mutation of Saccharomyces cerevisiae, and then confirmed to complement the haploid leu2 mutant derived from strain Yp74L-3 through genetic transformation. The nucleotide sequence of the cloned DNA revealed an open reading frame (ORF) encoding the beta-isopropylmalate dehydrogenase composed of 365 amino acids. The beta-isopropylmalate dehydrogenase coding sequence from the Yp74L-3 strain displayed 76.7% similarity to that of S. cerevisiae. Candidates for a UAS and a TATA-box in the 5'-upstream region and for a poly-A attachment site in the 3'-downstream region were found. A phylogenetic tree constructed from the nucleotide sequences of the beta-isopropylmalate dehydrogenase coding regions revealed that Yp74L-3 is located between S. cerevisiae and the Kluyveromyces yeasts. The LEU2 gene cloned from Yp74L-3 will serve as an effective genetic marker for constructing the transformation system in S. exiguus Yp74L-3.     

A configurable DRAM macro design for 2112 derivative organizationsto be synthesized using a memory generator

This paper describes a DRAM macro design from which 2112 configurations up to 32 Mb can be synthesized using a memory generator. The memory generator automatically creates the layout of a DRAM macro in accordance with specification inputs such as memory capacity, address count, bank count, and I/O bits count. An expandable floor layout scheme achieves the macro size comparable to that of handicraft-designed DRAM. The memory generator can customize a configurable redundancy scheme for various macro configurations. Unified testing circuits make it possible to test DRAM macros with more than 500 interface pins in a direct-memory-access mode with 33 test pads. Up to four macros on the same chip can be tested with them. Test chips with 4-Mb DRAM and with 20-Mb DRAM fabricated with 0.35-μm technology showed 150-MHz operation     

In vitro anti-human immunodeficiency virus (HIV) activities of transition state mimetic HIV protease inhibitors containing allophenylnorstatine

Transition state mimetic tripeptide human immunodeficiency virus (HIV) protease inhibitors containing allophenylnorstatine [(2S,3S)-3-amino-2-hydroxy-4-phenylbutyric acid] were synthesized and tested for activity against HIV in vitro. Two compounds, KNI-227 and KNI-272, which were highly potent against HIV protease with little inhibition of other aspartic proteases, showed the most potent activity against the infectivity and cytopathic effect of a wide spectrum of HIV strains. As tested in target CD4+ ATH8 cells, the 50% inhibitory concentrations of KNI-227 against HIV type 1 LAI (HIV-1LAI), HIV-1RF, HIV-1MN, and HIV-2ROD were 0.1, 0.02, 0.03, and 0.1 microM, respectively, while those of KNI-272 were 0.1, 0.02, 0.04, and 0.1 microM, respectively. Both agents completely blocked the replication of 3'-azido-2',3'-dideoxythymidine-sensitive and -insensitive clinical HIV-1 isolates at 0.08 microM as tested in target phytohemagglutinin-activated peripheral blood mononuclear cells. The ratios of 50% cytotoxic concentrations to 50% inhibitory concentrations for KNI-227 and KNI-272 were approximately 2,500 and > 4,000, respectively, as assessed in peripheral blood mononuclear cells. Both compounds blocked the posttranslational cleavage of the p55 precursor protein to generate the mature p24 Gag protein in stably HIV-1-infected cells. The n-octanol-water partition coefficients of KNI-227 and KNI-272 were high, with log Po/w values of 3.79 and 3.56, respectively. Degradation of KNI-227 and KNI-272 in the presence of pepsin (1 mg/ml, pH 2.2) at 37 degrees C for 24 h was negligible. Current data warrant further careful investigations toward possible clinical application of these two novel compounds.     

Algorithm library based on algorithmic cyberFilms

A library of algorithms developed as algorithmic cyberFilms is presented. Algorithmic cyberFilms are a new type of software components for presentation, specification/programming and automatic code generation of computational algorithms. The algorithmic cyberFilm format is implemented as a set of multimedia frames (and scenes), and each component is represented by frames of algorithmic skeletons representing dynamical features of an algorithm, by frames of integrated view providing static features of the algorithm in a compact format, and by corresponding template codes supporting the program generation. We developed a library which is a collection of basic and advanced algorithms taught at universities, including computation on grids, trees and graphs. In this paper, we present basic constructs of visual languages which are used for representing cyberFilms as well as for demonstrating the library components. We also provide a general overview of the library and its features. In addition, we discuss results of experiments which were conducted to verify the usability of the library components and their usefulness in education.     

Experimental investigation of stabilization and emission characteristics of ammonia/air premixed flames in a swirl combustor

Ammonia is a possible candidate for use as a hydrogen energy carrier as well as a carbon-free fuel. In this study, flame stability and emission characteristics of swirl stabilized ammonia/air premixed flames were experimentally investigated. Results showed that ammonia/air premixed flame could be stabilized for various equivalence ratios and inlet flow velocity conditions in a swirl burner without any additives to enhance the reaction of ammonia even though the laminar burning velocity of ammonia is very slow. The lean and rich blowoff limits were found to be close to the flammability limits of the ammonia flame. In addition, emission characteristics were investigated using an FTIR gas analyzer. The NO concentration decreased and ammonia concentration increased under rich conditions. Moreover, it was found that there is an equivalence ratio in rich condition in which NO and ammonia emission are in the same order.     

Dynamically shift-switched dataline redundancy suitable for DRAMmacro with wide data bus

A novel dataline redundancy suitable for an embedded DRAM macro with wide data bus is presented. This redundancy reduces the area required for spare cells from 6 to 1.6% of the area required for normal cells and improves chip yield from 50 to 80%. In addition, it provides a high-speed data path. An embedded DRAM macro adopting the redundancy achieves 200-MHz operation and provides 51.2-Gbit/s bandwidth. It has been fabricated with 0.25-μm technology