3,854 research outputs found
Technique for manufacturing nickel electrodes
A method of manufacturing nickel electrodes distinctive for its use of a composite material for the electrode made up of nickel compound, electrode material, cobalt in metal form or cobalt in compound form is investigated. The composite is over-discharged (same as reverse charging) in an alkaline solution. After dealkalization, synthetic resin adhesive is added and the electrode is formed. Selection of the cobalt compound is made from a group consisting of cobalt oxide, cobalt hydroxide, cobalt carbonate and cobalt sulfate. The method upgrades plate characteristics by using an active material in a non-sintered type nickel electrode, which is activated by electro-chemical effect
Phylogenetic relationships among Aegilops-Triticum species based on sequence data of chloroplast DNA
ENZYMIC EXCHANGE OF LEUCINE BETWEEN DIFFERENT COMPONENTS OF LEUCINE ACCEPTOR RNA IN ESCHERICHIA COLI
Ground ant fauna in a Bornean dipterocarp forest
The ant fauna of the forest floor was studied in a Bornean lowland dipterocarp forest using honey baits. A total of 51 species belonging to 23 genera was collected from 90 (45 daytime + 45 night) baits set on the ground surface and 90 (45 daytime + 45 night) baits set on tree trunks at 0.5-1.0 m above the ground. Collected species represented only 22% of the total ant species so far known from this area using a combination of several collection techniques. Although some species (Pheidole spp., Camponotus gigas, Lophomyrmex longicornis, etc.) are more frequently attracted than others, the frequency occurrence in these species was much lower than in the dominant species in warm temperate evergreen forests in Japan. Baits put on the ground surface attracted more ant species than those on tree trunks (35 vs. 25 spp.), and only 9 species were common to both types of habitat. Daytime and night baits attracted nearly the same number of ant species (34 vs. 31), only 14 being common to both time zones. Various aspects of ant diet and activity pattern are discussed.ArticleRaffles Bulletin of Zoology. 44(1): 253-262(1996)journal articl
Effects of tape covering and vine vigor on development of surface callus in girdle of grapevine
The effects of vine vigor (shoot growth) and covering the girdle surface with plastic tape on the development of a surface callus (SC) in the girdle of grapevine were studied by histological observation. The SC was formed in a tape-covering treatment but was not formed unless the girdle surface was covered with plastic tape (exposing treatment). Histological observation revealed that in the tape-covering treatment, callus cells developed mainly from the ray parenchyma cells on the girdle surface 2 days after girdling (DAG), leading to the formation of the SC, which grew and filled the girdle portion by 7 DAG. When 16 vines were divided into three categories based on scaffold branch length, vines with 7.5 m scaffold branches developed shorter shoots with smaller internode diameters than did vines with 4.5 and 6.0 m scaffold branches. In vines with 7.5 m scaffold branches, the SC covered a smaller area of the girdle surface than in vines with 4.5 and 6.0 m scaffold branches. The length and diameter of the shoot were significantly correlated (r2 = 0.75** and 0.70**, respectively) with the ratio of the girdle area covered by the SC to the whole girdle area (SC covering ratio). These results show that the SC originates mainly from the ray parenchyma cells and that SC development is strongly affected by vine vigor. Consequently, to ensure SC development, girdling should be done by tape covering in vines with shoot diameters larger than 8 mm.
Pressure-induced phase transition and bi-polaronic sliding in a hole-doped Cu_2O_3 ladder system
We study a hole-doped two-leg ladder system including metal ions, oxygen, and
electron-lattice interaction, as a model for Sr_{14-x}Ca_xCu_{24}O_{41-\delta}.
Single- and bi-polaronic states at 1/4-hole doping are modeled as functions of
pressure by applying an unrestricted Hartree-Fock approximation to a multiband
Peierls-Hubbard Hamiltonian. We find evidence for a pressure-induced phase
transition between single-polaron and bi-polaron states. The electronic and
phononic excitations in those states, including distinctive local lattice
vibrational modes, are calculated by means of a direct-space Random Phase
approximation. Finally, as a function of pressure, we identify a transition
between site- and bond-centered bi-polarons, accompanied by a soft mode and a
low-energy charge-sliding mode. We suggest comparisons with available
experimented data
The table mountain 8-mm-wavelength interferometer
The system components, performance, and calibration of two element radio interferometer operating at 8.33 mm wavelength are discussed. The interferometer employs a 5.5 m and a 3 m diameter antenna on an east-west baseline of 60 or 120 m, yielding fringe spacings at transit of 28 or 14 in. respectively. The broad intermediate frequency bandpass of 100 to 350 MHz and the system noise temperature of 500 K provide high sensitivity for the measurement of continuum sources. The interferometer has been used for high resolution studies of the planets and the Sun, and it is currently being adapted to study solar flare emissions at high spatial and time resolution
Jacobson generators of the quantum superalgebra and Fock representations
As an alternative to Chevalley generators, we introduce Jacobson generators
for the quantum superalgebra . The expressions of all
Cartan-Weyl elements of in terms of these Jacobson generators
become very simple. We determine and prove certain triple relations between the
Jacobson generators, necessary for a complete set of supercommutation relations
between the Cartan-Weyl elements. Fock representations are defined, and a
substantial part of this paper is devoted to the computation of the action of
Jacobson generators on basis vectors of these Fock spaces. It is also
determined when these Fock representations are unitary. Finally, Dyson and
Holstein-Primakoff realizations are given, not only for the Jacobson
generators, but for all Cartan-Weyl elements of .Comment: 27 pages, LaTeX; to be published in J. Math. Phy
Absorption-free optical control of spin systems:the quantum Zeno effect in optical pumping
We show that atomic spin motion can be controlled by circularly polarized
light without light absorption in the strong pumping limit. In this limit, the
pumping light, which drives the empty spin state, destroys the Zeeman coherence
effectively and freezes the coherent transition via the quantum Zeno effect. It
is verified experimentally that the amount of light absorption decreases
asymptotically to zero as the incident light intensity is increased.Comment: 4 pages with 4 figure
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