Showing papers by "Nankai University published in 1990"

Maslov-type index, degenerate critical points, and asymptotically linear hamiltonian systems

Abstract: This paper introduces a Maslov-type index theory for paths in the symplectic groups, especially for the degenerate paths via rotational perturbation method, therefore gives a full classification of the linear Hamiltonian systems with continuous, periodic, and symmetric coefficients. Associating this index with each periodic solution, we establish the existence of muhiple periodic solutions of asymptotically linear Hamihonian systems.

Generalizing Born-Oppenheimer approximations and observable effects of an induced gauge field.

Abstract: By extending the Born-Oppenheimer approximation improved by Wilczek et al. to deal with separation of the spin and space coordinates of a particle in an external field, we generally discuss the direct effects of an induced gauge field and the higher-order corrections to the problem. It is shown that Bitter and Dubbers's experiment about Berry's phase is directly explained as an effect of the induced gauge potential in terms of the first-order approximation in this paper. The higher-order effects appearing in this experiment are also pointed out when the adiabatic conditions are broken.

Calanoid copepods feeding on algae and filamentous cyanobacteria: rates of ingestion, defaecation and effects on trichome length

Abstract: Etude de la capacite relative de 3 especes de Boeckella de consommer des algues et des cyanobacteries filamenteuses.Relation entre le taux d'ingestion et les variations de la biomasse des cyanobacteries et repercussion sur la taille du trichome

Real-time holographic associative memory using doped LiNbO3 in a phase-conjugating resonator.

Abstract: A real-time holographic associative memory that combines holography with phase conjugation is proposed. In the memory a type of doped LiNbO3 is used as a holographic recording medium and as a phase-conjugate mirror that provides optical feedback, thresholding, and gain. The device can store information and recall a complete image when only a portion of the stored image is input to the system. An outline of the principles and the experimental results are given, and the system’s addressing ability and selectivity are demonstrated.

A comparison of SCE test in human lymphocytes and Vicia faba: a hopeful technique using plants to detect mutagens and carcinogens.

Abstract: A comparison of the Vicia faba SCE with the human lymphocyte SCE test was made with regard to their capacity to detect mutagens. Twelve chemical agents that can induce sister-chromatid exchanges (SCEs) in both Vicia faba root tip cells and human lymphocytes were used. The results indicate that the plant SCE technique is a sensitive test for screening various chemical agents including food preservatives, pesticides and essences which may have mutagenic activity. A new simplified procedure was introduced for differential staining of sister chromatids in Vicia faba.

Comparative olfactory perception of the aggregation pheromones of Sitophilus oryzae (L.), S. zeamais (Motsch.) and S. granarius (L.), as well as the stereoisomers of these pheromones.

Abstract: Three harmful species of the genus Sitophilus (Schoenh.), differing in the extent of their adaptation to field and storage habitats, were compared with regards to olfactory perception of their aggregation pheromones and corresponding stereoisomers (fig. 1). The receptor potentials evoked by (4S,5R)-sitophilure ([4S,5R]-5-hydroxy-4-methyl-3-heptanone) in the antennal olfactory sensilla (fig. 2) of both sexes of the rice weevil (S. oryzae L.) and the maize weevil (S. zeamais Motsch.) were of similar magnitude, whereby the action of this compound as an aggregation pheromone was confirmed. Olfactory perception of (4S,5R)-sitophilure was found to be 102–103 times more intense than that of (4R,5S)-, (4R,5R)- or (4S,5S)-sitophilure in both sexes of S. zeamais (figs. 3, 4). The olfactory sensilla of female S. oryzae were at least 103 times more responsive to (4S,5R)-sitophilure than to the three stereoisomers mentioned above (fig. 5); the olfactory sensilla of male S. oryzae were ˜102 times more responsive to (4S,5R)-sitophilure than to its (4R,5S)-antipode and ˜103 times more sensitive to (4S,5R)-sitophilure than to the (4R,5R)- or (4S,5S)-enantiomer (fig. 6). The receptor potentials induced by racemic sitophilure were ˜33% and ˜25% lower than the respective receptor potentials evoked by (4S,5R)-sitophilure in both sexes of S. zeamais and S. oryzae (fig. 7). Adaptation of the olfactory receptors of S. zeamais and S. oryzae due to successive stimulation by (4S,5R)-, (4R,5S)-, (4R,5R)- and (4S,5S)-sitophilure indicates that those stereoisomers are recognized at the same receptor site. (2S,3R)-Sitophilate ([2S,3R]-1-ethylpropyl-3-hydroxy-2-methylpentanoate) elicited receptor potentials of similar magnitude in the olfactory sensilla of female and male granary weevils (S. granarius L.), which ranged from 0.5 to 1.4 mV in response to 10−3–101 μg of this stereoisomer (fig. 8). Thus, (2S,3R)-sitophilate is capable of acting as an aggregation pheromone for both sexes of the granary weevil. Moreover, (2S,3R)-sitophilate was found to be 103–104 times more active than its (2R,3S)-antipode in evoking receptor potentials in S. granarius. Pheromone perception depends thus on a high degree of chiral specificity, which is provided by the 2S,3R-configuration of the granary weevil's aggregation pheromone. The lacking olfactory perception of (2S,3R)-sitophilate by S. zeamais and S. oryzae as well as the failing response of S. granarius to (4S,5R)-sitophilure demonstrates the physiological remoteness of S. granarius from both S. oryzae and S. zeamais. Zusammenfassung Vergleichende Wahrnehmung der Aggregationspheromone und deren Stereoisomere an den Fuhlerriechhaaren weiblicher und mannlicher Reiskafer (Sitophilus oryzae L.), Maiskafer (S. zeamais Motsch.) sowie Kornkafer (S. granarius L.) Drei verbreitete, schadliche Sitophilus-Arten (Curculionidae, Coleoptera) mit unterschiedlichem Anpassungsgrad an Feld- und Speicherbiotope wurden auf das Wahrnehmungsvermogen ihrer Aggregationspheromone und deren Stereoisomere (Abb. 1) mittels elektrophysiologischer Technik untersucht. Abgestufte Mengen (10−2–101 μg) von (4S,5R)-Sitophilur ([4S,5R]-5-Hydroxy-4-methyl-3-heptanon) bewirkten ahnlich hohe Rezeptorpotentiale an den Fuhlerriechhaaren (Abb. 2) weiblicher sowie mannlicher Maiskafer (0.95–2.05 mV) und Reiskafer (1.1–1.8 mV), so das die Voraussetzung fur die Wirkung dieses korpereigenen Stoffes als Aggregationspheromon erfullt ist (Abb. 3–6). (4S,5R)-Sitophilur, das Aggregationspheromon von S. zeamais und S. oryzae, wurde von weiblichen und mannlichen S. zeamais 102–103fach starker wahrgenommen als die (4R,5S)-, (4R,5R)- oder (4S,5S)-Stereoisomere des Lockstoffes (Abb. 3, 4). Die Fuhlerriechhaare der weiblichen S. oryzae reagierten mindestens 103fach empfindlicher auf (4S,5R)-Sitophilur als auf dessen (4R,5S)-, (4R,5R)-und (4S,5S)-Stereoisomere (Abb. 5), wahrend die Fuhlerriechhaare der mannlichen S. oryzae ˜102fach starker auf (4S,5R)-Sitophilur als auf das antipode (4R,5S)-Sitophilur und ˜103fach starker auf (4S,5R)-Sitophilur als auf das (4S,5S)- und (4R,5R)-Enantiomerenpaar ansprachen (Abb. 6). Racemisches Sitophilur ([4S,5R]: [4R,5S]: [4R,5R]: [4S,5S] = 1:1:1:1) bewirkte bei beiden Geschlechtern von S. zeamais und S. oryzae Rezeptorpotentiale, die ˜33% bzw. ˜25% niedriger als die entsprechenden, von (4S,5R)-Sitophilur hervorgerufenen, Rezeptorpotentiale waren (Abb. 7). Da aufeinanderfolgende, gleichstarke Reize von (4S,5R)-, (4R,5S)-, (4R,5R)- und (4S,5S)-Sitophilur auf die Fuhlerriechhaare von S. zeamais und S. oryzae die Adaptation deren olfaktorischer Rezeptoren verursachte, kann man annehmen, das die vier Stereoisomere an der gleichen Rezeptorstelle erkannt werden. Das — von Kornkafermannchen abgegebene — (2S,3R)-Sitophilat ([2S,3R]-1-Athylpropyl-3-hydroxy-2-methylpentanoat) loste an den Fuhlerriechhaaren weiblicher und mannlicher S. granarius ahnlich hohe Rezeptorpotentiale aus, die bei abgestuften Reizmengen von 10−3 bis 100 μg 0.5–1.4 mV betrugen (Abb. 8). Demnach wurde gefolgert, das (2S,3R)-Sitophilat bei beiden Geschlechtern von S. granarius als Aggregationspheromon wirken kann. Aufgrund der von letzterem an mannlichen und weiblichen Kornkafern hervorgerufenen Rezeptorpotentiale, war (2S,3R)-Sitophilat 103-104fach wirksamer als das enantiomere (2R,3S)-Sitophilat. Somit beruht die Pheromonwahrnehmung auf einer hohen chiralen Spezifitat, die durch die 2S,3R-Konfiguration des Aggregationspheromons gewahrleistet ist. Die Unfahigkeit von S. zeamais und S. oryzae (2S,3R)-Sitophilat geruchlich wahrzunehmen sowie das fehlende Riechvermogen von S. granarius fur (4S,5R)-Sitophilur veranschaulichen die physiologische Verschiedenheit des Maiskafers und des Reiskafers einerseits sowie des Kornkafers andererseits.

New hierarchies of knot polynomials from topological Chern-Simons gauge theory

Abstract: In this Letter, we report on a study of the expectation values of Wilson loops in D=3 topological Chern-Simons theory associated with the fundamental representation of the simple Lie algebras SO(n) and Sp(n). The skein relations satisfied by these expectation values are derived by conformal field-theory techniques. New hierarchies of invariant polynomials for knots in S 3 can be derived from these relations (at least) up to ten crossings. The N=3 Akutsu-Wadati polynomials are a special case with G=SO(3). The expectation value of the Wilson loops for a couple of simple unknotted circles is identified to the Weyl character.

Periodic solutions of superquadratic Hamiltonian systems with bounded forcing terms

Abstract: On etudie l'existence et la multiplicite des solutions periodiques pour le systeme hamiltonien z=Ĥ z (t,z) ou Z:R→R 2N , z=dz/dt, J=(o/J −J/o) J etant la matrice identite dans R N

Heald frame for looms

Abstract: A heald frame, constructed to have upper and lower framestaves and left and right side stays coupled to one another, the coupling between the framestaves and the side stays adjustable to increase or decrease the distance between the upper framestave and the lower framestave. The heald frame is also able to change the distance between upper and lower carrier rods, which are fixed to the upper and lower framestaves respectively, thereby permitting the adjustment of the distance between the ends of a multiplicity of healds which span a distance between the upper and lower carrier rods. The coupling is made from a side stay with a jointing convex part capable of being adjustably coupled to a holder. The adjustable jointing convex part and the holder, which are mounted together in the framestaves, are adapted to be fixed in a selected position. This results in the ability to vertically adjust the framestave in relation to the side stay and in course, the distance between cooperating carrier rods and the ends of healds carried thereon.

Amplitude compensated matched filters using circular harmonic expansion and a Mellin transform.

Abstract: The new techniques of amplitude compensated matched filtering using circular harmonic expansion and a Mellin transform are presented. These techniques yield much better discrimination and sharper autocorrelation peaks compared with the classical matched spatial filtering. Aside from these advantages, the amplitude compensated circular harmonic expansion matched filtering can also yield rotation invariance, and the amplitude compensated Mellin transform matched filtering can yield scale invariance. By computer simulation, we have verified the unique advantages of the new methods. We also provide 3-D graphs of autocorrelation and cross correlation.

Computer-assisted optimization of selectivity (mobile phase, pH, and ion concentration) in high-perfomance liquid chromatography

Abstract: A computer-assisted method is presented for optimization of mobile phase composition in reverse-phase and normal-phase HPLC. The method is based on window diagrams, but only three preliminary tests are required. The method is successfully applied to two examples and there is good agreement between predicted and experimental results. Optimal values for ion concentration and pH in ion chromatography from a published optimization method are comparared to values calculated using the computer-assisted method presented in this paper. The same results are obtained, but the method presented here is simpler and faster than the previously published one

Forced Oscillations for the Triple Pendulum

Abstract: Publisher Summary This chapter discusses the global periodic solutions for the planar triple pendulum There are additional periodic orbits for special arrangements of the parameter values of the system The periodic solutions found have, in general, small periods and are of oscillatory character The idea of proof is based on a well-known variational principle for which the critical points are the required periodic solutions The chapter presents the proof of the existence of eight periodic orbits for the planar triple pendulum problem under a few conditions

The effect of weak gravitational force on Brownian coagulation of small particles

Abstract: The coagulation rate of a dilute polydisperse suspension of particles is considered for small Peclet number, which provides a measure of the ratio of the relative gravity-induced motion to Brownian motion between two rigid spheres. In particular, a fourterm expansion for the dimensionless coagulation rate (Nusselt number) as function of the Peclet number is developed by making use of a singular perturbation method. In the limit of the radius of one of the two spheres becoming small, the result agrees with Acrivos & Taylor's (1962) work on mass transfer to spheres at small Peclet number.

Infrared absorption study of OH- in LiNbO3:Mg and LiNbO3:Mg:Fe crystals

Abstract: Etude de l'absorption IR de OH − dans LiNbO 3 :Mg:Fe avec divers rapports atomiques Li/Nb et differentes concentrations en Mg. Comparaison des resultats a ceux de la bande d'absorption de OH − dans LiNbO 3 :Mg. La structure de la bande d'absorption de OH − est correlee a la composition et a la structure de defaut dans les cristaux de LiNbO 3 dopes

Boson Realization of Representations for Quantum Groups and Its Differential Correspondence in Bargmann Space

Abstract: By constructing the q-analogue of the Heisenberg-Weyl algebra in terms of usual creation and annihilation operators of boson states in the Fock space, the boson realization method recently suggested[7-11] is generalized to obtain a class of representations of quantum group in the Fock space. The q-deformed differential realization of quantum groups proposed by Alvarez-Gaume is derived by making use of the boson realization in this paper.

Studies of absorption spectra and the photovoltaic effect in LiNbO3:Mg:Fe crystals

Abstract: The absorption spectra, photoconductivities and photovoltaic currents of LiNbO3:Fe crystals with different Mg doping levels and Li/Nb ratios in the oxidized state have been investigated at room temperature. The Fe2+ ions in LiNbO3:Mg:Fe with Mg content above a critical value are more easily oxidized than in crystals with Mg content below a critical value. The photoconductivity of LiNbO3:Mg:Fe crystals with Mg content above a critical value is one order of magnitude higher than those with Mg content below a critical value, however, the photovoltaic current of the former is one order of magnitude lower than the latter. The differences are postulated to be due to different sites of Fe in these two classes of crystals.