NMR and Structural and Conformational Features of 2′-Hydroxychalcones and Flavones

New 2′-hydroxychalcone and flavone derivatives have been synthesised. Their [¹H] and [¹³C] NMR spectra were assigned by the application of COSY and HETCOR experiments and allowed the discussion of some structural aspects. It was shown on the basis of NOE experiments some configurational and conformational features of both type of compounds.     

Laser ultrasonic generation and optical detection and processing

History,present situation and importancy of the laser-generatedultrasonic technique arc presented.Basic principles and some experimentalresults of laser ultrasonic generation and optical detection and processing arediscussed.Several problems about applying this technique to NDT are also dis-cussed in this paper.     

Research and Development of SWITRIM Code and Its Applications

The ftrst numerical simulation code package WITRIM has been developed to calculate the tritium inventory distribution and time-evolution in all sub-systems of FEB fusion reactor. The applications during recent six years indicate that it is reasonable and fully admitted by colleagues abroad. Some creative papers with new concept are published. For instance, we first time pointed out a new phenomenon of ＂tritium well depth and tritium well time＂ during the fusion reactor start-up phase. This is somewhat similar to, but quite different from the ＂iodine well depth and iodine well time＂ poisoning problem during restart-up process of a fission reactor. The authors not only proposed but also numerically solved this new phenomenon. The combination of the SWITRIM code package, user＇s guide, and application example are briefly introduced in this article.     

Structure and stability of neutral and cationic AlnO clusters

In this paper various structural possibilities for AlnO neutral and cationic isomers were investigated by using the B3LYP/6-311G（3df） method. Calculations of this paper predicted the existence of a number of previously unknown isomers. The stabilities of the AlnO （n = 2 - 7） clusters with even n are greater than those with odd n, however the stabilities Of cationic ions have the opposite odd-even alternation. The mass spectra observations of Al17O^＋ and Al19O^＋ ions support our theoretical predictions on their stabilities.     

Preparation and Luminescent Properties of ZnO Microrods and Microtubes

Hexagonal ZnO microrods and sub-microrods have been prepared through thermal decomposition of an equimolar (0.1 M) aqueous solution of Zn(NO3)2.4H20 and (CH2)6N4 a~t 90~C for different times (10-46h). The microrods were transformed into hollow hexagonal ZnO microtubes when the growth time reached 46 h. The Raman spectra and the photoluminescent (PL) spectra were measured. The PL spectra of microrods consist of two strong narrow near-UV bands at 380 nm and 400 nm assigned to free exciton emission and exciton-exciton collision, respectively.The PL spectrum of ZnO microtubes show only one peak in the near-UV region with peak located at 380nm with FWHM of about 20nm assigned to free exciton emission. When the growth time increased, the peak intensity of near-UV band decreased.     

Mixing and decays of ρ- and ω-mesons

Isospin-violating mixing of ρ- and ω-mesons is reconsidered in terms of propagators. Its influence on various pairs of (ρ,ω)-decays to the same final states is demonstrated. Some of them, (ρ,ω)↦π⁺π^- and (ρ,ω)↦πγ, have been earlier discussed in the literature, others (e.g., (ρ,ω)↦ηγ and (ρ,ω)↦e ⁺ e ^-) are new in this context. Changes in partial widths for all the decay pairs are shown to be correlated. The set of present experimental data, though yet inconclusive, provides some limits for the direct (ρω)-coupling and indirectly supports enhancement of ρ↦πγ in comparison with ρ^±↦π^±γ, though not so large as in some previous estimates. Received: 16 September 2002 / Accepted: 23 September 2002 / Published online: 4 February 2003 RID="a" ID="a"e-mail: azimov@pa1400.spb.edu Communicated by V.V. Anisovich     

Effects of creatine and β-guanidinopropionic acid and alterations in creatine transporter and creatine kinases expression in acute seizure and chronic epilepsy models

Background  

In order to confirm the roles of creatine (Cr) in epilepsy, we investigated the anti-convulsive effects of Cr, creatine transporter (CRT) and creatine kinases (CKs) against chemical-induced acute seizure activity and chronic epileptic seizure activity.     

Radial excitations ofp- and π-mesons and their strong decays

Radial (L=0) excitations ofp- and π-mesons are considered in the framework of the quark model. The experimentally observed statesρ′ (1220) andρ″ (1560) are identified with the first and second radial excitations of thep-meson. Within the relativistically generalized model of spontaneous production of a \(q\bar q\) pair from vacuum we explain the dominant (ρ′ →ωπ;ρ″ →ω2π) modes of strong decays of these resonances and find nondominant modes (ρ ′ 2π;ρ″ →ωπ) to be suppressed. An estimation is given for masses of analogous excitations of the pion and partial widths of their decays.     

Photovoltaic and Electroluminescence Bifunctional Devices with Starburst Amine and Rare-Earth-Complexes

We fabricate the organic photovoltaic （PV） devices, in which 4,4＇,4＂-tris-（2-methylphenylphenylamino）triphenylamine （m-MTDATA） and rare earth （RE） （dibenzoylmethanato）a（bathohenanthroline） （RE（DBM）abath） （RE = Nd or Pr） are used as electron donor and acceptor, and investigate their PV properties. The PV diode fabricated in the optimum processing conditions shows the open-circuit voltage of 1.91 V, short-circuit current of 0.1 mA/cm^2, fill factor of 0.38, and the overall power conversion efficiency of 1.9% when it is irradiated under UV light （4 m W/cm^2）. The photocurrent density exhibits an increase of 20% at least when a very thin LiF layer is inserted between the RE-complexes and the A1 cathode. A strong electroluminescence from the interface is also observed and the maximum luminance of a yellow emission resulted from the exciplex is 580 cd/m^2 at 17 V bias.     

Fluorescein and Phenolphthalein—Correlation of Fluorescence and Photoelectric Properties

Two phthalein dyes in aqueous polyvinyl alcohol solutions of pH 8.5 have been investigated: fluorescein and phenolphthalein. Competitive pathways of deactivation of their energetically excited states have been followed by the use of spectroscopic and photoelectric techniques. Radiative, nonradiative, and charge separation processes followed by electron transfer have been measured by absorption, fluorescence, and photoacoustic spectroscopy accompanied by photovoltage/photocurrent generation in a photoelectrochemical cell. It is shown that, despite their being only a slight difference in molecular structure between the two dyes, their spectral as well as photoelectric behavior is significantly different.     

Continuum and discretum—Unified field theory and elementary constants

Unitary field theories and SUPER-GUT theories work with an universal continuum, the structured spacetime of R. Descartes, B. Spinoza, B. Riemann, and A. Einstein, or a (Machian ^(1–3) ) structured vacuum according the quantum theory of unitary fields (Dirac, ^(4,5) and Heisenberg ^(6–8) ). The atomistic aspect of the substantial world is represented by the fundamental constants which are invariant against all transformations and which depend on nothings (Planck ^(9–11) ). A satisfactory unitary theory has to involve these constants like the mathematical numbers. Today, Planck's conception of the three elementary constants , c, and G may be the key to general relativistic quantum field theory like unitary theory. However, the elementary constants are a question of measurement-theory, also.According to Popper's theory ^(12–16) of induction, such unitary theories are universal explaining theories. The fundamental constants involve the complementarity between the universal statements in unitary theory and the basic statements in the language of classical observables.     

Growth and characterization of oriented CdSe nanobelts and nanorods

Oriented CdSe nanobelts and nanorods were grown successfully on GaAs and Si substrates by metal organic chemical vapor deposition. The thickness of Au film coated on the substrate plays an important role in determining the orientation, size, and density of these one-dimensional CdSe nanostructures. Preferred orientation was observed for nanostructures grown on the GaAs substrate coated with thick Au film, but not for the nanostructures grown on the Si substrate. Photoluminescence, transmission electron microscope, and X-ray diffraction measurements show that the CdSe nanostructures could have either wurtzite or zinc-blende structures, and there are more nanostructures with wurtzite structure than with zinc-blende structure.     

Probability Description and Entropy of Classical and Quantum Systems

Tomographic approach to describing both the states in classical statistical mechanics and the states in quantum mechanics using the fair probability distributions is reviewed. The entropy associated with the probability distribution (tomographic entropy) for classical and quantum systems is studied. The experimental possibility to check the inequalities like the position–momentum uncertainty relations and entropic uncertainty relations are considered.     

Loop and Path Spaces and¶Four-Dimensional BF Theories:¶Connections, Holonomies and Observables

We study the differential geometry of principal G-bundles whose base space is the space of free paths (loops) on a manifold M. In particular we consider connections defined in terms of pairs (A,B), where A is a connection for a fixed principal bundle P(M,G) and B is a 2-form on M. The relevant curvatures, parallel transports and holonomies are computed and their expressions in local coordinates are exhibited. When the 2-form B is given by the curvature of A, then the so-called non-abelian Stokes formula follows. For a generic 2-form B, we distinguish the cases when the parallel transport depends on the whole path of paths and when it depends only on the spanned surface. In particular we discuss generalizations of the non-abelian Stokes formula. We study also the invariance properties of the (trace of the) holonomy under suitable transformation groups acting on the pairs (A,B). In this way we are able to define observables for both topological and non-topological quantum field theories of the BF type. In the non-topological case, the surface terms may be relevant for the understanding of the quark-confinement problem. In the topological case the (perturbative) four-dimensional quantum BF-theory is expected to yield invariants of imbedded (or immersed) surfaces in a 4-manifold M. Received: 28 March 1998 / Accepted: 12 September 1998     

B?cklund Transformation and Solutions for the Long-Wave and Short-Wave Resonance Equations and Their Extending System

By using Painlevé analysis, we derive the Backlund transformation for the longwave and short-wave resonance equations and their extending systems. Then we take some constraints of the B?ckJund transformation and find some solutions.     

Helicon and Alfvén wave propagation in non-magnetic semiconductors and semi-metals: Active and passive waves

It was pointed out in 1960 that metals and semiconductors can support low frequency electromagnetic excitations in the presence of a magnetic field. We now feel that it is an appropriate time to discuss some of the progress made, over the last decade, in understanding and using this novel phenomenon. Naturally the field has grown quite rapidly and it would clearly be a Herculean task to review every aspect of it in other than a superficial manner. We have therefore chosen to discuss only semiconductors and semi-metals. This choice is dictated to us partly by the fact that magneto-plasma effects in metals have been reviewed from time to time but mainly by the fact that magneto-plasma effects in semiconductors have never been previously reviewed.

Of course the term ‘magneto-plasma’ covers a great deal of activity so we have decided to choose a theme which links the beginnings of the subject to the present day. This theme is that of helicon and Alfvén wave propagation.

We have produced a background of theory against which the nature of helicon and Alfvén waves can be readily understood. This background theory can also be used as a starting point for investigations of other plasma effects beyond the scope of this review.

Some considerable attention is paid to waves in active systems, i.e. systems possessing a pool of energy arising from the application of an external electric field. Such systems, while of basic physical interest, are also of technical interest from a solid-state device viewpoint. The possibility of transverse wave instabilities occurring in active systems is discussed and a review of the criteria for labelling the types of instability is presented. As an example of the use of these techniques we have attempted to correlate the high electric field microwave emission from indium antimonide with a helicon-based instability.

The theoretical work is set in perspective by the inclusion of discussions of the experimental work in the appropriate areas. We have also included a brief review of experimental observations of microwave emission from indium antimonide and the proposed mechanisms, other than helicon instability, which may account for it.     

Classical and quantum statistical mechanics in one and two dimensions: Two-component Yukawa — and Coulomb systems

We estimate the canonical and grand canonical partition function in a finite volume and prove stability and existence of the thermodynamic limit for the pressure of two component classical and quantum systems of particles with charge ± interacting via two body Yukawa — or Coulomb forces. In the case of Coulomb forces we require neutrality. For the classical system in two dimensions there exists a critical temperatureT _c at and below which the system collapses. For the classical Yukawa system the correlation functions exist for arbitrary fugacity and the general structure of the pure phases can be analyzed completely.     

Spin and valley half metal induced by staggered potential and magnetization in siliceneSpin and valley half metal induced by staggered potential and magnetization in siliceneSpin and valley half metal induced by staggered potential and magnetization in silicene

We investigate the electron transport in silicene with both staggered electric potential and magnetization; the latter comes from the magnetic proximity effect by depositing silicene on a magnetic insulator. It is shown that the silicene could be a spin and valley half metal under appropriate parameters when the spin-orbit interaction is considered; further, the filtered spin and valley could be controlled by modulating the staggered potential or magnetization. It is also found that in the spin-valve structure of silicene, not only can the antiparallel magnetization configuration significantly reduce the valve-structure conductance, but the reversing staggered electric potential can cause a high-performance magnetoresistance due to the spin and valley blocking effects. Our findings show that the silicene might be an ideal basis for the spin and valley filter analyzer devices.     

Enhancement of Piezoelectric and Dielectric Properties and Macroscopic Relaxation of Charge and Field Response in 0–3 Ceramic-Pore Composites: Theory and Experiment

In this work, we have theoretically and experimentally described the dielectric and piezoelectric properties of ceramic-based lead zirconate–titanate composites that have a 0–3 bond. Based on the proposed model, the frequency dependences of the dielectric and piezoelectric response have been determined theoretically and experimentally. The influence of the Maxwell–Wagner relaxation and the effective parameter approximation on the physical properties of disordered objects of statistical mixture have been studied. The distribution functions of the times of intercomponent relaxation in the piezoceramic–pores composite system and the concentration dependences of the effective field responses have been determined. The theoretical and experimental results obtained have been compared.