Switching the light emission of (4-biphenylyl)phenyldibenzofulvene by morphological modulation: crystallization-induced emission enhancement

(4-Biphenylyl)phenyldibenzofulvene is weakly luminescent in the amorphous phase but becomes highly emissive upon crystallization; this unusual crystallization-induced emission enhancement effect allows its emission to be repeatedly switched between dark and bright states by fuming-heating and heating-cooling processes.     

Asymmetric total synthesis of (-)-indicol by a carbene cyclization-cycloaddition cascade strategy

The first total synthesis of a secodolastane, (-)-indicol, has been accomplished. The key reaction is a rhodium(II)-mediated carbene cyclization-cycloaddition cascade, by which the core bicyclo[5.4.0]undecane skeleton was assembled. In this one-pot reaction, a domino series of transformations resulting in the construction of three sigma bonds and three stereocenters was realized in good yield.     

Synthesis of flavonoid analogues as scaffolds for natural product-based combinatorial libraries

The design and synthesis of flavonoid analogues as combinatorial scaffolds is reported. Using commercially available materials, we synthesized chalcones with fluoro and carboxy groups. Nitration of these compounds generated highly functionalized flavonoid scaffolds with an o-fluoronitrobenzene template. Subsequent cyclizations of these chalcones resulted in the formation of several flavone and flavonone scaffolds. One of the flavonones was chosen as the scaffold to synthesize flavonoid derivatives on the solid phase. A series of flavonoid derivatives were obtained in high yields, which demonstrates that these highly functionalized scaffolds can be used in the synthesis of natural product-based combinatorial libraries for drug discovery.     

Vertex operator algebras, extended diagram, and McKay's observation on the Monster simple group

We study McKay's observation on the Monster simple group, which relates the -involutions of the Monster simple group to the extended diagram, using the theory of vertex operator algebras (VOAs). We first consider the sublattices of the lattice obtained by removing one node from the extended diagram at each time. We then construct a certain coset (or commutant) subalgebra associated with in the lattice VOA . There are two natural conformal vectors of central charge in such that their inner product is exactly the value predicted by Conway (1985). The Griess algebra of coincides with the algebra described in his Table 3. There is a canonical automorphism of of order . Such an automorphism can be extended to the Leech lattice VOA , and it is in fact a product of two Miyamoto involutions. In the sequel (2005) to this article, the properties of will be discussed in detail. It is expected that if is actually contained in the Moonshine VOA , the product of two Miyamoto involutions is in the desired conjugacy class of the Monster simple group.

     

A new derivation of the vectorial equation of motion for a test particle in the Schwarzchild field

A new derivation of the vectorial equation of motion for a test particle in the Schwarzchild field is given which greatly simplifies the procedure given by C.A.Murray.     

DIRECT COMPACTIFICATION OF HETEROTIC STRINGS FROM 26 TO 4 DIMENSIONS VIA T22/G

We discuss compactificstion of the heterotic string in a U=T²²/G manifold, where G acts on the 22-dimensional torus T²² without fixed points. This non-trivial mixture of the internal 16-dimensional space enables chiral theories to exist in U. In a11 the three examples which we discuss in detail,the symmetry groups after compactification are all equal to E₆×SU(3)×E₈', though the imbeddings of these groups in E₆×E₈' are different for different cases. The resulting numbers of massless chiral fermion multiplets are a1so different.     

THIRD STRUCTURE FUNCTION IN TWO PHOTON PROCESSES AND GLUON PROPERTIES

We show how the structure function W, for two photon scattering is related to gluon spin strongly. We also Show that due to triple gluon coupling W, can be calculated to o(g²) in perturbative QCD.     

Introduction of a New Devices for Sampling Organic Pollutants

A new mimic biological sampling devices, which consisted of lipid-containing semipermeable-membrane (SPMD) for sampling organic pollutants has been introduced.     

Heat transfer for diode side-pumped YAG slabs

Thermal heating is a major limiting factor in scaling the average power of a solid-state laser. The heat transfer coefficient is affected by the coolant flow rate, the physical properties of the laser slab and the coolant, and the pumping cavity geometry. The relationship between the heating effects and the heat transfer coefficient has been studied by considering the variations of thermal conductivity and expansion coefficient of the laser slab with temperature. It is concluded that different heat transfer coefficients should be adopted according to different heat intensities inside the laser slabs in order to obtain better pumping input as well as to optimize the cooling effects.     

Understanding and controlling laser intensity noise

We present unified theoretical expressions for laser intensity noise in the presence of injection locking and feedback. We discuss optimum control strategies for different configurations and frequency regions. We illustrate the various effects with experimental results from Nd : YAG non-planar ring oscillator lasers.