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301.
Dong Y Lam JW Qin A Li Z Sun J Sung HH Williams ID Tang BZ 《Chemical communications (Cambridge, England)》2007,(1):40-42
(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. 相似文献
302.
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. 相似文献
303.
Synthesis of flavonoid analogues as scaffolds for natural product-based combinatorial libraries 总被引:2,自引:0,他引:2
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. 相似文献
304.
Ching Hung Lam Hiromichi Yamada Hiroshi Yamauchi 《Transactions of the American Mathematical Society》2007,359(9):4107-4123
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.
305.
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. 相似文献
306.
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. 相似文献
307.
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. 相似文献
308.
ZHANG Yong HONG Hua-Sheng Michael H W Lam Ka-Fai Poon Bruce J Richardson Rudolf S S Wu Gene J S Zheng 《高等学校化学学报》1999,20(Z1):554
A new mimic biological sampling devices, which consisted of lipid-containing semipermeable-membrane (SPMD) for sampling organic pollutants has been introduced. 相似文献
309.
Heat transfer for diode side-pumped YAG slabs 总被引:1,自引:0,他引:1
Wenjie Xie Siu. -Chung Tam Hongru Yang Jianhui Gu Gang Zhao Yee-Loy Lam Wilson Tan 《Optics & Laser Technology》1999,31(7):521
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. 相似文献
310.
Ralph T. C. Huntington E. H. Harb C. C. Buchler B. C. Lam P. K. Mcclelland D. E. Bachor H.-A. 《Optical and Quantum Electronics》1999,31(5-7):583-598
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. 相似文献