Lie Bialgebras of Generalized Virasoro-like Type

In this paper, Lie bialgebra structures on generalized Virasoro-like algebras are studied. It is proved that all such Lie bialgebras are triangular coboundary.     

Mean First-Passage Time in a Bistable Kinetic Model with Stochastic Potentials

The transient properties of a bistable system with the stochastic potentials are investigated. The explicit expressions of the mean first-passage time (MFPT) are obtained by using a steepest-descent approximation. The results show that the MFPT of the system increases with the amplitude Δ of the stochastic potential, decreases with the noise intensity D and the correlation length l. The stochastic potential makes against the particle moving towards the destination.     

广义Kawahara方程的Cauchy问题

对初值在Besov空间中的广义Kawahara方程(э)tu+αuk(э)xu+β(э)3xu+γ(э)5xu=0进行了研究,其中k是大于4的正整数,证明了对任意的1≤q≤∞,其Cauchy问题在Besov空间Bsk2,q(R)和Bs2,q(R)中局部适定,这里sk=k-8/2k,s＞max(0,sk);对小初值问题几乎整体适定.并证明了如果β=0或βγ＜0,对小初值问题整体适定.     

Novel 2‐Arylbenzofuran Derivatives from Artocarpus petelotii

Further phytochemical investigations on the root barks of Artocarpus petelotii Gagnep afforded four novel isoprenylated 2‐arylbenzofuran derivatives, namely artopetelins D–G ( 1 – 4 ). Their structures were elucidated by spectroscopic methods, mainly by 2D‐NMR techniques. The biogenetic origins of artopetelins F and G ( 3 and 4 ) were also postulated.     

A New Triterpenoid Saponin from the Seeds of Deccaria segetalis

The seeds of Vaccaria segetalis (Neck) Garcke, which is distributed all over China,except southern China, are used in Chinese folk medicine for promoting diuresis,activating blood circulation and relieving carbuncles 1. Previous studies on the seeds ofthis plant have led to the isolation of seven cyclic peptides 2-5 and several saponins 6-]o.We have repoyted the isolation and structural elucidation of Segetosides A, C-E from theseeds of Vaccaria segetalis I I-13. FuFther investigation of…     

Al and Ti secondary neutral and secondary ion emission from oxide samples in the high-frequency sputtering mode of HF-plasma SNMS

A strong Al⁺ and a minor Ti⁺ peak without a proportional increase of the O⁺ signal in SNMS high-frequency sputtering mode (HFM) time profiles of an insulating μm-thick oxide layer on Ti-48Al-2Cr-2Nb led us to check for a possible contribution of positive secondary ions (SI⁺). SI⁺ and SI^– (negative secondary ions) can be detected in ion energy spectra. This is shown using Al⁺, O^–, AlO^–, and AlO₂ ^– ions sputtered from massive Al₂O₃. Similarly, and depending on stoichiometry, also Ti⁺ from mixed sintered, microscopically inhomogeneous Al₂O₃-TiO₂-SiO₂ pellets has been identified to be partly SI⁺. The subtraction of an assumed contribution of ionized secondary neutrals (SN⁺) suggests that SI⁺ may form several 10% of the detected ions obtained in the HFM sputtering and plasma processes. However, the positive surface potential of some 10 V being necessary to cause detectable SI⁺ contributions does not build up on μm-thin insulating layers. Therefore, we have to conclude that the Al⁺ and Ti⁺ peaks in the sputter time profiles of the μm-thick oxide layer on Ti-48Al-2Cr-2Nb which are accompanied by an O⁺ deficiency cannot have been caused by SI⁺. Instead, their more probable origin is the inhomogeneous Al₂O₃ interlayer itself. Together with the residues of a topmost TiO₂ layer which has strongly been depleted in O by preferential sputtering, the relative O⁺ deficiency may be explained without assuming SI⁺ contributions. Received: 22 February 1999 / Revised: 1 July 1999 / Accepted: 6 July 1999     

Connection Among Some Optimal Criteria for Symmetrical Fractional Factorial Designs

A fundamental and practical question for fractional factorial designs is the issue of optimal factor assignment. Recently, some new criteria, such as generalized minimum aberration, WV-criterion, NB-criterion and uniformity criterion are proposed for comparing and selecting fractions. In this paper, we indicate that these criteria agree quite well for symmetrical fraction factorial designs.     

Mechanism of cleaving DNA through hydrolysis of a novel complex of Mg containing dien ligand

A series of elements necessary for life bodies, such as Mg, Cu, Mn, Fe, Co, Zn etc, arechosen as ceflter ions of complexes, because most of them act as active centers ofenZymes and auxiliary factors. We select dien as ligand because nitrogen, especiallymuti-nitrogen coordination is general in natural enzymes and simulated systems,furthermore dien has structural flexibility.The complexes of Mg containing dien and the activity of cleaving DNAA series of metals, such as Mg, Mn, Fe, Co, Ni, …     

Circular neighbor-balanced designs universally optimal for total effects

In many experiments, the performance of a subject may be affected by some previous treatments applied to it apart from the current treatment. This motivates the studies of the residual effects of the treatments in a block design. This paper shows that a circular block design neighbor-balanced at distances up toγ≤k - 1, where k is the block size, is universally optimal for total effects under the linear models containing the neighbor effects at distances up toγamong the class of all circular binary block designs. Some combinatorial approaches to constructing these circular block designs neighbor-balanced at distances up to k - 1 are provided.