Two New Eremophilenolides from Ligularia muliensis

Many Ligularia species have long been used as traditional folk medicine for theirantibiotic, antiphlogistic and antitussive activities1, and were found to be an importantsource of eremophilane. In the course of our search for bioactive sesquiterpenoids, w…     

Weak-mixing implies sensitive dependence

Let X be a metric space, B the σ-algebra of Borel subsets of X, and μ a probability measure on (X,B). In this note, for a measure-preserving map T (respectively a measure-preserving semi-flow φ) on (X,B,μ), we prove that if suppμ=X, and T (respectively φ) is weak-mixing, then T (respectively φ) has sensitive dependence.     

An approximate proximal-extragradient type method for monotone variational inequalities

Proximal point algorithms (PPA) are attractive methods for monotone variational inequalities. The approximate versions of PPA are more applicable in practice. A modified approximate proximal point algorithm (APPA) presented by Solodov and Svaiter [Math. Programming, Ser. B 88 (2000) 371–389] relaxes the inexactness criterion significantly. This paper presents an extended version of Solodov–Svaiter's APPA. Building the direction from current iterate to the new iterate obtained by Solodov–Svaiter's APPA, the proposed method improves the profit at each iteration by choosing the optimal step length along this direction. In addition, the inexactness restriction is relaxed further. Numerical example indicates the improvement of the proposed method.     

Existence of two solutions of m-point boundary value problem for second order dynamic equations on time scales

In this paper, by means of a new twin fixed-point theorem in a cone, the existence of at least two positive solutions of m-point boundary value problem for second order dynamic equations on time scales is considered.     

p型导电掺In的SnO_2薄膜的制备及表征

采用溶胶 凝胶提拉法成功地制备了p型导电掺In的SnO2 薄膜 .x射线衍射测试结果表明 ,掺In的SnO2 薄膜保持SnO2 的金红石结构 .吸收谱测试结果表明 ,掺In的SnO2 禁带宽度为 3 8eV .霍尔测量结果表明 ,空穴浓度与热处理温度有很大的关系 ,5 2 5℃为最佳热处理的温度 .铟锡原子比在 0 0 5— 0 2 0范围内 ,空穴的浓度与In的含量有直接的关系 ,并随In含量的增加而增加     

海洋激光雷达测量海中悬移质

研制了一套采用倍频YAG激光器的小型海洋激光雷达，用于测量海中悬移质浓度，2000年8月28日至9月5日，该系统安装于“东方红Ⅱ”号右舷下甲板，在渤海海区进行海中悬移质浓度现场测量，通过对18个站位的海洋激光雷达数据分析，获得的表层悬移质浓度与同步测量的海中悬移质浓度结果吻合较好。     

Study on deactivation and regeneration of Pd/Al2O3 catalyst in hydrogen peroxide production by the anthraquinone process

Deactivated palladium catalysts in the hydrogenation of anthraquinione were regenerated with ethanol, nitric acid, hydrogen peroxide, boiling water and steam, respectively. The deactivated and regenerated catalysts were characterized by XPS, ICP, TG, FTIR, TPD, XRD, etc., and studied in the hydrogenation of anthraquinone. The results showed that the main cause of catalyst deactivation is the coverage of the active component by deposits. The treatments by hydrogen peroxide and boiling water can effectively regenerate the deactivated catalysts. This revised version was published online in August 2006 with corrections to the Cover Date.     

Bandwidth‐guaranteed QoS routing of multiple parallel paths in CDMA/TDMA ad hoc wireless networks

This paper investigates the issues of QoS routing in CDMA/TDMA ad hoc networks. Since the available bandwidth is very limited in ad hoc networks, a QoS request between two nodes will be blocked if there does not exist a path that can meet the QoS requirements, even though there is enough free bandwidth in the whole system. In this paper, we propose a new scheme of using multiple paths between two nodes as the route for a QoS call. The aggregate bandwidth of the multiple paths can meet the bandwidth requirement of the call and the delays of these paths are within the required bound of the call. We also propose three strategies by which to choose a set of paths as the route, namely, shortest path first (SPF), largest bandwidth first (LBF), and largest hop‐bandwidth first (LHBF). Extensive simulations have been conducted to evaluate the performance of the three strategies in comparison with a traditional single path routing algorithm. The simulation results show that the proposed multiple paths routing scheme significantly reduces the system blocking rates in various network environments, especially when the network load is heavy. Copyright © 2005 John Wiley & Sons, Ltd.     

The Exact Hausdorff Measure Function of the Level Sets of Multi-parameter Symmetric Stable Process

In this paper, we investigate the Hausdorff measure for level sets of N-parameter Rd-valued stable processes, and develop a means of seeking the exact Hausdorff measure function for level sets of N-parameter Rd-valued stable processes. We show that the exact Hausdorff measure function of level sets of N-parameter Rd-valued symmetric stable processes of index α is Ф（r） = r^N-d/α （log log l/r）d/α when Nα 〉 d. In addition, we obtain a sharp lower bound for the Hausdorff measure of level sets of general （N, d, α） strictly stable processes.     

离子束合成钇硅化物的结构及红外谱特征

将稀土金属钇离子注入到n型单晶Si(111)中制备出钇硅化物埋层.利用x射线衍射、卢瑟福背散射和傅里叶红外吸收谱测量分析了样品的结构、原子的埋层分布和振动模式.结果表明，Y离子在注入过程中已与基底中的Si原子形成了YSi2结构相.真空下的红外光辐照处理促使YSi2择优取向生长，埋层中Si与Y的平均原子浓度比由24下降为20，与六方YSi2的化学计量比一致.还给出了钇硅化物的特征红外吸收谱.