Isolation and Structure Elucidation of Nortriterpenoids from Schisandra rubriflora

Seven new highly oxygenated nortriterpenoids, rubriflorins D–J ( 1 – 7 ), were isolated from the leaves and stems of Schisandra rubriflora, and their structures were elucidated on the basis of extensive analysis of spectroscopic data. These new compounds feature the opening of ring A compared with related known nortriterpenoids isolated from the genus Schisandra and showed weak activity against HIV‐1.     

吹气孔直径对RH精炼过程钢液流动和混合特性的影响

针对90t RH精炼装置,以水力学模拟研究了吹气孔直径对真空循环精炼过程中钢液流动和混合特性的影响.模型和原型的相似比为15.模型吹气孔直径分别为0.8 mm和1.2 mm.结果表明,1.2 mm孔径下环流量和主要工艺参数间的关系为Ql Q80.26Du0.69Dd0.80;在给定的吹气量和插入管内径下,增大吹气孔直径并不显著改变精炼过程中钢液流动特征,环流量随吹气孔直径的增大而略有增大,其关系式为Ql=2.40Q 0.23gD0.72u D0.88d d0.13in;相应地,混合时间稍有缩短;0.8和1.2 mm孔径下,τm与搅拌能密度的关系分别为τm ε5和τm ε0.49.     

Chemical Speciation of Amphoteric Ions on Semi‐Dry Scrubber Residue and Bag‐House Ash from MSWI

Two series of size‐fractionated combusted residues, a bag‐house ash and a scrubber residue, from a municipal solid waste incinerator (MSWI) were prepared and extracted by means of sequential chemical extraction (SCE) procedures proposed by Tessier. Concentrations of water‐soluble phase, exchangeable phase, carbonated phase, Fe/Mn oxide phase, organic matter phase, and residual phase bound amphoteric metals (Pb and Zn) were obtained, and have been compared with those of single batch extraction of toxic characteristic leaching procedure (TCLP). In each size fraction of baghouse ash or scrubber residue, lead or zinc shows a common phenomena that the TCLP value is always lower than the content of the water‐soluble fraction. For lead, baghouse ash has a significant size‐dependent distribution on the water‐soluble phase to perform a size‐dependent test of lead in the TCLP test. The zinc TCLP data having less size dependence might be due to that neither the baghouse ash nor the scrubber residue has a size‐dependent distribution on the water‐soluble zinc phase.     

投资组合保险CPPI策略研究

随着期权理论应用的发展,投资组合保险在国外已成为一种盛行的资产配置策略, 常数比例投资组合保险策略(CPPI)以其模型简单、参数的设置又能充分反映投资人不同的风险偏好、而且易于实施,成为大型安全型基金的基金经理首选的投资策略.本文研究并推广了CPPI策略,找出CPPI与期权的关系,讨论了借贷限制对(CPPI策略的影响,最后对CPPI策略在中国市场的可投资性进行了评测.     

Determination of the orientation of the electric field gradient at the Cu(1) site from the Mössbauer spectra of textured pellets made of YBa2Cu3O7−δ superconductor

A textured pellet of YBa₂Cu₃O_7?δ was prepared and doped with⁵⁷Co. After subsequent heat treatments the cobalt was found at the two copper sites. The degree of alignment of individual crystallites (about 40%) was determined from the Mössbauer spectrum by using a method developed by the authors [1]. The same method showed that the most characteristic doublet component of such spectra (δ=0.08 mm/s; |ΔE _Q|=1.96 mm/s) is associated with a site, most probably a Cu(1) site, where the EFG is parallel to thec direction of the unit cell. The sign ofV _zz turned out to be negative, giving a negative quadrupole splitting (ΔE _Q=?1.96 mm/s) for that component.     

同步辐射与GGG：Nd^3＋晶体的相互作用

用北京同步辐射489A-VUV束线作为连续光源测定了GGG:Nd~(3+)晶体的短波吸收光谱。用束线4B9A-WX作为光源激发GGG:Nd~(3+),测定了它的XEOL(X-ray excited optical luminescence)。     

Synthesis of 5‐Radioiodoarabinosyl Uridine Analog for Probing the HSV‐1 Thymidine Kinase Gene

Tumor cells transduced with herpes simplex virus thymidine kinase gene have been intensively applied to the field of positron emission tomography via imaging of its substrate. As a pilot synthesis approach, a facile preparation of 5‐[¹²⁵I] iodoarabinosyl uridine starting from commercially available uridine is reported herein.     

Frame Wavelets with Compact Supports for L^2（R^n）

The construction of frame wavelets with compact supports is a meaningful problem in wavelet analysis. In particular, it is a hard work to construct the frame wavelets with explicit analytic forms. For a given n × n real expansive matrix A, the frame-sets with respect to A are a family of sets in R^n. Based on the frame-sets, a class of high-dimensional frame wavelets with analytic forms are constructed, which can be non-bandlimited, or even compactly supported. As an application, the construction is illustrated by several examples, in which some new frame wavelets with compact supports are constructed. Moreover, since the main result of this paper is about general dilation matrices, in the examples we present a family of frame wavelets associated with some non-integer dilation matrices that is meaningful in computational geometry.     

Image Displaying Method of Ground-Based Millimeter Wave Radiometric Imaging System

The image displaying methods used in a millimeter wave radiometric imaging system have great influence on its imaging quality. In order to obtain high quality millimeter wave radiometric images, intensive studies on the image displaying methods are needed. This paper describes the image displaying method of Ground-based 8mm Millimeter Wave Radiometric Imaging (GMWRI) system and compares two different image displaying methods. The experimental results prove the unequal size element arc displaying method fits GMWRI system better.     

Synthesis of grafted poly(p‐phenyleneethynylene) with energy donor–acceptor architecture via atom transfer radical polymerization: Towards nonaggregating and hole‐facilitating light‐emitting material

In this contribution, we demonstrate a new effective methodology for constructing highly efficient and durable poly(p‐phenyleneethynylene) (PPE) containing emissive material with nonaggregating and hole‐facilitating properties through the introduction of hole‐transporting blocks into the PPE system as the grafting coils as well as building the energy donor–acceptor architecture between the grafting coils and the PPE backbone. Poly(2‐(carbazol‐9‐yl)ethyl methacrylate) (PCzEMA), herein, is chosen as the hole‐transporting blocks, and incorporated into the PPE system as the grafting coils via atom transfer radical polymerization. The chemical structure of the resultant copolymer, PPE‐g‐PCzEMA, was characterized by NMR and gel permeation chromatography, showing that the desirable copolymer was obtained with the narrow polydispersity. The increased thermal stability of PPE‐g‐PCzEMA was confirmed by thermogravimetric analysis and differential scanning calorimetry along with its macroinitiator. The optoelectronic properties of this copolymer were studied in detail by ultraviolet‐visible absorption, photoluminescence emission and excitation spectra, and cyclic voltammogram (CV). The results indicate that PPE‐g‐PCzEMA exhibits the solid‐state luminescent property dominated by individual lumophores, and also the energy transfer process from the PCzEMA blocks to the PPE backbone with a relatively higher energy transfer efficiency in the solid‐state compared to that of the solution state. Additionally, the hole‐injection property is greatly facilitated due to the presence of PCzEMA, as confirmed by CV profiles. All these data indicate that PPE‐g‐PCzEMA is a good candidate for use in optoelectronic devices. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3776–3787, 2007