线性模型下F-检验最优的误差协方差结构

文献中回归参数线性假设的F-检验统计量主要包括基于广义最小二乘估计F- 统计量F(θ),基于最小二乘估计的F-统计量FLSE以及Wu C．F．J．等于1988年提出的调整的F-统计量FA(θ)．其中后两者因形式简单而常常被广泛采用．本文主要研究了FA(θ)和FLSE的最优性,并分别获得了FA(θ)=F(θ)和ELSE=F(θ)的充要条件．最后,我们将所得的结果应用到医药领域的两类重要模型．     

Monitoring the Hydrolysis of Olive Oil Catalyzed by Lipase via Acid Value Detection

IntroductionThe lipase-catalyzed hydrolysis of oils is widelyused for the preparation of glycerides and fatty acidsbecause of the substrate specificity of lipase[1—3]. Thereaction is carried out under mild conditions.Candidalipolyticalipase is a nonspeci…     

Silane grafting and crosslinking of ethylene-octene copolymer

Vinyl trimethoxysilane (VTMS) and vinyl triethoxysilane (VTES) grafted ethylene-octene copolymer (POE) were prepared in the melt process. The effects of silane concentration, reaction time and temperature on the silane grafting were investigated, and the grafting reaction was in situ monitored using the differential scanning calorimetry (DSC). The silane grafted POE was characterized by the Fourier transform infrared spectroscopy (FTIR) and melt flow index (MFI). MFI data of the silane grafted POE show that the MFI value is affected not only by DCP concentration, but also by silane concentration. The difference of gel content between VTMS and VTES crosslinked POE indicates that for POE, the grafting reaction activity of VTES is higher than that of VTMS. Moreover, the thermal behavior and mechanical properties of the crosslinked POE were also studied. It has been found that the thermal stability and mechanical properties of the silane crosslinked POE are greatly improved.     

Synthesis and characterization of a main‐chain‐type conjugated copolymer containing rare earth with photocrosslinkable group

In this article, we report the design, synthesis, and characterization of a new main‐chain‐type rare earth‐containing conjugated polymer with photocrosslinkable group. The polymer is crosslinked photochemically by the addition of a photoinitiator to yield an absolute insoluble network. The optical properties of the resulting conjugated polymer were characterized in solution, film state, and after photocrosslinking. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 388–394, 2007.     

An Efficient Synthesis of Cyclopeptides Bridged with Aliphatic-aryl Ether Bond

Based on the pseudo-dilution effect (PDE) on solid support, three cyclopeptides with an aliphatic-aryl ether bond as the bridge were synthesized via SN2 reaction between bromoacetylated at N-terminal and the phenol -OH group in C-terminal Tyr residue. All the products were obtained in good overall yields and characterized by related analytic data.     

On the Edge-forwarding Indices of Frobenius Graphs

A G-Frobenius graph F, as defined by Fang, Li, and Praeger, is a connected orbital graph of a Frobenius group G = K × H with Frobenius kernel K and Frobenius complement H. F is also shown to be a Cayley graph, F = Cay（K, S） for K and some subset S of the group K. On the other hand, a network N with a routing function R, written as （N, R）, is an undirected graph N together with a routing R which consists of a collection of simple paths connecting every pair of vertices in the graph. The edge-forwarding index π（N） of a network （N, R）, defined by Heydemann, Meyer, and Sotteau, is a parameter to describe tile maximum load of edges of N. In this paper, we study the edge-forwarding indices of Frobenius graphs. In particular, we obtain the edge-forwarding index of a G-Frobenius graph F with rank（G） ≤ 50.     

A Taxatetraene from Microbial Transformation of Sinenxan A

Sinenxan A [2α, 5α, 10β, 14β-tetraacetoxytaxa-4(20), ll-diene, 1] was biotransformed by a filamentous fungus, Aspergillus niger JCM 5546, and an unusual taxatetraene [2α,5α-acetoxytaxa-4(20), 10(11), 12(18), 13(14)-tetraene, 2], together with two known products,10β-deacetyl sinenxan A (3) and 10β, 14β-dideacetyl sinenxan A (4) were produced.     

Microwave promoted one-pot synthesis of 3-(2''-amino-3''-cyano-4''-arylpyrid-6''-yl) coumarins

A facile procedure for the synthesis of 3-(2'-amino-3'-cyano-4'-arylpyrid-6'-yl) coumarins are being reported starting from 3-acetylcoumarin, aromatic aldehydes and malononitrile. The reactions were carded out on microwave irradiation in good yield with short time and easy work-up. The structures of all the compounds have been confirmed on the basis of their analytical, IR,1H NMR,and mass spectral data.     

Preparation and properties of well‐defined waterborne polyurethaneurea with fluorinated siloxane units in hard or soft segments

Two series of well‐defined polyurethaneurea (PUU) aqueous dispersions consisting of fluorinated siloxane units in the hard and the soft segments, respectively, were prepared from polyester polyol, α,ω‐dihydroxypoly[(3,3,3‐trifluoropropyl) methylsiloxane] (PTFPMS), dimethylolpropionic acid, isophorone diisocyanate, and ethylenediamine. These anionic aqueous dispersions were stable at the ambient temperature for more than 6 months. The experimental results showed that the water‐resistance performance of the PUU films prepared with the insertion of PTFPMS units into the hard segments (HFS series) were better than those prepared with the insertion of PTFPMS units into the soft segments (SFS series). The film prepared from the PUU aqueous dispersion incorporating 5 wt % PTFPMS in the hard segments exhibited the lowest water absorption amount (2.3 wt %) with the contact angle of water on the film surface greater than 90°. In comparison with the PUU film without adding PTFPMS, the waterproof performance and the mechanical properties of both HFS and SFS series were enhanced markedly. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5005–5016, 2007