Synthesis of bis(amine anhydride)s for novel high T(g)s and organosoluble poly(amine imide)s by palladium-catalyzed amination of 4-chlorophthalide anhydride

Two novel bis(amine anhydride)s, NN-bis(3,4-dicarboxyphenyl)aniline dianhydride (I) and N,N-bis(3,4-dicarboxyphenyl)-p-tert-butylaniline (II), were synthesized from the palladium-catalyzed amination reaction of N-methyl-protected 4-chlorophthalic anhydride with arylamines, followed by alkaline hydrolysis of the intermediate bis(amine-phthalimide)s and subsequent dehydration of the resulting tetraacids. The X-ray structures of anhydride I and II were determined. The obtained dianhydride monomers were reacted with various aromatic diamines to produce a series of novel polyimides. Because of the incorporation of bulky, propeller-shaped triphenylamine units along the polymer backbone, all polyimides exhibited good solubility in many aprotic solvents while maintaining their high thermal properties. These polymers had glass transition temperatures in the range of 298-408 degrees C. Thermogravimetric analysis showed that all polymers were stable, with 10% weight loss recorded above 525 degrees C in nitrogen.The tough polymer films, obtained by casting from solution, had tensile strength, elongation at break, and tensile modulus values in the range of 95-164 MPa, 8.8-15.7%, and 1.3-2.2 GPa, respectively.

Assembly of multilayer films containing iron(III)- substituted Dawson-type heteropolyanions and its electrocatalytic properties: cyclic voltammetry, electrochemical impedance spectroscopy and UV-Vis spectrometry

Ultrathin multilayer films have been prepared by means of alternate adsorption of iron(Ill)-substituted heteropolytungstate anions and a cationic redox polymer on the 4-aminobenzoic acid modified glassy carbon electrode surface based on electrostatic layer-by-layer assembly. Cyclic voltammetry, electrochemical impedance spectroscopy and UV-Vis absorption spectrometry have been used to easily monitor the uniformity of thus-formed multilayer films. Especially, the electrochemical impedance spectroscopy is successfully used to monitor the multilayer deposition processes and is a very useful technique in the characterization of multilayer films because it provides valuable information about the interfacial impedance features. All these results reveal regular film growth with each layer adsorption. The resulting multilayer films can effectively catalyze the reduction of H2O2,NO2- and BrO3-.

Synthesis of tetra-iron substituted sandwich-type pentadecatungstodiarsenate and its multilayers on glassy carbon electrode by self-assembly with electrocatalytic properties

A novel sandwich-type compound, Na-12 [Fe-4 (H2O)(2) (As2W15O56)(2)] . 38H(2)O (denoted as Fe(4)AS(4)W(30)) was synthesized. The compound was well characterized by means of IR, UV-Vis, W-138 NMR and elemental analyses. Redox electrochemistry of the compound has been studied in acid buffer solutions using cyclic voltammetry(CV). The compound containing multilayer films has been fabricated on the 4-aminobenzoic acid(4-ABA) modified glassy carbon electrode(GCE) surface by alternate deposition with a quaternized poly (4-vinylpyridine) partially completed with [Os(bpy)(2)Cl](2+/-) (denoted as QPVP-Os). CV, X-ray photoelectron spectroscopy (XPS) and UV-Vis spectroscopy were used to characterize the asprepared multilayer films. It is proved that the multilayer films are uniform and stable. The electrocatalytic activities of the multilayer films were investigated on the reduction of two substrates of important analytical interest, NO2- and H2O2.

Isochiral form II of syndiotactic polypropylene produced by epitaxial crystallization

Epitaxial crystallization of syndiotactic polypropylene (sPP) on 2-quinoxalinol (2-Quin) yields, in the lower part of the crystallization range, the less common and metastable form II based on the packing of isochiral helices, rather than the stable antichiral form I. The contact plane is (110)(II). Form II exits only as a thin layer (< 50 nm) near the substrate surface. During further growth away from the surface, a transition takes place to the disordered form I, observed in "conventional" thin film growth. The epitaxial relationship rests only partly on dimensional matching with the chain axis repeat distance (which would be valid for both forms I and II) and on interchain distances. Whereas a better dimensional match would be achieved with form I, selection of the isochiral form II results from better correspondence of the surface topographies of the deposit (110)(II) sPP and substrate 2-Quin (001) contact faces.

Crystal structure and its transition for poly(aryl ether ketone ketone)s .1.

Poly(aryl ether ketone ketone)s (PEKK) was a high-performance engineering plastics, By means of Wide Angle X-ray Diffraction (WAXD) and Differential Scanning Calorimetry (DSC) methods, PEKK samples crystallized in solvent induction, from glass state and from melting state were studied, Crystal forms I and II for PEKK were found, The formation of crystal form II was dependent on thermal history and solvent induction, and this form II had melting point 10 degrees C or so lower than that of form I crystallized from glass state, All PEKK samples had low melting peaks which were relevant to the polarization of PEKK molecular chain, while they had nothing to do with thermal history, The heat of fusion for PEKK low melting peaks accounted for,percentage of 2 to 10 or so of the whole heat of fusion, And PEKK has its equilibrium melting point of 409 degrees C.

Control mechanisms of diel vertical migration: Theoretical assumptions

We explore control mechanisms underlying the vertical migration of zooplankton in the water column under the predator-avoidance hypothesis. Two groups of assumptions in which the organisms are assumed to migrate vertically in order to minimize realized or effective predation pressure (type-I) and to minimize changes in realized or effective predation pressure (type-II), respectively, are investigated. Realized predation pressure is defined as the product of light intensity and relative predation abundance and the part of realized predation pressure that really affects organisms is termed as effective predation pressure. Although both types of assumptions can lead to the migration of zooplankton to avoid the mortality from predators, only the mechanisms based on type-II assumptions permit zooplankton to undergo a normal diel vertical migration (morning descent and evening ascent). The assumption of minimizing changes in realized predation pressure is based on consideration of DVM induction only by light intensity and predators. The assumption of minimizing changes in effective predation pressure takes into account, apart from light and predators also the effects of food and temperature. The latter assumption results in the same expression of migration velocity as the former one when both food and temperature are constant over water depth. A significant characteristic of the two type-II assumptions is that the relative change in light intensity plays a primary role in determining the migration velocity. The photoresponse is modified by other environmental variables: predation pressure, food and temperature. Both light and predation pressure are necessary for organisms to undertake DVM. We analyse the effect of each single variable. The modification of the phototaxis of migratory organisms depends on the vertical distribution of these variables. (C) 2001 Academic Press.

大型铰接并联六维测力平台摩擦建模

在已有制造工艺及标定技术基础上,为进一步改善大型铰接并联六维测力平台的测量精度,本文基于螺旋理论和影响系数原理,引入符号函数建立了Stewart结构大型铰接六维测力平台的摩擦模型。文中提出了关节摩擦对铰接并联六维测力平台测量精度的影响矩阵及I、H类误差表达式,绘制了在不同外载和关节摩擦系数条件下,六维测力平台的I、II类误差曲线,并总结丁关节摩擦和平台自重对测力平台测量精度的影响规律。为具有普通球形铰链人型Stewart平台六维测力下台精度的提高和改善提供了理论基础。

子洲—清涧地区上古生界储层综合研究

The exploration and study in recent years shows that the upper Paleozoic in the east of Ordos Basin possesses major exploration potential, so it is necessary to have a comprehensive and synthetic research in this area. Following the guideline of T.A. Cross’s high resolution sequences stratigraphy and combined with sedimentology, the strata and sequence in the research area are divided and correlated. This paper emphasizes on the reservoir in this area and its major fruits are: Firstly, form the framework of the high sequence stratigraphy through mainly studying on the data of core, well drilling and field section combining. Then, think that the best reservoir formation mainly appears in the middle or lower part of long arising semi-cycle, and focus on A type and C1 middle sequence cycle that contributes to the development of formation. Next, think the sedimentary source mainly comes from the epimetamorphic crystalline basement in the north of the Ordoes Basin through analyzing depositional background, researching on sandstone petrography, distribution characteristics of the sedimentary system as well as researching on heavy mineral combination characteristics. Fourthly, give priority to Zizhou-Qingjian area for the first time and gain seven lithofacies paleography maps in the No.2 member of Shanxi and the No.8 member of Shihezi through using the method of isochronal lithofacies paleogeography mapping, then bring forth that Sh2 is mainly developed a type I sequence under the margin of ramp lake-basin background. Fifthly, through researching on the characteristics of reservoir petrography and diagenesis, think that all researched areas experienced compaction and cementation, and there is different types of rocks, only little of the primary pores that are made up of litharenite and lithoclastic quartz sandstone is left, while in lithoclastic quartz sandstone, there are still many primary pores Sixthly, through studying on pore types, microstructure, as well as physical property on the key formation, think that the researched area mostly appears typical low pore, low porosity and permeability, which mainly result from sedimentary and diagenesis. Lastly, through researching on classified evaluation in the key formation, productivity analysis, and combing with reservoir distribution, the researched area is divided into three parts, and think that exploration should be emphasized on formation I and II. The characteristics of sandstones distribution in Sh23 member, gas formation distribution and open flow capacity of exploitation well are all consistent properly with the results of reservoir comprehensive evaluation in this thesis proved by the gas production development in 2006.

Relations between A-type granites and copper mineralization as exemplified by the Machangqing Cu deposit

This paper deals with the relations between the Machangqing rockbody which corresponds to the A-type granites and porphyry copper mineralization in terms of petrochemistry, trace element geochemistry, fluid inclusion geochemistry and isotope geochemistry. The results show that the Machangqing porphyry copper deposit was formed from the fluid predominated by mag-matic fluid. This kind of ore-forming fluid was just differentiated from the magma responsible for the A-type granites. therefore,as viewed from whereer they contain water or not,the A-type granites can,at least,be divided into two types: water-bearing and water-free.The water-bearing A-type granites can serve as the host ofporphyry copper deposits under certain geological conditions.