MECHANICAL MODEL FOR TWO-PHASE POLYMER BLEND SYSTEMS WITH THE CHARACTERISTICS OF PHASE INVERSION

For two-phase polymer blend systems, the phase inversion will take place as the blendcomposition is changed. In this paper a mechanical model has been proposed to describe themodulus-composition relation in the phase inversion region. The application of the mechanicalmodel to two polyurethane blend systems has been studied. It was found that the theoreticalprediction for the modulus-composition relation is quite consistent with the experimentalresults. Furthermore, the characteristics of the phase inversion can be determined uniquelyby the parameters involved in the mechanical model.     

THE PARAMETER KERNELS FOR THE LINEAR INVERSION OF THE FREE OSCILLATION OF THE EARTH (Ⅱ)

This is the second instalment of the paper, in which the method of derivation of the for-mulas of parameter kernels for the spheroidal oscillations are considered. The principle ofRayleigh is used to derive the formulas of the kernels of the two elastic parameters, i.e. μand λ. But for that of ρ, it is found very difficult to get satisfactory results. A new butsimpler approach is followed and very satisfactory results are obtained.     

PREPARATIVE AND STRUCTURAL STUDIES ON THE SUPERCONDUCTING PHASE YBa_2Cu_3O_(7-d)

Reasonably homogeneous samples were obtained by following the formula Y_(0.334)Ba_(0.666)CuO_(3-y) andusing citric acid as a complex-forming agent to improve the dispersion of the metal oxides. We havealso found that the variant condition in preparative procedure leads to variant deviation from tetrago-nality and that more pronounced deviation gives better superconducting properties. The crystal structure determined from X-ray powder diffraction diagrams confirms the stoichiom-etry of the metal ions and gives the positions of the oxygen atoms. The orthorhombic or pseudo-tetragonal unit cell with a=3.893, b= 3.813 and c= 11.687 A contains YBa_2Cu_3O_7. It is composed ofthree perovskite cubes with three copper atoms at their corners, the two barium atoms at the centers ofthe top and bottom cubes, and the yttrium at the center of the unit cell. The oxygen atoms sit on centersof cube edges. The positions (0 0 1/2) are vacant. The vacancies represented by (0(1/2)0) cause the ar-rangement of atoms to lose tetragonal symmetry, and have far-reaching effect for this phase. The yttriumand barium atoms are coordinated in a cuboctahedron respectively with four equatoria oxygen atoms at(0 0 1/2) and two at (0 1/2 0) removed. In the light of bond valence theory we can infer from the in-teratomic distances Y-O, Ba-O and Cu-O that the occupancy of the oxygen atoms at (1/2 0 0) is wellbelow unity while the positions (0 0 1/2) are vacant, the formula of the phase is YBa_2Cu_3O_(7-d), thefraction of Cu(Ⅱ) and (Ⅲ) for the set of copper at (0 0 0) is respectively d/0.5 and (1-d/0.5), and0.2相似文献   

STUDIES ON THE REACTION OF SULFUR,SELENIUM AND TELLURIUM WITH SODIUM HYDROXIDE UNDER PHASE TRANSFER CATALYSIS(Ⅱ).A CONVENIENT METHOD FOR THE SYNTHESIS OF BI(ACYL)DISULFIDES

A simple and general method for the synthesis of bi(acyl)disulfides isreported.Sulfur is allowed to react with sodium hydroxide to give sodium disulfideat 65℃ under PTC,which can react with acyl halides to afford bi(acyl)disulfides ingood to excellent isolated yields.The effects of solvents and phase transfercatalysts are discussed.     

STUDIES OK TRANSFORMATION FOR ZEOLITE CRYSTAL(Ⅲ)——THE STABILITY OF ZEOLITE NaY AND THE STRUCTURE OF ZEOLITE NaPc

We investigated the crystallization of NaY and especially the transformation for NaY to NaPc type zeolite from an initial gel of the batch composition 3.3Na2O Al2O3 10SiO2 200H2O at 100℃and the changes of zeolite structures in the process of the transformation crystal using the modern techniques,A more detailed liquid phase transportation mechanism of the transformation was suggested.     

THE SYNTHESIS AND CHARACTERIZATION OF THE COORDINATION COMPOUNDS OF Pt(Ⅱ)AND Ir(Ⅲ)WITH 2-MERCAPTOPYRIDINE-1-OXIDE AND ITS METHYL DERIVATIVES

Six coordination compounds of Pt(Ⅱ)L_2 and Ir(Ⅲ)L_3 type(where L is PT~-,3Me-PT~-or 4Me-PT~-)are reported here.Four coordination compounds of the lattertwo ligands have never been reported before,while PT~-'s were synthesized withH_2PtCl_6 and(NH_4)_3IrCl_6 respectively,which were different from the methods ofDavidson et al.~1 and Sterinbrech~2.They were characterized by elemental analysis,UV,IR,~1HNMR and molar conductance.Their structural formulas have beendetermined,and the mechanism of synthetic reaction has been discussed.     

STUDIES ON RESPONSE CHARACTERISTICS OF DRUG ION-SELECTIVE ELECTRODES (Ⅱ)——SULPHA-DRUG SENSITIVE ELECTRODES USING QUATERNARY PHOSPHONIUM AND ARSONIUM COMPOUNDS

Ion-pair complexes of sulphonamide derivatives with quaternary phosphonium and quaternary arsonium have been synthesized and their electrode performances studied. It has been found that the electrode functions depend mainly on the site cation rather than on the anionic species and deteriorate in the order of cetyhrioctylammonium>cetyltriphenylphosphonium> cetyhriphenylarsonium. The electrode selectivity for different sulpha-drugs decreases in the order of sulphathiazole>sulphamethoxazole>sulphadimethoxine, sulphadoxine>sulphacetamide>sulphadiazine>sulphanilamide. Selectivity coefficients depend not only on the molecular connectivity index χ, but also on the electronic charge at the ionizing amide nitrogen atom σ and pK, according to the following formula: logK_(ij)=aχ+bσ—CpK_a—d. The quaternary phosphonium type electrodes have been suggested for use in the potentiometric determinations of sulpha-drugs.     

ON THE POLYCONDENSATION REACTION WITH MONOMER OF A_aB_b TYPE (Ⅱ)——THE POLYMER MOMENTS

With monomer of A_aB_b type, the polymer moments of polycondensation reaction is inves-tigated in detail by means of direct differentiation technique to obtain a recursion formula.This formula is suitable for both pre-gel and post-gel in evaluating the polymer momentsexplicitly.     

REGULATION OF GLUCOCORTICOID RECEPTOR BY GLUCOCORTICOIDS(Ⅱ) ——THE STUDIES ON RAT LIVER, BRAIN AND SPLEEN

The concentration of glucocorticoids (GC) in plasma was maintained at stress level, 20--40μg/dl, for 3 days by subcutaneous injection of hydrocortisone (F) in polyvinyl alcohol (PVA) into rats, and the specific binding of [~3H]Dexamethasone (Dex) in liver, spleen and brain was determined before and after injection. The binding capacity of glucocorticoid receptor (GR) in liver and spleen was decreased significantly 1 h after injection and maintained at low level for several days after the concentration of GC in plasma had returned to the normal level. The K_d was not altered. The changes of GR in brain was not significant. Thus it may be concluded that GC can down-regulate GR in rats, but with different characteristics in various target organs.     

THE INTERACTION BETWEEN FORCED WAVE,FREE WAVE AND ZONAL FLOW(Ⅱ)——QU ALITATIVE ANALYSIS FOR THE TRANSITION AND oSCILLATION OF HIGH AND LOW INDEXES

In this second part, the so-called "discontinuous vibration analysing" method is used to discuss the qualitative features of the solutions in the system set up in Part I. The system and the phase space are divided into two subsystems and two subspaces, which are corresponding to the slow and fast varying processes respectively. The qualitative vector field and trajectories for solutions are analysed and the mechanisms for the transition and nonuniform oscillation of high and low indexes are discussed.     

STUDIES ON RESPONSE CHARACTERISTICS OF DRUG ISE''''S (Ⅲ)——ERYTHROMYCIN ELECTRODES AND THEIR SELECTIVITY TOWARD QUATERNARY AMMONIUMS

Erythromycin sensitive electrodes have been proposed. Their selectivity toward quaternary ammoniums is described in terms of induction effect and steric hindrance effect: logKil=a_1I-a_2Z/R+a_0, where I is induction effect index, a_1,a_2 and a_0 are coefficients which depend on the electro-active material. A general formula has been suggested to relate the electrode selectivity to the carbon atom number (n) of the alkyl of the quaternary ammonium; logK_(ij)=A/2.7~R-B/(0.80+1.26n)+C, where A, B and C are coefficients which depend on the electro-actlve material, logK_(ij) tends to a limited value C when n increases.     

THE GEOMETRY AND ORBITAL INTERACTION OF TRIATOMIC CLUSTERS FOR Cu,Ag,Au(Ⅱ)

ＴＨＥＧＥＯＭＥＴＲＹＡＮＤＯＲＢＩＴＡＬＩＮＴＥＲＡＣＴＩＯＮＯＦＴＲＩＡＴＯＭＩＣＣＬＵＳＴＥＲＳＦＯＲＣｕ，Ａｇ，Ａｕ（Ⅱ）￥ＨａｎＸｉｎｇＬＩＵ（ＡｄｖａｎｃｅｄＭａｔｅｒｉａｌｓＲｅｓｅａｒｃｈＩｎｓｔｉｔｕｔｅ，ＷｕｈａｎＵｎｉｖｅｒｓｉ...     

STUDIES OF THE CRYSTALLIZATION BEHAVIOR IN THE CRYSTALLINE/AMORPHOUS POLYMER BLENDS: POLY(ETHYLENE OXIDE)/POLY(METHYL METHACRYLATE) AND POLY(ETHYLENE OXIDE)/POLY(VINYL ACETATE)

The crystallization process of poly(ethylene oxide) (PEO)/poly(methyl methacrylate) (PMMA)and PEO/poly(vinyl acetate) (PVAc) blends has been characterized by Fourier Transform Infrared(FTIR) spectra in conjunction with Differential Scanning Calorimeter (DSC) measurements. Thecrystallinity of PEO varies consistently with PEO content in PEO/PVAc blends and the PEO/PMMAblends containing 50 wt% or less PMMA. For the PEO/PMMA blends containing 60 wt% ormore PMMA, the crystallinity of PEO decreases more than PEO content but develops with crystal-lization time. These results can be explained in terms of difference between the crystallization tem-perature (T_c) and glass transition temperature (T_g) of the blends as a function of content of amorphouscomponent.     

THE INTRAMOLECULAR AROMATIC-RING STACKING INTERACTION OF MIXED LIGAND PALLADIUM(Ⅱ)COMPLEXES Ⅲ.STUDIES ON THE Pd~(2+)-A-UTP~(4-)SYSTEMS BY HNMR

The intramolecular aromatic-ring stacking interaction of mixed-ligand complex Pd(A)(UTP)~(2-)in the system pd~(2+)-A-UTP~(4-)has been determinedby ~1HNMR,where A=1,10-phenanthroline(phen),2,2'-bipyridyl(bpy)and DL-tryptophan(trp~-);UTP~(4-)=uridine 5-triphosphate.The result indicates that itis the partial stacking between the uracil ring of UTP~(4-)and the heterocyclicring of A that makes H(5),H(6)and H(1')in the UTP~(4-)shift upfield signifi-cantly.Accordingly,the order of aromatic-ring interaction in the mixed-ligand complex has been obtained as follows:Pd(phen)(UTP)~(2-)(?)Pd(bpy)(UTP)~(2-)Pd(trp)(UTP)~(3-).     

STUDIES ON BORON COMPOUNDS (Ⅱ)——SYNTHESIS AND PROPERTIES OF BORON CONTAINING BIS(π-ARENE)IRON(Ⅱ)COMPOUNDS

Thirteen bis(π-arene)iron(Ⅱ) compounds were synthesized.They are [Ar FelB12H12 (Ar=C6H6 MeC6H5;EtC6H5;n-PrC6H5;t-Pr-C6H5 and These compounds have all been identified by elemental analysis and IR spectra,some of them by MS and H NMR.The thermal behavior of these compounds has been investigated by DTA-TG method and IR spectroscopy,and their thermal stability was described.     

STUDIES ON RESPONSE CHARACTERISTICS OF DRUG ISE''''S (Ⅶ)——PERFORMANCE AND THEORETICAL TREATMENT OF MICROCELLS CONNECTED IN SERIES

A new type of MCCS (microcells connected in series) has been constructed and its performances investigated. It has been applied to the determination of streptomycin. The sensitivity and accuracy have been increased significantly. A theoretical model for the error of determination using the MCCS has been suggested and proved experimentally using the Monte Carlo method, and the error model proposed in Ref. [1] revised.     

SYNTHESES OF POLYMER-BOUND RHODIUM COMPLEXES AND THEIR APPLICATION AS CATALYSTS FOR THE HYDROFORMYLATION OF DIISOBUTYLENE (Ⅱ)

Five kinds of polymer-anchored aminophosphine-rhodium complexes were synthesizedby ionic and covalent bonding methods. These anehored rhodium complexes synthesizedpossess good catalytic activity and aldehyde-formation selectivity in the hydroformylationof diisobutylene. The complexes anchored via covalent bonds on polymers showedexcellent reproducibility on recycling. After reaction, it indicated that the loss of rhodiumof the catalysts was very small as shown by analysis.     

STUDY ON THE FORMATIONAL MECHANISM OF THE NORTHERN YELLOW (Huanghai) SEA COLD WATER MASS (Ⅱ)——DISCUSSION ON THE SOLUTION OF THE MODEL

The theoretical solution of the model of the Northern Yellow (Huanghai) Sea Cold Water Mass (NYSCWM) reveals that the NYSCWM is mainly formed through the continuous temperature increase of the overwintered water body above the Northern Yellow Sea Depression (NYSD) after spring when heat is continuously conducted from the sea surface to the'deeper layer. In the NYSCWM's growing period, (June-July), nonlinear, vertical convection and advection effects continuously increase, and are gradually balanced by the heat diffusion effect as the temperature increases from the surface to the bottom, which leads to the formation of an intensive thermocline and lateral front. Meanwhile, the three-dimensional circulation correspondingly occurs. In the NYSCWM's entire growing period, the horizontal circulation is always in the cyclonic motion, while the vertical circulation passes through a transition from a period with the cold centre as downwelling to a period with the cold centre as upwelling.     

STUDIES ON HETERO-MACROCYCLIC POLYETHER (Ⅱ). THE SYNTHESIS OF PLATINUM COMPLEX OF 10-SELENABENZO-15-CROWN-5 AND ITS CATALYTIC BEHAVIOR IN HYDROSILYLATION

The title complex (PtL_2Cl_2) was synthesized by reacting 10-selenabenzo-15-crown-5 (L) with potassium chloroplatinite. Its catalytic activity for the hydrosilylation of olefins by triethoxysilane, was investi gated.     

SYNTHETIC STUDIES ON BLOOD COMPATIBLE BIOMATERIALSⅡ. SYNTHESIS OF POLY(ETHYLENEGLYCOL MONOMETHYLLTHER ) METHACRYLATE AND ANTITHROMBOGENICITY OF ITS COPOLYMERS

Poly (ethyleneglycol monomethylether) methacrylate (PEGMM)was synthesized by means of the reaction of methacrylyl chloride with sodium monomethylpolyethyleneglycoxide and was characterized by FTIR, ~1H-NMR,and ultraviolet spectrometries. A series of poly (vinyl alcohol)-graft-PEGMM (PVA-g-PEGMM )and methyl methacrylate-PEGMM copolymer (PMMA-PEGMM) were prepared and tested for antithrombogenicity in vitro. The results indicate that the antithrombogenicity of the copolymers basically increases with the increasing of the DP of polyoxyethylene (POE) chain and tends to a plateau after the DP around 114,i.e. the long chain structure of POE is favourable to the antithrombogenicityof its copolymers ;moreover, the extent of the improvement ofantithrombogenicity also relates to the PEGMM content of the copolymers and the kind of the matrix that the POE chains are located on. These results are consistent with the anticipation of the hypothesis of maintaining proteins normal conformations for blood compatible bioraaterials.