PHOTOELECTROCHEMICAL BEHAVIOR OF POLYANILINE FILM

The photoelectrochemical behavior of polyaniline(PAn)filmwas studied in aqueous electrolyte solution containing Fe(CN)_6~(3-)/Fe(CN)_+~(4-)redox couple.It was found that PAn films possess the properties of p-typesemiconducter and a cathodic photocurrent as high as 700μA/cm~2 was observedwhen irradiated under polychromatic light of 100mW/cm~2.     

THE PHOTOPOLYMERIZATION KINETICS OF PHOTOSENSITIZED ACRYLAMIDE SYSTEM INDUCED BY He-Ne LASER

The kinetics of the photopolymerization of sensitized acrylamide (AM) system induced by He-Ne laser has been investigated. Using methylene blue (MB)-triethanolamine (TEOA) as the photosensitive system, the photopolymerization followed a nonsteady-state kinetic scheme in the initial period of polymerization (the monomer conversion C%<2%) and then followed a steady-state kinetic scheme (5% >C%>2%). Accirding to the steady-state hypothesis, the mechanism of photopolymerization was proposed. The deduced kinetic equation of the photopolymerization of AM is in good coincidence with the experimental results.     

PHOTOPOLYMERIZATION IN THE MICELLAR SYSTEMS Ⅳ THE PHOTOSENSITIZATION EFFECTS OF THE BENZOPHENONES WITH DIFFERENT CHARGE IN IONIC MICELLAR SYSTEMS*

The photosensitization effects of the benzophenone derivatives having different charges, such as cationic BP(BP—CH_2—N~+ (C_2H_5)_3Br~-) (PKT-1), anionic BP(BP—COONa) and the neutral BP in the various ionic micellar systems were studied. From the photopolymerization of MMA initiated by the various BP/TEA in different micellar systems, the results obtained show that the polymerization rate is in the order of PKT-1>BP>BP—COONa in the SDS anionic micelle. On the contrary, the order changes to BP—COONa>BP>PKT-1 in the CTAB cationic mieelle, and to BP—COONa≈PKT-1>BP in the PKT-3 functional micelle. It is noteworthy that the PKT-1/SDS system is more efficient with its quantum yield more than 50 times compared with that of simple BP/H_2O system.     

INVESTIGATION ON SYNTHESIS OF OXALIC ESTER THROUGH OXIDATION CARBONYLATION OF ALCOHOL UNDER MILD CONDITIONS

We here report a new approach of oxalic ester synthesis through ox-idation carbonylation of alcohol in the presence of new bimetal complex systemsunder mild conditions. By suggesting that the active complex (PPh_3)_2Pd(OAC)_2/OV (acac)_2 and the oxalic ester are produced through the coupling ofthe alkoxyl-carbonyl-palladium complex as intermediate, the mechanism of theformation of diethyl oxalic ester via the coupling of CO with C_2H_5OH is pro-posed.     

SYNTHESIS OF LANSFORDITE MgCO_3·5H_2O AND ITS CRYSTAL STRUCTURE INVESTIGATION

Euhedral crystals of the uncommon low-temperature mineral lansfordite have been obtained by the synthetic method, and the crystal structure analysis has been accomplished correspondingly. The structural parameters and the general view of structure were presented for the first time. The results obtained show that the coordination configuration of two magnesium ions in the unit cell is octahedral arrangement and the coordination number is 6, but in two forms: one in the complex ion Mg(CO_3)_2(H_2O)_4~(2-) and the other in the Mg(H_2O)_6~(2+). There is only a CO_3~(2-) group in the structure, not three distinct groups as reported by Hill et al. previously based on the IR absorption spectrum research data. The authors of this paper believe that the exact chemical formula of lansfordite should be expressed as "Mg(H_2O)_6. Mg(CO_3)_2 (H_2O)_4", and MgCO_3-5H_2O is only a simple chemical expression.     

RADICAL PHOTOPOLYMERIZATION USING ARYLIODONIUM SALT/TERTIARY AMINE COMPLEX SYSTEM AS THE PHOTOINITIATOR

The diphenyliodonium salt (DPIOC)/triethylamine (TEA) is used as photoinitiator for radical photopolymerization. It was found that a ground state CT complex formed between DPIOC as electron acceptor and TEA as electron donor, which results in extending the photosensitivity range of DPIOC/TEA system up to above 500nm compared with DPIOC alone. The kinetic studies on photopolymerization of methyl methacrylate (MMA) were carried out in CH_3CN: H_2O (14: 1, v/v) mixture solution at 30℃by dilatometer. The results obtained show that the polymerization rate (R_p) increases with increasing concentrations of DPIOC and TEA with exponent 0. 65 and 0. 62 respectively. The activation energy E_a and k_p/k_~(1/2) value were determined to be 4.1 Kcal mol~(-1) and 0.045 respectively. The other influence factors and reaction mechanism were also discussed.     

MICROSCOPIC MECHANISM OF STRENGTH REDUCTION OF ROCKS

Uniaxial compression tests have been conducted on Jinan gabbro at six different axial strain rates ranging from 10~(-8)/s to 10~(-3)/s. Results show that the strength decreases by about 23% with decreasing strain rate. The stress level C_0~' /or the onset of dilatancy is constant for six strain rates. When σ_1>C_o~' ε_1 and D increase with decreasing strain rate (?) under a specific stress level.Microscopic observations on the stressed rock samples reveal that the density of microcracks for the samples loaded at low strain rates is higher than that at high strain rates; in addition there are also cracks nearly perpendicular to it, which is responsible for the increase of D value.The creep test under the stress σ_(σ_1>C_0~') confirms that the growth of microcracks in the rock has been time-dependent effects, and the steady-state creep with (?)=constant developed until the rock fails.Summing up the above reslts shows that when σ>C_0~', the constitution law of the rockswill be time-dependent, and the     

THE STATE OF CHROMIUM (Ⅲ) ION IN AQUEOUS SOLUTION

So far few systematic studies on the hydrolytic polymerization of Cr(Ⅲ) were reported because of inertness of the ion and complication of the process. We studied it in equilibrium by pH method systematically in a wide concentration range (0.0002—0.32 M). The results show that, in the low concentration range, the composition of the polynuclear hydrolysis products may be represented as [Cr_3(OH)_4] (OH)_n (n=1,2,3); in the medium range, the composition of products as Cr[Cr(OH)_2]_n~((3+n))~+ (n=1,2,3); in the high range, the composition of products as Cr[Gr(OH)]_n~((3+2n))~+ (n=1, 2), and in the intermediate range between medium and high range where the hydrolysis system is in a transition state, the composition of products as [Cr_3(OH)_3]~(6+) and [Cr_3(OH)_4]~(5+). The values of hydrolysis constants of the identical species measured in different Cr concentration ranges and calculated by different methods were found in good agreement with each other. A predominance-arca diagram was made by using the hy     

STUDIES ON THE PHOTOPOLYMERIZATION OF ACRYLONITRILE INITIATED BY BENZOPHENONE-ANILINE SYSTEM

The photopolymerization of acrylonitrile initiated by benzophenone-aniline system wasstudied under the irradiation at 365 nm. From the kinetic data measured in dimethylforma-mide the kinetic equation was presented as R_p∞[benzophenone]~(0.32) [aniline]~(0.27) [acryloni-trile]~(1.1). The rate of polymerization for different amines was in the following sequence, i.e.N, N-dimethylaniline>N-methylaniline>aniline. The influence of the polarity of solventwas investigated, from which we proposed that the proton transfer took place in the intimateradical-ion pair state of the exciplex between benzophenone and aniline. Among the twokinds of radicals produced the anilino radical is responsible for the initiation.     

SYNTHESIS AND CHARACTERIZATION OF BLOCK POLYMER OF ALTERNATING COPOLYMERS

Block polymer of alternating copolymers, poly[(ST-a-MA)-b(IP-a-MMA)-b-(ST-a-MA)](I), has been synthesized in the presence of AlEt_(1.5)Cl_(1.5),by using Mn_2(CO)_(10)/CBr_4. initiation system.The GPC results indicate that there is no unreacted prepolymer in I purified by precipitation andfractionation. The study of NMR shows that every block of polymer I has alternating structure. The dynamicmechanical properties of I measured by torsional braid method indicate that the polymer has two T_g s,being 38 and 75℃, respectively. The transmission electron micrographs of I show they have two phasestructure and the domain size increases with increasing molecular weight of hard block.     

INFLUENCES OF LIGANDS ON THE HOMOGENEOUS HYDROFORMYLATION OF ALKENE(I)-TRI-(3,4-DIMETHYLPHENYL)PHOSPHITE AS A LIGAND

In this paper we describe the effects of tri(3, 4-dimethylphenyl)phosphite[(3,4-(CH_3)_2C_6H_3O)_3P]or triphenylphosphine(PPh_3)used as ligand in the homogeneoushydroformylation of alkene using dicarbonyl acetylacetone rhodium as the parent catalyst.The reaction kineties has been investigated.It was found that tri(3,4-dimethylphenyl)-phosphite has greater activity and better selcctivity than PPh_3 for hydroformylation ofheptene-1.The results are discussed in terms of eiectronic and stereochemical effects.     

THE REFINEMENT OF CRYSTAL STRUCTURE OF BALIPHOLITE

Balipholite is a new mineral discovered in China. Its space group is C cca with the lattice parameters a=13.587(6), b=20.164(10), c=5.144(1). The structure was refined to an R value of 0.047 for 949 independent reflections with (|F_0|>3σ|F_0|). Balipholite has the simailar structure as that of the carpholite group but with large cations Ba occupying the caves of the structure. It is very interesting to point out that the additional anions F and OH occupy different crystallographic positions. Formula of balipolite can he written a BaMg_2LiAl_3(Si_2O_6)_2(OH)_4F_4.     

Combining photo-cleavable and hydrogen-abstracting groups in quinoxaline with thioether bond as hybrid photoinitiator

We synthesized four diphenylquinoxaline derivatives(SQs) with phenyl-thioether units, which combine photo-cleavable and hydrogen-abstracting groups in one molecule. The photochemistry and photopolymerization of SQs were investigated. SQs possess suitable UV-vis absorption in the range of 350-400 nm with high extinction coefficients. UV-vis and HPLC-MS spectra revealed that C–S bond in phenyl-thioether group of SQs can be broken by irradiation of UV-light. Photolysis and photopolymerization experiments showed that SQs can be used as photo-cleavable photointiators,their photoinitiating efficiency can be enhanced by hydrogen donor. As photo-cleavable photoinitiators,SQs could initiate hexamethylene diacrylate(HDDA) very efficiently with the double bond conversion(DBC) of 80%. In the presence of ethyl-4-(dimethylamino) benzoate(EDB) as coinitiator, photoinitiator systems initiated photopolymerization of commercial acrylate monomers with higher double bond conversion than 90%. These characteristics make SQs potential photoinitiators in photo-curing field.     

DETERMINATION OF SOLUBILITY OF Fe_2O_3 IN DILUTE AQUEOUS SOLUTIONS AT 300℃ AND 10 MPa——APPENDING A DISCUSSION ABOUT THE TRANSPORTING FORM OF IRON IN HYDROTHERMAL SOLUTIONS

The solubility of Fe_2O_3 in dilute KOH and HClO_4 aqueous solutions was determined at 300℃ and 10 MPa. The analysis of the solubility data indicated that in neutral and alkaline hydrothermal solutions iron mostly existed as Fe(OH)_3~0 and Fe(OH)_4~-, and it was calculated that △G_(Fe(OH)_3~0)~0=-561.9±3.3kJ/mol, and △G_(Fe(OH)_4~0)~0=-662.7±5.0 kJ/mol at 300℃. According to the analysis on the previous experimental studies about the transporting form of iron, the existing form of iron in hydrothermal solutions is discussed in this paper.     

THE EFEFCT OF MAGNETIC FIELD ON POLYMERIZATION OF STYRENE IN THE PRESENCE OF POLYVINYL NAPHTHALENE AND POLYVINYL BENZOPHENONE

In the process of bulk photopolymerization of styrene initiated by AIBN decomposition polyvinyl benzophenone (PVB) can supply an effective cage for triplet-triplet energy transfer between PVB macromolecules and small molecules of AIBN to influence the molecular weight of polystyrene in weak magnetic field (less than 0.035T), that was different from the case of polyvinyl naphthalene (PVN) which supplied cages for this system only in the stronger magnetic field (more than 0.2 T) studies. It was found that in the same conditions, PVN could exert more tremendous influences on the bulk photopolymerizatiou system of styrene than PVB because in the stronger magnetic field the triplet PVN had much longer life time than PVB.     

THE SYNTHESIS AND CHARACTERIZATION OF Ba-CROSSLINKED POLYMER ANTI-RADIATION MATERIALS

Crosslinked poly(methyl methacrylate) and polystyrene with barium dimethacrylate [Ba(MA)_2] as crosslinking agent have been synthesized. The relationship between X-ray absorbability and the content of Ba(MA)_2 in polymers was investigated. TGA and DSC results indicated that the crosslinked polymers containing barium dimethacrylate have a much better heat stability than pure PMMA or PS. The mechanical properties of the polymers containing barium are improved in comparison with the pure PMMA.     

THE SPECTRA OF BAROTROPIC QUASIGEOSTROPHIC MODEL AND THE EVOLUTION OF DISTURBANCES

The spectra of linearized barotropic quasigeostrophic model is one of classical but not yet completelysolved problems in dynamic meteorology. This paper is devoted to a detailed investigation of this problem.It is obtained that in the case of zonal basic flow μ(y), there exist two types of spectra, the discrete andcontinuous. Each discrete spectrum (eigenvalue) gives an eigenfunction (normal mode); and the real num-bers in the interval [μ_(min), μ_(max)] are the continuous spectra; every point c ? [μ_(min), μ_(max)] gives a spectralfunction which is bounded and whose derivative is unbounded but integrable. Every disturbance can berepresented as a linear combination of two parts, ψ'(x, y, t) and ψ'(x, y, t), the former is expressed bythe discrete spectra, and the latter by the continuum. ψ'_d can be easily derived from the initial conditionby the use of the generalized "weighted orthogonality" of normal modes. It is also proved that ψ'_c as wellas its energy E'_c and mean y-direction scale l_c a     

STUDIES ON THE MECHANISM OF VINYL PHOTOPOLYMERIZATION INITIATED BY CONDENSED AROMATIC HYDROCARBON-ANILINE SYSTEMS

Initiation mechanism of the photopolymerization of acrylonitrile and methyl methacrylate, usingbinary condensed aromatic hydrocarbon (CAH)-aniline systems as initiator, was studied. The strongerthe electron-donating ability of the aniline derivatives, the faster the the of photopolymerizationwill be. The radical intermediates produced by photoreaction between anthracene and anilinewere detected with ESR spectra. The initiation scheme involves the formation of exciplex betweenthe excited singlet state of CAH and the ground state of aniline as the first step, and then followedby proton transfer, leading to the generation of two kinds of radicals. From the end-group analysisof the polymers obtained, it is suggested that both kinds of radicals are involved in the initiation.     

COMPARATIVE STUDY ON RESIDUAL EFFECTS OF ORGANIC AND INORGANIC FERTILIZER NITROGEN IN WATERLOGGED SOIL AND DRYLAND SOIL

The balance of residual fertilizer nitrogen was studied with the application of crotalariaand ammonium sulfate in two opposite cropping sequences —rice-wheat-rice-wheat and wheatrice-wheat-rice. Air-dried plant of crotalaria tagged with(~(15)NH_4)_2SO_4 and containing 6.5% of ~(15)N in total nitrogen was used as the sources of ~(15)N labelled organic manure. Ammonium sulfate tagged with 10.6% ~(15)N was applied as inorganic fertilizer.The recovery rate of residual fertilizer N was very low, averaging only 2.5% 2% on the basis of applied fertilizer N, in the case of rice as well as wheat in each successive cropping season. After the harvest of the first crop, more fertilizer nitrogen was immobilized as residual form in dryland soil than in waterlogged soil. The percentage of cumulative uptake of fertilizer N in rice-wheat-rice-wheat cropping sequence was much greater than that in the wheat-rice-wheat-rice sequence. It might be more economical to apply this kind of manure as basal dressing first to rice.     

STUDIES ON THE PHOTOCHEMICAL REACTION OF TERTIARY AROMATIC AMINES AND ALIPHATIC HALIDES——STRUCTURE OF THE PRODUCT AND MECHANISM OF THE REACTION

The photochemical reaction of aromatic amines in the presence of aliphatic halides and molecular oxygen were studied. There is a very obvious structural effect of amines on the photoreactions, and the purple products, formed only in the tertiary aromatic amines system, were proved to be amiuium radical salts, e. g. CH_3—(CH_3)_2Cl-by moans of UV, NMR and ESR spectroscopies electronic conductivity and chemical analysis. The purple product can oxidize the adrenaline to adrenochrome. The mechanism of the photoreaction and the oxidation were discussed.