THE STRUCTURE OF ACTIVE SITE AND THE ROLE OF BIVALENT CATION IN FERRITE-FERRIC OXIDE CATALYSTS FOR OXIDATIVE DEHYDROGENATION OF BUTENES

The relations between catalytic activities and compositions of the systems Mg_xZn_(1-x)Fe_2O_4, Co_xZn_(1-x)Fe_2O_4, Co_xMg_(1-x)Fe_2O_4, Cd_xZn_(1-x)Fe_2O_4 and Mg_xZn_(1-x)Fe_2O_4·0.17Fe_2O_3 have been studied by flow differential reactor, XRD, and derivative IR techniques. It has been found that the appropriate normal-inverse spinel combination substantially increases the activity for the title raction. The structure of the active site and the role of the bivalent cation in the title catalyst have been inferred.     

Specific hydrolysis of DNA by Ce~(4+) -ODN hybrid

The cerium complex bound to the derivative of oligoDNA has been synthesized successfully that can hydrolyze DNA with sequence-specificity. The synthesized derivative of oligoDNA, 5'-EDTA-P-10 mers ODN, was demonstrated by HPLC. The fluorescence spectrum of Tb3+ was detected after its interaction with the hybrid of 10-mers ODN and 26-mers ODN and the results show that the artificial endo-enzyme can recognize and combine firmly with the substrate DNA. The electrophorogram shows that the cerium-oligoDNA hybrid can specifically hydrolyze its substrate DNA and the cleavage site of this hydrolysis reaction is also discussed. This artificial nuclease can be widely used in molecular biology and genetic engineering as one kind of endo-enzyme.     

IDENTIFICATION OF DYNAMIC BEHAVIOUR OF LIGHT-POTENTIAL TRANSDUCTION SYSTEM IN PHOTORECEPTOR OF CALLIPHORA ERYTHROCEPHALA USING IRS-STIMULI

The linear dynamic behaviour of the light-potential transduction system in photorceeptor of Calliphora erythrocephala has been studied through the cross-correlation method using InverseRepeat Sequences and the lineal model of phototransduction is provided. The impulse response function and frequency characteristics have been determiued in the condition of background illumination.The results suggest that the R1-6 is equipped with a gain and time constant control mechanism which depends upon the adaptation level of the system under study.It becomes evident that the IRS correlation method is powerful to quantify the dynamic characteristics of the system containing nonlinearities and will become a very popular application for the study of biological sensory systems.The visual receptor cells R1-6 in the fly are the most sensible choice for the study of the light-potential transdnction system of the eye. The input of the system is the temporarily varying light intensity applied upon the eyes of the fly and th     

EFFECT OF THE COMPOSITION OF m-CRESOL/H2O SOLVENT ON HYDRODYNAMIC PROPERTIES OF NYLON 6

The intrinsic viscosity [ η], Huggins constant (KH), [ η]0, α3 and flow activation energy values of nylon 6 have been measured in water/m-cresol (0/100-20/80) systems at different temperatures (20-60℃). It has been found that the intrinsic viscosity, [η]0 and α3 increase with the increase in water contents in m-cresol up to 15% and then decrease. They increase with the increase in temperature irrespective of solvent composition. It has been noted that the percent increase of α3 is the highest at 60℃ and the lowest at 20℃ for a particular solvent system. The intrinsic viscosity data obey Arrhenius equation over the considered conditions. The activation energy and the KH values decrease very sharply with the addition of water,giving a minimum value at 15% of water and then increase slowly. The variation of all the parameters has been explained in terms of variation in thermodynamic quality of solvent with the addition of water to m-cresol and change in temperature,resulting in the change of conformational and orientational properties of polymer molecules. This change of solvent quality also results in variation of selective sorption of solvent over the polymer, such as hydrogen bonding, etc.     

GEOCHEMISTRY OF PRE-MESOZOIC GOLDBEARING FORMATIONS IN SHAOXINGLONGQUAN UPLIFT REGION, ZHEJIANG PROVINCE

The geochemistry of the main country rocks of gold deposits in Shaoxing-Longquan uplift region has been systematically studied in this paper. The authors believe that the Proternzoic Shuangxiwu group is the primary gold-bearing formation in this region and the Sinian-Cambrian Chencai group and the Precambrian Zuoxi migmatized quartz-diorite are the derivative gold-bearing formations. The genesis of rocks, content distribution features of gold and silver, characteristics of associated trace elements and other geochemical features in these formations clearly show a relationship of inheritance with evolution. By means of metamorphic-solution and volcanic-solution or/and other geological actions, these gold-bearing formations supplied the necessary ore-forming materials for the gold deposits in this region.     

MICELLAR CATALYSIS-THE KINETICS OF Ni(Ⅱ)AND PYRIDYLAZO DYES COMPLEX FORMATION IN THE PRESENCE OF SODIUM DODECYL SULFATE MICELLES

By means of the Stopped—Flow Spectrophotometry,the kinetics of the reactions betweennickel(Ⅱ)and the ligand 5—bromopyridylazo diethylaminophenol(5-BrPADAP)and 3,5—dibromopyridylazo diethylaminophenol(3,5—2BrPADAP)have been investigated in themicellar solution of sodium dodecyl sulfate(SDS).The reaction rate(compared with thatmeasured in aqueous solution for the same Ni~(2+)concentration)was enhanced up to a factorof 400.Kinetic analysis indicates that the rate enhancement can be explained in terms of theconcentration effect of the micelles on the rcactants(i.e.partitioning coefficient effects).Aquantitative expression for the rate enhancement is derived,using the psudo—phase modeland Berezin’s original micellar-catalysis coneepts.The influenccs of hydrophobic character-istics of ligands on the micellar-catalysis effect have been studied also.     

REACTION MECHANISM OF BENZOPHENONE-PHOTOINITIATED CROSSLINKING OF POLYETHYLENE

The radical intermediates, the crosslink microstructures, and the reaction mechanism of benzophenone (BP)-photoinitiated crosslinking of low-density polyethylene (LDPE) and model compounds (MD) have been reviewed in detail.The spin-trapping electron spin resonance (ESR) spectra obtained from the LDPE/BP systems with spin-trap agents showthat two kinds of polymer radical intermediates are mainly formed: tertiary carbon and secondary carbon radicals. The spin-trapping ESR studies of MD/BP systems give further evidence that photocrosslinking reactions of PE predominantly takeplace at sites of tertiary carbon, secondary carbon, and especially allylic carbon when available. The high resolution ~(13)C-NMR spectra obtained from LDPE and MD systems show that the crosslink microstructures have H- and Y-type links andthat their concentrations are of the same order. The fluorescence, ESR ~(13)C and ~1H-NMR spectra from the PE and MDsystems demonstrate that the main photoreduction product of BP(PPB) is benzpinacol formed by the recombination of twodiphenylhydroxymethyl (K·) radical intermediates. Two new PPB products: an isomer of benzpinacol with quinoid structure,1-phenylhydroxymethylene-4-diphenylhydroxymethyl-2, 5-cyclohexadiene and three kinds of α-alkyl-benzhydrols have beendetected and identified. These results provide new experimental evidence for elucidating the reaction mechanism in the BP-photoinitiated crosslinking of polyethylene.     

EFFECT OF SOLVENT ON THE COPOLYMERIZATION OF 2,2,6,6-TETRAMETHYL 4-PIPERIDINYL METHACRYLATE WITH STYRENE

The radical copolymerizations of 2,2,6, 6-tetramethyl 4-piperidinyl methacrylate (TMPM) with styrene in various solvents have been studied. The monomer reactivity ratios r_1 and r_2 were determined. It is observed that in all of these reaction systems, there are appreciable solvent effects on both r_1 and r_2, which can be correlated to the difference in chemical shifts of olefinic protons of TMPM. And the variance of the copolymer microstructure in various media was discussed.     

STUDIES ON GEOCHEMISTRY OF TUNGSTEN-BEARING FORMATIONS IN SOUTH CHINA

The studies on the representative stratigraphic geochemistry have already verified the existence of tungsten-bearing formations in the metallogenetic province of South China. Up till now, it has been established that there are tungsten-bearing formations mainly in the Proterozoic erathem, Cambrian, Devonian and Carboniferous systems. All of them are commonly characterized by high tungsten abundance, certain trace elements combination and distribution type although the tungsten contents of the tungsten-bearing formations are different from the tectonic elements and the passage of time. The preliminary concentration of tungsten in the tungsten-bearing formations has laid the foundation for extensive and diverse tungsten mineralizations in South China.     

AN EXPERIMENTAL SIMULATION ON FORMATION OF SUMMER MONSOON CIRCULATION OVER ASIA——IMPORTANT ROLE OF CROSS-EQUATORIAL CURRENT

In the experimental simulation carried out in a rotating annulus of stratified fluid, theeffects of the cross-equatorial current over the West Indian Ocean, the Tibetan Plateauand different thermal factors have been included according to the similarity requierements.and thus the Asian summer monsoon circulation systems, such as the SW monsoon current,the Indian monsoon depression, the monsoon trough, the Iran high and the shear line overSouth China in the lower-middle layer, and the Tibetan high and easterlies over South Asiain the upper layer, have been well simulated. The experimental results show that the cross-equatorial current over the West IndianOcean plays a key role in the formation of the Asian monsoon systems. The SW monsoonis directly and originally evolved from it. In addition, together with the NE current inthe southeastern part of the Iran high, it composes the cyclonic shear flow situation, andthus provides an important background for the formation of monsoon depression. Underthese conditions, the latent heat of rainfall and the cooling effect over the surface of theArabian Sea can cause the Indian monsoon depression to further develop. According tothe experimental results in different cases, this paper also sheds light on some of the fun-damental mechanism of monsoon systems.     

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.     

STUDIES ON POLYMERIZATION KINETICS OF METHYL METHACRYLATE AT HIGH CONVERSION

The bulk polymerization of methyl methacrylate which was carried out in a metallic dilatometer and in a differential scanning calorimeter has been studied over the complete course of the reaction. An attempt was made to quantitatively express the relation on the onset of gel effect and the final conversion with polymerization conditions such as temperature, kinds and concentration of initiators. It was demonstrated further that the final conversion of polymerization in homogeneous ideal systems is only dependent upon the reaction temperature.     

THE IONIZATION OF EXCIPLEXES FORMED BY CYANO-CONTAINING OLEFINIC COMPOUNDS AND N,N-DIMETHYL-p-TOLUIDINE

The absorption spectra, fluorescence spectra and photoconduction of some systems com-posed of different cyano-containing olefinic compounds and N, N-dimethyl-p-toluidine (DMT)have been studied in this paper. The experimental results show that the exciplex emissionspectra can be observed when the systems of acrylonitrile (AN) or methacrylonitrile (MAN)with DMT are illuminated, whereas the exciplexes between trans-1, 2,-dicyanocthylene(DCNE) or tetracyanoethylene (TONE) with DMT could not be found from the spectra dueto their large ionization. The measurements of photoconduction provide further a clear andunambiguous evidence for the ionization of the systems mentioned above, and they are thesupplement to the systems studied here.     

SYNTHESIS OF γ-SUBSTITUTED-PROPYLCYCLOTETRASILOXANES AND THEIR EMULSION COPOLYMERIZATION WITH OCTAMETHYLCYCLOTETRASILOXANE*

Four γ-substituted-propylcyclotetrasiloxanes have been synthesized. Emulsion copolymerizations of these cyclosiloxanes with octamethylcyclotetrasiloxane have been carried out both in cationic and anionic emulsion systems. By way of these reactions, stable emulsions of organosilicon polymers which contain carbonfuctional groups such as γ-hydroxypropyl, γ-acetoxypropyl and γ-chloropropyi have been obtained.The effects of temperature, catalyst and the amount of γ-substituted-propylcyclotetrasiloxanes in emulsion copolymerizations have been studied.     

STEADY-STATE AND TIME-RESOLVED FLUORESCENCE STUDY OF TRIPLE EXCIPLEX IN THE SYSTEM OF POLYACENAPHTHALENE AND TEREPHTHALIC DIMETHYLESTER

Triple exciplex formed between polyacenaphthalene and terephthalic dimethylester (TDE) has been studied by means of the steady-state and time-resolved fluorescence spectra. The theoretical model of the triple exciplex formation for a flexible polymer chain in a dilute solution has been proposed. The fluorescence decays of the monomer, the exciplex and the triple exciplex obey a double exponential rule in the pbotophysical processes of the triple exciplex formation. The association rate constant of the exciplex formation is k_3=6.0×10~9s~(-1)(mol/L)~(-1); the association rate constant of the triple exciplex formation is k_6=5.2×10~7s~(-1). A mechanism for the triple exciplex formation from the exciplex to the triple exciplex has been proved through the noncrystal films corresponding to the same concentrations of the solution systems and the fluorescence lifetimes of the intramolecular excimer.     

ANALYSIS OF ETHACRYNIC ACID IN URINE BY HPLC-FLUORESEENCE DETECTOR

A sensitive and selective method has been developed for the detection of free ethacrynic acid in human urine. Using 4-(bromomethyl)-7-methoxycoumarin, ethacrynic acid was transformed into a fluorescent derivative, and was analysed by HPLC-fluorescence detector. The detection limit is 0.1ug/ml urine. The method is suitable for screening ethacrynic acid in doping control and studying its metabolism.     

CATALYTIC ACTIVITY OF Pd-Sn COMPLEX CARBONYLATION OF ACETYLENE

The influence of different concentration of HO, SnCl2, Cl- and n-BuOH on the carbonylation of acetylene has been studied. The results show that the yield of n- butyl propionate increases with the increase of HC1 concentration and the catalytic activity is depressed when Cl" concentration increases. However, the stability of catalytic complex is promoted by Cl-. The key to the carbonylation of acetylene lies in the addition of SnCl2, which promotes the formation of the complex of C2H2, CO with catalyst and plays an important role in the hydrogen removal from n-BuOH. The hydrogen removed from n BuOH is the hydrogen source of this reaction. Meanwhile, the principle of the effect of HCl, Cl- and SnCl2 on reaction has been discussed. The reaction model has also been proposed.     

EXPERIMENTAL STUDY ON REMOTE SENSING OF ATMOSPHERIC SOUNDING BY MEANS OF MULTIFREQUENCY MICROWAVE RADIOMETERS

In this paper, the principle and method of microwave remote sensing atmospheric sounding are described. In order to carry out the experimental study, the 4 channels in 5mm—1.35 cm band microwave radiometers have been constructed. The field experiment in September-October 1981 was carried out. In this paper, the results obtained by different inversion methods are compared with each other. The experimental result shows that it will be satisfactory, if the temperature profile and inversion of lower atmosphere are derived from remote sensing of 2 channels (frequencies: 52.8 Gc and 54.4. Gc) in 5 mm band. The atmospheric humidity can be obtained from the remote sensing of 1.35 cm band. While the change of air mass exists, signal reveals itself significantly in the atmospheric microwave radiation. The variations of atmospheric temperature and humidity have been analysed and compared with those obtained from radiosonde.     

SPIN-LABELED ANTITUMOR DERIVATIVES OF PODOPHYLLOTOXIN

Three spin-labeled antitumor derivatives of podophyllotoxin, containing an iminoxyl radical,have been synthesized.Preliminary pharmacological tests showed that these derivatives have significant antitumor activity in several experimental tumor systems with a marked decrease in toxicity compared with the parent compound.The relative intensities of ESR signals of these spin-labeled compounds were linearly proportional to their concentrations, the levels of the agent in blood and organs of mice or rabbits can be measured via ESR spectrometry.