OXYGEN ISOTOPE COMPOSITIONS OF SEAWATERS IN THE HUANGHAI(YELLOW) SEA AND THE BOHAI SEA

The characteristics of oxygen isotope compositions and distributions of the seawaters inthe Huanghai(Yellow) Sea and the Bohai Sea have been investigated based on δ~(18)O data meas-ured for 608 water samples. By using the property of tracing atoms, the mixing and theinfluencing range of the diluted freshwater of the Huanghe (Yellow) River and the exhibitionof δ~(18)O values in the movements of the Huanghai Sea warm current and its residual flowshave been discussed. Particularly, the regional, vertical, seasonal and tidal changes of the δ~(18)Ovalues of the waters influenced by the Huanghe River have also been studied. A beneficialexploration was thus made for the application of stable isotope to the physical oceanography.     

ISOTOPIC GEOCHEMISTRY OF FOSSIL FUELS IN CHINA

The authors have summarized the results of their study on the isotopic composition ofChina's fossil fuels for the past 20 years. Comparatively speaking, the main frequency of thedistribution of the δ~(13)C value for coal is from -25.5 to -23.5%. The effects of thermalevolution might be neglected, however, it is obvious that the coal macerals have an effecton the δ~(13)C value. The δ~(13)C of whole coal becomes lighter with the exinite content increasing.Our studies of thermoanalogue products from coal measures show that gaseous hydrocarbonhas the lightest δ~(13)C value at the peak value which produces liquid hydrocarbon. It is similarto the δ~(13)C of coal samples. The alkane in group fraction changes more significantly with theincrease of temperature. The type of biothermocatalytic transitional zone gas might be dividedaccording to the δ~(13)C and δD research of natural gas. The δD of methane becomes heavier withthe increase of water-medium salinity. The isotopic research on light hydrocarbon m     

STUDIES ON REGULARITY OF POLY PHENYLSILSESQUIOXANE CHAINS

IR and ~(29)Si NMR were used to determine the structures of ladderlike polymer polyphenylsilsesquioxanes (PPS). It was found that PPS with lots of defects had a wide and strong absorption band in 1000—1400 cm~(-1) with only one sharp peak at 1137 cm~(-1) while two peaks (1130 and 1045 cm~(-1) were observed for PPS with perfect ladderlike structure. Branching and crosslinking of PPS lead to the reduction of 1045 cm~(-1) peak. ~(29)Si NMR spectra, however, showed two peaks (δ=-78 ppm and -87 ppm when δ_(HMDS)=0 ppm) for defective or branched PPS. The -87 ppm peak is related to the ladderlikely constructed Si atoms and -78 ppm corresponds to defective Si atoms. PPS with defects less than 0.1% chain units was obtained by azeotropic polycondensations.     

PROPERTIES OF CHICKEN LIVER PHOSPHOFRUCTOKINASE-2

Phosphofructokinase-2 was purified to homogeneity from chicken livers by homogeniza-tion, polyethylene glycol fractionation and column chromatography on DEAE-Sephadex A-50 and Blue-Sepharose 4B. Some properties of the enzyme were as follows: (i) The saturation curve of the enzyme for fructose 6-phosphate showed hyperbolic and the Km of fructose 6-phosphate was affected by inorganic phosphate while Vmax was not; (ii) the binding of ATP to the enzyme was of negative cooperativity with a Hill coefficient of 0.56; (iii) the activity of the enzyme was completely lost in the presence of EDTA. The enzyme was activated by Mg2+ at low concentrations, but inhibited by Mg2+ at high concentrations; (iv) the enzyme was stable below 30℃ and easily lost its activity when the temperature was above 40℃; (v) the activity of the enzyme was stable at the range of pH 7-9, increased at pH 9.0-9.5 and decreased when pH was over 9.5; (vi) the enzyme was sensitive to trypsin and ATP protected the enzyme against the proteolysi     

STUDIES ON THE PROPERTIES OF SCHIFF BASE TYPE ARYLMERCURY COMPOUNDS.II ~(199)Hg NMR SPECTRA OF MERCURATED DERIVATIVES OF SUBSTITUTED BENZYLIDENEANILINES

~(199)Hg NHR spectra of 18 Schiff base type arylmercury compounds have beenstudied.It was further confirmed that in the molecule of XC_6H_4CH=NC_6H_3-2-HgC1-4-CH_3there exists an intramolecular N→Hg coordination via a four-membered ring.For theseries of XC_6H_4CH=NC_6H_3-2-HgCl-4-CH_3(X is a para-or mera-substituent),there is agood linear correlation between δ~(199)Hg and Hammett's o constants.The influence ofsubstituents of C-pheny1 ring on the δ ~(199)Hg can be explained in terms of theintramolecular N→Hg coordination.     

THE ALTITUDE AND LATITUDE EFFECTS OF H-O ISOTOPIC SYSTEM IN GRANITOID ROCKS

A lot of Mesozoic and Cenozoic granitoid rocks are widely distributed along the east coastalregion and in the southern part of Xizang, China. In order to study the altitude and latitude effect ofH-O isotopic system in these granitoid rocks, we have first studied the altitude and latitude effects ofδ~(18)O, δD values of recent meteoric water. The altitude and latitude effect equations of recent meteoricteoric water were established. The altitude effects of δD vaues for hydroxyl minerals from granitoid rocks inLhasa-Yadong region of Xizang were found. The average elevated rate of Xizang Plateau is 0.1 mm/yr.The δ~(18)O and δD values of whole rock samples for late Yanshanian miarolitic granite in the east coastalregion wete progressively lower as a function of latitude. The negative correlation between δ~(18)O and δDvalues in each miarolitic pluton represents the relationship between δ~(18)O, δD values of rocks or mineralsand temperatures in the condition with the same ω/r ratio in the interactiv     

CRYSTAL STRUCTURE OF OXAZOLIDINE-2-THIONE

<正> Crystals of. oxazolidine-2-thione, G3H5SNO, are triclinic,P1, a = 5.738(3), b = 5.928(4), c = 7.763(5) A, (?) = 83.05(6)°, α= 67.68(5)°, r = 77.85(5)°, Z = 2, V = 235.8A3, Dx = 1.45 g.cm-3, P(000) = 108, Mr = 103.14, m.p. = 96.2°-97.2°C, (MoK(?)) = 0.71069A, T = 293K, μ(MoK(?)) =0.051 mm-1. The structure was solved by direct methods and. difference Fourier synthesis. The final R was 0.033 for 655 unique observed reflections. It is a new hydrolysis and rearranging product of 2-hydryoxyl ethyl glucosinolate from the seeds of Copparis masaikai Levl.. The study of its physiological activity is in progress.     

Fe(OH)2悬浮液在EDTA作用下氧气氧化生成δ-FeOOH的机理研究

At room temperature and in the presence of trace EDTA, the formation of δ-FeOOH was studied by the rapid oxidation of Fe(OH)2 suspension with O2. The structural and morphological changes were characterized by various techniques such as XRD, FTIR and TEM. γ-FeOOH and δ-FeOOH formed simutaneously in the early period of oxidation. But as the rate of mass transfer was in equilibrium, trace γ-FeOOH vanished gradually. Accordingly, pure phase δ-FeOOH was obtained. At the same time, critical amount ratio K of EDTA to Fe^2 was verified. The experiments show that the reactivity, rate of the oxidizing agent and pH of the initial medium were important factors for the formation of pure phase δ-FeOOH. Under the auxiliary effect of EDTA, the reactivity of O2 was nearly improved to that of H2O2. And the process of the oxidation that Fe(OH)2 suspension was oxidized by O2 under that condition was discussed.     

HIGH CONDUCTIVITIES OF LANGMUIR-BLODGETT FILMS OF TBT-TTF-NI(DMIT)_2/STEARIC ACID

Conductivities of Langmuir-Blodgett(LB) films of tetrabenzylthio-tetra-thiafulvalence-Ni(dmit)_2/stearic acid (SA)were described. This chargetransfer complex was transferred with SA onto a glass plate coated with A1electrodes. The relation of conductivities of LB films with molar ratio ofSA was studied. The conductivities of LB films of TBT-TTF-Ni(dmit)_2/SA weremeasured under undoped and I_2 doped states. The maximum conductivity ()of LB film was 40s/cm.     

STUDIES OF MULTICOMPONENT COMPLEX OXIDE CATALYSTS FOR THE OXIDATIVE COUPLING OF METHANE Ⅳ CATALYSTS LiLa_(1-x)Mn_xO(2-λ)(X=0-1)

A series of catalysts LiLa_(1-x)Mn_xO_(2-λ)(x=0—1)were examined for the oxidative couplingof methane.A high C_2 yield of 22％ was obtained.The structures and physico-chemical properties ofsamples have been studied by means of XRD,IR,XPS and SEM.It was found that some complex ox-ides could be formed as X value changed,among them the K_2NiF_4-type oxide La_2Mn_(1-y)Li_yO_(4-λ)was theactive phase for methane coupling,while the Li_2MnO_3 and LiMn_2O_4 were the active phases for completeoxidation of re.ethane.The increase of catalytic activity for methane coupling was attributed to theincrease of the amount of active site,namely,oxygen vacancy in oxide La_2Mn_(1-y)Li_yO_(4-λ)     

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.     

TRANSGENIC RICE PLANT OF A SUPERIOR CHINESE CULTIVAR Zhonghua NO. 11 CONTAINING THE B. t. δ-ENDOTOXIN GENE IN ITS GENOME

The B. t. δ-endotoxin protein gene has been transferred into a commercial rice variety Zhonghua No. 11 by the pollen-tube pathway method. The expression of β-glucuronidase activity in the transgenic plant (D_3) was confirmed by histochemical analysis. Since the GUS gene was translationally fused with the B. t. δ-endotoxin protein gene in the recombinant plasmid pGYCK63, the expression of the GUS gene offered evidence for the expression of the δ-endotoxin protein gene in the transgenic rice plant.     

STUDIES ON CYCLOPENT-2-ENONE: (Ⅲ) THE STUDY ON DECONJUGATION OF CYCLOPENT -2-ENONE ALDOL ADDUCTS

Deconjugation of cyclopent-2-enone aldols were attempted under various conditions, and the desired deconjugated product was achieved via dianion approach. Various results obtained in this study are explained by structure and transition state analysis.     

STUDIES ON CRITICAL CONCENTRATION OF LIQUID CRYSTALLINE ETHYLCELLULOSE

Critical concentrations of lyotropic liquid crystalline ethylcellulose in more than tensolvents were determined using both Abbe refractometer and polarized microscopy. Criti-cal concentration C_(crit) of forming liquid crystal phase decreased with increasing solubilityparameter δ of solvent until approaching the δ of polymer. Although the alcohols usedas solvents had the same variation rule, the critical concentration values of their solutionswere much higher, due to their excessive large hydrogen bond component of δ. The experi-ments of using mixed solvents which showed good linear relation between C_(crit) and δ alsoproved this rule. A technique of Transmission Optical Analysis was first used to estimatethe concentration dependence of critical phase transition temperature T_(crit) of EC, and aT-C phase diagram could be drawn.     

TIME-RESOLVED FLUORESCENCE STUDY OF TRIPLE EXCIPLEX FORMED IN THE SYSTEM OF POLY(2-VINYL) NAPHTHALENE AND TEREPHTHALIC DIMETHYLESTER

An intramolecular excimer of poly(2- vinyl) naphthalene was formed by non-adjacentchromophores interaction, then a triple exciplex was formed by interaction with the acceptormolecule further in dilute solution. The lifetime of the intramolecular excimer of poly(2-vinyl) naphthalene, τ_2 = 18.83 ns and the rate constant for the triple exciplex formation,k_7 = 4. 18× 10~9 (mol/L)~(-1)s~(-1), under diffusion-control were measured. An excimer or anexciplex could be an intermediate of the triple exciplex formation. A theoretical model ofthe triple exciplex formation is proposed.     

EFFECT OF TRANSMEMBRANE Ca~(2+) GRADIENT ON CONFORMATION AND ENZYME ACTIVITY OF RECONSTITUTED ADENYLATE CYCLASE

Adenylate cyclase from bovine brain cortex was reconstituted into asolectin liposomes with (500-fold) or without transmembrane Ca~(2+) gradient. The enzyme activity of four types of proteoliposomes (the active center of enzyme exposing outside) was compared. The highest adenylate cyclase activity was observed in the vesicles with outside lower Ca~(2+)concentration (≈10~(-6) mol/L, similar to thephysiological condition). If the transmembrane Ca~(2+) gradient was in the inverse direction (i.e. outside higher Ca~(2+) concentration, 0.5 mmol/L), a lowest enzymatic activity would appear. The difference in enzymatic activity between the two types of proteoliposomes could be diminished following the addition of Ca~(2+) ionophore A23187. Proteoliposomes without transmembrane Ca~(2+) gradient exhibited intermediate activities.The conformation difference of adenylatecyclases in the above-mentioned proteoliposomes was also detected by measuring intrinsic fluorescence and fluorescence quenching with KI.     

STUDIES OF MULTICOMPONENT COMPLEX OXIDE CATALYSTS FOR THE OXIDATIVE COUPLING OF METHANE Ⅲ CATALYSTS LiLa_(1-X)Ni_XO_(2-λ)(X=0-1)

The catalysts LiLa_(1-x)Ni_xO_(2-λ),(x=0-1)were examined systematically for the oxidativecoupling of methane,and the active phase La_2Ni_(1-y)Li_yO_(1-λ)was identified by means of XRD,IR,SEMand so on.A high C_2 yield of 21.5％ with a selectivity of 67.2％ at 1023 K was obtained.The activitytowards C_2 formation arised with the increasing of the amount of active sites,oxygen vacancies Vo,which were formed in the complex oxides La_2Ni_(1-y)Li_yO_(1-λ).     

PREPARATION OF NANOMETER TiO2 ORGANIC SOLUTION —EFFECT OF ORGANIC SILOXANE ON SOL PROPERTIES*

A homogeneous longtime stabilized transparent nanometer TiO2 organic solution was obtained by means of the simultaneous hydrolysis and co-polycodensation of tetrabutyltitanate (TBT) and methacryloxypropyltrimethoxysilane (MAPTMS) by the sol-gel process. The particle size of nanometer titanium dioxide was controlled by use of bifunctional silanes, such as diphenyldimethoxysilane (DPDMS), diphenyldiethoxysilane (DPDES) and dimethyldiethoxysilane (DMDES). The effect of TiO2 content in the solution on the refractive index of system was discussed in detail. The result shows that the refractive index of solution increases linearly with TiO2 content. The refractive index of the three hybrid nanometer materials attained 1.6053, 1.5846 and 1.5346, respectively. The size of nanometer particles was characterized by TEM and the particle diameter thus obtained is in the range of 20-90 nm. FT-IR spectra of the materials show that the TiO-Si bond is formed.     

STUDY OF THE FLUORESCENCE ENHANCEMENT IN THE SYSTEM OF EUROPIUM-OR SAMAR-IUM-TERBIUM-DIBENZOYLMETHANE-CETYLTRIMETHYLAMMONIUM BROMIDE-TRITON X-100 AND ITS APPLICATION

A fluorescence enhancement phenomenon on adding terbium to the Eu or Sm-DBM-CTMAB-Triton X-100 fluorescence system was observed. The fluorescence intensity of this system was 50 times greater than that of the system without terbium at pH 9.0. The fluorescence intensity is a linear function of the concentration of europium or samarium in the range of 1.0×10~(-10)-8.0×10~(-6) mol/L and 1.0×10~(-7)-8.0×10~(-6) mol/L, respectively. The deteetion limits for them were 1.0×10~(-12) mol/L and 1.0×10~(-9) mol/L, respectively. This system was used for the determination of europium or samarium in rare earth samples with satisfactory results.     

CHANGES OF QUATERNARY CLIMATE OF LOESS DISTRICT IN CHINA

On the basis of the data of sporo-pollen analysis, the weathering index of loess and paleosol layers and the climatic differences between the periods of the formation of loess and paleosol as reflected by intensities of natural remanent magnetization of loess and paleosol, it may be confirmed that the loess layers represent the climate of glacial stages, while paleosol was formed during interglacial stages. The climatic changes in the loess area of China have undergone 23 cycles which were combined with the paleomagnetic dating. TL ages of paleosol layers and the average ages of termination could be excellently correlated with the δ~(18)O stages of deep sea core V_(28-239). Thus, it may be recognized that the Luochuan and Xi'an loess-paleosol sequences are the typical climatostratigraphy in China and even in the world.