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1.
The partial oxidation of methane to methanol was studied. The effectof various homogeneous "sensitizers" on the oxidation of pure methane was e-valuated at 433℃ and under a pressure of 5.0MPa. It was found that CH_3NO_2was the best one among them. A kinetic study in the presence of CH_3NO_2 wascarried out and the reaction mechanism was discussed.  相似文献   

2.
Two episodes of paleoredox fluctuation variation are indicated in some localities in thelate Cretaceous--early Tertiary ocean of western Tarim recorded by REE distribution patterns,Ce anomalies, and Th/U ratios from systematic studies on the chemical composition, withspecial reference to REE and 20 trace elements, based on 11 marine shell fossils occurringin the Upper Cretaceous--Lower Tertiary strata of the western Tarim Basin, Xinjiang. Thefactors Controlling the redox fluctuation may be probably caused by shifting places ofsurface runoff put into the sea as a result of transgression and regression.  相似文献   

3.
The determination of an initial model for the crystal structure of des-pentapeptide in-sulin, using only the phase information obtained from the scattering of cadmium ions inthe native crystal, has been described. This paper describes the refinement of this modelagainst both the experimental X-ray observations and the a priori stereochemical observationsusing the method of restrained parameter least squares. The corrected and extended modelincluded not only all the non-hydrogen atoms of the protein and one cadmium ion, but alsosome 49 water molecules. Fourier syntheses using amplitudes of 2F_o-F_c, phase angles prob-abilistically combined from the anomalous scattering and model phase information, witheach term weighted according to its reliability gave clear results without detectable bias to-wards the current model. The final model has acceptable stereochemistry (root mean squaredeviation from ideal bond lengths 0.027 A), and predicts the observed X-ray scattering sat-isfactorily (R = 0.182 for all dat  相似文献   

4.
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.  相似文献   

5.
This paper deals with the effect of amino acid and humic acid on the ion exchange ratio (%)-pHS-shaped curves of the interactions between Cu, Pb, Zn, Cd and clays. The main results are: (i) Withthe increase of concentration of organic matters, S-shaped curve moves first to the left and then to theright, and △pH-(sh(L)) has a linear relationship with log (OB)_m. (ii) With the extent of a certain amountof organic matter, the sequence of △pH-(sh(L)) of heavy metals is Cu Pb Zn Cd, △pH-(sh(L)) has a linearrelationship with IogK_(OA). (iii) With the existence of different amino acids, the relationship between△pH-(sh(L)) of S-shaped curves of interaction between Cu and illite and IogK_(OA) for Cu and various aminoacids are linear. (iv) Quantitative explanations regarding the experimental phenomenon mentioned abovecan be written as the following equation: pH_((CIER))=-1/m{log[(α_1K_(OA)α_2(OB_m))/K_(RB_m)]?2}.(v) Discussion of the phenomenon of left-right shifts of S-shaped curve in terms of reaction mec  相似文献   

6.
游效曾  王曼芳 《结构化学》1989,8(3):212-214
<正> The title compound C18H16FeO (Mr=304. 17) crystallizes in the mono-clinic system,space group P21/c with cell constants a= 14. 428(3),b=9. 939(8),c = 10. 027(5) A .B=93. 73(1),Z=4,Dc=1.41 gcm-3 and V= 1435. 0A 3.The structure is solved by direct methods and refined by least-squares technique to final R=0. 038 and Rw=0.051 based on 2413 independent reflections with I>3o(I). Result shows that both the Cp rings are approximately parallel with dihedral angle of 1. 2 ,The phenyl ring is somewhat tilted from the Cp ring linked to it with a dihedral angle of 8. 36 . The oxygen and carbon atoms of the aceto group are almost co-planar with the phenyl ring.  相似文献   

7.
8.
THE development of the theory of molecular structure and thenature of the chemical bond are discussed.Particular atten-tion is given to the theory of hybrid bond orbitals.  相似文献   

9.
The relative rates of formation of perfluoro iso-propyl radicals (i—C_3F_7,5(i)) and perfluoro n-propyl radicals (n—G_3F_7, 5(n)) are reported. The relative rate constants of β-scission and of bromine abstraction by perfluoro-(α-alkoxyethyl)radicals(RFOCFCF_3:R_F=i—C_3F_7, 3(i); R_F=C_3F_, 3(n)), designated as kr(i) and k,(n), were measured at 7 temperatures in the range of 50—80℃, thence the ratio of the relative rate constants of formation of perfluoro iso-propyl radicals (5(i) and perfluoro n-propyl radicals (5(n)), K_β(i):K_β(n), were obtained. These ratios range from 540—680 at 50℃ to 400—590 at 80℃, much larger than those of the corresponding hydrocarbon radicals. Finally, the differences of activation-free-energy differences between 3(i) and 3 (n), △G~≠(i—n), together with the corresponding enthalpy and entropy terms, △H~≠(i—n), △S~≠(i- n), were calculated. These kinetic parameters indicate that the much higher rate of formation of the perfluoro iso-propyl radicals is caused  相似文献   

10.
THESTUDYOFTHESYNTHESESOFTHEDERIVATIVESOFPOLYPHENYLENEANDTHEIRCONDUCTIVITY¥YinKuiLl;QingZiLIU;SanHUANG;TieFengWEN;ShangYouZHOU...  相似文献   

11.
From the large-scale equations of atmospheric motion, we investigated the long-time behaviour of atmospheric system forcing by exterior steady sources. Firstly, we established the fundamental functional space and operator equations, and then demonstrated the existence and uniqueness theorems of solutions. Based on these results, the existence of the bounded global absorbing set and invariant set in it were discussed. Finally, the nonlinear adjustment process to exterior sources was revealed.  相似文献   

12.
The self-assembly of five narrowly distributed novel rod-coil diblock copolymers, poly(styrene-block-(2, 5-bis[4-methoxy-phenyl]oxycarbonyl) styrene) (PS-b-PMPCS), in p-xylene, a selective solvent at room temperature, was studied. Therod-coil copolymers, which have the same PS length but different PMPCS length, were synthesized by 2,2,6,6-tetramethyl-I-piperidinyloxy (TEMPO) mediated living free radical polymerization. The influence of the rod length on the self-assemblymorphology was studied by transmission electron microscopy (TEM). At a concentration of 2.0 mg/mL, those copolymerswith relatively shorter PMPCS length (copolymers 1 and 2) form individual spherical micelles; those with relatively longerPMPCS length (copolymer 3 and 4) form "pearl chains" coexisting with individual spherical micelles; the ones with longestPMPCS length form "pearl chains" coexisting with occasionally formed nanofibers. The diameter of all the morphologieswas controlled by the rod length. This gives us a way to govern the self-assembly morphology by altering the length of oneblock in the block copolymer.  相似文献   

13.
α-fructofuranosides were stereospecifically synthesized from2-O-Ac-1,3,4,6-O-tetra-benzoylfructose by employing TMSOTf as a catalyst.Meanwhile,one diastereoisomer derivative of sucrose and two of fructanoligomers were synthesized.The structure of all products were confirmed by~(13)C-NMR and ~1H-NMR spectra.  相似文献   

14.
There are two kinds of phycoerythrin of different physical properties in Porphyra yezoensis. Their molecular weights are different. They are both composed of a-subunit and β-subunit. Their polymeric forms are (αβ)n. The absorption bands and fluorescence emission bands of the smaller molecules show hypsochromic shifts of several rims relative to that of the polymeric molecules. The isoelectric point of the former is lower than that of the latter. It is worthy of note that the smaller molecules display binding activities with guinea pig antisera. Through using radioimmunoassay, when the depression of the biuding activity of ~(125)I-insulin reaches 50%, the required quantity of the smaller molecules of R-phycoerythrin would be ca. 0.1mg, corresponding to ca. 8μ units of insulin used in a parallel experiment (26 units corresponding to 1 mg of insulin).  相似文献   

15.
16.
The subject-matter described in the paper reveals the importance of the hydroxyl groups within the molecules of polynitrophenols in the process of the thermal decomposition as studied by XPS (ESCA). It is evident that theintramolecular charge transfer with drastic change during the time of the thermal decomposition can be envisaged as an indicator capable of following the reaction process. The present work shows that combining with CNDO/2 SCF MO model XPS data allow information to be derived reasonably on the relative stability of nitrogen-containing species left in the surface of the energetic materials during decomposition.  相似文献   

17.
Systematic studies on the treatment and reuse of the acid industrial watewater containing sodium 2-Naphthylsulfonate(β-salt)from 2-Naphthanol production process by ND-910 resin (made by self) is reported in this paper.Under the operation conditions of initial β-salt concentration of 10000-25000mg/L and initial CODCr of 20000-40000mg/L,the removal rates of Sodium 2-Naphthylsulfonate and CODCr are over 95% and over 89%,respectively.The effluent can be discharged directly after biological degradation.The working sorption capacity of ND-910 Resin for β-salt is over 230g/kg.An alkali-water wash procedure isutilized to regenerate resin and the reclaiming rate of β-salt is over 98%.  相似文献   

18.
6—O—Mcthylgossypol (3) was obtained with the methods of synthesis for the first time.For the purpose ofe一iminating some prob一ems assoeiatedwith the eliniea一use orgossypol such as irreversibility and hypokalemia,while retaining its pl飞armacologieally desirableantifertility effeets,numerous derivatives and analog  相似文献   

19.
The three dimensional structure of des-pentaptide insulin has been solved at a resolu-tion of 2.4A. The structure determination was achieved without the use of heavy atom de-rivatives, by using only the phase information obtained from the seattering (both real andimaginary) of X-rays by cadmium ions present in the native crystal. Using this phase in-formation, a map, with figure of merit 0.56, was produced which enabled an initial modelof the protein to be constructed. Because of the novelty of this approach to the solutionof the phase problem the procedures used are explained in some detail.  相似文献   

20.
A topological analysis on the ternary 7-phase multisystem involving laihunite (FeO-Fe_2O_3-SiO_2; Q-H-M-W-L-Fa-fs) in P-T plane has resulted in an n+4 phase closed-net-diagram. The most possible straightline-net-diagram was derived by using the thermodynamic properties of the phases concerned. From the straight-line-net-diagram it is apparent that laihunite is not a phase stable only at high pressures. P-T-fo_2, analysis suggests that the formation and stabilization of laihunite are closely related to oxygen fugacity. However, laihunite shows different ways of formation at different pressures. At low pressures, it is formed via the oxidation of fayalite; with increasing pressures the contribution of ferrosilite to the formation of laihunite increases; at very high pressures laihunite can be formed only by the oxidation of ferrosilite.  相似文献   

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