PHYLETIC RELATIONSHIP OF PROTEIN STRUCTURES BASED ON SPATIAL PREFERENCE OF RESIDUES

A distance measure that infers to indicate the evolutionary relationship of protein structures has been developed based on spatial preference factors of residues. The spatial preference factor is a reflection of the environment of residues in tertiary structure. Compared with the phyletic relationships derived from sequence homologies and three-dimensional structures, we find that the two lines of evolution are similar in general. This approach is applied to a group of glins here.     

STUDIES OF HAEMOPOIETIC STEM CELLS AND MICROENVIRONMENT IN CHRONIC IRRADIATED MICE

Mice were irradiated at a dose rate of 70 rad per day for 25 days. Changes in properties and functions of haemopoietic stem cells and microenvironment were observed through a period of 12 months after termination of continuous irradiation. It was shown that the radiation damage of haemopoietic stem cells played an important role in the radiation-induced damage of haemopoiesis. This was further supported by the fact that transplantation of syngeneic bone marrow cells immediately after termination of continuous irradiation at 70 rad per day for 25 days would greatly improve the haemopoietic function of the irradiated mice, including the total recovery of CFU-S and numbers in the bone marrow and cell counts in the peripheral blood.     

EFFECT OF SOLVENT COMPOSITION ON THE SULFONATION DEGREE OF POLY(PHENYLENE OXIDE) (PPO)

This paper investigates the possibility of attaining sulphonated poly(phenylene oxide) (SPPO) with a relativelyhigher sulfonation degree. To achieve this aim, the approach we adopt is to improve the solubility of the final product in themixed solvent so that the sulfonation may take place between the bulk solutions and PPO powders even at higher sulfonationdegree. It is shown that the addition of a proper amount of dimethyl formide (DMF) to the conventional PPO-chloroformsystem can actually enhance the sulfonation effect. The solvent composition is then correlated with the sulfonation degreebased on the solubility parameters. It is interesting to find that solubility parameters between the mixed solvent and theprecipitated products keep an approximately unchanged value at about 4.9, which is just equal to that when pure chloroformis used, though the solubility parameters of both solvents increase with the content of DMF in solution. This may be the mainreason why the addition of DMF can reduce the precipitation and improve the ion exchange capacity (IEC) of SPPOpolymer.     

SYNTHESIS OF ACETIC ACID BY CARBONYLATION OF METHANOL ON Ni(Ⅱ)CATALYSTS

The synthesis of acetic acid by carbonylation of methanol in the presence of Ni(Ⅱ)complexcatalysts at 200℃ under mild pressure was studied.The results showed that among the tested catalyststhe MCC-Ⅰ catalyst had the best performance for the reaction with a mathanol conversion of 98.2%and a carbonyl compound yield of 94.5%.The effects of the pKa values of ligands and the Debyevalues of solvents on the reaction were determined and a suggested mechanism involved in this reactionwas briefly discussed.     

ASSIGNMENT OF ~(13)C NMR SPECTRA OF POLYMER WITH SEMIEMPIRICAL METHOD——SURVEY OF SPECTRUM OF SECONDARY CARBON OF 1, 2-PBD

In chain molecules of 1, 2-PBD, there are two kinds of gauche arrangements, which is the cause of making the spectrum of the secondary carbon in main chain of the polymer split. In such a complex system, the gauche arrangements of the secondary carbon and the tertiary carbon occupy an important position. Hence, the contribution of the tertiary carbon to the chemical shifts of the secondary carbon has a decisive effect on the sequence structure distribution. In comparison the contribution of vinyl groups is much less. The γ values are: γ_1=-6.37～-6.41 ppm represents the effect of the tertiary carbon and γ_2=0.0～-1.56 ppm the contribution of vinyl. The mean square errors are 0.364 and 0.166×10~(-2) ppm~2, respectively in the two cases of considering the effect of vinyl and vice versa. In this paper, we discuss the effects of model chain type, chain length and temperature on the bond probability. Meanwhile, it is pointed out that there exist a few cases, which are not in accord with the usual distrib     

STUDY ON INDUCTION OF DIFFERENTIATION OF A HUMAN MEGAKARYOBLASTIC LEUKEMIA CELL LINE (HIMeg) BY 1,25-DIHYDROXYVITAMIN D_3

It is reported that 1,25-dihydroxyvitamin D_3(1,25(OH)_2D_3), a physiological factor, has aninductive effect on the differentiation of a novel human megakaryoblastic leukemia cell line(HIMeg) in vitro. At the concentrations ranging from 10~(-9) to 10~(-6) mol/L, 1,25(OH)_2D_3 showedinhibition of proliferation on HIMeg cells which was demonstrated by count of survivalcells and cloning efficiency. Meanwhile, using light/electron microscopy, stain of cytochem-istry (including immunoenzymatic technique) and flow cytometry, we found that HIMeg cellscould be further induced into more mature cells in megakaryocytic lineage confirmed by aseries of evidence, including the changes of cell morphology/structure and cytochemistry,increased expression of differentiation antigens on the cell surface, and polyploidization.So, it is possible for 1,25(OH)_2D_3 to promote the differentiation of the cells in megakaryo-cytic lineage in vivo and to be used to treat acute megakaryoblastic leukemia and other di-seases with mal     

STRUCTURE EFFECTS ON THE SOL FRACTION-DOSE RELATIONSHIP IN RADIATION CROSSLINKING OF POLYMERS

The structure effects of polymers on the relationship between sol fraction and radiation dose arediscussed in detail. In consideration of the deviation of experimental results from Charlesby-Pin-ner's and Chen-Liu-Tang's expressions relating sol fraction to radiation dose, we introduced an ex-ponent βconcerned with the structure and property parameters of a polymer (glass transition tem-perature T_g and molecular internal rotating steric factor δ) and assumed that the fracture density isproportional to R~β(R is radiation dose). Thus, a general expression, formula (9), relating solfraction to radiation dose is derived. When β=1 andβ=0.5, this expression is reduced to the above-said two expressions. Us-ing this general expression, the experimental data of a number of polymers are treated. It is shownthat the expression is in good agreement with the experimental results, βvalue is in the range of 0. 5 to1.0.     

MECHANISM OF PHOTOSENSITIZED OXYGENATION OF OLEFINS (Ⅰ) ——QUANTUM CHEMICAL STUDIES OF THE MECHANISM OF 1,2-CYCLOADDITIONS OF SINGLET MOLECULAR OXYGEN TO ELECTRON-RICH OLEFINS

In this paper, we studied in detail the mechanism of 1,2-cycloadditions of the first excited singletoxygen (O_2(~1Δ_g)) to aminoethylene and ethylene by semi-empirical and ab initio calculations ofquantum chemistry. Firstly, the transition states of every elementary process for the above two reac-tion systems were optimized by MINDO/3 attached by Powell method. The results calculated are dif-ferent from those obtained by others. Then we calculated the total reaction paths of the above tworeaction systems using Fukui's IRC theory. The results calculated not only affirm the reliability ofthese transition states calculated by us, but also prove that the reactions of electron-rich olefins withO_2(~1Δ_g) proceed indeed via a zwitterion intermediate. According to these, we explain reasonablythe electronic effects of the substituents.     

THEORY OF UNIFIED REPRESENTATION OF GRAVITATIONAL FIELD

A new theory of gravitational field representation is created to unify the exterior andinterior disturbing fields of the earth by using Newton's potential operator. To do that wego this way: first, we analyze the invertibility of Newton's potential operator and come tothe conclusion that every continuous function belonging to D_g, the orthogonal complement tothe null space of this operator, is harmonic everywhere in the interior earth space; second,we formulate a new kind of boundary value problem of gravics-interior Dirichlet's prob-lem of biharmonic equation with respect to disturbing potential on the supposition that anom-alous mass density of the earth belongs to D_g; then, we simplify the disturbing field intoa quasilinear superposition of two harmonic fields by the aid of the representation theoremson biharmonics proved in this paper. In this way, we finally end up with a unified represen-tation pattern AL of disturbing potential defined throughout the whole space, where L de-notes data performed     

CHARACTERISTICS OF ISOTOPE COMPOSITION OF GASIFORM HYDROCARBON AND IDENTIFICATION OF COAL-TYPE GAS

The natural gas which forms in the course of the formation of coal in the coal-series stra-ta is called the coal-type gas. It is an important genetic type of combustible gas. This papertakes the isotope composition of carbon and hydrogen as a key factor to make an approachto the identification of the coal-type gas and the oil-type gas. According to the isotope com-position of methane carbon and hydrogen, we have divided the natural gases in differentplaces into biogas, coal gas, oil-type gas and coal-type gas. There is a mixed gas area bet-ween the coal-type gas and the oil-type gas. The conditions for the formation of the areaare comparatively complex. The overmature oil-type gas overlies the coal-type gas in distri-bution. According to our studies on oil-gas areas in the Sichuan basin and Eerdos basin,we come to know that the coal-type gas in these basins has an isotope composition of highercarbon. Its mathematic expression of δ~(13)C_1-R_0 is δ~(13)C_1‰ = 8.641 lgR_0-32. 8, representing a mod-el o     

EFFECT OF PELLETING PRESSURES ON GLOBAL REACTION RATES OF METHANOL SYNTHESIS OVER Cu-BASED CATALYST

The catalyst pore structure parameters have a great influence on theintraparticle diffusion which mainly determines the global reaction rates.In thispaper,the effects of pelleting pressures on the global reaction rates were studiedby the chemical reaction engineering theory.As a research system the Cu-basedmethanol synthesis catalysts with different pore structure parameters(specificsurface,pore volume,pore radius distribution,porosity,particle density,tor-tuosity factor etc.)have been prepared by changing the catalyst pelleting pres-sures.Based on the parallel intrinsic reaction rate equations of CO and CO_2 hy-drogenation on C301 Cu-based methanol synthesis catalyst and on the assump-tion that the intrinsic reaction rate constants per unit internal surface are thesame,the diffusion-reaction equations and parallel path cross-linked pore modelwere used for modeling the behavior of the catalyst pellet under industrial con-ditions.The models of global reaction rates had been established for CO andCO_2 hyd     

NONLINEAR GRAVITY INERTIAL WAVE OF TWO DIMENSIONS AND DISCUSSION OF THE POSSIBILITY OF SOLITARY WAVE''''S EXISTENCE

In this paper we discuss the problem of a nonlinear gravity inertial wave of twodimensions and the possibility of solitary wave's existence. First of all, the existingcondition and analytic solution expression of shallow water waves are obtained by theapplication of the qualitative method of O. D. Es. We find that when the problem is de-generated, some physical values produce the nonlinear solitary wave, while other physi-cal values will be unbounded, so we consider that the nonlinear solitary wave for thesystem does not exist. Then we introduce concepts of the generalized energy (i. e. pseu-do-energy): when the pseudo-energy produces the tiny change at acting on a special ex-ternal effect, there will be solitary waves in this system. Finally, we obtain the repre-sentative of the nonlinear solitary wave which is different from KdV equation.     

EFFECT OF CHEMICAL STRUCTURE OF SULFOXIDE GRAFTED POLY (VINYL ALCOHOL) ON GAS PERMEABILITY

The effects of chemical structure, i. e. side chain structure and their contents, on thepermeability of pure SO_2, N_2 and their mixture gases for the sulfoxide grafted poly (vinylalcohol) (RVSO-PVA) membranes have been investigated:where R=Me, Et, Pr, t-Bu and Ph. It was notable that introduction of sulfoxide group intoPVA side chain greatly enhanced the permselectivity of sulfur dioxide. SO_2 permeability andseparation factor of these polymers increased markedly as the size of side chain increased. Thesulfoxide content of the polymer also played an important role in the pure and mixture gasespermeation. Some explanations have been made to interpret this unique gas separation behaviour.     

ANALYSIS OF SYMMETRY OF C_60) ADSORBED ON THE SILVER MIRROR BY SERS SPECTRUM

The SERS spectrum of C_(60) was obtained by using silver mirror. From the SERS spectrum of C_(60) and the IR spectrum of C_(60), we proposed that C_(60) adsorbed on the silver mirror adopts a more ellipsoidal shape.     

DISPERSION STATE OF ZINC OXIDE ON SURFACE OF SILICA GEL AND SURFACE ACIDITY OF ZnO/SiO_2

The dispersion threshold level of zinc oxide on silica gel was determined by X-ray quantitative phase analysis. And the results of XPS experiments show that the surface of the sample is enriched with ZnO and there is a limit for the ZnO amount dispersed on the surface. The value of this limit is corresponding with the threshold level obtained by XRD. The measurements of surfaee acidity show that there are some stronger acid sites on the surface of ZnO/SiO_2, they have not been found on the ZnO or SiO_2 individually, and the total amount of acid increases remarkably. The acidity depends on the ZnO concentration in the surface phase and reaches the maximum at the threshold value.In this paper, we propose a new point of view for the origin of the acidity on surface of the ZnO/SiO_2 samples. ZnO is well dispersed on the surface of SiO_2 gel in a monolayer state. In this situation, some new surface structure units emerge as a result of interaction between dispersed ZnO and the carrier, which are responsible     

DYNAMIC INSTABILITY OF LARGE-SCALE SEA SURFACE TEMPERATURE (SST) DISTURBANCE AND THE FORMATION OF SEA SURFACE TEMPERATURE ANOMALY (SSTA)

This paper proposes that the formation of SSTA is a dynamic instability of large-scaleSST disturbance. Using a linear coupled air-sea model, in which the baroclinic atmosphere isdivided into two levels and the ocean is a mixture layer and a deep water layer, we obtainphysical conditions as well as spatial and temporal seales for the growing of SST disturbance.The major factors for the growing of SST disturbance include Sverdrup transportation, heatexchange between mixture layer and deep water, and modulation effect of clouds on solarradiations. The main horizontal scales of growing SST disturbance range from 3000 to 6000km and its temporal scales are several months. even soveral years. On the basis of thesetheoretical results, the causes for the formation of SSTA are also discussed.     

INFLUENCE OF SOIL MOISTURE AND VEGETATION ON CLIMATE (Ⅰ)——THEORETICAL ANALYSIS TO PERSISTENCE OF SHORT-TERM CLIMATE ANOMALIES

Influence of soil moisture and vegetation on persistence of short-term climate anomalies isanalyzed theoretically through a heat and water balance model in coupled air-land system.It is shown that the soil hydrologic condition, rather than the soil thermal situation, is adominant factor in maintenance of climatic anomalies. The persistence of climate anomaliesis dependent largely on the capacity of water and heat exchange on the land surface. The cli-mate anomalies would persist longer for less soil moisture or vegetation cover. Furthermore,compared with humid areas, the climate anomalies persist longer in an arid climate envi-ronment.     

STUDY OF ACOUSTIC EMISSION DURING NON-ISOTHERMAL CRYSTALLIZATION OF POLYPROPYLENE

In this paper we have presented the results of acoustic emission (AE) during non-isothemal crystallization of polypropylene (PP) melt with mean cooling rate 4℃/min, and discussed the effects of molecular weight (MW) on AE activity. It is shown that the amount of AE ring-down counts during whole crystallization of PP depends on the MW strongly.The copious AE bursts have been observed at the late stage of PPcrystallization. AE bursts are caused by cracking, crazing and cavitation between spherulites and inside spherulites.     

EMPIRICAL RULES FOR ~(31)p-NMR OF ORGANOPHOSPHORUS COMPOUNDS

The substituent effects on ~(31)P-NMR chemical shifts, are determined by five empirical rules. The proposed rules are based on that the shielding (upfield shift) of resonance nucleus is governed by the spherical symmetry of the electron cloud.     

EFFECTS OF La_2O_3 LOADING MANNER ON THE CHEMISORPTION AND HYDROGENATION OF CO ON La_2O_3-PROMOTED Pd/siO_2

The effects of La_2O_3 as a promoter of Pd/SiO_2 catalyst and its loading manner on thechemisorption and hydrogenation of CO have been investigated using in situ FTIR,TPSR,CO adsorp-tion,activity evaluation of methanation and TEM.The results show that the addition of La_2O_3 to thePd/SiO_2 can promote the dissociation and hydrogenation of CO,but causes a noticeable suppression inchemisorption of CO.This is probably due to partially reduced La_2O_3 moieties which decorate the sur-face of Pd particles.In addition,the effects of La_2O_3 promotion on the adsorptive and reactive propertiesof Pd/SiO_2 depend strongly on the loading manner of La_2O_3.It means that the method of preparationhas a significant effect on the degree of interaction between La_2O_3 and the surface of Pd particles.