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1.
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   

2.
THESTUDYOFTHESYNTHESESOFTHEDERIVATIVESOFPOLYPHENYLENEANDTHEIRCONDUCTIVITY¥YinKuiLl;QingZiLIU;SanHUANG;TieFengWEN;ShangYouZHOU...  相似文献   

3.
Using the truncated-spectrum model of Burger's-Chao Jiping equation, in which thetemperature advection is involved, we investigated the role of three parameters (Ri number, Renumber, Pr number) in occurrence of turbulence. It is shown that the turbulence may oc-cur only in the case of Ri<0.25 and Rc>2π~2. If Pr is too small (Pr = 0.7 for the atmos-phere), then the turbulence may occur only in the case of introducing interaction betweenbasic field and perturbation field or adding "viscosity" to the model. It is emphasized thatthe temperature advection plays an important role in turbulence occurrence. On the parame-ter plane (Ri, Re), the atmospheric motion states can be divided into the O-region (basicstate), the P-region (periodic state), the T-region (chaotic state), and the T-P region (cha-otic-periodic transition state). In fact, this is appropriate. Finally, the physical reason of turbu-lence occurrence is discussed.  相似文献   

4.
In the presence of Friedel-Crafts catalyst, the chloromethylated copolymer of styrene-divinylben-zene may react with each other and cross-link by itself Thus a new type of polymeric adsorbent wasobtained, and its structure was identified by its physical properties and infrared spectra. The Friedel-Crafts reaction is manifestly affected by the nature of the solvent, the kind and amount of catalystused, reaction temperature and reaction time, etc. The porous structure and physical properties of the adsorbent prepared have been investigatedsystematically. The adsorbent has high specific surface area (1000--1300m~2/g), porosity, narrowpore distribution,high skeleton density and good mechanical properties.  相似文献   

5.
In attempting to study the phototherapeutic action and the photosensitized oxygenation mechanism, we have determined the crystal structure of the main oxidized product of hypocrellin A (HA). It was crystallized in monoclinic system with space group P2_1. The cell data are: a=10.030(3), b=8.877(3), c=15.764(5), β=104.50(2)°, Z=2. The crystal structure has been determined by direct method and refined to a final R of 0.055 based on the 1408 observed reflections with l>2.5σ(Ⅰ). The photooxidized product is composed of a heptacyclic aliphatic hydrocarbon connecting with two α-naphthoquinone derivatives as its skeletal molecule. No peroxidic linkage has been found. On the basis of the crystal structure determined, we have deduced part of the process of formation of the oxide, ⅰ. e. firstly, the peroxide was formed by photocycloaddition of oxygen molecule to Hypocrellin A, then thermodissociation took place to form a stable oxide.  相似文献   

6.
The molecular weight separation and column dispersion for a number of SEC columns packedwith various packing materials were calibrated simultaneously using narrow MWD polystyrene stan-dards as probe. The molecular weight dependence of the spreading factor is closely related to thesurface structure in the pore of packings.  相似文献   

7.
The course of the polypeptide chain of Trichosanthin has been determined from the electron density map at 4 resolution. The structure belongs to α+β type. It contains eight α-helices (39% of total residues) and four β-sheets (32% of total residues) which are made up of thirteen β-strands. The α-helices are relatively in the centre of the molecule and surrounded by β-sheets. This is the characteristic feature of Trichosanthin structure. This kind of structural arrangement has not been reported before. The transformation matrix and translation vector, which superpose two molecules in one asymmetric unit, were obtained. The root mean square error is 1.31 for this superposition.  相似文献   

8.
In this article, on the basis of the characteristics of the moire contour fringes of Nycticebus coucany, Macaca assamensis M'clelland, Presbytis phayrei, Phinopithecus roxellanae, Hylobates concolor leucogenys, Gorilla gorilla. Anthropopithecus troglodytes. Simia satyrus and modern human beings we divide the Primates into two types. The two types of the new classification may be two groups of the evolution moving state.For comparison with each other, the angle γ between the approximately elliptical major axis of the moiré contour fringes on the medial condyle and the horizontal plane is taken as the criterion. We suggest that the Primates evolution to the state of erect walking is the process of the angle γ evolution approaching 90°, regarding the γ of the moire contour fringes of the medial condyle as the evolution angle on the knees of the Primates.  相似文献   

9.
Synthetic type Ib diamonds have been treated in the temperature range of 1500℃—2500℃ under stabilizing pressures of 6.5 GPa and 9.5 GPa. All nitrogen aggregates found in natural type Ia diamonds have been produeed. The single substitutional nitrogen was converted into A-centres, B-centres and N3-centres. The 7,3 μm peak of the infrared absorption spectrum and the associated platelets have been farmed. The synthetic type Ib diamonds have become much harder after heat treatment at above 2000℃ under a stabilizing pressure of about 9.5 GPa. Natural type Ia diamonds have been treated up to 2700℃ under a stabilizing pressure of about 9.5 GPa. The 7.3μm, 7.8μm, 8.5μm, 9.1μm, 9.9μm absorption peaks in infrared absorption spectrum have been changed. A-centres have been converted into B-centres and broken up into single nitrogen atoms, forming N3-centres.  相似文献   

10.
STUDIESONTHECONSTITUENTSOFTHEROOTSOFSCUTELLARIAPLANIPES¥YousYuZHaNG;XianLI;YunZhenGOU(ShenrengPharmaceuticalUniversity,Shenan...  相似文献   

11.
The process of emulsifier-free copolymerization of the Styrene-Butyl Acrylate-K_sS_sO_s-water in thepresence of Barium Sulfate(BS)powder was investigated under varied conditions within the range of BSpowder quantity,initiator concentration and reaction temperature.Experimental results showed thatthe rate of polymerization is proportional to 0.3-power of the BS quantity and 1.3-power of theinitiator concentration.There is a linear relationship of 2/3-power for the conversion and time.Aprocess for the polymerization is propose to explain the experimental results.  相似文献   

12.
Introduction Cholesterol and its close relatives areuniversal components of the ceils of "high-er" organisms, i. e. of animals and plants,the Eucaryotes (which have a cell nucleus).Yet apart from a few instructive excep-tions, Procaryotes, Bacteria and Cyanobacteria(=blue-green Algae), contain no sterols.  相似文献   

13.
A new rhodium(Ⅱ)porphyrin complex was isolated by chromatography from the photochemical reac-tion of(μ—tetraphenylporphyrinato)bis[dicarbonylrhodium(Ⅰ)]with pyridine in benzene and has been charac-terized.From the results,the reaction mechanism is proposed.  相似文献   

14.
A polymer with suitable physical characters and matched functional groups was synthesized,and used as a supporter to immobilize aminoacylase. The results showed that this supporterhad high immobilizing capacity and high selectivity for aminoacylase. Immobilized amino-acylase had high specific activity. In this paper, we determine the physical and chemicalcharacters of aminoacylase for resolution of D,L--phenylalanine, including its optimum tem-perature, pH, ion concentration, activated ion, substrate concentration, thermal stability anddenaturation. The immobilized aminoacylase was used to resolve the D,L-phenylalaninecontinuously. Thc resolved products was separated and purified with ion-exchange resins. L-phenylalanine solution was concentrated by vacuum evaporation and its hydrochloride wasformed. Checking of final product with polarimeter showed high yield and purity.  相似文献   

15.
The temperature of the catalyst bed in the oxidative coupling ofmethane would rise and be higher than the wall temperature when the amountof catalyst, the space velocity and the ratio of oxygen to methane wereincreased. Various aspects of the catalytic technology including the thickness ofthe catalyst bed, the mode of catalyst charge, the ratio of CH_4 to O_2 and thespece velocity were studied. An optimum temperature of the catalyst bed forhigher methane conversion and C_2 selectivity was investigated. It was foundthat the burning of methane in the gas phase to form CO occurred at certaintemperatures with some ratios of oxygen to methane. Additionally, the effectof adding water to the reaction feed gas was studied.  相似文献   

16.
The Lys fragment of mung bean trypsin inhibitor can combine with bovine trypsin to form a complex at an equal molar ratio. The single cxystals of the complex were obtained by using the micro-still-setting method and the X-ray diffraction extended to 1.8 resolution. Its space group is P2_12_12_1 wlth cell dimensions α=62.9(1), b=63.4(1) and c=69.7(2). There is one complex molecule in a crystallographic asymmetric unit.  相似文献   

17.
According to the result of the studies of the Taigu genie male-sterile wheat of the predecessor, a series of inductive inference was made at first. We used the Taigu genic malesterile wheat to make cross with rye to produce polyhaploid plant. By chromosome doubling, the dominant male-sterile gene became homozygous under artificial condition. The result of the experiment obtained shows that the expression and segregation ratio of the stamens of the haploid, amphiploid and the hybrid progenies of amphiploid plants well correspond to the inductive inference, so it confirms once again that a single dominant gene determines the male-sterility of the Taigu genic male-sterile wheat.The authors verify that the Tal gene not only can be expressed normally in common wheat's genetic background, but also can be introduced into the octoploid triticale. The first dominant genic male-sterile octoploid triticale is produced and has been used in triticale breeding program.  相似文献   

18.
THE SYNTHESIS OF INOSOSE¥YiXiang;andJinSHEN(ShanghaiInstituteofOrganicChemistry,ChineseAcademyofSciences,345LingLingto,Shangh...  相似文献   

19.
The polymerization thermokinetics of pyrrole in the presence of iron trichloride art studied by using a Calvet microcalorimoter. The apparent activation energy, the pre-exponential constant and reaction order of this reaction in the temperature range of 25.2—37℃are 34.5 KJ·mol~(-1), 10~(2.74)S~(-1) and 1 respectively. The activation free-energies of this reaction at 25.2°, 30°and 37℃are 91.8, 92.9 and 94.2 KJ·mol~(-1) respectively.  相似文献   

20.
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