Showing papers by "Wuhan University published in 1985"

Observations on enzymatically isolated, living and fixed embryo sacs in several angiosperm species.

Abstract: A technique has been developed for isolating embryo sacs (ESs) by enzymatic maceration. Ovules were macerated in a mixture of pectinase, cellulase and, in some cases, snailase and pectolyase Y-23. The ovular tissues were removed and the ESs were isolated in toto. Embryo sacs were isolated from both fixed and fresh ovules of Antirrhinum majus L., Helianthus annuus L. and Nicotiana tabacum L. Fluorochromasia by fluorescein diacetate showed that the ESs isolated from fresh ovules were viable. The method has promise for various histochemical and cell-physiological studies and quite possibly also for in-vitro culture of ESs.

On the molecular weight dependence of the second virial coefficient of polystyrene in toluene

Abstract: The molecular weight dependence of the second virial coefficient A2 was measured osmometrically for polystyrene in toluene at 3°C in the molecular weight range of (6.6—445)×103 and compared with the results of our previous light scattering measurements. It was found that for M (molecular weight)>4.5×104, A2osm and A21s agreed fairly well. However for M<3×104 the former was much larger than the latter and followed the relation A2=0.964 M−1/2−4.36×10−3.

New formulations of the second fundamental problem in plane elasticity

Abstract: Some general formulations of the second fundamental problem in plane elasticity are proposed here when the displacements given on the closed boundary contours of a multiconnected elastic region are relative to certain rigid motions which are different to each other for different boundary contours. In such case, it is proved that, for the unique existence of solution, there must be given in addition to the principal vector and the principal moment of the external forces on each boundary contour. A method of solution is given also together with some illustrative examples.

The elimination-compensation-utilization technique of the turbulence effects of the collimated laser beam in the atmospheric propagation--The distribution and compensation of the spot dance

Abstract: when a laser beam passes through the turbulent atmosphere, the main effects which influence the displacement measurement or alignment are the intensity fluctuation, the intensity distribution (speckle), the spot dance and the spot expansion. The effects obey a certain statistical distribution and possess a certain width of probability density distribution curve (spetro-width in brief). And the precision of the displacement measurement or alignment depends upon the spetro-width. Based on the displacement-time converting technique (G.L. Tan J. Optics, Paris, 1981, vol. 12,4) the turbulent influence on the displacement measurement could be replaced by the effects which is of pulse amplitude, pulse shape and the fluctuation of the pulse appearing moment on the time axis. The influence of the photoelectric pulse amplitude and pulse shape on the displacement measurement may be eliminated. (G.L. TAN, ICL Digest, 1983, GUANGZHOU, CHINA). The rest, the fluctuation of the pulse appearing moment on a time axis is just the motion of spot dance of a laser beam passing through the atmosphere. We carried out the experiment to determine the distribution of spot dance, and compared the experimental distribution with that of the ideal distribution. The main conclusion is that the spot dance obeys a normal distribution either in the strong turbulence or in the weak turbulence, whether in the wind rising before or in the wind blowing with the drop in temperature. The maximum deviation of the experimental distribution related to the ideal normal distribution is of -5.5% in the weak turbulence, of 14.2% in the strong turbulence, of 8.4% in the wind rising before and of -18.5% in the degree wind of 4 with the drop in temperature. The probability density distribution curves are shown as in FIG.(1) and FIG.(2).

Studies on titanium organic compounds: VIII. Mechanism of vinyl polymerization in the presence of titanocene dichloride

Abstract: The mechanism of catalytic polymerization of acrylonitrile in the presence of titanocene dichloride under light have been investigated by UV, NMR and ESR spectroscopy. Results of photochemical reaction monitored by UV and NMR showed that titanocene dichloride (Cp2TiCl2) in dimethyl sulfoxide system can be decomposed by light irradiation to give cyclopentadiene. ESR studies show that cyclopentadienyl free radical in photopolymerization system of Cp2TiCl2-acrylonitrile can be trapped by two kinds of spin trapping agents, phenyl-N-tert-butylnitrone and 2-methyl-2-nitrosopropane, respectively. Therefore, the radical mechanism of catalytic polymerization of acrylonitrile in the presence of Cp2TiCl2 under light is further confirmed.

The study on the determination of individual rare earth by rate differential kinetic method

Abstract: Rate differential kinetic analysis offers a simple, rapid and reliable method for simultaneous determination of the mixture of closely related species. It was used to determine individual rare earth elements of 10 −4 −10 −5 M [1,2] . However, the sensitivity and precision are not satisfactory. A new reagent, polyhalogenoarsenazo has been used in this paper in order to enhance the sensitivity. The kinetic behaviours in the reaction of rare earth with polyhalogenoarsenazo have been studied. Some kinetic parameters of the reaction system and the kinetic equation for determination have been measured and established. Individual rare earth elements of 10 −6 −10 −7 M in the Gd-Y, Ho-Er binary mixture and Dy-Ho-Er ternary mixture have been determined simply and rapidly by rate differential kinetic method, the relative errors are generally within 5% for various proportions of the binary mixture.

The determination of γ and ξ parameters in π + →e + e + e - ν decay

Abstract: Possible ways to determine the values of the γ and ξ parameters in π+→e+e+e-ν decay are suggested. We present two kinematic configurations to serve this purpose. The first one is sensitive to γ only, while the second one enables us to determine γ and ξ simultaneously under the assumption that ξ is not unexpectedly large.

Studies on rare earth complexes of crown ether vii complexes of the light rare earth perchlorates with 2,3,11,12 -tetraphenyl-1,4,7,10,13,16,-hexaoxo-2,11-cyclooctadecadiene

Abstract: The previous papers described the synthesis of the first light rare earth nitrate complexes of 2,3,11,12-tetraphenyl-1,4,7,10,13,16-hexaoxo-2, 11-cyclooctadecadiene (L) and the results of their thermal stability were compared with the corresponding complexes of dibenzo-18-crown-6 ether and 18-crown-6 ether [1,2] . In order to deal with the influence of the ligand anion on the properties of complexes, we have recently synthesized five new complexes of the light rare earth (III) Perchlorates with the titled unsaturated crown ether L. These complexes have been identified by elemental analyses, UV, IR and 'H NMR. Their solubilities and molar conductances have also been investigated.

Studies on the coordination compounds of benzo-15-c-5 and 4-nitro-benzo-15-c-5 with rare earths

Abstract: As an extension of our previous studies on the coordination compounds of rare earths with crown ether [1,2] , an investigation has been made by us on the effects of the substitute derivatives of the benzo-15-C-5 (L 1 ) and different anions, which have an influence upon the characterization of the complexes of rare earths with crown ether.