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    25 January 1986, Volume 25 Issue 1
    Outline of Spermatophyta Classification
    Zhang Hongta
    1986, 25(1):  1-13. 
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    The ovules of Spermatophytes are derived from the Rhynia-like telome andthe fertil(?)-sporophyll respectively,from them five types of seeds and fruits,i.e.Ginkgoales-type,Cordaites-Bennettites-type,Cycadales-Angiosperm-type,Taxales-Gnetales-type and Coniferae-type are developed.The matured fertilized embryo-sacs of Ginkgo,Cycas,Taxus and Podocarpus are not simple seeds,since thecollar rim of Ginkgo,and the flesh cups of Taxus and Podocarpus are equivalentto the carpels as an effective protect tissue,they are primary types of fruits, which are originated from different ways in the early phylogeny,and differedfrom that of flowering plants;additionally,Gnetum is a well known Chlamvdo-sperm with double-fertilization and without archegonium.Only the Coniferaeis a real representive of Gymnosperm.In this paper,the traditional classification of Spermatophytes is rejected.Allthe Spermatophytes including various Pteridosperm.are divided into the follow-ing subdivisions,they are Pteridospermophytina,Glossopteridophytina,Conifero-phytina,Ginkgoophytina,Cycadophytina,Caytoniophytina,Sinodictiophytina,Taxophytina,Chlamydospermophytina and Phanerogamophytina.To the last sub-division,Phanerogamophytina,a new system is given also.

    Ferromagnetic Phase Transition of the Film and Surface
    Shi Longpei
    1986, 25(1):  29-35. 
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     Ferromagnetic phase transition of the film and surface is studied by the met-hod of Green’s function based upon Heisenberg model with the surface magneticanisotropy.It is proved that the order parameter (spontaneous magnetization)cha-nges with the position in the ferromagnetic film which loses translational invar-iance in one direction.The expressions of Curie temperature and spontaneous mag-netization of each atomic layer in the film have been derived.One expect that theextraordinary phenomena will exist in very thin ferromagnetic film,for instance,as the thickness of film is decreased,Gurie temperature raises,etc.

    Study of Metallic Resonant Grid SMMW Bandpass Filters  
    Zhang Guangzhao; Zhao Jinfu
    1986, 25(1):  36-42. 
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     A series of cross-shaped resonant grids,the resonant wavelengths of whichwere in the region of 55—90 um,have been constructed and the dependence of thespectral characteristics on the grid geometric parameters has been investigatedexperimentally in detail.Two empirical expressions which are useful for desig-ning the resonant grid have been found.Resonant interference filters which co-nsist of two resonant grids have been constructed either.The results show thattheir transmission in the pass-band and the rejection in the rejective-band arevery good and the interference filter is an excellent and practical bandpassSMMW filter.

    Study of Crystallinity of Poly (ethylene terephthalate)——Ⅲ.Melting Point and Heat of Fusion
    Yang Shikun Chen Yujun Pan Jianyuan
    1986, 25(1):  43-49. 
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    Melting point and heat of fusion of PET and its copolymers are studied.Theresults show that:(1)at temperature below its equilibrium melting point,PETmelt can crystallize and form crystals with high melting point.Equilibrium meltingpoint can be measured by relations of T_c and melting points or relations of mel-ting points of copolyesters and percentage of the third component;(2)heat of fu-sion of PET copolymers varys with the molecular structure of additive third com-ponent and its amount.Therfore,Flory’s theory must be corrected,since it didnot take accout of the effect of molecular structure of the third component on themolecular interreaction of polyester.This effect can be characterized by the dif-ferentia of heat of fusion of pure PET and that of copolyester when extraprola-ted to zero fraction of the third component.

    A Principle of Element Dilution(Ⅰ)
    Zhong Guangtao ;Chen Ziang Hong; Jianfong
    1986, 25(1):  50-56. 
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     On the basis of the identical behavior of the elements in the heterogeneouschemical reactions,the present paper proposes the substoichiometric separationelement dilution analysis,derives basic relation formulas which were tested bythe substoichiometric extraction of zin and copper with dithizone in carbon tet-rachloride. 

    The Formation,Development and the Utilization of the Landform of the North of Guongdong
    Liu Shang ren
    1986, 25(1):  57-64. 
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    The macrostructure of the landform of the North of Guangdong appearsas a net pattern.There are basins in the interiors of nets,mountainous regionsin the arrises of nets.The neotectonic movement in this area is chiefly charac-terized by extensive,spasmodic uplift.The uplift may arrive at 700 m or moresince Neogene Period,at 70m since a million years late.The vertical differentialerosion scales in distinct rock stratums and lithologies have arrived at n×100mmagnitudes.The forming of landform of North of Guongdongmainly is not thatmoving tectonics moved differentyl since a million years,but is that was erodedfor a long time on the basis of crustal movement befor a million years.The thesisis yet discussed the relationship between the groups of landform type andconditions of various resources and is raised proposals concerning utilization.

    Positive Solution of Variable Coefficient Semilinear Equation Involving Critical Exponents
    Zhu Xiping
    1986, 25(1):  70-76. 
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     We study the existence of positive solution of variable coefficient equation.We have proved that the equation-(?)=up+λu(p=(n+2)/(n-2),n≥3)exists a positive solution when λ<λ1 and near λ11 is the first eigenvalue of theoperator Lu=-(?).Some existence results of the equation(?)=up+h(x)u are obtained.A problem of [1] is solved and theresults of [1] is deduced as a special case of ours.This work is supported in part by the Foundation of Zhongshan UniversityAdvanced Research Centre.

    The Existence of Limit Cycle of Equations =P(y) =Q(x,y)
    Wang Gaoxiong
    1986, 25(1):  77-83. 
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    For the system of differential equations having the form(?)=P(y),(?)=Q(x,y) (1)R.M.cooper has given in [1] an analytic Criterion for the existence of limitcycle.And a counterexample was given by Wu kiuguang in [2] to show thatcooper’s theorem is not true,He has given some additional conditions to ensurethe existence of limit cycle for system (1),In this paper,some other sufficientconditions on existence of limit cycle for the same system (1) were obtained;besides we show that the additional conditions given by Wu kiuguang can beweakened.Our result generalize the corresponding theorems in [3].

    Asymptotic Method for Nonlinear Systems with Slowly Varying Parameters
    Xu Zhao Cheng Shuili
    1986, 25(1):  84-89. 
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    We generalize the new asymptotic method to nonlinear systems with slowlyvarying parameters.

    Asymptotic Expression and Extrapolation of Tension Spline Collocation for Two-point Boundary Value Problem of Second-order Linear Ordinary Differential Equation
    Han Guoqiang
    1986, 25(1):  90-93. 
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    Tension spline collocation for two-point boundary value problems of second-order linear ordinary differential equation are discussed.Asymptotic expressionsof error are also obtained.By using these asymptotic expressions,Richardsonextrapolation can be done and accuracy of solution can be improved.Numericalresults agree with theory. 

    The Chemical Reduction Behavior of Alkyl Viologens and Polyviologens
    Li Manfu; Liang Zhaoxi; Li Wen
    1986, 25(1):  94-99. 
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     In the presence of sodium dithionite Na2S2O4,the chemical reduction behaviorof alkyl viologens and polyviologens were investigated by means of electrospec-troscopy.It has been found that the chemical reductions proceed in different man-ners according to the structures of viologens.In the case of alkyl viologen,it isrelated to the alkyl chain length n.However,the behavior of polyviologens isquite different from their respective alkyl viologens,only the first step of red-uction can be observed.The intramolecular association of produced polyradicalcations occurs even in dilute aqueous solution

    Superstring Theory
    Li Daxi
    1986, 25(1):  106-122. 
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    Foundamental theories of superstring are introduced.The recent importantprogresses on superstring theories are reviewed.Some interesting directions ofdevelopment of superstring theories are pointed out.