最新刊期
      卷 25 ， 期 1 ， 1986
      • Zhang Hongta
        Vol. 25, Issue 1, Pages: 1-13(1986)
        摘要：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.  
          
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        发布时间：2023-12-08
      • Shi Longpei
        Vol. 25, Issue 1, Pages: 29-35(1986)
        摘要：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.  
          
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        发布时间：2023-12-08
      • Zhang Guangzhao,Zhao Jinfu
        Vol. 25, Issue 1, Pages: 36-42(1986)
        摘要：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.  
          
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        发布时间：2023-12-08
      • Vol. 25, Issue 1, Pages: 43-49(1986)
        摘要：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.  
          
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        发布时间：2023-12-08
      • Zhong Guangtao,Chen Ziang Hong,Jianfong
        Vol. 25, Issue 1, Pages: 50-56(1986)
        摘要：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.  
          
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        发布时间：2023-12-08
      • Liu Shang ren
        Vol. 25, Issue 1, Pages: 57-64(1986)
        摘要：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.  
          
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        发布时间：2023-12-08
      • Zhu Xiping
        Vol. 25, Issue 1, Pages: 70-76(1986)
        摘要：We study the existence of positive solution of variable coefficient equation.We have proved that the equation-（?）=up111p  
          
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      • Wang Gaoxiong
        Vol. 25, Issue 1, Pages: 77-83(1986)
        摘要：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].  
          
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      • Vol. 25, Issue 1, Pages: 84-89(1986)
        摘要：We generalize the new asymptotic method to nonlinear systems with slowlyvarying parameters.  
          
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        发布时间：2023-12-08
      • Han Guoqiang
        Vol. 25, Issue 1, Pages: 90-93(1986)
        摘要：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.  
          
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        发布时间：2023-12-08
      • Li Manfu,Liang Zhaoxi,Li Wen
        Vol. 25, Issue 1, Pages: 94-99(1986)
        摘要：In the presence of sodium dithionite Na224  
          
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      • Li Daxi
        Vol. 25, Issue 1, Pages: 106-122(1986)
        摘要：Foundamental theories of superstring are introduced.The recent importantprogresses on superstring theories are reviewed.Some interesting directions ofdevelopment of superstring theories are pointed out.  
          
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