Abstract: The quality effect of xonotlite-type calcium silicate thermal insulation materials by adding small amount of dicalcium silicate was studied.The basic raw materials were natural powder quartz and nature lime.The experimental result shows that the drying shringage of the themal insulation materials decreases rapidly as the adding amount of C2S increases.When the adding amount of C2S increases from 0 to 5%,the drying shrinkage of the samples decrease from 2.19% to 0.92%,the products become up-to-standard from its originally below the standard.The reason for the decrease of the drying shrinkage is that the adding of C2S promoted the formation of the secondary grains.
Abstract: The electric conducting of polyvinyl chloride composite containing different contents was investigated.The results show that the electric conductivity of the composite is influenced by the length and contents of carbon fibres.Isotropic pitch-based carbon fibres PVC color plastic flour is successfully made,which has a better anti-static electricity and wearability.
Abstract: Under vacuum or vacuum argon blowing conditions,the influences of CaO-BaO-Al2O3-TiO2 and CaO-MgO-Al2O3-SiO2-CaF2 slags on denitrogenation from steel were investigated.It is found that slags decrease the rate of vacuum denitrogenation and vacuum argon blowing decreases the denitrogenation resistance of slags.
Abstract: The effect of trace elements in ZA27 cast alloy,such as Mg,Cu,RE,Ti and thickness of.castings,pouring temperature,modification on the solidification characters of ZA27 cast alloy were studied.The experimental results show that the thickness of castings is the primary factor which affecting the solidification of ZA27 alloy.The solidification characters of ZA27 alloy can be improved by the suitable addition of Ti,and can also be changed with the change of pouring temperature and modification.According to the experimental results,the suitable parameters of technology are recommended.
Abstract: Experimental results of electron-irradiation show that the addition of W and V to the Fe-15Cr-15Mn alloy is effective for void swelling suppression and stability of austenite at grain boundaries increased.Due to addition of W and V,a large of smaller carbides are formed,increasing in quantity of sinks,effectively decreasing the concentration of point defects,simultaneously,the formation of high density dislocation loops is beneficial.Therefore mean free path between dislocation loops decreased.The radiation-induced segregation is remarkably suppressed.
Abstract: The kinetic of oxidation of Ni-Cr low alloying steel under vapour atmosphere is investigated.Several curves is obtained,which indicate that such variables as vapour quantity,temperature and time influence differently on the thickness of oxidation layer on Ni-Cr low alloying steel surface.
Abstract: The microstructure and martensite fraction of 17-7 stainless steels,as cold rolled,tempered 2h at 380℃ and AISI301 stainless steel produced in Franc are examined respectively by magnetization in conjunction with transmission electron microscopy and X-ray techniques.The effect of the cold rolling and tempering on the mechanical properies of AISI301 stainless steel is discussed based on the experimental results.
Abstract: The precipitaion of Al2Ti induced by strain was studied by means of stress-relax method during deformation of Ll2 structure Al3Ti(+9.7Fe) alloy.It is shown that the Al2Ti precipitatings is the principal reason for the ductile fracture of Al3Ti base alloy at room or middle temperature.By TEM,it is proved that the Al2Ti precipitation has rigorous crystal orientation relationship with Al3Ti matrix,{100}p//{100}m.
Abstract: Heavy rail steels,PD2 and PD3,are chosen for the investigation of the impact tougness in as-rolled and reheated state.The results show that the condition of austenite(austenite grain size,homogeneity of chemical contents as well as dissolution and precipitation of carbides),the morphorlogy of pearlite and the interlamellar spacing are the three main structure factors influencing the toughness of pearlite.A basic plan for the toughening of pearlite rail steels is presented,which includes refinement of austenite grain and pearlite interlamellar spacing,homogenization of austenite content and complete dissolution of strong carbide forming elements in the austenite.
Abstract: During hot forming,there are a series of dynamic structure changes in forming metal.These changes have influence on not only the structure,phase transition and quality of product after forming but also the flow stress and forming process.On the basis of taking account of evolution of microstructure effected by forming history and the influence of these changes to forming process,the models to simulate the evoluition of microstructure changes is set up.The simulated results accord with the tested.
Abstract: Based on the principle of knowledge engineering,an intelligent optimization software system IOPS that can be applied to the engineering design is investigated.It is an integrated intelligent program including fourteen kinds of the algorithms for continual,discrete and stochastic variables.This system completes automatic treatment of the symbolic reasoning and numeric calculating in optimization through the concurrent proccessing of the optimization modelling,diagnose of models,selection of algorithm,made decision of multi-objective and valuation of operating parameter etc.expert systems.
Abstract: Based on the analysis of the bridle's mechnical condition,the mechanism of the strip's sliding on the bridle is further explained.The problem of lose of elogation percentage in the tension leveller is analysed.
Abstract: The full integro-differential equation governing the simultaneous conduction and radiation in semitransparent media in the hot-wire experiment is solved numerically.The radiative contribution to the heat flux is analyzed.The effects of medium's absorption coefficient and emissivity on the temperature rise are studied.The effective mean absorption coefficient of medium and the effective emissivity of hot-wire are introduced,and the simplified model is discussed.
Abstract: By applying the direted hypergraph theory,the concepts of the decomposition and contraction of a hyperedge are introduced.Chen's essential complementary partition(ECP)method for solving the cascade problem of two passive networks is improved to form a more efficient decomposition-contraction pair(DCP)method,then it is developed to form the directed(positive-rooted)decomposition-contraction pair(PDCP)method,to solve the cascade problem of two active networks.Furthermore,it is developed to form the general decomposition-contraction(GDC)method,to solve the problem of finding symbolic network functions for the interconnection of several active networks.
Abstract: On the basis of the research and development of general electronic package MC3, "SCR Quasi-witch Model" and "Power Switch Model" are discussed.The simulation of electronic power circuit is performed.
Abstract: On condition of forced convection,the thermal fatigue behaviour of zirconiacorundum-mullite/boron nitride system composites are studied.The activation energy for subcritical crack growth and the stress intensity exponent are calculated.
Abstract: Anomalously fast formation of G.P. zone in Al-Cu alloy could be explained satisfactorily by the mechanism of solute-vacancy complex.It gives more reasonable explanation than the excess vacancy mechanism and the dislocation mechanism do.
Abstract: A ball on disc machine was employed to study the effect of oxidized steel surface on the lubricating performance of sulfurized olefin.Mechanisms of the effect were discussed based on the analysing results obtained with several surface analysing instruments.It is found that better anti-scuffing and antiwear properties could be obtained for the combination of sulfurized olefin and oxidized steel surface.The main reason for the phenomenon can be attributed to the effect of the pretreated oxide film itself and its effect on promoting the formation of chemical reaction film FeS,which results in the formation of a more continuous in structure and thicker boundary lubricating film consisted of FeS and iron oxide on the wear surfaces of oxidized steel.
Abstract: The condition of crack formation in a Fe-25Cr-5Al alloy is investigated by acoustic emission and scanning electron microscopy techniques.The result shows that thermal stress induces to produce microcracks in the alloy.Because of the presence of internal stress and permeation of environmental hydrygen,the longitudinal cracks always occurred,and the failure of the alloy is a process of energy release showing by acoustic emission.
Abstract: Adsorption character and conditions of the five colorants on three different kinds of adsorbent (polycaprolactam powder,active carbon,anion exchange resin)were systematically investigated.Elution behavior of seven inorganic anions was also studied.The results shows that all the three kinds of adsorbent can be used for preseparation of seven inorganic anions in the five synthetic colorants.Recoveries are 95%~105% and matrix interference in ion chromatography is eliminated effectively.
Abstract: AFT algorithm for computing coefficients of Fourier series is given first based on M?bius inversion on Gauss domain.The method used in this paper is available for computing coefficients of wavelet.
Monthly, started in 1955 Supervising institution：Ministry of Education Sponsoring Institution：University of Science and Technology Beijing Editorial office：Editorial Department of Chinese Journal of Engineering Publisher：Science Press Chairperson：Ren-shu Yang Editor-in-Chief：Ai-xiang Wu ISSN 2095-9389CN 2095-9389
