Abstract: During heating to certain temperature region, kyanite can transform to mullite, which possess good properties at high temperature, and free SiO2 formed. As temperature increases, the kyanite expands and its volume wight decrease. At room temperature, clay is plastic, but it can contract and transform to refractory at high temperature. The plastic refractory materials made from kyanite, clay, some additives and other compounds. It possess following propeties. plasticity at room temperature, slight exponsion at high temperature, resistance to thermal shocks, high compressive strenght and tensile strenght.
Abstract: The analysis of the mass and enthalpy balances is made for the smelting reduction process in the two-stage of shaft furnace-iron bath. Because of the relevance to carbonaceous as well as hydrogenaceous gases in the process, the Fe-C-O-H2 system is employed. The two combining equations of the oxygen balance and the enthalpy balance for prereduction and smelting reduction reactors are formulated respectively- Two equations can be related reasonably by means of calculating thermodynamic results and the Rist diagram of the process is figured out. The mathematical model is developed for calculating the fuel rate, oxygen consumed and other control parameters for the process.
Abstract: According to the coexistence theory of slag structure, phasediagram Na2O-SiO2 and the corresponding thermodynamic data, a calculating model of mass action concentrations for the slag system has been deduced. The calculated NNa2O and NsiO2 by this model are in good agreement with measured aNa2o and asio2 from literature source respectively. Thus it shows that the coexistence theory of slag structure is applicable to slag system Na2O-SiO2 too.
Abstract: In this paper, two different sizes of high-speed-steel powders have been mixed and then consolidated dynamically by means of a cylinderical converging explosive method with a ring-shape flyer. It has been found that the behaviors of large powder particles differ from that of small powder partieles. After the passage of shock-wave the energy absorption on small powder particles is much greater than that on large powder particles, so that the small power particles may melt prior to large powder particles.
Abstract: The coating on the clour sheet can be formed faster and better at normal temperature by means of the pre-treatment technology. This technology has extensive suitability ani can conserve energy consumption. The relation between the composition of the pre-treatment solution and the effect structure on the performance of the colour coated sheet are also discussed.
Abstract: A efficient thermal conductivity concept has been developed in several problems involving thermal conductivity varying with temperature, two-layer complex plate and anisotropic material. According to a principle in which the heat flux of these plates must be equal to that of a homogeneous isolropic constant thermal conductivity plate, the expression of these efficient thermal conductivities have derived and their applied conditions are also pointed out.
Abstract: On a computer simulating compensation of the transmission error, the time and precision of the calculating forecast error of the time-invarying parameter model is compared with the those of the time-varying parameter model. It is indicated that the transmission error forecast model must be time-varying parameter model. Some methods are proposed in order to heighten forecast speed of the time-varying parameter model and realize the error compensation and control. The results are significalive of actuality to compensation and control of the transmission error.
Abstract: Using the method of Modified Fast Fourier Transform and of least square, the periodical variation signal is produced by the eccentricity in a cold mill is detected. By means of this signal detected, the system of roll mill press down is controlled to compense the thickness variation of the strip. Finally a way of periodical correction is presented to avoid the accumulation of errors appeared in the phase computation.
Abstract: Based on pole assignment, a simple self-tuning control algorithm with PID structure is proposed. This algoritim is simple in structure, easy realized, robust and also applicable to non-minimum phase system. Moreover, this algorithm has found application in controlling a group of cover annealing furnaces with microcomputer in an iron and steel company. Real-time control result shows that the proposed algorithm has good steady-state regulating and tracking properties, and control performance is much better than that of the traditional instrumental PID regulator. It is also applicable to other slowly varing systems.
Abstract: No experimental therniodynamic properties of Ge-Si system have been reported in literature. But the phase diagram has been measured exactly many times. In this paper the thermody namic properties of Ge-Si system have been calculated from phase diagram by using computer program CABPD (Calculating Activities from Binary Phase Diagrams) presented by the author in a previous paper. The excess free energies in liquid and solid solution can be expressed as: EGm(L)=7125XSiXGe(J/mol) EGm(S)=4808XSiXGe(J/mol) and the activities of Ge and Si in liquid and solid solution have been also given. They show positive deviations from Raoult's law.
Abstract: The deposition ratd and microhardnoss of the coating ofTiC and TiCxNy increase with input molar ratio (mc/Ti) and the maximum microhardness of TiC and TiCxNy are achieved as the ratio is 1 and 0.87 respectively. The coalings identified by X-ray di ff ractometer is TiC and TiCxNy. When m=0.94-1.47. deposition temperature at 1 223-1 323 K. the η phase at interlayer between the substrate and TiC coaling is not formed; mc/Ti=0.68-1.54. at 1 248K, N2/H2=1/2. the coating only is TiCxNy; mc/Ti ≤ 0.28. the η phase is formed. The apparent activation energy of TiC is 157.9 kJ/mol. It proves that the deposition process is controlled by surface process.
Abstract: This report described a study on polarization behaviour and AC impedance character of pure nidkel in neutral solution of H3BO3-Na2B4O7 and in redox solution of H3BO3-Na2B4O7 + K3Fe (CN)6/K4Fe(CN)6 by means of polarization curve and impedance techniques. The electrode reaction and electro-model of passive film are also discussed.
Abstract: In this paper, another new sensitized colored multicomponent coordination compound in the system of "Chromium(Ⅲ)——Eriochrome cyanineR——Alkyl dimethy laminoacelic acid" has been developed. The optimum conditions for the formation of the coordination compound in this system have been studied. It will not be decomposed by various masking agents such as EDTA, CyDTA, citric acid, tartaric acid etc; while in that case, almost all the colored coordination compounds formed by other ions will be decomposecompletely. This inert character of this multicomponent coordination compound and its utilization in improving the analytical selectivity have been discussed. In the coexistence of various foreign ions, the direct determination of chromium has shown a satisfactory reproducibility. It was also proved as our former report that the sensitizer cetyl dimethylaminoacetic acid(CDMAA) or tetradecyl dimethylaminoacetic acid(TDMAA) is more suitable to be used in the spectro-photometric determination of microamount of chromium with high sensitivity. When CDMAA and TDMAA are used as sensitizer in this system, the molar absorptivity are 1.14×105 and 1.22×105 respectively. From the results of determination in some synthetic and actual samples, it showed feasible to use this system in the determination of low chromium in steels and microamount of chromium in the waste water from elctroplating or other industries.
Abstract: In this paper, based on the feature of crystal sites occupied by alloying elements, a model cluster, investigating the interacting mechanisms of nonmagnetic element Cu in RECo5 type alloy, has been presented. The electronic structure has been calculated with SCF-X-SW method. The calculating results show that, after Cu replaces 2c crystal site Co, the energy spectrum of the model cluster will move towards shallow well potential, energy gap will become small, the charge a momg the atoms will be redistributed, and some new stales to which impurity contributes will be produced; Partial-wave local density of slates gave interactions between atoms. Results of Hellmman-Feynman force show that thermal expansion anisotropy of the model cluster will be decreased considerably after Cu insteads of 2c crystal site Co.
Abstract: A new algorithm which is called the Up-down Algorithm, forsolving a global optimization problem is given. The algorilhm is more efficient for a class of engineering optimization problems that have a dimension n ≤ 5-6. The algorithm and its convergence, optimization condition, some suggestions about the computation, and the examples are given.
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
