Abstract: A mechanics-physics model of controlled blast demolition for towery tubular structure is presented, which provides a powerful method to simulate the process of blast demoliton and to design the blast parameter by the means of computer, At the same time, it is verified that the model is valid and the computing method is advanced after analyzing two concrete engineering examples.
Abstract: A new method of collecting dust with NCZ-1 agent separate dust curtain is put forward. The collecting dust mechanism of inertia impaction, interception Brownian diffufrsion and so on is analyzed with the theory of gas-solid two-phase flow. The calculating formula of collection efficiency that suited for this method is put forward based on simulated experiment and former researching achievement of collection efficiency for single collecting dust body.
Abstract: Based on equations of mass conservation, energy conservation and chemical reaction rates, a mathematical model of direct reduction process of carbon-bearing pellets was developed. The calculated results of mathematical model agree with the experimental results. Numerical simulation results are shown as follows:Furnace temperature is the most important factor affecting on the reduction rate of pellets, so that it is necessary to heat carbon-bearing pellets under high furnace temperature. Either for larger pellets or for smaller pellets high metallization can be obtained when the heating time is long enough, although the reduction rate of larger pellets is lower than of smaller pellets during the beginning period. For realizing higher metallization and faster reduction rate, the pellets should contain sufficient carbon.
Abstract: The kinetics of denitrogenization of liquid steel was studied in LEC0436 under 1 600~2 813℃. The results showed that when the temperature is lowen nitrogen removal is controlled by both nitrogen transferring in liquid transfer layer and the chemical reaction at the liquid-gas interfacei and when the temperature is higher, it is only controlled by nitrogen transferring in liquid transfer layer. Under 2 250℃, the effect of temperature on k1' followed Arrhenius formula. The resistance of sulfur on nitrogen removal decreases as the temperature rises, and disappeares at temperature 2250℃.
Abstract: Compared the structure and property of Q235 continuous casting bloom by EPM treating with no-treating after heating working, the influence of structure and prop-erty of heating working with improved and fined casting structure by EPM treating have been researched. The results shown that the structure of heating working by EPM treating is more even, and the crystal is finer than no-treating. The σU increases 6.9%, and αk increases 100%.
Abstract: Optimum researches of cold pressing of Ag-clad Bi-2223 superconducting tapes fabricated by Powder-in-tube method were carried out. Cold pressing was necessary to produce tapes with good texture and high Jc values. The optimum technical parameters are sintering three times at 838℃ for 60h and pressing twice with pressure 2.0GPa and 2.5GPa for the first and second compaction respectively. Reduction rate of cold pressing is 1.5×10-4mm/s. Meanwhile, experimental results exhibited that high density and degree of grain alignment of the tapes are mainly attributed to cold perssing.
Abstract: Ageing process and its hardness change from β to α+Ti2Co of alloy Ti-12Co-5Al were investigated. At 450℃,the amount of transformation increases with ageing time and the boundary between the transformation product and the matrix changes from coherent to incoherent. The maximum hardness is achieved at around 320 minutes. With the same ageing time of 20 minutes, the same thing happens as above with increasing temperatures and the hardness peaks at around 600℃.The addition of element aluminum slows down the kinetics of ageing transformation in addition to its strengthening effect.
Abstract: The heat transfer coefficient at the contacting surface of two specimen was calculated. In laboratory, the temperatures of some points on surface of 1Cr18Ni9Ti were measured under the condition of hot non-deforming press. From these data, the heat trans-fer characters of the speciman were analysed. By finite difference technique, the heat trans-fer coefficient of 1Cr18Ni9Ti stainless steel could be obtained.
Abstract: The inner macrostructures adjacent to the thermocouple node in the samples of cast iron thermal analysis were studied. The experiments indicated that the serious macroporosity, which is around the thermocouple node, often exists in the thermal analysis samples so that the accuracy of Si content predicted by thermal analysis device is reduced. The quartz glass tube and Te content added have no effect on the inner macroporosity, but when the taper of the sample cup is increased, the macroporosity area can rise away from the vicinity of the quartz glass tube and the inner macrostructure near the thermocou-ple node will be sound and homogeneous.
Abstract: The relation between critical pulling velocity and its effect factor is made by heat transport theoretical analyzing of continuous unidirectional solidification. When the distance of spraying position of forced cooling ingot and the liquid-solid interface is shorter than 10 mm.(L ≤ 10 mm),the calculated result of Al and Al-1% Cu alloy continuous unidirectional solidification is approximately identical with experimental result. All of calcu-lated and experimental parameters are quiet matching, and the continuous unidirectional solidification can be stably performed. The way of raising pulling veloc-ity is also mentioned.
Abstract: In order to enhance greatly the strength of steel wires used for suspension bridge, stayed-cable bridge and tyre cord,a new method combining continuous unidirec-tional solidification process with low temperature (under recrystallization temperature) large deformation plastic working is presented for producing super high strength steel wires. The cast iron and stainless steel continuous cast ingots with unidirectional columnar crys-tals have been fabricated successfully. It is confirmed that the continuous unidirectional solidification process can be used for the forming of iron and steel materials.
Abstract: The changes of composition, microstructure and magnetic properties for the samples with composition of Pr17Fe76.5B5Cu1.5 cast alloys after hot-pressing with different strains to be 0%, 30%, 50%and 70% have been studied. As increasing of the strains, Pr and Cu contents of the smples decrease and Fe, B content of the samples increase, however the magnetic anisotropy and magnetic parameters such as μ0Ms,Br,iHc,bHc and (BH)m of the samples enhance. The optimum magnetic properties of Br=1.2 T, iHc=1.22 MA/m and (BH)m=260 kJ/m3 for the samples with hot pressing strains to be more than 80% were obtained, which approaches to the magnetic properties of sintered Pr-Fe-B system magnets.
Abstract: The model of friction moment was set up, for the fist time. The model consider friction moment influence on the stability of rolls, the less friction moment and higher the stability of rolls can be obtained. It is theoretical foundation to set up the opti-mum offset model of rolls.
Abstract: The experimental investigation on the reliability of gear-tooth fatigue strength for through hardening steel 37SiMn2MoV was tested. The tests were carried out on a electro-magnetic resonance fatique test machine of type EMR-1603 (U. K). Four loading sbtrss levels (of 6 samples each) were conducted. Based on the test data, the R-S-N curves and the related equations were fitted. Finally, the limiting bending fatique strength σFlim of the 37SiMn2MoV gear-tooth under different reliabilities have been evaluated.
Abstract: In view of it difficult to adjust the parameters of the industry PID controller and on the basis of analyzing the specific property of neural network, a neural network method is presented, and an adaptive neural network PID controller is designed, The learning mechanic of neural network and the control arithmetic are put foward. It proves the feasibility of the neural network control on line by two examples for the control system on the rolling.
Abstract: A novel speed control system for servo motor was presented. The neuron controller with its self-learning ability and its fast approximate solution algorithm of control sensitivity can realize the on-line learning algorithm. With the neuron controller as the speed controller and the three-phase hysteresis controller as the current controller, the servo system can be made. Through the simulation and the experiment, it shows that the neuron controller has the strong adaptability and better on-line performance.
Abstract: Because of their operational condition, it is difficulty to use sublances to mesure and to conduct dynamic control in the small and medium sized converters. The method of dynamic control over the adaptive static model was presented. Based on the adaptive static final-point control model and the oxygenlance position-charging model, adjust the lance position and other control variables. And then a predication model is started to predict the operational targets and the time for tapping. The results of prac-tical testing have shown that the final-point control model hus good ability to adapt, and accu-racy of the predicted targeting carbon content and temperature by the prediction model reaches 68% and 63% respectively.
Abstract: A Extended Calculus of Constructions(ECC) is introduced. The description of specification for abstract data type with loose semantics and a implementation at the functional language ML are also discussed.
Abstract: The character of optical back reflection and optical transmission through confocal Fabry-perot interferometer is analyzed, and a method of laser ultrasound conjugate detection using interferometer is demonstrated. The experimental results is given. This method can enhance the detection sensitivity of laser ultrasound detection system at least two times.
Abstract: The optimum chromogenic conditions of the colored system that is ternary coordination compound Sc(Ⅲ)-CPA-pc-Ⅰ- and its main characters were studied systemati-cally. The influence of some foreign ions on this colored system was measured. Beer's law is obeyed over a range of 0~7.5 μg Sc/25ml. The relative molar absorpbility is 1.4×105 1·mol-1·cm-1. The system was used to determine the trace amount of scan-dium in a synthetic sample and in Pan Zhihua magnetite, the results were satisfied.
Abstract: Applying the Bayesian analysis,utilizing fully the historical information, got the optimum parameters estimations was got, thus established the control charts and the cause selecting control charts and the diagnosis theory with two kinds of quality for small volume.Practical case studies proved that the theory is in accordance with the practice.
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
