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1998年  第5卷  第2期

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Mineral
Economic-Mathematical Method to Determine the Optimum Production in Underground Coal Mine
Shaowen Zhang, Xiangyi Li, Zhongxui Li, Guangcheng Wang
1998, 5(2): 57-60.
中文摘要(253) PDF(8) SpringerLink
摘要:
A method to determine optimum production is presented. First, based on analysis of various geological, technological and economic factors that influence the determination of underground mine capacity, a feasible range of production capacity is selected. Second, by means of scale economic theory and depletion feature of mineral resounce, an economicmathematical model that aimed at maximum net profit in the whole life of mine is developed to optimum production. The model was tested in a undergrond mine.
Metallurgy
Investigation on Coal-Oxygen Scrap Melting Process
Rong Xhu, Yanhui Sun, Yongquan Qiu
1998, 5(2): 61-64.
中文摘要(205) PDF(10) SpringerLink
摘要:
Investigation on the coal-oxygen scrap melting process shows that using internal-combustion coal-oxygen burner to melt scrap is feasible. Among four types of coal-oxygen furnaces-oxygen burner melting furnace is better than other types on the quotas of process. The metal yield is 95%~97%, the melt down carbon and sulphur contents are >1.0% and <0.080% respectively for this melting furnace. The coal-oxygen scrap melting process would have a significant effect on the technological transformation of EAF and BOF in China.
Metallurgy
NOx Formation from Several Chinese Coals during Combustion in Packed Bed
Shengli Wu, Chunbao Xu, Qiushuang Shou, Daqiang Cang
1998, 5(2): 65-69.
中文摘要(219) PDF(8) SpringerLink
摘要:
The formation characteristics of NOx during combustion of four typical Chinese coals have been studied in a packed bed combustor. The studies included the effects of chemical composition of coals and volatile matters, and combustion conditions, i.e. preheating temperatures of combustion gas, on conversion of NOx during combustion. In term of the combustion experiments, there is a close relation between coal composition and conversions of NOx. Coals with a higher nitrogen content give a lower FNOx0, and coals with a higher volatile content give a lower FNOx0. The further devolatilization experiments showed that volatile matters in the coal have an important effect on reducing conversion of coal-nitrogen to NOx. It was interpreted as that the release of volatile matters during combustion caused a fuel-rich circumstance in the vicinity of coal particles which may restrain the formation of NOx. Preheating temperatures of combustion gas has significant effects on conversions of NOx and there exist a critical preheating temperature. At such temperature, lower FNOx0 can be reached.
Simulation and Optimized Design of Grid Concentration Transducer for Two-Phase Flow
Chen Xianzhong, Cang Daqiang
1998, 5(2): 69-69.
中文摘要(294) PDF(8) SpringerLink
摘要:
A new concentration transducer for the measurement of gas/solid two-phase flow in the profile of pipeline was studied. The design of grid electrode was employed, and hence the distribute of electric field in the space was homogeneous effectively. The variance of measurement value for the influence of flow regime variations has greatly reduced, and the precision of measurement was improved. Meanwhile, optimization of axial property in the grid electrode increases the ability of tracing and measuring of the concentration signal in real-time.
Mechanism of Increase in Strength of Sodium Silicate-bonded Sand by Silica Sand Surface Modified in High Temperature.
Zhu Yulong, Cai Zhensheng, Hu Hanqi
1998, 5(2): 69-69.
中文摘要(257) PDF(13) SpringerLink
摘要:
With the aid of XRD, SEM and EDS etc., there is absorbed film on sand grain surface, high temperature modify makes the film sintered firmly on sand grain surface. Thus it changes physical and chemical characteristics of the film and sand grain surface, improves the wetting properties greatly, makes the fracture features of bonding bridge change from the adhesive to the cohesive and raises the strength of sodium silicate-bonded sand.
Metallurgy
Restraining NOx Formation during Coal Combustion in Packed Bed
Shengli Wu, Chunbao Xu, Qiushuang Shou, Daqiang Cang
1998, 5(2): 70-74.
中文摘要(200) PDF(7) SpringerLink
摘要:
The effects of various combustion conditions (i.e. particle size of coals, oxygen concentration in combustion gas and coal content in the fuel bed, etc.), on reducing conversion of NOx during coal combustion were studied. Under the present combustion conditions, coals with smaller particle size gave the lower conversion of NOx, and as expected that an decrease in overall stoichiometric ratio, whether by an decrease in O2 content in combustion gas or by an increase in coal content in fuel bed would lead to a lower conversion of NOx. In order to investigate the effect of metallic oxide layers on restraining NOx formation, the combustion experiments for coal granules with adhering layer of various metallic oxides including Fe2O3, Ni2O3 and mixed oxides Fe-Ni-Ox were conducted in a packed bed combustor. The combustion experiments have shown that most of adhering materials gave considerable effect on reduction of NOx emission during coal combustion.
Metallurgy
Kinetics of Carbide Layer Forming on the Surface of Steel in Molten Systems
Shuhuan Wang, Shengwen Wu, Shantong Jin
1998, 5(2): 75-79.
中文摘要(247) PDF(8) SpringerLink
摘要:
A mathematical model of kinetics of carbide layer formed on the surface of steel in fused system was set up with the theory of non-stable diffusion mass transfer and regular solution sub-lattice. This model was analyzed and testified by the experiments in which the VC layers were formed on four kinds of steels as steel 45,4Cr5MoSiV1,T10, and Cr12MoV immersed in the V2O5-Na2O-B2O5 fused system with the reducing agent of silicon.The results showed that there was a good agreement between the model and the experimental results;the growth speed of carbide layer depended on the factors of carbon activity in substrate, treatment temperature,kinds of carbides and its structure etc.
Metallurgy
Denitrogenization from Liquid Steel by Fluxes Treatment
Wenzhuo Guo, Shantong Jin, Xinhua Wang, Jun Shu
1998, 5(2): 80-83.
中文摘要(227) PDF(12) SpringerLink
摘要:
By measuring the solubility of nitrogen in BaO-contained and TiO2-contained fluxes at 1623K, the nitride capacity and nitrogen distribution ratio were calculated. Both fluxes had high nitride capacity and nitrogen distribution ratio. The results indicated that Both fluxes treatment were available for denitrogenizing steel. The kinetic studies about denitrogenization showed that nitrogen transfer in liquid steel is the controlled step of denitrogenization reaction, so to improve the mass transfer condition in liquid steel could accelerate the rate of denitrogenization. Under proper test conditions, it was proved to be possible to remove nitrogen over 70 percent from steel with TiO2 contained fluxes.
Metallurgy
Some Concepts on Statistical Models of Relating Mechanical Properties to Chemical Composition
Jun Wu, Chaobin Hao, Yana Wang, Shiqi Li, Linjie Yang
1998, 5(2): 84-86.
中文摘要(224) PDF(7) SpringerLink
摘要:
Following the basic principle of modem multivariate statistical analysis theory, the description model, prediction model and control model to relate chemical compositions and mechanical properties of steels are introduced. As an example, the total flowchart of components and structure/properties description, prediction and control model for chemical composition and mechanical properties of 20 and A3 steel are presented.
Metallurgy
Aluminum Control in CrNiMoV Steel during Electroslag Remelting Process
Anren Wang, Yueguang Yu, Jie Fu
1998, 5(2): 87-89.
中文摘要(273) PDF(11) SpringerLink
摘要:
The residual aluminum content has a great influence upon CrNiMoV steel properties and the optimal content is about 0.010%. The aluminum control during the ESR process has been investigated in this paper. All experiments were car ried out in a 20 kg ESR furnace. The results show that when a 60%CaF2-30%Al2O3-5%SiO2-5%CaO slag system and proper deoxidizing schedule is used, a reasonable ingot with optimal aluminum contents can be obtained. Silicon and magnesium contents are approximately the same with those in the electrode.
Materials
Thermochemical Evaluation of Combustion Synthesis of Al2O3/B4C Composite
Yonghe Liu, Sheng Yin, Weijing Zhang, Hoyi Lai
1998, 5(2): 90-92.
中文摘要(254) PDF(12) SpringerLink
摘要:
The equilibrium phase and adiabatic temperature for combustion synthesis of Al2O3/B4C employing Al, B2O3 and C as starting materials is analyzed by both conventional and CALPHAD method. The adiabatic temperature calculed by CALPHAD method is significantly lower than that obtained by conventional method. The CALPHAD calculation also reveals that the equilibrium phases presented at the adiabatic temperature are different to the desired composites. The adiabatic temperature in this system can be lowered by introducing Al2O3 as diluents. The maximum amount of Al2O3 that can be added to the system while maintain a self-sustaining combusion mode is 1.3 mol.
Materials
Copper Elimination from the Molten Steel by Addition of Hydronitrogens
Liansheng Li, Changxiang Xiang, Jie Cao, Shiqi Ii, Eiji Ichise
1998, 5(2): 93-96.
中文摘要(282) PDF(10) SpringerLink
摘要:
A novel method has been proposed to remove copper from molten steel by adding the compounds of hydrogen and nitrogen into the melt at normal pressure. Feasibility experiments were carried out in Mo-wire resistance furnace at 1600℃. The copper content of about 400 g 45 steel were reduced from 0.60% and 0.57% to 0.41% and 0.51% with 3.25g and 1.20 g NH4Cl respectively, while the copper contents of about 300 g steel melt were reduced from 1.15% and 0.61% to 0.90% and 0.56% with 4.10 g and 2.00 g NH2CONH2. These results indicate that the proposed method is very promising to be put into practical and worthwhile of further study.
Materials
Nitrogenation Process of Nd(Fe, Mo)12 Compound
Qi Zeng, Yiaofu Xiao, Yunshen Deng, Xubo Liu, Shenzhi Dong
1998, 5(2): 97-99.
中文摘要(196) PDF(7) SpringerLink
摘要:
The reaction kinetics between nitrogen gas and Nd(Fe, Mo)12 intermetallic compound has been studied. The relationship between the reaction temperature, the reaction time with average mass fraction of N in samples have been measured. The activation energy of first step reaction, Ef,(18.2 kJ/mol), is smaller than Es (64.6 kJ/mol) of the second step during which nitrogen diffusion in the range 400~550℃ can be represented by an activated interstitial diffusion process. Heating above 550℃ leads to disproportion of the compound into NdN and α-Fe and the permanent properties will be damaged greatly.
Intelligent Control of Multi-fingered Robot Hand
Yuan Kui, Yu Che, Guo Feng, Yuan Xingjun
1998, 5(2): 99-99.
中文摘要(328) PDF(7) SpringerLink
摘要:
The dynamics properties of a kind of multi-fingered robot hand is analyzed. It is pointed out that the dynamics property of this kind of multifingered robot hand in the approaching process is quite different from that in the grasping process and,different control algorithm should be taken in the two process. A position-force hybrid control algorithm is proposed which is applied to the control system of the University of Science and Technology Beijing double-thumb robot hand successfully.
Behavior of Inclusions in Steel 16MnR
Zhang Xuehui, Han Yuwen, Cai Kaike, Xiao Zhongmin, Meng Fanqing
1998, 5(2): 99-99.
中文摘要(273) PDF(10) SpringerLink
摘要:
The regularity of the development of inclusions and the cleanliness level of the steel 16MnR during the whole process are investigated. The emphasis is focused on the type, quantity, distribution, sources and formation of the large oxide inclusions in ingot. The result shows that the major inclusions in ingot are block Al2O3. The large oxide inclusions mainly come from entrapment of complex slags.
Materials
TEM Study of Microcrack Nucleation and Propagation for 310 Stainless Steel
Hongqi Li, Qizhi Chen, Yizhong Huang, Yanbin Wang, Wuyang Chu
1998, 5(2): 100-103.
中文摘要(264) PDF(12) SpringerLink
摘要:
TEM in situ tensile tests of 310 stainless steel show that a dislocation free zone (DFZ) forms if the displacement keeps constant after dislocations are emitted from a crack tip. The elastic DFZ is gradually thinned and the stress in the DFZ will reach the cohesive strength, resulting in nucleation of nanocracks in it and their bluntness into voids. If continuously tensioning, the inhomogeneously thinning ahead of the crack tip, initiating and connecting of microcracks or microvoids will be observed rather than a DFZ, nanocracks' initiation and bluntness into voids. The inverse pile-up ahead of a loaded crack tip can move back to the crack tip when unloading.
Automation
Autonomous Path Planning For Robot Manipulators in Manufacturing Environment
Wei Wang, Yang Yang, Kui Yuan
1998, 5(2): 104-107.
中文摘要(323) PDF(9) SpringerLink
摘要:
A robot intelligent path planning system(RIPPS), which can be used as a robot off-line programming tool was introduced in this paper. C-space modeling and path search are key parts of the system. A fast C-space modeling is presented based on critical collision joint angle(CCJA), C-obstacle boundary can be computed by the feature points of obstacles. A modified A* algorithm is used for path search, although the path is slightly sub-optimal, a tremendous speed increase is achieved. RIPPS runs on a Silicon Graphic 4D/70 workstation, simulation results show that the system is efficient and practical for robot collision-free autonomous path planning in a structured and known environment.
Automation
AGC-ASC Synthetic Neural Net Control System in Rolling Process
Zhongsuo Shi, Yuan Li, Yikang Sun
1998, 5(2): 108-112.
中文摘要(255) PDF(7) SpringerLink
摘要:
Automation Gauge Control(AGC) and Automatic Shape Control(ASC) are coupling each other. The coupling models of AGC-ASC synthetic system for the thickness-crown have been established and two artificial neural networks controllers are given. The simulation of computer shows that the AGC-ASC synthetic system can obtain the expected thickness and shape precision with both schemes.
Brief Report
Processing HREM Image of Mn-Al Icosahedral Quasicrystal
Lequan Min, Xiaodan Zhang
1998, 5(2): 113-114.
中文摘要(171) PDF(7) SpringerLink
摘要:

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