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2004年  第11卷  第6期

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Mineral
Daughter minerals in fluid inclusions of garnet and diopside from Tongguanshan Copper Deposit by SEM/EDS and LRM
Yuling Xie, Jiuhua Xu, Zengqian Hou, Zhusen Yang, Wenyi Xu, Yifeng Meng, Baohua Wang
2004, 11(6): 481-485.
中文摘要(265) PDF(18) SpringerLink
摘要:
Tongguanshan copper deposit of Tongling large ore belt is one of the typical skarn copper deposits. Based on careful observation under microscope many daughter minerals including transparent ones and opaque ones have been distinguished in the fluid inclusions of garnet and diopside. The results of SEM/EDS (scanning electron microscope/energy dispersive spectrometer) and LRM (laser Raman microprobe) analysis show that these daughter minerals in garnet are sylvite, halite, sphalerite, chalcopyrite and carbonate. Sylvite daughter mineral is very popular in garnet and diopside. The existence of so much sylvite daughter mineral and other daughter minerals in the fluid inclusions indicates that the ore-forming fluid is of supper-high salinity and high potassium concentration. High potassium concentration in the fluid inclusions agrees with K-rich mesotype-acid rock and K-silicate alteration that occurred widely in this area. The daughter mineral assemblage in garnet and diopside is similar to the mineral assemblage of oreforming stage that followed skarn stage.
Mineral
Techniques for in-situ stress measurement at great depth
Meifeng Cai
2004, 11(6): 486-488.
中文摘要(254) PDF(10) SpringerLink
摘要:
Reliable information of in-situ stress state is necessary for the design and construction of most important rock projects. As most rock projects are getting deeper and deeper, traditional techniques of in-situ stress measurement are not very suitable. The current techniques of in-situ stress measurement and their insufficiency for use at great depth are analyzed. Some basic ideas of the development of new techniques and the improvement of current techniques for use at great depth are provided.
Mineral
Experimental study of a technique for load measurement of powered supports
Hua Zhu, Shirong Ge, Xiaolong Huang, Sumei Dai
2004, 11(6): 489-493.
中文摘要(254) PDF(8) SpringerLink
摘要:
Despite the increasing popularity of mechanized coal mining, there are no convenient and accurate means available to measure the loads of powered supports. The measurement of such loads is important for monitoring mine pressure and ensuring production safety. The load-carrying features of a powered support were used to develop a method for load measurement using the magnetoelastic principle. A cross bridge-type magnetoelastic stress sensor was designed for the support structures to measure the different parts of the supports. Tests on single-body hydraulic cylinders and simulated linkages showed that an approximately linear relationship between the values of the sensor output signal and the loads borne by the hydraulic cylinders or linkages. The results were used to analyze the load-carrying measurements of powered supports with the cross bridge-type magnetoelastic stress sensor.
Metallurgy
Kinetic study on deep dephosphorization treatment of liquid steel by BaO-based fluxes
Zhihong Tian, Yanyong Guo, Kaike Cai, Liqun Ai, Huien Shi
2004, 11(6): 494-499.
中文摘要(255) PDF(11) SpringerLink
摘要:
Laboratory study was carried out on deep dephosphorization of liquid steel by BaO-based fluxes at 1600℃ to achieve ultra low phosphorus level in the steel. A dynamic model of dephosphorization of liquid steel by BaO-based fluxes was established.According to the model, the controlling step of dephosphorization by BaO-based fluxes was the mass-transfer of phosphorus in steel phase under the condition of low phosphorus liquid steel. It is estimated that the apparent rate constant of dephosphorization by BaObased fluxes was 0.4×10-3-8.2×10-3 g/(cm2.s) and the mass-transfer coefficient of phosphorus in bulk steel was 0.025-0.04 cm/s.
Metallurgy
Thermodynamic study of K2CrO4-KAlO2-KOH-H2O and Na2CrO4-NaAlO2-NaOH-H2O systems
Xidong Wang, Jinlan Cui, Xinlei Ge, Shili Zheng, Mei Zhang, Yi Zhang
2004, 11(6): 500-504.
中文摘要(293) PDF(16) SpringerLink
摘要:
Phase diagrams of complex multi-component aqueous chromium salt system are the important theoretical bases for increasing the recovery ratio of chromium and reducing the poisonous waste in the chromate production process. Phase equilibrium of multi-component system has been calculated from the limited known data with thermodynamic models. The phase equilibriums of KOH-K2CrO4-H2O, KOH-KAlO2-H2O, NaOH-Na2CrO4-H2O and NaOH-NaAlO2-H2O systems were calculated with thermodynamic models. The solubilities of Cr and Al was measured in the systems at different temperatures. The results were compared with experimental data and they are consistent with each other. It shows that the lower concentration of KOH (or NaOH) is favorable for thecrystallization of KAlO2 (or NaAlO2) and higher concentration of KOH (or NaOH) is favorable for the crystallization of K2CrO4(Na2CrO4). Therefore, K2CrO4 (or Na2CrO4) can be separated from KAlO2 (or NaAlO2) with controlling the KOH concentration in solutions of KOH-K2CrO4-KAlO2-H2O or NaOH-Na2CrO4-NaAlO2-H2O systems.
Metallurgy
Mathematical model for the thermal process of controlled cooling of wires and its numerical simulation
Hongxiang Zhu, Xiaohong Hao, Zhi Wen, Yaogen Zhang, Huqiu Chen
2004, 11(6): 505-510.
中文摘要(252) PDF(11) SpringerLink
摘要:
The mathematical model for the thermal process of billets rolling has been established, including transporting in air and temperature-holding cover, descaling with high-pressure water, and the process of rolling and cooling in water box. The calculated data by the model have been compared with the measured data and the results show that the model is right and creditable. Based on the model, the main thermal characters of rolling line have been simulated and the influence of all the parameters on the temperature of rolling has been analyzed.
Materials
Modeling the dendritic evolution and micro-segregation of cast alloy with cellular automaton
Qiang Li, Dianzhong Li, Bainian Qian
2004, 11(6): 511-516.
中文摘要(289) PDF(15) SpringerLink
摘要:
In order to precisely describe the dendritic morphology and micro-segregation during solidification process, a novel continuous model concerning the different physical properties in the solid phase, liquid phase and interface is developed. Coupling the heat and solute diffusion with the transition rules, the dendrite evolution is simulated by cellular automaton method. Then, the solidification microstructure evolution of a small ingot is simulated by using this method. The simulated results indicate that this model can simulate the dendrite growth, show the second dendrite arm and tertiary dendrite arm, and reveal the micro-segregation in the inter-dendritic zones. Furthermore, the columnar-to-equiaxed transition (CET) is predicted.
Materials
Cellular automata modelling of austenite grain coarsening during reheating——I. Normal grain coarsening
Wanhua Yu, E. J. Palmiere, S. P. Banks, Jingtao Han
2004, 11(6): 517-523.
中文摘要(276) PDF(19) SpringerLink
摘要:
A two-dimensional cellular automaton (CA) model has been developed for the description of the normal grain coarsening process. The probabilistic CA method incorporating Moore's definition of the neighbourhood is used to simulate the normal grain coarsening process with a new transition rule. The model simulates the grain coarsening process in as much detail that is possible, from the point of initial nucleation to subsequent coarsening with computational times. The unique result is that the grain coarsening speed can be controlled by the specific method, this result is vital to model the grain coarsening quantitatively. In order to make this model valid, experimental work has been done to provide solid evidence for this model. Comparison of the modelling result and the experimental result has been carried out.
Materials
Microstructure and properties of sputtered thermal barrier coatings
Yang Gao, Lun Xie, Feng Pan, Mengcheng Chen
2004, 11(6): 524-528.
中文摘要(251) PDF(9) SpringerLink
摘要:
A 3 kW radio frequency (RF) magnetron-sputtering unit was used to produce zirconia ceramic coatings on hollow turbine blades and vanes, which had been deposited a NiCrAlY bond coat layer by cathodic arc deposition. The NiCrAlY coating surface was shot-peened, and the residual stress in the bond coat layer and the effects of heat treatment on the residual stress are presented.After shot peening porosities and microgaps disappear in the NiCrAlY bond coat, the whole depth profile is residual compressive stress. Coarseness tests show that the roughness value (Rz) decreases from 16.4 to 3.3 μm. The microstructure and phase composition of the coatings were investigated using electron probe microanalysis (EPMA) and X-ray diffraction (XRD). The results show that the NiCrAlY bond coat is composed of γ' and Cr phases, and the Al2O3 scales are formed near the interface between the ZrO2 ceramic layer and the NiCrAlY bond coat. No degradation occurred to RF sputtered ceramic coatings after oxidating at 1150℃ for 100 h,heating at 1150℃ for 5 min and then air-cooling for 500 thermal cycles.
Materials
Effect of current density on the morphology of Zn electrodeposits
Ailing Fan, Wenhuai Tian, M. Kurosaki
2004, 11(6): 529-532.
中文摘要(199) PDF(8) SpringerLink
摘要:
The effect of current density on the morphology of Zn electrodeposits prepared by a flow-channel cell was investigated by scanning electron microscopy (SEM). It was found that the morphology of Zn electrodeposits evolves from thin-layered hexagonal η-phase crystals to pyramidal η-phase particles with increasing the current density. The morphological evolution at various flow rates was also examined and the results show that the morphological evolution at a lower flow rate is more remarkable than that at a higher flow rate with increasing the current density. To reveal the mechanism of the morphological evolution in detail, the atomic configuration on both (0001)η and {1100}η planes under different current densities was investigated, it was noted that a specify current density could provide a good condition for the layered epitaxial growth of hexagonal η-phase.
Materials
Performance of a combined capacitor based on ultrafine nickel oxide/carbon nanotubes composite electrodes
Xiaofeng Wang, Yanqiu Cao, Yiqiang Lu, Qiqian Sha, Ji Liang
2004, 11(6): 533-538.
中文摘要(324) PDF(9) SpringerLink
摘要:
A new sol-gel process for the preparation of ultrafine nickel hydroxide electrode materials was developed. The composite electrodes consisting of carbon nanotubes and Ni(OH)2 were developed by mixing the hydroxide and carbon nanotubes together in different mass ratios. In order to enhance energy density, a combined type pseudocapacitor/electric double layer capacitor was considered and its electrochemical properties were characterized by cyclic voltammetry and dc charge/discharge test. The combined capacitor shows excellent capacitor behavior with an operating voltage up to 1.6 V in KOH aqueous electrolyte. Stable charge/discharge behaviors were observed with much higher specific capacitance values of 24 F/g compared with that of EDLC (12F/g) by introducing 60% Ni(OH)2 in the anode material. By using the modified anode of a Ni(OH)2/carbon nanotubes composite electrode, the specific capacitance of the cell was less sensitive to discharge current density compared with that of the capacitor employing pure nickel hydroxide as anode. The combined capacitor in this study exhibits high energy density and stable power characteristics.
Materials
Relations of abrasion resistance and hardness of 16Cr-3C white irons with retained austenite content
Zhiping Sun, Rulin Zuo, Cong Li, Baoluo Shen, Shengji Gao, Sijiu Huang
2004, 11(6): 539-544.
中文摘要(239) PDF(8) SpringerLink
摘要:
The relationship between the retained austenite content of the matrix in 16Cr-3C white irons and the abrasion resistance was investigated. The results show that: (1) the abrasion resistance can be improved by sub-critical heat treatment, which could be attributed to the decrease of the retained austenite content; (2) both the abrasion resistance and hardness can be improved by controlling the retained austenite content below 20%-30% and arrive at the maximum when the retained austenite content is reduced to about 10%; (3) the abrasion resistance decreases abruptly once the retained austenite content is lower than 10%, which stems from both the in situ transformation of (Fe, Cr)23C6 to M3C carbides and the formation of pearlitic matrix.
Materials
Dry face milling of titanium alloys
Ahmed Hassan, Zhenqiang Yoo
2004, 11(6): 545-548.
中文摘要(362) PDF(17) SpringerLink
摘要:
In machining titanium alloys, cutting tools generally wear out very rapidly because of the high cutting temperature resulted from the low thermal conductivity and density of the work material. In order to increase the tool life, it is necessary to suppress the cutting heat as much as possible by applying an abundant amount of coolant, but this will entail serious techno-environmental and biological problems. To study the performance and avoid these limitations, a PVD-coated insert was used to the dry face mill of (α +β) titanium alloys. As a result it was found that the inserts exhibit an excellent cutting performance at low cutting speeds and feed rates, and there is no significant difference in the dominant insert failure mode between the wet and dry cutting in discontinuous cutting.
Materials
Dry wear behaviors of wear resistant composite coatings produced by laser cladding
Jiang Xu, Wenjin Liu, Minlin Zhong
2004, 11(6): 549-554.
中文摘要(302) PDF(10) SpringerLink
摘要:
Using different proportional mixtures of Ni-coated MoS2, TiC and pure Ni powders, new typical wear resistant and selflubricant coatings were formed on low carbon steel by laser cladding process. The microstructures and phase composition of the composite coatings were studied by SEM and XRD. The typical microstructure of the composite coating is composed of multisulfide phases including binary element sulfide and ternary element sulfide, γ-Ni, TiC and Mo2C. Wear tests were carried out using an FALEX-6 type pin-on-disc machine. The friction coefficient and mass loss of three kinds of MoS2/TiC/Ni laser clad coatings are lower than those of quenched 45 steel, and the worn surfaces of the laser cladding coatings are very smooth. Because of high hardness combined with low friction, the laser cladding composite coating with a mixture of 70% Ni-coated MoS2, 20%TiC and 10%pure Ni powder presents better wear behaviors than the composite coating with other powder blends. The composition analysis of the worn surface of GCr15 bearing steel shows that the transferred film from the laser cladding coating to the opposite surface of GCr15 beating steel contains an amount of sulfide, which can change the micro-friction mechanism and lead to a reduced friction coefficient.
Materials
Susceptibility of two types of low-alloy hull steels to pit initiation
Jianmin Wang, Xuequn Chen, Guomin Li
2004, 11(6): 555-560.
中文摘要(227) PDF(7) SpringerLink
摘要:
Four low-alloy hull steels with different alloy elements were selected. Their susceptibility to pitting corrosion was compared by means of electrochemical polarization test. The inclusions in the steels and their pitting corrosion characteristics were studied by an electron probe micro-analyzer (EPMA). The results indicate that some inclusions are the main sources of pitting corrosion.The susceptibility of nickel-chromium steel to pit initiation is less than that of manganese steel. Under the same conditions, nickelchromium steel is easier to passivate than manganese steel, and the passive films on nickel-chromium steel surface are more stable than that on manganese steel. In low-alloy steels, the higher the contents of nickel and chromium, the lower the critical passive pH value. In the same kind of steel, multi-phase inclusions containing sulfide are easier to initiate pitting corrosion than other inclusions.
Materials
Pilot biomechanical design of biomaterials for artificial nucleus prosthesis using 3D finite-element modeling
Qijin Huang, Guoquan Liu, Yong Li, Jin Gao, Zhengqiu Gu, Yuanzheng Ma, Haibin Xue
2004, 11(6): 561-565.
中文摘要(410) PDF(11) SpringerLink
摘要:
Pilot biomechanical design of biomaterials for artificial nucleus prosthesis was carried out based on the 3D finite-element method. Two 3D models of lumbar intervertebral disc respectively with a real human nucleus and with the nucleus removed were developed and validated using published experimental and clinical data. Then the models with a stainless steel nucleus prosthesis implanted and with polymer nucleus prostheses of various properties implanted were used for the 3D finite-element biomechanical analysis. All the above simulation and analysis were carried out for the L4/L5 disc under a human worst-daily compression load of 2000 N. The results show that the polymer materials with Young's modulus of elasticity E=0.1-100 MPa and Poisson's ratio v=0.35-0.5 are suitable to produce artificial nucleus prosthesis in view of biomechanical consideration.
Materials
Basic rules for rheologic forging process of semisolid alloy
Shuming Xing, Lizhong Zhang, Jianbo Tan, Chuanlin Zheng, Hanwu Liu, Peng Zhang, Yunhui Du
2004, 11(6): 566-571.
中文摘要(213) PDF(7) SpringerLink
摘要:
Semisolid mold forging is a major type of semisolid processing, which is different from neither traditional mold forging nor traditional permanent casting. However, processing defects are often seen in work pieces because of lacking available rules for the process design and control. Some basic rules for the process design and control, simply named the shortest flowing length, pressure filling and the minimum uplifting mold pressure, are advanced in the paper based on amount of researches and experiments. The equations to determine the major process parameters are given out such as the filling pressure, forming pressure and locking mold pressure for the process design and control. The rules and equations are experimentally proved available and applicable by several actual work pieces produced by the semisolid forging process.
Communication
Research on viral dynamic models of hepatitis B virus infection
Lequan Min, Xisong Dong
2004, 11(6): 572-576.
中文摘要(275) PDF(12) SpringerLink
摘要:
A mathematical model with cytotoxic cells of hepatitis B virus (HBV) infection is set up based on a basic model of virus dynamics without cytotoxic cells and experimental observation of anti-viral drug therapy for HBV infection patients. A quantitative analysis of dynamic behaviors shows that the model has three kinds of equilibrium points, which represent the patient's complete recovery without immune ability, complete recovery with immune ability, and HBV persistent infection at the end of the treatment with drug lamivudine, respectively. Our model may provide possible quantitative interpretations for the treatments of chronic HBV infections with the drug lamivudine, in particularly explain why the plasma virus of Nowak et al.'s patients turnover the original level after stopping the lamivudine treatment.

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