2025-04-09 2000, Volume 7 Issue 2

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  • Zhi-you Li , Bai-yun Huang , Yong-li Zhu , Zhi-jian Liu , Xuan-hui Qu

    Three kinds of lithium-cobalt oxides with lithium to cobalt atomic ratios of 0.6, 0.8 and 1.0 respectively were prepared using nitrates and citric acid by sol-gel process. During the baking of the dry-gel powder, two exothermic peaks occur, followed by the formation of Li2O and Co3O4 and then the combination of LiCoO2, which is testified by DTA and XRD. The powder formed from an alkaline sol is finer than that from the acidic one. There are a single phase intercalation of lithium ion and an electrochemical reduction reaction for higher-valence cobalt ion when simulating the discharging process of Li-B/LiCl-KCl/lithium-cobalt oxides at 500 °C, and the voltage and specific capacity are not sensitive to the initial ratios of lithium to cobalt.

  • Hao-ran Gong , Wen-xian Li

    Heat treatment of spray deposition 10% SiCp/6066 (ϕ(SiCp) = 10%) composites was investigated by means of hardness measurement. The results show that heat treatment technology is influenced by the presence of SiC particles. Compared with the base alloy 6066, the composites have lower burning temperature and is burnt at 540 °C due to the enrichment of Mg and Cu atoms in the SiCp/6066 interfaces. As a result, solution treatment of the composites should be carried out at lower temperature. The aging parameter values such as the aging temperature, the precipitation temperature of β′ and β phases, as well as the peak aging time, become lower. The optimum heat treatment process conditions are that the composites are solution-treated at 515 °C and aged at 165 °C for 5 h.

  • Cheng-yu Tan , Zi-qiao Zheng , Chang-qing Xia , Ying Liang

    The aging behaviors of Al-1.42% Li-2.41% Cu-0.93% Mg-0.073% Zr-0.17% Sc (mass fraction, the same below) alloy at room temperature, 160 °C, and 160°C after 8% pre-deformation were studied respectively by hardness measurement. The microstructure of the alloy in various aging conditions was observed by TEM. The results show that the main precipitations of the alloy in quenching condition are the particles containing Sc and Zr which have certain coherent relation with the matrix. Addition of Sc in Al-Li-Cu-Mg-Zr alloy will be favorable to promoting precipitation. The particles can serve as preferred nucleation sites for δ′ phases which accelerate the aging hardening rate at initial aging. The main hardening phases of the alloy aged at 160 °C are δ′ and δ′/β′ composite precipitates. The size of the composite precipitates is very small (nanometer size). The composite precipitates will preclude efficiently the formation concentrative slip location and will improve the mechanical properties of the alloy. S′ phase will occur in the alloy aged at 160 °C after 8% pre-deformation. It is found that 8% pre-deformation has no obvious influence on the precipitation of the composite phase.

  • De-qing Zhu , Guan-zhou Qiu , Tao Jiang , Jin-chang Xu

    Successfully developed an innovative process of direct reduction of cold-bound pellets from iron ore concentrate with a coal-based rotary kiln, in comparison with the traditional direct reduction of fired oxide pellets in coal-based rotary kilns, possesses such advantages as: shorter flowsheet, lower capital investment, greater economic profit, good quality of direct reduced iron. The key technologies, such as the composite binder and corresponding feasible techniques were employed in practice. A mill utilizing this process and with an annual capacity of 50 thousand ton DRI has been put into operation.

  • Guang-ming Song , Xiu-zhi Shi , Zhi-guo Zhou , Shou-ru Chen , Qing-hua Xiao

    A type of velocity sensor CD-1, an auto-recording instrument on blasting vibration YBJ-1 and a random signal and vibration analysis system (CRAS) were used to monitor the particle vibration induced by blasting at open-pit slope in Hainan Iron Mine. The attenuating rules of blasting ground vibration on slope were developed. By means of the analysis and calculation of the blasting vibration data at open-pit slope and the vertical particle vibration velocity assessment method based on the concept of vibration strength, the empirical attenuating equations which can be used for predicting and estimating the damage of slope were derived.

  • Li Gu , Ta-gen Dai , Cai-hua Deng , Wei-ming Fan

    Based on the data from typical core sampling, combined with K-Ar dating, petrochemistry, trace elemental geochemistry and isotopic compositions of the Mesozoic-Cenozoic volcanic rock in the Huanghua basin, Bohai region, the geochemical features of the volcanic rock were studied. The rocks fall into four groups: Cenozoic basalt, Mesozoic late Cretaceous basaltic-trachyandesite, Mesozoic late Cretaceous trachy-dacite and liparite, and Mesozoic early Triassic dacite. The distribution pattern of the main elemental abundance of late Mesozoic shows a typical bimodal. Chronologically, for the volcanic rock, the amount of SiO2 decreases gradually, the contents of Fe2O3,FeO,CaO,MgO,TiO2,P2O5 and MnO increase little by little. The Cenozoic basalt is derived from the asthenospheric mantle. The late Cretaceous basaltic-trachy-andesite is derived from the enriched lithospheric mantle. In late Cretaceous and early Palaeogene, the felsic volcanic rock may be derived from fractional melting of the crust.

  • Jian-ming Yi , Kuo-wen Tang , Bi-ye Ren , Hai-ying Xiong

    Cyclopropylamine is synthesized with γ-butyrolactone and isopropanol by five steps of ring-opening esterification, cyclization, hydrolysis, acylation and Hofmann degradation. Cyclization and hydrolysis are key steps in the process, and Phase Transfer Catalysis (PTC) is used in the two steps respectively. In the cyclization reaction, because solid-liquid PTC, sodium hydroxide is applied instead of expensive sodium alcoholate, the reaction can be carried out in mild conditions. The optimum reaction conditions are as follows: 0.03:1:1.5 mole ratio of BTEAC to ester to sodium hydroxide, reacting at 50 °C for 2 h with yield of 92%. Hydrolysis of isopropyl cyclopropanecarboxylate is accelerated by liquid-liquid PTC, and the order of catalytic activity is BTEC > BTMAC > CTMAB > TBAB. The results show that the new synthesis method is superior to those from literature and feasible for production with simple routes, mild reaction conditions, cheap materials and total yield of 52.6%.

  • Ming-hao Zhang , Chun-shan Zhou , Qian-hui Liu

    A polarographic catalytic wave of cobalt in the substrate solution (pH=8.5) of diacetyldioxime-potassium pyrophosphate-ammonium chloride was studied and a new method for rapid determination of trace cobalt in complex zinc electrolyte solution was developed. The results show that there is a very sensitive catalytic wave of cobalt at -1.23 V. At least three hundred thousand fold Zn2+ does not affect the determination of cobalt. The method is easy to operate and rapid, and when the signal-to-noise rate equals 2, the detection limit is 6 × 10−9 mol·L−1. A good linear relationship exists between the concentration of cobalt within 0.001–3.0 µg·mL−1 and the peak current. The method has successfully been used in the determination of trace cobalt in complex solution of the workshop for electrolyzing zinc.

  • Xin-yan Wang , Chun-shan Zhou , Yan Wang

    The separation of Co2+ from Zn2+, Cd2+ by anion-exchange chromatography was discussed. The chromatographic column containing anion resin 201 × 7 which was saturated with a solution of ammonium chloride. The effects of the eluant acidity and eluant composition on the separation were investigated. The results indicate that this anion-exchange chromatography is suitable to the separation of Co2+ from Zn2+, Cd2+, and the condition of separation is simple and convenient. When the column is saturated with NH4Cl solution (2.0 mol/L, pH=4.0), the separation can be completed effectively. Zn2+ and Cd2+ can also be separated when different eluants are used and the pure solution with high concentration of Zn2+, Cd2+ respectively can be obtained easily.

  • Hui-ping Hu , Ke-long Huang , Chun-yue Pan , De-ben Chen

    The effects of adding cosolvents of diglyme and 15-crown-5 to the reaction mixture of Wurtz-type coupling of dichlorosilanes on the yield and relative molecular mass dispersity of polymethylphenethylsilane(PMPES) were discussed. The results show that addition of 10% (volume ratio of diglyme to toluene) diglyme as a cosolvent to the reaction mixture leads to the yield increase of PMPES with a monomodal distribution of relative molecular masses. Adding 10% diglyme to the reaction mixtures, the yields of polymethylcyclohexylsilane(PMCS) and copolymers (polymethylphenethylsilane-co-methylcyclohexylsilane), (the molar ratios of methylphenethyldichlorosilane to methylcyclohexyldichlorosilane were 2.0, 1.0 and 0.5, and the copolymers were abbreviated by Copolymers I, II, III, respectively) are 47%, 52%, 54%, 53%, respectively. Their relative molecular masses

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    almost reach 105. These polysilanes were characterized by 1H-NMR, IR and UV absorption spectrum.

  • Song-qiao Chen , Hong Su

    Build a general software development platform for industrial process supervisor and management system by combining the technology of industrial configuration and Client/Server model, and introduce the architecture and topological application of this platform. It puts forward a solution to the real-time problem in the industrial distributed supervisor system.

  • Juan Liu , Zi-xing Cai , Jian-qin Liu

    An improved genetic algorithm (GA) is proposed based on the analysis of population diversity within the framework of Markov chain. The chaos operator to combat premature convergence concerning two goals of maintaining diversity in the population and sustaining the convergence capacity of the GA is introduced. In the CHaos Genetic Algorithm (CHGA), the population is recycled dynamically whereas the most highly fit chromosome is intact so as to restore diversity and reserve the best schemata which may belong to the optimal solution. The characters of chaos as well as advanced operators and parameter settings can improve both exploration and exploitation capacities of the algorithm. The results of multimodal function optimization show that CHGA performs simple genetic algorithms and effectively alleviates the problem of premature convergence.

  • Jia-yang Wang , Song-qiao Chen , Can-dong Wang

    The paper puts forward a highly efficient and practical scan-line based on the filling algorithm. The algorithm takes the lines of polygon as line segments with directions and introduces the concept of marked value when the apex of polygon faces scan-line, determines whether there are intersection points between the lines of polygon and scan-lines, by judging whether the marked value has changed or not. This method avoids the extra decision and treatment of odd points in traditional algorithm, and it needs little calculations but it is highly efficient.

  • Guang-hua Guo , R. Z. Levitin , N. P. Kolmakova

    Magnetic properties of a two-sublattice ferrimagnet with antiferromagnetic exchange interaction inside one of the sublattices are calculated within the framework of the molecular field theory taking into account the anisotropy of unstable sublattice. The magnetization curves of single crystal GdMn2Ge2 for the magnetic field parallel and perpendicular to the c-axis at different temperatures are calculated. Field-induced magnetic phase transitions in GdMn2Ge2 are discussed. Calculated H - T magnetic phase diagrams are in fair agreement with experimental data.

  • Yi-rong Liu , Ping Xiao

    Discuss a class of real planar cubic systems with a critical point O(0,0) of nine orders and obtain the conditions for its limit cycle surrounding the origin, and prove that when small pertubations of coefficients are made, the critical point O(0,0) of nine orders is split into nine real simple critical points and the limit cycle surrounding the origin becomes the limit cycle containing nine critical points in its interior.