The neutral zinc sulfate solution obtained from hydrometallurgical process of Angouran zinc concentrate has cadmium, nickel and cobalt impurities, that must be purified before electrowinning. Therefore, cadmium and ni...The neutral zinc sulfate solution obtained from hydrometallurgical process of Angouran zinc concentrate has cadmium, nickel and cobalt impurities, that must be purified before electrowinning. Therefore, cadmium and nickel are usually cemented out by addition of zinc dust and remained nickel and cobalt cemented out at second stage with zinc powder and arsenic trioxide. In this research, a new approach is described for determination of effective parameters and optimization of zinc electrolyte hot purification process using statistical design of experiments. The Taguchi method based on orthogonal array design（OAD） has been used to arrange the experimental runs. The experimental conditions involved in the work are as follows： the temperature range of 70-90 ℃ for reaction temperature（T）, 30-90 min for reaction time（t）, 2-4 g/L for zinc powder mass concentration（M）, one to five series for zinc dust particle size distributions（S1-S5）, and 0.1-0.5 g/L（C） for arsenic trioxide mass concentration. Optimum conditions for hot purification obtained in this work are T4（85 ℃）, t4=75 min, M4=3.5 g/L, S4（Serie 4）, and C2=0.2 g/L.展开更多
This study explores the Chinese public’s perceptions of, and attitudes to, agriculture and food applications of bio-technology; and investigates the effect of socio-demographic factors on attitudes. A questionnaire s...This study explores the Chinese public’s perceptions of, and attitudes to, agriculture and food applications of bio-technology; and investigates the effect of socio-demographic factors on attitudes. A questionnaire survey and interviews were used in an attempt to combine quantitative analysis with qualitative review. The main finding of this study is that the Chinese population has a superficial, optimistic attitude to agricultural biotechnology; and that, in accordance with public attitudes, a cautious policy, with obligatory labelling, should be adopted. The study reveals that education is the factor among socio-demographic variables with the strongest impact on public attitudes. Higher education leads to a more positive evaluation of GM (genetically modified) foods and applications of biotechnology with respect to usefulness, moral acceptability, and suitability for encouragement. In addition, public attitudinal differences depend significantly on area of residence. Compared with their more urban compatriots, members of the public in less developed areas of China have more optimistic attitudes, perceive more benefits, and are more risk tolerant in relation to GM foods and agricultural biotechnology. Finally we obtained a very high rate of “don’t know” answers to our survey questions. This suggests that many people do not have settled attitudes, and correspondingly, that the overall public attitude to agricultural biotechnology and GM foods in China is at present somewhat unstable.展开更多
In the present study,the effects of process parameters(output voltage x,nitrogen flux l and specific strengthening time s)on the microstructure and wear resistance properties of TiN coatings prepared by electrospark d...In the present study,the effects of process parameters(output voltage x,nitrogen flux l and specific strengthening time s)on the microstructure and wear resistance properties of TiN coatings prepared by electrospark deposition(ESD)were investigatedsystematically.The microstructure of the coatings was characterized for thickness(TOC),content of TiN(CON)and porosity(POC).A statistical model was developed to identify the significant factors affecting the microstructure and wear resistance of the coatings.The results show that the output voltage x and nitrogen flux l present significant effects on majority of the evaluation indexes such asTOC,friction coefficient(COF)and wear mass loss(Id),while the specific strengthening time s has a significant effect on POC and asmall effect on the other indexes.The optimal process parameters were obtained as follows:output voltage(x,60V),nitrogen flux(l,15L/min)and specific strengthening time(s,3min/cm2).The variation of wear mass loss(Id)by the variation of the outputvoltage(x)and nitrogen flux(l)is attributed to the change of wear mechanisms of TiN coatings.The main wear mechanism of TiNcoating prepared under optimal process parameters is micro-cutting wear accompanied by micro-fracture wear.展开更多
The amount of material must be removed away to produce the final product should minimize, excess stock will increase not only the material cost, but also processing cost, fixture cost, tooling cost, and increases mach...The amount of material must be removed away to produce the final product should minimize, excess stock will increase not only the material cost, but also processing cost, fixture cost, tooling cost, and increases machine cycle times. Noticing in recent years that the world is running out of mineral resources, and the price of engineering materials will continually rise in the future, the percentage of the cost of manufactured part that is due to the cost of materials is also rising. This paper proposed a variant CAPP system for rotational parts based on the concept of group technology, this system accepts part features characteristics code number as an input and provides operation details for manufacturing route with the suitable primary processes required to produce the blank work piece as an output.展开更多
To raise coal recovery ratio and solve the key problem of full-dimension mining, a new “3-section” technology of full-dimension mining is put forward in flat thick-seam according to the theory and mining practice. T...To raise coal recovery ratio and solve the key problem of full-dimension mining, a new “3-section” technology of full-dimension mining is put forward in flat thick-seam according to the theory and mining practice. This technology is proved to be rational and feasible in rodway layout system of stagger arrangement.展开更多
The necessi ty of product oriented integrated computer aided process planning (CAPP) is analy zed, and the system architecture and the main functions are described in detail. The key issues of the system, such as the ...The necessi ty of product oriented integrated computer aided process planning (CAPP) is analy zed, and the system architecture and the main functions are described in detail. The key issues of the system, such as the product oriented process planning me thod, the human machine cooperation in process planning, the generation of manu facture bill of material (MBOM) and the dynamic data exchanging technology betwe en CAPP and enterprise resource planning (ERP), are discussed. The CAPP system h as been applied at a CIMS environment corporation successfully.展开更多
文摘The neutral zinc sulfate solution obtained from hydrometallurgical process of Angouran zinc concentrate has cadmium, nickel and cobalt impurities, that must be purified before electrowinning. Therefore, cadmium and nickel are usually cemented out by addition of zinc dust and remained nickel and cobalt cemented out at second stage with zinc powder and arsenic trioxide. In this research, a new approach is described for determination of effective parameters and optimization of zinc electrolyte hot purification process using statistical design of experiments. The Taguchi method based on orthogonal array design（OAD） has been used to arrange the experimental runs. The experimental conditions involved in the work are as follows： the temperature range of 70-90 ℃ for reaction temperature（T）, 30-90 min for reaction time（t）, 2-4 g/L for zinc powder mass concentration（M）, one to five series for zinc dust particle size distributions（S1-S5）, and 0.1-0.5 g/L（C） for arsenic trioxide mass concentration. Optimum conditions for hot purification obtained in this work are T4（85 ℃）, t4=75 min, M4=3.5 g/L, S4（Serie 4）, and C2=0.2 g/L.
基金Project supported by the Ministry of Foreign Affairs, Denmark (No.104.p.3.kina.236) and the Natural Science Foundation (No.KYZ110303077) of Zhejiang Province, China
文摘This study explores the Chinese public’s perceptions of, and attitudes to, agriculture and food applications of bio-technology; and investigates the effect of socio-demographic factors on attitudes. A questionnaire survey and interviews were used in an attempt to combine quantitative analysis with qualitative review. The main finding of this study is that the Chinese population has a superficial, optimistic attitude to agricultural biotechnology; and that, in accordance with public attitudes, a cautious policy, with obligatory labelling, should be adopted. The study reveals that education is the factor among socio-demographic variables with the strongest impact on public attitudes. Higher education leads to a more positive evaluation of GM (genetically modified) foods and applications of biotechnology with respect to usefulness, moral acceptability, and suitability for encouragement. In addition, public attitudinal differences depend significantly on area of residence. Compared with their more urban compatriots, members of the public in less developed areas of China have more optimistic attitudes, perceive more benefits, and are more risk tolerant in relation to GM foods and agricultural biotechnology. Finally we obtained a very high rate of “don’t know” answers to our survey questions. This suggests that many people do not have settled attitudes, and correspondingly, that the overall public attitude to agricultural biotechnology and GM foods in China is at present somewhat unstable.
文摘In the present study,the effects of process parameters(output voltage x,nitrogen flux l and specific strengthening time s)on the microstructure and wear resistance properties of TiN coatings prepared by electrospark deposition(ESD)were investigatedsystematically.The microstructure of the coatings was characterized for thickness(TOC),content of TiN(CON)and porosity(POC).A statistical model was developed to identify the significant factors affecting the microstructure and wear resistance of the coatings.The results show that the output voltage x and nitrogen flux l present significant effects on majority of the evaluation indexes such asTOC,friction coefficient(COF)and wear mass loss(Id),while the specific strengthening time s has a significant effect on POC and asmall effect on the other indexes.The optimal process parameters were obtained as follows:output voltage(x,60V),nitrogen flux(l,15L/min)and specific strengthening time(s,3min/cm2).The variation of wear mass loss(Id)by the variation of the outputvoltage(x)and nitrogen flux(l)is attributed to the change of wear mechanisms of TiN coatings.The main wear mechanism of TiNcoating prepared under optimal process parameters is micro-cutting wear accompanied by micro-fracture wear.
文摘The amount of material must be removed away to produce the final product should minimize, excess stock will increase not only the material cost, but also processing cost, fixture cost, tooling cost, and increases machine cycle times. Noticing in recent years that the world is running out of mineral resources, and the price of engineering materials will continually rise in the future, the percentage of the cost of manufactured part that is due to the cost of materials is also rising. This paper proposed a variant CAPP system for rotational parts based on the concept of group technology, this system accepts part features characteristics code number as an input and provides operation details for manufacturing route with the suitable primary processes required to produce the blank work piece as an output.
基金The National Important Technique Innovation Item ( No.[2 0 0 1] 44 1)
文摘To raise coal recovery ratio and solve the key problem of full-dimension mining, a new “3-section” technology of full-dimension mining is put forward in flat thick-seam according to the theory and mining practice. This technology is proved to be rational and feasible in rodway layout system of stagger arrangement.
文摘The necessi ty of product oriented integrated computer aided process planning (CAPP) is analy zed, and the system architecture and the main functions are described in detail. The key issues of the system, such as the product oriented process planning me thod, the human machine cooperation in process planning, the generation of manu facture bill of material (MBOM) and the dynamic data exchanging technology betwe en CAPP and enterprise resource planning (ERP), are discussed. The CAPP system h as been applied at a CIMS environment corporation successfully.
