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电分扫描片的发展情况
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作者 王行恕 《印刷技术》 1990年第3期13-15,共3页
关键词 电分扫描 发展
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提升凹印电分质量的途经(下)
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作者 杨宗禄 童志敏 《印刷杂志》 2008年第5期61-64,共4页
电分调色是一门综合性较强的工作,有一定的艺术性和灵活性。艺术性表现为要真实表现出原稿的光线感、距离感、透视感、立体感,尽善尽美地再现原稿的艺术境界和丰富的色彩变化,使产品有强烈的视觉冲击力和耳目一新的视觉效果。灵活性... 电分调色是一门综合性较强的工作,有一定的艺术性和灵活性。艺术性表现为要真实表现出原稿的光线感、距离感、透视感、立体感,尽善尽美地再现原稿的艺术境界和丰富的色彩变化,使产品有强烈的视觉冲击力和耳目一新的视觉效果。灵活性则需要在实际工作中根据不同的原稿特性和印刷特性,合理选择电分工艺和调节方法,不可墨守成规。 展开更多
关键词 印前技术 凹版印刷 电分扫描 原稿 层次曲线 质量
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提升凹印电分质量的途径(上)
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作者 杨宗禄 童志敏 《印刷杂志》 2008年第4期42-43,共2页
凹印电雕工艺日趋完善,较好地解决和规范了电雕和打样的相关技术指标,进一步稳定了凹印产品的质量。但是,随着印刷技术的发展和人们欣赏水平的日益提高,传统的塑料包装产品应同时具备逼真性和观赏性,而且用户对图像的再现效果和质... 凹印电雕工艺日趋完善,较好地解决和规范了电雕和打样的相关技术指标,进一步稳定了凹印产品的质量。但是,随着印刷技术的发展和人们欣赏水平的日益提高,传统的塑料包装产品应同时具备逼真性和观赏性,而且用户对图像的再现效果和质量品质要求越来越高,电分质量的提高和产品返工率的减少便成为各凹印制版公司亟待解决的课题。影响电分质量、造成产品返工的原因,一般分为两类, 展开更多
关键词 印前技术 凹版印刷 电分扫描 原稿 层次曲线 质量
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印刷品再复制 一般规律的探讨
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作者 张继明 《中国印刷》 2000年第6期34-34,40,共2页
随着DTP在我国制版行业的全面展开,人们的制版观念,发生全新的变化,即电脑拓宽了原来电子分色机的功能,特别是Photoshop软件对图像的处理更是显示出了其强大的功能。过去在电分机上无法做到的,现在都可以一一做到,比如在对一些'非... 随着DTP在我国制版行业的全面展开,人们的制版观念,发生全新的变化,即电脑拓宽了原来电子分色机的功能,特别是Photoshop软件对图像的处理更是显示出了其强大的功能。过去在电分机上无法做到的,现在都可以一一做到,比如在对一些'非适性原稿'作特殊调整时,有可能会顾此失彼。 展开更多
关键词 电分扫描 PHOTOSHOP 套印调整 印刷复制品 制版
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Analysis of microscopic pore structures of rocks before and after water absorption 被引量:6
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作者 Li Dejian Wang Guilian +5 位作者 Han Liqiang Liu Peiyu He Manchao Yang Guoxing Tai Qimin Chen Cheng 《Mining Science and Technology》 EI CAS 2011年第2期287-293,共7页
Hydrophilic characteristics of rocks are affected by their microscopic pore structures,which clearly change after water absorption.Water absorption tests and scanning electron microscopic(SEM) experiments on rock sa... Hydrophilic characteristics of rocks are affected by their microscopic pore structures,which clearly change after water absorption.Water absorption tests and scanning electron microscopic(SEM) experiments on rock samples,located at a site in Tibet,China,were carried out Changes of rock pore structures before and after water absorption were studied with the distribution of pore sizes and fractal characteristics of pores.The results show that surface porosities,fractal dimensions of pores and the complexity of pore structures increased because the number of new small pores produced increased or the original macropore flow channels were expanded after rocks absorbed water.There were points of inflection on their water absorption curves.After water absorption of other rocks,surface porosities and fractal dimensions of pores and complexity of pore structures decreased as the original pore flow channels became filled.Water absorption curves did not change.Surface porosity and the pore fractal dimensions of rocks have good linear relationships before and after water absorption. 展开更多
关键词 Hydrophilic characteristics Pore structures Pore size distribution Pore fractal characteristics
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CT characteristics of ovarian dysgerminoma 被引量:2
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作者 Xiaoping Yu 《The Chinese-German Journal of Clinical Oncology》 CAS 2008年第12期735-737,共3页
Objective: To study the CT features of ovarian dysgerminoma. Methods: CT findings of 11 cases with pathologically-proved dysgerminoma of ovary were retrospectively analyzed. Results: All the 11 cases were solitary. Th... Objective: To study the CT features of ovarian dysgerminoma. Methods: CT findings of 11 cases with pathologically-proved dysgerminoma of ovary were retrospectively analyzed. Results: All the 11 cases were solitary. The maximum diameter of lesion was averagely 17.1 cm. The tumor presented as a solid (n = 8) or cystic-solid (n = 3) mass. After contrast medium administration, the solid component of the lesions showed prominent enhancement on CT scan. Blood vessels were found in 5 masses. Of the 11 cases with ovarian dysgerminoma, invasion of adjacent structure (n=4), ascites (n=6) and adenopathy in pelvic wall (n=3) were demonstrated. Conclusion: Ovarian dysgerminoma has its CT characteristics. Associated with clinic data, CT is helpful in the diagnosis and differential diagnosis of ovarian dysgerminoma. 展开更多
关键词 OVARY DYSGERMINOMA tomography X-ray computed
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Sedimentary characteristics and depositional model of a Paleocene-Eocene salt lake in the Jiangling Depression,China 被引量:10
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作者 余小灿 王春连 +6 位作者 刘成林 张招崇 徐海明 黄华 谢腾骁 李皓楠 刘锦磊 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2015年第6期1426-1435,共10页
We studied the sedimentary characteristics of a Paleocene-Eocene salt lake in the Jiangling Depression through field core observation,thin section identification,scanning electron microscopy,and X-ray diffraction anal... We studied the sedimentary characteristics of a Paleocene-Eocene salt lake in the Jiangling Depression through field core observation,thin section identification,scanning electron microscopy,and X-ray diffraction analysis.On the basis of sedimentary characteristics we have summarized the petrological and mineralogical characteristics of the salt lake and proposed 9 types of grade IV salt rhythms.The deposition shows a desalting to salting order of halite-argillaceous-mudstone-mud dolostonemud anhydrock-glauberite-halite.The relationship among grade IV rhythms,water salinity and climate fluctuations was analyzed.Based on the analysis of the relationship between boron content and mudstone color and by combining the mineralogy and sedimentary environment characteristics,we propose that the early and late Paleocene Shashi Formation in the Jiangling Depression was a paleolacustrine depositional environment with a high salt content,which is a representation of the shallow water salt lake depositional model.The middle Paleocene Shashi Formation and the early Eocene Xingouzui Formation were salt and brackish sedimentary environments with low salt content in a deep paleolake,which represents a deep salt lake depositional model. 展开更多
关键词 Paleocene-Eocene salt lake salt rhythm depositional model Jiangling Depression
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Kinetics analysis of Ni-TiO_2 composite system during initial stages of electro-crystallization 被引量:1
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作者 胡炜 谭澄宇 +2 位作者 崔航 刘宇 郑子樵 《Journal of Central South University》 SCIE EI CAS 2010年第3期460-466,共7页
The initial stage of Ni-TiO2 composite system electrodeposition on glassy carbon electrode from an acidic solution of nickel sulfate was investigated using cyclic voltammetry (CV), chronoamperometry (CA) and elect... The initial stage of Ni-TiO2 composite system electrodeposition on glassy carbon electrode from an acidic solution of nickel sulfate was investigated using cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS). Analysis of current density-time transients was performed using the nonlinear fitting procedure and electrochemical impedance spectroscopy was simulated by Z-view software. Besides, the surface morphology of Ni-TiO2 co-deposition at the initial stage was observed by scanning electron microscopy (SEM). The results show that, in the case of low overpotential (-790 mV vs SCE), the presence of TiO2 particles in the plating bath makes the nucleation relaxation time tm^x decreased clearly. Meanwhile, the electro-crystallization of Ni-TiO2 system follows a Scharifker-Hills (SH) progressive nucleation/growth mechanism. While in the case of higher overpotential, the presence of the TiO2 particles in solution makes the nucleation relaxation time tmax increased. At -850 mV (vs SCE), the co-deposition of Ni-TiO2 system meets SH instantaneous nucleation/growth mechanism. The results of impedance spectra show that the appearance of the characteristic inductive loops represents the nucleation/growth of nickel and the presence of TiO2 particles reduces the charge transfer resistance of solution. The SEM observation confirms that TiO2 particles can be considered as favorable sites for nickel nucleating. 展开更多
关键词 Ni-TiO2 system KINETICS electro-crystallization cyclic voltammetry electrochemical impedance spectroscopy
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Fabrication characteristics and tensile strength of novel Al2024/SiC/red mud composites processed via stir casting route 被引量:3
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作者 Jaswinder SINGH Amit CHAUHAN 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2017年第12期2573-2586,共14页
The stir casting technique was used to fabricate aluminum2024matrix hybrid composites reinforced with SiC(5%,mass fraction)and red mud(5%-20%,mass fraction)particles.The developed composites were characterized by usin... The stir casting technique was used to fabricate aluminum2024matrix hybrid composites reinforced with SiC(5%,mass fraction)and red mud(5%-20%,mass fraction)particles.The developed composites were characterized by using scanning electron microscopy(SEM)and electron dispersive spectrum(EDS)techniques.Further,Taguchi’s approach of experimental design was used to examine the tensile strength of the hybrid composites(with minimum number of experiments).It was found that the reinforcing particles were well dispersed and adequately bonded in the hybrid composites.The density and porosity of the hybrid composites were reduced with the increase in reinforcement content.The tensile strength of the composites increased with the increase in the red mud content and the ageing time.The developed model indicated that the red mud content had the highest influence on the tensile strength response followed by the ageing time.Overall,it was found that Al2024/SiC/red mud composites exhibited superior tensile strength(about34%higher)in comparison to the Al2024alloy under optimized conditions. 展开更多
关键词 aluminum matrix composites hybrid reinforcements tensile strength red mud stir casting statistical analysis scanning electron microscopy (SEM)
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Nanocrystalline Mg and Mg alloy powders by hydriding-dehydriding processing 被引量:4
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作者 王辛 王珩 +1 位作者 胡连喜 王尔德 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第7期1326-1330,共5页
The process of mechanically assisted hydriding and subsequent thermal dehydriding was proposed to produce nanocrystalline Mg and Mg alloy powders using pure Mg and Mg-5.5%Zn-0.6%Zr(mass fraction)(ZK60 Mg) alloy as the... The process of mechanically assisted hydriding and subsequent thermal dehydriding was proposed to produce nanocrystalline Mg and Mg alloy powders using pure Mg and Mg-5.5%Zn-0.6%Zr(mass fraction)(ZK60 Mg) alloy as the starting materal.The hydriding was achieved by room-temperature reaction milling in hydrogen.The dehydriding was carried out by vacuum annealing of the as-milled powders.The microstructure and morphology of both the as-milled and subsequently dehydrided powders were characterized by X-ray diffraction analysis(XRD) ,transmission electron microscopy(TEM) ,and scanning electron microscopy(SEM) ,respectively.The results show that,by reaction milling in hydrogen,both Mg and ZK60 Mg alloy can be fully hydrided to form nanocrystalline MgH2 with an average grain size of 10 nm.After subsequent thermal dehydriding at 300℃,the MgH2 can be turned into Mg again,and the newly formed Mg grains are nanocrystallines,with an average grain size of 25 nm. 展开更多
关键词 Mg Mg alloy HYDRIDING dehydriching hydrogen treatment NANOCRYSTALLINE
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Optimization of High-Gravity Chelated Iron Process for Removing H_2S Based on Response Surface Methodology 被引量:3
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作者 Luo Ying Zhang Zhongzhe +3 位作者 Qi Jibing Li Gang Qi Guisheng Liu Youzhi 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2015年第3期87-93,共7页
By using a mixture of N2 and H2S as the simulated APG(associated petroleum gas), the desulfurization experiment was performed in a cross-flow rotating packed bed(RPB) based on the chelated iron oxidation-reduction met... By using a mixture of N2 and H2S as the simulated APG(associated petroleum gas), the desulfurization experiment was performed in a cross-flow rotating packed bed(RPB) based on the chelated iron oxidation-reduction method. In order to determine the operating conditions of the system, the effects of the concentration of Fe3+ ions(ranging from 0.1 to 0.2 mol/L), the liquid-gas volume ratio(ranging from 15 to 25 L/m3) and the high gravity factor(ranging from 36 to 126) on the removal of H2 S were studied by means of the Box-Behnken design(BBD) under response surface methodology(RSM). The overall results have demonstrated that the BBD with an experimental design can be used effectively in the optimization of the desulfurization process. The optimal conditions based on both individualized and combined responses(at a Fe3+ ion concentration of 0.16 mol/L, a liquid-gas volume ratio of 20.67 L/m3 and a high gravity factor of 87) were found. Under this optimum condition, the desulfurization efficiency could reach 98.81% when the H2 S concentration was 7 g/m3 in APG. In this work, the sulfur product was analyzed by X-ray diffraction(XRD), scanning electron microscopy(SEM) and the energy dispersive X-ray spectrometer(EDX). The results of analysis show that the sulfur is made of the high-purity orthorhombic crystals, which are advantageous to environmental conservation. 展开更多
关键词 hydrogen sulfide chelated iron high gravity technology response surface methodology Box-Behnken design
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Effect of CaCO_3 on hydration characteristics of C_3A 被引量:1
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作者 肖佳 勾成福 +1 位作者 金勇刚 王永和 《Journal of Central South University》 SCIE EI CAS 2010年第5期918-923,共6页
Hydration products and morphology characteristics of C3A (tricalcium aluminate)-CaCO3-H2O system were studied by means of XRD, DSC, FTIR spectrum analysis and SEM. The results indicate that, the new phases, i.e., C3... Hydration products and morphology characteristics of C3A (tricalcium aluminate)-CaCO3-H2O system were studied by means of XRD, DSC, FTIR spectrum analysis and SEM. The results indicate that, the new phases, i.e., C3A·0.5CaCO3·0.5Ca(OH)2·11.5H2O and C3A·CaCO3·11H2O are found in this system due to the activity of CaC03; the formation of C4AH13 and C2AH8 is prohibited and the generation of C3AH6 is delayed in the early hydration process. C3A·0.5CaCO3·0.5Ca(OH)2.11.5HEO is not stable and will be totally transferred within 24 h; C3A·CaCO3.11H2O exists stably once formation, and its flake-like crystalline phases in the early hydration transform to long rod shape, and to finally fine-needle at 28 d. 展开更多
关键词 C3A CACO3 HYDRATION MORPHOLOGY
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Preparation of Phase Change Microcapsule and Its Plication in Textiles 被引量:1
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作者 闵洁 寿晨燕 《Journal of Donghua University(English Edition)》 EI CAS 2010年第3期419-424,共6页
Phase change microcapsules(PCMs)are prepared with n-hexadecane and n-octadecane as core material,and melamine-formaldehyde resin is used as shell material by in-situ polymerization.Differential scanning calorimetry(DS... Phase change microcapsules(PCMs)are prepared with n-hexadecane and n-octadecane as core material,and melamine-formaldehyde resin is used as shell material by in-situ polymerization.Differential scanning calorimetry(DSC)was used to analyze the phase change properties.Thermal conductivity and maximum heat flux of cotton fabric finished with PCMs before and after being washed were also measured.It has been found that melting and crystal enthalpy of the PCMs decrease with decreasing the core/shell ratio,while qmax of fabric treated with PCMs decreases and the thermal conductivity increases.Study shows that fabric finished by the PCMs has good temperature conditioning function. 展开更多
关键词 phase change microcapsules qmax thermal conductivity COTTON differential scanning calorimetry(DSC)
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Study on Hydrothermal Stability and Catalytic Activity of Al-SBA-15 Mesoporous Materials Prepared by Impregnation Method 被引量:6
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作者 Fu Jiquan Li Meng (Center of Chemical Engineering,Beijing Key Lab.,Beijing Institute of Fashion Technology,Beijing 100029) 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2011年第3期33-40,共8页
The mesoporous Al-SBA-15 zeolite was obtained via impregnation of pure silica-based SBA-15 zeolite with aluminum nitrate.The Al-SBA-15 sample was calcined in air at 800 ℃ for 6 h and hydrothermally treated at near 1... The mesoporous Al-SBA-15 zeolite was obtained via impregnation of pure silica-based SBA-15 zeolite with aluminum nitrate.The Al-SBA-15 sample was calcined in air at 800 ℃ for 6 h and hydrothermally treated at near 100 ℃ for 120 h,respectively,and then the thermal and hydrothermal stability of Al-SBA-15 sample was investigated by X-ray diffractometry (XRD),scanning electron microscopy (SEM),transmission electron microscopy (TEM) and nitrogen adsorption and desorption techniques.The Al-SBA-15 sample was also studied by 27 Al nuclear magnetic resonance (27 Al NMR) and ammonia temperature programmed desorption (NH 3-TPD) techniques.In addition,the catalytic activity of Al-SBA-15 zeolite was investigated by the Friedel-Crafts reactions of 2,4-di-tert-butylphenol with cinnamyl alcohol.The test results showed that the thermal and hydrothermal stability of Al-SBA-15 zeolite was better than that of SBA-15 zeo-lite.The Al-SBA-15 zeolite sample prepared by impregnation method exhibits more framework aluminum species and Al-O-Si units.Therefore,the number of the surface hydroxyl groups was reduced,resulting in the stabilization of framework structure ofAl-SBA-15 zeolite.The aluminum species can form weak and medium-strong acid sites with catalytic activity. 展开更多
关键词 Al-SBA-15 zeolite mesoporous material hydrothermal stability acid site catalytic activity
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Investigation of Different Coke Samples Adhering to Cyclone Walls of a Commercial RFCC Reactor 被引量:2
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作者 Li Xiaoman Song Jianfei +2 位作者 Sun Guogang Yan Chaoyu Wei Yaodong 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2016年第1期8-14,共7页
The microstructure and properties of the coke samples collected from 4 different wall regions of the cyclone in the reactor of a residue fluid catalytic cracking unit(RFCCU) were analyzed by using the scanning-electro... The microstructure and properties of the coke samples collected from 4 different wall regions of the cyclone in the reactor of a residue fluid catalytic cracking unit(RFCCU) were analyzed by using the scanning-electron microscope(SEM), and the possible coke formation processes were investigated as well. The results showed that some of the heavy nonvolatile oil droplets entrained in the flowing oil and gas mixture could possibly deposit or collide on the walls by gravity settling or turbulence diffusion, and then were gradually carbonized into solid coke by condensing and polymerization along with dehydrogenation. Meanwhile some of fine catalyst particles also built up and integrated into the solid coke. The coke can be classified into two types, namely, the hard coke and the soft coke, according to its property, composition and microstructure. The soft coke is formed in the oil and gas mixture's stagnant region where the oil droplets and catalyst particles are freely settled on the wall. The soft coke appears to be loose and contains lots of large catalyst particles. However, the hard coke is formed in the oil and gas mixture's flowing region where the oil droplets and catalyst particles diffuse towards the wall. This kind of coke is nonporous and very hard, which contains a few fine catalyst particles. Therefore, it is clear that the oil and gas mixture not only carries the oil droplets and catalyst particles, but also has the effects on their deposition on the wall, which can influence the composition and characteristics of deposited coke. 展开更多
关键词 FCC reactor cyclone coke formation microstructure characteristics
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Comparison of pore characteristics in the coal and shale reservoirs of Taiyuan Formation, Qinshui Basin, China 被引量:30
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作者 Yu Liu Yanming Zhu 《International Journal of Coal Science & Technology》 EI 2016年第3期330-338,共9页
Coal and shale are both unconventional gas reservoirs. Comparison of pore characteristics in shale and coal would help understand organic pore structure in shale and investigate co-exploration of shale gas and coalbed... Coal and shale are both unconventional gas reservoirs. Comparison of pore characteristics in shale and coal would help understand organic pore structure in shale and investigate co-exploration of shale gas and coalbed methane in coal bearing strata. In this study, five shale samples and three coal samples of Taiyuan Formation were collected from Qinshui Basin, China. High pressure mercury injection, scanning electronic microscopy, and fractal theory have been used to compare pore characteristics in shale and coal. The results show that pore volumes in coal are much larger than that in shale, especially pores 3-100 nm. In coal, there are many semi-closed pores in micro pores (〈10 nm) and transition pores (10-100 nm). On the contrary, micro pores and transition pores are mainly with open pores in shale. The fractal curves show that pores larger than 65 nm in coal and shale reservoir both have obvious self-similarity and the fractal dimension values in shale and coal are similar. But the fractal characteristics of pores smaller than 65 nm in shale reservoir are quite different from that in coal. 展开更多
关键词 COMPARISON COAL SHALE Organic pores FRACTAL
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Wear mechanism for spray deposited Al-Si/SiC_p composites under dry sliding condition 被引量:6
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作者 滕杰 李华培 陈刚 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第8期2875-2882,共8页
Al-Si/15%SiCp(volume fraction) composites with different silicon contents were fabricated by spray deposition technique, and typical microstructures of these composites were studied by optical microscopy(OM). Dry slid... Al-Si/15%SiCp(volume fraction) composites with different silicon contents were fabricated by spray deposition technique, and typical microstructures of these composites were studied by optical microscopy(OM). Dry sliding wear tests were carried out using a block-on-ring wear machine to investigate the effect of applied load range of 10-220 N on the wear and friction behavior of these composites sliding against SAE 52100 grade bearing steel. Scanning electron microscopy(SEM) and energy-dispersive X-ray microanalysis(EDAX) were utilized to examine the morphologies of the worn surfaces in order to observe the wear characteristics and investigate the wear mechanism. The results show that the wear behavior of these composites is dependent on the silicon content in the matrix alloy and the applied load. Al-Si/15%SiCp composites with higher silicon content exhibit better wear resistance in the applied load range. Under lower loads, the major wear mechanisms are oxidation wear and abrasive wear for all tested composites. Under higher loads, severe adhesive wear becomes the main wear mechanisms for Al-7Si/15%SiCp and Al-13Si/15%SiCp composites, while Al-20Si/15%SiCp presents a compound wear mechanism, consisting of oxidation, abrasive wear and adhesion wear. 展开更多
关键词 dry sliding wear wear mechanism Al-Si/SiC_p composites spray deposition
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PF/EP/Nano-SiO_2 Composite Paint for Resistor 被引量:1
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作者 王秀宇 张之圣 +3 位作者 白天 孙谷清 王金龙 黄翔东 《Transactions of Tianjin University》 EI CAS 2009年第4期283-287,共5页
Phenolic resin(PF) and nano-SiO2 were used to improve the curing property and high humidity resistance of epoxy resin (EP) and methyl nadic anhydride (MNA) resistor paint, respectively. Hydrogen bonds, formed between ... Phenolic resin(PF) and nano-SiO2 were used to improve the curing property and high humidity resistance of epoxy resin (EP) and methyl nadic anhydride (MNA) resistor paint, respectively. Hydrogen bonds, formed between phenolic resin and nano-SiO2 in alcohol, made nano-SiO2 disperse easily in EP/MNA paint through phenolic resin without being treated by supersonic vibration. When the mass ratio of PF to EP in paint is 3:7, the formed composite paint film can be cured in 2 min at 170 ℃ . When the mass ratio of nano-SiO2 to PF in paint is 3:100, the property of high humidity resistance of the composite paint is the best, meeting the requirement of varying ratio of resistance less than 0.1% after experiment on high humidity resistance. SEM analysis shows the surface of the composite paint film is smooth, glassy, tight and homogeneous, without acicular air holes. 展开更多
关键词 phenolic resin epoxy resin nano-SiO.~ paint for metal film resistor curing time high humidity resistance
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Separation of chalcopyrite and pyrite from a copper tailing by ammonium humate 被引量:9
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作者 Cuicui Lü Yongliang Wang +5 位作者 Peng Qian Ya Liu Guoyan Fu Jian Ding Shufeng Ye Yuanfa Chen 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2018年第9期1814-1821,共8页
Copper tailings constitute a large proportion of mine wastes. Some of the copper tailings can be recycled to recover valuable minerals. In this paper, a copper tailing was studied through the chemical analysis method,... Copper tailings constitute a large proportion of mine wastes. Some of the copper tailings can be recycled to recover valuable minerals. In this paper, a copper tailing was studied through the chemical analysis method, Xray diffraction and scanning electron microscope-energy dispersive spectrum. It turned out that chalcopyrite(Cu) and pyrite(S) were the main recoverable minerals in the tailing. In order to separate chalcopyrite from pyrite in low pulp pH, ammonium humate(AH) was singled out as the effective regulator. The depression mechanism of AH on the flotation of pyrite was proved by FTIR spectrum and XPS spectrum, demonstrating that there was a chemical adsorption between AH and pyrite. By Response Surface Methodology(RSM), the interaction between AH, pulp pH and iso-butyl ethionine(Z200) was discussed. It was illustrated that the optimal dosage of AH was 1678 g·t^(-1) involving both the recovery of Cu and S. The point prediction by RSM and the closed-circuit flotation displayed that the qualified Cu concentrate and S concentrate could be obtained from the copper tailing.The study indicated that AH was a promising pyrite depressor in the low pulp pH from copper tailings. 展开更多
关键词 Copper tailings Ammonium humate DEPRESSION Response Surface Methodology
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Fractal characteristics of cracks and fragments generated in unloading rockburst tests 被引量:12
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作者 Li Dejian Zhao Fei Zheng Maojiong 《International Journal of Mining Science and Technology》 SCIE EI 2014年第6期819-823,共5页
True triaxial rockburst experiments with four different unloading rates were performed on four prism specimens of granite sampled from Beishan, China. The damage evolution in the rockburst test was investigated from t... True triaxial rockburst experiments with four different unloading rates were performed on four prism specimens of granite sampled from Beishan, China. The damage evolution in the rockburst test was investigated from two aspects including fracture surface crack and fragment characteristics. The scanning electron microscopy was used to observe the micro crack information on fragment surface. Combing binarization and box counting dimensions, the fractal dimensions of cracks were obtained. Meanwhile,the fragments were collected and a sieving experiment was conducted. We weighed the fragments qualities, counted the amount of fragments and measured the fragments length, width and thickness.Utilizing four methods to calculate damage fractal dimensions of fragments, the trend of fractal value changing with unloading rates can be roughly described. It can be concluded from these experiments that the fractal dimension either for crack or for fragment holds a decreasing trend with the decreasing unloading rate, indicating a reduction of damage level. 展开更多
关键词 Unloading rockburst test Fragments Grain distribution Micro crack Fractal dimension
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