Demand is growing for explosive-free rock breakage systems for civil and mining engineering, and space industry applications. This paper highlights the work being undertaken in the Geomechanics Laboratory of Mc Gill U...Demand is growing for explosive-free rock breakage systems for civil and mining engineering, and space industry applications. This paper highlights the work being undertaken in the Geomechanics Laboratory of Mc Gill University to make a real application of microwave-assisted mechanical rock breakage to fullface tunneling machines and drilling. Comprehensive laboratory tests investigated the effect of microwave radiation on temperature profiles and strength reduction in hard rocks(norite, granite, and basalt)for a range of exposure times and microwave power levels. The heating rate on the surface of the rock specimens linearly decreased with distance between the sample and the microwave antenna, regardless of microwave power level and exposure time. Tensile and uniaxial compressive strengths were reduced with increasing exposure time and power level. Scanning electron micrographs(SEMs) highlighted fracture development in treated basalt. It was concluded that the microwave power level has a strong positive influence on the amount of heat damage induced to the rock surface. Numerical simulations of electric field intensity and wave propagation conducted with COMSOL Multiphysics~ software generated temperature profiles that were in close agreement with experimental results.展开更多
The property of extraction solution is an important factor influencing the extraction efficiency. In the present work, the effect of the property of solution on extraction of GA was studied, which including the concen...The property of extraction solution is an important factor influencing the extraction efficiency. In the present work, the effect of the property of solution on extraction of GA was studied, which including the concentration of ethanol, ammonia and cation (M+), pH of extraction solution, different kinds of organic solvent etc. The results show that 50%-60%(v/v) ethanol can reach high percentage extraction of GA. If 1% (v/v) ammonia solution was added into 60%(v/v) ethanol, the percentage extraction can be increased from 2.0% to 2.31%. Without ammonia, 50mmol/L [M+] (M+ = K+, NH4+) was added into 60%(v/v) ethanol, percentage extraction of GA can reach about 2.26%. If pH of solution (60% ethanol) was adjust to pH=4.0, it can reach high percentage extraction. If pH of solution (60% ethanol + 50mmol [M+], pH=6.1) was adjust tO PH=4.0, especially M+ is K+ or NH4+, it can reach almost same extraction efficiency as that of 1% ammonia solution + 60% ethanol, and the operation environment can be greatly improved.展开更多
运用响应曲面法优化铜藻多糖(tong zao polysaccharide,TZP)微波辅助提取的工艺条件,利用分级醇沉法得到TZP30%、TZP60%和TZP80%3个多糖组分。并对其DPPH自由基、ABTS自由基、OH自由基和O2-自由基的清除能力及其还原力进行了研究。结果...运用响应曲面法优化铜藻多糖(tong zao polysaccharide,TZP)微波辅助提取的工艺条件,利用分级醇沉法得到TZP30%、TZP60%和TZP80%3个多糖组分。并对其DPPH自由基、ABTS自由基、OH自由基和O2-自由基的清除能力及其还原力进行了研究。结果表明:铜藻多糖微波辅助提取的最佳条件为料液比1:65,提取温度72℃,提取时间39min,多糖提取率为12.02%(n=3);在试验浓度范围内,TZP30%组分对羟基自由基的清除能力最高达98.07%;TZP60%组分对DPPH自由基清除能力最高达85.01%;TZP80%组分对ABTS自由基清除能力较强,还原力较大。铜藻多糖具有较高的抗氧化活性,具有作为天然抗氧化剂的应用前景。展开更多
Ginsenosides Rgl, Re, Rb1, Rc, Rb2, Rb3, and Rd in different parts of the American ginseng plant were investigated. The extraction process was a pressurized microwave-assisted extraction（PMAE）. The seven ginsenoside...Ginsenosides Rgl, Re, Rb1, Rc, Rb2, Rb3, and Rd in different parts of the American ginseng plant were investigated. The extraction process was a pressurized microwave-assisted extraction（PMAE）. The seven ginsenosides were separated and determined by high-performance liquid chromatography（HPLC） with a ultraviolet（UV） detector, at 203 nm. The experiment results showed significant variations in the individual ginsenoside contents of the American ginseng in different parts and ages of the plant. The results demonstrated that the leaves, root hairs, and rhizomes of Panax quinquefolius L. contained higher ginsenoside contents, followed by the main roots and stems. The leaves contained dramatically higher levels of ginsenoside Rg1 Rb3, and Rd than the other four parts. Higher contents of Rb1 and Re were present in the main roots, root hairs, and rhizomes. The amount of ginsenoside content in the stems was the lowest. The total content of the seven ginsenosides in main roots, root hairs and rhizomes increased with the age of the plant. In contrast, the ginsenoside contents in the leaves and stems decreased with a year of growth.展开更多
基金the Natural Sciences and Engineering Research Council of Canada(NSERC)with the collaboration of IAMGold,Glencore,and Vale Canada,who generously contributed financially to this research project
文摘Demand is growing for explosive-free rock breakage systems for civil and mining engineering, and space industry applications. This paper highlights the work being undertaken in the Geomechanics Laboratory of Mc Gill University to make a real application of microwave-assisted mechanical rock breakage to fullface tunneling machines and drilling. Comprehensive laboratory tests investigated the effect of microwave radiation on temperature profiles and strength reduction in hard rocks(norite, granite, and basalt)for a range of exposure times and microwave power levels. The heating rate on the surface of the rock specimens linearly decreased with distance between the sample and the microwave antenna, regardless of microwave power level and exposure time. Tensile and uniaxial compressive strengths were reduced with increasing exposure time and power level. Scanning electron micrographs(SEMs) highlighted fracture development in treated basalt. It was concluded that the microwave power level has a strong positive influence on the amount of heat damage induced to the rock surface. Numerical simulations of electric field intensity and wave propagation conducted with COMSOL Multiphysics~ software generated temperature profiles that were in close agreement with experimental results.
基金Supported by the National Natural Science Foundation of China(No.29836130).
文摘The property of extraction solution is an important factor influencing the extraction efficiency. In the present work, the effect of the property of solution on extraction of GA was studied, which including the concentration of ethanol, ammonia and cation (M+), pH of extraction solution, different kinds of organic solvent etc. The results show that 50%-60%(v/v) ethanol can reach high percentage extraction of GA. If 1% (v/v) ammonia solution was added into 60%(v/v) ethanol, the percentage extraction can be increased from 2.0% to 2.31%. Without ammonia, 50mmol/L [M+] (M+ = K+, NH4+) was added into 60%(v/v) ethanol, percentage extraction of GA can reach about 2.26%. If pH of solution (60% ethanol) was adjust to pH=4.0, it can reach high percentage extraction. If pH of solution (60% ethanol + 50mmol [M+], pH=6.1) was adjust tO PH=4.0, especially M+ is K+ or NH4+, it can reach almost same extraction efficiency as that of 1% ammonia solution + 60% ethanol, and the operation environment can be greatly improved.
文摘运用响应曲面法优化铜藻多糖(tong zao polysaccharide,TZP)微波辅助提取的工艺条件,利用分级醇沉法得到TZP30%、TZP60%和TZP80%3个多糖组分。并对其DPPH自由基、ABTS自由基、OH自由基和O2-自由基的清除能力及其还原力进行了研究。结果表明:铜藻多糖微波辅助提取的最佳条件为料液比1:65,提取温度72℃,提取时间39min,多糖提取率为12.02%(n=3);在试验浓度范围内,TZP30%组分对羟基自由基的清除能力最高达98.07%;TZP60%组分对DPPH自由基清除能力最高达85.01%;TZP80%组分对ABTS自由基清除能力较强,还原力较大。铜藻多糖具有较高的抗氧化活性,具有作为天然抗氧化剂的应用前景。
基金Supported by the National Natural Science Foundation of China(No.20875037)
文摘Ginsenosides Rgl, Re, Rb1, Rc, Rb2, Rb3, and Rd in different parts of the American ginseng plant were investigated. The extraction process was a pressurized microwave-assisted extraction（PMAE）. The seven ginsenosides were separated and determined by high-performance liquid chromatography（HPLC） with a ultraviolet（UV） detector, at 203 nm. The experiment results showed significant variations in the individual ginsenoside contents of the American ginseng in different parts and ages of the plant. The results demonstrated that the leaves, root hairs, and rhizomes of Panax quinquefolius L. contained higher ginsenoside contents, followed by the main roots and stems. The leaves contained dramatically higher levels of ginsenoside Rg1 Rb3, and Rd than the other four parts. Higher contents of Rb1 and Re were present in the main roots, root hairs, and rhizomes. The amount of ginsenoside content in the stems was the lowest. The total content of the seven ginsenosides in main roots, root hairs and rhizomes increased with the age of the plant. In contrast, the ginsenoside contents in the leaves and stems decreased with a year of growth.
