A series of centrifuge model tests of sandy slopes were conducted to study the dynamic behavior of pile-reinforced slopes subjected to various motions.Time histories of accelerations,bending moments and pile earth pre...A series of centrifuge model tests of sandy slopes were conducted to study the dynamic behavior of pile-reinforced slopes subjected to various motions.Time histories of accelerations,bending moments and pile earth pressures were obtained during excitation of the adjusted El Centro earthquake and a cyclic motion.Under a realistic earthquake,the overall response of the pile-reinforced slope is lower than that of the non-reinforced slope.The histories of bending moments and dynamic earth pressures reach their maximums soon after shaking started and then remain roughly stable until the end of shaking.Maximum moments occur at the height of 3.5 m,which is the deeper section of the pile,indicating the interface between the active loading and passive resistance regions.The dynamic earth pressures above the slope base steadily increase with the increase of height of pile.For the model under cyclic input motion,response amplitudes at different locations in the slope are almost the same,indicating no significant response amplification.Both the bending moment and earth pressure increase gradually over a long period.展开更多
Carbonate decomposition of carbonic refractory gold ore and the following pressure oxidation were studied.In the carbonate decomposition procedure,the effects of liquid-to-solid ratio and reaction time on decompositio...Carbonate decomposition of carbonic refractory gold ore and the following pressure oxidation were studied.In the carbonate decomposition procedure,the effects of liquid-to-solid ratio and reaction time on decomposition ratio of carbonate were investigated.The experimental result shows that the decomposition ratio of carbonate is 98.24%under the conditions of liquid-to-solid ratio of 5:1,Fe^(3+)concentration of 20 g/L,sulfuric acid concentration of 20 g/L,reaction temperature of 80 ℃ and reaction time of 2 h.Then,the slurry obtained from carbonate decomposition was put into the titanium autoclave for pressure oxidation leaching.Effects of liquid-to-solid ratio,temperature,time and oxygen partial pressure on sulfur oxidation ratio were studied during pressure oxidation.With the prolonged time,pyrite and arsenopyrite are oxidized to ferric subsulfate,hydrated ferric sulfate and jarosite,resulting in the increasing residue ratio.The residue ratio and the sulfur content in the residue can be decreased by ferric subsulfate dissolution.The oxidation ratio of the sulfur is 99.35% under the conditions of oxidation time of 4 h,temperature of 210 ℃,oxygen partial pressure of 0.8 MPa and stirring speed of 600 r/min.展开更多
Purpose： The objective of this study was to investigate the effects of chronic Rhodiola rosea （R. rosea） supplementation on mental and physical performance, as well as hormonal and oxidative stress biomarkers. Meth...Purpose： The objective of this study was to investigate the effects of chronic Rhodiola rosea （R. rosea） supplementation on mental and physical performance, as well as hormonal and oxidative stress biomarkers. Methods： Twenty-six healthy male students received either R. rosea extract （600 mg/day; RR） or placebo （PL） in a randomized double-blind trial. Prior to supplementation （Term I） and following 4 weeks of supplementation （Term II）, the students underwent psychomotor tests for simple and choice reaction time, included in the Vienna Test System. Also, the subjects performed VO2peak test. Blood samples were obtained before and after the test to measure the hormonal profile （cortisol, testosterone, and growth hormone）, as well as the biomarkers of oxidative stress （lipid hydroperoxides, total antioxidant capacity, and superoxide dismutase） and muscle damage （creatine kinase）. Results： R. rosea ingestion shortened reaction time and total response time. Moreover, a greater relative increase in the number of correct responses was observed in RR group as compared to the PL group. No changes in endurance exercise capacity and hormonal profile were observed after R. rosea ingestion. R. rosea ingestion raised plasma total antioxidant capacity. It did not, however, affect other measured parameters. Conclusion： Chronic R. rosea ingestion does not affect physical performance, but can improve the results of some psychomotor tests （simple and choice reaction time） in young, healthy, and physically active men. The improvements in mental performance, however, at least in our study, seem not to be related to changes in cortisol release or antioxidant activity of R. rosea extract. Thus, the specific mechanisms responsible for these effects still need to be elucidated.2018 Published by Elsevier B.V. on behalf of Shanghai University of Sport. This is an open access article under the CC BY-NC-ND license. （http：//creativecommons.org/licenses/by-nc-nd/4.0/）.展开更多
基金Project(50639060) supported by the National Natural Science Foundation of ChinaProject(610103002) supported by the State Key Laboratory of Hydroscience and Engineering,Tsinghua University,China
文摘A series of centrifuge model tests of sandy slopes were conducted to study the dynamic behavior of pile-reinforced slopes subjected to various motions.Time histories of accelerations,bending moments and pile earth pressures were obtained during excitation of the adjusted El Centro earthquake and a cyclic motion.Under a realistic earthquake,the overall response of the pile-reinforced slope is lower than that of the non-reinforced slope.The histories of bending moments and dynamic earth pressures reach their maximums soon after shaking started and then remain roughly stable until the end of shaking.Maximum moments occur at the height of 3.5 m,which is the deeper section of the pile,indicating the interface between the active loading and passive resistance regions.The dynamic earth pressures above the slope base steadily increase with the increase of height of pile.For the model under cyclic input motion,response amplitudes at different locations in the slope are almost the same,indicating no significant response amplification.Both the bending moment and earth pressure increase gradually over a long period.
基金Project(51404296)supported by the Young Scientists Fund of National Natural Science Foundation of ChinaProject(134414)supported by the Postdoctoral Funded Program of Central South University,China
文摘Carbonate decomposition of carbonic refractory gold ore and the following pressure oxidation were studied.In the carbonate decomposition procedure,the effects of liquid-to-solid ratio and reaction time on decomposition ratio of carbonate were investigated.The experimental result shows that the decomposition ratio of carbonate is 98.24%under the conditions of liquid-to-solid ratio of 5:1,Fe^(3+)concentration of 20 g/L,sulfuric acid concentration of 20 g/L,reaction temperature of 80 ℃ and reaction time of 2 h.Then,the slurry obtained from carbonate decomposition was put into the titanium autoclave for pressure oxidation leaching.Effects of liquid-to-solid ratio,temperature,time and oxygen partial pressure on sulfur oxidation ratio were studied during pressure oxidation.With the prolonged time,pyrite and arsenopyrite are oxidized to ferric subsulfate,hydrated ferric sulfate and jarosite,resulting in the increasing residue ratio.The residue ratio and the sulfur content in the residue can be decreased by ferric subsulfate dissolution.The oxidation ratio of the sulfur is 99.35% under the conditions of oxidation time of 4 h,temperature of 210 ℃,oxygen partial pressure of 0.8 MPa and stirring speed of 600 r/min.
基金financed by the project of Józef Pilsudski University of Physical Education in Warsaw,Faculty of Physical Education and Sport in Biala Podlaska BW/Ⅲ/27
文摘Purpose： The objective of this study was to investigate the effects of chronic Rhodiola rosea （R. rosea） supplementation on mental and physical performance, as well as hormonal and oxidative stress biomarkers. Methods： Twenty-six healthy male students received either R. rosea extract （600 mg/day; RR） or placebo （PL） in a randomized double-blind trial. Prior to supplementation （Term I） and following 4 weeks of supplementation （Term II）, the students underwent psychomotor tests for simple and choice reaction time, included in the Vienna Test System. Also, the subjects performed VO2peak test. Blood samples were obtained before and after the test to measure the hormonal profile （cortisol, testosterone, and growth hormone）, as well as the biomarkers of oxidative stress （lipid hydroperoxides, total antioxidant capacity, and superoxide dismutase） and muscle damage （creatine kinase）. Results： R. rosea ingestion shortened reaction time and total response time. Moreover, a greater relative increase in the number of correct responses was observed in RR group as compared to the PL group. No changes in endurance exercise capacity and hormonal profile were observed after R. rosea ingestion. R. rosea ingestion raised plasma total antioxidant capacity. It did not, however, affect other measured parameters. Conclusion： Chronic R. rosea ingestion does not affect physical performance, but can improve the results of some psychomotor tests （simple and choice reaction time） in young, healthy, and physically active men. The improvements in mental performance, however, at least in our study, seem not to be related to changes in cortisol release or antioxidant activity of R. rosea extract. Thus, the specific mechanisms responsible for these effects still need to be elucidated.2018 Published by Elsevier B.V. on behalf of Shanghai University of Sport. This is an open access article under the CC BY-NC-ND license. （http：//creativecommons.org/licenses/by-nc-nd/4.0/）.
