The re-release process and the release rate of heavy metals,cadmium and plumbum,which are rich in sediments of a certain water area,were investigated using a combined experimental and numerical method.Results show tha...The re-release process and the release rate of heavy metals,cadmium and plumbum,which are rich in sediments of a certain water area,were investigated using a combined experimental and numerical method.Results show that the release law of Cd and Pb in sediments is divided into two stages:rapid release and dynamic equilibrium,which is in great agreement with the pseudo second-order kinetic equation with a correlation coefficient R2 above 0.99.As the flow velocity accelerates,the release rate of heavy metals increases.The analysis results indicate that the water quality in the area can exceed the surface water Class V standard less than 3 h,and all but one of the relative deviations between the simulation value and the field survey result are within±10%.展开更多
Single hit compression tests were performed at 1 223-1 473 K and strain rate of 0.1-10 s-1 to study hot deformation behavior and flow stress model of F40MnV steel. The dependence of the peak stress, initial stress, sa...Single hit compression tests were performed at 1 223-1 473 K and strain rate of 0.1-10 s-1 to study hot deformation behavior and flow stress model of F40MnV steel. The dependence of the peak stress, initial stress, saturation stress, steady state stress and peak stain on Zener-Hollomon parameter were obtained. The mathematical models of dynamic recrystallization fraction and grain size were also obtained. Based on the tested data, the flow stress model of F40MnV steel was established in dynamic recovery region and dynamic recrystallization region, respectively. The results show that the activation energy for dynamic recrystallization is 278.6 kJ/mol by regression analysis. The flow stress model of F40MnV steel is proved to approximate the tested data and suitable for numerical simulation of hot forging.展开更多
The development and research on the recycle demetallating process are introduced. It shows the recycle demetallating process is effective on removing metal elements in heavy crude oil, especially with regard to calciu...The development and research on the recycle demetallating process are introduced. It shows the recycle demetallating process is effective on removing metal elements in heavy crude oil, especially with regard to calcium, through commercial application in delayed coking unit. Finally, the ash content in petroleum coke can be decreased to less than 0.5%, which complies with the IB coke standard. At the same time, the recycle demetallating process is an environmentally friendly technique, which has little effect on production quality and equipment corrosion.展开更多
Despite the advent of improved surgical techniques and the development of cytotoxic chemotherapeutic agents useful for the treatment of colorectal cancer,the primary clinical challenge remains that of preventing and c...Despite the advent of improved surgical techniques and the development of cytotoxic chemotherapeutic agents useful for the treatment of colorectal cancer,the primary clinical challenge remains that of preventing and combating metastatic spread.Surgical resection is the best treatment for colorectal metastases isolated to the liver.However,in rodent models,the hepatic ischemia-reperfusion(I/R) applied during the surgery accelerates the outgrowth of implanted tumors.Among the adverse effects of I/R on cellular function,several studies have demonstrated an over expression of the matrix metalloproteinase-9(MMP-9) in the ischemic liver.Since several studies showed high local levels of expression and activity of this proteolytic enzyme in the primary colorectal adenocarcinoma,the role of MMP-9 might be considered as a potential common mediator,favoring both growth of local tumor and the dissemination of colorectal carcinoma metastases.展开更多
The drawn copper wires have been analyzed by differential scanning calorimeter(DSC) and a new method, which uses DSC measurements to determine the Johnson-Mehl-Avrami-Kolmogorov(JMAK) exponent via introducing Arrheniu...The drawn copper wires have been analyzed by differential scanning calorimeter(DSC) and a new method, which uses DSC measurements to determine the Johnson-Mehl-Avrami-Kolmogorov(JMAK) exponent via introducing Arrhenius behavior and modifying the baseline of DSC curves, has been proposed. The results show that JMAK exponent and recrystallization activation energy of the drawn copper wires with a strain of 2.77 are about 2.39 and 125 k J/mol, respectively. The line linking the tangency points of DSC curve hypotenuse can be used as the baseline when calculating recrystallization fraction. The JMAK exponent obtained by the DSC method is in a good agreement with that obtained by microhardness measurements. Compared to traditional methods to measure the exponent, the proposed method is faster and less labor intensive.展开更多
Natural clay minerals can play an important role in crude remediation of wastewater polluted with the heavy metals （HMs） Cu, Zn and Ni. The presence and timing of ddition of natural dissolved organic matter （DOM） ...Natural clay minerals can play an important role in crude remediation of wastewater polluted with the heavy metals （HMs） Cu, Zn and Ni. The presence and timing of ddition of natural dissolved organic matter （DOM） have a significant effect on the HM removal by clay mineral sorbents. However, the influence of the presence of DOM on the remediation of the used clay mineral sorbents once saturated with HMs is largely unknown. To resolve this, clay mineral-rich soil column of varying composition, loaded （i） with Cu, Zn and Ni only, （ii） first with DOM followed by Cu, Zn and Ni, or （iii） with DOM, Cu, Zn and Ni simultaneously, was used in a set of desorption experiments. The soil columns were leached with 0.001 mol L-1 CaCI2 dissolved in water as control eluent and 0.001 tool L-1 CaC12 dissolved in DOM as treatment eluent. During the preceding loading phase of the sorbent, the timing of DOM addition （sequential or concurrent with HMs） was found to have a significant influence on the subsequent removal of the HMs. In particular when the column was loaded with DOM and HMs simultaneously, largely irreversible co-precipitation took place. Our results indicate that the regeneration potential of clay mineral sorbents in wastewater treatment will be significantly reduced when the treated water is rich in DOM. In contrast, in manured agricultural fields （where HMs enter together with DOM）, HM mobility will be lower than expected from interaction dynamics of HMs and clay minerals.展开更多
Ten of thousands of aircraft are expected to retire in the next 20 years.Aircraft manufacturers are gearing up for a new wave of recycling challenges as these aircrafts contain significant higher amount of carbon fibr...Ten of thousands of aircraft are expected to retire in the next 20 years.Aircraft manufacturers are gearing up for a new wave of recycling challenges as these aircrafts contain significant higher amount of carbon fibre reinforced polymer composite,which cannot be recycled by the conventional processes designed for metallic alloys.Aircraft manufacturers have been working with the recycling industry to limit unsustainable dismantling that is harmful to the environment and the potential liability risk of re-entry of un-certified salvaged parts back to the aviation market.An organised recycling network and procedures have already been set up for the conventional metallic alloys and will soon be required to include the composite waste.This paper reports the existing aircraft recycling practice and reviews the key recycling technologies for thermoset composites.Energy consumptions of these technologies are sought from the literature and are reported in this paper.Progress in development of reuse options for the recycled fibre is also included with discussion of their advantages and drawbacks.The challenge of working with the fluffy fibre is considered and the benefit of fibre alignment is highlighted for encouraging a widespread use of the fibre.展开更多
Catalysts of oxygen reduction reaction （ORR） play key roles in renewable energy technologies such as metal-air batteries and fuel cells. Despite tremendous ef- forts, highly active catalysts with low cost remain elu...Catalysts of oxygen reduction reaction （ORR） play key roles in renewable energy technologies such as metal-air batteries and fuel cells. Despite tremendous ef- forts, highly active catalysts with low cost remain elusive. This work used metal-organic frameworks to synthesize non-precious bimetallic carbon nanocomposites as efficient ORR catalysts. Although carbon-based Cu and Ni are good candidates, the hybrid nanocomposites take advantage of both metals to improve catalytic activity. The resulting molar ratio of Cu/Ni in the nanocomposites can be finely controlled by tuning the recipe of the precursors. Nanocom- posites with a series of molar ratios were produced, and they exhibited much better ORR catalytic performance than their monometallic counterparts in terms of limited current density, onset potential and half-wave potential. In addition, their extraordinary stability in alkaline is superior to that of commercially-available Pt-based materials, which adds to the appeal of the bimetallic carbon nanocomposites as ORR catalysts. Their improved performance can be attributed to the synergetic effects of Cu and Ni, and the enhancement of the carbon matrix.展开更多
基金The authors are grateful for the financial supports from the National Key R&D Program of China(2018YFC1903301).
文摘The re-release process and the release rate of heavy metals,cadmium and plumbum,which are rich in sediments of a certain water area,were investigated using a combined experimental and numerical method.Results show that the release law of Cd and Pb in sediments is divided into two stages:rapid release and dynamic equilibrium,which is in great agreement with the pseudo second-order kinetic equation with a correlation coefficient R2 above 0.99.As the flow velocity accelerates,the release rate of heavy metals increases.The analysis results indicate that the water quality in the area can exceed the surface water Class V standard less than 3 h,and all but one of the relative deviations between the simulation value and the field survey result are within±10%.
基金Project (50275094) supported by the National Natural Science Foundation of China
文摘Single hit compression tests were performed at 1 223-1 473 K and strain rate of 0.1-10 s-1 to study hot deformation behavior and flow stress model of F40MnV steel. The dependence of the peak stress, initial stress, saturation stress, steady state stress and peak stain on Zener-Hollomon parameter were obtained. The mathematical models of dynamic recrystallization fraction and grain size were also obtained. Based on the tested data, the flow stress model of F40MnV steel was established in dynamic recovery region and dynamic recrystallization region, respectively. The results show that the activation energy for dynamic recrystallization is 278.6 kJ/mol by regression analysis. The flow stress model of F40MnV steel is proved to approximate the tested data and suitable for numerical simulation of hot forging.
文摘The development and research on the recycle demetallating process are introduced. It shows the recycle demetallating process is effective on removing metal elements in heavy crude oil, especially with regard to calcium, through commercial application in delayed coking unit. Finally, the ash content in petroleum coke can be decreased to less than 0.5%, which complies with the IB coke standard. At the same time, the recycle demetallating process is an environmentally friendly technique, which has little effect on production quality and equipment corrosion.
基金Supported by The Swiss National Science Foundation,No. 32003B-134963/1,to Montecucco FEU FP7 Athero-Remo,No. 201668Swiss National Science Foundation,No. 310030B-133127,to Mach F
文摘Despite the advent of improved surgical techniques and the development of cytotoxic chemotherapeutic agents useful for the treatment of colorectal cancer,the primary clinical challenge remains that of preventing and combating metastatic spread.Surgical resection is the best treatment for colorectal metastases isolated to the liver.However,in rodent models,the hepatic ischemia-reperfusion(I/R) applied during the surgery accelerates the outgrowth of implanted tumors.Among the adverse effects of I/R on cellular function,several studies have demonstrated an over expression of the matrix metalloproteinase-9(MMP-9) in the ischemic liver.Since several studies showed high local levels of expression and activity of this proteolytic enzyme in the primary colorectal adenocarcinoma,the role of MMP-9 might be considered as a potential common mediator,favoring both growth of local tumor and the dissemination of colorectal carcinoma metastases.
基金Projects(51171135,51371132,51471123) supported by the National Natural Science Foundation of ChinaProjects(2012K07-08,2013KJXX-61) supported by Key Science and Technology Program of Shaanxi Province,ChinaProject(2013JC14) supported by the Education Department Foundation of Shaanxi Province,China
文摘The drawn copper wires have been analyzed by differential scanning calorimeter(DSC) and a new method, which uses DSC measurements to determine the Johnson-Mehl-Avrami-Kolmogorov(JMAK) exponent via introducing Arrhenius behavior and modifying the baseline of DSC curves, has been proposed. The results show that JMAK exponent and recrystallization activation energy of the drawn copper wires with a strain of 2.77 are about 2.39 and 125 k J/mol, respectively. The line linking the tangency points of DSC curve hypotenuse can be used as the baseline when calculating recrystallization fraction. The JMAK exponent obtained by the DSC method is in a good agreement with that obtained by microhardness measurements. Compared to traditional methods to measure the exponent, the proposed method is faster and less labor intensive.
基金supported by a scholarship from the Faculty of Science, University of Amsterdam, The Netherlands
文摘Natural clay minerals can play an important role in crude remediation of wastewater polluted with the heavy metals （HMs） Cu, Zn and Ni. The presence and timing of ddition of natural dissolved organic matter （DOM） have a significant effect on the HM removal by clay mineral sorbents. However, the influence of the presence of DOM on the remediation of the used clay mineral sorbents once saturated with HMs is largely unknown. To resolve this, clay mineral-rich soil column of varying composition, loaded （i） with Cu, Zn and Ni only, （ii） first with DOM followed by Cu, Zn and Ni, or （iii） with DOM, Cu, Zn and Ni simultaneously, was used in a set of desorption experiments. The soil columns were leached with 0.001 mol L-1 CaCI2 dissolved in water as control eluent and 0.001 tool L-1 CaC12 dissolved in DOM as treatment eluent. During the preceding loading phase of the sorbent, the timing of DOM addition （sequential or concurrent with HMs） was found to have a significant influence on the subsequent removal of the HMs. In particular when the column was loaded with DOM and HMs simultaneously, largely irreversible co-precipitation took place. Our results indicate that the regeneration potential of clay mineral sorbents in wastewater treatment will be significantly reduced when the treated water is rich in DOM. In contrast, in manured agricultural fields （where HMs enter together with DOM）, HM mobility will be lower than expected from interaction dynamics of HMs and clay minerals.
文摘Ten of thousands of aircraft are expected to retire in the next 20 years.Aircraft manufacturers are gearing up for a new wave of recycling challenges as these aircrafts contain significant higher amount of carbon fibre reinforced polymer composite,which cannot be recycled by the conventional processes designed for metallic alloys.Aircraft manufacturers have been working with the recycling industry to limit unsustainable dismantling that is harmful to the environment and the potential liability risk of re-entry of un-certified salvaged parts back to the aviation market.An organised recycling network and procedures have already been set up for the conventional metallic alloys and will soon be required to include the composite waste.This paper reports the existing aircraft recycling practice and reviews the key recycling technologies for thermoset composites.Energy consumptions of these technologies are sought from the literature and are reported in this paper.Progress in development of reuse options for the recycled fibre is also included with discussion of their advantages and drawbacks.The challenge of working with the fluffy fibre is considered and the benefit of fibre alignment is highlighted for encouraging a widespread use of the fibre.
基金supported by the National Natural Science Foundation of China (21671096 and 21603094)the Natural Science Foundation of Shenzhen (JCYJ20150630145302231 and JCYJ20150331101823677)the Science and Technology Innovation Foundation for the Undergraduates of SUSTech (2014S07, 2016S10 and 2016S20)
文摘Catalysts of oxygen reduction reaction （ORR） play key roles in renewable energy technologies such as metal-air batteries and fuel cells. Despite tremendous ef- forts, highly active catalysts with low cost remain elusive. This work used metal-organic frameworks to synthesize non-precious bimetallic carbon nanocomposites as efficient ORR catalysts. Although carbon-based Cu and Ni are good candidates, the hybrid nanocomposites take advantage of both metals to improve catalytic activity. The resulting molar ratio of Cu/Ni in the nanocomposites can be finely controlled by tuning the recipe of the precursors. Nanocom- posites with a series of molar ratios were produced, and they exhibited much better ORR catalytic performance than their monometallic counterparts in terms of limited current density, onset potential and half-wave potential. In addition, their extraordinary stability in alkaline is superior to that of commercially-available Pt-based materials, which adds to the appeal of the bimetallic carbon nanocomposites as ORR catalysts. Their improved performance can be attributed to the synergetic effects of Cu and Ni, and the enhancement of the carbon matrix.
